Characterization of mercury bioremediation by transgenic bacteria expressing metallothionein and polyphosphate kinase

PubMed Central

2011-01-01

Background The use of transgenic bacteria has been proposed as a suitable alternative for mercury remediation. Ideally, mercury would be sequestered by metal-scavenging agents inside transgenic bacteria for subsequent retrieval. So far, this approach has produced limited protection and accumulation. We report here the development of a transgenic system that effectively expresses metallothionein (mt-1) and polyphosphate kinase (ppk) genes in bacteria in order to provide high mercury resistance and accumulation. Results In this study, bacterial transformation with transcriptional and translational enhanced vectors designed for the expression of metallothionein and polyphosphate kinase provided high transgene transcript levels independent of the gene being expressed. Expression of polyphosphate kinase and metallothionein in transgenic bacteria provided high resistance to mercury, up to 80 μM and 120 μM, respectively. Here we show for the first time that metallothionein can be efficiently expressed in bacteria without being fused to a carrier protein to enhance mercury bioremediation. Cold vapor atomic absorption spectrometry analyzes revealed that the mt-1 transgenic bacteria accumulated up to 100.2 ± 17.6 μM of mercury from media containing 120 μM Hg. The extent of mercury remediation was such that the contaminated media remediated by the mt-1 transgenic bacteria supported the growth of untransformed bacteria. Cell aggregation, precipitation and color changes were visually observed in mt-1 and ppk transgenic bacteria when these cells were grown in high mercury concentrations. Conclusion The transgenic bacterial system described in this study presents a viable technology for mercury bioremediation from liquid matrices because it provides high mercury resistance and accumulation while inhibiting elemental mercury volatilization. This is the first report that shows that metallothionein expression provides mercury resistance and accumulation in recombinant bacteria

Relationship of /sup 65/Zn absorption kinetics to intestinal metallothionein in rats: effects of zinc depletion and fasting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoadley, J.E.; Leinart, A.S.; Cousins, R.J.

1988-04-01

Intestinal 65Zn transport and metallothionein levels were examined in rats fed zinc-adequate and zinc-deficient diets and in rats subjected to an overnight fast. 65Zn uptake by intestines perfused with 1.5 microM 65Zn was greater in both zinc-deficient and fasted groups than in the control group. Mucosal retention of 65Zn was also greater in the zinc-deficient group but not in the fasted group. The greater 65Zn uptake in the fasted group was associated with a compartment that readily released 65Zn back into the lumen. Kinetic analysis of the rate of 65Zn transfer to the vascular space (absorption) showed that 65Zn absorptionmore » involved approximately 3% of mucosal 65Zn in a 40-min perfusion period. The half-life (t1/2) of this mucosal 65Zn rapid transport pool corresponded directly to changes in intestinal metallothionein levels. Both metallothionein and t1/2 were higher in the fasted group and lower in the zinc-deficient group than in controls. While the rate of 65Zn transport from this rapid transport pool decreased with increasing metallothionein level, the predicted pool size increased when the metallothionein level was elevated by fasting. These results indicate that the rate of zinc absorption is inversely related to intestinal metallothionein levels, but the portion of mucosal 65Zn available for absorption is directly related to intestinal metallothionein.« less

Metallothionein induction in aquatic oligochaete tubifex tubifex exposed to herbicide isoproturon.

PubMed

Mosleh, Y Y; Paris-Palacios, S; Arnoult, F; Couderchet, M; Biagianti-Risbourg, S; Vernet, G

2004-02-01

Metallothioneins (MTs) are low-molecular-weight proteins mainly involved in metal ion detoxification. Recently it has been demonstrated that MTs participate in several cellular functions such as regulation of growth and antioxidative defenses. Moreover, pesticides can induce their synthesis. The aim of the current work was to determine the effects of isoproturon, either pure or formulated as Matin (suspension containing an isoproturon concentration of 500 g. L(-1)), on the metallothionein and total protein contents of the aquatic worm Tubifex tubifex. MT levels in exposed worms increased significantly after 7 and 15 days of exposure to a concentration of the herbicide of 50 mg. L(-1). Isoproturon reduced the metal (Cu, Zn, and Cd) content of metallothioneins, and it also increased the total protein content of the worms. These results suggest that MT induction may not be considered a specific biomarker of metal exposure but that it can be used as a nonspecific biomarker of the effect of isoproturon effect in aquatic worms. Copyright 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 88-93, 2004.

Roles of zinc and metallothionein-3 in oxidative stress-induced lysosomal dysfunction, cell death, and autophagy in neurons and astrocytes.

PubMed

Lee, Sook-Jeong; Koh, Jae-Young

2010-10-26

Zinc dyshomeostasis has been recognized as an important mechanism for cell death in acute brain injury. An increase in the level of free or histochemically reactive zinc in astrocytes and neurons is considered one of the major causes of death of these cells in ischemia and trauma. Although zinc dyshomeostasis can lead to cell death via diverse routes, the major pathway appears to involve oxidative stress.Recently, we found that a rise of zinc in autophagic vacuoles, including autolysosomes, is a prerequisite for lysosomal membrane permeabilization and cell death in cultured brain cells exposed to oxidative stress conditions. The source of zinc in this process is likely redox-sensitive zinc-binding proteins such as metallothioneins, which release zinc under oxidative conditions. Of the metallothioneins, metallothionein-3 is especially enriched in the central nervous system, but its physiologic role in this tissue is not well established. Like other metallothioneins, metallothionein-3 may function as metal detoxicant, but is also known to inhibit neurite outgrowth and, sometimes, promote neuronal death, likely by serving as a source of toxic zinc release. In addition, metallothionein-3 regulates lysosomal functions. In the absence of metallothionein-3, there are changes in lysosome-associated membrane protein-1 and -2, and reductions in certain lysosomal enzymes that result in decreased autophagic flux. This may have dual effects on cell survival. In acute oxidative injury, zinc dyshomeostasis and lysosomal membrane permeabilization are diminished in metallothionein-3 null cells, resulting in less cell death. But over the longer term, diminished lysosomal function may lead to the accumulation of abnormal proteins and cause cytotoxicity.The roles of zinc and metallothionein-3 in autophagy and/or lysosomal function have just begun to be investigated. In light of evidence that autophagy and lysosomes may play significant roles in the pathogenesis of various neurological

Variation of Metallothionein I and II Gene Expression in the Bank Vole (Clethrionomys glareolus) Under Environmental Zinc and Cadmium Exposure.

PubMed

Mikowska, Magdalena; Dziublińska, Barbara; Świergosz-Kowalewska, Renata

2018-07-01

The main idea of the study was to assess how environmental metal pollution activates defence responses at transcription levels in the tissues of bank voles (Clethrionomys glareolus). For this purpose, the metallothioneine (MT) genes expression (a well known biomarker of exposure and response to various metals) was measured. The real-time PCR method was used for relative quantification of metallothionein I and metallothionein II expressions in the livers, kidneys and testes of bank voles from six populations exposed to different contaminants, mainly zinc, cadmium and iron. The assessment of Zn, Cu and Fe concentrations in the tissues allowed to study the MTs gene expression responses to these metals. ANOVA analysis showed differences between populations in terms of metal concentration in tissues, livers and kidneys. Student T test showed significant differences in metal concentration between unpolluted and polluted sites only for the liver tissue: significantly lower Zn levels and significantly higher Fe levels in the unpolluted sites. Kruskal-Wallis test performed on C T data shows differences in the gene expressions between populations for both MT genes for liver and testes. In the liver metallothionein I gene expression was upregulated in populations considered as more polluted (up to 7.5 higher expression in Miasteczko Śląskie comparing to Mikołajki). Expression of metallothionein II revealed a similar pattern. In kidneys, differences in expression of both MT genes were not that evident. In testes, MT upregulation in polluted sites was noted for metallothionein II. For metallothionein however, we found downregulation in populations from more contaminated sites. The expressions of both MTs were positively influenced by cadmium in kidney (concentration data from the previous study) and zinc and copper in liver, while cadmium had effects only on the liver MT II gene expression. Positive relationship was obtained for lead and metallothionein II expression in the

Review on methods for determination of metallothioneins in aquatic organisms.

PubMed

Shariati, Fatemeh; Shariati, Shahab

2011-06-01

One aspect of environmental degradation in coastal areas is pollution from toxic metals, which are persistent and are bioaccumulated by marine organisms, with serious public health implications. A conventional monitoring system of environmental metal pollution includes measuring the level of selected metals in the whole organism or in respective organs. However, measuring only the metal content in particular organs does not give information about its effect at the subcellular level. Therefore, the evaluation of biochemical biomarker metallothionein may be useful in assessing metal exposure and the prediction of potential detrimental effects induced by metal contamination. There are some methods for the determination of metallothioneins including spectrophotometric method, electrochemical methods, chromatography, saturation-based methods, immunological methods, electrophoresis, and RT-PCR. In this paper, different methods are discussed briefly and the comparison between them will be presented.

The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sato, Shoko, E-mail: satosho@rs.tus.ac.jp; Shirakawa, Hitoshi, E-mail: shirakah@m.tohoku.ac.jp; Tomita, Shuhei, E-mail: tomita@med.tottori-u.ac.jp

2013-11-15

Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHRmore » or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction.« less

THE EMBRYOLETHALITY OF LIPOPOLYSACCHARIDE IN CD-1 AND METALLOTHIONEIN I-II NULL MICE: LACK OF A ROLE FOR INDUCED ZINC DEFICIENCY OR METALLOTHIONEIN INDUCTION

EPA Science Inventory

ABSTRACT

Lipopolysaccharide (LPS) is embryolethal in CD-1 mice. LPS induces metallothionein (MT) via cytokines, including TNF-, IL-1 and IL-6, which initiate and maintain the acute phase response. Maternal hepatic MT induction in pregnant rats, by diverse toxicants, can ...

Copper metallothioneins.

PubMed

Calvo, Jenifer; Jung, Hunmin; Meloni, Gabriele

2017-04-01

Metallothioneins (MTs) are a class of low molecular weight and cysteine-rich metal binding proteins present in all the branches of the tree of life. MTs efficiently bind with high affinity several essential and toxic divalent and monovalent transition metals by forming characteristic polynuclear metal-thiolate clusters within their structure. MTs fulfil multiple biological functions related to their metal binding properties, with essential roles in both Zn(II) and Cu(I) homeostasis as well as metal detoxification. Depending on the organism considered, the primary sequence, and the specific physiological and metabolic status, Cu(I)-bound MT isoforms have been isolated, and their chemistry and biology characterized. Besides the recognized role in the biochemistry of divalent metals, it is becoming evident that unique biological functions in selectively controlling copper levels, its reactivity as well as copper-mediated biochemical processes have evolved in some members of the MT superfamily. Selected examples are reviewed to highlight the peculiar chemical properties and biological functions of copper MTs. © 2016 IUBMB Life, 69(4):236-245, 2017. © 2017 International Union of Biochemistry and Molecular Biology.

Metallothionein blocks oxidative DNA damage induced by acute inorganic arsenic exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu, Wei, E-mail: qu@niehs.nih.gov; Waalkes, Michael P.

We studied how protein metallothionein (MT) impacts arsenic-induced oxidative DNA damage (ODD) using cells that poorly express MT (MT-I/II double knockout embryonic cells; called MT-null cells) and wild-type (WT) MT competent cells. Arsenic (as NaAsO{sub 2}) was less cytolethal over 24 h in WT cells (LC{sub 50} = 11.0 ± 1.3 μM; mean ± SEM) than in MT-null cells (LC{sub 50} = 5.6 ± 1.2 μM). ODD was measured by the immuno-spin trapping method. Arsenic (1 or 5 μM; 24 h) induced much less ODD in WT cells (121% and 141% of control, respectively) than in MT-null cells (202% andmore » 260%). In WT cells arsenic caused concentration-dependent increases in MT expression (transcript and protein), and in the metal-responsive transcription factor-1 (MTF-1), which is required to induce the MT gene. In contrast, basal MT levels were not detectable in MT-null cells and unaltered by arsenic exposure. Transfection of MT-I gene into the MT-null cells markedly reduced arsenic-induced ODD levels. The transport genes, Abcc1 and Abcc2 were increased by arsenic in WT cells but either showed no or very limited increases in MT-null cells. Arsenic caused increases in oxidant stress defense genes HO-1 and GSTα2 in both WT and MT-null cells, but to much higher levels in WT cells. WT cells appear more adept at activating metal transport systems and oxidant response genes, although the role of MT in these responses is unclear. Overall, MT protects against arsenic-induced ODD in MT competent cells by potential sequestration of scavenging oxidant radicals and/or arsenic. - Highlights: • Metallothionein blocks arsenic toxicity. • Metallothionein reduces arsenic-induced DNA damage. • Metallothionein may bind arsenic or radicals produced by arsenic.« less

Transcription patterns of genes encoding four metallothionein homologs in Daphnia pulex exposed to copper and cadmium are time- and homolog- dependent

PubMed Central

Asselman, Jana; Shaw, Joseph R.; Glaholt, Stephen P.; Colbourne, John K.; De Schamphelaere, Karel AC.

2013-01-01

Metallothioneins are proteins that play an essential role in metal homeostasis and detoxification in nearly all organisms studied to date. Yet discrepancies between outcomes of chronic and acute exposure experiments hamper the understanding of the regulatory mechanisms of their isoforms following metal exposure. Here, we investigated transcriptional differences among four identified homologs (mt1–mt4) in Daphnia pulex exposed across time to copper and cadmium relative to a control. Transcriptional upregulation of mt1 and mt3 was detected on day four following exposure to cadmium, whereas that of mt2 and mt4 was detected on day two and day eight following exposure to copper. These results confirm temporal and metal-specific differences in the transcriptional induction of genes encoding metallothionein homologs upon metal exposure which should be considered in ecotoxicological monitoring programs of metal-contaminated water bodies. Indeed, the mRNA expression patterns observed here illustrate the complex regulatory system associated with metallothioneins, as these patterns are not only dependent on the metal, but also on exposure time and the homolog studied. Further phylogenetic analysis and analysis of regulatory elements in upstream promoter regions revealed a high degree of similarity between metallothionein genes of Daphnia pulex and Daphnia magna, a species belonging to the same genus. These findings, combined with a limited amount of available expression data for D. magna metallothionein genes, tentatively suggest a potential generalization of the metallothionein response system between these Daphnia species. PMID:24113165

Multiscale digital Arabidopsis predicts individual organ and whole-organism growth.

PubMed

Chew, Yin Hoon; Wenden, Bénédicte; Flis, Anna; Mengin, Virginie; Taylor, Jasper; Davey, Christopher L; Tindal, Christopher; Thomas, Howard; Ougham, Helen J; de Reffye, Philippe; Stitt, Mark; Williams, Mathew; Muetzelfeldt, Robert; Halliday, Karen J; Millar, Andrew J

2014-09-30

Understanding how dynamic molecular networks affect whole-organism physiology, analogous to mapping genotype to phenotype, remains a key challenge in biology. Quantitative models that represent processes at multiple scales and link understanding from several research domains can help to tackle this problem. Such integrated models are more common in crop science and ecophysiology than in the research communities that elucidate molecular networks. Several laboratories have modeled particular aspects of growth in Arabidopsis thaliana, but it was unclear whether these existing models could productively be combined. We test this approach by constructing a multiscale model of Arabidopsis rosette growth. Four existing models were integrated with minimal parameter modification (leaf water content and one flowering parameter used measured data). The resulting framework model links genetic regulation and biochemical dynamics to events at the organ and whole-plant levels, helping to understand the combined effects of endogenous and environmental regulators on Arabidopsis growth. The framework model was validated and tested with metabolic, physiological, and biomass data from two laboratories, for five photoperiods, three accessions, and a transgenic line, highlighting the plasticity of plant growth strategies. The model was extended to include stochastic development. Model simulations gave insight into the developmental control of leaf production and provided a quantitative explanation for the pleiotropic developmental phenotype caused by overexpression of miR156, which was an open question. Modular, multiscale models, assembling knowledge from systems biology to ecophysiology, will help to understand and to engineer plant behavior from the genome to the field.

Quantitative immunodetection of metallothioneins in relation to metals concentration in spiders from variously polluted areas.

PubMed

Babczyńska, Agnieszka; Wilczek, Grażyna; Szulińska, Elżbieta; Franiel, Izabella

2011-09-01

Spiders inhabiting post industrial environments, such as waste heaps or ore-bearing areas, are exposed to high concentrations of metals, accumulated in the body of their prey and transferred along food chains. Therefore spiders are pressed to develop metal-neutralization strategies. Low-molecular, multifunction proteins: metallothioneins (MTs), often postulated as biomarkers of metal exposure, are known to bind metals and thus protect organisms against their toxic effects. Yet the proteins are still not well recognized in spiders. The aim of this study was to assess, by immunodetection method, ELISA, the concentration of metallothioneins in adult females of three web building spider species: Araneus diadematus (Araneidae), Agelena labyrinthica (Agelenidae) and Linyphia triangularis (Linyphiidae) from three variously polluted areas in southern Poland: Olkusz, ore-bearing post industrial site; Katowice-WeŁnowiec: post metallurgic waste heap, Pilica: the reference, rural, area. The concentration of metallothioneins has been analyzed in relation to the metal concentration in spiders body. The study gives the evidence that metallothioneins are reliably detectable by means of ELISA technique. The analysis of results obtained shows a strong species-dependence of the MTs level. Positive correlations between MTs concentration and metal body burden (mainly Zn and Pb) were found. This suggests that the proteins play an important role in the neutralization and regulation of metal ions in spiders. The same correlation indicate the possibility to consider MTs in spiders as biomarkers of metal exposure and effects. However, the species specificity as well as metal characteristics should be taken under account. Copyright © 2011 Elsevier Inc. All rights reserved.

Modulation of nitric oxide-mediated metal release from metallothionein by the redox state of glutathione in vitro.

PubMed

Khatai, Leila; Goessler, Walter; Lorencova, Helena; Zangger, Klaus

2004-06-01

Metallothioneins (MTs) release bound metals when exposed to nitric oxide. At inflammatory sites, both metallothionein and inducible nitric oxide synthase (iNOS) are induced by the same factors and the zinc released from metallothionein by NO suppresses both the induction and activity of iNOS. In a search for a possible modulatory mechanism of this coexpression of counteracting proteins, we investigated the role of the glutathione redox state in vitro because the oxidation state of thiols is involved in the metal binding in Cd-S or Zn-S clusters found in metallothioneins, and NO also binds to reduced glutathione via S-nitrosation. Using a variety of techniques, we found that NO and also ONOO(-)-mediated metal release from purified MTs is suppressed by reduced glutathione (GSH), but not by oxidized glutathione. Considering the millimolar concentrations of GSH present in mammalian cells, the metal release from MTs by NO should play no role in living systems. Therefore, the fact that it has been observed in vivo points to a hitherto unknown mechanism or additional compound(s) being involved in this physiologically relevant reaction and as long as this additional factor is not found experimental results on the MT-NO interaction should be treated with caution. Contrary to the peroxynitrite-induced activation of guanylyl cyclase, where GSH is needed, we found that the metal release from metallothionein by peroxynitrite is not enhanced, but also suppressed by reduced glutathione. In addition, we show that zinc, the major natural metal ligand in mammalian MTs and suppressor of iNOS, is released more readily under the influence of NO than cadmium, but in contrast to the MT isoform 1, the amount of metal released from the beta-domain of MT-2 is comparable to that from the alpha-domain.

Partial contribution of the Keap1–Nrf2 system to cadmium-mediated metallothionein expression in vascular endothelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shinkai, Yasuhiro; Kimura, Tomoki; Itagaki, Ayaka

Cadmium is an environmental electrophile that modifies protein reactive thiols such as Kelch-like ECH-associated protein 1 (Keap1), a negative regulator of nuclear factor-erythroid 2-related factor 2 (Nrf2). In the present study, we investigated a role of the Keap1–Nrf2 system in cellular response to cadmium in vascular endothelial cells. Exposure of bovine aortic endothelial cells to cadmium resulted in modification of Keap1 and Nrf2 activation, thereby up-regulating not only its typical downstream proteins but also metallothionein-1/2. Experiments with siRNA-mediated knockdown of Nrf2 or Keap1 supported participation of the Keap1–Nrf2 system in the modulation of metallothionein-1/2 expression. Furthermore, chromatin immunoprecipitation assay showedmore » that Nrf2 was recruited to the antioxidant response element of the promoter region of the bovine metallothionein-2 gene in the presence of cadmium. These results suggest that the transcription factor Nrf2 plays, at least in part, a role in the changes in metallothionein expression mediated by exposure to cadmium. - Highlights: • Role of the Keap1–Nrf2 system in cellular response to cadmium was examined. • We used bovine aortic endothelial cells as a model of the vascular endothelium. • Exposure of cells to cadmium resulted in modification of Keap1 and Nrf2 activation. • Keap1–Nrf2 system participated in the modulation of metallothionein-1/2 expression. • Nrf2 was recruited to the antioxidant response element of MT2 promoter region.« less

Metallothionein Gene Duplications and Metal Tolerance in Natural Populations of Drosophila melanogaster

PubMed Central

Maroni, G.; Wise, J.; Young, J. E.; Otto, E.

1987-01-01

A search for duplications of the Drosophila melanogaster metallothionein gene (Mtn) yielded numerous examples of this type of chromosomal rearrangement. These duplications are distributed widely—we found them in samples from four continents, and they are functional—larvae carrying Mtn duplications produce more Mtn RNA and tolerate increased cadmium and copper concentrations. Six different duplication types were characterized by restriction-enzyme analyses using probes from the Mtn region. The restriction maps show that in four cases the sequences, ranging in size between 2.2 and 6.0 kb, are arranged as direct, tandem repeats; in two other cases, this basic pattern is modified by the insertion of a putative transposable element into one of the repeated units. Duplications of the D. melanogaster metallothionein gene such as those that we found in natural populations may represent early stages in the evolution of a gene family. PMID:2828157

Evaluation of cadmium, lead and metallothionein contents in the tissues of mussels (Mytilus galloprovincialis) from the Campania coast (Italy): levels and seasonal trends.

PubMed

Scudiero, Rosaria; Cretì, Patrizia; Trinchella, Francesca; Grazia Esposito, Maria

2014-01-01

The biological effect of seasonality on cadmium, lead and metallothionein contents was assessed in mussels Mytilus galloprovincialis from natural banks located along the coastline of the Gulf of Naples (Campania, Italy). Heavy metals and metallothionein concentrations were measured in digestive and reproductive glands. The results showed a clear correlation between metallothionein content and the reproductive gland status determined during the seasons; on the contrary, no correlation was found between metallothionein and metal contents. Data allow us to hypothesize that metallothionein functions go beyond metal detoxification, thus opening new scenarios for these proteins in invertebrates. The effect of seasons on metals concentration in mussel tissues showed similar seasonal patterns between the sites, regardless of their anthropogenic impacts. Cadmium content was not strictly related to seasonal periods, whereas lead content was significantly lower in summer. The results also indicate that the metal contents in mussels from the Gulf of Naples do not represent a risk to human health, even in the period of their maximum accumulation, and that the relaying of mussels before marketing could improve the animal stress conditions, but having a slight effect on metal excretion. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

A High-Throughput Arabidopsis Reverse Genetics System

PubMed Central

Sessions, Allen; Burke, Ellen; Presting, Gernot; Aux, George; McElver, John; Patton, David; Dietrich, Bob; Ho, Patrick; Bacwaden, Johana; Ko, Cynthia; Clarke, Joseph D.; Cotton, David; Bullis, David; Snell, Jennifer; Miguel, Trini; Hutchison, Don; Kimmerly, Bill; Mitzel, Theresa; Katagiri, Fumiaki; Glazebrook, Jane; Law, Marc; Goff, Stephen A.

2002-01-01

A collection of Arabidopsis lines with T-DNA insertions in known sites was generated to increase the efficiency of functional genomics. A high-throughput modified thermal asymetric interlaced (TAIL)-PCR protocol was developed and used to amplify DNA fragments flanking the T-DNA left borders from ∼100,000 transformed lines. A total of 85,108 TAIL-PCR products from 52,964 T-DNA lines were sequenced and compared with the Arabidopsis genome to determine the positions of T-DNAs in each line. Predicted T-DNA insertion sites, when mapped, showed a bias against predicted coding sequences. Predicted insertion mutations in genes of interest can be identified using Arabidopsis Gene Index name searches or by BLAST (Basic Local Alignment Search Tool) search. Insertions can be confirmed by simple PCR assays on individual lines. Predicted insertions were confirmed in 257 of 340 lines tested (76%). This resource has been named SAIL (Syngenta Arabidopsis Insertion Library) and is available to the scientific community at www.tmri.org. PMID:12468722

The transcription factor MTF-1 is essential for basal and heavy metal-induced metallothionein gene expression.

PubMed

Heuchel, R; Radtke, F; Georgiev, O; Stark, G; Aguet, M; Schaffner, W

1994-06-15

We have described and cloned previously a factor (MTF-1) that binds specifically to heavy metal-responsive DNA sequence elements in the enhancer/promoter region of metallothionein genes. MTF-1 is a protein of 72.5 kDa that contains six zinc fingers and multiple domains for transcriptional activation. Here we report the disruption of both alleles of the MTF-1 gene in mouse embryonic stem cells by homologous recombination. The resulting null mutant cell line fails to produce detectable amounts of MTF-1. Moreover, due to the loss of MTF-1, the endogenous metallothionein I and II genes are silent, indicating that MTF-1 is required for both their basal and zinc-induced transcription. In addition to zinc, other heavy metals, including cadmium, copper, nickel and lead, also fail to activate metal-responsive promoters in null mutant cells. However, cotransfection of an MTF-1 expression vector and metal-responsive reporter genes yields strong basal transcription that can be further boosted by zinc treatment of cells. These results demonstrate that MTF-1 is essential for metallothionein gene regulation. Finally, we present evidence that MTF-1 itself is a zinc sensor, which exhibits increased DNA binding activity upon zinc treatment.

Changes in Metallothionein Level in Rat Hepatic Tissue after Administration of Natural Mouldy Wheat

PubMed Central

Vasatkova, Anna; Krizova, Sarka; Adam, Vojtech; Zeman, Ladislav; Kizek, Rene

2009-01-01

Mycotoxins are secondary metabolites produced by microfungi that are capable of causing disease and death in humans and other animals. This work was aimed at investigation of influence of mouldy wheat contaminated by pathogenic fungi producing mycotoxins on metallothionein levels in hepatic tissue of rats. The rats were administrating feed mixtures with different contents of vitamins or naturally mouldy wheat for 28 days. It was found that the wheat contained deoxynivalenol (80 ± 5 μg per kg of mouldy wheat), zearalenone (56 ± 3 μg/kg), T2-toxin (20 ± 2 μg/kg) and aflatoxins as a sum of B1, B2, G1 and G2 (3.9 ± 0.2 μg/kg). Rats were fed diets containing 0, 33, 66 and 100% naturally moulded wheat. Control group 0, 33, 66 and 100% contained vitamins according to Nutrient Requirements of Rats (NRC). Other four groups (control group with vitamins, vit33, vit66 and vit100%) were fed on the same levels of mouldy wheat, also vitamins at levels 100% higher than the previous mixtures. We determined weight, feed conversion and performed dissection to observe pathological processes. Changes between control group and experimental groups exposed to influence of mouldy wheat and experimental groups supplemented by higher concentration of vitamins and mouldy wheat were not observed. Livers were sampled and did not demonstrate significant changes in morphology compared to control either. In the following experiments the levels of metallothionein as a marker of oxidative stress was determined. We observed a quite surprising trend in metallothionein levels in animals supplemented with increased concentration of vitamins. Its level enhanced with increasing content of mouldy wheat. It was possible to determine a statistically significant decline (p<0.05) between control group and groups of animals fed with 33, 66 and 100% mouldy wheat. It is likely that some mycotoxins presented in mouldy wheat are able to block the mechanism of metallothionein synthesis. PMID:19399242

Immunohistochemical expression of metallothionein in normal human colorectal mucosa, in adenomas and in adenocarcinomas and their associated metastases.

PubMed

Giuffrè, G; Barresi, G; Sturniolo, G C; Sarnelli, R; D'Incà, R; Tuccari, G

1996-10-01

The immunohistochemical distribution pattern of metallothionein, a low molecular weight protein with strong affinity for divalent heavy metal ions, has been investigated in normal and neoplastic conditions of the large bowel. Utilizing a monoclonal mouse antibody the following formalin-fixed paraffin-embedded surgical or biopsy samples were studied: tubulo-villous adenomas (8 cases); adenocarcinomas with various degree of differentiation (85), nine of which were mucinous-type; synchronous tubular or tubulo-villous adenomas separate from carcinomas (30); transitional mucosa (45); metastases in lymph nodes (43); and distant metastases (45). Twenty biopsies from the right and left colon of 10 patients affected by irritable bowel syndrome were also analyzed. Normal colonic mucosa as well as transitional mucosa showed metallothionein immunopositivity in enterocytes at the luminal surface and crypts. Evident nuclear and cytoplasmic staining was encountered in tubulo-villous adenomas; the same reactivity was noted in the basal glandular component of colorectal carcinomas-synchronous adenomas, while less intense staining was noted in the apical villous portions. A variable metallothionein immunostaining was observed in adenocarcinomas (62.3%), in lymph node (55.8%) and distant hepatic (17.2%) and omental (43.8%) metastases, although it was not always concordant with that reported in the corresponding primary tumour. Whether the metallothionein positivity observed in normal and neoplastic cells is the result of expression of a stable form of the protein or an accumulation in the nucleus and cytoplasm remains to be clarified.

Cardiac-specific overexpression of metallothionein attenuates myocardial remodeling and contractile dysfunction in l-NAME-induced experimental hypertension: Role of autophagy regulation.

PubMed

Yang, Lifang; Gao, Jian-Yuan; Ma, Jipeng; Xu, Xihui; Wang, Qiurong; Xiong, Lize; Yang, Jian; Ren, Jun

2015-09-02

Hypertension is an independent risk factor for heart disease and is responsible for the increased cardiac morbidity and mortality. Oxidative stress plays a key role in hypertensive heart diseases although the precise mechanism remains unclear. This study was designed to examine the effect of cardiac-specific overexpression of metallothionein, a cysteine-rich antioxidant, on myocardial contractile and intracellular Ca(2+) anomalies in N(G)-nitro-l-arginine methyl ester (l-NAME)-induced experimental hypertension and the mechanism involved with a focus on autophagy. Our results revealed that l-NAME treatment (14 days) led to hypertension and myocardial anomalies evidenced by interstitial fibrosis, cardiomyocyte hypertrophy, increased LV end systolic and diastolic diameters (LVESD and LVEDD) along with suppressed fractional shortening. l-NAME compromised cardiomyocyte contractile and intracellular Ca(2+) properties manifested as depressed peak shortening, maximal velocity of shortening/relengthening, electrically-stimulated rise in intracellular Ca(2+), elevated baseline and peak intracellular Ca(2+). These l-NAME-induced histological and mechanical changes were attenuated or reconciled by metallothionein. Protein levels of autophagy markers LC3B and p62 were decreased and increased, respectively. Autophagy signaling molecules AMPK, TSC2 and ULK1 were inactivated while those of mTOR and p70s6K were activated by l-NAME, the effects of which were ablated by metallothionein. Autophagy induction mimicked whereas autophagy inhibition nullified the beneficial effect of metallothionein against l-NAME. These findings suggested that metallothionein protects against l-NAME-induced myocardial anomalies possibly through restoration of autophagy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The potential effect of metallothionein 2A - 5 A/G single nucleotide polymorphism on blood cadmium, lead, zinc and copper levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kayaalti, Zeliha, E-mail: kayaalti@ankara.edu.tr; Aliyev, Vugar; Soeylemezoglu, Tuelin

2011-10-01

Metallothioneins (MTs) are low molecular weight, cysteine-rich, metal-binding proteins. Because of their rich thiol groups, MTs bind to the biologically essential metals and perform these metals' homeostatic regulations; absorb the heavy metals and assist with their transportation and extraction. The aim of this study was to investigate the association between the metallothionein 2A (MT2A) core promoter region - 5 A/G single nucleotide polymorphism (SNP) and Cd, Pb, Zn and Cu levels in the blood samples. MT2A polymorphism was determined by the standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique using the 616 blood samples and the genotype frequencies weremore » found as 86.6% homozygote typical (AA), 12.8% heterozygote (AG) and 0.6% homozygote atypical (GG). Metal levels were analyzed by dual atomic absorption spectrophotometer system and the average levels of Cd, Pb, Zn and Cu in the blood samples were 1.69 {+-} 1.57 ppb, 30.62 {+-} 14.13 ppb, 0.98 {+-} 0.49 ppm and 1.04 {+-} 0.45 ppm, respectively. As a result; highly statistically significant associations were detected between the - 5 A/G core promoter region SNP in the MT2A gene and Cd, Pb and Zn levels (p = 0.004, p = 0.012 and p = 0.002, respectively), but no association was found with Cu level (p = 0.595). Individuals with the GG genotype had statistically lower Zn level and higher Cd and Pb levels in the blood samples than individuals with AA and AG genotypes. This study suggests that having the GG genotype individuals may be more sensitive for the metal toxicity and they should be more careful about protecting their health against the toxic effects of the heavy metals. - Highlights: > MT2A -5A/G SNP has strong effect on the Cd, Pb and Zn levels in the blood. > MT2A GG individuals should be more careful for their health against metal toxicity. > This SNP might be considered as a biomarker for risk of disease related to metals.« less

Expression of metallothionein and α-tubulin in heavy metal-tolerant Anopheles gambiae sensu stricto (Diptera: Culicidae)

PubMed Central

Mireji, Paul O.; Keating, Joseph; Hassanali, Ahmed; Impoinvil, Daniel E.; Mbogo, Charles M.; Njeri, Martha; Nyambaka, Hudson; Kenya, Eucharia; Githure, John I; Beier, John C.

2009-01-01

Anopheles mosquitoes have been shown to adapt to heavy metals in their natural habitats. In this study we explored the possibility of using Anopheles gambiae sensu stricto as bio-reporters for environmental heavy metal pollution through expressions of their metal responsive metallothionein and α-tubulin genes. The study was undertaken with third instar larvae after selection by cadmium, copper, or lead at LC30 through five successive generations. Expression levels were determined in the fifth generation by semi quantitative RT-PCR on the experimental and control populations. The data were analyzed using one-way ANOVA. The highest metallothionein (F3, 11= 4.574, P = 0.038) and α-tubulin (F3,11= 12.961, P = 0.002) responses were observed in cadmium-tolerant treatments. There was significantly higher expression of metallothionein in cadmium or copper treatments relative to the control (P = 0.012), and in cadmium than in lead treatments (P = 0.044). Expressions of α-tubulin were significantly higher in cadmium than in control treatments (P = 0.008). These results demonstrate capacity of An. gambiae s.s. to develop tolerance to increased levels of heavy metal challenge. The results also confirm the potential of heavy metal responsive genes in mosquitoes as possible bio-indicators of heavy metal environmental pollution. How the tolerance and expressions relate to An. gambiae s.s. fitness and vectorial capacity in the environment remains to be elucidated. PMID:19735939

Metallothionein--a promising tool for cancer diagnostics.

PubMed

Krizkova, S; Fabrik, I; Adam, V; Hrabeta, J; Eckschlager, T; Kizek, R

2009-01-01

The latest research outcomes indicate that metallothionein (MT) levels in peripheral blood and serum from cancer patients can provide many interesting information about type or clinical stage of the disease, or response to therapy. MT plays a key role in transport of essential heavy metals, detoxification of toxic metals and protection of cells against oxidation stress. Serum MT levels of cancer patients are three times higher than control patients (0.5 microM). The elevated MT levels in cancer cells are probably related to their increased proliferation and protection against apoptosis. Automated electrochemical detection of MT allows its serial analysis in a very small volume with excellent sensitivity, reliability and reproducibility and therefore it can be considered as a new tool for cancer diagnosis (Fig. 4, Ref. 55). Full Text (Free, PDF) www.bmj.sk.

Mammalian Metallothionein-2A and Oxidative Stress

PubMed Central

Ling, Xue-Bin; Wei, Hong-Wei; Wang, Jun; Kong, Yue-Qiong; Wu, Yu-You; Guo, Jun-Li; Li, Tian-Fa; Li, Ji-Ke

2016-01-01

Mammalian metallothionein-2A (MT2A) has received considerable attention in recent years due to its crucial pathophysiological role in anti-oxidant, anti-apoptosis, detoxification and anti-inflammation. For many years, most studies evaluating the effects of MT2A have focused on reactive oxygen species (ROS), as second messengers that lead to oxidative stress injury of cells and tissues. Recent studies have highlighted that oxidative stress could activate mitogen-activated protein kinases (MAPKs), and MT2A, as a mediator of MAPKs, to regulate the pathogenesis of various diseases. However, the molecule mechanism of MT2A remains elusive. A deeper understanding of the functional, biochemical and molecular characteristics of MT2A would be identified, in order to bring new opportunities for oxidative stress therapy. PMID:27608012

Cadium pathways during gestation and lactation in control vs. metallothionein 1,2-knockout mice.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brako, E. E.; Wilson, A. K.; Jonah, M. M.

2003-01-01

Effects of metallothionein (MT) on cadmium absorption and transfer pathways during gestation and lactation in mice were investigated. Female 129/SvJ metallothionein-knockout (MT1,2KO) and metallothionein-normal (MTN) mice received drinking water containing trace amounts of {sup 109}CdCl{sub 2} (0.15 ng Cd/ml; 0.074 {mu}Ci {sup 109}Cd/ml). {sup 109}Cd and MT in maternal, fetal, and pup tissues were measured on gestation days 7, 14, and 17 and lactation day 11. In dams, MT influenced both the amount of {sup 109}Cd transferred from intestine into body (two- to three-fold higher in MT1,2KO than MTN dams) and tissue-specific {sup 109}Cd distribution (higher liver/kidney ratio in MT1,2KOmore » dams). Placental {sup 109}Cd concentrations in MT1,2KO dams were three- and seven-fold higher on gestation days 14 and 17, respectively, than in MTN dams. Fetal {sup 109}Cd levels were low in both mouse types, but at least 10-fold lower in MTN fetuses. MT had no effect on the amount of {sup 109}Cd transferred to pups via milk; furthermore, 85--90% of total pup {sup 109}Cd was recovered in gastrointestinal tracts of both types, despite high duodenal MT only in MTN pups. A relatively large percentage of milk-derived intestinal {sup 109}Cd was transferred to other pup tissues in both MT1,2KO and MTN pups (14 and 10%, respectively). These results demonstrate that specific sequestration of cadmium by both maternal and neonatal intestinal tract does not require MT. Although MT decreased oral cadmium transfer from intestine to body tissues at low cadmium exposure levels, MT did not play a major role in restricting transfer of cadmium from dam to fetus via placenta and to neonate via milk.« less

Metallothionein expression in canine and feline mammary and melanotic tumours.

PubMed

Dincer, Z; Jasani, B; Haywood, S; Mullins, J E; Fuentealba, I C

2001-01-01

Moderate to strong immunohistochemical metallothionein (MT) positivity (MT expression) is associated with a poor prognosis in some human tumours. The aim of this study was to determine MT expression in mammary tumours and cutaneous melanomas in dogs and cats. Canine (67) and feline (47) mammary tumours, and cutaneous melanomas (canine 40, feline 26) were immunolabelled with MT monoclonal antibody E9. The overall incidence of MT expression of these tumours was similar to that observed in various human neoplasms. However, a striking interspecies difference was detected. In dogs, MT expression occurred in 100% of benign and 57% of malignant mammary tumours. In cats, however, 30% of malignant mammary tumours expressed MT but benign mammary tumours and cases of fibroadenomatous hyperplasia did not. Moderate to strong MT immunoreactivity was detected in 30% of benign and 25% of malignant cutaneous melanomas in dogs, and in 6% of malignant melanomas in cats. The findings in feline mammary tumours resembled findings reported in human breast cancer, but the cause of tumour-associated MT expression is unknown. Studies are in progress to determine whether the MT state (apo [metal-free] or holo [metal-bound]) accounts for the paradoxical association of MT expression with individual types of tumours and the animal species in which they arise. Copyright Harcourt Publishers Ltd.

A Simple Metallothionein-Based Biosensor for Enhanced Detection of Arsenic and Mercury

PubMed Central

Irvine, Gordon W.; Tan, Swee Ngin; Stillman, Martin J.

2017-01-01

Metallothioneins (MTs) are a family of cysteine-rich proteins whose biological roles include the regulation of essential metal ions and protection against the harmful effects of toxic metals. Due to its high affinity for many toxic, soft metals, recombinant human MT isoform 1a was incorporated into an electrochemical-based biosensor for the detection of As3+ and Hg2+. A simple design was chosen to maximize its potential in environmental monitoring and MT was physically adsorbed onto paper discs placed on screen-printed carbon electrodes (SPCEs). This system was tested with concentrations of arsenic and mercury typical of contaminated water sources ranging from 5 to 1000 ppb. The analytical performance of the MT-adsorbed paper discs on SPCEs demonstrated a greater than three-fold signal enhancement and a lower detection limit compared to blank SPCEs, 13 ppb for As3+ and 45 ppb for Hg2+. While not being as low as some of the recommended drinking water limits, the sensitivity of the simple MT-biosensor would be potentially useful in monitoring of areas of concern with a known contamination problem. This paper describes the ability of the metal binding protein metallothionein to enhance the effectiveness of a simple, low-cost electrochemical sensor. PMID:28335390

GENETIC BACKGROUND BUT NOT METALLOTHIONEIN PHENOTYPE DICTATES SENSITIVITY TO CADMIUM-INDUCED TESTICULAR INJURY IN MICE

EPA Science Inventory

Genetic Background but not Metallothionein Phenotype Dictates Sensitivity to
Cadmium-Induced Testicular Injury in Mice

Jie Liu1,2, Chris Corton3, David J. Dix4, Yaping Liu1, Michael P. Waalkes2
and Curtis D. Klaassen1

ABSTRACT

Parenteral administrati...

Molecular control of copper homeostasis in filamentous fungi: increased expression of a metallothionein gene during aging of Podospora anserina.

PubMed

Averbeck, N B; Borghouts, C; Hamann, A; Specke, V; Osiewacz, H D

2001-01-01

The lifespan of the ascomycete Podospora anserina was previously demonstrated to be significantly increased in a copper-uptake mutant, suggesting that copper is a potential stressor involved in degenerative processes. In order to determine whether changes in copper stress occur in the cells during normal aging of cultures, we cloned and characterized a gene coding for a component of the molecular machinery involved in the control of copper homeostasis. This gene, PaMt1, is a single-copy gene that encodes a metallothionein of 26 amino acids. The coding sequence of PaMt1 is interrupted by a single intron. The deduced amino acid sequence shows a high degree of sequence identity to metallothioneins of the filamentous ascomycete Neurospora crassa and the basidiomycete Agaricus bisporus, and to the N-terminal portion of mammalian metallothioneins. Levels of PaMt1 transcript increase in response to elevated amounts of copper in the growth medium and during aging of wild-type cultures. In contrast, in the long-lived mutant grisea, transcript levels first increase but then decrease again. The ability of wild-type cultures to respond to exogenous copper stress via the induction of PaMt1 transcription is not affected as they grow older.

Isolation of metallothionein from cells derived from aggressive form of high-grade prostate carcinoma using paramagnetic antibody-modified microbeads off-line coupled with electrochemical and electrophoretic analysis.

PubMed

Masarik, Michal; Gumulec, Jaromir; Sztalmachova, Marketa; Hlavna, Marian; Babula, Petr; Krizkova, Sona; Ryvolova, Marketa; Jurajda, Michal; Sochor, Jiri; Adam, Vojtech; Kizek, Rene

2011-12-01

Prostate cancer with altered zinc(II) cell metabolism is the second most frequently diagnosed cancer in developed countries. The alterations of zinc(II) metabolism can influence metabolism of other metal ions and can also be associated with the expression and translation of metal-binding proteins including metallothioneins. The aim of this article was to optimize immunoseparation protocol based on paramagnetic beads conjugated with protein G for the isolation of metallothionein. Isolated metallothionein was determined by differential pulse voltammetry Brdicka reaction and SDS-PAGE. Optimal conditions: antigen-binding time - 60 min, temperature - 70°C, and buffer composition and pH - acetate buffer, pH 4.3, were determined. Under the optimized conditions, lysates from 22Rv1 prostate cancer cells treated with various concentrations of cadmium(II) and copper(II) ions were analyzed. We observed strong correlation in all experimental groups and all lysate types (r>0.83 at p<0.041) between metallothionein concentration related to viability and concentration of copper(II) ions and cadmium(II) ions in medium. Moreover, the results were compared with standard sample preparation as heat treatment and SDS-PAGE analysis. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A cadmium metallothionein gene of ridgetail white prawn Exopalaemon carinicauda (Holthuis, 1950) and its expression

NASA Astrophysics Data System (ADS)

Zhang, Jiquan; Wang, Jing; Xiang, Jianhai

2013-11-01

Metallothioneins (MTs) are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions. A cadmium metallothionein ( EcMT — Cd) cDNA with a 189 bp open reading frame (ORF) that encoded a 62 amino acid protein was obtained from Exopalaemon carinicauda. Seventeen cysteines were in the deduced amino acid sequence, and the cysteine (Cys)-rich characteristic was revealed in different metallothioneins in other species. In addition, the deduced amino acid sequence did not contain any aromatic amino acid residues, such as tyrosine (Tyr), tryptophan (Trp), and phenylalanine (Phe). EcMT—Cd mRNA was expressed in all tested tissues (the ovary, muscle, stomach, and hepatopancreas), and its expression profiles in the hepatopancreas were very different when shrimps were exposed to seawater containing either 50 μmol/L CuSO4 or 2.5 μmol/L CdCl 2. The expression of EcMT-Cd was significantly up-regulated in shrimp exposed to CuSO4 for 12 h and down-regulated in shrimps exposed to CdCl2 for 12 h. After 24 h exposure to both metals, its expression was down-regulated. By contrast, at 48 h the EcMT-Cd was up-regulated in test shrimps exposed to CdCl2. The transcript of EcMT-Cd was very low or even absent before the zoea stage, and the expression of EcMT-Cd was detected from mysis larvae-I, then its expression began to rise. In conclusion, a cadmium MT exists in E. carinicauda that is expressed in different tissues and during different developmental stages, and responds to the challenge with heavy metal ions, which provides a clue to understanding the function of cadmium MT.

Expression of metallothioneins I and II related to oxidative stress in the liver of aluminium-treated rats.

PubMed

Ghorbel, Imen; Chaabane, Mariem; Elwej, Awatef; Boudawara, Ons; Abdelhedi, Sameh; Jamoussi, Kamel; Boudawara, Tahya; Zeghal, Najiba

2016-10-01

Hepatotoxicity, induced by aluminium chloride (AlCl 3 ), has been well studied but there are no reports about liver metallothionein (MT) genes induction. Therefore, it is of interest to establish the mechanism involving the relation between MT gene expression levels and the oxidative stress status in hepatic cells of aluminium-treated rats. Aluminium (Al) was administered to rats in their drinking water at a dose of 50 mg/kg body weight for three weeks. AlCl 3 provoked hepatotoxicity objectified by an increase in malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), advanced oxidation protein products (AOPP), protein carbonyls (PCO) and a decrease in reduced glutathione (GSH), non-protein thiols (NPSH) and vitamin C. CAT and Glutathione peroxidase (GPx) activities were decreased while Mn-SOD gene expression, total Metallothionein content and MT I and MT II genes induction were increased. There are changes in plasma of some trace elements, albumin levels, transaminases, LDH and ALP activities. All these changes were supported by histopathological observations.

In vivo-folded metal-metallothionein 3 complexes reveal the Cu-thionein rather than Zn-thionein character of this brain-specific mammalian metallothionein.

PubMed

Artells, Ester; Palacios, Oscar; Capdevila, Mercè; Atrian, Sílvia

2014-03-01

Metallothionein-3 (MT3) is one of the four mammalian metallothioneins (MT), and is constitutively synthesized in the brain. MT3 acts both intracellularly and extracellularly in this organ, performing functions related to neuronal growth and physiological metal (Zn and Cu) handling. It appears to be involved in the prevention of neurodegenerative disorders caused by insoluble Cu-peptide aggregates, as it triggers a Zn-Cu swap that may counteract the deleterious presence of copper in neural tissues. The literature data on MT3 coordination come from studies either on apo-MT3 reconstitution or the reaction of Zn-MT3 with Cu(2+) , an ion that is hardly present inside cells. To ascertain the MT3 metal-binding features in a scenario closer to the reductive cell cytoplasm, a study of the recombinant Zn(2+) , Cd(2+) and Cu(+) complexes of MT3, βMT3, and αMT3, as well as the in vitro Zn(2+) -Cd(2+) and Zn(2+) -Cu(+) replacement processes, is presented here. We conclude that MT3 has a Cu-thionein character that is stronger than that of the MT1 and MT2 isoforms - also present in the mammalian brain - which is mainly contributed by its β domain. In contrast, the α domain retains a high capacity to bind Zn(2+) ions, and, consequently, the entire MT3 peptide shows a peculiar dual ability to handle both metal ions. The nature of the formed Cu(+) -MT3 complexes oscillates from heterometallic Cu6 Zn4 -MT3 to homometallic Cu10 -MT3 major species, in a narrow Cu concentration range. Therefore, the entire MT3 peptide shows a high capacity to bind Cu(+) , provided that this occurs in a nonoxidative milieux. This reflects a peculiar property of this MT isoform, which accurately senses different Cu contents in the environment in which it is synthesized. © 2014 FEBS.

A copper-induced metallothionein gene from Exopalaemon carinicauda and its response to heavy metal ions.

PubMed

Zhang, Jiquan; Wang, Jing; Gui, Tianshu; Sun, Zheng; Xiang, Jianhai

2014-09-01

A full-length copper-induced metallothionein (EcMT-Cu) cDNA was obtained from Exopalaemon carinicauda (Holthuis) and it contained a 198 bp open reading frame that encoded a peptide with 65 amino acid residues. Twenty-one cysteines were found in deduced amino acid sequence and the cysteine (Cys)-rich characteristic was also reported in different types of metallothioneins from other species. EcMT-Cu mRNA expression profile showed that it is the hepatopancreas specific gene. The expression of EcMT-Cu was extremely different when shrimp were exposed to seawater containing 50 μM CuSO4 or 2.5 μM CdCl2. The expression of EcMT-Cu in shrimp was significantly up-regulated at 12 and 24 h after exposure to CuSO4, however, its expression was not induced compared to that of pretreatment (p>0.05) when shrimp were exposed to CdCl2. The transcript of EcMT-Cu was found to be extremely low at gastrula and nauplius stage and expression of EcMT-Cu could be detected from egg protozoa stage. Copyright © 2014 Elsevier B.V. All rights reserved.

Metallothionein expression in chloroplasts enhances mercury accumulation and phytoremediation capability.

PubMed

Ruiz, Oscar N; Alvarez, Derry; Torres, Cesar; Roman, Laura; Daniell, Henry

2011-06-01

Genetic engineering to enhance mercury phytoremediation has been accomplished by expression of the merAB genes that protects the cell by converting Hg[II] into Hg[0] which volatilizes from the cell. A drawback of this approach is that toxic Hg is released back into the environment. A better phytoremediation strategy would be to accumulate mercury inside plants for subsequent retrieval. We report here the development of a transplastomic approach to express the mouse metallothionein gene (mt1) and accumulate mercury in high concentrations within plant cells. Real-time PCR analysis showed that up to 1284 copies of the mt1 gene were found per cell when compared with 1326 copies of the 16S rrn gene, thereby attaining homoplasmy. Past studies in chloroplast transformation used qualitative Southern blots to evaluate indirectly transgene copy number, whereas we used real-time PCR for the first time to establish homoplasmy and estimate transgene copy number and transcript levels. The mt1 transcript levels were very high with 183,000 copies per ng of RNA or 41% the abundance of the 16S rrn transcripts. The transplastomic lines were resistant up to 20 μm mercury and maintained high chlorophyll content and biomass. Although the transgenic plants accumulated high concentrations of mercury in all tissues, leaves accumulated up to 106 ng, indicating active phytoremediation and translocation of mercury. Such accumulation of mercury in plant tissues facilitates proper disposal or recycling. This study reports, for the first time, the use of metallothioneins in plants for mercury phytoremediation. Chloroplast genetic engineering approach is useful to express metal-scavenging proteins for phytoremediation. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

Bioimaging of metallothioneins in ocular tissue sections by laser ablation-ICP-MS using bioconjugated gold nanoclusters as specific tags.

PubMed

Cruz-Alonso, María; Fernandez, Beatriz; Álvarez, Lydia; González-Iglesias, Héctor; Traub, Heike; Jakubowski, Norbert; Pereiro, Rosario

2017-12-18

An immunohistochemical method is described to visualize the distribution of metallothioneins 1/2 (MT 1/2) and metallothionein 3 (MT 3) in human ocular tissue. It is making use of (a) antibodies conjugated to gold nanoclusters (AuNCs) acting as labels, and (b) laser ablation (LA) coupled to inductively coupled plasma - mass spectrometry (ICP-MS). Water-soluble fluorescent AuNCs (with an average size of 2.7 nm) were synthesized and then conjugated to antibody by carbodiimide coupling. The surface of the modified AuNCs was then blocked with hydroxylamine to avoid nonspecific interactions with biological tissue. Immunoassays for MT 1/2 and MT 3 in ocular tissue sections (5 μm thick) from two post mortem human donors were performed. Imaging studies were then performed by fluorescence using confocal microscopy, and LA-ICP-MS was performed in the retina to measure the signal for gold. Signal amplification by the >500 gold atoms in each nanocluster allowed the antigens (MT 1/2 and MT 3) to be imaged by LA-ICP-MS using a laser spot size as small as 4 μm. The image patterns found in retina are in good agreement with those obtained by conventional fluorescence immunohistochemistry which was used as an established reference method. Graphical abstract Gold nanoclusters (AuNCs) conjugated to a primary specific antibody serve as a label for amplified bioimaging of metallothioneins (MTs) by laser ablation coupled to inductively coupled plasma - mass spectrometry (ICP-MS) in human ocular tissue sections.

Improvement of n-butanol tolerance in Escherichia coli by membrane-targeted tilapia metallothionein

PubMed Central

2013-01-01

Background Though n-butanol has been proposed as a potential transportation biofuel, its toxicity often causes oxidative stress in the host microorganism and is considered one of the bottlenecks preventing its efficient mass production. Results To relieve the oxidative stress in the host cell, metallothioneins (MTs), which are known as scavengers for reactive oxygen species (ROS), were engineered in E. coli hosts for both cytosolic and outer-membrane-targeted (osmoregulatory membrane protein OmpC fused) expression. Metallothioneins from human (HMT), mouse (MMT), and tilapia fish (TMT) were tested. The host strain expressing membrane-targeted TMT showed the greatest ability to reduce oxidative stresses induced by n-butanol, ethanol, furfural, hydroxymethylfurfural, and nickel. The same strain also allowed for an increased growth rate of recombinant E. coli under n-butanol stress. Further experiments indicated that the TMT-fused OmpC protein could not only function in ROS scavenging but also regulate either glycine betaine (GB) or glucose uptake via osmosis, and the dual functional fusion protein could contribute in an enhancement of the host microorganism’s growth rate. Conclusions The abilities of scavenging intracellular or extracellular ROS by these engineering E. coli were examined, and TMT show the best ability among three MTs. Additionally, the membrane-targeted fusion protein, OmpC-TMT, improved host tolerance up to 1.5% n-butanol above that of TMT which is only 1%. These results presented indicate potential novel approaches for engineering stress tolerant microorganism strains. PMID:24020941

Improvement of n-butanol tolerance in Escherichia coli by membrane-targeted tilapia metallothionein.

PubMed

Chin, Wei-Chih; Lin, Kuo-Hsing; Chang, Jui-Jen; Huang, Chieh-Chen

2013-09-11

Though n-butanol has been proposed as a potential transportation biofuel, its toxicity often causes oxidative stress in the host microorganism and is considered one of the bottlenecks preventing its efficient mass production. To relieve the oxidative stress in the host cell, metallothioneins (MTs), which are known as scavengers for reactive oxygen species (ROS), were engineered in E. coli hosts for both cytosolic and outer-membrane-targeted (osmoregulatory membrane protein OmpC fused) expression. Metallothioneins from human (HMT), mouse (MMT), and tilapia fish (TMT) were tested. The host strain expressing membrane-targeted TMT showed the greatest ability to reduce oxidative stresses induced by n-butanol, ethanol, furfural, hydroxymethylfurfural, and nickel. The same strain also allowed for an increased growth rate of recombinant E. coli under n-butanol stress. Further experiments indicated that the TMT-fused OmpC protein could not only function in ROS scavenging but also regulate either glycine betaine (GB) or glucose uptake via osmosis, and the dual functional fusion protein could contribute in an enhancement of the host microorganism's growth rate. The abilities of scavenging intracellular or extracellular ROS by these engineering E. coli were examined, and TMT show the best ability among three MTs. Additionally, the membrane-targeted fusion protein, OmpC-TMT, improved host tolerance up to 1.5% n-butanol above that of TMT which is only 1%. These results presented indicate potential novel approaches for engineering stress tolerant microorganism strains.

Metallothionein - immunohistochemical cancer biomarker: a meta-analysis.

PubMed

Gumulec, Jaromir; Raudenska, Martina; Adam, Vojtech; Kizek, Rene; Masarik, Michal

2014-01-01

Metallothionein (MT) has been extensively investigated as a molecular marker of various types of cancer. In spite of the fact that numerous reviews have been published in this field, no meta-analytical approach has been performed. Therefore, results of to-date immunohistochemistry-based studies were summarized using meta-analysis in this review. Web of science, PubMed, Embase and CENTRAL databases were searched (up to April 30, 2013) and the eligibility of individual studies and heterogeneity among the studies was assessed. Random and fixed effects model meta-analysis was employed depending on the heterogeneity, and publication bias was evaluated using funnel plots and Egger's tests. A total of 77 studies were included with 8,015 tissue samples (4,631 cases and 3,384 controls). A significantly positive association between MT staining and tumors (vs. healthy tissues) was observed in head and neck (odds ratio, OR 9.95; 95% CI 5.82-17.03) and ovarian tumors (OR 7.83; 1.09-56.29), and a negative association was ascertained in liver tumors (OR 0.10; 0.03-0.30). No significant associations were identified in breast, colorectal, prostate, thyroid, stomach, bladder, kidney, gallbladder, and uterine cancers and in melanoma. While no associations were identified between MT and tumor staging, a positive association was identified with the tumor grade (OR 1.58; 1.08-2.30). In particular, strong associations were observed in breast, ovarian, uterine and prostate cancers. Borderline significant association of metastatic status and MT staining were determined (OR 1.59; 1.03-2.46), particularly in esophageal cancer. Additionally, a significant association between the patient prognosis and MT staining was also demonstrated (hazard ratio 2.04; 1.47-2.81). However, a high degree of inconsistence was observed in several tumor types, including colorectal, kidney and prostate cancer. Despite the ambiguity in some tumor types, conclusive results are provided in the tumors of head and

Efficient Plastid Transformation in Arabidopsis.

PubMed

Yu, Qiguo; Lutz, Kerry Ann; Maliga, Pal

2017-09-01

Plastid transformation is routine in tobacco ( Nicotiana tabacum ) but 100-fold less frequent in Arabidopsis ( Arabidopsis thaliana ), preventing its use in plastid biology. A recent study revealed that null mutations in ACC2 , encoding a plastid-targeted acetyl-coenzyme A carboxylase, cause hypersensitivity to spectinomycin. We hypothesized that plastid transformation efficiency should increase in the acc2 background, because when ACC2 is absent, fatty acid biosynthesis becomes dependent on translation of the plastid-encoded ACC β-carboxylase subunit. We bombarded ACC2 -defective Arabidopsis leaves with a vector carrying a selectable spectinomycin resistance ( aadA ) gene and gfp , encoding the green fluorescence protein GFP. Spectinomycin-resistant clones were identified as green cell clusters on a spectinomycin medium. Plastid transformation was confirmed by GFP accumulation from the second open reading frame of a polycistronic messenger RNA, which would not be translated in the cytoplasm. We obtained one to two plastid transformation events per bombarded sample in spectinomycin-hypersensitive Slavice and Columbia acc2 knockout backgrounds, an approximately 100-fold enhanced plastid transformation frequency. Slavice and Columbia are accessions in which plant regeneration is uncharacterized or difficult to obtain. A practical system for Arabidopsis plastid transformation will be obtained by creating an ACC2 null background in a regenerable Arabidopsis accession. The recognition that the duplicated ACCase in Arabidopsis is an impediment to plastid transformation provides a rational template to implement plastid transformation in related recalcitrant crops. © 2017 American Society of Plant Biologists. All Rights Reserved.

A rapid identification system for metallothionein proteins using expert system

PubMed Central

Praveen, Bhoopathi; Vincent, Savariar; Murty, Upadhyayula Suryanarayana; Krishna, Amirapu Radha; Jamil, Kaiser

2005-01-01

Metallothioneins (MT) are low molecular weight proteins mostly rich in cysteine residues with high metal content. Generally, MT proteins are responsible for regulating the intracellular supply of biologically essential metal ions and they protect cells from the deleterious effects of non-essential polarizable transition and post-transition metal ions. Due to their biological importance, proper characterization of MT is necessary. Here we describe a computer program (ID3 algorithm, a part of Artificial Intelligence) developed using available data for the rapid identification of MT. Tissue samples contains several low molecular weight proteins with different physical, chemical and biological characteristics. The described software solution proposes to categorize MT proteins without aromatic amino acids and high metal content. The proposed solution can be expanded to other types of proteins with specific known characteristics. PMID:17597844

The Stoichiometric Transition from Zn6Cu1-Metallothionein to Zn7-Metallothionein Underlies the Up-regulation of Metallothionein (MT) Expression

PubMed Central

Alvarez, Lydia; Gonzalez-Iglesias, Hector; Garcia, Montserrat; Ghosh, Sikha; Sanz-Medel, Alfredo; Coca-Prados, Miguel

2012-01-01

We examined the profiling of gene expression of metallothioneins (MTs) in human tissues from cadaver eyes with microarray-based analysis. All MT1 isoforms, with the exception of MT1B, were abundantly expressed in lens and corneal tissue. Along with MT1B, MT4 was not detected in any tissues. Antibodies to MT1/2 labeled the corneal epithelial and endothelial cells, whereas MT3 label the retinal ganglion cells. We studied the effects of zinc and cytokines on the gene expression of MT isoforms in a corneal epithelial cell line (HCEsv). Zinc exerted an up-regulation of the expression of MT isoforms, and this effect was further potentiated in the presence of IL1α or TNFα. Zinc also elicited a strong down-regulation of the expression of inflammatory cytokines, and this effect was blocked in the presence of TNFα or IL1α. The concentration of MTs, bound zinc, and the metal stoichiometry of MTs in cultured HCEsv were determined by mass spectrometry. The total concentration of MTs was 0.24 ± 0.03 μm and, after 24 h of zinc exposure, increased to 0.96 ± 0.01 μm. The combination of zinc and IL1α further enhanced the level of MTs to 1.13 ± 0.03 μm. The average metal stoichiometry of MTs was Zn6Cu1-MT, and after exposure to the different treatments, it changed to Zn7-MT. Actinomycin D blocked transcription, and cycloheximide attenuated synthesis of MTs in the presence or absence of zinc, suggesting transcriptional regulation. Overall the data provide molecular and analytical evidence on the interplay between zinc, MTs, and proinflammatory cytokines in HCEsv cells, with potential implications on cell-based inflammatory eye diseases. PMID:22722935

Cell Surface Display of Four Types of Solanum nigrum Metallothionein on Saccharomyces cerevisiae for Biosorption of Cadmium.

PubMed

Wei, Qinguo; Zhang, Honghai; Guo, Dongge; Ma, Shisheng

2016-05-28

We displayed four types of Solanum nigrum metallothionein (SMT) for the first time on the surface of Saccharomyces cerevisiae using an α-agglutinin-based display system. The SMT genes were amplified by RT-PCR. The plasmid pYES2 was used to construct the expression vector. Transformed yeast strains were confirmed by PCR amplification and custom sequencing. Surface-expressed metallothioneins were indirectly indicated by the enhanced cadmium sorption capacity. Flame atomic absorption spectrophotometry was used to examine the concentration of Cd(2+) in this study. The transformed yeast strains showed much higher resistance ability to Cd(2+) compared with the control. Strikingly, their Cd(2+) accumulation was almost twice as much as that of the wild-type yeast cells. Furthermore, surface-engineered yeast strains could effectively adsorb ultra-trace cadmium and accumulate Cd(2+) under a wide range of pH levels, from 3 to 7, without disturbing the Cu(2+) and Hg(2+). Four types of surfaceengineered Saccharomyces cerevisiae strains were constructed and they could be used to purify Cd(2+)-contaminated water and adsorb ultra-trace cadmium effectively. The surface-engineered Saccharomyces cerevisiae strains would be useful tools for the bioremediation and biosorption of environmental cadmium contaminants.

Expression pattern of a type-2 metallothionein gene in a wild population of the psammophyte Silene nicaeensis.

PubMed

Cozza, Radiana; Bruno, Leonardo; Bitonti, Maria Beatrice

2013-02-01

Silene nicaeensis is a wild Mediterranean grass often restricted to sandy sea shore and exhibiting an excellent tolerance to drought and salinity. Within Silene genus, several heavy metal-tolerant ecotypes have been identified, but information on molecular basis of such metal tolerance is still limited. Conceivably, salt-tolerant plants may represent a powerful tool for the remediation of heavy metal contaminated sites in saline environment. Here, a gene encoding a metallothionein protein was isolated from S. nicaeensis. Sequence analysis identified the motifs characteristic of type II metallothionein and designated as SnMT2. SnMT2 expression was investigated in plants collected from two sites differing in Metal Pollution Index (MPI). SnMT2 expression by polymerase chain reaction-based semi-quantitative transcript analysis showed a high accumulation in the leaves; in situ hybridization showed a steady localization of SnMT2 mRNA in the vascular bundle and in proliferating tissues. Moreover, an increase of SnMT2 was observed in the root of plants collected from area with higher MPI. The putative role of SnMT2 in metal tolerance is discussed.

Interaction of light and gravitropism with nutation of hypocotyls of Arabidopsis thaliana seedlings

NASA Technical Reports Server (NTRS)

Orbovic, V.; Poff, K. L.

1997-01-01

Etiolated seedlings of Arabidopsis thaliana nutated under conditions of physiological darkness while about ten percent of monitored individuals exhibited regular elliptical nutation, circumnutation. Pre-irradiation with red light prevented occurrence of circumnutation without having an effect on the average rate of the nutational movement. Phototropic response of seedlings to unilateral blue light appeared to be superimposed over nutation. Throughout gravitropism, some seedlings continued to exhibit nutation suggesting that these two processes are independently controlled. Based on these results, we suggest that nutation in Arabidopsis probably is not controlled by the mechanism predicted by the theory of gravitropic overshoots.

Metallothionein provides zinc-mediated protective effects against methamphetamine toxicity in SK-N-SH cells.

PubMed

Ajjimaporn, Amornpan; Swinscoe, John; Shavali, Shaik; Govitrapong, Piyarat; Ebadi, Manuchair

2005-11-30

Methamphetamine (METH) is a drug of abuse and neurotoxin that induces Parkinson's-like pathology after chronic usage by targeting dopaminergic neurons. Elucidation of the intracellular mechanisms that underlie METH-induced dopaminergic neuron toxicity may help in understanding the mechanism by which neurons die in Parkinson's disease. In the present study, we examined the role of reactive oxygen species (ROS) in the METH-induced death of human dopaminergic SK-N-SH cells and further assessed the neuroprotective effects of zinc and metallothionein (MT) against METH-induced toxicity in culture. METH significantly increased the production of reactive oxygen species, decreased intracellular ATP levels and reduced the cell viability. Pre-treatment with zinc markedly prevented the loss of cell viability caused by METH treatment. Zinc pre-treatment mainly increased the expression of metallothionein and prevented the generation of reactive oxygen species and ATP depletion caused by METH. Chelation of zinc by CaEDTA caused a significant decrease in MT expression and loss of protective effects of MT against METH toxicity. These results suggest that zinc-induced MT expression protects dopaminergic neurons via preventing the accumulation of toxic reactive oxygen species and halting the decrease in ATP levels. Furthermore, MT may prevent the loss of mitochondrial functions caused by neurotoxins. In conclusion, our study suggests that MT, a potent scavenger of free radicals is neuroprotective against dopaminergic toxicity in conditions such as drug of abuse and in Parkinson's disease.

An International Bioinformatics Infrastructure to Underpin the Arabidopsis Community

USDA-ARS?s Scientific Manuscript database

The future bioinformatics needs of the Arabidopsis community as well as those of other scientific communities that depend on Arabidopsis resources were discussed at a pair of recent meetings held by the Multinational Arabidopsis Steering Committee (MASC) and the North American Arabidopsis Steering C...

Zinc and Metallothionein in the Development and Progression of Dental Caries.

PubMed

Rahman, Mohammad Tariqur; Hossain, Ashfaque; Pin, Chew Hooi; Yahya, Noor Azlin

2018-05-09

Chronic oxidative stress and reactive oxygen species (ROS) in oral cavity as well as acidic pH on dental enamel surface due to the metabolic activities of bacterial plaque are the major contributors in the development and progression of dental caries. Along with other factors, deposition or dissolution Ca and Mg mostly determines the re- or demineralization of dental enamel. Zn plays an important role for both Ca and Mg bioavailability in oral cavity. Metallothionein (MT), a group of small molecular weight, cysteine-rich proteins (~ 7 kDa), is commonly induced by ROS, bacterial infection, and Zn. In the current review, we evaluated MT at the junction between the progression of dental caries and its etiologies that are common in MT biosynthesis.

A reference map of the Arabidopsis thaliana mature pollen proteome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noir, Sandra; Braeutigam, Anne; Colby, Thomas

The male gametophyte (or pollen) plays an obligatory role during sexual reproduction of higher plants. The extremely reduced complexity of this organ renders pollen a valuable experimental system for studying fundamental aspects of plant biology such as cell fate determination, cell-cell interactions, cell polarity, and tip-growth. Here, we present the first reference map of the mature pollen proteome of the dicotyledonous model plant species, Arabidopsis thaliana. Based on two-dimensional gel electrophoresis, matrix-assisted laser desorption/ionization time-of-flight, and electrospray quadrupole time-of-flight mass spectrometry, we reproducibly identified 121 different proteins in 145 individual spots. The presence, subcellular localization, and functional classification of themore » identified proteins are discussed in relation to the pollen transcriptome and the full protein complement encoded by the nuclear Arabidopsis genome.« less

Evaluation of metallothionein formation as a proxy for zinc absorption in an in vitro digestion/caco-2 cell culture model

USDA-ARS?s Scientific Manuscript database

Caco-2 cell metallothionein (MT) formation was studied to determine if MT could be used as a proxy for zinc (Zn) absorption in a cell culture model. MT intracellular concentration was determined by using a cadmium/hemoglobin affinity assay. Cellular Zn uptake was determined in acid digests (5% HNO3)...

Arabidopsis thaliana—Aphid Interaction

PubMed Central

Louis, Joe; Singh, Vijay; Shah, Jyoti

2012-01-01

Aphids are important pests of plants that use their stylets to tap into the sieve elements to consume phloem sap. Besides the removal of photosynthates, aphid infestation also alters source-sink patterns. Most aphids also vector viral diseases. In this chapter, we will summarize on recent significant findings in plant-aphid interaction, and how studies involving Arabidopsis thaliana and Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), are beginning to provide important insights into the molecular basis of plant defense and susceptibility to aphids. The recent demonstration that expression of dsRNA in Arabidopsis can be used to silence expression of genes in GPA has further expanded the utility of Arabidopsis for evaluating the contribution of the aphid genome-encoded proteins to this interaction. PMID:22666177

The early inflorescence of Arabidopsis thaliana demonstrates positional effects in floral organ growth and meristem patterning.

PubMed

Plackett, Andrew R G; Powers, Stephen J; Phillips, Andy L; Wilson, Zoe A; Hedden, Peter; Thomas, Stephen G

2018-06-01

Linear modelling approaches detected significant gradients in organ growth and patterning across early flowers of the Arabidopsis inflorescence and uncovered evidence of new roles for gibberellin in floral development. Most flowering plants, including the genetic model Arabidopsis thaliana, produce multiple flowers in sequence from a reproductive shoot apex to form a flower spike (inflorescence). The development of individual flowers on an Arabidopsis inflorescence has typically been considered as highly stereotypical and uniform, but this assumption is contradicted by the existence of mutants with phenotypes visible in early flowers only. This phenomenon is demonstrated by mutants partially impaired in the biosynthesis of the phytohormone gibberellin (GA), in which floral organ growth is retarded in the first flowers to be produced but has recovered spontaneously by the 10th flower. We presently lack systematic data from multiple flowers across the Arabidopsis inflorescence to explain such changes. Using mutants of the GA 20-OXIDASE (GA20ox) GA biosynthesis gene family to manipulate endogenous GA levels, we investigated the dynamics of changing floral organ growth across the early Arabidopsis inflorescence (flowers 1-10). Modelling of floral organ lengths identified a significant, GA-independent gradient of increasing stamen length relative to the pistil in the wild-type inflorescence that was separable from other, GA-dependent effects. It was also found that the first flowers exhibited unstable organ patterning in contrast to later flowers and that this instability was prolonged by exogenous GA treatment. These findings indicate that the development of individual flowers is influenced by hitherto unknown factors acting across the inflorescence and also suggest novel functions for GA in floral patterning.

Environmental History Modulates Arabidopsis Pattern-Triggered Immunity in a HISTONE ACETYLTRANSFERASE1-Dependent Manner.

PubMed

Singh, Prashant; Yekondi, Shweta; Chen, Po-Wen; Tsai, Chia-Hong; Yu, Chun-Wei; Wu, Keqiang; Zimmerli, Laurent

2014-06-01

In nature, plants are exposed to a fluctuating environment, and individuals exposed to contrasting environmental factors develop different environmental histories. Whether different environmental histories alter plant responses to a current stress remains elusive. Here, we show that environmental history modulates the plant response to microbial pathogens. Arabidopsis thaliana plants exposed to repetitive heat, cold, or salt stress were more resistant to virulent bacteria than Arabidopsis grown in a more stable environment. By contrast, long-term exposure to heat, cold, or exposure to high concentrations of NaCl did not provide enhanced protection against bacteria. Enhanced resistance occurred with priming of Arabidopsis pattern-triggered immunity (PTI)-responsive genes and the potentiation of PTI-mediated callose deposition. In repetitively stress-challenged Arabidopsis, PTI-responsive genes showed enrichment for epigenetic marks associated with transcriptional activation. Upon bacterial infection, enrichment of RNA polymerase II at primed PTI marker genes was observed in environmentally challenged Arabidopsis. Finally, repetitively stress-challenged histone acetyltransferase1-1 (hac1-1) mutants failed to demonstrate enhanced resistance to bacteria, priming of PTI, and increased open chromatin states. These findings reveal that environmental history shapes the plant response to bacteria through the development of a HAC1-dependent epigenetic mark characteristic of a primed PTI response, demonstrating a mechanistic link between the primed state in plants and epigenetics. © 2014 American Society of Plant Biologists. All rights reserved.

The unique C- and N-terminal sequences of Metallothionein isoform 3 mediate growth inhibition and Vectorial active transport in MCF-7 cells.

PubMed

Voels, Brent; Wang, Liping; Sens, Donald A; Garrett, Scott H; Zhang, Ke; Somji, Seema

2017-05-25

The 3rd isoform of the metallothionein (MT3) gene family has been shown to be overexpressed in most ductal breast cancers. A previous study has shown that the stable transfection of MCF-7 cells with the MT3 gene inhibits cell growth. The goal of the present study was to determine the role of the unique C-terminal and N-terminal sequences of MT3 on phenotypic properties and gene expression profiles of MCF-7 cells. MCF-7 cells were transfected with various metallothionein gene constructs which contain the insertion or the removal of the unique MT3 C- and N-terminal domains. Global gene expression analysis was performed on the MCF-7 cells containing the various constructs and the expression of the unique C- and N- terminal domains of MT3 was correlated to phenotypic properties of the cells. The results of the present study demonstrate that the C-terminal sequence of MT3, in the absence of the N-terminal sequence, induces dome formation in MCF-7 cells, which in cell cultures is the phenotypic manifestation of a cell's ability to perform vectorial active transport. Global gene expression analysis demonstrated that the increased expression of the GAGE gene family correlated with dome formation. Expression of the C-terminal domain induced GAGE gene expression, whereas the N-terminal domain inhibited GAGE gene expression and that the effect of the N-terminal domain inhibition was dominant over the C-terminal domain of MT3. Transfection with the metallothionein 1E gene increased the expression of GAGE genes. In addition, both the C- and the N-terminal sequences of the MT3 gene had growth inhibitory properties, which correlated to an increased expression of the interferon alpha-inducible protein 6. Our study shows that the C-terminal domain of MT3 confers dome formation in MCF-7 cells and the presence of this domain induces expression of the GAGE family of genes. The differential effects of MT3 and metallothionein 1E on the expression of GAGE genes suggests unique roles of

How to grow transgenic Arabidopsis in the field.

PubMed

Jänkänpää, Hanna Johansson; Jansson, Stefan

2012-01-01

Arabidopsis is naturally adapted to habitats in which both biotic variables (e.g., light, wind, and humidity) and abiotic variables (e.g., competition, herbivory, and pathogen densities) strongly fluctuate. Hence, conditions in controlled growth chambers (in which Arabidopsis is typically grown for scientific experiments) differ substantially from those in natural environments. In order to mimic more closely natural conditions, we grow Arabidopsis outdoors under "semi-natural" field conditions. Performing experiments on transgenic Arabidopsis grown in the field that are sufficiently reliable for publication is challenging. In this chapter, we present some of our experiences based on 10 years of field experimentation, which may be of use to researchers seeking to perform field experiments using transgenic Arabidopsis.

Arabidopsis Gene Family Profiler (aGFP)--user-oriented transcriptomic database with easy-to-use graphic interface.

PubMed

Dupl'áková, Nikoleta; Renák, David; Hovanec, Patrik; Honysová, Barbora; Twell, David; Honys, David

2007-07-23

Microarray technologies now belong to the standard functional genomics toolbox and have undergone massive development leading to increased genome coverage, accuracy and reliability. The number of experiments exploiting microarray technology has markedly increased in recent years. In parallel with the rapid accumulation of transcriptomic data, on-line analysis tools are being introduced to simplify their use. Global statistical data analysis methods contribute to the development of overall concepts about gene expression patterns and to query and compose working hypotheses. More recently, these applications are being supplemented with more specialized products offering visualization and specific data mining tools. We present a curated gene family-oriented gene expression database, Arabidopsis Gene Family Profiler (aGFP; http://agfp.ueb.cas.cz), which gives the user access to a large collection of normalised Affymetrix ATH1 microarray datasets. The database currently contains NASC Array and AtGenExpress transcriptomic datasets for various tissues at different developmental stages of wild type plants gathered from nearly 350 gene chips. The Arabidopsis GFP database has been designed as an easy-to-use tool for users needing an easily accessible resource for expression data of single genes, pre-defined gene families or custom gene sets, with the further possibility of keyword search. Arabidopsis Gene Family Profiler presents a user-friendly web interface using both graphic and text output. Data are stored at the MySQL server and individual queries are created in PHP script. The most distinguishable features of Arabidopsis Gene Family Profiler database are: 1) the presentation of normalized datasets (Affymetrix MAS algorithm and calculation of model-based gene-expression values based on the Perfect Match-only model); 2) the choice between two different normalization algorithms (Affymetrix MAS4 or MAS5 algorithms); 3) an intuitive interface; 4) an interactive "virtual

Phytoplasma effector SAP54 induces indeterminate leaf-like flower development in Arabidopsis plants.

PubMed

MacLean, Allyson M; Sugio, Akiko; Makarova, Olga V; Findlay, Kim C; Grieve, Victoria M; Tóth, Réka; Nicolaisen, Mogens; Hogenhout, Saskia A

2011-10-01

Phytoplasmas are insect-transmitted bacterial plant pathogens that cause considerable damage to a diverse range of agricultural crops globally. Symptoms induced in infected plants suggest that these phytopathogens may modulate developmental processes within the plant host. We report herein that Aster Yellows phytoplasma strain Witches' Broom (AY-WB) readily infects the model plant Arabidopsis (Arabidopsis thaliana) ecotype Columbia, inducing symptoms that are characteristic of phytoplasma infection, such as the production of green leaf-like flowers (virescence and phyllody) and increased formation of stems and branches (witches' broom). We found that the majority of genes encoding secreted AY-WB proteins (SAPs), which are candidate effector proteins, are expressed in Arabidopsis and the AY-WB insect vector Macrosteles quadrilineatus (Hemiptera; Cicadellidae). To identify which of these effector proteins induce symptoms of phyllody and virescence, we individually expressed the effector genes in Arabidopsis. From this screen, we have identified a novel AY-WB effector protein, SAP54, that alters floral development, resulting in the production of leaf-like flowers that are similar to those produced by plants infected with this phytoplasma. This study offers novel insight into the effector profile of an insect-transmitted plant pathogen and reports to our knowledge the first example of a microbial pathogen effector protein that targets flower development in a host.

Meiotic cytology and chromosome behaviour in wild-type Arabidopsis thaliana.

PubMed

Armstrong, Susan J; Jones, Gareth H

2003-01-01

This article reviews the historical development of cytology and cytogenetics in Arabidopsis, and summarizes recent developments in molecular cytogenetics, with special emphasis on meiotic studies. Despite the small genome and small chromosomes of Arabidopsis, considerable progress has been made in developing appropriate cytogenetical techniques for chromosome analysis. Fluorescence in situ hybridization (FISH) applied to extended meiotic pachytene chromosomes has resulted in a standardized karyotype (idiogram) for the species that has also been aligned with the genetical map. A better understanding of floral and meiotic development has been achieved by combining cytological studies, based on both sectioning and spreading techniques, with morphometric data and developmental landmarks. The meiotic interphase, preceding prophase I, has been investigated by marking the nuclei undergoing DNA replication with BrdU. This allowed the subclasses of meiotic interphase to be distinguished and also provided a means to time the duration of meiosis and its constituent phases. The FISH technique has been used to analyse in detail the meiotic organization of telomeres and centromeric regions. The results indicate that centromere regions do not play an active role in chromosome pairing and synapsis; however, telomeres pair homologously in advance of general chromosome synapsis. The FISH technique is currently being applied to analysing the pairing and synapsis of interstitial chromosome regions through interphase and prophase I. FISH probes also allow the five bivalents of Arabidopsis to be identified at metaphase I and this has permitted an analysis of chiasma frequencies in individual bivalents, both in wild-type Arabidopsis and in two meiotic mutants.

Dietary Supplementation of Blueberry Juice Enhances Hepatic Expression of Metallothionein and Attenuates Liver Fibrosis in Rats

PubMed Central

Wang, Yuping; Cheng, Mingliang; Zhang, Baofang; Nie, Fei; Jiang, Hongmei

2013-01-01

Aim To investigate the effect of blueberry juice intake on rat liver fibrosis and its influence on hepatic antioxidant defense. Methods Rabbiteye blueberry was used to prepare fresh juice to feed rats by daily gastric gavage. Dan-shao-hua-xian capsule (DSHX) was used as a positive control for liver fibrosis protection. Liver fibrosis was induced in male Sprague-Dawley rats by subcutaneous injection of CCl4 and feeding a high-lipid/low-protein diet for 8 weeks. Hepatic fibrosis was evaluated by Masson staining. The expression of α-smooth muscle actin (α-SMA) and collagen III (Col III) were determined by immunohistochemical techniques. The activities of superoxide dismutase (SOD) and malondialdehyde (MDA) in liver homogenates were determined. Metallothionein (MT) expression was detected by real-time RT-PCR and immunohistochemical techniques. Results Blueberry juice consumption significantly attenuates CCl4-induced rat hepatic fibrosis, which was associated with elevated expression of metallothionein (MT), increased SOD activity, reduced oxidative stress, and decreased levels of α-SMA and Col III in the liver. Conclusion Our study suggests that dietary supplementation of blueberry juice can augment antioxidative capability of the liver presumably via stimulating MT expression and SOD activity, which in turn promotes HSC inactivation and thus decreases extracellular matrix collagen accumulation in the liver, and thereby alleviating hepatic fibrosis. PMID:23554912

Structural consequences of metallothionein dimerization: solution structure of the isolated Cd4-alpha-domain and comparison with the holoprotein dimer.

PubMed

Ejnik, John W; Muñoz, Amalia; DeRose, Eugene; Shaw, C Frank; Petering, David H

2003-07-22

The NMR determination of the structure of Cd(7)-metallothionein was done previously using a relatively large protein concentration that favors dimer formation. The reactivity of the protein is also affected under this condition. To examine the influence of protein concentration on metallothionein conformation, the isolated Cd(4)-alpha-domain was prepared from rabbit metallothionein-2 (MT 2), and its three-dimensional structure was determined by heteronuclear, (1)H-(111)Cd, and homonuclear, (1)H-(1)H NMR, correlation experiments. The three-dimensional structure was refined using distance and angle constraints derived from these two-dimensional NMR data sets and a distance geometry/simulated annealing protocol. The backbone superposition of the alpha-domain from rabbit holoprotein Cd(7)-MT 2 and the isolated rabbit Cd(4)-alpha was measured at a RMSD of 2.0 A. Nevertheless, the conformations of the two Cd-thiolate clusters were distinctly different at two of the cadmium centers. In addition, solvent access to the sulfhydryl ligands of the isolated Cd(4)-alpha cluster was 130% larger due to this small change in cluster geometry. To probe whether these differences were an artifact of the structure calculation, the Cd(4)-alpha-domain structure in rabbit Cd(7)-MT 2 was redetermined, using the previously defined set of NOEs and the present calculation protocol. All calculations employed the same ionic radius for Cd(2+) and same cadmium-thiolate bond distance. The newly calculated structure matched the original with an RMSD of 1.24 A. It is hypothesized that differences in the two alpha-domain structures result from a perturbation of the holoprotein structure because of head-to-tail dimerization under the conditions of the NMR experiments.

Quantitative divergence of the bacterial root microbiota in Arabidopsis thaliana relatives

PubMed Central

Schlaeppi, Klaus; Dombrowski, Nina; Oter, Ruben Garrido; Ver Loren van Themaat, Emiel; Schulze-Lefert, Paul

2014-01-01

Plants host at the contact zone with soil a distinctive root-associated bacterial microbiota believed to function in plant nutrition and health. We investigated the diversity of the root microbiota within a phylogenetic framework of hosts: three Arabidopsis thaliana ecotypes along with its sister species Arabidopsis halleri and Arabidopsis lyrata, as well as Cardamine hirsuta, which diverged from the former ∼35 Mya. We surveyed their microbiota under controlled environmental conditions and of A. thaliana and C. hirsuta in two natural habitats. Deep 16S rRNA gene profiling of root and corresponding soil samples identified a total of 237 quantifiable bacterial ribotypes, of which an average of 73 community members were enriched in roots. The composition of this root microbiota depends more on interactions with the environment than with host species. Interhost species microbiota diversity is largely quantitative and is greater between the three Arabidopsis species than the three A. thaliana ecotypes. Host species-specific microbiota were identified at the levels of individual community members, taxonomic groups, and whole root communities. Most of these signatures were observed in the phylogenetically distant C. hirsuta. However, the branching order of host phylogeny is incongruent with interspecies root microbiota diversity, indicating that host phylogenetic distance alone cannot explain root microbiota diversification. Our work reveals within 35 My of host divergence a largely conserved and taxonomically narrow root microbiota, which comprises stable community members belonging to the Actinomycetales, Burkholderiales, and Flavobacteriales. PMID:24379374

Differential Effects of Carbohydrates on Arabidopsis Pollen Germination.

PubMed

Hirsche, Jörg; García Fernández, José M; Stabentheiner, Edith; Großkinsky, Dominik K; Roitsch, Thomas

2017-04-01

Pollen germination as a crucial process in plant development strongly depends on the accessibility of carbon as energy source. Carbohydrates, however, function not only as a primary energy source, but also as important signaling components. In a comprehensive study, we analyzed various aspects of the impact of 32 different sugars on in vitro germination of Arabidopsis pollen comprising about 150 variations of individual sugars and combinations. Twenty-six structurally different mono-, di- and oligosaccharides, and sugar analogs were initially tested for their ability to support pollen germination. Whereas several di- and oligosaccharides supported pollen germination, hexoses such as glucose, fructose and mannose did not support and even considerably inhibited pollen germination when added to germination-supporting medium. Complementary experiments using glucose analogs with varying functional features, the hexokinase inhibitor mannoheptulose and the glucose-insensitive hexokinase-deficient Arabidopsis mutant gin2-1 suggested that mannose- and glucose-mediated inhibition of sucrose-supported pollen germination depends partially on hexokinase signaling. The results suggest that, in addition to their role as energy source, sugars act as signaling molecules differentially regulating the complex process of pollen germination depending on their structural properties. Thus, a sugar-dependent multilayer regulation of Arabidopsis pollen germination is supported, which makes this approach a valuable experimental system for future studies addressing sugar sensing and signaling. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Acute and subacute pulmonary toxicity caused by a single intratracheal instillation of colloidal silver nanoparticles in mice: pathobiological changes and metallothionein responses.

PubMed

Kaewamatawong, Theerayuth; Banlunara, Wijit; Maneewattanapinyo, Pattwat; Thammachareon, Chuchaat; Ekgasit, Sanong

2014-01-01

To study the acute and subacute pulmonary toxicity of colloidal silver nanoparticles (Ag-NPs), 0 or 100 ppm of Ag-NPs were instilled intratracheally in mice. Cellular and biochemical parameters in bronchoalveolar lavage fluid (BALF) and histological alterations were determined 1, 3, 7, 15, and 30 days after instillation. Ag-NPs induced moderate pulmonary inflammation and injury on BALF indices during the acute period; however, these changes gradually regressed in a time-dependent manner. Concomitant histopathological and laminin immunohistochemical findings generally correlated to BALF data. Superoxide dismutase and metallothionein expression occurred in particle-laden macrophages and alveolar epithelial cells, which correlated to lung lesions in mice treated with Ag-NPs. These findings suggest that instillation of Ag-NPs causes transient moderate acute lung inflammation and tissue damage. Oxidative stress may underlie the induction of injury to lung tissue. Moreover, the expression of metallothionein in tissues indicated the protective response to exposure to Ag-NPs.

Age-related changes of metallothionein 1/2 and metallothionein 3 expression in rat brain.

PubMed

Scudiero, Rosaria; Cigliano, Luisa; Verderame, Mariailaria

2017-01-01

Neurodegeneration is one of the main physiological consequences of aging on brain. Metallothioneins (MTs), low molecular weight, cysteine-rich proteins that bind heavy-metal ions and oxygen-free radicals, are commonly expressed in various tissues of mammals. MTs are involved in the regulation of cell proliferation and protection, and may be engaged in aging. Expression of the ubiquitous MTs (1 and 2) and the brain specific MT3 have been studied in many neurodegenerative disorders. The research results indicate that MTs may play important, although not yet fully known, roles in brain diseases; in addition, data lack the ability to identify the MT isoforms functionally involved. The aim of this study was to analyse the level of gene expression of selected MT isoforms during brain aging. By using real-time PCR analysis, we determined the MT1/2 and MT3 expression profiles in cerebral cortex and hippocampus of adolescent (2months), adult (4 and 8months), and middle-aged (16months) rats. We show that the relative abundance of all types of MT transcripts changes during aging in both hippocampus and cortex; the first effect is a generalized decrease in the content of MTs transcripts from 2- to 8-months-old rats. After passing middle age, at 16months, we observe a huge increase in MT3 transcripts in both cortical and hippocampal areas, while the MT1/2 mRNA content increases slightly, returning to the levels measured in adolescent rats. These findings demonstrate an age-related expression of the MT3 gene. A possible link between the increasing amount of MT3 in brain aging and its different metal-binding behaviour is discussed. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Arabidopsis Leaf Trichomes as Acoustic Antennae.

PubMed

Liu, Shaobao; Jiao, Jiaojiao; Lu, Tian Jian; Xu, Feng; Pickard, Barbara G; Genin, Guy M

2017-11-07

The much studied plant Arabidopsis thaliana has been reported recently to react to the sounds of caterpillars of Pieris rapae chewing on its leaves by promoting synthesis of toxins that can deter herbivory. Identifying participating receptor cells-potential "ears"-of Arabidopsis is critical to understanding and harnessing this response. Motivated in part by other recent observations that Arabidopsis trichomes (hair cells) respond to mechanical stimuli such as pressing or brushing by initiating potential signaling factors in themselves and in the neighboring skirt of cells, we analyzed the vibrational responses of Arabidopsis trichomes to test the hypothesis that trichomes can respond acoustically to vibrations associated with feeding caterpillars. We found that these trichomes have vibrational modes in the frequency range of the sounds of feeding caterpillars, encouraging further experimentation to determine whether trichomes serve as mechanical antennae. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Starch Metabolism in Arabidopsis

PubMed Central

Streb, Sebastian; Zeeman, Samuel C.

2012-01-01

Starch is the major non-structural carbohydrate in plants. It serves as an important store of carbon that fuels plant metabolism and growth when they are unable to photosynthesise. This storage can be in leaves and other green tissues, where it is degraded during the night, or in heterotrophic tissues such as roots, seeds and tubers, where it is stored over longer time periods. Arabidopsis accumulates starch in many of its tissues, but mostly in its leaves during the day. It has proven to be a powerful genetic system for discovering how starch is synthesised and degraded, and new proteins and processes have been discovered. Such work has major significance for our starch crops, whose yield and quality could be improved by the application of this knowledge. Research into Arabidopsis starch metabolism has begun to reveal how its daily turnover is integrated into the rest of metabolism and adapted to the environmental conditions. Furthermore, Arabidopsis mutant lines deficient in starch metabolism have been employed as tools to study other biological processes ranging from sugar sensing to gravitropism and flowering time control. This review gives a detailed account of the use of Arabidopsis to study starch metabolism. It describes the major discoveries made and presents an overview of our understanding today, together with some as-yet unresolved questions. PMID:23393426

Large-scale atlas of microarray data reveals biological landscape of gene expression in Arabidopsis

USDA-ARS?s Scientific Manuscript database

Transcriptome datasets from thousands of samples of the model plant Arabidopsis thaliana have been collectively generated by multiple individual labs. Although integration and meta-analysis of these samples has become routine in the plant research community, it is often hampered by the lack of metad...

Characterization of calcineurin-dependent response element binding protein and its involvement in copper-metallothionein gene expression in Neurospora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Kalari Satish; Ravi Kumar, B.; Siddavattam, Dayananda

2006-07-07

In continuation of our recent observations indicating the presence of a lone calcineurin-dependent response element (CDRE) in the -3730 bp upstream region of copper-induced metallothionein (CuMT) gene of Neurospora [K.S. Kumar, S. Dayananda, C. Subramanyam, Copper alone, but not oxidative stress, induces copper-metallothionein gene in Neurospora crassa, FEMS Microbiol. Lett. 242 (2005) 45-50], we isolated and characterized the CDRE-binding protein. The cloned upstream region of CuMT gene was used as the template to specifically amplify CDRE element, which was immobilized on CNBr-activated Sepharose 4B for use as the affinity matrix to purify the CDRE binding protein from nuclear extracts obtainedmore » from Neurospora cultures grown in presence of copper. Two-dimensional gel electrophoresis of the affinity purified protein revealed the presence of a single 17 kDa protein, which was identified and characterized by MALDI-TOF. Peptide mass finger printing of tryptic digests and analysis of the 17 kDa protein matched with the regulatory {beta}-subunit of calcineurin (Ca{sup 2+}-calmodulin dependent protein phosphatase). Parallel identification of nuclear localization signals in this protein by in silico analysis suggests a putative role for calcineurin in the regulation of CuMT gene expression.« less

Metal ion release from metallothioneins: proteolysis as an alternative to oxidation.

PubMed

Peroza, Estevão A; dos Santos Cabral, Augusto; Wan, Xiaoqiong; Freisinger, Eva

2013-09-01

Metallothioneins (MTs) are among others involved in the cellular regulation of essential Zn(II) and Cu(I) ions. However, the high binding affinity of these proteins requires additional factors to promote metal ion release under physiological conditions. The mechanisms and efficiencies of these processes leave many open questions. We report here a comprehensive analysis of the Zn(II)-release properties of various MTs with special focus on members of the four main subfamilies of plant MTs. Zn(II) competition experiments with the metal ion chelator 4-(2-pyridylazo)resorcinol (PAR) in the presence of the cellular redox pair glutathione (GSH)/glutathione disulfide (GSSG) show that plant MTs from the subfamilies MT1, MT2, and MT3 are remarkably more affected by oxidative stress than those from the Ec subfamily and the well-characterized human MT2 form. In addition, we evaluated proteolytic digestion with trypsin and proteinase K as an alternative mechanism for selective promotion of metal ion release from MTs. Also here the observed percentage of liberated metal ions depends strongly on the MT form evaluated. Closer evaluation of the data additionally allowed deducing the thermodynamic and kinetic properties of the Zn(II) release processes. The Cu(I)-form of chickpea MT2 was used to exemplify that both oxidation and proteolysis are also effective ways to increase the transfer of copper ions to other molecules. Zn(II) release experiments with the individual metal-binding domains of Ec-1 from wheat grain reveal distinct differences from the full-length protein. This triggers the question about the roles of the long cysteine-free peptide stretches typical for plant MTs.

Arabidopsis thaliana as Bioindicator of Fungal VOCs in Indoor Air

PubMed Central

Hung, Richard; Yin, Guohua; Klich, Maren A.; Grimm, Casey; Bennett, Joan W.

2016-01-01

In this paper, we demonstrate the ability of Arabidopsis thaliana to detect different mixtures of volatile organic compounds (VOCs) emitted by the common indoor fungus, Aspergillus versicolor, and demonstrate the potential usage of the plant as a bioindicator to monitor fungal VOCs in indoor air. We evaluated the volatile production of Aspergillus versicolor strains SRRC 108 (NRRL 3449) and SRRC 2559 (ATCC 32662) grown on nutrient rich fungal medium, and grown under conditions to mimic the substrate encountered in the built environment where fungi would typically grow indoors (moist wallboard and ceiling tiles). Using headspace solid phase microextraction/gas chromatography-mass spectrometry, we analyzed VOC profiles of the two strains. The most abundant compound produced by both strains on all three media was 1-octen-3-ol. Strain SRRC 2559 made several terpenes not detected from strain SRRC 108. Using a split-plate bioassay, we grew Arabidopsis thaliana in a shared atmosphere with VOCs from the two strains of Aspergillus versicolor grown on yeast extract sucrose medium. The VOCs emitted by SRRC 2559 had an adverse impact on seed germination and plant growth. Chemical standards of individual VOCs from the Aspergillus versicolor mixture (2-methyl-1-butanol, 3-methyl-1-butanol, 1-octen-3-ol, limonene, and β-farnesene), and β-caryophyllene were tested one by one in seed germination and vegetative plant growth assays. The most inhibitory compound to both seed germination and plant growth was 1-octen-3-ol. Our data suggest that Arabidopsis is a useful model for monitoring indoor air quality as it is sensitive to naturally emitted fungal volatile mixtures as well as to chemical standards of individual compounds, and it exhibits relatively quick concentration- and duration-dependent responses. PMID:27790067

Arabidopsis thaliana as Bioindicator of Fungal VOCs in Indoor Air.

PubMed

Lee, Samantha; Hung, Richard; Yin, Guohua; Klich, Maren A; Grimm, Casey; Bennett, Joan W

2016-09-01

In this paper, we demonstrate the ability of Arabidopsis thaliana to detect different mixtures of volatile organic compounds (VOCs) emitted by the common indoor fungus, Aspergillus versicolor , and demonstrate the potential usage of the plant as a bioindicator to monitor fungal VOCs in indoor air. We evaluated the volatile production of Aspergillus versicolor strains SRRC 108 (NRRL 3449) and SRRC 2559 (ATCC 32662) grown on nutrient rich fungal medium, and grown under conditions to mimic the substrate encountered in the built environment where fungi would typically grow indoors (moist wallboard and ceiling tiles). Using headspace solid phase microextraction/gas chromatography-mass spectrometry, we analyzed VOC profiles of the two strains. The most abundant compound produced by both strains on all three media was 1-octen-3-ol. Strain SRRC 2559 made several terpenes not detected from strain SRRC 108. Using a split-plate bioassay, we grew Arabidopsis thaliana in a shared atmosphere with VOCs from the two strains of Aspergillus versicolor grown on yeast extract sucrose medium. The VOCs emitted by SRRC 2559 had an adverse impact on seed germination and plant growth. Chemical standards of individual VOCs from the Aspergillus versicolor mixture (2-methyl-1-butanol, 3-methyl-1-butanol, 1-octen-3-ol, limonene, and β-farnesene), and β-caryophyllene were tested one by one in seed germination and vegetative plant growth assays. The most inhibitory compound to both seed germination and plant growth was 1-octen-3-ol. Our data suggest that Arabidopsis is a useful model for monitoring indoor air quality as it is sensitive to naturally emitted fungal volatile mixtures as well as to chemical standards of individual compounds, and it exhibits relatively quick concentration- and duration-dependent responses.

Metallothionein as a compensatory component prevents intermittent hypoxia-induced cardiomyopathy in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Xia; Zhou, Shanshan; KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202

Obstructive sleep apnea (OSA) causes chronic intermittent hypoxia (IH) to induce cardiovascular disease, which may be related to oxidative damage. Metallothionein (MT) has been extensively proved to be an endogenous and highly inducible antioxidant protein expressed in the heart. Therefore, we tested the hypotheses that oxidative stress plays a critical role in OSA induced cardiac damage and MT protects the heart from OSA-induced cardiomyopathy. To mimic hypoxia/reoxygenation events that occur in adult OSA patients, mice were exposed to IH for 3 days to 8 weeks. The IH paradigm consisted of alternating cycles of 20.9% O{sub 2}/8% O{sub 2} F{sub I}O{submore » 2} (30 episodes per hour) with 20 s at the nadir F{sub I}O{sub 2} for 12 h a day during daylight. IH significantly increased the ratio of heart weight to tibia length at 4 weeks with a decrease in cardiac function from 4 to 8 weeks. Cardiac oxidative damage and fibrosis were observed after 4 and 8 weeks of IH exposures. Endogenous MT expression was up-regulated in response to 3-day IH, but significantly decreased at 4 and 8 weeks of IH. In support of MT as a major compensatory component, mice with cardiac overexpression of MT gene and mice with global MT gene deletion were completely resistant, and highly sensitive, respectively, to chronic IH induced cardiac effects. These findings suggest that chronic IH induces cardiomyopathy characterized by oxidative stress-mediated cardiac damage and the antioxidant MT protects the heart from such pathological and functional changes. - Highlights: • The effect of intermittent hypoxia (IH) on cardiac metallothionein (MT) • Cardiac MT expression was up-regulated in response to 3-day IH. • Exposure to 4- or 8-week IH downregulated cardiac MT expression. • Overexpression of cardiac MT protects from IH-induced cardiac damage. • Global deletion of MT gene made the heart more sensitive to IH damage.« less

Terpene Specialized Metabolism in Arabidopsis thaliana

PubMed Central

Tholl, Dorothea; Lee, Sungbeom

2011-01-01

Terpenes constitute the largest class of plant secondary (or specialized) metabolites, which are compounds of ecological function in plant defense or the attraction of beneficial organisms. Using biochemical and genetic approaches, nearly all Arabidopsis thaliana (Arabidopsis) enzymes of the core biosynthetic pathways producing the 5-carbon building blocks of terpenes have been characterized and closer insight has been gained into the transcriptional and posttranscriptional/translational mechanisms regulating these pathways. The biochemical function of most prenyltransferases, the downstream enzymes that condense the C5-precursors into central 10-, 15-, and 20-carbon prenyldiphosphate intermediates, has been described, although the function of several isoforms of C20-prenyltranferases is not well understood. Prenyl diphosphates are converted to a variety of C10-, C15-, and C20-terpene products by enzymes of the terpene synthase (TPS) family. Genomic organization of the 32 Arabidopsis TPS genes indicates a species-specific divergence of terpene synthases with tissue- and cell-type specific expression profiles that may have emerged under selection pressures by different organisms. Pseudogenization, differential expression, and subcellular segregation of TPS genes and enzymes contribute to the natural variation of terpene biosynthesis among Arabidopsis accessions (ecotypes) and species. Arabidopsis will remain an important model to investigate the metabolic organization and molecular regulatory networks of terpene specialized metabolism in relation to the biological activities of terpenes. PMID:22303268

Multigene Engineering of Triacylglycerol Metabolism Boosts Seed Oil Content in Arabidopsis1[W][OPEN

PubMed Central

van Erp, Harrie; Kelly, Amélie A.; Menard, Guillaume; Eastmond, Peter J.

2014-01-01

Increasing the yield of oilseed crops is an important objective for biotechnologists. A number of individual genes involved in triacylglycerol metabolism have previously been reported to enhance the oil content of seeds when their expression is altered. However, it has yet to be established whether specific combinations of these genes can be used to achieve an additive effect and whether this leads to enhanced yield. Using Arabidopsis (Arabidopsis thaliana) as an experimental system, we show that seed-specific overexpression of WRINKLED1 (a transcriptional regulator of glycolysis and fatty acid synthesis) and DIACYLGLYCEROL ACYLTRANSFERASE1 (a triacylglycerol biosynthetic enzyme) combined with suppression of the triacylglycerol lipase SUGAR-DEPENDENT1 results in a higher percentage seed oil content and greater seed mass than manipulation of each gene individually. Analysis of total seed yield per plant suggests that, despite a reduction in seed number, the total yield of oil is also increased. PMID:24696520

Transgenic Arabidopsis Gene Expression System

NASA Technical Reports Server (NTRS)

Ferl, Robert; Paul, Anna-Lisa

2009-01-01

The Transgenic Arabidopsis Gene Expression System (TAGES) investigation is one in a pair of investigations that use the Advanced Biological Research System (ABRS) facility. TAGES uses Arabidopsis thaliana, thale cress, with sensor promoter-reporter gene constructs that render the plants as biomonitors (an organism used to determine the quality of the surrounding environment) of their environment using real-time nondestructive Green Fluorescent Protein (GFP) imagery and traditional postflight analyses.

Phytotoxic effects of trichothecenes on the growth and morphology of Arabidopsis thaliana.

PubMed

Masuda, Daisuke; Ishida, Mamoru; Yamaguchi, Kazuo; Yamaguchi, Isamu; Kimura, Makoto; Nishiuchi, Takumi

2007-01-01

Non-volatile sesquiterpenoids, a trichothecene family of phytotoxins such as deoxynivalenol (DON) and T-2 toxin, contain numerous molecular species and are synthesized by phytopathogenic Fusarium species. Although trichothecene chemotypes might play a role in the virulence of individual Fusarium strains, the phytotoxic action of individual trichothecenes has not been systematically studied. To perform a comparative analysis of the phytotoxic action of representative trichothecenes, the growth and morphology of Arabidopsis thaliana growing on media containing these compounds was investigated. Both DON and diacetoxyscirpenol (DAS) preferentially inhibited root elongation. DON-treated roots were less organized compared with control roots. Moreover, preferential inhibition of root growth by DON was also observed in wheat plants. In addition, T-2 toxin-treated seedlings exhibited dwarfism with aberrant morphological changes (e.g. petiole shortening, curled dark-green leaves, and reduced cell size). These results imply that the phytotoxic action of trichothecenes differed among their molecular species. Cycloheximide (CHX)-treated seedlings displayed neither feature, although it is known that trichothecenes inhibit translation in eukaryotic ribosomes. Microarray analyses suggested that T-2 toxin caused a defence response, the inactivation of brassinosteroid (BR), and the generation of reactive oxygen species in Arabidopsis. This observation is in agreement with our previous reports in which trichothecenes such as T-2 toxin have an elicitor-like activity when infiltrated into the leaves of Arabidopsis. Since it has been reported that BR plays an important role in a broad range of disease resistance in tobacco and rice, inactivation of BR might affect pathogenicity during the infection of host plants by trichothecene-producing fungi.

Alternate approaches to repress endogenous microRNA activity in Arabidopsis thaliana

PubMed Central

Wang, Ming-Bo

2011-01-01

MicroRnAs (miRnAs) are an endogenous class of regulatory small RnA (sRnA). in plants, miRnAs are processed from short non-protein-coding messenger RnAs (mRnAs) transcribed from small miRnA genes (MIR genes). Traditionally in the model plant Arabidopsis thaliana (Arabidopsis), the functional analysis of a gene product has relied on the identification of a corresponding T-DnA insertion knockout mutant from a large, randomly-mutagenized population. However, because of the small size of MIR genes and presence of multiple, highly conserved members in most plant miRnA families, it has been extremely laborious and time consuming to obtain a corresponding single or multiple, null mutant plant line. Our recent study published in Molecular Plant1 outlines an alternate method for the functional characterization of miRnA action in Arabidopsis, termed anti-miRnA technology. Using this approach we demonstrated that the expression of individual miRnAs or entire miRnA families, can be readily and efficiently knocked-down. Our approach is in addition to two previously reported methodologies that also allow for the targeted suppression of either individual miRnAs, or all members of a MIR gene family; these include miRnA target mimicry2,3 and transcriptional gene silencing (TGS) of MIR gene promoters.4 All three methodologies rely on endogenous gene regulatory machinery and in this article we provide an overview of these technologies and discuss their strengths and weaknesses in inhibiting the activity of their targeted miRnA(s). PMID:21358288

Protein expression in Arabidopsis thaliana after chronic clinorotation

NASA Technical Reports Server (NTRS)

Piastuch, W. C.; Brown, C. S.

1995-01-01

Soluble protein expression in Arabidopsis thaliana L. (Heynh.) leaf and stem tissue was examined after chronic clinorotation. Seeds of Arabidopsis were germinated and plants grown to maturity on horizontal or vertical slow-rotating clinostats (1 rpm) or in stationary vertical control units. Total soluble proteins and in vivo-labeled soluble proteins isolated from these plants were analyzed by two-dimensional SDS PAGE and subsequent fluorography. Visual and computer analysis of the resulting protein patterns showed no significant differences in either total protein expression or in active protein synthesis between horizontal clinorotation and vertical controls in the Arabidopsis leaf and stem tissue. These results show chronic clinorotation does not cause gross changes in protein expression in Arabidopsis.

Metallothionein-1 and nitric oxide expression are inversely correlated in a murine model of Chagas disease

PubMed Central

Gonzalez-Mejia, Martha Elba; Torres-Rasgado, Enrique; Porchia, Leonardo M; Salgado, Hilda Rosas; Totolhua, José-Luis; Ortega, Arturo; Hernández-Kelly, Luisa Clara Regina; Ruiz-Vivanco, Guadalupe; Báez-Duarte, Blanca G; Pérez-Fuentes, Ricardo

2014-01-01

Chagas disease, caused by Trypanosoma cruzi, represents an endemic among Latin America countries. The participation of free radicals, especially nitric oxide (NO), has been demonstrated in the pathophysiology of seropositive individuals with T. cruzi. In Chagas disease, increased NO contributes to the development of cardiomyopathy and megacolon. Metallothioneins (MTs) are efficient free radicals scavengers of NO in vitro and in vivo. Here, we developed a murine model of the chronic phase of Chagas disease using endemic T. cruzi RyCH1 in BALB/c mice, which were divided into four groups: infected non-treated (Inf), infected N-monomethyl-L-arginine treated (Inf L-NAME), non-infected L-NAME treated and non-infected vehicle-treated. We determined blood parasitaemia and NO levels, the extent of parasite nests in tissues and liver MT-I expression levels. It was observed that NO levels were increasing in Inf mice in a time-dependent manner. Inf L-NAME mice had fewer T. cruzi nests in cardiac and skeletal muscle with decreased blood NO levels at day 135 post infection. This affect was negatively correlated with an increase of MT-I expression (r = -0.8462, p < 0.0001). In conclusion, we determined that in Chagas disease, an unknown inhibitory mechanism reduces MT-I expression, allowing augmented NO levels. PMID:24676665

A Molecular Portrait of Arabidopsis Meiosis

PubMed Central

Ma, Hong

2006-01-01

Meiosis is essential for eukaryotic sexual reproduction and important for genetic diversity among individuals. Efforts during the last decade in Arabidopsis have greatly expanded our understanding of the molecular basis of plant meiosis, which has traditionally provided much information about the cytological description of meiosis. Through both forward genetic analysis of mutants with reduced fertility and reverse genetic studies of homologs of known meiotic genes, we now have a basic knowledge about genes important for meiotic recombination and its relationship to pairing and synapsis, critical processes that ensure proper homolog segregation. In addition, several genes affecting meiotic progression, spindle assembly, chromosome separation, and meiotic cytokinesis have also been uncovered and characterized. It is worth noting that Arabidopsis molecular genetic studies are also revealing secrets of meiosis that have not yet been recognized elsewhere among eukaryotes, including gene functions that might be unique to plants and those that are potentially shared with animals and fungi. As we enter the post-genomics era of plant biology, there is no doubt that the next ten years will see an even greater number of discoveries in this important area of plant development and cell biology. Abbreviations: DAPI, 4′,6-diamidino-2-phenylindole; DSB, double strand break; DSBR, double strand break repair; SC, synaptonemal complex; TEM, transmission electron microscopy PMID:22303228

Protein expression in Arabidopsis thaliana after chronic clinorotation

NASA Technical Reports Server (NTRS)

Piastuch, William C.; Brown, Christopher S.

1994-01-01

Soluble protein expression in Arabidopsis thaliana L. (Heynh.) leaf and stem tissue was examined after chronic clinorotation. Seeds of Arabidopsis were germinated and plants grown to maturity on horizontal or vertical slow-rotating clinostats (1 rpm) or in stationary vertical control units. Total soluble proteins and in vivo-labeled soluble proteins isolated from these plants were analyzed by two-dimensional sodium doedocyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) and subsequent fluorography. Visual and computer analysis of the resulting protein patterns showed no significant differences in either total protein expression or in active protein synthesis between horizontal clinorotation and vertical controls in the Arabidopsis leaf and stem tissue. These results show chronic clinorotation does not cause gross changes in protein expression in Arabidopsis.

Using "Arabidopsis" Genetic Sequences to Teach Bioinformatics

ERIC Educational Resources Information Center

Zhang, Xiaorong

2009-01-01

This article describes a new approach to teaching bioinformatics using "Arabidopsis" genetic sequences. Several open-ended and inquiry-based laboratory exercises have been designed to help students grasp key concepts and gain practical skills in bioinformatics, using "Arabidopsis" leucine-rich repeat receptor-like kinase (LRR…

Gm1-MMP is involved in growth and development of leaf and seed, and enhances tolerance to high temperature and humidity stress in transgenic Arabidopsis.

PubMed

Liu, Sushuang; Liu, Yanmin; Jia, Yanhong; Wei, Jiaping; Wang, Shuang; Liu, Xiaolin; Zhou, Yali; Zhu, Yajing; Gu, Weihong; Ma, Hao

2017-06-01

Matrix metalloproteinases (MMPs) are a family of zinc- and calcium-dependent endopeptidases. Gm1-MMP was found to play an important role in soybean tissue remodeling during leaf expansion. In this study, Gm1-MMP was isolated and characterized. Its encoding protein had a relatively low phylogenetic relationship with the MMPs in other plant species. Subcellular localization indicated that Gm1-MMP was a plasma membrane protein. Gm1-MMP showed higher expression levels in mature leaves, old leaves, pods, and mature seeds, as well as was involved in the development of soybean seed. Additionally, it was involved in response to high temperature and humidity (HTH) stress in R7 leaves and seeds in soybean. The analysis of promoter of Gm1-MMP suggested that the fragment from -399 to -299 was essential for its promoter activity in response to HTH stress. The overexpression of Gm1-MMP in Arabidopsis affected the growth and development of leaves, enhanced leaf and developing seed tolerance to HTH stress and improved seed vitality. The levels of hydrogen peroxide (H 2 O 2 ) and ROS in transgenic Arabidopsis seeds were lower than those in wild type seeds under HTH stress. Gm1-MMP could interact with soybean metallothionein-II (GmMT-II), which was confirmed by analysis of yeast two-hybrid assay and BiFC assays. All the results indicated that Gm1-MMP plays an important role in the growth and development of leaves and seeds as well as in tolerance to HTH stress. It will be helpful for us understanding the functions of Gm1-MMP in plant growth and development, and in response to abiotic stresses. Copyright © 2017 Elsevier B.V. All rights reserved.

RARGE II: an integrated phenotype database of Arabidopsis mutant traits using a controlled vocabulary.

PubMed

Akiyama, Kenji; Kurotani, Atsushi; Iida, Kei; Kuromori, Takashi; Shinozaki, Kazuo; Sakurai, Tetsuya

2014-01-01

Arabidopsis thaliana is one of the most popular experimental plants. However, only 40% of its genes have at least one experimental Gene Ontology (GO) annotation assigned. Systematic observation of mutant phenotypes is an important technique for elucidating gene functions. Indeed, several large-scale phenotypic analyses have been performed and have generated phenotypic data sets from many Arabidopsis mutant lines and overexpressing lines, which are freely available online. Since each Arabidopsis mutant line database uses individual phenotype expression, the differences in the structured term sets used by each database make it difficult to compare data sets and make it impossible to search across databases. Therefore, we obtained publicly available information for a total of 66,209 Arabidopsis mutant lines, including loss-of-function (RATM and TARAPPER) and gain-of-function (AtFOX and OsFOX) lines, and integrated the phenotype data by mapping the descriptions onto Plant Ontology (PO) and Phenotypic Quality Ontology (PATO) terms. This approach made it possible to manage the four different phenotype databases as one large data set. Here, we report a publicly accessible web-based database, the RIKEN Arabidopsis Genome Encyclopedia II (RARGE II; http://rarge-v2.psc.riken.jp/), in which all of the data described in this study are included. Using the database, we demonstrated consistency (in terms of protein function) with a previous study and identified the presumed function of an unknown gene. We provide examples of AT1G21600, which is a subunit in the plastid-encoded RNA polymerase complex, and AT5G56980, which is related to the jasmonic acid signaling pathway.

Serum Metallothioneins in Childhood Tumours—A Potential Prognostic Marker

PubMed Central

Kruseova, Jarmila; Hynek, David; Adam, Vojtech; Kizek, Rene; Prusa, Richard; Hrabeta, Jan; Eckschlager, Tomas

2013-01-01

Metallothioneins (MT) are low molecular weight, cysteine-rich proteins maintaining metal ions homeostasis. They play a role in carcinogenesis and may also cause chemoresistance. The aim of the study was to explore the importance of MT serum levels in children suffering from malignant tumours. This prospective study involves examination of 865 samples from 172 patients with malignant tumours treated from 2008 to 2011 at University Hospital Motol. MT serum levels were determined using differential pulse voltammetry–Brdicka reaction. Mean MT level was 2.7 ± 0.5 μM. There was no statistically significant difference between MT levels in different tumours. We also did not find any correlation between MT levels and response to therapy or clinical stages. However, we found a positive correlation between MT levels and age (p = 0.009) and a negative correlation with absolute lymphocyte number (p = 0.001). The fact that patients who had early disease recurrence had lower MT levels during the treatment (complete remission 2.67 vs. recurring 2.34, p = 0.001) seems to be important for clinical practice. Accordingly we believe that there is benefit in further studies of serum MT levels in tumours. PMID:23743828

Overexpression of Arabidopsis AnnAt8 Alleviates Abiotic Stress in Transgenic Arabidopsis and Tobacco

PubMed Central

Yadav, Deepanker; Ahmed, Israr; Shukla, Pawan; Boyidi, Prasanna; Kirti, Pulugurtha Bharadwaja

2016-01-01

Abiotic stress results in massive loss of crop productivity throughout the world. Because of our limited knowledge of the plant defense mechanisms, it is very difficult to exploit the plant genetic resources for manipulation of traits that could benefit multiple stress tolerance in plants. To achieve this, we need a deeper understanding of the plant gene regulatory mechanisms involved in stress responses. Understanding the roles of different members of plant gene families involved in different stress responses, would be a step in this direction. Arabidopsis, which served as a model system for the plant research, is also the most suitable system for the functional characterization of plant gene families. Annexin family in Arabidopsis also is one gene family which has not been fully explored. Eight annexin genes have been reported in the genome of Arabidopsis thaliana. Expression studies of different Arabidopsis annexins revealed their differential regulation under various abiotic stress conditions. AnnAt8 (At5g12380), a member of this family has been shown to exhibit ~433 and ~175 fold increase in transcript levels under NaCl and dehydration stress respectively. To characterize Annexin8 (AnnAt8) further, we have generated transgenic Arabidopsis and tobacco plants constitutively expressing AnnAt8, which were evaluated under different abiotic stress conditions. AnnAt8 overexpressing transgenic plants exhibited higher seed germination rates, better plant growth, and higher chlorophyll retention when compared to wild type plants under abiotic stress treatments. Under stress conditions transgenic plants showed comparatively higher levels of proline and lower levels of malondialdehyde compared to the wild-type plants. Real-Time PCR analyses revealed that the expression of several stress-regulated genes was altered in AnnAt8 over-expressing transgenic tobacco plants, and the enhanced tolerance exhibited by the transgenic plants can be correlated with altered expressions of

Induction of metallothionein synthesis in transplanted murine tumors by X irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiyoshi, Shibuya; Masahiko Satoh; Yuzo, Watanabe

1995-07-01

Although recent studies have shown that radiation can induce metallothionein (MT) synthesis in normal tissues, the induction of tumor MT synthesis by irradiation has not been reported. We examined the accumulation of MT in the Meth-A tumor (mouse fibrosarcoma cells) transplanted into mice exposed to whole-body X irradiation. In the present study, the MT content in the tumor cells was increased by X irradiation in a dose-dependent manner. The MT level induced in the tumor cells by X irradiation was elevated not only after a single exposure but also after repeated exposures. Several studies have shown that MT is onemore » of the important cellular factors in resistance to various anti-cancer drugs and ionizing radiation. Thus our results suggest that the radiation-induced MT in the tumor cells may have to be taken into consideration when designing protocols for radio-and chemotherapy. 29 refs., 3 figs.« less

Expression of Metallothionein and Vascular Endothelial Growth Factor Isoforms in Breast Cancer Cells.

PubMed

Wierzowiecka, Barbara; Gomulkiewicz, Agnieszka; Cwynar-Zajac, Lucja; Olbromski, Mateusz; Grzegrzolka, Jedrzej; Kobierzycki, Christopher; Podhorska-Okolow, Marzenna; Dziegiel, Piotr

2016-01-01

Metallothioneins (MTs) are low-molecular-weight and cysteine-rich proteins that bind heavy metal ions and oxygen-free radicals. MTs are commonly expressed in various tissues of mammals and are involved in regulation of cell proliferation and differentiation, and may be engaged in angiogenesis. Expression of MTs has been studied in many cancer types, especially breast cancer. The research results indicate that MTs may play important, although not yet fully known, roles in cancer angiogenesis. The aim of this study was to analyze the level of gene expression of selected MT isoforms induced with zinc ions in correlation with vascular endothelial growth factor (VEGF) isoforms in in vitro models of breast cancer. The studies were carried out in three breast cancer cell lines (MCF-7, SK-BR-3, MDA-MB-231). An epithelial cell line derived from normal breast tissue (Me16c) was used as a control. The levels of expression of selected MT isoforms and selected genes involved in angiogenesis were studied with real-time PCR. Expression of different MT isoforms was induced by zinc ions to differing degrees in individual breast cancer cell lines. An increase in the expression of some MT isoforms was associated with a slight increase in the level of expression of VEGFA. The research results may indicate certain correlation between an increased expression of selected MT isoforms and a pro-angiogenic factor VEGF in specific types of breast cancer cells. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Expression, purification of metallothionein genes from freshwater crab (Sinopotamon yangtsekiense) and development of an anti-metallothionein ELISA

PubMed Central

Zhang, Hao; Zhou, Hui

2017-01-01

Using the phoA-fusion technology, the recombinant metallothionein (MT) from freshwater crab (Sinopotamon yangtsekiense) has been successfully produced in Escherichia coli. MT purified from the bacterial suspension showed one polypeptide with a molecular weight of 7 kDa by tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Tricine-SDS-PAGE). Western-blotting confirmed the polypeptides had a specific reactivity with mouse polyclonal MT anti-serum. Based on the purified MT and MT anti-serum, the reaction parameters for an enzyme-linked immunosorbent assay (ELISA) were developed. The direct coating ELISA showed a higher linear relationship compared to antibody sandwich coating ELISA. The optimal dilution rates of purified MT anti-serum and coating period were shown to be 1:160,000 and 12 hours at 4°C. At 37°C, the appropriate reaction duration of the first antibody and the second antibody were 2 hours and 1 hour, respectively. According to these optimal parameters, the standard linear equation, y = 0.0032x + 0.1769 (R2 = 0.9779, x, y representing MT concentration and OD450 value), was established for the determination of MT concentration with a valid range of 3.9–500 ng/ml. In verification experiments, the mean coefficients of variation of the intra-assay and inter-assay were 3.260% and 3.736%, respectively. According to the result of MT recovery, ELISA with an approaching 100% MT recovery was more reliable and sensitive than the Cd saturation assay. In conclusion, the newly developed ELISA of this study was precise, stable and repeatable, and could be used as a biomarker tool to monitor pollution by heavy metals. PMID:28350826

A synthetic cadmium metallothionein gene (PMCd1syn) of Paramecium species: expression, purification and characteristics of metallothionein protein.

PubMed

Dar, Saira; Shuja, Rukhsana N; Shakoori, Abdul Rauf

2013-02-01

Metallothioneins (MTs) are metal binding proteins that are rich in cysteine residues constituting 10-30 % of the total protein, and in which the thiol groups bind to the metal ions. The increasing amount of metal ions in the medium have shown increased production of MTs by different organisms such as bacteria, protozoa and mammals like humans. PMCd1 is the first gene ever discovered in Paramecium, a ciliated protozoan, that could produce this MT in response to cadmium. In this study the PMCd1syn gene has been cloned in pET41a expression vector and expressed in an Escherichia coli BL21-codonplus strain for the first time. Since the gene PMCd1 amplified from Paramecium contained 10 codons, which could act as stop codons during expression in E. coli, this gene of 612 bps was synthesized to substitute these (stop) codons for the Paramecium sp. specific amino acids. For stability of the expressed protein, glutathione-S-transferase gene was fused with PMCd1syn gene and coexpressed. The cells expressing PMCd1syn demonstrated increased accumulation of cadmium. This is the first report of cadmium MT protein expressed from Paramecium species, particularly from synthetic MT gene (PMCd1syn). This fusion protein, the molecular weight of which has been confirmed to be 53.03 kDa with MALDI analysis, is rich in cysteine residues, and has been shown for the first time in this ciliate to bind to and sequester Cd(2+)-ions.

Identification of Pseudomonas syringae pathogens of Arabidopsis and a bacterial locus determining avirulence on both Arabidopsis and soybean.

PubMed

Whalen, M C; Innes, R W; Bent, A F; Staskawicz, B J

1991-01-01

To develop a model system for molecular genetic analysis of plant-pathogen interactions, we studied the interaction between Arabidopsis thaliana and the bacterial pathogen Pseudomonas syringae pv tomato (Pst). Pst strains were found to be virulent or avirulent on specific Arabidopsis ecotypes, and single ecotypes were resistant to some Pst strains and susceptible to others. In many plant-pathogen interactions, disease resistance is controlled by the simultaneous presence of single plant resistance genes and single pathogen avirulence genes. Therefore, we tested whether avirulence genes in Pst controlled induction of resistance in Arabidopsis. Cosmids that determine avirulence were isolated from Pst genomic libraries, and the Pst avirulence locus avrRpt2 was defined. This allowed us to construct pathogens that differed only by the presence or absence of a single putative avirulence gene. We found that Arabidopsis ecotype Col-0 was susceptible to Pst strain DC3000 but resistant to the same strain carrying avrRpt2, suggesting that a single locus in Col-0 determines resistance. As a first step toward genetically mapping the postulated resistance locus, an ecotype susceptible to infection by DC3000 carrying avrRpt2 was identified. The avrRpt2 locus from Pst was also moved into virulent strains of the soybean pathogen P. syringae pv glycinea to test whether this locus could determine avirulence on soybean. The resulting strains induced a resistant response in a cultivar-specific manner, suggesting that similar resistance mechanisms may function in Arabidopsis and soybean.

VIZARD: analysis of Affymetrix Arabidopsis GeneChip data

NASA Technical Reports Server (NTRS)

Moseyko, Nick; Feldman, Lewis J.

2002-01-01

SUMMARY: The Affymetrix GeneChip Arabidopsis genome array has proved to be a very powerful tool for the analysis of gene expression in Arabidopsis thaliana, the most commonly studied plant model organism. VIZARD is a Java program created at the University of California, Berkeley, to facilitate analysis of Arabidopsis GeneChip data. It includes several integrated tools for filtering, sorting, clustering and visualization of gene expression data as well as tools for the discovery of regulatory motifs in upstream sequences. VIZARD also includes annotation and upstream sequence databases for the majority of genes represented on the Affymetrix Arabidopsis GeneChip array. AVAILABILITY: VIZARD is available free of charge for educational, research, and not-for-profit purposes, and can be downloaded at http://www.anm.f2s.com/research/vizard/ CONTACT: moseyko@uclink4.berkeley.edu.

Arabidopsis intragenomic conserved noncoding sequence

PubMed Central

Thomas, Brian C.; Rapaka, Lakshmi; Lyons, Eric; Pedersen, Brent; Freeling, Michael

2007-01-01

After the most recent tetraploidy in the Arabidopsis lineage, most gene pairs lost one, but not both, of their duplicates. We manually inspected the 3,179 retained gene pairs and their surrounding gene space still present in the genome using a custom-made viewer application. The display of these pairs allowed us to define intragenic conserved noncoding sequences (CNSs), identify exon annotation errors, and discover potentially new genes. Using a strict algorithm to sort high-scoring pair sequences from the bl2seq data, we created a database of 14,944 intragenomic Arabidopsis CNSs. The mean CNS length is 31 bp, ranging from 15 to 285 bp. There are ≈1.7 CNSs associated with a typical gene, and Arabidopsis CNSs are found in all areas around exons, most frequently in the 5′ upstream region. Gene ontology classifications related to transcription, regulation, or “response to …” external or endogenous stimuli, especially hormones, tend to be significantly overrepresented among genes containing a large number of CNSs, whereas protein localization, transport, and metabolism are common among genes with no CNSs. There is a 1.5% overlap between these CNSs and the 218,982 putative RNAs in the Arabidopsis Small RNA Project database, allowing for two mismatches. These CNSs provide a unique set of noncoding sequences enriched for function. CNS function is implied by evolutionary conservation and independently supported because CNS-richness predicts regulatory gene ontology categories. PMID:17301222

Functional Annotation of the Arabidopsis Genome Using Controlled Vocabularies1

PubMed Central

Berardini, Tanya Z.; Mundodi, Suparna; Reiser, Leonore; Huala, Eva; Garcia-Hernandez, Margarita; Zhang, Peifen; Mueller, Lukas A.; Yoon, Jungwoon; Doyle, Aisling; Lander, Gabriel; Moseyko, Nick; Yoo, Danny; Xu, Iris; Zoeckler, Brandon; Montoya, Mary; Miller, Neil; Weems, Dan; Rhee, Seung Y.

2004-01-01

Controlled vocabularies are increasingly used by databases to describe genes and gene products because they facilitate identification of similar genes within an organism or among different organisms. One of The Arabidopsis Information Resource's goals is to associate all Arabidopsis genes with terms developed by the Gene Ontology Consortium that describe the molecular function, biological process, and subcellular location of a gene product. We have also developed terms describing Arabidopsis anatomy and developmental stages and use these to annotate published gene expression data. As of March 2004, we used computational and manual annotation methods to make 85,666 annotations representing 26,624 unique loci. We focus on associating genes to controlled vocabulary terms based on experimental data from the literature and use The Arabidopsis Information Resource-developed PubSearch software to facilitate this process. Each annotation is tagged with a combination of evidence codes, evidence descriptions, and references that provide a robust means to assess data quality. Annotation of all Arabidopsis genes will allow quantitative comparisons between sets of genes derived from sources such as microarray experiments. The Arabidopsis annotation data will also facilitate annotation of newly sequenced plant genomes by using sequence similarity to transfer annotations to homologous genes. In addition, complete and up-to-date annotations will make unknown genes easy to identify and target for experimentation. Here, we describe the process of Arabidopsis functional annotation using a variety of data sources and illustrate several ways in which this information can be accessed and used to infer knowledge about Arabidopsis and other plant species. PMID:15173566

Metallothionein-3 modulates the amyloid β endocytosis of astrocytes through its effects on actin polymerization.

PubMed

Lee, Sook-Jeong; Seo, Bo-Ra; Koh, Jae-Young

2015-12-04

Astrocytes may play important roles in the pathogenesis of Alzheimer's disease (AD) by clearing extracellular amyloid beta (Aβ) through endocytosis and degradation. We recently showed that metallothionein 3 (Mt3), a zinc-binding metallothionein that is enriched in the central nervous system, contributes to actin polymerization in astrocytes. Because actin is likely involved in the endocytosis of Aβ, we investigated the possible role of Mt3 in Aβ endocytosis by cortical astrocytes in this study. To assess the route of Aβ uptake, we exposed cultured astrocytes to fluorescently labeled Aβ1-40 or Aβ1-42 together with chloropromazine (CP) or methyl-beta-cyclodextrin (MβCD), inhibitors of clathrin- and caveolin-dependent endocytosis, respectively. CP treatment almost completely blocked Aβ1-40 and Aβ1-42 endocytosis, whereas exposure to MβCD had no significant effect. Actin disruption with cytochalasin D (CytD) or latrunculin B also completely blocked Aβ1-40 and Aβ1-42 endocytosis. Because the absence of Mt3 also results in actin disruption, we examined Aβ1-40 and Aβ1-42 uptake and expression in Mt3 (-/-) astrocytes. Compared with wild-type (WT) cells, Mt3 (-/-) cells exhibited markedly reduced Aβ1-40 and Aβ1-42 endocytosis and expression of Aβ1-42 monomers and oligomers. A similar reduction was observed in CytD-treated WT cells. Finally, actin disruption and Mt3 knockout each increased the overall levels of clathrin and the associated protein phosphatidylinositol-binding clathrin assembly protein (PICALM) in astrocytes. Our results suggest that the absence of Mt3 reduces Aβ uptake in astrocytes through an abnormality in actin polymerization. In light of evidence that Mt3 is downregulated in AD, our findings indicate that this mechanism may contribute to the extracellular accumulation of Aβ in this disease.

Induction of Metallothionein Expression After Exposure to Conventional Cigarette Smoke but Not Electronic Cigarette (ECIG)-Generated Aerosol in Caenorhabditis elegans

PubMed Central

Cobb, Eric; Hall, Julie; Palazzolo, Dominic L.

2018-01-01

Aim: With the invention of electronic cigarettes (ECIG), many questions have been raised regarding their safety as an alternative to smoking conventional cigarettes. Conventional cigarette smoke contains a variety of toxicants including heavy metals. However, ECIG-generated aerosol contains only trace amounts of metals, adding to the argument for it being a safer alternative. In response to heavy metal exposure, metallothioneins are induced in cells to help store the metal, detoxify the body, and are also known responders to oxidative stress. In an attempt to add to the evaluation of the safety of ECIGs, metallothionein expression was quantified using the nematode Caenorhabditis elegans as an assessment of stress induced cellular damage caused by exposure. Methods: Adult nematodes were exposed to either ECIG aerosol or conventional cigarette smoke at doses of 15, 30, and 45 puffs, the equivalent of one, two, and three cigarettes, respectively. Movement, survival, and stress-induced sleep were assessed for up to 24 h after exposure. Relative expression levels for mtl-1 and mtl-2, C. elegans metallothionein genes, were analyzed after 1, 5, and 24 h post exposure using quantitative RT-PCR. Results: Nematodes exposed to conventional cigarette smoke underwent stress-induced sleep in a dose dependent manner with animals recovering to values within the range of air control after 5 h post exposure. Those exposed to ECIG aerosol did not undergo stress-induced sleep and were indistinguishable from controls. The expression of mtl-1 increased in a dose and time dependent manner in C. elegans exposed to conventional cigarette smoke, with a maximum expression observed at 5 h post exposure of 45 puffs. No induction of mtl-2 was observed in any animals. Additionally, ECIG aerosol did not induce expression of mtl-1 and mtl-2 at levels different than those of untreated. Conclusion: ECIG aerosol failed to induce a stress response in C. elegans. In contrast, conventional cigarette

Heterologous expression of a rice metallothionein isoform (OsMTI-1b) in Saccharomyces cerevisiae enhances cadmium, hydrogen peroxide and ethanol tolerance.

PubMed

Ansarypour, Zahra; Shahpiri, Azar

Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiae to Cd 2+ , H 2 O 2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing OsMTI-1b showed more tolerance to Cd 2+ and accumulated more Cd 2+ ions when they were grown in the medium containing CdCl 2 . In addition, the heterologous expression of GST-OsMTI-1b conferred H 2 O 2 and ethanol tolerance to S. cerevisiae cells. The results indicate that heterologous expression of plant MT isoforms can enhance the tolerance of S. cerevisiae to multiple stresses. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Natural genetic variation of freezing tolerance in Arabidopsis.

PubMed

Hannah, Matthew A; Wiese, Dana; Freund, Susanne; Fiehn, Oliver; Heyer, Arnd G; Hincha, Dirk K

2006-09-01

Low temperature is a primary determinant of plant growth and survival. Using accessions of Arabidopsis (Arabidopsis thaliana) originating from Scandinavia to the Cape Verde Islands, we show that freezing tolerance of natural accessions correlates with habitat winter temperatures, identifying low temperature as an important selective pressure for Arabidopsis. Combined metabolite and transcript profiling show that during cold exposure, global changes of transcripts, but not of metabolites, correlate with the ability of Arabidopsis to cold acclimate. There are, however, metabolites and transcripts, including several transcription factors, that correlate with freezing tolerance, indicating regulatory pathways that may be of primary importance for this trait. These data identify that enhanced freezing tolerance is associated with the down-regulation of photosynthesis and hormonal responses and the induction of flavonoid metabolism, provide evidence for naturally increased nonacclimated freezing tolerance due to the constitutive activation of the C-repeat binding factors pathway, and identify candidate transcriptional regulators that correlate with freezing tolerance.

Abscisic acid deficiency increases defence responses against Myzus persicae in Arabidopsis.

PubMed

Hillwig, Melissa S; Chiozza, Mariana; Casteel, Clare L; Lau, Siau Ting; Hohenstein, Jessica; Hernández, Enrique; Jander, Georg; MacIntosh, Gustavo C

2016-02-01

Comparison of Arabidopsis thaliana (Arabidopsis) gene expression induced by Myzus persicae (green peach aphid) feeding, aphid saliva infiltration and abscisic acid (ABA) treatment showed a significant positive correlation. In particular, ABA-regulated genes are over-represented among genes that are induced by M. persicae saliva infiltration into Arabidopsis leaves. This suggests that the induction of ABA-related gene expression could be an important component of the Arabidopsis-aphid interaction. Consistent with this hypothesis, M. persicae populations induced ABA production in wild-type plants. Furthermore, aphid populations were smaller on Arabidopsis aba1-1 mutants, which cannot synthesize ABA, and showed a significant preference for wild-type plants compared with the mutant. Total free amino acids, which play an important role in aphid nutrition, were not altered in the aba1-1 mutant line, but the levels of isoleucine (Ile) and tryptophan (Trp) were differentially affected by aphids in wild-type and mutant plants. Recently, indole glucosinolates have been shown to promote aphid resistance in Arabidopsis. In this study, 4-methoxyindol-3-ylmethylglucosinolate was more abundant in the aba1-1 mutant than in wild-type Arabidopsis, suggesting that the induction of ABA signals that decrease the accumulation of defence compounds may be beneficial for aphids. © 2015 BSPP AND JOHN WILEY & SONS LTD.

Relative roles of synthesis and degradation in regulating metallothionein accretion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laurin, D.E.

1989-01-01

Decay kinetics of {sup 35}S-cysteine (cys) in metallothionein (MT) were used to simultaneously measure rates of MT synthesis and degradation in a HD11 chicken-macrophage cell-line. A reverse-phase (RP) high-performance liquid-chromatography procedure was used to purify 2 MT-isoforms from cytosols with approximately 94% purity. The medium that the macrophages were incubated in was validated to ensure that it contained enough unlabeled cys to adequately chase {sup 35}S-cys released by the degradation of labeled protein. The addition of Zn{sup 2+} and unlabeled cys to the medium did not change the fractional-rates of MT synthesis (FRS) and degradation (FRD). These measurements were alsomore » validated by showing that the measured fractional-rate of MT accretion closely approximated the difference between FRS and FRD. When macrophages were incubated in medium supplemented with 50 or 25 {mu}M Zn{sup 2+} the absolute-rate of MT synthesis (ARS) and FRD increased and decreases, respectively. When macrophages were incubated in medium supplemented with 20 or 10 {mu}M Cd{sup 2+}, the ARS increased but the FDR was not changed.« less

Metallothionein turnover in mammalian cell lines: implications in drug resistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monia, B.P.; Butt, T.R.; Ecker, D.J.

1986-05-01

Metallothioneins (MT) are low molecular weight, cysteine-rich proteins believed to participate in metal detoxification. A wide variety of cells in culture have been shown to accumulate MT in response to metal administration. These metal-induced increases in MT levels result from an increased rate of MT gene transcription, MT mRNA accumulation, and MT synthesis. Turnover of Cd-, Zn- and Au-induced MT was studied in a Chinese Hamster Ovary (CHO) cell line which was resistant to Cd and the Au-containing drug Auranofin (AF). Cd, Zn and Au were potent inducers of MT mRNA and accumulated approximately equal amounts of mRNA under themore » conditions employed in this study. Pulse-chase studies utilizing (/sup 35/S)cysteine revealed that the half-life of Au-, Zn- and Cd-induced MT was 0.75, 10 and 24 hrs. respectively. The reported differences in the tertiary structure of Au-MT from that of Cd-MT lead us to propose that the differences in half-lives observed reflect differences in subceptibility to intracellular proteolysis, which in turn, may effect the ability of MT to confer resistance to various metals.« less

Genes encoding calmodulin-binding proteins in the Arabidopsis genome

NASA Technical Reports Server (NTRS)

Reddy, Vaka S.; Ali, Gul S.; Reddy, Anireddy S N.

2002-01-01

Analysis of the recently completed Arabidopsis genome sequence indicates that approximately 31% of the predicted genes could not be assigned to functional categories, as they do not show any sequence similarity with proteins of known function from other organisms. Calmodulin (CaM), a ubiquitous and multifunctional Ca(2+) sensor, interacts with a wide variety of cellular proteins and modulates their activity/function in regulating diverse cellular processes. However, the primary amino acid sequence of the CaM-binding domain in different CaM-binding proteins (CBPs) is not conserved. One way to identify most of the CBPs in the Arabidopsis genome is by protein-protein interaction-based screening of expression libraries with CaM. Here, using a mixture of radiolabeled CaM isoforms from Arabidopsis, we screened several expression libraries prepared from flower meristem, seedlings, or tissues treated with hormones, an elicitor, or a pathogen. Sequence analysis of 77 positive clones that interact with CaM in a Ca(2+)-dependent manner revealed 20 CBPs, including 14 previously unknown CBPs. In addition, by searching the Arabidopsis genome sequence with the newly identified and known plant or animal CBPs, we identified a total of 27 CBPs. Among these, 16 CBPs are represented by families with 2-20 members in each family. Gene expression analysis revealed that CBPs and CBP paralogs are expressed differentially. Our data suggest that Arabidopsis has a large number of CBPs including several plant-specific ones. Although CaM is highly conserved between plants and animals, only a few CBPs are common to both plants and animals. Analysis of Arabidopsis CBPs revealed the presence of a variety of interesting domains. Our analyses identified several hypothetical proteins in the Arabidopsis genome as CaM targets, suggesting their involvement in Ca(2+)-mediated signaling networks.

Standardized Method for High-throughput Sterilization of Arabidopsis Seeds.

PubMed

Lindsey, Benson E; Rivero, Luz; Calhoun, Chistopher S; Grotewold, Erich; Brkljacic, Jelena

2017-10-17

Arabidopsis thaliana (Arabidopsis) seedlings often need to be grown on sterile media. This requires prior seed sterilization to prevent the growth of microbial contaminants present on the seed surface. Currently, Arabidopsis seeds are sterilized using two distinct sterilization techniques in conditions that differ slightly between labs and have not been standardized, often resulting in only partially effective sterilization or in excessive seed mortality. Most of these methods are also not easily scalable to a large number of seed lines of diverse genotypes. As technologies for high-throughput analysis of Arabidopsis continue to proliferate, standardized techniques for sterilizing large numbers of seeds of different genotypes are becoming essential for conducting these types of experiments. The response of a number of Arabidopsis lines to two different sterilization techniques was evaluated based on seed germination rate and the level of seed contamination with microbes and other pathogens. The treatments included different concentrations of sterilizing agents and times of exposure, combined to determine optimal conditions for Arabidopsis seed sterilization. Optimized protocols have been developed for two different sterilization methods: bleach (liquid-phase) and chlorine (Cl2) gas (vapor-phase), both resulting in high seed germination rates and minimal microbial contamination. The utility of these protocols was illustrated through the testing of both wild type and mutant seeds with a range of germination potentials. Our results show that seeds can be effectively sterilized using either method without excessive seed mortality, although detrimental effects of sterilization were observed for seeds with lower than optimal germination potential. In addition, an equation was developed to enable researchers to apply the standardized chlorine gas sterilization conditions to airtight containers of different sizes. The protocols described here allow easy, efficient, and

Standardized Method for High-throughput Sterilization of Arabidopsis Seeds

PubMed Central

Calhoun, Chistopher S.; Grotewold, Erich; Brkljacic, Jelena

2017-01-01

Arabidopsis thaliana (Arabidopsis) seedlings often need to be grown on sterile media. This requires prior seed sterilization to prevent the growth of microbial contaminants present on the seed surface. Currently, Arabidopsis seeds are sterilized using two distinct sterilization techniques in conditions that differ slightly between labs and have not been standardized, often resulting in only partially effective sterilization or in excessive seed mortality. Most of these methods are also not easily scalable to a large number of seed lines of diverse genotypes. As technologies for high-throughput analysis of Arabidopsis continue to proliferate, standardized techniques for sterilizing large numbers of seeds of different genotypes are becoming essential for conducting these types of experiments. The response of a number of Arabidopsis lines to two different sterilization techniques was evaluated based on seed germination rate and the level of seed contamination with microbes and other pathogens. The treatments included different concentrations of sterilizing agents and times of exposure, combined to determine optimal conditions for Arabidopsis seed sterilization. Optimized protocols have been developed for two different sterilization methods: bleach (liquid-phase) and chlorine (Cl2) gas (vapor-phase), both resulting in high seed germination rates and minimal microbial contamination. The utility of these protocols was illustrated through the testing of both wild type and mutant seeds with a range of germination potentials. Our results show that seeds can be effectively sterilized using either method without excessive seed mortality, although detrimental effects of sterilization were observed for seeds with lower than optimal germination potential. In addition, an equation was developed to enable researchers to apply the standardized chlorine gas sterilization conditions to airtight containers of different sizes. The protocols described here allow easy, efficient, and

Synteny conservation between the Prunus genome and both the present and ancestral Arabidopsis genomes

PubMed Central

Jung, Sook; Main, Dorrie; Staton, Margaret; Cho, Ilhyung; Zhebentyayeva, Tatyana; Arús, Pere; Abbott, Albert

2006-01-01

Background Due to the lack of availability of large genomic sequences for peach or other Prunus species, the degree of synteny conservation between the Prunus species and Arabidopsis has not been systematically assessed. Using the recently available peach EST sequences that are anchored to Prunus genetic maps and to peach physical map, we analyzed the extent of conserved synteny between the Prunus and the Arabidopsis genomes. The reconstructed pseudo-ancestral Arabidopsis genome, existed prior to the proposed recent polyploidy event, was also utilized in our analysis to further elucidate the evolutionary relationship. Results We analyzed the synteny conservation between the Prunus and the Arabidopsis genomes by comparing 475 peach ESTs that are anchored to Prunus genetic maps and their Arabidopsis homologs detected by sequence similarity. Microsyntenic regions were detected between all five Arabidopsis chromosomes and seven of the eight linkage groups of the Prunus reference map. An additional 1097 peach ESTs that are anchored to 431 BAC contigs of the peach physical map and their Arabidopsis homologs were also analyzed. Microsyntenic regions were detected in 77 BAC contigs. The syntenic regions from both data sets were short and contained only a couple of conserved gene pairs. The synteny between peach and Arabidopsis was fragmentary; all the Prunus linkage groups containing syntenic regions matched to more than two different Arabidopsis chromosomes, and most BAC contigs with multiple conserved syntenic regions corresponded to multiple Arabidopsis chromosomes. Using the same peach EST datasets and their Arabidopsis homologs, we also detected conserved syntenic regions in the pseudo-ancestral Arabidopsis genome. In many cases, the gene order and content of peach regions was more conserved in the ancestral genome than in the present Arabidopsis region. Statistical significance of each syntenic group was calculated using simulated Arabidopsis genome. Conclusion We

Regulation of planar growth by the Arabidopsis AGC protein kinase UNICORN.

PubMed

Enugutti, Balaji; Kirchhelle, Charlotte; Oelschner, Maxi; Torres Ruiz, Ramón Angel; Schliebner, Ivo; Leister, Dario; Schneitz, Kay

2012-09-11

The spatial coordination of growth is of central importance for the regulation of plant tissue architecture. Individual layers, such as the epidermis, are clonally propagated and structurally maintained by symmetric cell divisions that are oriented along the plane of the layer. The developmental control of this process is poorly understood. The simple cellular basis and sheet-like structure of Arabidopsis integuments make them an attractive model system to address planar growth. Here we report on the characterization of the Arabidopsis UNICORN (UCN) gene. Analysis of ucn integuments reveals localized distortion of planar growth, eventually resulting in an ectopic multicellular protrusion. In addition, ucn mutants exhibit ectopic growth in filaments and petals, as well as aberrant embryogenesis. We further show that UCN encodes an active AGC VIII kinase. Genetic, biochemical, and cell biological data suggest that UCN suppresses ectopic growth in integuments by directly repressing the KANADI transcription factor ABERRANT TESTA SHAPE. Our findings indicate that UCN represents a unique plant growth regulator that maintains planar growth of integuments by repressing a developmental regulator involved in the control of early integument growth and polarity.

Arabidopsis gene expression patterns are altered during spaceflight

NASA Astrophysics Data System (ADS)

Paul, Anna-Lisa; Popp, Michael P.; Gurley, William B.; Guy, Charles; Norwood, Kelly L.; Ferl, Robert J.

The exposure of Arabidopsis thaliana (Arabidopsis) plants to spaceflight environments results in differential gene expression. A 5-day mission on orbiter Columbia in 1999 (STS-93) carried transgenic Arabidopsis plants engineered with a transgene composed of the alcohol dehydrogenase (Adh) gene promoter linked to the β-Glucuronidase (GUS) reporter gene. The plants were used to evaluate the effects of spaceflight on gene expression patterns initially by using the Adh/GUS transgene to address specifically the possibility that spaceflight induces a hypoxic stress response (Paul, A.L., Daugherty, C.J., Bihn, E.A., Chapman, D.K., Norwood, K.L., Ferl, R.J., 2001. Transgene expression patterns indicate that spaceflight affects stress signal perception and transduction in arabidopsis, Plant Physiol. 126, 613-621). As a follow-on to the reporter gene analysis, we report here the evaluation of genome-wide patterns of native gene expression within Arabidopsis shoots utilizing the Agilent DNA array of 21,000 Arabidopsis genes. As a control for the veracity of the array analyses, a selection of genes was further characterized with quantitative Real-Time RT PCR (ABI - Taqman®). Comparison of the patterns of expression for arrays probed with RNA isolated from plants exposed to spaceflight compared to RNA isolated from ground control plants revealed 182 genes that were differentially expressed in response to the spaceflight mission by more than 4-fold, and of those only 50 genes were expressed at levels chosen to support a conservative change call. None of the genes that are hallmarks of hypoxic stress were induced to this level. However, genes related to heat shock were dramatically induced - but in a pattern and under growth conditions that are not easily explained by elevated temperatures. These gene expression data are discussed in light of current models for plant responses to the spaceflight environment and with regard to potential future spaceflight experiment

Phytoplasma Effector SAP54 Induces Indeterminate Leaf-Like Flower Development in Arabidopsis Plants1[C][W][OA

PubMed Central

MacLean, Allyson M.; Sugio, Akiko; Makarova, Olga V.; Findlay, Kim C.; Grieve, Victoria M.; Tóth, Réka; Nicolaisen, Mogens; Hogenhout, Saskia A.

2011-01-01

Phytoplasmas are insect-transmitted bacterial plant pathogens that cause considerable damage to a diverse range of agricultural crops globally. Symptoms induced in infected plants suggest that these phytopathogens may modulate developmental processes within the plant host. We report herein that Aster Yellows phytoplasma strain Witches’ Broom (AY-WB) readily infects the model plant Arabidopsis (Arabidopsis thaliana) ecotype Columbia, inducing symptoms that are characteristic of phytoplasma infection, such as the production of green leaf-like flowers (virescence and phyllody) and increased formation of stems and branches (witches’ broom). We found that the majority of genes encoding secreted AY-WB proteins (SAPs), which are candidate effector proteins, are expressed in Arabidopsis and the AY-WB insect vector Macrosteles quadrilineatus (Hemiptera; Cicadellidae). To identify which of these effector proteins induce symptoms of phyllody and virescence, we individually expressed the effector genes in Arabidopsis. From this screen, we have identified a novel AY-WB effector protein, SAP54, that alters floral development, resulting in the production of leaf-like flowers that are similar to those produced by plants infected with this phytoplasma. This study offers novel insight into the effector profile of an insect-transmitted plant pathogen and reports to our knowledge the first example of a microbial pathogen effector protein that targets flower development in a host. PMID:21849514

Arabidopsis gene expression patterns during spaceflight

NASA Astrophysics Data System (ADS)

Paul, A.-L.; Ferl, R. J.

The exposure of Arabidopsis thaliana (Arabidopsis) plants to spaceflight environments resulted in the differential expression of hundreds of genes. A 5 day mission on orbiter Columbia in 1999 (STS-93) carried transgenic Arabidopsis plants engineered with a transgene composed of the alcohol dehydrogenase (Adh) gene promoter linked to the β -Glucuronidase (GUS) reporter gene. The plants were used to evaluate the effects of spaceflight on two fronts. First, expression patterns visualized with the Adh/GUS transgene were used to address specifically the possibility that spaceflight induces a hypoxic stress response, and to assess whether any spaceflight response was similar to control terrestrial hypoxia-induced gene expression patterns. (Paul et al., Plant Physiol. 2001, 126:613). Second, genome-wide patterns of native gene expression were evaluated utilizing the Affymetrix ATH1 GeneChip? array of 8,000 Arabidopsis genes. As a control for the veracity of the array analyses, a selection of genes identified with the arrays was further characterized with quantitative Real-Time RT PCR (ABI - TaqmanTM). Comparison of the patterns of expression for arrays of hybridized with RNA isolated from plants exposed to spaceflight compared to the control arrays revealed hundreds of genes that were differentially expressed in response to spaceflight, yet most genes that are hallmarks of hypoxic stress were unaffected. These results will be discussed in light of current models for plant responses to the spaceflight environment, and with regard to potential future flight opportunities.

50 years of Arabidopsis research: highlights and future directions

DOE PAGES

Provart, Nicholas J.; Alonso, Jose; Assmann, Sarah M.; ...

2015-10-14

The year 2014 marked the 25 th International Conference on Arabidopsis Research. In the 50 yr since the first International Conference on Arabidopsis Research, held in 1965 in Göttingen, Germany, > 54 000 papers that mention Arabidopsis thaliana in the title, abstract or keywords have been published. In this paper, we present herein a citational network analysis of these papers, and touch on some of the important discoveries in plant biology that have been made in this powerful model system, and highlight how these discoveries have then had an impact in crop species. We also look to the future, highlightingmore » some outstanding questions that can be readily addressed in Arabidopsis. Topics that are discussed include Arabidopsis reverse genetic resources, stock centers, databases and online tools, cell biology, development, hormones, plant immunity, signaling in response to abiotic stress, transporters, biosynthesis of cells walls and macromolecules such as starch and lipids, epigenetics and epigenomics, genome-wide association studies and natural variation, gene regulatory networks, modeling and systems biology, and synthetic biology.« less

50 years of Arabidopsis research: highlights and future directions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Provart, Nicholas J.; Alonso, Jose; Assmann, Sarah M.

The year 2014 marked the 25 th International Conference on Arabidopsis Research. In the 50 yr since the first International Conference on Arabidopsis Research, held in 1965 in Göttingen, Germany, > 54 000 papers that mention Arabidopsis thaliana in the title, abstract or keywords have been published. In this paper, we present herein a citational network analysis of these papers, and touch on some of the important discoveries in plant biology that have been made in this powerful model system, and highlight how these discoveries have then had an impact in crop species. We also look to the future, highlightingmore » some outstanding questions that can be readily addressed in Arabidopsis. Topics that are discussed include Arabidopsis reverse genetic resources, stock centers, databases and online tools, cell biology, development, hormones, plant immunity, signaling in response to abiotic stress, transporters, biosynthesis of cells walls and macromolecules such as starch and lipids, epigenetics and epigenomics, genome-wide association studies and natural variation, gene regulatory networks, modeling and systems biology, and synthetic biology.« less

Submergence Confers Immunity Mediated by the WRKY22 Transcription Factor in Arabidopsis[W

PubMed Central

Hsu, Fu-Chiun; Chou, Mei-Yi; Chou, Shu-Jen; Li, Ya-Ru; Peng, Hsiao-Ping; Shih, Ming-Che

2013-01-01

Transcriptional control plays an important role in regulating submergence responses in plants. Although numerous genes are highly induced during hypoxia, their individual roles in hypoxic responses are still poorly understood. Here, we found that expression of genes that encode members of the WRKY transcription factor family was rapidly and strongly induced upon submergence in Arabidopsis thaliana, and this induction correlated with induction of a large portion of innate immunity marker genes. Furthermore, prior submergence treatment conferred higher resistance to the bacterial pathogen Pseudomonas syringae in Arabidopsis. Among the WRKY genes tested, WRKY22 had the highest level of induction during the early stages of submergence. Compared with the wild type, WRKY22 T-DNA insertion mutants wrky22-1 and wrky22-2 had lower disease resistance and lower induction of innate immunity markers, such as FLG22-INDUCED RECEPTOR-LIKE KINASE1 (FRK1) and WRKY53, after submergence. Furthermore, transcriptomic analyses of wrky22-2 and chromatin immunoprecipitation identified several potential targets of WRKY22, which included genes encoding a TIR domain–containing protein, a plant peptide hormone, and many OLIGO PEPTIDE TRANSPORTER genes, all of which may lead to induction of innate immunity. In conclusion, we propose that submergence triggers innate immunity in Arabidopsis via WRKY22, a response that may protect against a higher probability of pathogen infection either during or after flooding. PMID:23897923

Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes.

PubMed

Riechmann, J L; Heard, J; Martin, G; Reuber, L; Jiang, C; Keddie, J; Adam, L; Pineda, O; Ratcliffe, O J; Samaha, R R; Creelman, R; Pilgrim, M; Broun, P; Zhang, J Z; Ghandehari, D; Sherman, B K; Yu, G

2000-12-15

The completion of the Arabidopsis thaliana genome sequence allows a comparative analysis of transcriptional regulators across the three eukaryotic kingdoms. Arabidopsis dedicates over 5% of its genome to code for more than 1500 transcription factors, about 45% of which are from families specific to plants. Arabidopsis transcription factors that belong to families common to all eukaryotes do not share significant similarity with those of the other kingdoms beyond the conserved DNA binding domains, many of which have been arranged in combinations specific to each lineage. The genome-wide comparison reveals the evolutionary generation of diversity in the regulation of transcription.

Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks

DTIC Science & Technology

2012-09-21

Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks Paulo Shakarian1*, J. Kenneth Wickiser2 1 Paulo Shakarian...significantly attacked. Citation: Shakarian P, Wickiser JK (2012) Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks...to 00-00-2012 4. TITLE AND SUBTITLE Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks 5a. CONTRACT NUMBER 5b

Transcriptional analysis of the Arabidopsis ovule by massively parallel signature sequencing.

PubMed

Sánchez-León, Nidia; Arteaga-Vázquez, Mario; Alvarez-Mejía, César; Mendiola-Soto, Javier; Durán-Figueroa, Noé; Rodríguez-Leal, Daniel; Rodríguez-Arévalo, Isaac; García-Campayo, Vicenta; García-Aguilar, Marcelina; Olmedo-Monfil, Vianey; Arteaga-Sánchez, Mario; de la Vega, Octavio Martínez; Nobuta, Kan; Vemaraju, Kalyan; Meyers, Blake C; Vielle-Calzada, Jean-Philippe

2012-06-01

The life cycle of flowering plants alternates between a predominant sporophytic (diploid) and an ephemeral gametophytic (haploid) generation that only occurs in reproductive organs. In Arabidopsis thaliana, the female gametophyte is deeply embedded within the ovule, complicating the study of the genetic and molecular interactions involved in the sporophytic to gametophytic transition. Massively parallel signature sequencing (MPSS) was used to conduct a quantitative large-scale transcriptional analysis of the fully differentiated Arabidopsis ovule prior to fertilization. The expression of 9775 genes was quantified in wild-type ovules, additionally detecting >2200 new transcripts mapping to antisense or intergenic regions. A quantitative comparison of global expression in wild-type and sporocyteless (spl) individuals resulted in 1301 genes showing 25-fold reduced or null activity in ovules lacking a female gametophyte, including those encoding 92 signalling proteins, 75 transcription factors, and 72 RNA-binding proteins not reported in previous studies based on microarray profiling. A combination of independent genetic and molecular strategies confirmed the differential expression of 28 of them, showing that they are either preferentially active in the female gametophyte, or dependent on the presence of a female gametophyte to be expressed in sporophytic cells of the ovule. Among 18 genes encoding pentatricopeptide-repeat proteins (PPRs) that show transcriptional activity in wild-type but not spl ovules, CIHUATEOTL (At4g38150) is specifically expressed in the female gametophyte and necessary for female gametogenesis. These results expand the nature of the transcriptional universe present in the ovule of Arabidopsis, and offer a large-scale quantitative reference of global expression for future genomic and developmental studies.

Stochastic gene expression in Arabidopsis thaliana.

PubMed

Araújo, Ilka Schultheiß; Pietsch, Jessica Magdalena; Keizer, Emma Mathilde; Greese, Bettina; Balkunde, Rachappa; Fleck, Christian; Hülskamp, Martin

2017-12-14

Although plant development is highly reproducible, some stochasticity exists. This developmental stochasticity may be caused by noisy gene expression. Here we analyze the fluctuation of protein expression in Arabidopsis thaliana. Using the photoconvertible KikGR marker, we show that the protein expressions of individual cells fluctuate over time. A dual reporter system was used to study extrinsic and intrinsic noise of marker gene expression. We report that extrinsic noise is higher than intrinsic noise and that extrinsic noise in stomata is clearly lower in comparison to several other tissues/cell types. Finally, we show that cells are coupled with respect to stochastic protein expression in young leaves, hypocotyls and roots but not in mature leaves. Our data indicate that stochasticity of gene expression can vary between tissues/cell types and that it can be coupled in a non-cell-autonomous manner.

High throughput selection of antibiotic-resistant transgenic Arabidopsis plants.

PubMed

Nagashima, Yukihiro; Koiwa, Hisashi

2017-05-15

Kanamycin resistance is the most frequently used antibiotic-resistance marker for Arabidopsis transformations, however, this method frequently causes escape of untransformed plants, particularly at the high seedling density during the selection. Here we developed a robust high-density selection method using top agar for Arabidopsis thaliana. Top agar effectively suppressed growth of untransformed wild-type plants on selection media at high density. Survival of the transformed plants during the selection were confirmed by production of green true leaves and expression of a firefly luciferase reporter gene. Top agar method allowed selection using a large amount of seeds in Arabidopsis transformation. Copyright © 2017 Elsevier Inc. All rights reserved.

Deletion of metallothionein exacerbates intermittent hypoxia-induced oxidative and inflammatory injury in aorta.

PubMed

Zhou, Shanshan; Wang, Yonggang; Tan, Yi; Cai, Xiaohong; Cai, Lu; Cai, Jun; Zheng, Yang

2014-01-01

The present study was to explore the effect of metallothionein (MT) on intermittent hypoxia (IH) induced aortic pathogenic changes. Markers of oxidative damages, inflammation, and vascular remodeling were observed by immunohistochemical staining after 3 days and 1, 3, and 8 weeks after IH exposures. Endogenous MT was induced after 3 days of IH but was significantly decreased after 8 weeks of IH. Compared with the wild-type mice, MT knock-out mice exhibited earlier and more severe pathogenic changes of oxidative damages, inflammatory responses, and cellular apoptosis, as indicated by the significant accumulation of collagen, increased levels of connective tissue growth factor, transforming growth factor β1, tumor necrosis factor-alpha, vascular cell adhesion molecule 1,3-nitrotyrosine, and 4-hydroxy-2-nonenal in the aorta. These findings suggested that chronic IH may lead to aortic damages characterized by oxidative stress and inflammation, and MT may play a pivotal role in the above pathogenesis process.

Polyphenol-rich beverages enhance zinc uptake and metallothionein expression in Caco-2 cells.

PubMed

Sreenivasulu, Kilari; Raghu, Pullakhandam; Nair, K Madhavan

2010-05-01

The effect of red wine (RW), red grape juice (RGJ), green tea (GT), and representative polyphenols on Caco-2 cell (65)Zn uptake was explored. RW, RGJ, and GT enhanced the uptake of zinc from rice matrix. Fractionation of RW revealed that enhancing activity of zinc uptake was exclusively resided in the polyphenol fraction. Among the polyphenols tested, only tannic acid and quercitin stimulated the uptake of zinc while others did not influence the uptake. In tune with these results, only tannic acid and quercitin competed with zinquin (a zinc selective fluorophore) for zinc in vitro. Although all the polyphenols tested appear to enhance the expression of metallothionein (MT), the induction was higher with tannic acid, quercitin, and RW extract. Furthermore, phytic acid abrogated the tannic acid-induced MT expression. These results suggest that polyphenol-rich beverages, tannic acid, and quercitin bind and stimulate the zinc uptake and MT expression in Caco-2 cells.

50 years of Arabidopsis research: highlights and future directions.

PubMed

Provart, Nicholas J; Alonso, Jose; Assmann, Sarah M; Bergmann, Dominique; Brady, Siobhan M; Brkljacic, Jelena; Browse, John; Chapple, Clint; Colot, Vincent; Cutler, Sean; Dangl, Jeff; Ehrhardt, David; Friesner, Joanna D; Frommer, Wolf B; Grotewold, Erich; Meyerowitz, Elliot; Nemhauser, Jennifer; Nordborg, Magnus; Pikaard, Craig; Shanklin, John; Somerville, Chris; Stitt, Mark; Torii, Keiko U; Waese, Jamie; Wagner, Doris; McCourt, Peter

2016-02-01

922 I. 922 II. 922 III. 925 IV. 925 V. 926 VI. 927 VII. 928 VIII. 929 IX. 930 X. 931 XI. 932 XII. 933 XIII. Natural variation and genome-wide association studies 934 XIV. 934 XV. 935 XVI. 936 XVII. 937 937 References 937 SUMMARY: The year 2014 marked the 25(th) International Conference on Arabidopsis Research. In the 50 yr since the first International Conference on Arabidopsis Research, held in 1965 in Göttingen, Germany, > 54 000 papers that mention Arabidopsis thaliana in the title, abstract or keywords have been published. We present herein a citational network analysis of these papers, and touch on some of the important discoveries in plant biology that have been made in this powerful model system, and highlight how these discoveries have then had an impact in crop species. We also look to the future, highlighting some outstanding questions that can be readily addressed in Arabidopsis. Topics that are discussed include Arabidopsis reverse genetic resources, stock centers, databases and online tools, cell biology, development, hormones, plant immunity, signaling in response to abiotic stress, transporters, biosynthesis of cells walls and macromolecules such as starch and lipids, epigenetics and epigenomics, genome-wide association studies and natural variation, gene regulatory networks, modeling and systems biology, and synthetic biology. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Does Variation of the Inter-Domain Linker Sequence Modulate the Metal Binding Behaviour of Helix pomatia Cd-Metallothionein?

PubMed Central

Gil-Moreno, Selene; Jiménez-Martí, Elena; Palacios, Òscar; Zerbe, Oliver; Dallinger, Reinhard; Capdevila, Mercè; Atrian, Sílvia

2015-01-01

Snail metallothioneins (MTs) constitute an ideal model to study structure/function relationships in these metal-binding polypeptides. Helix pomatia harbours three MT isoforms: the highly specific CdMT and CuMT, and an unspecific Cd/CuMT, which represent paralogous proteins with extremely different metal binding preferences while sharing high sequence similarity. Preceding work allowed assessing that, although, the Cys residues are responsible for metal ion coordination, metal specificity or preference is achieved by diversification of the amino acids interspersed between them. The metal-specific MT polypeptides fold into unique, energetically-optimized complexes of defined metal content, when binding their cognate metal ions, while they produce a mixture of complexes, none of them representing a clear energy minimum, with non-cognate metal ions. Another critical, and so far mostly unexplored, region is the stretch linking the individual MT domains, each of which represents an independent metal cluster. In this work, we have designed and analyzed two HpCdMT constructs with substituted linker segments, and determined their coordination behavior when exposed to both cognate and non-cognate metal ions. Results unequivocally show that neither length nor composition of the inter-domain linker alter the features of the Zn(II)- and Cd(II)-complexes, but surprisingly that they influence their ability to bind Cu(I), the non-cognate metal ion. PMID:26703589

Soil mixture composition alters Arabidopsis susceptibility to Pseudomonas syringae infection

USDA-ARS?s Scientific Manuscript database

Pseudomonas syringae is a Gram-negative bacterial pathogen that causes disease on more than 100 different plant species, including the model plant Arabidopsis thaliana. Dissection of the Arabidopsis thaliana-Pseudomonas syringae pathosystem has identified many factors that contribute to successful ...

Adsorption and inhibition of CuO nanoparticles on Arabidopsis thaliana root

NASA Astrophysics Data System (ADS)

Xu, Lina

2018-02-01

CuO NPs, the size ranging from 20 to 80 nm were used to detect the adsorption and inhibition on the Arabidopsis thaliana roots. In this study, CuO NPs were adsorbed and agglomerated on the surface of root top after exposed for 7 days. With the increasing of CuO NPs concentrations, CuO NPs also adsorbed on the meristernatic zone. The growth of Arabidopsis thaliana lateral roots were also inhibited by CuO NPs exposure. The Inhibition were concentration dependent. The number of root top were 246, 188 and 123 per Arabidopsis thaliana, respectively. The number of root tops after CuO NPs exposure were significantly decreased compared with control groups. This results suggested the phytotoxicity of CuO NPs on Arabidopsis thaliana roots.

Arabidopsis Defense against Botrytis cinerea: Chronology and Regulation Deciphered by High-Resolution Temporal Transcriptomic Analysis[C][W

PubMed Central

Windram, Oliver; Madhou, Priyadharshini; McHattie, Stuart; Hill, Claire; Hickman, Richard; Cooke, Emma; Jenkins, Dafyd J.; Penfold, Christopher A.; Baxter, Laura; Breeze, Emily; Kiddle, Steven J.; Rhodes, Johanna; Atwell, Susanna; Kliebenstein, Daniel J.; Kim, Youn-sung; Stegle, Oliver; Borgwardt, Karsten; Zhang, Cunjin; Tabrett, Alex; Legaie, Roxane; Moore, Jonathan; Finkenstadt, Bärbel; Wild, David L.; Mead, Andrew; Rand, David; Beynon, Jim; Ott, Sascha; Buchanan-Wollaston, Vicky; Denby, Katherine J.

2012-01-01

Transcriptional reprogramming forms a major part of a plant’s response to pathogen infection. Many individual components and pathways operating during plant defense have been identified, but our knowledge of how these different components interact is still rudimentary. We generated a high-resolution time series of gene expression profiles from a single Arabidopsis thaliana leaf during infection by the necrotrophic fungal pathogen Botrytis cinerea. Approximately one-third of the Arabidopsis genome is differentially expressed during the first 48 h after infection, with the majority of changes in gene expression occurring before significant lesion development. We used computational tools to obtain a detailed chronology of the defense response against B. cinerea, highlighting the times at which signaling and metabolic processes change, and identify transcription factor families operating at different times after infection. Motif enrichment and network inference predicted regulatory interactions, and testing of one such prediction identified a role for TGA3 in defense against necrotrophic pathogens. These data provide an unprecedented level of detail about transcriptional changes during a defense response and are suited to systems biology analyses to generate predictive models of the gene regulatory networks mediating the Arabidopsis response to B. cinerea. PMID:23023172

Arabidopsis Response Regulator1 and Arabidopsis Histidine Phosphotransfer Protein2 (AHP2), AHP3, and AHP5 Function in Cold Signaling1[W][OA

PubMed Central

Jeon, Jin; Kim, Jungmook

2013-01-01

The Arabidopsis (Arabidopsis thaliana) two-component signaling system, which is composed of sensor histidine kinases, histidine phosphotransfer proteins, and response regulators, mediates the cytokinin response and various other plant responses. We have previously shown that ARABIDOPSIS HISTIDINE KINASE2 (AHK2), AHK3, and cold-inducible type A ARABIDOPSIS RESPONSE REGULATORS (ARRs) play roles in cold signaling. However, the roles of type B ARRs and ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEINS (AHPs) have not been investigated in cold signaling. Here, we show that ARR1 and AHP2, AHP3, and AHP5 play positive roles in the cold-inducible expression of type A ARRs. arr1 mutants showed greatly reduced cold-responsive expression of type A ARRs compared with the wild type, whereas ARR1-overexpressing Arabidopsis exhibited the hypersensitive cold response of type A ARRs as well as enhanced freezing tolerance with cytokinin, suggesting that ARR1 functions as a positive factor of cold signaling. Transgenic Arabidopsis expressing ARR1ΔDDK:GR lacking the amino-terminal receiver domain showed wild-type expression levels of type A ARRs in response to cold, indicating that the signal receiver domain of ARR1 might be important for cold-responsive expression of type A ARRs. ahp2 ahp3 ahp5 triple mutations greatly reduced type A ARR expression in response to cold, whereas the single or double ahp mutants displayed wild-type levels of ARR expression, suggesting that AHP2, AHP3, and AHP5 are redundantly involved in cold signaling. Taken together, these results suggest that ARR1 mediates cold signal via AHP2, AHP3, or AHP5 from AHK2 and AHK3 to express type A ARRs. We further identified a cold transcriptome affected by ahk2 ahk3 mutations by microarray analysis, revealing a new cold-responsive gene network regulated downstream of AHK2 and AHK3. PMID:23124324

Transcription factor MBF-I interacts with metal regulatory elements of higher eucaryotic metallothionein genes.

PubMed Central

Imbert, J; Zafarullah, M; Culotta, V C; Gedamu, L; Hamer, D

1989-01-01

Metallothionein (MT) gene promoters in higher eucaryotes contain multiple metal regulatory elements (MREs) that are responsible for the metal induction of MT gene transcription. We identified and purified to near homogeneity a 74-kilodalton mouse nuclear protein that specifically binds to certain MRE sequences. This protein, MBF-I, was purified employing as an affinity reagent a trout MRE that is shown to be functional in mouse cells but which lacks the G+C-rich and SP1-like sequences found in many mammalian MT gene promoters. Using point-mutated MREs, we showed that there is a strong correlation between DNA binding in vitro and MT gene regulation in vivo, suggesting a direct role of MBF-I in MT gene transcription. We also showed that MBF-I can induce MT gene transcription in vitro in a mouse extract and that this stimulation requires zinc. Images PMID:2586522

Regulatory Proteolysis in Arabidopsis-Pathogen Interactions.

PubMed

Pogány, Miklós; Dankó, Tamás; Kámán-Tóth, Evelin; Schwarczinger, Ildikó; Bozsó, Zoltán

2015-09-24

Approximately two and a half percent of protein coding genes in Arabidopsis encode enzymes with known or putative proteolytic activity. Proteases possess not only common housekeeping functions by recycling nonfunctional proteins. By irreversibly cleaving other proteins, they regulate crucial developmental processes and control responses to environmental changes. Regulatory proteolysis is also indispensable in interactions between plants and their microbial pathogens. Proteolytic cleavage is simultaneously used both by plant cells, to recognize and inactivate invading pathogens, and by microbes, to overcome the immune system of the plant and successfully colonize host cells. In this review, we present available results on the group of proteases in the model plant Arabidopsis thaliana whose functions in microbial pathogenesis were confirmed. Pathogen-derived proteolytic factors are also discussed when they are involved in the cleavage of host metabolites. Considering the wealth of review papers available in the field of the ubiquitin-26S proteasome system results on the ubiquitin cascade are not presented. Arabidopsis and its pathogens are conferred with abundant sets of proteases. This review compiles a list of those that are apparently involved in an interaction between the plant and its pathogens, also presenting their molecular partners when available.

Expression of a nitric oxide degrading enzyme induces a senescence programme in Arabidopsis.

PubMed

Mishina, Tatiana E; Lamb, Chris; Zeier, Jürgen

2007-01-01

Nitric oxide (NO) has been proposed to act as a factor delaying leaf senescence and fruit maturation in plants. Here we show that expression of a NO degrading dioxygenase (NOD) in Arabidopsis thaliana initiates a senescence-like phenotype, an effect that proved to be more pronounced in older than in younger leaves. This senescence phenotype was preceded by a massive switch in gene expression in which photosynthetic genes were down-regulated, whereas many senescence-associated genes (SAGs) and the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase gene ACS6 involved in ethylene synthesis were up-regulated. External fumigation of NOD plants with NO as well as environmental conditions known to stimulate endogenous NO production attenuated the induced senescence programme. For instance, both high light conditions and nitrate feeding reduced the senescence phenotype and attenuated the down-regulation of photosynthetic genes as well as the up-regulation of SAGs. Treatment of plants with the cytokinin 6-benzylaminopurin (BAP) reduced the down-regulation of photosynthesis, although it had no consistent effect on SAG expression. Metabolic changes during NOD-induced senescence comprehended increases in salicylic acid (SA) levels, accumulation of the phytoalexin camalexin and elevation of leaf gamma-tocopherol contents, all of which occurred during natural senescence in Arabidopsis leaves as well. Moreover, NO fumigation delayed the senescence process induced by darkening individual Arabidopsis Columbia-0 (Col-0) leaves. Our data thus support the notion that NO acts as a negative regulator of leaf senescence.

Transcriptional analysis of the Arabidopsis ovule by massively parallel signature sequencing

PubMed Central

Sánchez-León, Nidia; Arteaga-Vázquez, Mario; Alvarez-Mejía, César; Mendiola-Soto, Javier; Durán-Figueroa, Noé; Rodríguez-Leal, Daniel; Rodríguez-Arévalo, Isaac; García-Campayo, Vicenta; García-Aguilar, Marcelina; Olmedo-Monfil, Vianey; Arteaga-Sánchez, Mario; Martínez de la Vega, Octavio; Nobuta, Kan; Vemaraju, Kalyan; Meyers, Blake C.; Vielle-Calzada, Jean-Philippe

2012-01-01

The life cycle of flowering plants alternates between a predominant sporophytic (diploid) and an ephemeral gametophytic (haploid) generation that only occurs in reproductive organs. In Arabidopsis thaliana, the female gametophyte is deeply embedded within the ovule, complicating the study of the genetic and molecular interactions involved in the sporophytic to gametophytic transition. Massively parallel signature sequencing (MPSS) was used to conduct a quantitative large-scale transcriptional analysis of the fully differentiated Arabidopsis ovule prior to fertilization. The expression of 9775 genes was quantified in wild-type ovules, additionally detecting >2200 new transcripts mapping to antisense or intergenic regions. A quantitative comparison of global expression in wild-type and sporocyteless (spl) individuals resulted in 1301 genes showing 25-fold reduced or null activity in ovules lacking a female gametophyte, including those encoding 92 signalling proteins, 75 transcription factors, and 72 RNA-binding proteins not reported in previous studies based on microarray profiling. A combination of independent genetic and molecular strategies confirmed the differential expression of 28 of them, showing that they are either preferentially active in the female gametophyte, or dependent on the presence of a female gametophyte to be expressed in sporophytic cells of the ovule. Among 18 genes encoding pentatricopeptide-repeat proteins (PPRs) that show transcriptional activity in wild-type but not spl ovules, CIHUATEOTL (At4g38150) is specifically expressed in the female gametophyte and necessary for female gametogenesis. These results expand the nature of the transcriptional universe present in the ovule of Arabidopsis, and offer a large-scale quantitative reference of global expression for future genomic and developmental studies. PMID:22442422

CRISPR/Cas9-mediated gene targeting in Arabidopsis using sequential transformation.

PubMed

Miki, Daisuke; Zhang, Wenxin; Zeng, Wenjie; Feng, Zhengyan; Zhu, Jian-Kang

2018-05-17

Homologous recombination-based gene targeting is a powerful tool for precise genome modification and has been widely used in organisms ranging from yeast to higher organisms such as Drosophila and mouse. However, gene targeting in higher plants, including the most widely used model plant Arabidopsis thaliana, remains challenging. Here we report a sequential transformation method for gene targeting in Arabidopsis. We find that parental lines expressing the bacterial endonuclease Cas9 from the egg cell- and early embryo-specific DD45 gene promoter can improve the frequency of single-guide RNA-targeted gene knock-ins and sequence replacements via homologous recombination at several endogenous sites in the Arabidopsis genome. These heritable gene targeting can be identified by regular PCR. Our approach enables routine and fine manipulation of the Arabidopsis genome.

Zinc and dexamethasone induce metallothionein accumulation by endothelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Briske-Anderson, M.; Bobilya, D.J.; Reeves, P.G.

1991-03-11

Several tissues increase their metallothionein (MT) concentration when exposed to elevated amounts of plasma Zn. Endothelial cells form the blood vessels that supply all tissues and constitute a barrier between cells of tissues and the blood. This study examined the ability of endothelial cells to synthesize MT and accumulate Zn in response to high amounts of Zn and dexamethasone. Bovine pulmonary endothelial cells were grown to confluence in Minimum Essential Medium with Earle's salts and 10% fetal calf serum. The monolayer was maintained for 2 d prior to use in medium containing EDTA-dialyzed serum. This low Zn medium was replacedmore » with one containing 1, 6, 25, 50, 100, 150, or 200 {mu}M Zn and incubated for 24 hr before harvesting the cells. MT was quantified by the cadmium binding assay. Cellular Zn concentrations were analyzed by atomic absorption after a nitric acid digestion. The MT concentration was elevated in response to Zn concentrations of 100 {mu}M or more. Cellular Zn concentration was elevated when media Zn was 25 {mu}M or more. MT and cellular Zn concentrations were positively correlated. In another study, inclusion of 0.1 {mu}M dexamethasone in the media increased concentration at all Zn concentrations studied. However, the inclusion of 0.3 {mu}M cis-platinum had no effect. In conclusion, endothelial cells in culture respond to elevated amounts of Zn and dexamethasone in the media by accumulating Zn and MT.« less

The role of metallothionein in oncogenesis and cancer treatment.

PubMed

Bizoń, Anna; Jędryczko, Kinga; Milnerowicz, Halina

2017-02-14

Metallothionein is cysteine-rich low molecular mass protein. The involvement of MT in many physiological and pathophysiological processes such as apoptosis, proliferation, angiogenesis, and the detoxification of heavy metals suggested participation of this protein in carcinogenesis and tumor therapy. Depending on the type of tissue and classification of carcinoma various it was observed relation between MT expression and tumor type, stage, grade, poor prognosis and body resistance to radiotherapy and chemotherapy. MT in tumor cell plays important role in defense mechanism against the effect of radiation by inhibiting the processes that lead to the apoptosis. A number of studies have shown an increased expression of MT in various human tumors of larynx, pancreas, kidney, uterus and breast, whereas lower MT expression was detected in liver tumors. Variable MT expression was detected in case of thyroid, prostate, lung, stomach and central nervous system tumors. Also MT plays crucial role in the cytostatics treatment. MT can bind cis-platinum compounds and removes them from the cells, which may lead to multidrug resistance. However, the same functions of MT protect against the negative effects of chemotherapeutic treatment. It is especially important in case of heart cells. Analysis of MT expression in tumor cells may be useful in choosing method of treatment. It is difficult to determine whether increased expression of MT is only a inducing factor of the development of the carcinogenesis, its malignances and multidrug resistance, or it is a factor inhibiting the induction and development of cancer.

Chloroplast genomes of Arabidopsis halleri ssp. gemmifera and Arabidopsis lyrata ssp. petraea: Structures and comparative analysis.

PubMed

Asaf, Sajjad; Khan, Abdul Latif; Khan, Muhammad Aaqil; Waqas, Muhammad; Kang, Sang-Mo; Yun, Byung-Wook; Lee, In-Jung

2017-08-08

We investigated the complete chloroplast (cp) genomes of non-model Arabidopsis halleri ssp. gemmifera and Arabidopsis lyrata ssp. petraea using Illumina paired-end sequencing to understand their genetic organization and structure. Detailed bioinformatics analysis revealed genome sizes of both subspecies ranging between 154.4~154.5 kbp, with a large single-copy region (84,197~84,158 bp), a small single-copy region (17,738~17,813 bp) and pair of inverted repeats (IRa/IRb; 26,264~26,259 bp). Both cp genomes encode 130 genes, including 85 protein-coding genes, eight ribosomal RNA genes and 37 transfer RNA genes. Whole cp genome comparison of A. halleri ssp. gemmifera and A. lyrata ssp. petraea, along with ten other Arabidopsis species, showed an overall high degree of sequence similarity, with divergence among some intergenic spacers. The location and distribution of repeat sequences were determined, and sequence divergences of shared genes were calculated among related species. Comparative phylogenetic analysis of the entire genomic data set and 70 shared genes between both cp genomes confirmed the previous phylogeny and generated phylogenetic trees with the same topologies. The sister species of A. halleri ssp. gemmifera is A. umezawana, whereas the closest relative of A. lyrata spp. petraea is A. arenicola.

Thermodynamics of Pb(ii) and Zn(ii) binding to MT-3, a neurologically important metallothionein.

PubMed

Carpenter, M C; Shami Shah, A; DeSilva, S; Gleaton, A; Su, A; Goundie, B; Croteau, M L; Stevenson, M J; Wilcox, D E; Austin, R N

2016-06-01

Isothermal titration calorimetry (ITC) was used to quantify the thermodynamics of Pb(2+) and Zn(2+) binding to metallothionein-3 (MT-3). Pb(2+) binds to zinc-replete Zn7MT-3 displacing each zinc ion with a similar change in free energy (ΔG) and enthalpy (ΔH). EDTA chelation measurements of Zn7MT-3 and Pb7MT-3 reveal that both metal ions are extracted in a tri-phasic process, indicating that they bind to the protein in three populations with different binding thermodynamics. Metal binding is entropically favoured, with an enthalpic penalty that reflects the enthalpic cost of cysteine deprotonation accompanying thiolate ligation of the metal ions. These data indicate that Pb(2+) binding to both apo MT-3 and Zn7MT-3 is thermodynamically favourable, and implicate MT-3 in neuronal lead biochemistry.

Using Arabidopsis to understand centromere function: progress and prospects.

PubMed

Copenhaver, Gregory P

2003-01-01

Arabidopsis thaliana has emerged in recent years as a leading model for understanding the structure and function of higher eukaryotic centromeres. Arabidopsis centromeres, like those of virtually all higher eukaryotes, encompass large DNA domains consisting of a complex combination of unique, dispersed middle repetitive and highly repetitive DNA. For this reason, they have required creative analysis using molecular, genetic, cytological and genomic techniques. This synergy of approaches, reinforced by rapid progress in understanding how proteins interact with the centromere DNA to form a complete functional unit, has made Arabidopsis one the best understood centromere systems. Yet major problems remain to be solved: gaining a complete structural definition of the centromere has been surprisingly difficult, and developing synthetic mini-chromosomes in plants has been even more challenging.

Composition and formation of heterochromatin in Arabidopsis thaliana.

PubMed

Fransz, P; ten Hoopen, R; Tessadori, F

2006-01-01

The term heterochromatin has been applied to both large-scale, microscopically visible chromocentres and small-scale, silent genes located outside chromocentres. This may cause confusion in the interpretation of epigenetic marks for both features. The model plant Arabidopsis thaliana provides an excellent system to investigate composition and function of chromatin states at different levels of organization. In this review we will discuss recent developments in molecular networks underlying gene silencing and the relationship with visible heterochromatin in Arabidopsis.

Genetic variation in metallothionein and metal-regulatory transcription factor 1 in relation to urinary cadmium, copper, and zinc

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, Scott V., E-mail: sadams@fhcrc.org; Barrick, Brian; Christopher, Emily P.

Background: Metallothionein (MT) proteins play critical roles in the physiological handling of both essential (Cu and Zn) and toxic (Cd) metals. MT expression is regulated by metal-regulatory transcription factor 1 (MTF1). Hence, genetic variation in the MT gene family and MTF1 might influence excretion of these metals. Methods: 321 women were recruited in Seattle, WA and Las Cruces, NM and provided demographic information, urine samples for measurement of metal concentrations by mass spectrometry and creatinine, and blood or saliva for extraction of DNA. Forty-one single nucleotide polymorphisms (SNPs) within the MTF1 gene region and the region of chromosome 16 encodingmore » the MT gene family were selected for genotyping in addition to an ancestry informative marker panel. Linear regression was used to estimate the association of SNPs with urinary Cd, Cu, and Zn, adjusted for age, urinary creatinine, smoking history, study site, and ancestry. Results: Minor alleles of rs28366003 and rs10636 near the MT2A gene were associated with lower urinary Cd, Cu, and Zn. Minor alleles of rs8044719 and rs1599823, near MT1A and MT1B, were associated with lower urinary Cd and Zn, respectively. Minor alleles of rs4653329 in MTF1 were associated with lower urinary Cd. Conclusions: These results suggest that genetic variation in the MT gene region and MTF1 influences urinary Cd, Cu, and Zn excretion. - Highlights: • Genetic variation in metallothionein (MT) genes was assessed in two diverse populations. • Single nucleotide polymorphisms (SNPs) in MT genes were associated with mean urinary Cd, Cu and Zn. • Genetic variation may influence biomarkers of exposure, and associations of exposure with health.« less

Genome interrogation for novel salinity tolerant Arabidopsis mutants.

PubMed

van Tol, Niels; Pinas, Johan; Schat, Henk; Hooykaas, Paul J J; van der Zaal, Bert J

2016-12-01

Soil salinity is becoming an increasingly large problem in agriculture. In this study, we have investigated whether a capacity to withstand salinity can be induced in the salinity sensitive plant species Arabidopsis thaliana, and whether it can be maintained in subsequent generations. To this end, we have used zinc finger artificial transcription factor (ZF-ATFs) mediated genome interrogation. Already within a relatively small collection Arabidopsis lines expressing ZF-ATFs, we found 41 lines that were tolerant to 100 mM NaCl. Furthermore, ZF-ATF encoding gene constructs rescued from the most strongly salinity tolerant lines were indeed found to act as dominant and heritable agents for salinity tolerance. Altogether, our data provide evidence that a silent capacity to withstand normally lethal levels of salinity exists in Arabidopsis and can be evoked relatively easily by in trans acting transcription factors like ZF-ATFs. © 2016 John Wiley & Sons Ltd.

Tripeptidyl peptidase II. An oligomeric protease complex from Arabidopsis.

PubMed

Book, Adam J; Yang, Peizhen; Scalf, Mark; Smith, Lloyd M; Vierstra, Richard D

2005-06-01

The breakdown of most nuclear and cytoplasmic proteins involves their partial cleavage by the 26S proteasome followed by further disassembly to free amino acids by the combined action of endo- and exopeptidases. In animals, one important intermediate exopeptidase is tripeptidyl peptidase (TPP)II, which digests peptide products of the 26S proteasome and other endopeptidases into tripeptides. Here, we describe the purification and characterization of TPPII from Arabidopsis (Arabidopsis thaliana). Like its animal counterparts, Arabidopsis TPPII exists as a soluble, approximately 5- to 9-MD complex. Two related species of 153 and 142 kD are present in the purified preparations that are derived from a single TPP2 gene. Sequencing by Edman degradation of the intact polypeptides and mass spectrometry of proteolytic fragments demonstrated that the 142-kD form mainly differs from the 153-kD form by a truncation at the C-terminal end. This serine protease is a member of the subtilisin superfamily and is sensitive to the inhibitors alanine-alanine-phenylalanine-chloromethylketone and butabindide, which are diagnostic for the TPPII subfamily. The Arabidopsis TPP2 gene is widely expressed in many tissue types with related genes evident in other plant genomes. Whereas the 26S proteasome is essential, TPPII appears not as important for plant physiology. An Arabidopsis T-DNA mutant defective in TPP2 expression displays no phenotypic abnormalities and is not hypersensitive to either amino acid analogs or the 26S proteasome inhibitor MG132. As a consequence, plants likely contain other intermediate exopeptidases that assist in amino acid recycling.

Metallothionein-Like Proteins and Energy Reserve Levels after Ni and Pb Exposure in the Pacific White Prawn Penaeus vannamei

PubMed Central

Nunez-Nogueira, Gabriel; Mouneyrac, Catherine; Muntz, Alice; Fernandez-Bringas, Laura

2010-01-01

This study analyzed the changes in metallothionein-like proteins (MTLPs) and Energy Reserves (ERs) in hepatopancreas and abdominal muscle of the white prawn Penaeus vannamei. Realistic metal concentration exposure for 10 days to Ni and Pb in solution revealed that juvenile prawns partially induce MTLP in hepatopancreas after Pb exposure. Ni was distributed equally between soluble and insoluble fractions, while Pb was present only in the insoluble fraction, suggesting different detoxification strategy. No changes in lipids and glycogen concentration were detected under these experimental conditions in both tissues analyzed. MTLP could not be considered as a suitable indicator for lead exposure in hepatopancreas. PMID:20862200

Single-cell RNA sequencing reveals metallothionein heterogeneity during hESC differentiation to definitive endoderm.

PubMed

Lu, Junjie; Baccei, Anna; Lummertz da Rocha, Edroaldo; Guillermier, Christelle; McManus, Sean; Finney, Lydia A; Zhang, Cheng; Steinhauser, Matthew L; Li, Hu; Lerou, Paul H

2018-04-01

Differentiation of human pluripotent stem cells towards definitive endoderm (DE) is the critical first step for generating cells comprising organs such as the gut, liver, pancreas and lung. This in-vitro differentiation process generates a heterogeneous population with a proportion of cells failing to differentiate properly and maintaining expression of pluripotency factors such as Oct4. RNA sequencing of single cells collected at four time points during a 4-day DE differentiation identified high expression of metallothionein genes in the residual Oct4-positive cells that failed to differentiate to DE. Using X-ray fluorescence microscopy and multi-isotope mass spectrometry, we discovered that high intracellular zinc level corresponds with persistent Oct4 expression and failure to differentiate. This study improves our understanding of the cellular heterogeneity during in-vitro directed differentiation and provides a valuable resource to improve DE differentiation efficiency. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Potent hydroxyl radical-scavenging activity of drought-induced type-2 metallothionein in wild watermelon.

PubMed

Akashi, Kinya; Nishimura, Noriyuki; Ishida, Yoshinori; Yokota, Akiho

2004-10-08

Wild watermelon (Citrullus lanatus sp.) has the ability to tolerate severe drought/high light stress conditions despite carrying out normal C3-type photosynthesis. Here, mRNA differential display was employed to isolate drought-responsive genes in the leaves of wild watermelon. One of the isolated genes, CLMT2, shared significant homology with type-2 metallothionein (MT) sequences from other plants. The second-order rate constant for the reaction between a recombinant CLMT2 protein and hydroxyl radicals was estimated to be 1.2 x 10(11) M(-1) s(-1), demonstrating that CLMT2 had an extraordinary high activity for detoxifying hydroxyl radicals. Moreover, hydroxyl radical-catalyzed degradation of watermelon genomic DNA was effectively suppressed by CLMT2 in vitro. This is the first demonstration of a plant MT with antioxidant properties. The results suggest that CLMT2 induction contributes to the survival of wild watermelon under severe drought/high light stress conditions. Copyright 2004 Elsevier Inc.

Metallothionein-like multinuclear clusters of mercury(II) and sulfur in peat

USGS Publications Warehouse

Nagy, K.L.; Manceau, A.; Gasper, J.D.; Ryan, J.N.; Aiken, G.R.

2011-01-01

Strong mercury(II)-sulfur (Hg-SR) bonds in natural organic matter, which influence mercury bioavailability, are difficult to characterize. We report evidence for two new Hg-SR structures using X-ray absorption spectroscopy in peats from the Florida Everglades with added Hg. The first, observed at a mole ratio of organic reduced S to Hg (Sred/Hg) between 220 and 1140, is a Hg4Sx type of cluster with each Hg atom bonded to two S atoms at 2.34 ?? and one S at 2.53 ??, and all Hg atoms 4.12 ?? apart. This model structure matches those of metal-thiolate clusters in metallothioneins, but not those of HgS minerals. The second, with one S atom at 2.34 ?? and about six C atoms at 2.97 to 3.28 ??, occurred at S red/Hg between 0.80 and 4.3 and suggests Hg binding to a thiolated aromatic unit. The multinuclear Hg cluster indicates a strong binding environment to cysteinyl sulfur that might impede methylation. Along with a linear Hg(SR)2 unit with Hg - S bond lengths of 2.34 ?? at Sred/Hg of about 10 to 20, the new structures support a continuum in Hg-SR binding strength in natural organic matter. ?? 2011 American Chemical Society.

Ultra-rapid auxin metabolite profiling for high-throughput mutant screening in Arabidopsis.

PubMed

Pencík, Aleš; Casanova-Sáez, Rubén; Pilarová, Veronika; Žukauskaite, Asta; Pinto, Rui; Micol, José Luis; Ljung, Karin; Novák, Ondrej

2018-04-27

Auxin (indole-3-acetic acid, IAA) plays fundamental roles as a signalling molecule during numerous plant growth and development processes. The formation of local auxin gradients and auxin maxima/minima, which is very important for these processes, is regulated by auxin metabolism (biosynthesis, degradation, and conjugation) as well as transport. When studying auxin metabolism pathways it is crucial to combine data obtained from genetic investigations with the identification and quantification of individual metabolites. Thus, to facilitate efforts to elucidate auxin metabolism and its roles in plants, we have developed a high-throughput method for simultaneously quantifying IAA and its key metabolites in minute samples (<10 mg FW) of Arabidopsis thaliana tissues by in-tip micro solid-phase extraction and fast LC-tandem MS. As a proof of concept, we applied the method to a collection of Arabidopsis mutant lines and identified lines with altered IAA metabolite profiles using multivariate data analysis. Finally, we explored the correlation between IAA metabolite profiles and IAA-related phenotypes. The developed rapid analysis of large numbers of samples (>100 samples d-1) is a valuable tool to screen for novel regulators of auxin metabolism and homeostasis among large collections of genotypes.

Rice DB: an Oryza Information Portal linking annotation, subcellular location, function, expression, regulation, and evolutionary information for rice and Arabidopsis

PubMed Central

Narsai, Reena; Devenish, James; Castleden, Ian; Narsai, Kabir; Xu, Lin; Shou, Huixia; Whelan, James

2013-01-01

Omics research in Oryza sativa (rice) relies on the use of multiple databases to obtain different types of information to define gene function. We present Rice DB, an Oryza information portal that is a functional genomics database, linking gene loci to comprehensive annotations, expression data and the subcellular location of encoded proteins. Rice DB has been designed to integrate the direct comparison of rice with Arabidopsis (Arabidopsis thaliana), based on orthology or ‘expressology’, thus using and combining available information from two pre-eminent plant models. To establish Rice DB, gene identifiers (more than 40 types) and annotations from a variety of sources were compiled, functional information based on large-scale and individual studies was manually collated, hundreds of microarrays were analysed to generate expression annotations, and the occurrences of potential functional regulatory motifs in promoter regions were calculated. A range of computational subcellular localization predictions were also run for all putative proteins encoded in the rice genome, and experimentally confirmed protein localizations have been collated, curated and linked to functional studies in rice. A single search box allows anything from gene identifiers (for rice and/or Arabidopsis), motif sequences, subcellular location, to keyword searches to be entered, with the capability of Boolean searches (such as AND/OR). To demonstrate the utility of Rice DB, several examples are presented including a rice mitochondrial proteome, which draws on a variety of sources for subcellular location data within Rice DB. Comparisons of subcellular location, functional annotations, as well as transcript expression in parallel with Arabidopsis reveals examples of conservation between rice and Arabidopsis, using Rice DB (http://ricedb.plantenergy.uwa.edu.au). PMID:24147765

Transcriptional programming during cell wall maturation in the expanding Arabidopsis stem.

PubMed

Hall, Hardy; Ellis, Brian

2013-01-25

Plant cell walls are complex dynamic structures that play a vital role in coordinating the directional growth of plant tissues. The rapid elongation of the inflorescence stem in the model plant Arabidopsis thaliana is accompanied by radical changes in cell wall structure and chemistry, but analysis of the underlying mechanisms and identification of the genes that are involved has been hampered by difficulties in accurately sampling discrete developmental states along the developing stem. By creating stem growth kinematic profiles for individual expanding Arabidopsis stems we have been able to harvest and pool developmentally-matched tissue samples, and to use these for comparative analysis of global transcript profiles at four distinct phases of stem growth: the period of elongation rate increase, the point of maximum growth rate, the point of stem growth cessation and the fully matured stem. The resulting profiles identify numerous genes whose expression is affected as the stem tissues pass through these defined growth transitions, including both novel loci and genes identified in earlier studies. Of particular note is the preponderance of highly active genes associated with secondary cell wall deposition in the region of stem growth cessation, and of genes associated with defence and stress responses in the fully mature stem. The use of growth kinematic profiling to create tissue samples that are accurately positioned along the expansion growth continuum of Arabidopsis inflorescence stems establishes a new standard for transcript profiling analyses of such tissues. The resulting expression profiles identify a substantial number of genes whose expression is correlated for the first time with rapid cell wall extension and subsequent fortification, and thus provide an important new resource for plant biologists interested in gene discovery related to plant biomass accumulation.

An auxin responsive CLE gene regulates shoot apical meristem development in Arabidopsis

PubMed Central

Guo, Hongyan; Zhang, Wei; Tian, Hainan; Zheng, Kaijie; Dai, Xuemei; Liu, Shanda; Hu, Qingnan; Wang, Xianling; Liu, Bao; Wang, Shucai

2015-01-01

Plant hormone auxin regulates most, if not all aspects of plant growth and development, including lateral root formation, organ pattering, apical dominance, and tropisms. Peptide hormones are peptides with hormone activities. Some of the functions of peptide hormones in regulating plant growth and development are similar to that of auxin, however, the relationship between auxin and peptide hormones remains largely unknown. Here we report the identification of OsCLE48, a rice (Oryza sativa) CLE (CLAVATA3/ENDOSPERM SURROUNDING REGION) gene, as an auxin response gene, and the functional characterization of OsCLE48 in Arabidopsis and rice. OsCLE48 encodes a CLE peptide hormone that is similar to Arabidopsis CLEs. RT-PCR analysis showed that OsCLE48 was induced by exogenously application of IAA (indole-3-acetic acid), a naturally occurred auxin. Expression of integrated OsCLE48p:GUS reporter gene in transgenic Arabidopsis plants was also induced by exogenously IAA treatment. These results indicate that OsCLE48 is an auxin responsive gene. Histochemical staining showed that GUS activity was detected in all the tissue and organs of the OsCLE48p:GUS transgenic Arabidopsis plants. Expression of OsCLE48 under the control of the 35S promoter in Arabidopsis inhibited shoot apical meristem development. Expression of OsCLE48 under the control of the CLV3 native regulatory elements almost completely complemented clv3-2 mutant phenotypes, suggesting that OsCLE48 is functionally similar to CLV3. On the other hand, expression of OsCLE48 under the control of the 35S promoter in Arabidopsis has little, if any effects on root apical meristem development, and transgenic rice plants overexpressing OsCLE48 are morphologically indistinguishable from wild type plants, suggesting that the functions of some CLE peptides may not be fully conserved in Arabidopsis and rice. Taken together, our results showed that OsCLE48 is an auxin responsive peptide hormone gene, and it regulates shoot apical

Arabidopsis thaliana telomeres exhibit euchromatic features

PubMed Central

Vaquero-Sedas, María I.; Gámez-Arjona, Francisco M.; Vega-Palas, Miguel A.

2011-01-01

Telomere function is influenced by chromatin structure and organization, which usually involves epigenetic modifications. We describe here the chromatin structure of Arabidopsis thaliana telomeres. Based on the study of six different epigenetic marks we show that Arabidopsis telomeres exhibit euchromatic features. In contrast, subtelomeric regions and telomeric sequences present at interstitial chromosomal loci are heterochromatic. Histone methyltransferases and the chromatin remodeling protein DDM1 control subtelomeric heterochromatin formation. Whereas histone methyltransferases are required for histone H3K92Me and non-CpG DNA methylation, DDM1 directs CpG methylation but not H3K92Me or non-CpG methylation. These results argue that both kinds of proteins participate in different pathways to reinforce subtelomeric heterochromatin formation. PMID:21071395

Role for apyrases in polar auxin transport in Arabidopsis.

PubMed

Liu, Xing; Wu, Jian; Clark, Greg; Lundy, Stacey; Lim, Minhui; Arnold, David; Chan, Jing; Tang, Wenqiang; Muday, Gloria K; Gardner, Gary; Roux, Stanley J

2012-12-01

Recent evidence indicates that extracellular nucleotides regulate plant growth. Exogenous ATP has been shown to block auxin transport and gravitropic growth in primary roots of Arabidopsis (Arabidopsis thaliana). Cells limit the concentration of extracellular ATP in part through the activity of ectoapyrases (ectonucleoside triphosphate diphosphohydrolases), and two nearly identical Arabidopsis apyrases, APY1 and APY2, appear to share this function. These findings, plus the fact that suppression of APY1 and APY2 blocks growth in Arabidopsis, suggested that the expression of these apyrases could influence auxin transport. This report tests that hypothesis. The polar movement of [(3)H]indole-3-acetic acid in both hypocotyl sections and primary roots of Arabidopsis seedlings was measured. In both tissues, polar auxin transport was significantly reduced in apy2 null mutants when they were induced by estradiol to suppress the expression of APY1 by RNA interference. In the hypocotyl assays, the basal halves of APY-suppressed hypocotyls contained considerably lower free indole-3-acetic acid levels when compared with wild-type plants, and disrupted auxin transport in the APY-suppressed roots was reflected by their significant morphological abnormalities. When a green fluorescent protein fluorescence signal encoded by a DR5:green fluorescent protein construct was measured in primary roots whose apyrase expression was suppressed either genetically or chemically, the roots showed no signal asymmetry following gravistimulation, and both their growth and gravitropic curvature were inhibited. Chemicals that suppress apyrase activity also inhibit gravitropic curvature and, to a lesser extent, growth. Taken together, these results indicate that a critical step connecting apyrase suppression to growth suppression is the inhibition of polar auxin transport.

Analysis of functional redundancies within the Arabidopsis TCP transcription factor family.

PubMed

Danisman, Selahattin; van Dijk, Aalt D J; Bimbo, Andrea; van der Wal, Froukje; Hennig, Lars; de Folter, Stefan; Angenent, Gerco C; Immink, Richard G H

2013-12-01

Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by genetic analysis. In the TCP family, however, identification is impeded by relatively low overall sequence similarity. In a search for functionally redundant TCP pairs that control Arabidopsis leaf development, this work performed an integrative bioinformatics analysis, combining protein sequence similarities, gene expression data, and results of pair-wise protein-protein interaction studies for the 24 members of the Arabidopsis TCP transcription factor family. For this, the work completed any lacking gene expression and protein-protein interaction data experimentally and then performed a comprehensive prediction of potential functional redundant TCP pairs. Subsequently, redundant functions could be confirmed for selected predicted TCP pairs by genetic and molecular analyses. It is demonstrated that the previously uncharacterized class I TCP19 gene plays a role in the control of leaf senescence in a redundant fashion with TCP20. Altogether, this work shows the power of combining classical genetic and molecular approaches with bioinformatics predictions to unravel functional redundancies in the TCP transcription factor family.

Analysis of functional redundancies within the Arabidopsis TCP transcription factor family

PubMed Central

Danisman, Selahattin; de Folter, Stefan; Immink, Richard G. H.

2013-01-01

Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by genetic analysis. In the TCP family, however, identification is impeded by relatively low overall sequence similarity. In a search for functionally redundant TCP pairs that control Arabidopsis leaf development, this work performed an integrative bioinformatics analysis, combining protein sequence similarities, gene expression data, and results of pair-wise protein–protein interaction studies for the 24 members of the Arabidopsis TCP transcription factor family. For this, the work completed any lacking gene expression and protein–protein interaction data experimentally and then performed a comprehensive prediction of potential functional redundant TCP pairs. Subsequently, redundant functions could be confirmed for selected predicted TCP pairs by genetic and molecular analyses. It is demonstrated that the previously uncharacterized class I TCP19 gene plays a role in the control of leaf senescence in a redundant fashion with TCP20. Altogether, this work shows the power of combining classical genetic and molecular approaches with bioinformatics predictions to unravel functional redundancies in the TCP transcription factor family. PMID:24129704

Characterization of grape Gibberellin Insensitive 1 mutant alleles in transgenic Arabidopsis

USDA-ARS?s Scientific Manuscript database

We generated a dozen of different mutations in the grape Gibberellin Insensitive or GAI sequence, transformed them into Arabidopsis under the control of 35S, Arabidopsis or grape GAI promoter, and evaluated the impact of these mutant alleles on plant growth and development. These GAI sequence varian...

Gravity-regulated gene expression in Arabidopsis thaliana

NASA Astrophysics Data System (ADS)

Sederoff, Heike; Brown, Christopher S.; Heber, Steffen; Kajla, Jyoti D.; Kumar, Sandeep; Lomax, Terri L.; Wheeler, Benjamin; Yalamanchili, Roopa

Plant growth and development is regulated by changes in environmental signals. Plants sense environmental changes and respond to them by modifying gene expression programs to ad-just cell growth, differentiation, and metabolism. Functional expression of genes comprises many different processes including transcription, translation, post-transcriptional and post-translational modifications, as well as the degradation of RNA and proteins. Recently, it was discovered that small RNAs (sRNA, 18-24 nucleotides long), which are heritable and systemic, are key elements in regulating gene expression in response to biotic and abiotic changes. Sev-eral different classes of sRNAs have been identified that are part of a non-cell autonomous and phloem-mobile network of regulators affecting transcript stability, translational kinetics, and DNA methylation patterns responsible for heritable transcriptional silencing (epigenetics). Our research has focused on gene expression changes in response to gravistimulation of Arabidopsis roots. Using high-throughput technologies including microarrays and 454 sequencing, we iden-tified rapid changes in transcript abundance of genes as well as differential expression of small RNA in Arabidopsis root apices after minutes of reorientation. Some of the differentially regu-lated transcripts are encoded by genes that are important for the bending response. Functional mutants of those genes respond faster to reorientation than the respective wild type plants, indicating that these proteins are repressors of differential cell elongation. We compared the gravity responsive sRNAs to the changes in transcript abundances of their putative targets and identified several potential miRNA: target pairs. Currently, we are using mutant and transgenic Arabidopsis plants to characterize the function of those miRNAs and their putative targets in gravitropic and phototropic responses in Arabidopsis.

Multi-Element Bioimaging of Arabidopsis thaliana Roots.

PubMed

Persson, Daniel Pergament; Chen, Anle; Aarts, Mark G M; Salt, David E; Schjoerring, Jan K; Husted, Søren

2016-10-01

Better understanding of root function is central for the development of plants with more efficient nutrient uptake and translocation. We here present a method for multielement bioimaging at the cellular level in roots of the genetic model system Arabidopsis (Arabidopsis thaliana). Using conventional protocols for microscopy, we observed that diffusible ions such as potassium and sodium were lost during sample dehydration. Thus, we developed a protocol that preserves ions in their native, cellular environment. Briefly, fresh roots are encapsulated in paraffin, cryo-sectioned, and freeze dried. Samples are finally analyzed by laser ablation-inductively coupled plasma-mass spectrometry, utilizing a specially designed internal standard procedure. The method can be further developed to maintain the native composition of proteins, enzymes, RNA, and DNA, making it attractive in combination with other omics techniques. To demonstrate the potential of the method, we analyzed a mutant of Arabidopsis unable to synthesize the metal chelator nicotianamine. The mutant accumulated substantially more zinc and manganese than the wild type in the tissues surrounding the vascular cylinder. For iron, the images looked completely different, with iron bound mainly in the epidermis of the wild-type plants but confined to the cortical cell walls of the mutant. The method offers the power of inductively coupled plasma-mass spectrometry to be fully employed, thereby providing a basis for detailed studies of ion transport in roots. Being applicable to Arabidopsis, the molecular and genetic approaches available in this system can now be fully exploited in order to gain a better mechanistic understanding of these processes. © 2016 American Society of Plant Biologists. All Rights Reserved.

Metallothionein deficiency aggravates depleted uranium-induced nephrotoxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Yuhui; Huang, Jiawei; Gu, Ying

Depleted uranium (DU) has been widely used in both civilian and military activities, and the kidney is the main target organ of DU during acute high-dose exposures. In this study, the nephrotoxicity caused by DU in metallothionein-1/2-null mice (MT −/−) and corresponding wild-type (MT +/+) mice was investigated to determine any associations with MT. Each MT −/− or MT +/+ mouse was pretreated with a single dose of DU (10 mg/kg, intraperitoneal injection) or an equivalent volume of saline. After 4 days of DU administration, kidney changes were assessed. After DU exposure, serum creatinine and serum urea nitrogen in MTmore » −/− mice significantly increased than in MT +/+ mice, with more severe kidney pathological damage. Moreover, catalase and superoxide dismutase (SOD) decreased, and generation of reactive oxygen species and malondialdehyde increased in MT −/− mice. The apoptosis rate in MT −/− mice significantly increased, with a significant increase in both Bax and caspase 3 and a decrease in Bcl-2. Furthermore, sodium-glucose cotransporter (SGLT) and sodium-phosphate cotransporter (NaPi-II) were significantly reduced after DU exposure, and the change of SGLT was more evident in MT −/− mice. Finally, exogenous MT was used to evaluate the correlation between kidney changes induced by DU and MT doses in MT −/− mice. The results showed that, the pathological damage and cell apoptosis decreased, and SOD and SGLT levels increased with increasing dose of MT. In conclusion, MT deficiency aggravated DU-induced nephrotoxicity, and the molecular mechanisms appeared to be related to the increased oxidative stress and apoptosis, and decreased SGLT expression. - Highlights: • MT −/− and MT +/+ mice were used to evaluate nephrotoxicity of DU. • Renal damage was more evident in the MT −/− mice after exposure to DU. • Exogenous MT also protects against DU-induced nephrotoxicity. • MT deficiency induced more ROS and apoptosis after

Chromosome landmarks as tools to study the genome of Arabidopsis thaliana.

PubMed

Siroky, J

2008-01-01

The model plant Arabidopsis thaliana has long been used for genetic, cellular and molecular studies. Whereas this plant was used as a model of genetics in the 1940's, the first cytogenetic observation of A. thaliana chromosomes was published in the beginning of the 20th century. Although Arabidopsis was not originally considered to be a good plant model for cytogenetics due to smallness of its genome, the number of published chromosome studies has expanded enormously in recent years. The advent of fluorescence in situ hybridization techniques on meiotic chromosomes together with indirect immuno-fluorescence localization of key chromosomal and nuclear proteins and wide accessibility of Arabidopsis mutants have resulted in a synergistic boost in Arabidopsis cytogenetics. In comparison to other plant species, the small genome with under-represented DNA repeats together with a small number of chromosomes makes this model plant easy to comprehend for a cytologist. 2008 S. Karger AG, Basel

Genome-wide analysis of ABA-responsive elements ABRE and CE3 reveals divergent patterns in Arabidopsis and rice

PubMed Central

Gómez-Porras, Judith L; Riaño-Pachón, Diego Mauricio; Dreyer, Ingo; Mayer, Jorge E; Mueller-Roeber, Bernd

2007-01-01

Background In plants, complex regulatory mechanisms are at the core of physiological and developmental processes. The phytohormone abscisic acid (ABA) is involved in the regulation of various such processes, including stomatal closure, seed and bud dormancy, and physiological responses to cold, drought and salinity stress. The underlying tissue or plant-wide control circuits often include combinatorial gene regulatory mechanisms and networks that we are only beginning to unravel with the help of new molecular tools. The increasing availability of genomic sequences and gene expression data enables us to dissect ABA regulatory mechanisms at the individual gene expression level. In this paper we used an in-silico-based approach directed towards genome-wide prediction and identification of specific features of ABA-responsive elements. In particular we analysed the genome-wide occurrence and positional arrangements of two well-described ABA-responsive cis-regulatory elements (CREs), ABRE and CE3, in thale cress (Arabidopsis thaliana) and rice (Oryza sativa). Results Our results show that Arabidopsis and rice use the ABA-responsive elements ABRE and CE3 distinctively. Earlier reports for various monocots have identified CE3 as a coupling element (CE) associated with ABRE. Surprisingly, we found that while ABRE is equally abundant in both species, CE3 is practically absent in Arabidopsis. ABRE-ABRE pairs are common in both genomes, suggesting that these can form functional ABA-responsive complexes (ABRCs) in Arabidopsis and rice. Furthermore, we detected distinct combinations, orientation patterns and DNA strand preferences of ABRE and CE3 motifs in rice gene promoters. Conclusion Our computational analyses revealed distinct recruitment patterns of ABA-responsive CREs in upstream sequences of Arabidopsis and rice. The apparent absence of CE3s in Arabidopsis suggests that another CE pairs with ABRE to establish a functional ABRC capable of interacting with transcription

Genome-wide analysis of ABA-responsive elements ABRE and CE3 reveals divergent patterns in Arabidopsis and rice.

PubMed

Gómez-Porras, Judith L; Riaño-Pachón, Diego Mauricio; Dreyer, Ingo; Mayer, Jorge E; Mueller-Roeber, Bernd

2007-08-01

In plants, complex regulatory mechanisms are at the core of physiological and developmental processes. The phytohormone abscisic acid (ABA) is involved in the regulation of various such processes, including stomatal closure, seed and bud dormancy, and physiological responses to cold, drought and salinity stress. The underlying tissue or plant-wide control circuits often include combinatorial gene regulatory mechanisms and networks that we are only beginning to unravel with the help of new molecular tools. The increasing availability of genomic sequences and gene expression data enables us to dissect ABA regulatory mechanisms at the individual gene expression level. In this paper we used an in-silico-based approach directed towards genome-wide prediction and identification of specific features of ABA-responsive elements. In particular we analysed the genome-wide occurrence and positional arrangements of two well-described ABA-responsive cis-regulatory elements (CREs), ABRE and CE3, in thale cress (Arabidopsis thaliana) and rice (Oryza sativa). Our results show that Arabidopsis and rice use the ABA-responsive elements ABRE and CE3 distinctively. Earlier reports for various monocots have identified CE3 as a coupling element (CE) associated with ABRE. Surprisingly, we found that while ABRE is equally abundant in both species, CE3 is practically absent in Arabidopsis. ABRE-ABRE pairs are common in both genomes, suggesting that these can form functional ABA-responsive complexes (ABRCs) in Arabidopsis and rice. Furthermore, we detected distinct combinations, orientation patterns and DNA strand preferences of ABRE and CE3 motifs in rice gene promoters. Our computational analyses revealed distinct recruitment patterns of ABA-responsive CREs in upstream sequences of Arabidopsis and rice. The apparent absence of CE3s in Arabidopsis suggests that another CE pairs with ABRE to establish a functional ABRC capable of interacting with transcription factors. Further studies will be

Cadmium modulates adipocyte functions in metallothionein-null mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawakami, Takashige; Nishiyama, Kaori; Kadota, Yoshito

2013-11-01

Our previous study has demonstrated that exposure to cadmium (Cd), a toxic heavy metal, causes a reduction of adipocyte size and the modulation of adipokine expression. To further investigate the significance of the Cd action, we studied the effect of Cd on the white adipose tissue (WAT) of metallothionein null (MT{sup −/−}) mice, which cannot form atoxic Cd–MT complexes and are used for evaluating Cd as free ions, and wild type (MT{sup +/+}) mice. Cd administration more significantly reduced the adipocyte size of MT{sup −/−} mice than that of MT{sup +/+} mice. Cd exposure also induced macrophage recruitment to WATmore » with an increase in the expression level of Ccl2 (MCP-1) in the MT{sup −/−} mice. The in vitro exposure of Cd to adipocytes induce triglyceride release into culture medium, decrease in the expression levels of genes involved in fatty acid synthesis and lipid hydrolysis at 24 h, and at 48 h increase in phosphorylation of the lipid-droplet-associated protein perilipin, which facilitates the degradation of stored lipids in adipocytes. Therefore, the reduction in adipocyte size by Cd may arise from an imbalance between lipid synthesis and lipolysis. In addition, the expression levels of leptin, adiponectin and resistin decreased in adipocytes. Taken together, exposure to Cd may induce unusually small adipocytes and modulate the expression of adipokines differently from the case of physiologically small adipocytes, and may accelerate the risk of developing insulin resistance and type 2 diabetes. - Highlights: • Cd causes a marked reduction in adipocyte size in MT-null mice. • Cd enhances macrophage migration into adipose tissue and disrupt adipokine secretion. • MT gene alleviates Cd-induced adipocyte dysfunctions. • Cd enhances the degradation of stored lipids in adipocytes, mediated by perilipin. • Cd induces unusually small adipocytes and the abnormal expression of adipokines.« less

Validation of Pooled Whole-Genome Re-Sequencing in Arabidopsis lyrata.

PubMed

Fracassetti, Marco; Griffin, Philippa C; Willi, Yvonne

2015-01-01

Sequencing pooled DNA of multiple individuals from a population instead of sequencing individuals separately has become popular due to its cost-effectiveness and simple wet-lab protocol, although some criticism of this approach remains. Here we validated a protocol for pooled whole-genome re-sequencing (Pool-seq) of Arabidopsis lyrata libraries prepared with low amounts of DNA (1.6 ng per individual). The validation was based on comparing single nucleotide polymorphism (SNP) frequencies obtained by pooling with those obtained by individual-based Genotyping By Sequencing (GBS). Furthermore, we investigated the effect of sample number, sequencing depth per individual and variant caller on population SNP frequency estimates. For Pool-seq data, we compared frequency estimates from two SNP callers, VarScan and Snape; the former employs a frequentist SNP calling approach while the latter uses a Bayesian approach. Results revealed concordance correlation coefficients well above 0.8, confirming that Pool-seq is a valid method for acquiring population-level SNP frequency data. Higher accuracy was achieved by pooling more samples (25 compared to 14) and working with higher sequencing depth (4.1× per individual compared to 1.4× per individual), which increased the concordance correlation coefficient to 0.955. The Bayesian-based SNP caller produced somewhat higher concordance correlation coefficients, particularly at low sequencing depth. We recommend pooling at least 25 individuals combined with sequencing at a depth of 100× to produce satisfactory frequency estimates for common SNPs (minor allele frequency above 0.05).

Molecular association of Arabidopsis RTH with its homolog RTE1 in regulating ethylene signaling.

PubMed

Zheng, Fangfang; Cui, Xiankui; Rivarola, Maximo; Gao, Ting; Chang, Caren; Dong, Chun-Hai

2017-05-17

The plant hormone ethylene affects many biological processes during plant growth and development. Ethylene is perceived by ethylene receptors at the endoplasmic reticulum (ER) membrane. The ETR1 ethylene receptor is positively regulated by the transmembrane protein RTE1, which localizes to the ER and Golgi apparatus. The RTE1 gene family is conserved in animals, plants, and lower eukaryotes. In Arabidopsis, RTE1-HOMOLOG (RTH) is the only homolog of the Arabidopsis RTE1 gene family. The regulatory function of the Arabidopsis RTH in ethylene signaling and plant growth is largely unknown. The present study shows Arabidopsis RTH gene expression patterns, protein co-localization with the ER and Golgi apparatus, and the altered ethylene response phenotype when RTH is knocked out or overexpressed in Arabidopsis. Compared with rte1 mutants, rth mutants exhibit less sensitivity to exogenous ethylene, while RTH overexpression confers ethylene hypersensitivity. Genetic analyses indicate that Arabidopsis RTH might not directly regulate the ethylene receptors. RTH can physically interact with RTE1, and evidence supports that RTH might act via RTE1 in regulating ethylene responses and signaling. The present study advances our understanding of the regulatory function of the Arabidopsis RTE1 gene family members in ethylene signaling. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

AIM: a comprehensive Arabidopsis interactome module database and related interologs in plants.

PubMed

Wang, Yi; Thilmony, Roger; Zhao, Yunjun; Chen, Guoping; Gu, Yong Q

2014-01-01

Systems biology analysis of protein modules is important for understanding the functional relationships between proteins in the interactome. Here, we present a comprehensive database named AIM for Arabidopsis (Arabidopsis thaliana) interactome modules. The database contains almost 250,000 modules that were generated using multiple analysis methods and integration of microarray expression data. All the modules in AIM are well annotated using multiple gene function knowledge databases. AIM provides a user-friendly interface for different types of searches and offers a powerful graphical viewer for displaying module networks linked to the enrichment annotation terms. Both interactive Venn diagram and power graph viewer are integrated into the database for easy comparison of modules. In addition, predicted interologs from other plant species (homologous proteins from different species that share a conserved interaction module) are available for each Arabidopsis module. AIM is a powerful systems biology platform for obtaining valuable insights into the function of proteins in Arabidopsis and other plants using the modules of the Arabidopsis interactome. Database URL:http://probes.pw.usda.gov/AIM Published by Oxford University Press 2014. This work is written by US Government employees and is in the public domain in the US.

Comparison of the response of serum ceruloplasmin and cholesterol, and of tissue ascorbic acid, metallothionein, and nonprotein sulfhydryl in rats to the dietary level of cystine and cysteine.

PubMed

Yang, B S; Yamazaki, M; Wan, Q; Kato, N

1996-12-01

The effects were compared of the addition of graded levels of L-cystine and of L-cysteine (0.3, 3, or 5%) to a 10% casein diet on several metabolic parameters in rats. The growth-promoting effect of cystine was equivalent to that of cysteine. Supplementation of these two amino acids elevated serum cholesterol, liver ascorbic acid, liver nonprotein sulfhydryl (SH) and kidney metallothionein, and reduced the activity of serum ceruloplasmin. The responses of serum cholesterol, liver nonprotein SH, and serum ceruloplasmin to cystine were greater than of those to cysteine. When the basal diet was supplemented with 0.3% of these amino acids, the elevation of liver ascorbic acid by cystine supplementation was less than that by cysteine supplementation. However, when supplemented with 5% of these amino acids, the elevation of liver ascorbic acid by cystine was greater than that by cysteine. There was no difference in the influence of cystine and cysteine on kidney metallothionein. This study demonstrates that dietary cystine and cysteine had the same influence on growth, but had a differential influence on such metabolic parameters as liver nonprotein SH, serum ceruloplasmin, serum cholesterol, and tissue ascorbic acid.

The demise of chloroplast DNA in Arabidopsis.

PubMed

Rowan, Beth A; Oldenburg, Delene J; Bendich, Arnold J

2004-09-01

Although it might be expected that chloroplast DNA (cpDNA) would be stably maintained in mature leaves, we report the surprising observation that cpDNA levels decline during plastid development in Arabidopsis thaliana (Col.) until most of the leaves contain little or no DNA long before the onset of senescence. We measured the cpDNA content in developing cotyledons, rosette leaves, and cauline leaves. The amount of cpDNA per chloroplast decreases as the chloroplasts develop, reaching undetectable levels in mature leaves. In young cauline leaves, most individual molecules of cpDNA are found in complex, branched forms. In expanded cauline leaves, cpDNA is present in smaller branched forms only at the base of the leaf and is virtually absent in the distal part of the leaf. We conclude that photosynthetic activity may persist long after the demise of the cpDNA. Copyright 2004 Springer-Verlag

AIM: A comprehensive Arabidopsis Interactome Module database and related interologs in plants

USDA-ARS?s Scientific Manuscript database

Systems biology analysis of protein modules is important for understanding the functional relationships between proteins in the interactome. Here, we present a comprehensive database named AIM for Arabidopsis (Arabidopsis thaliana) interactome modules. The database contains almost 250,000 modules th...

Increase methylmercury accumulation in Arabidopsis thaliana expressing bacterial broad-spectrum mercury transporter MerE

PubMed Central

2013-01-01

The bacterial merE gene derived from the Tn21 mer operon encodes a broad-spectrum mercury transporter that governs the transport of methylmercury and mercuric ions across bacterial cytoplasmic membranes, and this gene is a potential molecular tool for improving the efficiency of methylmercury phytoremediation. A transgenic Arabidopsis engineered to express MerE was constructed and the impact of expression of MerE on methylmercury accumulation was evaluated. The subcellular localization of transiently expressed GFP-tagged MerE was examined in Arabidopsis suspension-cultured cells. The GFP-MerE was found to localize to the plasma membrane and cytosol. The transgenic Arabidopsis expressing MerE accumulated significantly more methymercury and mercuric ions into plants than the wild-type Arabidopsis did. The transgenic plants expressing MerE was significantly more resistant to mercuric ions, but only showed more resistant to methylmercury compared with the wild type Arabidopsis. These results demonstrated that expression of the bacterial mercury transporter MerE promoted the transport and accumulation of methylmercury in transgenic Arabidopsis, which may be a useful method for improving plants to facilitate the phytoremediation of methylmercury pollution. PMID:24004544

A nondestructive method to estimate the chlorophyll content of Arabidopsis seedlings

DOE PAGES

Liang, Ying; Urano, Daisuke; Liao, Kang-Ling; ...

2017-04-14

Chlorophyll content decreases in plants under stress conditions, therefore it is used commonly as an indicator of plant health. Arabidopsis thaliana offers a convenient and fast way to test physiological phenotypes of mutations and treatments. But, chlorophyll measurements with conventional solvent extraction are not applicable to Arabidopsis leaves due to their small size, especially when grown on culture dishes. We provide a nondestructive method for chlorophyll measurement whereby the red, green and blue (RGB) values of a color leaf image is used to estimate the chlorophyll content from Arabidopsis leaves. The method accommodates different profiles of digital cameras by incorporatingmore » the ColorChecker chart to make the digital negative profiles, to adjust the white balance, and to calibrate the exposure rate differences caused by the environment so that this method is applicable in any environment. We chose an exponential function model to estimate chlorophyll content from the RGB values, and fitted the model parameters with physical measurements of chlorophyll contents. As further proof of utility, this method was used to estimate chlorophyll content of G protein mutants grown on different sugar to nitrogen ratios. Our method is a simple, fast, inexpensive, and nondestructive estimation of chlorophyll content of Arabidopsis seedlings. This method lead to the discovery that G proteins are important in sensing the C/N balance to control chlorophyll content in Arabidopsis.« less

The Functions of Metamorphic Metallothioneins in Zinc and Copper Metabolism.

PubMed

Krężel, Artur; Maret, Wolfgang

2017-06-09

Recent discoveries in zinc biology provide a new platform for discussing the primary physiological functions of mammalian metallothioneins (MTs) and their exquisite zinc-dependent regulation. It is now understood that the control of cellular zinc homeostasis includes buffering of Zn 2+ ions at picomolar concentrations, extensive subcellular re-distribution of Zn 2+ , the loading of exocytotic vesicles with zinc species, and the control of Zn 2+ ion signalling. In parallel, characteristic features of human MTs became known: their graded affinities for Zn 2+ and the redox activity of their thiolate coordination environments. Unlike the single species that structural models of mammalian MTs describe with a set of seven divalent or eight to twelve monovalent metal ions, MTs are metamorphic. In vivo, they exist as many species differing in redox state and load with different metal ions. The functions of mammalian MTs should no longer be considered elusive or enigmatic because it is now evident that the reactivity and coordination dynamics of MTs with Zn 2+ and Cu⁺ match the biological requirements for controlling-binding and delivering-these cellular metal ions, thus completing a 60-year search for their functions. MT represents a unique biological principle for buffering the most competitive essential metal ions Zn 2+ and Cu⁺. How this knowledge translates to the function of other families of MTs awaits further insights into the specifics of how their properties relate to zinc and copper metabolism in other organisms.

Rice DB: an Oryza Information Portal linking annotation, subcellular location, function, expression, regulation, and evolutionary information for rice and Arabidopsis.

PubMed

Narsai, Reena; Devenish, James; Castleden, Ian; Narsai, Kabir; Xu, Lin; Shou, Huixia; Whelan, James

2013-12-01

Omics research in Oryza sativa (rice) relies on the use of multiple databases to obtain different types of information to define gene function. We present Rice DB, an Oryza information portal that is a functional genomics database, linking gene loci to comprehensive annotations, expression data and the subcellular location of encoded proteins. Rice DB has been designed to integrate the direct comparison of rice with Arabidopsis (Arabidopsis thaliana), based on orthology or 'expressology', thus using and combining available information from two pre-eminent plant models. To establish Rice DB, gene identifiers (more than 40 types) and annotations from a variety of sources were compiled, functional information based on large-scale and individual studies was manually collated, hundreds of microarrays were analysed to generate expression annotations, and the occurrences of potential functional regulatory motifs in promoter regions were calculated. A range of computational subcellular localization predictions were also run for all putative proteins encoded in the rice genome, and experimentally confirmed protein localizations have been collated, curated and linked to functional studies in rice. A single search box allows anything from gene identifiers (for rice and/or Arabidopsis), motif sequences, subcellular location, to keyword searches to be entered, with the capability of Boolean searches (such as AND/OR). To demonstrate the utility of Rice DB, several examples are presented including a rice mitochondrial proteome, which draws on a variety of sources for subcellular location data within Rice DB. Comparisons of subcellular location, functional annotations, as well as transcript expression in parallel with Arabidopsis reveals examples of conservation between rice and Arabidopsis, using Rice DB (http://ricedb.plantenergy.uwa.edu.au). © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Tripeptidyl Peptidase II. An Oligomeric Protease Complex from Arabidopsis1

PubMed Central

Book, Adam J.; Yang, Peizhen; Scalf, Mark; Smith, Lloyd M.; Vierstra, Richard D.

2005-01-01

The breakdown of most nuclear and cytoplasmic proteins involves their partial cleavage by the 26S proteasome followed by further disassembly to free amino acids by the combined action of endo- and exopeptidases. In animals, one important intermediate exopeptidase is tripeptidyl peptidase (TPP)II, which digests peptide products of the 26S proteasome and other endopeptidases into tripeptides. Here, we describe the purification and characterization of TPPII from Arabidopsis (Arabidopsis thaliana). Like its animal counterparts, Arabidopsis TPPII exists as a soluble, approximately 5- to 9-MD complex. Two related species of 153 and 142 kD are present in the purified preparations that are derived from a single TPP2 gene. Sequencing by Edman degradation of the intact polypeptides and mass spectrometry of proteolytic fragments demonstrated that the 142-kD form mainly differs from the 153-kD form by a truncation at the C-terminal end. This serine protease is a member of the subtilisin superfamily and is sensitive to the inhibitors alanine-alanine-phenylalanine-chloromethylketone and butabindide, which are diagnostic for the TPPII subfamily. The Arabidopsis TPP2 gene is widely expressed in many tissue types with related genes evident in other plant genomes. Whereas the 26S proteasome is essential, TPPII appears not as important for plant physiology. An Arabidopsis T-DNA mutant defective in TPP2 expression displays no phenotypic abnormalities and is not hypersensitive to either amino acid analogs or the 26S proteasome inhibitor MG132. As a consequence, plants likely contain other intermediate exopeptidases that assist in amino acid recycling. PMID:15908606

Crambescin C1 Exerts a Cytoprotective Effect on HepG2 Cells through Metallothionein Induction

PubMed Central

Roel, María; Rubiolo, Juan A.; Ternon, Eva; Thomas, Olivier P.; Vieytes, Mercedes R.; Botana, Luis M.

2015-01-01

The Mediterranean marine sponge Crambe crambe is the source of two families of guanidine alkaloids known as crambescins and crambescidins. Some of the biological effects of crambescidins have been previously reported while crambescins have undergone little study. Taking this into account, we performed comparative transcriptome analysis to examine the effect of crambescin-C1 (CC1) on human tumor hepatocarcinoma cells HepG2 followed by validation experiments to confirm its predicted biological activities. We report herein that, while crambescin-A1 has a minor effect on these cells, CC1 protects them against oxidative injury by means of metallothionein induction even at low concentrations. Additionally, at high doses, CC1 arrests the HepG2 cell cycle in G0/G1 and thus inhibits tumor cell proliferation. The findings presented here provide the first detailed approach regarding the different effects of crambescins on tumor cells and provide a basis for future studies on other possible cellular mechanisms related to these bioactivities. PMID:26225985

Overexpression of the Arabidopsis 10-kilodalton acyl-coenzyme A-binding protein ACBP6 enhances freezing tolerance.

PubMed

Chen, Qin-Fang; Xiao, Shi; Chye, Mee-Len

2008-09-01

Small 10-kD acyl-coenzyme A-binding proteins (ACBPs) are highly conserved proteins that are prevalent in eukaryotes. In Arabidopsis (Arabidopsis thaliana), other than the 10-kD ACBP homolog (designated Arabidopsis ACBP6), there are five larger forms of ACBPs ranging from 37.5 to 73.1 kD. In this study, the cytosolic subcellular localization of Arabidopsis ACBP6 was confirmed by analyses of transgenic Arabidopsis expressing autofluorescence-tagged ACBP6 and western-blot analysis of subcellular fractions using ACBP6-specific antibodies. The expression of Arabidopsis ACBP6 was noticeably induced at 48 h after 4 degrees C treatment by northern-blot analysis and western-blot analysis. Furthermore, an acbp6 T-DNA insertional mutant that lacked ACBP6 mRNA and protein displayed increased sensitivity to freezing temperature (-8 degrees C), while ACBP6-overexpressing transgenic Arabidopsis plants were conferred enhanced freezing tolerance. Northern-blot analysis indicated that ACBP6-associated freezing tolerance was not dependent on the induction of cold-regulated COLD-RESPONSIVE gene expression. Instead, ACBP6 overexpressors showed increased expression of mRNA encoding phospholipase Ddelta. Lipid profiling analyses of rosettes from cold-acclimated, freezing-treated (-8 degrees C) transgenic Arabidopsis plants overexpressing ACBP6 showed a decline in phosphatidylcholine (-36% and -46%) and an elevation of phosphatidic acid (73% and 67%) in comparison with wild-type plants. From our comparison, the gain in freezing tolerance in ACBP6 overexpressors that was accompanied by decreases in phosphatidylcholine and an accumulation of phosphatidic acid is consistent with previous findings on phospholipase Ddelta-overexpressing transgenic Arabidopsis. In vitro filter-binding assays indicating that histidine-tagged ACBP6 binds phosphatidylcholine, but not phosphatidic acid or lysophosphatidylcholine, further imply a role for ACBP6 in phospholipid metabolism in Arabidopsis, including

Building an efficient curation workflow for the Arabidopsis literature corpus

PubMed Central

Li, Donghui; Berardini, Tanya Z.; Muller, Robert J.; Huala, Eva

2012-01-01

TAIR (The Arabidopsis Information Resource) is the model organism database (MOD) for Arabidopsis thaliana, a model plant with a literature corpus of about 39 000 articles in PubMed, with over 4300 new articles added in 2011. We have developed a literature curation workflow incorporating both automated and manual elements to cope with this flood of new research articles. The current workflow can be divided into two phases: article selection and curation. Structured controlled vocabularies, such as the Gene Ontology and Plant Ontology are used to capture free text information in the literature as succinct ontology-based annotations suitable for the application of computational analysis methods. We also describe our curation platform and the use of text mining tools in our workflow. Database URL: www.arabidopsis.org PMID:23221298

The next generation of training for Arabidopsis researchers: bioinformatics and quantitative biology

USDA-ARS?s Scientific Manuscript database

It has been more than 50 years since Arabidopsis (Arabidopsis thaliana) was first introduced as a model organism to understand basic processes in plant biology. A well-organized scientific community has used this small reference plant species to make numerous fundamental plant biology discoveries (P...

Phenotypic characterization of an Arabidopsis T-DNA insertion line SALK_063500.

PubMed

Sng, Natasha J; Paul, Anna-Lisa; Ferl, Robert J

2018-06-01

In this article we report the identification of a homozygous lethal T-DNA (transfer DNA) line within the coding region of the At1G05290 gene in the genome of Arabidopsis thaliana (Arabidopsis) line, SALK_063500. The T-DNA insertion is found within exon one of the AT1G05290 gene, however a homozygous T-DNA allele is unattainable. In the heterozygous T-DNA allele the expression levels of AT1G05290 were compared to wild type Arabidopsis (Col-0, Columbia). Further analyses revealed an aberrant silique phenotype found in the heterozygous SALK_063500 plants that is attributed to the reduced rate of pollen tube germination. These data are original and have not been published elsewhere.

Classification and phylogenetic analyses of the Arabidopsis and tomato G-type lectin receptor kinases.

PubMed

Teixeira, Marcella A; Rajewski, Alex; He, Jiangman; Castaneda, Olenka G; Litt, Amy; Kaloshian, Isgouhi

2018-04-06

Pathogen perception by plants is mediated by plasma membrane-localized immune receptors that have varied extracellular domains. Lectin receptor kinases (LecRKs) are among these receptors and are subdivided into 3 classes, C-type LecRKs (C-LecRKs), L-type LecRKs (L-LecRKs) and G-type LecRKs (G-LecRKs). While C-LecRKs are represented by one or two members in all plant species investigated and have unknown functions, L-LecRKs have been characterized in a few plant species and have been shown to play roles in plant defense against pathogens. Whereas Arabidopsis G-LecRKs have been characterized, this family of LecRKs has not been studied in tomato. This investigation updates the current characterization of Arabidopsis G-LecRKs and characterizes the tomato G-LecRKs, using LecRKs from the monocot rice and the basal eudicot columbine to establish a basis for comparisons between the two core eudicots. Additionally, revisiting parameters established for Arabidopsis nomenclature for LecRKs is suggested for both Arabidopsis and tomato. Moreover, using phylogenetic analysis, we show the relationship among and between members of G-LecRKs from all three eudicot plant species. Furthermore, investigating presence of motifs in G-LecRKs we identified conserved motifs among members of G-LecRKs in tomato and Arabidopsis, with five present in at least 30 of the 38 Arabidopsis members and in at least 45 of the 73 tomato members. This work characterized tomato G-LecRKs and added members to the currently characterized Arabidopsis G-LecRKs. Additionally, protein sequence analysis showed an expansion of this family in tomato as compared to Arabidopsis, and the existence of conserved common motifs in the two plant species as well as conserved species-specific motifs.

Phosphorylation of plastoglobular proteins in Arabidopsis thaliana

PubMed Central

Lohscheider, Jens N.; Friso, Giulia; van Wijk, Klaas J.

2016-01-01

Plastoglobules (PGs) are plastid lipid–protein particles with a small specialized proteome and metabolome. Among the 30 core PG proteins are six proteins of the ancient ABC1 atypical kinase (ABC1K) family and their locations in an Arabidopsis mRNA-based co-expression network suggested central regulatory roles. To identify candidate ABC1K targets and a possible ABC1K hierarchical phosphorylation network within the chloroplast PG proteome, we searched Arabidopsis phosphoproteomics data from publicly available sources. Evaluation of underlying spectra and/or associated information was challenging for a variety of reasons, but supported pSer sites and a few pThr sites in nine PG proteins, including five FIBRILLINS. PG phosphorylation motifs are discussed in the context of possible responsible kinases. The challenges of collection and evaluation of published Arabidopsis phosphorylation data are discussed, illustrating the importance of deposition of all mass spectrometry data in well-organized repositories such as PRIDE and ProteomeXchange. This study provides a starting point for experimental testing of phosho-sites in PG proteins and also suggests that phosphoproteomics studies specifically designed toward the PG proteome and its ABC1K are needed to understand phosphorylation networks in these specialized particles. PMID:26962209

Seed-to-seed-to-seed growth and development of Arabidopsis in microgravity.

PubMed

Link, Bruce M; Busse, James S; Stankovic, Bratislav

2014-10-01

Arabidopsis thaliana was grown from seed to seed wholly in microgravity on the International Space Station. Arabidopsis plants were germinated, grown, and maintained inside a growth chamber prior to returning to Earth. Some of these seeds were used in a subsequent experiment to successfully produce a second (back-to-back) generation of microgravity-grown Arabidopsis. In general, plant growth and development in microgravity proceeded similarly to those of the ground controls, which were grown in an identical chamber. Morphologically, the most striking feature of space-grown Arabidopsis was that the secondary inflorescence branches and siliques formed nearly perpendicular angles to the inflorescence stems. The branches grew out perpendicularly to the main inflorescence stem, indicating that gravity was the key determinant of branch and silique angle and that light had either no role or a secondary role in Arabidopsis branch and silique orientation. Seed protein bodies were 55% smaller in space seed than in controls, but protein assays showed only a 9% reduction in seed protein content. Germination rates for space-produced seed were 92%, indicating that the seeds developed in microgravity were healthy and viable. Gravity is not necessary for seed-to-seed growth of plants, though it plays a direct role in plant form and may influence seed reserves.

Functional analysis of the theobroma cacao NPR1 gene in arabidopsis

PubMed Central

2010-01-01

Background The Arabidopsis thaliana NPR1 gene encodes a transcription coactivator (NPR1) that plays a major role in the mechanisms regulating plant defense response. After pathogen infection and in response to salicylic acid (SA) accumulation, NPR1 translocates from the cytoplasm into the nucleus where it interacts with other transcription factors resulting in increased expression of over 2000 plant defense genes contributing to a pathogen resistance response. Results A putative Theobroma cacao NPR1 cDNA was isolated by RT-PCR using degenerate primers based on homologous sequences from Brassica, Arabidopsis and Carica papaya. The cDNA was used to isolate a genomic clone from Theobroma cacao containing a putative TcNPR1 gene. DNA sequencing revealed the presence of a 4.5 kb coding region containing three introns and encoding a polypeptide of 591 amino acids. The predicted TcNPR1 protein shares 55% identity and 78% similarity to Arabidopsis NPR1, and contains each of the highly conserved functional domains indicative of this class of transcription factors (BTB/POZ and ankyrin repeat protein-protein interaction domains and a nuclear localization sequence (NLS)). To functionally define the TcNPR1 gene, we transferred TcNPR1 into an Arabidopsis npr1 mutant that is highly susceptible to infection by the plant pathogen Pseudomonas syringae pv. tomato DC3000. Driven by the constitutive CaMV35S promoter, the cacao TcNPR1 gene partially complemented the npr1 mutation in transgenic Arabidopsis plants, resulting in 100 fold less bacterial growth in a leaf infection assay. Upon induction with SA, TcNPR1 was shown to translocate into the nucleus of leaf and root cells in a manner identical to Arabidopsis NPR1. Cacao NPR1 was also capable of participating in SA-JA signaling crosstalk, as evidenced by the suppression of JA responsive gene expression in TcNPR1 overexpressing transgenic plants. Conclusion Our data indicate that the TcNPR1 is a functional ortholog of Arabidopsis NPR1

Functional analysis of the Theobroma cacao NPR1 gene in Arabidopsis.

PubMed

Shi, Zi; Maximova, Siela N; Liu, Yi; Verica, Joseph; Guiltinan, Mark J

2010-11-15

The Arabidopsis thaliana NPR1 gene encodes a transcription coactivator (NPR1) that plays a major role in the mechanisms regulating plant defense response. After pathogen infection and in response to salicylic acid (SA) accumulation, NPR1 translocates from the cytoplasm into the nucleus where it interacts with other transcription factors resulting in increased expression of over 2000 plant defense genes contributing to a pathogen resistance response. A putative Theobroma cacao NPR1 cDNA was isolated by RT-PCR using degenerate primers based on homologous sequences from Brassica, Arabidopsis and Carica papaya. The cDNA was used to isolate a genomic clone from Theobroma cacao containing a putative TcNPR1 gene. DNA sequencing revealed the presence of a 4.5 kb coding region containing three introns and encoding a polypeptide of 591 amino acids. The predicted TcNPR1 protein shares 55% identity and 78% similarity to Arabidopsis NPR1, and contains each of the highly conserved functional domains indicative of this class of transcription factors (BTB/POZ and ankyrin repeat protein-protein interaction domains and a nuclear localization sequence (NLS)). To functionally define the TcNPR1 gene, we transferred TcNPR1 into an Arabidopsis npr1 mutant that is highly susceptible to infection by the plant pathogen Pseudomonas syringae pv. tomato DC3000. Driven by the constitutive CaMV35S promoter, the cacao TcNPR1 gene partially complemented the npr1 mutation in transgenic Arabidopsis plants, resulting in 100 fold less bacterial growth in a leaf infection assay. Upon induction with SA, TcNPR1 was shown to translocate into the nucleus of leaf and root cells in a manner identical to Arabidopsis NPR1. Cacao NPR1 was also capable of participating in SA-JA signaling crosstalk, as evidenced by the suppression of JA responsive gene expression in TcNPR1 overexpressing transgenic plants. Our data indicate that the TcNPR1 is a functional ortholog of Arabidopsis NPR1, and is likely to play a

Grafting in Arabidopsis.

PubMed

Bainbridge, Katherine; Bennett, Tom; Crisp, Peter; Leyser, Ottoline; Turnbull, Colin

2014-01-01

Grafting provides a simple way to generate chimeric plants with regions of different genotypes and thus to assess the cell autonomy of gene action. The technique of grafting has been widely used in other species, but in Arabidopsis, its small size makes the process rather more demanding. However, there are now several well-established grafting procedures available, which we described here, and their use has already contributed greatly to understanding of such processes as shoot branching control, flowering, disease resistance, and systemic silencing.

Metabolic profiling of Arabidopsis thaliana epidermal cells

PubMed Central

Ebert, Berit; Zöller, Daniela; Erban, Alexander; Fehrle, Ines; Hartmann, Jürgen; Niehl, Annette; Kopka, Joachim; Fisahn, Joachim

2010-01-01

Metabolic phenotyping at cellular resolution may be considered one of the challenges in current plant physiology. A method is described which enables the cell type-specific metabolic analysis of epidermal cell types in Arabidopsis thaliana pavement, basal, and trichome cells. To achieve the required high spatial resolution, single cell sampling using microcapillaries was combined with routine gas chromatography-time of flight-mass spectrometry (GC-TOF-MS) based metabolite profiling. The identification and relative quantification of 117 mostly primary metabolites has been demonstrated. The majority, namely 90 compounds, were accessible without analytical background correction. Analyses were performed using cell type-specific pools of 200 microsampled individual cells. Moreover, among these identified metabolites, 38 exhibited differential pool sizes in trichomes, basal or pavement cells. The application of an independent component analysis confirmed the cell type-specific metabolic phenotypes. Significant pool size changes between individual cells were detectable within several classes of metabolites, namely amino acids, fatty acids and alcohols, alkanes, lipids, N-compounds, organic acids and polyhydroxy acids, polyols, sugars, sugar conjugates and phenylpropanoids. It is demonstrated here that the combination of microsampling and GC-MS based metabolite profiling provides a method to investigate the cellular metabolism of fully differentiated plant cell types in vivo. PMID:20150518

Determination of dietary cadmium-induced metallothioneins in rabbit kidneys and cadmium in metallothioneins by anion-exchange high-performance liquid chromatography coupled with graphite furnace atomic absorption spectrometry.

PubMed

Peng, S; Shan, X Q; Zheng, Y; Jin, L Z; Xu, W B

1991-12-06

A rapid method is described for the determination of dietary cadmium-induced metallothioneins (MTs) in rabbit kidneys by anion-exchange high-performance liquid chromatography. Rabbit kidney MT-I and MT-II were eluted at ca. 15.0 and 18.8 min, respectively, from a DEAE-5PW anion-exchange column with a Tris-HCl buffer (0.01-0.25 M, pH 8.6) and detected by ultraviolet absorbance at 254 nm. A standard calibration curve was constructed using purified standard MT isoforms, which demonstrated an excellent linear correlation between UV absorbance peak heights and the amounts of MT isoforms. Feeding a dose of cadmium for some days resulted in an increase in MT concentrations in rabbit kidneys, but not in the livers. The cadmium concentrations in MT-I and MT-II elutions were determined by graphite furnace atomic absorption spectrometry. MT-I and MT-II showed some differences associated with the oral intake of cadmium. Dietary cadmium also caused zinc to accumulate in kidneys to some extent. The effects of dietary oleic acid on the synthesis of MTs were also studied. Based on the method of standard additions, the recovery of MTs exceeded 93% and replicated injection of samples yielded a relative standard deviation of 2.4% at an MT level of 280 micrograms/g.

Short-term exposure of Arabidopsis cell culures to hyper-G: Short-term changes in transcription regulation expression

NASA Astrophysics Data System (ADS)

Babbick, Maren; Hampp, Rudiger

2005-08-01

Callus cultures of Arabidopsis thaliana (cv. Columbia) were used to screen for early changes in gene expression in response to altered gravitational fields. In a recent microarray study we found hyper- g dependent changes in gene expression which indicated the involvement of WRKY genes [Martzivanou M. and Hampp R., Physiol. Plant., 118, 221-231,2003]. WRKY genes code for a family of plant-specific regulators of gene expression. In this study we report on the exposure of Arabidopsis callus cultures to 8g for up to 30 min. Quantitative analysis by real time RT-PCR of the amount of transcripts of WRKYs 3, 6, 22, 46, 65 and 70 showed individual changes in expression. As far as their function is known, these WRKY proteins are mainly involved in stress responses. As most alterations in transcript amount occurred within 10 min of treatment, such genes can be used for the investigation of microgravity-related effects on gene expression under sounding rocket conditions (TEXUS, MAXUS).

Root gravitropism in maize and Arabidopsis

NASA Technical Reports Server (NTRS)

Evans, Michael L.

1993-01-01

Research during the period 1 March 1992 to 30 November 1993 focused on improvements in a video digitizer system designed to automate the recording of surface extension in plants responding to gravistimulation. The improvements included modification of software to allow detailed analysis of localized extension patterns in roots of Arabidopsis. We used the system to analyze the role of the postmitotic isodiametric growth zone (a region between the meristem and the elongation zone) in the response of maize roots to auxin, calcium, touch and gravity. We also used the system to analyze short-term auxin and gravitropic responses in mutants of Arabidopsis with reduced auxin sensitivity. In a related project, we studied the relationship between growth rate and surface electrical currents in roots by examining the effects of gravity and thigmostimulation on surface potentials in maize roots.

Metallothionein as potential biomarker of cadmium exposure in Persian sturgeon (Acipenser persicus).

PubMed

Shariati, Fatemeh; Esaili Sari, Abbas; Mashinchian, Ali; Pourkazemi, Mohammad

2011-10-01

Metallothionein (MT) concentration in gills, liver, and kidney tissues of Persian sturgeon (Acipenser persicus) were determined following exposure to sublethal levels of waterborne cadmium (Cd) (50, 400, and 1,000 μg l(-1)) after 1, 2, 4, and 14 days. The increases of MT from background levels were 4.6-, 3-, and 2.8-fold for kidney, liver, and gills, respectively. The results showed that MT level change in the kidney is time and concentration dependent. Also, cortisol measurement revealed elevation at the day 1 of exposure and followed by MT increase in the liver. Cd concentrations in the cytosol of experimental tissues were measured, and the results indicated that Cd levels in the cytosol of liver, kidney, and gills increased 240.71-, 32.05-, and 40.16-fold, respectively, 14 days after exposure to 1,000 μg l(-1) Cd. The accumulation of Cd in cytosol of tissues is in the order of liver > gills > kidney. Pearson correlation coefficients showed that the MT content in kidney is correlated with Cd concentration, the value of which is more than in liver and gills. Thus, kidney can be considered as a tissue indicator in A. persicus for waterborne Cd contamination.

Metallothionein: a Potential Link in the Regulation of Zinc in Nutritional Immunity.

PubMed

Rahman, Mohammad Tariqur; Karim, Muhammad Manjurul

2018-03-01

Nutritional immunity describes mechanisms for withholding essential transition metals as well as directing the toxicity of these metals against infectious agents. Zinc is one of these transition elements that are essential for both humans and microbial pathogens. At the same time, Zn can be toxic both for man and microbes if its concentration is higher than the tolerance limit. Therefore a "delicate" balance of Zn must be maintained to keep the immune cells surveilling while making the level of Zn either to starve or to intoxicate the pathogens. On the other hand, the invading pathogens will exploit the host Zn pool for its survival and replication. Apparently, different sets of protein in human and bacteria are involved to maintain their Zn need. Metallothionein (MT)-a group of low molecular weight proteins, is well known for its Zn-binding ability and is expected to play an important role in that Zn balance at the time of active infection. However, the differences in structural, functional, and molecular control of biosynthesis between human and bacterial MT might play an important role to determine the proper use of Zn and the winning side. The current review explains the possible involvement of human and bacterial MT at the time of infection to control and exploit Zn for their need.

The influence of biological and environmental factors on metallothionein concentration in the blood.

PubMed

Kowalska, Katarzyna; Bizoń, Anna; Zalewska, Marta; Milnerowicz, Halina

2015-01-01

The concentration of metallothionein (MT), a low-molecular-weight protein, is regulated by many factors, primarily metals (zinc, cadmium, copper), cytokines, glucocorticoides and free radicals. These factors are determined by such aspects of human biology as gender, pregnancy and age, as well as by environmental factors including the use of oral contraceptives and cigarette smoking, all which may affect MT levels in the body. The aim of this study was to investigate the influence of these biological and environmental factors on MT concentrations in erythrocyte lysate and in plasma. MT concentrations were determined by a two-step direct enzyme-linked immunosorbent assay. Evaluation of exposure to cigarette smoking was performed by checking cotinine levels in the plasma of subjects. The studies showed higher MT concentrations in both the erythrocyte lysate and plasma of women when compared to men. Furthermore, pregnancy causes an increase of MT concentration in plasma, while oral contraceptives cause an elevated concentration of MT in erythrocyte lysate. Age impacts plasma MT concentrations in men, whereas it does not affect concentrations of MT in erythrocyte lysate. Copyright © 2014 Elsevier GmbH. All rights reserved.

Dual-mode enhancement of metallothionein protein with cell transduction and retention peptide fusion.

PubMed

Lim, Kwang Suk; Lim, Myoung-Hwa; Won, Young-Wook; Kim, Jang Kyoung; Kang, Young Cheol; Park, Eun Jeong; Chae, Ji-Won; Kim, So-Mi; Ryu, Seong-Eon; Pak, Youngmi Kim; Kim, Yong-Hee

2013-10-28

Protein transduction domains (PTDs), also known as cell-penetrating peptides (CPPs), have been developed as effective systems for delivering bio-active cargos such as proteins, genes and particles. Further improvements on cell-specific targeting, intracellular organelle targeting and intracellular retention are still necessary to enhance the therapeutic effect of PTD fusion proteins. In order to enhance the cell transduction and retention of anti-oxidative metallothionein protein (MT), MT was recombinantly fused with transcriptional activator (Tat) with or without a short peptide (sMTS) derived from mitochondria malate dehydrogenase (mMDH). Cellular uptake and retention time of fusion protein were significantly increased in the H9c2 cell by sMTS. The Tat-sMTS-MT (TMM) fusion protein protected H9c2 cells more effectively against hypoxia, hyperglycemia and combination compared with Tat-MT (TM) by reducing intracellular ROS level. It maintained the normal blood glucose level over an extended period of time in a streptozotocin-induced diabetic mouse model. PTD-sMTS-MT fusion protein has a potential to be used as a therapeutic protein for the treatment or prevention of diabetes and diabetic complications. © 2013.

Analysis of the effects of overexpression of metallothionein-I in transgenic mice on the reproductive toxicology of cadmium.

PubMed Central

Dalton, T; Fu, K; Enders, G C; Palmiter, R D; Andrews, G K

1996-01-01

Exposure to low levels of cadmium reduces fertility. In male mice spermatogenesis is highly sensitive to cadmium, whereas in females the peri-implantation period of pregnancy is sensitive. To examine the potential roles of the cadmium-binding protein, metallothionein (MT), in the reproductive toxicology of cadmium, we examined a transgenic mouse strain that overexpresses metallothionein-I (MT-I). These mice had dramatically increased steady-state levels of MT-I mRNA and MT in the testes and in the female reproductive tract during the peri-implantation period of pregnancy, and this overexpression occurred in a cell-specific and temporally regulated manner similar to that of the endogenous MT-I gene. Transgenic and control males were injected with cadmium, and the histology of the testes was examined. An injection of 7.5 mumol Cd/kg had no effect on histology of the testes in either transgenic or control mice. In contrast, an injection of 10 mumol Cd/kg caused rapid changes in the histology of the testes and resulted in pronounced testicular necrosis in both control and transgenic mice. Female transgenic and control mice were mated and then injected with cadmium (30-45 mumol Cd/kg) on the day of blastocyst implantation (day 4). In both of these groups, injection of cadmium reduced pregnancy rate, and no dramatic protection was afforded by maternal and/or embryonic overexpression of MT. Thus, overexpression of MT-I does not significantly protect against either of these cadmium-induced effects on fertility. Images Figure 1. A Figure 1. B Figure 2. A Figure 2. B Figure 2. C Figure 3. Figure 4. A Figure 4. A Figure 4. B Figure 4. B Figure 4. B Figure 4. B Figure 4. D4 Figure 4. D4 Figure 4. D6 Figure 4. D6 Figure 4. D8 Figure 5. A Figure 5. B Figure 5. C Figure 5. D Figure 5. E Figure 6. A Figure 6. B Figure 6. C Figure 6. D Figure 6. E Figure 6. F PMID:8834864

Arabidopsis cpSRP54 regulates carotenoid accumulation in Arabidopsis and Brassica napus

PubMed Central

Gruber, Margaret Y.; Hannoufa, Abdelali

2012-01-01

An Arabidopsis thaliana mutant, cbd (carotenoid biosynthesis deficient), was recovered from a mutant population based on its yellow cotyledons, yellow-first true leaves, and stunted growth. Seven-day-old seedlings and mature seeds of this mutant had lower chlorophyll and total carotenoids than the wild type (WT). Genetic and molecular characterization revealed that cbd was a recessive mutant caused by a T-DNA insertion in the gene cpSRP54 encoding the 54kDa subunit of the chloroplast signal recognition particle. Transcript levels of most of the main carotenoid biosynthetic genes in cbd were unchanged relative to WT, but expression increased in carotenoid and abscisic acid catabolic genes. The chloroplasts of cbd also had developmental defects that contributed to decreased carotenoid and chlorophyll contents. Transcription of AtGLK1 (Golden 2-like 1), AtGLK2, and GUN4 appeared to be disrupted in the cbd mutant suggesting that the plastid-to-nucleus retrograde signal may be affected, regulating the changes in chloroplast functional and developmental states and carotenoid content flux. Transformation of A. thaliana and Brassica napus with a gDNA encoding the Arabidopsis cpSRP54 showed the utility of this gene in enhancing levels of seed carotenoids without affecting growth or seed yield. PMID:22791829

GOLDEN2-LIKE transcription factors coordinate the tolerance to Cucumber mosaic virus in Arabidopsis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Xue-Ying; Li, Peng-Xu; Zou, Li-Juan

Arabidopsis thaliana GOLDEN2-LIKE (GLKs) transcription factors play important roles in regulation of photosynthesis-associated nuclear genes, as well as participate in chloroplast development. However, the involvement of GLKs in plants resistance to virus remains largely unknown. Here, the relationship between GLKs and Cucumber mosaic virus (CMV) stress response was investigated. Our results showed that the Arabidopsis glk1glk2 double-mutant was more susceptible to CMV infection and suffered more serious damages (such as higher oxidative damages, more compromised in PSII photochemistry and more reactive oxygen species accumulation) when compared with the wild-type plants. Interestingly, there was little difference between single mutant (glk1 ormore » glk2) and wild-type plants in response to CMV infection, suggesting GLK1 and GLK2 might function redundant in virus resistance in Arabidopsis. Furthermore, the induction of antioxidant system and defense-associated genes expression in the double mutant were inhibited when compared with single mutant or wild-type plants after CMV infection. Further evidences showed that salicylic acid (SA) and jasmonic acid (JA) might be involved in GLKs-mediated virus resistance, as SA or JA level and synthesis-related genes transcription were impaired in glk1glk2 mutant. Taken together, our results indicated that GLKs played a positively role in virus resistance in Arabidopsis. - Highlights: • GLKs play a positive role in CMV resistance in Arabidopsis. • Defective of GLKs suffered more ROS accumulation. • Arabidopsis lacking GLKs have damaged photosynthesis. • Arabidopsis lacking GLKs show low SA and JA accumulation.« less

Synthesis of hydroxylated sterols in transgenic Arabidopsis plants alters growth and steroid metabolism.

PubMed

Beste, Lisa; Nahar, Nurun; Dalman, Kerstin; Fujioka, Shozo; Jonsson, Lisbeth; Dutta, Paresh C; Sitbon, Folke

2011-09-01

To explore mechanisms in plant sterol homeostasis, we have here increased the turnover of sterols in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum) plants by overexpressing four mouse cDNA encoding cholesterol hydroxylases (CHs), hydroxylating cholesterol at the C-7, C-24, C-25, or C-27 positions. Compared to the wild type, the four types of Arabidopsis transformant showed varying degrees of phenotypic alteration, the strongest one being in CH25 lines, which were dark-green dwarfs resembling brassinosteroid-related mutants. Gas chromatography-mass spectrometry analysis of extracts from wild-type Arabidopsis plants revealed trace levels of α and β forms of 7-hydroxycholesterol, 7-hydroxycampesterol, and 7-hydroxysitosterol. The expected hydroxycholesterol metabolites in CH7-, CH24-, and CH25 transformants were identified and quantified using gas chromatography-mass spectrometry. Additional hydroxysterol forms were also observed, particularly in CH25 plants. In CH24 and CH25 lines, but not in CH7 ones, the presence of hydroxysterols was correlated with a considerable alteration of the sterol profile and an increased sterol methyltransferase activity in microsomes. Moreover, CH25 lines contained clearly reduced levels of brassinosteroids, and displayed an enhanced drought tolerance. Equivalent transformations of potato plants with the CH25 construct increased hydroxysterol levels, but without the concomitant alteration of growth and sterol profiles observed in Arabidopsis. The results suggest that an increased hydroxylation of cholesterol and/or other sterols in Arabidopsis triggers compensatory processes, acting to maintain sterols at adequate levels.

P-proteins in Arabidopsis are heteromeric structures involved in rapid sieve tube sealing.

PubMed

Jekat, Stephan B; Ernst, Antonia M; von Bohl, Andreas; Zielonka, Sascia; Twyman, Richard M; Noll, Gundula A; Prüfer, Dirk

2013-01-01

Structural phloem proteins (P-proteins) are characteristic components of the sieve elements in all dicotyledonous and many monocotyledonous angiosperms. Tobacco P-proteins were recently confirmed to be encoded by the widespread sieve element occlusion (SEO) gene family, and tobacco SEO proteins were shown to be directly involved in sieve tube sealing thus preventing the loss of photosynthate. Analysis of the two Arabidopsis SEO proteins (AtSEOa and AtSEOb) indicated that the corresponding P-protein subunits do not act in a redundant manner. However, there are still pending questions regarding the interaction properties and specific functions of AtSEOa and AtSEOb as well as the general function of structural P-proteins in Arabidopsis. In this study, we characterized the Arabidopsis P-proteins in more detail. We used in planta bimolecular fluorescence complementation assays to confirm the predicted heteromeric interactions between AtSEOa and AtSEOb. Arabidopsis mutants depleted for one or both AtSEO proteins lacked the typical P-protein structures normally found in sieve elements, underlining the identity of AtSEO proteins as P-proteins and furthermore providing the means to determine the role of Arabidopsis P-proteins in sieve tube sealing. We therefore developed an assay based on phloem exudation. Mutants with reduced AtSEO expression levels lost twice as much photosynthate following injury as comparable wild-type plants, confirming that Arabidopsis P-proteins are indeed involved in sieve tube sealing.

P-proteins in Arabidopsis are heteromeric structures involved in rapid sieve tube sealing

PubMed Central

Jekat, Stephan B.; Ernst, Antonia M.; von Bohl, Andreas; Zielonka, Sascia; Twyman, Richard M.; Noll, Gundula A.; Prüfer, Dirk

2013-01-01

Structural phloem proteins (P-proteins) are characteristic components of the sieve elements in all dicotyledonous and many monocotyledonous angiosperms. Tobacco P-proteins were recently confirmed to be encoded by the widespread sieve element occlusion (SEO) gene family, and tobacco SEO proteins were shown to be directly involved in sieve tube sealing thus preventing the loss of photosynthate. Analysis of the two Arabidopsis SEO proteins (AtSEOa and AtSEOb) indicated that the corresponding P-protein subunits do not act in a redundant manner. However, there are still pending questions regarding the interaction properties and specific functions of AtSEOa and AtSEOb as well as the general function of structural P-proteins in Arabidopsis. In this study, we characterized the Arabidopsis P-proteins in more detail. We used in planta bimolecular fluorescence complementation assays to confirm the predicted heteromeric interactions between AtSEOa and AtSEOb. Arabidopsis mutants depleted for one or both AtSEO proteins lacked the typical P-protein structures normally found in sieve elements, underlining the identity of AtSEO proteins as P-proteins and furthermore providing the means to determine the role of Arabidopsis P-proteins in sieve tube sealing. We therefore developed an assay based on phloem exudation. Mutants with reduced AtSEO expression levels lost twice as much photosynthate following injury as comparable wild-type plants, confirming that Arabidopsis P-proteins are indeed involved in sieve tube sealing. PMID:23840197

Comprehensive analysis of CLE polypeptide signaling gene expression and overexpression activity in Arabidopsis

USDA-ARS?s Scientific Manuscript database

Technical Abstract: Intercellular signaling is essential for the coordination of growth and development in higher plants. Although hundreds of putative receptors have been identified in Arabidopsis (Arabidopsis thaliana), only a few families of extracellular signaling molecules have been discovered...

A role for seed storage proteins in Arabidopsis seed longevity

PubMed Central

Nguyen, Thu-Phuong; Cueff, Gwendal; Hegedus, Dwayne D; Rajjou, Loïc; Bentsink, Leónie

2015-01-01

Proteomics approaches have been a useful tool for determining the biological roles and functions of individual proteins and identifying the molecular mechanisms that govern seed germination, vigour and viability in response to ageing. In this work the dry seed proteome of four Arabidopsis thaliana genotypes, that carry introgression fragments at the position of seed longevity quantitative trait loci and as a result display different levels of seed longevity, was investigated. Seeds at two physiological states, after-ripened seeds that had the full germination ability and aged (stored) seeds of which the germination ability was severely reduced, were compared. Aged dry seed proteomes were markedly different from the after-ripened and reflected the seed longevity level of the four genotypes, despite the fact that dry seeds are metabolically quiescent. Results confirmed the role of antioxidant systems, notably vitamin E, and indicated that protection and maintenance of the translation machinery and energy pathways are essential for seed longevity. Moreover, a new role for seed storage proteins (SSPs) was identified in dry seeds during ageing. Cruciferins (CRUs) are the most abundant SSPs in Arabidopsis and seeds of a triple mutant for three CRU isoforms (crua crub cruc) were more sensitive to artificial ageing and their seed proteins were highly oxidized compared with wild-type seeds. These results confirm that oxidation is involved in seed deterioration and that SSPs buffer the seed from oxidative stress, thus protecting important proteins required for seed germination and seedling formation. PMID:26184996

Strigolactones suppress adventitious rooting in Arabidopsis and pea.

PubMed

Rasmussen, Amanda; Mason, Michael Glenn; De Cuyper, Carolien; Brewer, Philip B; Herold, Silvia; Agusti, Javier; Geelen, Danny; Greb, Thomas; Goormachtig, Sofie; Beeckman, Tom; Beveridge, Christine Anne

2012-04-01

Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation.

Seed-to-Seed-to-Seed Growth and Development of Arabidopsis in Microgravity

PubMed Central

Link, Bruce M.; Busse, James S.

2014-01-01

Abstract Arabidopsis thaliana was grown from seed to seed wholly in microgravity on the International Space Station. Arabidopsis plants were germinated, grown, and maintained inside a growth chamber prior to returning to Earth. Some of these seeds were used in a subsequent experiment to successfully produce a second (back-to-back) generation of microgravity-grown Arabidopsis. In general, plant growth and development in microgravity proceeded similarly to those of the ground controls, which were grown in an identical chamber. Morphologically, the most striking feature of space-grown Arabidopsis was that the secondary inflorescence branches and siliques formed nearly perpendicular angles to the inflorescence stems. The branches grew out perpendicularly to the main inflorescence stem, indicating that gravity was the key determinant of branch and silique angle and that light had either no role or a secondary role in Arabidopsis branch and silique orientation. Seed protein bodies were 55% smaller in space seed than in controls, but protein assays showed only a 9% reduction in seed protein content. Germination rates for space-produced seed were 92%, indicating that the seeds developed in microgravity were healthy and viable. Gravity is not necessary for seed-to-seed growth of plants, though it plays a direct role in plant form and may influence seed reserves. Key Words: Arabidopsis—Branch—Inflorescence—Microgravity—Morphology—Seed—Space. Astrobiology 14, 866–875. PMID:25317938

Wheat TaSP gene improves salt tolerance in transgenic Arabidopsis thaliana.

PubMed

Ma, Xiaoli; Cui, Weina; Liang, Wenji; Huang, Zhanjing

2015-12-01

A novel salt-induced gene with unknown functions was cloned through analysis of gene expression profile of a salt-tolerant wheat mutant RH8706-49 under salt stress. The gene was named Triticum aestivum salt-related protein (TaSP) and deposited in GenBank (Accession No. KF307326). Quantitative polymerase chain reaction (qPCR) results showed that TaSP expression was induced under salt, abscisic acid (ABA), and polyethylene glycol (PEG) stresses. Subcellular localization revealed that TaSP was mainly localized in cell membrane. Overexpression of TaSP in Arabidopsis could improve salt tolerance of 35S::TaSP transgenic Arabidopsis. 35S::TaSP transgenic Arabidopsis lines after salt stress presented better physiological indexes than the control group. In the non-invasive micro-test (NMT), an evident Na(+) excretion was observed at the root tip of salt-stressed 35S::TaSP transgenic Arabidopsis. TaSP promoter was cloned, and its beta-glucuronidase (GUS) activities before and after ABA, salt, cold, heat, and salicylic acid (SA) stresses were determined. Full-length TaSP promoter contained ABA and salt response elements. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Auxin polar transport in arabidopsis under simulated microgravity conditions - relevance to growth and development

NASA Astrophysics Data System (ADS)

Miyamoto, K.; Oka, M.; Yamamoto, R.; Masuda, Y.; Hoson, T.; Kamisaka, S.; Ueda, J.

1999-01-01

Activity of auxin polar transport in inflorescence axes of Arabidopsis thaliana grown under simulated microgravity conditions was studied in relation to the growth and development. Seeds were germinated and allowed to grow on an agar medium in test tubes on a horizontal clinostat. Horizontal clinostat rotation substantially reduced the growth of inflorescence axes and the productivity of seeds of Arabidopsis thaliana (ecotypes Landsberg erecta and Columbia), although it little affected seed germination, development of rosette leaves and flowering. The activity of auxin polar transport in inflorescence axes decreased when Arabidopsis plants were grown on a horizontal clinostat from germination stage, being ca. 60% of 1 g control. On the other hand, the auxin polar transport in inflorescence axes of Arabidopsis grown in 1 g conditions was not affected when the segments were exposed to various gravistimuli, including 3-dimensional clinorotation, during transport experiments. Pin-formed mutant of Arabidopsis, having a unique structure of the inflorescence axis with no flower and extremely low levels of the activity of auxin polar transport in inflorescence axes and endogenous auxin, did not continue its vegetative growth under clinostat rotation. These facts suggest that the development of the system of auxin polar transport in Arabidopsis is affected by microgravity, resulting in the inhibition of growth and development, especially during reproductive growth.

The fifth international conference on Arabidopsis research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hangarter, R.; Scholl, R.; Davis, K.

This volume contains abstracts of oral and poster presentations made in conjunction with the Fifth International Conference on Arabidopsis Research held August 19--22, 1993 at the Ohio State University, Columbus, Ohio.

Demographic History of European Populations of Arabidopsis thaliana

PubMed Central

François, Olivier; Blum, Michael G. B.; Jakobsson, Mattias; Rosenberg, Noah A.

2008-01-01

The model plant species Arabidopsis thaliana is successful at colonizing land that has recently undergone human-mediated disturbance. To investigate the prehistoric spread of A. thaliana, we applied approximate Bayesian computation and explicit spatial modeling to 76 European accessions sequenced at 876 nuclear loci. We find evidence that a major migration wave occurred from east to west, affecting most of the sampled individuals. The longitudinal gradient appears to result from the plant having spread in Europe from the east ∼10,000 years ago, with a rate of westward spread of ∼0.9 km/year. This wave-of-advance model is consistent with a natural colonization from an eastern glacial refugium that overwhelmed ancient western lineages. However, the speed and time frame of the model also suggest that the migration of A. thaliana into Europe may have accompanied the spread of agriculture during the Neolithic transition. PMID:18483550

Bursts of retrotransposition reproduced in Arabidopsis.

PubMed

Tsukahara, Sayuri; Kobayashi, Akie; Kawabe, Akira; Mathieu, Olivier; Miura, Asuka; Kakutani, Tetsuji

2009-09-17

Retrotransposons, which proliferate by reverse transcription of RNA intermediates, comprise a major portion of plant genomes. Plants often change the genome size and organization during evolution by rapid proliferation and deletion of long terminal repeat (LTR) retrotransposons. Precise transposon sequences throughout the Arabidopsis thaliana genome and the trans-acting mutations affecting epigenetic states make it an ideal model organism with which to study transposon dynamics. Here we report the mobilization of various families of endogenous A. thaliana LTR retrotransposons identified through genetic and genomic approaches with high-resolution genomic tiling arrays and mutants in the chromatin-remodelling gene DDM1 (DECREASE IN DNA METHYLATION 1). Using multiple lines of self-pollinated ddm1 mutant, we detected an increase in copy number, and verified this for various retrotransposons in a gypsy family (ATGP3) and copia families (ATCOPIA13, ATCOPIA21, ATCOPIA93), and also for a DNA transposon of a Mutator family, VANDAL21. A burst of retrotransposition occurred stochastically and independently for each element, suggesting an additional autocatalytic process. Furthermore, comparison of the identified LTR retrotransposons in related Arabidopsis species revealed that a lineage-specific burst of retrotransposition of these elements did indeed occur in natural Arabidopsis populations. The recent burst of retrotransposition in natural population is targeted to centromeric repeats, which is presumably less harmful than insertion into genes. The ddm1-induced retrotransposon proliferations and genome rearrangements mimic the transposon-mediated genome dynamics during evolution and provide experimental systems with which to investigate the controlling molecular factors directly.

Metallothionein as a Scavenger of Free Radicals - New Cardioprotective Therapeutic Agent or Initiator of Tumor Chemoresistance?

PubMed

Heger, Zbynek; Rodrigo, Miguel Angel Merlos; Krizkova, Sona; Ruttkay-Nedecky, Branislav; Zalewska, Marta; Del Pozo, Elena Maria Planells; Pelfrene, Aurelie; Pourrut, Bertrand; Stiborova, Marie; Eckschlager, Tomas; Emri, Gabriella; Kizek, Rene; Adam, Vojtech

2016-01-01

Cardiotoxicity is a serious complication of anticancer therapy by anthracycline antibiotics. Except for intercalation into DNA/RNA structure, inhibition of DNA-topoisomerase and histone eviction from chromatin, the main mechanism of their action is iron-mediated formation of various forms of free radicals, which leads to irreversible damage to cancer cells. The most serious adverse effect of anthracyclines is, thus, cardiomyopathy leading to congestive heart failure, which is caused by the same mechanisms. Here, we briefly summarize the basic types of free radicals formed by anthracyclines and the main processes how to scavenge them. From these, the main attention is paid to metallothioneins. These low-molecular cysteine-rich proteins are introduced and their functions and properties are reviewed. Further, their role in detoxification of metals and drugs is discussed. Based on these beneficial roles, their use as a new therapeutic agent against oxidative stress and for cardioprotection is critically evaluated with respect to their ability to increase chemoresistance against some types of commonly used cytostatics.

Analysis of protein interactions within the cytokinin-signaling pathway of Arabidopsis thaliana.

PubMed

Dortay, Hakan; Mehnert, Nijuscha; Bürkle, Lukas; Schmülling, Thomas; Heyl, Alexander

2006-10-01

The signal of the plant hormone cytokinin is perceived by membrane-located sensor histidine kinases and transduced by other members of the plant two-component system. In Arabidopsis thaliana, 28 two-component system proteins (phosphotransmitters and response regulators) act downstream of three receptors, transmitting the signal from the membrane to the nucleus and modulating the cellular response. Although the principal signaling mechanism has been elucidated, redundancy in the system has made it difficult to understand which of the many components interact to control the downstream biological processes. Here, we present a large-scale interaction study comprising most members of the Arabidopsis cytokinin signaling pathway. Using the yeast two-hybrid system, we detected 42 new interactions, of which more than 90% were confirmed by in vitro coaffinity purification. There are distinct patterns of interaction between protein families, but only a few interactions between proteins of the same family. An interaction map of this signaling pathway shows the Arabidopsis histidine phosphotransfer proteins as hubs, which interact with members from all other protein families, mostly in a redundant fashion. Domain-mapping experiments revealed the interaction domains of the proteins of this pathway. Analyses of Arabidopsis histidine phosphotransfer protein 5 mutant proteins showed that the presence of the canonical phospho-accepting histidine residue is not required for the interactions. Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling. This study contributes to our understanding of the protein interactions of the cytokinin-signaling system and provides a framework for further functional studies in planta.

Seed Dormancy in Arabidopsis Is Controlled by Alternative Polyadenylation of DOG1.

PubMed

Cyrek, Malgorzata; Fedak, Halina; Ciesielski, Arkadiusz; Guo, Yanwu; Sliwa, Aleksandra; Brzezniak, Lien; Krzyczmonik, Katarzyna; Pietras, Zbigniew; Kaczanowski, Szymon; Liu, Fuquan; Swiezewski, Szymon

2016-02-01

DOG1 (Delay of Germination 1) is a key regulator of seed dormancy in Arabidopsis (Arabidopsis thaliana) and other plants. Interestingly, the C terminus of DOG1 is either absent or not conserved in many plant species. Here, we show that in Arabidopsis, DOG1 transcript is subject to alternative polyadenylation. In line with this, mutants in RNA 3' processing complex display weakened seed dormancy in parallel with defects in DOG1 proximal polyadenylation site selection, suggesting that the short DOG1 transcript is functional. This is corroborated by the finding that the proximally polyadenylated short DOG1 mRNA is translated in vivo and complements the dog1 mutant. In summary, our findings indicate that the short DOG1 protein isoform produced from the proximally polyadenylated DOG1 mRNA is a key player in the establishment of seed dormancy in Arabidopsis and characterizes a set of mutants in RNA 3' processing complex required for production of proximally polyadenylated functional DOG1 transcript. © 2016 American Society of Plant Biologists. All Rights Reserved.

Metallothionein Isoform Expression in Benign and Malignant Thyroid Lesions.

PubMed

Wojtczak, Beata; Pula, Bartosz; Gomulkiewicz, Agnieszka; Olbromski, Mateusz; Podhorska-Okolow, Marzena; Domoslawski, Paweł; Bolanowski, Marek; Daroszewski, Jacek; Dziegiel, Piotr

2017-09-01

Metallothioneins (MTs) are involved in numerous cell processes such as binding and transport of zinc and copper ions, differentiation, proliferation and apoptosis, therefore contributing to carcinogenesis. Scarce data exist on their expression in benign and malignant lesions of the thyroid. mRNA expression of functional isoforms of MT genes (MT1A, MT1B, MT1E, MT1F, MT1G, MT1H, MT1X, MT2A, MT4) was studied in 17 nodular goiters (NG), 12 follicular adenomas (FA) and 26 papillary thyroid carcinomas (PTC). One-way ANOVA revealed significant differences in mRNA expression levels of MT1A (p<0.05), MT1E (p<0.005), MT1F (p<0.0001), MT1G (p<0.005), MT1X (p<0.0005) and MT2A (p<0.005) in the analyzed samples. Post hoc analysis confirmed a significantly lower expression of MT1A mRNA in PTC compared to NG (p<0.05). Significant down-regulation was also noted for other MT isoforms in PTC in comparison to NG: MT1E (p<0.05), MT1F (p<0.0001), MT1G (p<0.005), MT1X (p<0.0005) and MT2A (p<0.05). In addition, significant down-regulation of MT1F and MT1G in FA compared to NG was observed (p<0.005 and p<0.05, respectively). Expression of functional MT isoforms may contribute to thyroid carcinogenesis and potentially serve as a diagnostic marker in distinguishing benign and malignant lesions. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Proteomics and transcriptomics analyses of Arabidopsis floral buds uncover important functions of ARABIDOPSIS SKP1-LIKE1

DOE PAGES

Lu, Dihong; Ni, Weimin; Stanley, Bruce A.; ...

2016-03-03

The ARABIDOPSIS SKP1-LIKE1 (ASK1) protein functions as a subunit of SKP1-CUL1-F-box (SCF) E3 ubiquitin ligases. Previous genetic studies showed that ASK1 plays important roles in Arabidopsis flower development and male meiosis. However, the molecular impact of ASK1-containing SCF E3 ubiquitin ligases (ASK1-E3s) on the floral proteome and transcriptome is unknown. Here we identified proteins that are potentially regulated by ASK1-E3s by comparing floral bud proteomes of wild-type and the ask1 mutant plants. More than 200 proteins were detected in the ask1 mutant but not in wild-type and >300 were detected at higher levels in the ask1 mutant than in wild-type,more » but their RNA levels were not significantly different between wild-type and ask1 floral buds as shown by transcriptomics analysis, suggesting that they are likely regulated at the protein level by ASK1-E3s. Integrated analyses of floral proteomics and transcriptomics of ask1 and wild-type uncovered several potential aspects of ASK1-E3 functions, including regulation of transcription regulators, kinases, peptidases, and ribosomal proteins, with implications on possible mechanisms of ASK1-E3 functions in floral development. In conclusion, our results suggested that ASK1-E3s play important roles in Arabidopsis protein degradation during flower development. This study opens up new possibilities for further functional studies of these candidate E3 substrates.« less

Proteomics and transcriptomics analyses of Arabidopsis floral buds uncover important functions of ARABIDOPSIS SKP1-LIKE1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Dihong; Ni, Weimin; Stanley, Bruce A.

The ARABIDOPSIS SKP1-LIKE1 (ASK1) protein functions as a subunit of SKP1-CUL1-F-box (SCF) E3 ubiquitin ligases. Previous genetic studies showed that ASK1 plays important roles in Arabidopsis flower development and male meiosis. However, the molecular impact of ASK1-containing SCF E3 ubiquitin ligases (ASK1-E3s) on the floral proteome and transcriptome is unknown. Here we identified proteins that are potentially regulated by ASK1-E3s by comparing floral bud proteomes of wild-type and the ask1 mutant plants. More than 200 proteins were detected in the ask1 mutant but not in wild-type and >300 were detected at higher levels in the ask1 mutant than in wild-type,more » but their RNA levels were not significantly different between wild-type and ask1 floral buds as shown by transcriptomics analysis, suggesting that they are likely regulated at the protein level by ASK1-E3s. Integrated analyses of floral proteomics and transcriptomics of ask1 and wild-type uncovered several potential aspects of ASK1-E3 functions, including regulation of transcription regulators, kinases, peptidases, and ribosomal proteins, with implications on possible mechanisms of ASK1-E3 functions in floral development. In conclusion, our results suggested that ASK1-E3s play important roles in Arabidopsis protein degradation during flower development. This study opens up new possibilities for further functional studies of these candidate E3 substrates.« less

The Arabidopsis halophytic relative Thellungiella halophila tolerates nitrogen-limiting conditions by maintaining growth, nitrogen uptake, and assimilation.

PubMed

Kant, Surya; Bi, Yong-Mei; Weretilnyk, Elizabeth; Barak, Simon; Rothstein, Steven J

2008-07-01

A comprehensive knowledge of mechanisms regulating nitrogen (N) use efficiency is required to reduce excessive input of N fertilizers while maintaining acceptable crop yields under limited N supply. Studying plant species that are naturally adapted to low N conditions could facilitate the identification of novel regulatory genes conferring better N use efficiency. Here, we show that Thellungiella halophila, a halophytic relative of Arabidopsis (Arabidopsis thaliana), grows better than Arabidopsis under moderate (1 mm nitrate) and severe (0.4 mm nitrate) N-limiting conditions. Thellungiella exhibited a lower carbon to N ratio than Arabidopsis under N limitation, which was due to Thellungiella plants possessing higher N content, total amino acids, total soluble protein, and lower starch content compared with Arabidopsis. Furthermore, Thellungiella had higher amounts of several metabolites, such as soluble sugars and organic acids, under N-sufficient conditions (4 mm nitrate). Nitrate reductase activity and NR2 gene expression in Thellungiella displayed less of a reduction in response to N limitation than in Arabidopsis. Thellungiella shoot GS1 expression was more induced by low N than in Arabidopsis, while in roots, Thellungiella GS2 expression was maintained under N limitation but was decreased in Arabidopsis. Up-regulation of NRT2.1 and NRT3.1 expression was higher and repression of NRT1.1 was lower in Thellungiella roots under N-limiting conditions compared with Arabidopsis. Differential transporter gene expression was correlated with higher nitrate influx in Thellungiella at low (15)NO(3)(-) supply. Taken together, our results suggest that Thellungiella is tolerant to N-limited conditions and could act as a model system to unravel the mechanisms for low N tolerance.

Rhenium and technetium tricarbonyl, {M(CO)3} (+) (M = Tc, Re), binding to mammalian metallothioneins: new insights into chemical and radiopharmaceutical implications.

PubMed

Lecina, Joan; Palacios, Òscar; Atrian, Sílvia; Capdevila, Mercè; Suades, Joan

2015-04-01

This paper deals with the binding of the four mammalian metallothioneins (MTs) to the organometallic metal fragment {fac-M(CO)3}(+) (M = (99)Tc, Re), which is highly promising for the preparation of second-generation radiopharmaceuticals. The study of the transmetallation reaction between zinc and rhenium in Zn7-MT1 by means of UV-vis and CD spectroscopy demonstrated the incorporation of the {fac-Re(CO)3}(+) fragment to the MTs. This reaction should be performed at 70 °C to accelerate the reaction rate, a result that is consistent with the reported reactivity of the rhenium fragment. ESI-TOF MS demonstrated the formation of mixed-metal species as Zn6,{Re(CO)3}-MT, Zn6,{Re(CO)3}2-MT, and Zn5,{Re(CO)3}3-MT, as well as the different reactivity of the four MT isoforms. Hence, Zn-MT3 showed the highest reactivity, in agreement with its high Cu-thionein character, whereas Zn-MT2 exhibited the lowest reactivity, in line with its high Zn-thionein character. The reactivity of the Zn-loaded forms of MT1 and MT4 is intermediate between those of MT3 and MT2. The study of the binding of the {fac-(99)Tc(CO)3}(+) fragment to MTs showed a significant and very interesting different reactivity in relation to rhenium. The transmetallation reaction is much more effective with technetium than with rhenium and significant amounts of mixed Zn x ,{(99)Tc(CO)3} y -MT species were formed with the four MT isoforms whereas only MT3 rendered similar amounts of rhenium derivatives. The results obtained in this study support the possible use of technetium for labelling mammalian metallothioneins and also for possible radiopharmaceutical applications.

Multi-Element Bioimaging of Arabidopsis thaliana Roots1[OPEN

PubMed Central

Salt, David E.

2016-01-01

Better understanding of root function is central for the development of plants with more efficient nutrient uptake and translocation. We here present a method for multielement bioimaging at the cellular level in roots of the genetic model system Arabidopsis (Arabidopsis thaliana). Using conventional protocols for microscopy, we observed that diffusible ions such as potassium and sodium were lost during sample dehydration. Thus, we developed a protocol that preserves ions in their native, cellular environment. Briefly, fresh roots are encapsulated in paraffin, cryo-sectioned, and freeze dried. Samples are finally analyzed by laser ablation-inductively coupled plasma-mass spectrometry, utilizing a specially designed internal standard procedure. The method can be further developed to maintain the native composition of proteins, enzymes, RNA, and DNA, making it attractive in combination with other omics techniques. To demonstrate the potential of the method, we analyzed a mutant of Arabidopsis unable to synthesize the metal chelator nicotianamine. The mutant accumulated substantially more zinc and manganese than the wild type in the tissues surrounding the vascular cylinder. For iron, the images looked completely different, with iron bound mainly in the epidermis of the wild-type plants but confined to the cortical cell walls of the mutant. The method offers the power of inductively coupled plasma-mass spectrometry to be fully employed, thereby providing a basis for detailed studies of ion transport in roots. Being applicable to Arabidopsis, the molecular and genetic approaches available in this system can now be fully exploited in order to gain a better mechanistic understanding of these processes. PMID:27566167

Isolation and characterization of metallothioneins in calves ingesting Zn toxic diets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graham, T.W.; Clegg, M.S.; Lonnerdal, B.

1986-03-05

The authors have recently described an outbreak of Zn toxicosis in 95 Holstein bull calves which occurred as a result of an accidental over-supplementation of the diet with Zn. Signs of Zn toxicosis including anorexia, polydipsia, polyphagia, polyurea and diarrhea, began to appear 23 days after initiation of the diet. Liver, kidney, muscle and brain were collected from animals that died or were euthanized. Multielement analysis indicated that liver had the highest concentration of Zn (362 ..mu..g Zn/g wet wt.) followed by kidney (233 ..mu..g Zn/g wet wt.), muscle (22 ..mu..g Zn/g wet wt.) and brain (10 ..mu..g Zn/g wetmore » wt.). To examine the toxic effects of Zn at the molecular level, liver was fractionated by conventional molecular sieve (Sephadex G75) and anion exchange chromatography (DEAE Sephadex A-25). In addition, Fast Protein Liquid Chromatography (FPLC) was used to verify the results obtained by conventional methods. The principle advantages of FPLC are that the molecular sieve (Superose 12) and anion (Mono Q) steps are performed in 1 h as opposed to several hours, thus substantially minimizing artifacts resulting from oxidative degradation of labile proteins. Zn was primarily associated with two peaks, designated metallothionein (MT) I and MT II, in a ratio of 10 to 1. The results show that one effect of Zn toxicity in calves can be a preferential induction of MT I.« less

Interactions of light and ethylene in hypocotyl hook maintenance in Arabidopsis thaliana seedlings

NASA Technical Reports Server (NTRS)

Knee, E. M.; Hangarter, R. P.; Knee, M.

2000-01-01

Etiolated seedlings frequently display a hypocotyl or epicotyl hook which opens on exposure to light. Etylene has been shown to be necessary for maintenance of the hook in a number of plants in darkness. We investigated the interaction of ethylene and light in the regulation of hypocotyl hook opening in Arabidopsis thaliana. We found that hooks of Arabidopsis open in response to continuous red, far-red or blue light in the presence of up to 100 microliters l-1 ethylene. Thus a change in sensitivity to ethylene is likely to be responsible for hook opening in Arabidopsis, rather than a decrease in ethylene production in hook tissues. We used photomorphogenic mutants of Arabidopsis to demonstrate the involvement of both blue light and phytochrome photosensory systems in light-induced hook opening in the presence of ethylene. In addition we used ethylene mutants and inhibitors of ethylene action to investigate the role of ethylene in hook maintenance in seedlings grown in light and darkness.

Imaging lipid droplets in Arabidopsis mutants

USDA-ARS?s Scientific Manuscript database

Confocal fluorescence microscopy was adapted for the imaging of neutral lipids in plant leaves with defects in normal lipid metabolism using two different fluorescent dyes. Disruptions in a gene locus, At4g24160, yielded Arabidopsis thaliana plants with a preponderance of oil bodies in their leaves ...

Glycerolipidome responses to freezing- and chilling-induced injuries: examples in Arabidopsis and rice.

PubMed

Zheng, Guowei; Li, Lixia; Li, Weiqi

2016-03-22

Glycerolipids are the principal constituent of cellular membranes; remodelling of glycerolipids plays important roles in temperature adaptation in plants. Temperate plants can endure freezing stress, but even chilling at above-zero temperatures can induce death in tropical species. However, little is known about the differences in glycerolipid response to low temperatures between chilling-sensitive and freezing-tolerant plants. Using ESI-MS/MS-based lipidomic analysis, we compared the glycerolipidome of chilling (4 and 10 °C)-treated rice with that of freezing (-6 and -12 °C)-treated Arabidopsis, both immediately after these low-temperature treatments and after a subsequent recovery culture period. Arabidopsis is a 16:3 plant that harbours both eukaryotic and prokaryotic-type lipid synthesis pathways, while rice is an 18:3 plant that harbours only the eukaryotic lipid synthesis pathway. Arabidopsis contains higher levels of galactolipids than rice and has a higher double bond index (DBI). Arabidopsis contains lower levels of high melting point phosphatidylglycerol (PG) molecules and has a lower average acyl chain length (ACL). Marked phospholipid degradation occurred during the recovery culture period of non-lethal chilling treated rice, but did not occur in non-lethal freezing treated Arabidopsis. Glycerolipids with larger head groups were synthesized more in Arabidopsis than in rice at sub-lethal low-temperatures. Levels of phosphatidic acid (PA) and phosphatidylinositol (PI) rose in both plants after low-temperature treatment. The DBI and ACL of total lipids did not change during low-temperature treatment. A higher DBI and a lower ACL could make the membranes of Arabidopsis more fluid at low temperatures. The ability to synthesize glycerolipids containing a larger head group may correlate with low-temperature tolerance. The low-temperature-induced increase of PA may play a dual role in plant responses to low temperatures: as a lipid signal that initiates

Metallothionein quantification in clams by reversed-phase high-performance liquid chromatography coupled to fluorescence detection after monobromobimane derivatization.

PubMed

Alhama, José; Romero-Ruiz, Antonio; López-Barea, Juan

2006-02-24

In this paper, we describe a highly specific, sensitive and reliable method for total metallothionein (MT) quantification by RP-HPLC coupled to fluorescence detection following reaction with monobromobimane of thiols from metal-depleted MT after heat-denaturation of extracts in the presence of sodium dodecyl sulphate (SDS). SDS-polyacrylamide gel electrophoresis (SDS-PAGE) confirmed the identity of the peak resolved (t(R)=16.44) with MT: a highly fluorescent protein of approximately 8.3 kDa, in agreement with the high thiol content and low MT size. Other heat-resistant and Cys-containing proteins of 35 kDa were efficiently separated. The new method was successfully used to quantify MT content in digestive gland of clams from southern Spanish coastal sites with different metal levels, and is proposed as a tool for using MTs as biomarker in monitoring programmes.

Trace-elements, methylmercury and metallothionein levels in Magellanic penguin (Spheniscus magellanicus) found stranded on the Southern Brazilian coast.

PubMed

Kehrig, Helena A; Hauser-Davis, Rachel A; Seixas, Tércia G; Fillmann, Gilberto

2015-07-15

Magellanic penguins have been reported as good biomonitors for several types of pollutants, including trace-elements. In this context, selenium (Se), total mercury, methylmercury, inorganic mercury (Hg(inorg)), cadmium (Cd) and lead (Pb), as well as metallothionein (MT) levels, were evaluated in the feathers, liver and kidney of juvenile Magellanic penguins found stranded along the coast of Southern Brazil. The highest concentrations of all trace-elements and methylmercury were found in internal organs. Concentrations of Cd and Se in feathers were extremely low in comparison with their concentrations in soft tissues. The results showed that both Se and MT are involved in the detoxification of trace-elements (Cd, Pb and Hg(inorg)) since statistically significant relationships were found in liver. Conversely, hepatic Se was shown to be the only detoxifying agent for methylmercury. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gibberellic Acid-Stimulated Arabidopsis6 Serves as an Integrator of Gibberellin, Abscisic Acid, and Glucose Signaling during Seed Germination in Arabidopsis.

PubMed

Zhong, Chunmei; Xu, Hao; Ye, Siting; Wang, Shiyi; Li, Lingfei; Zhang, Shengchun; Wang, Xiaojing

2015-11-01

The DELLA protein REPRESSOR OF ga1-3-LIKE2 (RGL2) plays an important role in seed germination under different conditions through a number of transcription factors. However, the functions of the structural genes associated with RGL2-regulated germination are less defined. Here, we report the role of an Arabidopsis (Arabidopsis thaliana) cell wall-localized protein, Gibberellic Acid-Stimulated Arabidopsis6 (AtGASA6), in functionally linking RGL2 and a cell wall loosening expansin protein (Arabidopsis expansin A1 [AtEXPA1]), resulting in the control of embryonic axis elongation and seed germination. AtGASA6-overexpressing seeds showed precocious germination, whereas transfer DNA and RNA interference mutant seeds displayed delayed seed germination under abscisic acid, paclobutrazol, and glucose (Glc) stress conditions. The differences in germination rates resulted from corresponding variation in cell elongation in the hypocotyl-radicle transition region of the embryonic axis. AtGASA6 was down-regulated by RGL2, GLUCOSE INSENSITIVE2, and ABSCISIC ACID-INSENSITIVE5 genes, and loss of AtGASA6 expression in the gasa6 mutant reversed the insensitivity shown by the rgl2 mutant to paclobutrazol and the gin2 mutant to Glc-induced stress, suggesting that it is involved in regulating both the gibberellin and Glc signaling pathways. Furthermore, it was found that the promotion of seed germination and length of embryonic axis by AtGASA6 resulted from a promotion of cell elongation at the embryonic axis mediated by AtEXPA1. Taken together, the data indicate that AtGASA6 links RGL2 and AtEXPA1 functions and plays a role as an integrator of gibberellin, abscisic acid, and Glc signaling, resulting in the regulation of seed germination through a promotion of cell elongation. © 2015 American Society of Plant Biologists. All Rights Reserved.

Individualism in plant populations: using stochastic differential equations to model individual neighbourhood-dependent plant growth.

PubMed

Lv, Qiming; Schneider, Manuel K; Pitchford, Jonathan W

2008-08-01

We study individual plant growth and size hierarchy formation in an experimental population of Arabidopsis thaliana, within an integrated analysis that explicitly accounts for size-dependent growth, size- and space-dependent competition, and environmental stochasticity. It is shown that a Gompertz-type stochastic differential equation (SDE) model, involving asymmetric competition kernels and a stochastic term which decreases with the logarithm of plant weight, efficiently describes individual plant growth, competition, and variability in the studied population. The model is evaluated within a Bayesian framework and compared to its deterministic counterpart, and to several simplified stochastic models, using distributional validation. We show that stochasticity is an important determinant of size hierarchy and that SDE models outperform the deterministic model if and only if structural components of competition (asymmetry; size- and space-dependence) are accounted for. Implications of these results are discussed in the context of plant ecology and in more general modelling situations.

Arabidopsis SEIPIN Proteins Modulate Triacylglycerol Accumulation and Influence Lipid Droplet Proliferation

DOE PAGES

Cai, Yingqi; Goodman, Joel M.; Pyc, Michal; ...

2015-09-01

The lipodystrophy protein SEIPIN is important for lipid droplet (LD) biogenesis in human and yeast cells. In contrast with the single SEIPIN genes in humans and yeast, there are three SEIPIN homologs in Arabidopsis thaliana, designated SEIPIN1, SEIPIN2, and SEIPIN3. Essentially nothing is known about the functions of SEIPIN homologs in plants. Here, a yeast (Saccharomyces cerevisiae) SEIPIN deletion mutant strain and a plant (Nicotiana benthamiana) transient expression system were used to test the ability of Arabidopsis SEIPINs to influence LD morphology. In both species, expression of SEIPIN1 promoted accumulation of large-sized lipid droplets, while expression of SEIPIN2 and especiallymore » SEIPIN3 promoted small LDs. Arabidopsis SEIPINs increased triacylglycerol levels and altered composition. In tobacco, endoplasmic reticulum (ER)-localized SEIPINs reorganized the normal, reticulated ER structure into discrete ER domains that colocalized with LDs. N-terminal deletions and swapping experiments of SEIPIN1 and 3 revealed that this region of SEIPIN determines LD size. Ectopic overexpression of SEIPIN1 in Arabidopsis resulted in increased numbers of large LDs in leaves, as well as in seeds, and increased seed oil content by up to 10% over wild-type seeds. By contrast, RNAi suppression of SEIPIN1 resulted in smaller seeds and, as a consequence, a reduction in the amount of oil per seed compared with the wild type. Finally, overall, our results indicate that Arabidopsis SEIPINs are part of a conserved LD biogenesis machinery in eukaryotes and that in plants these proteins may have evolved specialized roles in the storage of neutral lipids by differentially modulating the number and sizes of lipid droplets.« less

TEA: the epigenome platform for Arabidopsis methylome study.

PubMed

Su, Sheng-Yao; Chen, Shu-Hwa; Lu, I-Hsuan; Chiang, Yih-Shien; Wang, Yu-Bin; Chen, Pao-Yang; Lin, Chung-Yen

2016-12-22

Bisulfite sequencing (BS-seq) has become a standard technology to profile genome-wide DNA methylation at single-base resolution. It allows researchers to conduct genome-wise cytosine methylation analyses on issues about genomic imprinting, transcriptional regulation, cellular development and differentiation. One single data from a BS-Seq experiment is resolved into many features according to the sequence contexts, making methylome data analysis and data visualization a complex task. We developed a streamlined platform, TEA, for analyzing and visualizing data from whole-genome BS-Seq (WGBS) experiments conducted in the model plant Arabidopsis thaliana. To capture the essence of the genome methylation level and to meet the efficiency for running online, we introduce a straightforward method for measuring genome methylation in each sequence context by gene. The method is scripted in Java to process BS-Seq mapping results. Through a simple data uploading process, the TEA server deploys a web-based platform for deep analysis by linking data to an updated Arabidopsis annotation database and toolkits. TEA is an intuitive and efficient online platform for analyzing the Arabidopsis genomic DNA methylation landscape. It provides several ways to help users exploit WGBS data. TEA is freely accessible for academic users at: http://tea.iis.sinica.edu.tw .

Apoplastic polyesters in Arabidopsis surface tissues--a typical suberin and a particular cutin.

PubMed

Franke, Rochus; Briesen, Isabel; Wojciechowski, Tobias; Faust, Andrea; Yephremov, Alexander; Nawrath, Christiane; Schreiber, Lukas

2005-11-01

Cutinized and suberized cell walls form physiological important plant-environment interfaces as they act as barriers limiting water and nutrient loss and protect from radiation and invasion by pathogens. Due to the lack of protocols for the isolation and analysis of cutin and suberin in Arabidopsis, the model plant for molecular biology, mutants and transgenic plants with a defined altered cutin or suberin composition are unavailable, causing that structure and function of these apoplastic barriers are still poorly understood. Transmission electron microscopy (TEM) revealed that Arabidopsis leaf cuticle thickness ranges from only 22 nm in leaf blades to 45 nm on petioles, causing the difficulty in cuticular membrane isolation. We report the use of polysaccharide hydrolases to isolate Arabidopsis cuticular membranes, suitable for depolymerization and subsequent compositional analysis. Although cutin characteristic omega-hydroxy acids (7%) and mid-chain hydroxylated fatty acids (8%) were detected, the discovery of alpha,omega-diacids (40%) and 2-hydroxy acids (14%) as major depolymerization products reveals a so far novel monomer composition in Arabidopsis cutin, but with chemical analogy to root suberin. Histochemical and TEM analysis revealed that suberin depositions were localized to the cell walls in the endodermis of primary roots and the periderm of mature roots of Arabidopsis. Enzyme digested and solvent extracted root cell walls when subjected to suberin depolymerization conditions released omega-hydroxy acids (43%) and alpha,omega-diacids (24%) as major components together with carboxylic acids (9%), alcohols (6%) and 2-hydroxyacids (0.1%). This similarity to suberin of other species indicates that Arabidopsis roots can serve as a model for suberized tissue in general.

Basipetal auxin transport is required for gravitropism in roots of Arabidopsis

NASA Technical Reports Server (NTRS)

Rashotte, A. M.; Brady, S. R.; Reed, R. C.; Ante, S. J.; Muday, G. K.; Davies, E. (Principal Investigator)

2000-01-01

Auxin transport has been reported to occur in two distinct polarities, acropetally and basipetally, in two different root tissues. The goals of this study were to determine whether both polarities of indole-3-acetic acid (IAA) transport occur in roots of Arabidopsis and to determine which polarity controls the gravity response. Global application of the auxin transport inhibitor naphthylphthalamic acid (NPA) to roots blocked the gravity response, root waving, and root elongation. Immediately after the application of NPA, the root gravity response was completely blocked, as measured by an automated video digitizer. Basipetal [(3)H]IAA transport in Arabidopsis roots was inhibited by NPA, whereas the movement of [(14)C]benzoic acid was not affected. Inhibition of basipetal IAA transport by local application of NPA blocked the gravity response. Inhibition of acropetal IAA transport by application of NPA at the root-shoot junction only partially reduced the gravity response at high NPA concentrations. Excised root tips, which do not receive auxin from the shoot, exhibited a normal response to gravity. The Arabidopsis mutant eir1, which has agravitropic roots, exhibited reduced basipetal IAA transport but wild-type levels of acropetal IAA transport. These results support the hypothesis that basipetally transported IAA controls root gravitropism in Arabidopsis.

Neuroprotective effects of metallothionein against rotenone-induced myenteric neurodegeneration in parkinsonian mice.

PubMed

Murakami, Shinki; Miyazaki, Ikuko; Sogawa, Norio; Miyoshi, Ko; Asanuma, Masato

2014-10-01

Parkinson's disease (PD) is a neurodegenerative disease with motor symptoms as well as non-motor symptoms that precede the onset of motor symptoms. Mitochondrial complex I inhibitor, rotenone, has been widely used to reproduce PD pathology in the central nervous system (CNS) and enteric nervous system (ENS). We reported previously that metallothioneins (MTs) released from astrocytes can protect dopaminergic neurons against oxidative stress. The present study examined the changes in MT expression by chronic systemic rotenone administration in the striatum and colonic myenteric plexus of C57BL mice. In addition, we investigated the effects of MT depletion on rotenone-induced neurodegeneration in CNS and ENS using MT-1 and MT-2 knockout (MT KO) mice, or using primary cultured neurons from MT KO mice. In normal C57BL mice, subcutaneous administration of rotenone for 6 weeks caused neurodegeneration, increased MT expression with astrocytes activation in the striatum and myenteric plexus. MT KO mice showed more severe myenteric neuronal damage by rotenone administration after 4 weeks than wild-type mice, accompanied by reduced astroglial activation. In primary cultured mesencephalic neurons from MT KO mice, rotenone exposure induced neurotoxicity in dopaminergic neurons, which was complemented by addition of recombinant protein. The present results suggest that MT seems to provide protection against neurodegeneration in ENS of rotenone-induced PD model mice.

The Functions of Metallothionein and ZIP and ZnT Transporters: An Overview and Perspective

PubMed Central

Kimura, Tomoki; Kambe, Taiho

2016-01-01

Around 3000 proteins are thought to bind zinc in vivo, which corresponds to ~10% of the human proteome. Zinc plays a pivotal role as a structural, catalytic, and signaling component that functions in numerous physiological processes. It is more widely used as a structural element in proteins than any other transition metal ion, is a catalytic component of many enzymes, and acts as a cellular signaling mediator. Thus, it is expected that zinc metabolism and homeostasis have sophisticated regulation, and elucidating the underlying molecular basis of this is essential to understanding zinc functions in cellular physiology and pathogenesis. In recent decades, an increasing amount of evidence has uncovered critical roles of a number of proteins in zinc metabolism and homeostasis through influxing, chelating, sequestrating, coordinating, releasing, and effluxing zinc. Metallothioneins (MT) and Zrt- and Irt-like proteins (ZIP) and Zn transporters (ZnT) are the proteins primarily involved in these processes, and their malfunction has been implicated in a number of inherited diseases such as acrodermatitis enteropathica. The present review updates our current understanding of the biological functions of MTs and ZIP and ZnT transporters from several new perspectives. PMID:26959009

Correlative controls of senescence and plant death in Arabidopsis thaliana (Brassicaceae).

PubMed

Noodén, L D; Penney, J P

2001-11-01

Like most monocarpic plants, longevity of Arabidopsis thaliana plants is controlled by the reproductive structures; however, they appear to work differently from most dicots studied. Neither male- and female-sterility mutations (ms1-1 and bell1, respectively) nor surgical removal of the stems with inflorescences (bolts) at various stages significantly increased the longevity of individual rosette leaves, yet the mutants and treated plants lived 20-50 d longer, measured by the death of the last rosette and/or the last cauline leaf. A series of growth mutations (clv2-4, clv3-2, det3, vam1 enh, and dark green) also increased plant longevity by 20-30 d but did not delay the overall development of the plants. The mutations prolonged plant life through the production of new leaves and stems with inflorescences (bolts) rather than by extending leaf longevity. In growing stems, the newly-formed leaves may induce senescence in the older leaves; however, removal of the younger leaves did not significantly increase the life of the older leaves on the compressed stems of Arabidopsis. Since plants that produce more bolts also live longer, the reproductive load (dry weight) of the bolts did not seem to drive leaf or whole plant senescence here. The developing reproductive structures caused the death of the plant by preventing regeneration of leaves and bolts, which are green and presumably photosynthetic. They also exerted a correlative control (repression) on the development of additional reproductive structures.

PAUSED encodes the Arabidopsis exportin-t ortholog.

PubMed

Hunter, Christine A; Aukerman, Milo J; Sun, Hui; Fokina, Maria; Poethig, R Scott

2003-08-01

Los1p/exportin-t (XPOT) mediates the nuclear export of tRNAs in yeast and mammals. The requirements for this transport pathway are unclear, however, because los1 mutations do not affect yeast growth, and the phenotype of XPOT mutations in mammals is unknown. Here, we show that PAUSED (PSD) is the Arabidopsis ortholog of LOS1/XPOT and is capable of rescuing the tRNA export defect of los1 in Brewer's yeast (Saccharomyces cerevisiae), suggesting that its function has been conserved. Putative null alleles of PSD disrupt the initiation of the shoot apical meristem and delay leaf initiation after germination, the emergence of the radicle and lateral roots, and the transition to flowering. Plants doubly mutant for psd and hasty, the Arabidopsis ortholog of exportin 5, are viable but have a more severe phenotype than either single mutant. These results suggest that PSD plays a role in tRNA export in Arabidopsis, but that at least one-and perhaps several-additional tRNA export pathways also exist. The PSD transcript is broadly expressed during development and is alternatively spliced in the 3'-untranslated region. No temporal or spatial difference in the abundance of different splice forms was observed. We propose that the mutant phenotype of psd reflects defects in developmental events and cell/tissue types that require elevated levels of protein synthesis and are therefore acutely sensitive to a reduction in tRNA export.

Functional analysis of the Hikeshi-like protein and its interaction with HSP70 in Arabidopsis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koizumi, Shinya; Ohama, Naohiko; Mizoi, Junya

2014-07-18

Highlights: • HKL, a Hikeshi homologous gene is identified in Arabidopsis. • HKL interacts with two HSP70 isoforms and regulates the subcellular localization of HSC70-1. • The two HSP70 translocate into nucleus in response to heat stress. • Overexpression of HKL confers thermotolerance in transgenic plants. - Abstract: Heat shock proteins (HSPs) refold damaged proteins and are an essential component of the heat shock response. Previously, the 70 kDa heat shock protein (HSP70) has been reported to translocate into the nucleus in a heat-dependent manner in many organisms. In humans, the heat-induced translocation of HSP70 requires the nuclear carrier proteinmore » Hikeshi. In the Arabidopsis genome, only one gene encodes a protein with high homology to Hikeshi, and we named this homolog Hikeshi-like (HKL) protein. In this study, we show that two Arabidopsis HSP70 isoforms accumulate in the nucleus in response to heat shock and that HKL interacts with these HSP70s. Our histochemical analysis revealed that HKL is predominantly expressed in meristematic tissues, suggesting the potential importance of HKL during cell division in Arabidopsis. In addition, we show that HKL regulates HSP70 localization, and HKL overexpression conferred thermotolerance to transgenic Arabidopsis plants. Our results suggest that HKL plays a positive role in the thermotolerance of Arabidopsis plants and cooperatively interacts with HSP70.« less

The Cultivation of Arabidopsis for Experimental Research Using Commercially Available Peat-Based and Peat-Free Growing Media

PubMed Central

Drake, Tiffany; Keating, Mia; Summers, Rebecca; Yochikawa, Aline; Pitman, Tom

2016-01-01

Experimental research involving Arabidopsis thaliana often involves the quantification of phenotypic traits during cultivation on compost or other growing media. Many commercially-available growing media contain peat, but peat extraction is not sustainable due to its very slow rate of formation. Moreover, peat extraction reduces peatland biodiversity and releases stored carbon and methane into the atmosphere. Here, we compared the experimental performance of Arabidopsis on peat-based and several types of commercially-available peat-free growing media (variously formed from coir, composted bark, wood-fibre, and domestic compost), to provide guidance for reducing peat use in plant sciences research with Arabidopsis. Arabidopsis biomass accumulation and seed yield were reduced by cultivation on several types of peat-free growing media. Arabidopsis performed extremely poorly on coir alone, presumably because this medium was completely nitrate-free. Some peat-free growing media were more susceptible to fungal contamination. We found that autoclaving of control (peat-based) growing media had no effect upon any physiological parameters that we examined, compared with non-autoclaved control growing media, under our experimental conditions. Overall, we conclude that Arabidopsis performs best when cultivated on peat-based growing media because seed yield was almost always reduced when peat-free media were used. This may be because standard laboratory protocols and growth conditions for Arabidopsis are optimized for peat-based media. However, during the vegetative growth phase several phenotypic traits were comparable between plants cultivated on peat-based and some peat-free media, suggesting that under certain circumstances peat-free media can be suitable for phenotypic analysis of Arabidopsis. PMID:27088495

The Arabidopsis-related halophyte Thellungiella halophila: boron tolerance via boron complexation with metabolites?

PubMed

Lamdan, Netta Li; Attia, Ziv; Moran, Nava; Moshelion, Menachem

2012-04-01

Tolerance to boron (B) is still not completely understood. We tested here the hypothesis that Thellungiella halophila, an Arabidopsis thaliana-related 'extremophile' plant, with abundance of B in its natural environment, is tolerant to B, and examined the potential mechanisms of this tolerance. With 1-10 mm B applied ([B](ext)) to Thellungiella and Arabidopsis grown in hydroponics, the steady-state accumulated B concentration ([B](int)) in the root was below [B](ext), and was similar in both, suggesting both extrude B actively. Whether grown in soil or hydroponically, the shoot [B](int) was higher in Arabidopsis than in Thellungiella, suggesting more effective net B exclusion by Thellungiella root. Arabidopsis exhibited toxicity symptoms including reduced shoot fresh weight (FW), but Thellungiella was not affected, even at similar levels of shoot-accumulated [B](int) (about 10 to 40 mm B in 'shoot water'), suggesting additional B tolerance mechanism in Thellungiella shoot. At [B](ext) = 5 mm, the summed shoot concentration of the potentially B-binding polyhydroxyl metabolites (malic acid, fructose, glucose, sucrose and citric acid) in Arabidopsis was below [B](int) , but in Thellungiella it was over twofold higher than [B](int) , and therefore likely to allow appreciable 1:2 boron-metabolite complexation in the shoot. This, we suggest, is an important component of Thellungiella B tolerance mechanism. © 2011 Blackwell Publishing Ltd.

Overexpression of a bacterial mercury transporter MerT in Arabidopsis enhances mercury tolerance.

PubMed

Xu, Sheng; Sun, Bin; Wang, Rong; He, Jia; Xia, Bing; Xue, Yong; Wang, Ren

2017-08-19

The phytoremediation by using of green plants in the removal of environmental pollutant is an environment friendly, green technology that is cost effective and energetically inexpensive. By using Agrobacterium-mediated gene transfer, we generated transgenic Arabidopsis plants ectopically expressing mercuric transport protein gene (merT) from Pseudomonas alcaligenes. Compared with wild-type (WT) plants, overexpressing PamerT in Arabidopsis enhanced the tolerance to HgCl 2 . Further results showed that the enhanced total activities or corresponding transcripts of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (POD) were observed in transgenic Arabidopsis under HgCl 2 stress. These results were confirmed by the alleviation of oxidative damage, as indicated by the decrease of thiobarbituric acid reactive substances (TBARS) contents and reactive oxygen species (ROS) accumulation. In addition, localization analysis of PaMerT in Arabidopsis protoplast showed that it is likely to be associated with vacuole. In all, PamerT increased mercury (Hg) tolerance in transgenic Arabidopsis, and decreased production of Hg-induced ROS, thereby protecting plants from oxidative damage. The present study has provided further evidence that bacterial MerT plays an important role in the plant tolerance to HgCl 2 and in reducing the production of ROS induced by HgCl 2 . Copyright © 2017 Elsevier Inc. All rights reserved.

The Triple Response Assay and Its Use to Characterize Ethylene Mutants in Arabidopsis.

PubMed

Merchante, Catharina; Stepanova, Anna N

2017-01-01

Exposure of plants to ethylene results in drastic morphological changes. Seedlings germinated in the dark in the presence of saturating concentrations of ethylene display a characteristic phenotype known as the triple response. This phenotype is robust and easy to score. In Arabidopsis the triple response is usually evaluated at 3 days post germination in seedlings grown in the dark in rich media supplemented with 10 μM of the ethylene precursor ACC in air or in unsupplemented media in the presence of 10 ppm ethylene. The triple response in Arabidopsis consists of shortening and thickening of hypocotyls and roots and exaggeration of the curvature of apical hooks. The search for Arabidopsis mutants that fail to show this phenotype in ethylene or, vice versa, display the triple response in the absence of exogenously supplied hormone has allowed the identification of the key components of the ethylene biosynthesis and signaling pathways. Herein, we describe a simple protocol for assaying the triple response in Arabidopsis. The method can also be employed in many other dicot species, with minor modifications to account for species-specific differences in germination. We also compiled a comprehensive table of ethylene-related mutants of Arabidopsis, including many lines with auxin-related defects, as wild-type levels of auxin biosynthesis, transport, signaling, and response are necessary for the normal response of plants to ethylene.

Metallothionein expression in chloroplasts enhances mercury accumulation and phytoremediation capability

PubMed Central

Ruiz, Oscar N.; Alvarez, Derry; Torres, Cesar; Roman, Laura; Daniell, Henry

2015-01-01

Summary Genetic engineering to enhance mercury phytoremediation has been accomplished by expression of the merAB genes that protects the cell by converting Hg[II] into Hg[0] which volatilizes from the cell. A drawback of this approach is that toxic Hg is released back into the environment. A better phytoremediation strategy would be to accumulate mercury inside plants for subsequent retrieval. We report here the development of a transplastomic approach to express the mouse metallothionein gene (mt1) and accumulate mercury in high concentrations within plant cells. Real-time PCR analysis showed that up to 1284 copies of the mt1 gene were found per cell when compared with 1326 copies of the 16S rrn gene, thereby attaining homoplasmy. Past studies in chloroplast transformation used qualitative Southern blots to evaluate indirectly transgene copy number, whereas we used real-time PCR for the first time to establish homoplasmy and estimate transgene copy number and transcript levels. The mt1 transcript levels were very high with 183 000 copies per ng of RNA or 41% the abundance of the 16S rrn transcripts. The transplastomic lines were resistant up to 20 μm mercury and maintained high chlorophyll content and biomass. Although the transgenic plants accumulated high concentrations of mercury in all tissues, leaves accumulated up to 106 ng, indicating active phytoremediation and translocation of mercury. Such accumulation of mercury in plant tissues facilitates proper disposal or recycling. This study reports, for the first time, the use of metallothioniens in plants for mercury phytoremediation. Chloroplast genetic engineering approach is useful to express metal-scavenging proteins for phytoremediation. PMID:21518240

Seed-to-seed growth of Arabidopsis thaliana on the International Space Station

NASA Technical Reports Server (NTRS)

Link, B. M.; Durst, S. J.; Zhou, W.; Stankovic, B.

2003-01-01

The assembly of the International Space Station (ISS) as a permanent experimental outpost has provided the opportunity for quality plant research in space. To take advantage of this orbital laboratory, engineers and scientists at the Wisconsin Center for Space Automation and Robotics (WCSAR), University of Wisconsin-Madison, developed a plant growth facility capable of supporting plant growth in the microgravity environment. Utilizing this Advanced Astroculture (ADVASC) plant growth facility, an experiment was conducted with the objective to grow Arabidopsis thaliana plants from seed-to-seed on the ISS. Dry Arabidopsis seeds were anchored in the root tray of the ADVASC growth chamber. These seeds were successfully germinated from May 10 until the end of June 2001. Arabidopsis plants grew and completed a full life cycle in microgravity. This experiment demonstrated that ADVASC is capable of providing environment conditions suitable for plant growth and development in microgravity. The normal progression through the life cycle, as well as the postflight morphometric analyses, demonstrate that Arabidopsis thaliana does not require the presence of gravity for growth and development. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Immunolocalization of integrin-like proteins in Arabidopsis and Chara

NASA Technical Reports Server (NTRS)

Katembe, W. J.; Swatzell, L. J.; Makaroff, C. A.; Kiss, J. Z.

1997-01-01

Integrins are a large family of integral plasma membrane proteins that link the extracellular matrix to the cytoskeleton in animal cells. As a first step in determining if integrin-like proteins are involved in gravitropic signal transduction pathways, we have used a polyclonal antibody against the chicken beta1 integrin subunit in western blot analyses and immunofluorescence microscopy to gain information on the size and location of these proteins in plants. Several different polypeptides are recognized by the anti-integrin antibody in roots and shoots of Arabidopsis and in the internodal cells and rhizoids of Chara. These cross-reactive polypeptides are associated with cellular membranes, a feature which is consistent with the known location of integrins in animal systems. In immunofluorescence studies of Arabidopsis roots, a strong signal was obtained from labeling integrin-like proteins in root cap cells, and there was little or no immunolabel in other regions of the root tip. While the antibody stained throughout Chara rhizoids, the highest density of immunolabel was at the tip. Thus, in both Arabidopsis roots and Chara rhizoids, the sites of gravity perception/transduction appear to be enriched in integrin-like molecules.

Biosynthesis and Metabolic Engineering of Anthocyanins in Arabidopsis thaliana

PubMed Central

Shi, Ming-Zhu; Xie, De-Yu

2014-01-01

Arabidopsis thaliana is the first model plant, the genome of which has been sequenced. In general, intensive studies on this model plant over the past nearly 30 years have led to many new revolutionary understandings in every single aspect of plant biology. Here, we review the current understanding of anthocyanin biosynthesis in this model plant. Although the investigation of anthocyanin structures in this model plant was not performed until 2002, numerous studies over the past three decades have been conducted to understand the biosynthesis of anthocyanins. To date, it appears that all pathway genes of anthocyanins have been molecularly, genetically and biochemically characterized in this plant. These fundamental accomplishments have made Arabidopsis an ideal model to understand the regulatory mechanisms of anthocyanin pathway. Several studies have revealed that the biosynthesis of anthocyanins is controlled by WD40-bHLH-MYB (WBM) transcription factor complexes under lighting conditions. However, how different regulatory complexes coordinately and specifically regulate the pathway genes of anthocyanins remains unclear. In this review, we discuss current progresses and findings including structural diversity, regulatory properties and metabolic engineering of anthocyanins in Arabidopsis thaliana. PMID:24354533

Spermine modulates the expression of two probable polyamine transporter genes and determines growth responses to cadaverine in Arabidopsis.

PubMed

Sagor, G H M; Berberich, Thomas; Kojima, Seiji; Niitsu, Masaru; Kusano, Tomonobu

2016-06-01

Two genes, LAT1 and OCT1 , are likely to be involved in polyamine transport in Arabidopsis. Endogenous spermine levels modulate their expression and determine the sensitivity to cadaverine. Arabidopsis spermine (Spm) synthase (SPMS) gene-deficient mutant was previously shown to be rather resistant to the diamine cadaverine (Cad). Furthermore, a mutant deficient in polyamine oxidase 4 gene, accumulating about twofold more of Spm than wild type plants, showed increased sensitivity to Cad. It suggests that endogenous Spm content determines growth responses to Cad in Arabidopsis thaliana. Here, we showed that Arabidopsis seedlings pretreated with Spm absorbs more Cad and has shorter root growth, and that the transgenic Arabidopsis plants overexpressing the SPMS gene are hypersensitive to Cad, further supporting the above idea. The transgenic Arabidopsis overexpressing L-Amino acid Transporter 1 (LAT1) absorbed more Cad and showed increased Cad sensitivity, suggesting that LAT1 functions as a Cad importer. Recently, other research group reported that Organic Cation Transporter 1 (OCT1) is a causal gene which determines the Cad sensitivity of various Arabidopsis accessions. Furthermore, their results suggested that OCT1 is involved in Cad efflux. Thus we monitored the expression of OCT1 and LAT1 during the above experiments. Based on the results, we proposed a model in which the level of Spm content modulates the expression of OCT1 and LAT1, and determines Cad sensitivity of Arabidopsis.

Growing Arabidopsis in vitro: cell suspensions, in vitro culture, and regeneration.

PubMed

Barkla, Bronwyn J; Vera-Estrella, Rosario; Pantoja, Omar

2014-01-01

An understanding of basic methods in Arabidopsis tissue culture is beneficial for any laboratory working on this model plant. Tissue culture refers to the aseptic growth of cells, organs, or plants in a controlled environment, in which physical, nutrient, and hormonal conditions can all be easily manipulated and monitored. The methodology facilitates the production of a large number of plants that are genetically identical over a relatively short growth period. Techniques, including callus production, cell suspension cultures, and plant regeneration, are all indispensable tools for the study of cellular biochemical and molecular processes. Plant regeneration is a key technology for successful stable plant transformation, while cell suspension cultures can be exploited for metabolite profiling and mining. In this chapter we report methods for the successful and highly efficient in vitro regeneration of plants and production of stable cell suspension lines from leaf explants of both Arabidopsis thaliana and Arabidopsis halleri.

The epigenetic control of the Athila family of retrotransposons in Arabidopsis.

PubMed

Slotkin, R Keith

2010-08-16

Retrotransposons are major constituents of both plant and animal genomes. In the genome of the model plant Arabidopsis thaliana, which is known for its small size and low repeat content, the Athila retrotransposon family occupies over 2.7% of the total genome and is a major building block of the centromere. However, the copy number and location of Athila elements fail to tell the complete story, as recent experiments have demonstrated that Athila is not only literally at the center of each chromosome, but figuratively at the center of Arabidopsis epigenetic regulation. The silencing of Athila retrotransposons has come to the forefront of Arabidopsis small RNA regulation, the control of the centromere core, as well as potentially playing a role in speciation. This review explores what studying one of the largest transposable element families in one of the smallest plant genomes can tell us about the epigenetic regulation of the genome.

Analyses of Old “Prokaryotic” Proteins Indicate Functional Diversification in Arabidopsis and Oryza sativa

PubMed Central

Singh, Anupama; Jethva, Minesh; Singla-Pareek, Sneh L.; Pareek, Ashwani; Kushwaha, Hemant R.

2016-01-01

During evolution, various processes such as duplication, divergence, recombination, and many other events leads to the evolution of new genes with novel functions. These evolutionary events, thus significantly impact the evolution of cellular, physiological, morphological, and other phenotypic trait of organisms. While evolving, eukaryotes have acquired large number of genes from the earlier prokaryotes. This work is focused upon identification of old “prokaryotic” proteins in Arabidopsis and Oryza sativa genome, further highlighting their possible role(s) in the two genomes. Our results suggest that with respect to their genome size, the fraction of old “prokaryotic” proteins is higher in Arabidopsis than in Oryza sativa. The large fractions of such proteins encoding genes were found to be localized in various endo-symbiotic organelles. The domain architecture of the old “prokaryotic” proteins revealed similar distribution in both Arabidopsis and Oryza sativa genomes showing their conserved evolution. In Oryza sativa, the old “prokaryotic” proteins were more involved in developmental processes, might be due to constant man-made selection pressure for better agronomic traits/productivity. While in Arabidopsis, these proteins were involved in metabolic functions. Overall, the analysis indicates the distinct pattern of evolution of old “prokaryotic” proteins in Arabidopsis and Oryza sativa. PMID:27014324

Arabidopsis CPR5 regulates ethylene signaling via molecular association with the ETR1 receptor.

PubMed

Wang, Feifei; Wang, Lijuan; Qiao, Longfei; Chen, Jiacai; Pappa, Maria Belen; Pei, Haixia; Zhang, Tao; Chang, Caren; Dong, Chun-Hai

2017-11-01

The plant hormone ethylene plays various functions in plant growth, development and response to environmental stress. Ethylene is perceived by membrane-bound ethylene receptors, and among the homologous receptors in Arabidopsis, the ETR1 ethylene receptor plays a major role. The present study provides evidence demonstrating that Arabidopsis CPR5 functions as a novel ETR1 receptor-interacting protein in regulating ethylene response and signaling. Yeast split ubiquitin assays and bi-fluorescence complementation studies in plant cells indicated that CPR5 directly interacts with the ETR1 receptor. Genetic analyses indicated that mutant alleles of cpr5 can suppress ethylene insensitivity in both etr1-1 and etr1-2, but not in other dominant ethylene receptor mutants. Overexpression of Arabidopsis CPR5 either in transgenic Arabidopsis plants, or ectopically in tobacco, significantly enhanced ethylene sensitivity. These findings indicate that CPR5 plays a critical role in regulating ethylene signaling. CPR5 is localized to endomembrane structures and the nucleus, and is involved in various regulatory pathways, including pathogenesis, leaf senescence, and spontaneous cell death. This study provides evidence for a novel regulatory function played by CPR5 in the ethylene receptor signaling pathway in Arabidopsis. © 2017 Institute of Botany, Chinese Academy of Sciences.

Zinc rescues obesity-induced cardiac hypertrophy via stimulating metallothionein to suppress oxidative stress-activated BCL10/CARD9/p38 MAPK pathway.

PubMed

Wang, Shudong; Gu, Junlian; Xu, Zheng; Zhang, Zhiguo; Bai, Tao; Xu, Jianxiang; Cai, Jun; Barnes, Gregory; Liu, Qiu-Ju; Freedman, Jonathan H; Wang, Yonggang; Liu, Quan; Zheng, Yang; Cai, Lu

2017-06-01

Obesity often leads to obesity-related cardiac hypertrophy (ORCH), which is suppressed by zinc-induced inactivation of p38 mitogen-activated protein kinase (p38 MAPK). In this study, we investigated the mechanisms by which zinc inactivates p38 MAPK to prevent ORCH. Mice (4-week old) were fed either high fat diet (HFD, 60% kcal fat) or normal diet (ND, 10% kcal fat) containing variable amounts of zinc (deficiency, normal and supplement) for 3 and 6 months. P38 MAPK siRNA and the p38 MAPK inhibitor SB203580 were used to suppress p38 MAPK activity in vitro and in vivo, respectively. HFD activated p38 MAPK and increased expression of B-cell lymphoma/CLL 10 (BCL10) and caspase recruitment domain family member 9 (CARD9). These responses were enhanced by zinc deficiency and attenuated by zinc supplement. Administration of SB203580 to HFD mice or specific siRNA in palmitate-treated cardiomyocytes eliminated the HFD and zinc deficiency activation of p38 MAPK, but did not significantly impact the expression of BCL10 and CARD9. In cultured cardiomyocytes, inhibition of BCL10 expression by siRNA prevented palmitate-induced increased p38 MAPK activation and atrial natriuretic peptide (ANP) expression. In contrast, inhibition of p38 MAPK prevented ANP expression, but did not affect BCL10 expression. Deletion of metallothionein abolished the protective effect of zinc on palmitate-induced up-regulation of BCL10 and phospho-p38 MAPK. HFD and zinc deficiency synergistically induce ORCH by increasing oxidative stress-mediated activation of BCL10/CARD9/p38 MAPK signalling. Zinc supplement ameliorates ORCH through activation of metallothionein to repress oxidative stress-activated BCL10 expression and p38 MAPK activation. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

PDV2 has a dosage effect on chloroplast division in Arabidopsis.

PubMed

Chang, Ning; Sun, Qingqing; Li, Yiqiong; Mu, Yajuan; Hu, Jinglei; Feng, Yue; Liu, Xiaomin; Gao, Hongbo

2017-03-01

PDV2 has a dosage effect on chloroplast division in Arabidopsis thaliana , but this effect may vary in different plants. Chloroplasts have to be divided as plants grow to maintain an optimized number in the cell. Chloroplasts are divided by protein complexes across the double membranes from the stroma side to the cytosolic side. PDV2 is a chloroplast division protein on the chloroplast outer membrane. It recruits the dynamin-related GTPase ARC5 to the division site. The C-terminus of PDV2 and the C-terminus of ARC6 interact in the intermembrane space, which is important for the localization of PDV2. Previously, it was shown that overexpression of PDV2 can increase the division of chloroplasts in Arabidopsis and moss, so the authors concluded that PDV2 determines the rate of chloroplast division in land plants. PDV2 was also shown to inhibit the GTPase activity of ARC5 by in vitro experiment. These results look to be contradictory. Here, we identified a null allele of PDV2 in Arabidopsis and studied plants with different levels of PDV2. Our results suggested that the chloroplast division phenotype in Arabidopsis is sensitive to the level of PDV2, while this is not the case for ARC6. The level of PDV2 protein is reduced sharply in fast-growing leaves, while the level of ARC6 is not. The levels of PDV2 and ARC6 in several other plant species at different developmental stages were also investigated. The results indicated that their expression pattern varies in different species. Thus, PDV2 is an important positive factor of chloroplast division with an apparent dosage effect in Arabidopsis, but this effect for different chloroplast division proteins in different plants may vary.

The role of metallothioneins, selenium and transfer to offspring in mercury detoxification in Franciscana dolphins (Pontoporia blainvillei).

PubMed

Romero, M B; Polizzi, P; Chiodi, L; Das, K; Gerpe, M

2016-08-15

The concentrations of mercury (Hg), selenium (Se) and metallothioneins (MT) were evaluated in fetuses, calves, juveniles and adults of the endangered coastal Franciscana dolphin (Pontoporia blainvillei) from Argentina. Mercury concentrations varied among analyzed tissues (liver, kidney, muscle and brain), with liver showing the higher concentrations in all specimens. An age-dependent accumulation was found in liver, kidney and brain. No significant relationship between Hg and MT concentrations was found for all tissues analyzed. Hepatic Hg molar concentrations were positively correlated with those of Se, indicating a great affinity between these two elements. Furthermore, dark granules of HgSe were observed in Kupffer cells in the liver by electron microscopy, suggesting the role of this macrophage in the detoxification of Hg. A transfer of Hg through placenta was proved. The presence of Hg in brain in all age classes did not show concentrations associated with neurotoxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

In Planta Response of Arabidopsis to Photothermal Impact Mediated by Gold Nanoparticles.

PubMed

Koo, Yeonjong; Lukianova-Hleb, Ekaterina Y; Pan, Joann; Thompson, Sean M; Lapotko, Dmitri O; Braam, Janet

2016-02-03

Biological responses to photothermal effects of gold nanoparticles (GNPs) have been demonstrated and employed for various applications in diverse systems except for one important class - plants. Here, the uptake of GNPs through Arabidopsis thaliana roots and translocation to leaves are reported. Successful plasmonic nanobubble generation and acoustic signal detection in planta is demonstrated. Furthermore, Arabidopsis leaves harboring GNPs and exposed to continuous laser or noncoherent light show elevated temperatures across the leaf surface and induced expression of heat-shock regulated genes. Overall, these results demonstrate that Arabidopsis can readily take up GNPs through the roots and translocate the particles to leaf tissues. Once within leaves, GNPs can act as photothermal agents for on-demand remote activation of localized biological processes in plants. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reducing isozyme competition increases target fatty acid accumulation in seed triacylglycerols of transgenic Arabidopsis

USDA-ARS?s Scientific Manuscript database

One goal of green chemistry is the production of industrially useful fatty acids (FAs) in crop plants. We focus on the engineering of industrial FAs, specifically hydroxy fatty acids (HFA) and conjugated polyenoic fatty acids (a-eleostearic acid, ESA), using Arabidopsis (Arabidopsis thaliana) as a m...

Magnesium uptake characteristics in Arabidopsis revealed by 28Mg tracer studies.

PubMed

Ogura, Takaaki; Kobayashi, Natsuko I; Suzuki, Hisashi; Iwata, Ren; Nakanishi, Tomoko M; Tanoi, Keitaro

2018-06-07

The Mg 2+ uptake system in Arabidopsis roots is Gd 3+ - and Fe 2+ -sensitive, and responds to a changing Mg 2+ concentration within 1 h with the participation of AtMRS2 transporters. Magnesium (Mg 2+ ) absorption and the mechanism regulating its activity have not been clarified yet. To address these issues, it is necessary to reveal the characteristics of Mg 2+ uptake in roots. Therefore, we first investigated the Mg 2+ uptake characteristics in roots of 1-week-old Arabidopsis plants using 28 Mg. The Mg 2+ uptake system in roots was up-regulated within 1 h in response to the low Mg 2+ condition. This induction was inhibited in Arabidopsis "mitochondrial RNA splicing 2/magnesium transport" mutants atmrs2-4/atmgt6 and atmrs2-7/atmgt7, while the expression of AtMRS2-4/AtMGT6 and AtMRS2-7/AtMGT7 genes in the Arabidopsis wild-type was not responsive to Mg 2+ conditions. In addition, the Mg deficiency-induced Mg 2+ uptake system was shut-down within 5 min when Mg 2+ was resupplied to the environment. An inhibition study showed that the constitutive mechanism functioning in Mg 2+ uptake under Mg 2+ sufficient conditions was sensitive to a number of divalent and trivalent cations, particularly Gd 3+ and Fe 2+ , but not to K + .

Process development for a recombinant Chinese hamster ovary (CHO) cell line utilizing a metal induced and amplified metallothionein expression system.

PubMed

Huang, Edwin P; Marquis, Christopher P; Gray, Peter P

2004-11-20

The suspension Chinese Hamster Ovary cell line, 13-10-302, utilizing the metallothionein (MT) expression system producing recombinant human growth hormone (hGH) was studied in a serum-free and cadmium-free medium at different fermentation scales and modes of operation. Initial experiments were carried out to optimize the concentration of metal addition to induce the MT promoter. Subsequently, the cultivation of the 13-10-302 cell line was scaled up from spinner flasks into bioreactors, and the cultivation duration was extended with fed-batch and perfusion strategies utilizing 180 microM zinc to induce the promoter controlling expression of recombinant hGH. It was shown that a fed-batch process could increase the maximum cell numbers twofold, from 3.3 to 6.3 x 10(6) cell/mL, over those obtained in normal batch fermentations, and this coupled with extended fermentation times resulted in a fourfold increase in final hGH titer, from 135 +/- 15 to 670 +/- 70 mg/L at a specific productivity q(hGH) value of 12 pg cell(-1)d(-1). The addition of sodium butyrate increased the specific productivity of hGH in cells to a value of approximately 48 pg cell(-1)d(-1), resulting in a final hGH titer of over a gram per liter during fed-batch runs. A BioSep acoustic cell recycler was used to retain the cells in the bioreactor during perfusion operation. It was necessary to maintain the specific feeding rates (SFR) above a value of 0.2 vvd/(10(6) cell/mL) to maintain the viability and productivity of the 13-10-302 cells; under these conditions the viable cell number increased to over 10(7) cell/mL and resulted in a volumetric productivity of over 120 mg(hGH) L(-1)d(-1). Process development described in this work demonstrates cultivation at various scales and sustained high levels of productivity under cadmium free condition in a CHO cell line utilizing an inducible metallothionein expression system. (c) 2004 Wiley Periodicals, Inc

Cuticle ultrastructure, cuticular lipid composition, and gene expression in hypoxia-stressed Arabidopsis stems and leaves.

PubMed

Kim, Hyojin; Choi, Dongsu; Suh, Mi Chung

2017-06-01

An increased permeability of the cuticle is closely associated with downregulation of genes involved in cuticular lipid synthesis in hypoxia-stressed Arabidopsis and may allow plants to cope with oxygen deficiency. The hydrophobic cuticle layer consisting of cutin polyester and cuticular wax is the first barrier to protect the aerial parts of land plants from environmental stresses. In the present study, we investigated the role of cuticle membrane in Arabidopsis responses to oxygen deficiency. TEM analysis showed that the epidermal cells of hypoxia-treated Arabidopsis stems and leaves possessed a thinner electron-translucent cuticle proper and a more electron-dense cuticular layer. A reduction in epicuticular wax crystal deposition was observed in SEM images of hypoxia-treated Arabidopsis stem compared with normoxic control. Cuticular transpiration was more rapid in hypoxia-stressed leaves than in normoxic control. Total wax and cutin loads decreased by approximately 6-12 and 12-22%, respectively, and the levels of C29 alkanes, secondary alcohols, and ketones, C16:0 ω-hydroxy fatty acids, and C18:2 dicarboxylic acids were also prominently reduced in hypoxia-stressed Arabidopsis leaves and/or stems relative to normoxic control. Genome-wide transcriptome and quantitative RT-PCR analyses revealed that the expression of several genes involved in the biosynthesis and transport of cuticular waxes and cutin monomers were downregulated more than fourfold, but no significant alterations were detected in the transcript levels of fatty acid biosynthetic genes, BCCP2, PDH-E1α, and ENR1 in hypoxia-treated Arabidopsis stems and leaves compared with normoxic control. Taken together, an increased permeability of the cuticle is closely associated with downregulation of genes involved in cuticular lipid synthesis in hypoxia-stressed Arabidopsis. The present study elucidates one of the cuticle-related adaptive responses that may allow plants to cope with low oxygen levels.

Role of ARF6 in internalization of metal-binding proteins, metallothionein and transferrin, and cadmium-metallothionein toxicity in kidney proximal tubule cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolff, Natascha A.; Lee, Wing-Kee; Abouhamed, Marouan

2008-07-01

Filtered metal-protein complexes, such as cadmium-metallothionein-1 (CdMT-1) or transferrin (Tf) are apically endocytosed partly via megalin/cubilin by kidney proximal tubule (PT) cells where CdMT-1 internalization causes apoptosis. Small GTPase ARF (ADP-ribosylation factor) proteins regulate endocytosis and vesicular trafficking. We investigated roles of ARF6, which has been shown to be involved in internalization of ligands and endocytic trafficking in PT cells, following MT-1/CdMT-1 and Tf uptake by PT cells. WKPT-0293 Cl.2 cells derived from rat PT S1 segment were transfected with hemagglutinin-tagged wild-type (ARF6-WT) or dominant negative (ARF6-T27N) forms of ARF6. Using immunofluorescence, endogenous ARF6 was associated with the plasma membranemore » (PM) as well as juxtanuclear and co-localized with Rab5a and Rab11 involved in early and recycling endosomal trafficking. Immunofluorescence staining of megalin showed reduced surface labelling in ARF6 dominant negative (ARF6-DN) cells. Intracellular Alexa Fluor 546-conjugated MT-1 uptake was reduced in ARF6-DN cells and CdMT-1 (14.8 {mu}M for 24 h) toxicity was significantly attenuated from 27.3 {+-} 3.9% in ARF6-WT to 11.1 {+-} 4.0% in ARF6-DN cells (n = 6, P < 0.02). Moreover, reduced Alexa Fluor 546-conjugated Tf uptake was observed in ARF-DN cells (75.0 {+-} 4.6% versus 3.9 {+-} 3.9% of ARF6-WT cells, n = 3, P < 0.01) and/or remained near the PM (89.3 {+-} 5. 6% versus 45.2 {+-} 14.3% of ARF6-WT cells, n = 3, P < 0.05). In conclusion, the data support roles for ARF6 in receptor-mediated endocytosis and trafficking of MT-1/Tf to endosomes/lysosomes and CdMT-1 toxicity of PT cells.« less

Engineering calcium oxalate crystal formation in Arabidopsis

USDA-ARS?s Scientific Manuscript database

Many plants accumulate crystals of calcium oxalate. Just how these crystals form remains unknown. To gain insight into the mechanisms regulating calcium oxalate crystal formation, a crystal engineering approach was initiated utilizing the non-crystal accumulating plant, Arabidopsis. The success of t...

Developmentally distinct MYB genes encode functionally equivalent proteins in Arabidopsis.

PubMed

Lee, M M; Schiefelbein, J

2001-05-01

The duplication and divergence of developmental control genes is thought to have driven morphological diversification during the evolution of multicellular organisms. To examine the molecular basis of this process, we analyzed the functional relationship between two paralogous MYB transcription factor genes, WEREWOLF (WER) and GLABROUS1 (GL1), in Arabidopsis. The WER and GL1 genes specify distinct cell types and exhibit non-overlapping expression patterns during Arabidopsis development. Nevertheless, reciprocal complementation experiments with a series of gene fusions showed that WER and GL1 encode functionally equivalent proteins, and their unique roles in plant development are entirely due to differences in their cis-regulatory sequences. Similar experiments with a distantly related MYB gene (MYB2) showed that its product cannot functionally substitute for WER or GL1. Furthermore, an analysis of the WER and GL1 proteins shows that conserved sequences correspond to specific functional domains. These results provide new insights into the evolution of the MYB gene family in Arabidopsis, and, more generally, they demonstrate that novel developmental gene function may arise solely by the modification of cis-regulatory sequences.

Rubisco small subunits from the unicellular green alga Chlamydomonas complement Rubisco-deficient mutants of Arabidopsis.

PubMed

Atkinson, Nicky; Leitão, Nuno; Orr, Douglas J; Meyer, Moritz T; Carmo-Silva, Elizabete; Griffiths, Howard; Smith, Alison M; McCormick, Alistair J

2017-04-01

Introducing components of algal carbon concentrating mechanisms (CCMs) into higher plant chloroplasts could increase photosynthetic productivity. A key component is the Rubisco-containing pyrenoid that is needed to minimise CO 2 retro-diffusion for CCM operating efficiency. Rubisco in Arabidopsis was re-engineered to incorporate sequence elements that are thought to be essential for recruitment of Rubisco to the pyrenoid, namely the algal Rubisco small subunit (SSU, encoded by rbcS) or only the surface-exposed algal SSU α-helices. Leaves of Arabidopsis rbcs mutants expressing 'pyrenoid-competent' chimeric Arabidopsis SSUs containing the SSU α-helices from Chlamydomonas reinhardtii can form hybrid Rubisco complexes with catalytic properties similar to those of native Rubisco, suggesting that the α-helices are catalytically neutral. The growth and photosynthetic performance of complemented Arabidopsis rbcs mutants producing near wild-type levels of the hybrid Rubisco were similar to those of wild-type controls. Arabidopsis rbcs mutants expressing a Chlamydomonas SSU differed from wild-type plants with respect to Rubisco catalysis, photosynthesis and growth. This confirms a role for the SSU in influencing Rubisco catalytic properties. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Metallothionein 2A affects the cell respiration by suppressing the expression of mitochondrial protein cytochrome c oxidase subunit II.

PubMed

Bragina, Olga; Gurjanova, Karina; Krishtal, Jekaterina; Kulp, Maria; Karro, Niina; Tõugu, Vello; Palumaa, Peep

2015-06-01

Metallothioneins (MT) are involved in a broad range of cellular processes and play a major role in protection of cells towards various stressors. Two functions of MTs, namely the maintaining of the homeostasis of transition metal ions and the redox balance, are directly linked to the functioning of mitochondria. Dyshomeostasis of MTs is often related with malfunctioning of mitochondria; however, the mechanism by which MTs affect the mitochondrial respiratory chain is still unknown. We demonstrated that overexpression of MT-2A in HEK cell line decreased the oxidative phosphorylation capacity of the cells. HEK cells overexpressing MT-2A demonstrated reduced oxygen consumption and lower cellular ATP levels. MT-2A did not affect the number of mitochondria, but reduced specifically the level of cytochrome c oxidase subunit II protein, which resulted in lower activity of the complex IV.

Genomic architecture of biomass heterosis in Arabidopsis.

PubMed

Yang, Mei; Wang, Xuncheng; Ren, Diqiu; Huang, Hao; Xu, Miqi; He, Guangming; Deng, Xing Wang

2017-07-25

Heterosis is most frequently manifested by the substantially increased vigorous growth of hybrids compared with their parents. Investigating genomic variations in natural populations is essential to understand the initial molecular mechanisms underlying heterosis in plants. Here, we characterized the genomic architecture associated with biomass heterosis in 200 Arabidopsis hybrids. The genome-wide heterozygosity of hybrids makes a limited contribution to biomass heterosis, and no locus shows an obvious overdominance effect in hybrids. However, the accumulation of significant genetic loci identified in genome-wide association studies (GWAS) in hybrids strongly correlates with better-parent heterosis (BPH). Candidate genes for biomass BPH fall into diverse biological functions, including cellular, metabolic, and developmental processes and stimulus-responsive pathways. Important heterosis candidates include WUSCHEL , ARGOS , and some genes that encode key factors involved in cell cycle regulation. Interestingly, transcriptomic analyses in representative Arabidopsis hybrid combinations reveal that heterosis candidate genes are functionally enriched in stimulus-responsive pathways, including responses to biotic and abiotic stimuli and immune responses. In addition, stimulus-responsive genes are repressed to low-parent levels in hybrids with high BPH, whereas middle-parent expression patterns are exhibited in hybrids with no BPH. Our study reveals a genomic architecture for understanding the molecular mechanisms of biomass heterosis in Arabidopsis , in which the accumulation of the superior alleles of genes involved in metabolic and cellular processes improve the development and growth of hybrids, whereas the overall repressed expression of stimulus-responsive genes prioritizes growth over responding to environmental stimuli in hybrids under normal conditions.

Sulfinylated Azadecalins act as functional mimics of a pollen germination stimulant in Arabidopsis pistils

PubMed Central

Qin, Yuan; Wysocki, Ronald J; Somogyi, Arpad; Feinstein, Yelena; Franco, Jessica Y; Tsukamoto, Tatsuya; Dunatunga, Damayanthi; Levy, Clara; Smith, Steven; Simpson, Robert; Gang, David; Johnson, Mark A; Palanivelu, Ravishankar

2011-01-01

SUMMARY Polarized cell elongation is triggered by small molecule cues during development of diverse organisms. During plant reproduction, pollen interactions with the stigma result in the polar outgrowth of a pollen tube, which delivers sperm cells to the female gametophyte to effect double fertilization. In many plants, pistils stimulate pollen germination. However, in Arabidopsis, the effect of pistils on pollen germination and the pistil factors that stimulate pollen germination remain poorly characterized. Here, we demonstrate that stigma, style, and ovules in Arabidopsis pistils stimulate pollen germination. We isolated an Arabidopsis pistil extract fraction that stimulates Arabidopsis pollen germination, and employed ultrahigh resolution ESI FT-ICR and MS/MS techniques to accurately determine the mass (202.126 daltons) of a compound that is specifically present in this pistil extract fraction. Using the molecular formula (C10H19NOS) and tandem mass spectral fragmentation patterns of the m/z (mass to charge ratio) 202.126 ion, we postulated chemical structures, devised protocols, synthesized N-Methanesulfinyl 1- and 2-azadecalins that are close structural mimics of the m/z 202.126 ion, and showed that they are sufficient to stimulate Arabidopsis pollen germination in vitro (30 µM stimulated ~50% germination) and elicit accession-specific response. Although N-Methanesulfinyl 2-azadecalin stimulated pollen germination in three species of Lineage I of Brassicaceae, it did not induce a germination response in Sisymbrium irio (Lineage II of Brassicaceae) and tobacco, indicating that activity of the compound is not random. Our results show that Arabidopsis pistils promote germination by producing azadecalin-like molecules to ensure rapid fertilization by the appropriate pollen. PMID:21801250

Overexpression of 20-Oxidase Confers a Gibberellin-Overproduction Phenotype in Arabidopsis

PubMed Central

Huang, Shihshieh; Raman, Anuradha S.; Ream, Joel E.; Fujiwara, Hideji; Cerny, R. Eric; Brown, Sherri M.

1998-01-01

In the gibberellin (GA) biosynthesis pathway, 20-oxidase catalyzes the oxidation and elimination of carbon-20 to give rise to C19-GAs. All bioactive GAs are C19-GAs. We have overexpressed a cDNA encoding 20-oxidase isolated from Arabidopsis seedlings in transgenic Arabidopsis plants. These transgenic plants display a phenotype that may be attributed to the overproduction of GA. The phenotype includes a longer hypocotyl, lighter-green leaves, increased stem elongation, earlier flowering, and decreased seed dormancy. However, the fertility of the transgenic plants is not affected. Increased levels of endogenous GA1, GA9, and GA20 were detected in seedlings of the transgenic line examined. GA4, which is thought to be the predominantly active GA in Arabidopsis, was not present at increased levels in this line. These results suggest that the overexpression of this 20-oxidase increases the levels of some endogenous GAs in transgenic seedlings, which causes the GA-overproduction phenotype. PMID:9808721

Great majority of recombination events in Arabidopsis are gene conversion events

PubMed Central

Yang, Sihai; Yuan, Yang; Wang, Long; Li, Jing; Wang, Wen; Liu, Haoxuan; Chen, Jian-Qun; Hurst, Laurence D.; Tian, Dacheng

2012-01-01

The evolutionary importance of meiosis may not solely be associated with allelic shuffling caused by crossing-over but also have to do with its more immediate effects such as gene conversion. Although estimates of the crossing-over rate are often well resolved, the gene conversion rate is much less clear. In Arabidopsis, for example, next-generation sequencing approaches suggest that the two rates are about the same, which contrasts with indirect measures, these suggesting an excess of gene conversion. Here, we provide analysis of this problem by sequencing 40 F2 Arabidopsis plants and their parents. Small gene conversion tracts, with biased gene conversion content, represent over 90% (probably nearer 99%) of all recombination events. The rate of alteration of protein sequence caused by gene conversion is over 600 times that caused by mutation. Finally, our analysis reveals recombination hot spots and unexpectedly high recombination rates near centromeres. This may be responsible for the previously unexplained pattern of high genetic diversity near Arabidopsis centromeres. PMID:23213238

Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana.

PubMed

Mayer, K; Schüller, C; Wambutt, R; Murphy, G; Volckaert, G; Pohl, T; Düsterhöft, A; Stiekema, W; Entian, K D; Terryn, N; Harris, B; Ansorge, W; Brandt, P; Grivell, L; Rieger, M; Weichselgartner, M; de Simone, V; Obermaier, B; Mache, R; Müller, M; Kreis, M; Delseny, M; Puigdomenech, P; Watson, M; Schmidtheini, T; Reichert, B; Portatelle, D; Perez-Alonso, M; Boutry, M; Bancroft, I; Vos, P; Hoheisel, J; Zimmermann, W; Wedler, H; Ridley, P; Langham, S A; McCullagh, B; Bilham, L; Robben, J; Van der Schueren, J; Grymonprez, B; Chuang, Y J; Vandenbussche, F; Braeken, M; Weltjens, I; Voet, M; Bastiaens, I; Aert, R; Defoor, E; Weitzenegger, T; Bothe, G; Ramsperger, U; Hilbert, H; Braun, M; Holzer, E; Brandt, A; Peters, S; van Staveren, M; Dirske, W; Mooijman, P; Klein Lankhorst, R; Rose, M; Hauf, J; Kötter, P; Berneiser, S; Hempel, S; Feldpausch, M; Lamberth, S; Van den Daele, H; De Keyser, A; Buysshaert, C; Gielen, J; Villarroel, R; De Clercq, R; Van Montagu, M; Rogers, J; Cronin, A; Quail, M; Bray-Allen, S; Clark, L; Doggett, J; Hall, S; Kay, M; Lennard, N; McLay, K; Mayes, R; Pettett, A; Rajandream, M A; Lyne, M; Benes, V; Rechmann, S; Borkova, D; Blöcker, H; Scharfe, M; Grimm, M; Löhnert, T H; Dose, S; de Haan, M; Maarse, A; Schäfer, M; Müller-Auer, S; Gabel, C; Fuchs, M; Fartmann, B; Granderath, K; Dauner, D; Herzl, A; Neumann, S; Argiriou, A; Vitale, D; Liguori, R; Piravandi, E; Massenet, O; Quigley, F; Clabauld, G; Mündlein, A; Felber, R; Schnabl, S; Hiller, R; Schmidt, W; Lecharny, A; Aubourg, S; Chefdor, F; Cooke, R; Berger, C; Montfort, A; Casacuberta, E; Gibbons, T; Weber, N; Vandenbol, M; Bargues, M; Terol, J; Torres, A; Perez-Perez, A; Purnelle, B; Bent, E; Johnson, S; Tacon, D; Jesse, T; Heijnen, L; Schwarz, S; Scholler, P; Heber, S; Francs, P; Bielke, C; Frishman, D; Haase, D; Lemcke, K; Mewes, H W; Stocker, S; Zaccaria, P; Bevan, M; Wilson, R K; de la Bastide, M; Habermann, K; Parnell, L; Dedhia, N; Gnoj, L; Schutz, K; Huang, E; Spiegel, L; Sehkon, M; Murray, J; Sheet, P; Cordes, M; Abu-Threideh, J; Stoneking, T; Kalicki, J; Graves, T; Harmon, G; Edwards, J; Latreille, P; Courtney, L; Cloud, J; Abbott, A; Scott, K; Johnson, D; Minx, P; Bentley, D; Fulton, B; Miller, N; Greco, T; Kemp, K; Kramer, J; Fulton, L; Mardis, E; Dante, M; Pepin, K; Hillier, L; Nelson, J; Spieth, J; Ryan, E; Andrews, S; Geisel, C; Layman, D; Du, H; Ali, J; Berghoff, A; Jones, K; Drone, K; Cotton, M; Joshu, C; Antonoiu, B; Zidanic, M; Strong, C; Sun, H; Lamar, B; Yordan, C; Ma, P; Zhong, J; Preston, R; Vil, D; Shekher, M; Matero, A; Shah, R; Swaby, I K; O'Shaughnessy, A; Rodriguez, M; Hoffmann, J; Till, S; Granat, S; Shohdy, N; Hasegawa, A; Hameed, A; Lodhi, M; Johnson, A; Chen, E; Marra, M; Martienssen, R; McCombie, W R

1999-12-16

The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

The metallothionein gene from the white shrimp Litopenaeus vannamei: characterization and expression in response to hypoxia.

PubMed

Felix-Portillo, Monserrath; Martinez-Quintana, José A; Peregrino-Uriarte, Alma B; Yepiz-Plascencia, Gloria

2014-10-01

Aquatic animals encounter variation in oxygen tension that leads to the accumulation of reactive oxygen species (ROS) that can harm the organisms. Under these circumstances some organisms have evolved to tolerate hypoxia. In mammals, metallothioneins (MTs) protect against hypoxia-generated ROS. Here we report the MT gene from the shrimp Litopenaeus vannamei (LvMT). LvMT is differentially expressed in hemocytes, intestine, gills, pleopods, heart, hepatopancreas and muscle, with the highest levels in hepatopancreas and heart. LvMT mRNA increases during hypoxia in hepatopancreas and gills after 3 h at 1.5 mg L(-1) dissolved oxygen (DO). This gene structure resembles the homologs from invertebrates and vertebrates possessing three exons, two introns and response elements for metal response transcription factor 1 (MTF-1), hypoxia-inducible factor 1 (HIF-1) and p53 in the promoter region. During hypoxia, HIF-1/MTF-1 might participate inducing MT to contribute towards the tolerance to ROS toxicity. MT importance in aquatic organisms may include also ROS-detoxifying processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Arabidopsis SEIPIN Proteins Modulate Triacylglycerol Accumulation and Influence Lipid Droplet Proliferation[OPEN

PubMed Central

2015-01-01

The lipodystrophy protein SEIPIN is important for lipid droplet (LD) biogenesis in human and yeast cells. In contrast with the single SEIPIN genes in humans and yeast, there are three SEIPIN homologs in Arabidopsis thaliana, designated SEIPIN1, SEIPIN2, and SEIPIN3. Essentially nothing is known about the functions of SEIPIN homologs in plants. Here, a yeast (Saccharomyces cerevisiae) SEIPIN deletion mutant strain and a plant (Nicotiana benthamiana) transient expression system were used to test the ability of Arabidopsis SEIPINs to influence LD morphology. In both species, expression of SEIPIN1 promoted accumulation of large-sized lipid droplets, while expression of SEIPIN2 and especially SEIPIN3 promoted small LDs. Arabidopsis SEIPINs increased triacylglycerol levels and altered composition. In tobacco, endoplasmic reticulum (ER)-localized SEIPINs reorganized the normal, reticulated ER structure into discrete ER domains that colocalized with LDs. N-terminal deletions and swapping experiments of SEIPIN1 and 3 revealed that this region of SEIPIN determines LD size. Ectopic overexpression of SEIPIN1 in Arabidopsis resulted in increased numbers of large LDs in leaves, as well as in seeds, and increased seed oil content by up to 10% over wild-type seeds. By contrast, RNAi suppression of SEIPIN1 resulted in smaller seeds and, as a consequence, a reduction in the amount of oil per seed compared with the wild type. Overall, our results indicate that Arabidopsis SEIPINs are part of a conserved LD biogenesis machinery in eukaryotes and that in plants these proteins may have evolved specialized roles in the storage of neutral lipids by differentially modulating the number and sizes of lipid droplets. PMID:26362606

MIPS Arabidopsis thaliana Database (MAtDB): an integrated biological knowledge resource based on the first complete plant genome

PubMed Central

Schoof, Heiko; Zaccaria, Paolo; Gundlach, Heidrun; Lemcke, Kai; Rudd, Stephen; Kolesov, Grigory; Arnold, Roland; Mewes, H. W.; Mayer, Klaus F. X.

2002-01-01

Arabidopsis thaliana is the first plant for which the complete genome has been sequenced and published. Annotation of complex eukaryotic genomes requires more than the assignment of genetic elements to the sequence. Besides completing the list of genes, we need to discover their cellular roles, their regulation and their interactions in order to understand the workings of the whole plant. The MIPS Arabidopsis thaliana Database (MAtDB; http://mips.gsf.de/proj/thal/db) started out as a repository for genome sequence data in the European Scientists Sequencing Arabidopsis (ESSA) project and the Arabidopsis Genome Initiative. Our aim is to transform MAtDB into an integrated biological knowledge resource by integrating diverse data, tools, query and visualization capabilities and by creating a comprehensive resource for Arabidopsis as a reference model for other species, including crop plants. PMID:11752263

Gibberellic Acid-Stimulated Arabidopsis6 Serves as an Integrator of Gibberellin, Abscisic Acid, and Glucose Signaling during Seed Germination in Arabidopsis1[OPEN

PubMed Central

Zhong, Chunmei; Xu, Hao; Ye, Siting; Wang, Shiyi; Li, Lingfei; Zhang, Shengchun; Wang, Xiaojing

2015-01-01

The DELLA protein REPRESSOR OF ga1-3-LIKE2 (RGL2) plays an important role in seed germination under different conditions through a number of transcription factors. However, the functions of the structural genes associated with RGL2-regulated germination are less defined. Here, we report the role of an Arabidopsis (Arabidopsis thaliana) cell wall-localized protein, Gibberellic Acid-Stimulated Arabidopsis6 (AtGASA6), in functionally linking RGL2 and a cell wall loosening expansin protein (Arabidopsis expansin A1 [AtEXPA1]), resulting in the control of embryonic axis elongation and seed germination. AtGASA6-overexpressing seeds showed precocious germination, whereas transfer DNA and RNA interference mutant seeds displayed delayed seed germination under abscisic acid, paclobutrazol, and glucose (Glc) stress conditions. The differences in germination rates resulted from corresponding variation in cell elongation in the hypocotyl-radicle transition region of the embryonic axis. AtGASA6 was down-regulated by RGL2, GLUCOSE INSENSITIVE2, and ABSCISIC ACID-INSENSITIVE5 genes, and loss of AtGASA6 expression in the gasa6 mutant reversed the insensitivity shown by the rgl2 mutant to paclobutrazol and the gin2 mutant to Glc-induced stress, suggesting that it is involved in regulating both the gibberellin and Glc signaling pathways. Furthermore, it was found that the promotion of seed germination and length of embryonic axis by AtGASA6 resulted from a promotion of cell elongation at the embryonic axis mediated by AtEXPA1. Taken together, the data indicate that AtGASA6 links RGL2 and AtEXPA1 functions and plays a role as an integrator of gibberellin, abscisic acid, and Glc signaling, resulting in the regulation of seed germination through a promotion of cell elongation. PMID:26400990

Shark (Scyliorhinus torazame) metallothionein: cDNA cloning, genomic sequence, and expression analysis.

PubMed

Cho, Young Sun; Choi, Buyl Nim; Ha, En-Mi; Kim, Ki Hong; Kim, Sung Koo; Kim, Dong Soo; Nam, Yoon Kwon

2005-01-01

Novel metallothionein (MT) complementary DNA and genomic sequences were isolated from a cartilaginous shark species, Scyliorhinus torazame. The full-length open reading frame (ORF) of shark MT cDNA encoded 68 amino acids with a high cysteine content (29%). The genomic ORF sequence (932 bp) of shark MT isolated by polymerase chain reaction (PCR) comprised 3 exons with 2 interventing introns. Shark MT sequence shared many conserved features with other vertebrate MTs: overall amino acid identities of shark MT ranged from 47% to 57% with fish MTs, and 41% to 62% with mammalian MTs. However, in addition to these conserved characteristics, shark MT sequence exhibited some unique characteristics. It contained 4 extra amino acids (Lys-Ala-Gly-Arg) at the end of the beta-domain, which have not been reported in any other vertebrate MTs. The last amino acid residue at the C-terminus was Ser, which also has not been reported in fish and mammalian MTs. The MT messenger RNA levels in shark liver and kidney, assessed by semiquantitative reverse transcriptase PCR and RNA blot hybridization, were significantly affected by experimental exposures to heavy metals (cadmium, copper, and zinc). Generally, the transcriptional activation of shark MT gene was dependent on the dose (0-10 mg/kg body weight for injection and 0-20 microM for immersion) and duration (1-10 days); zinc was a more potent inducer than copper and cadmium.

A hydroxycinnamoyltransferase responsible for synthesizing suberin aromatics in Arabidopsis

PubMed Central

Gou, Jin-Ying; Yu, Xiao-Hong; Liu, Chang-Jun

2009-01-01

Suberin, a polyester polymer in the cell wall of terrestrial plants, controls the transport of water and nutrients and protects plant from pathogenic infections and environmental stresses. Structurally, suberin consists of aliphatic and aromatic domains; p-hydroxycinnamates, such as ferulate, p-coumarate, and/or sinapate, are the major phenolic constituents of the latter. By analyzing the “wall-bound” phenolics of mutant lines of Arabidopsis deficient in a family of acyl-CoA dependent acyltransferase (BAHD) genes, we discovered that the formation of aromatic suberin in Arabidopsis, primarily in seed and root tissues, depends on a member of the BAHD superfamily of enzymes encoded by At5g41040. This enzyme exhibits an ω-hydroxyacid hydroxycinnamoyltransferase activity with an in vitro kinetic preference for feruloyl-CoA and 16-hydroxypalmitic acid. Knocking down or knocking out the At5g41040 gene in Arabidopsis reduces specifically the quantity of ferulate in suberin, but does not affect the accumulation of p-coumarate or sinapate. The loss of the suberin phenolic differentially affects the aliphatic monomer loads and alters the permeability and sensitivity of seeds and roots to salt stress. This highlights the importance of suberin aromatics in the polymer's function. PMID:19846769

Expansion of the receptor-like kinase/Pelle gene family and receptor-like proteins in Arabidopsis.

PubMed

Shiu, Shin Han; Bleecker, Anthony B

2003-06-01

Receptor-like kinases (RLKs) are a family of transmembrane proteins with versatile N-terminal extracellular domains and C-terminal intracellular kinases. They control a wide range of physiological responses in plants and belong to one of the largest gene families in the Arabidopsis genome with more than 600 members. Interestingly, this gene family constitutes 60% of all kinases in Arabidopsis and accounts for nearly all transmembrane kinases in Arabidopsis. Analysis of four fungal, six metazoan, and two Plasmodium sp. genomes indicates that the family was represented in all but fungal genomes, indicating an ancient origin for the family with a more recent expansion only in the plant lineages. The RLK/Pelle family can be divided into several subfamilies based on three independent criteria: the phylogeny based on kinase domain sequences, the extracellular domain identities, and intron locations and phases. A large number of receptor-like proteins (RLPs) resembling the extracellular domains of RLKs are also found in the Arabidopsis genome. However, not all RLK subfamilies have corresponding RLPs. Several RLK/Pelle subfamilies have undergone differential expansions. More than 33% of the RLK/Pelle members are found in tandem clusters, substantially higher than the genome average. In addition, 470 of the RLK/Pelle family members are located within the segmentally duplicated regions in the Arabidopsis genome and 268 of them have a close relative in the corresponding regions. Therefore, tandem duplications and segmental/whole-genome duplications represent two of the major mechanisms for the expansion of the RLK/Pelle family in Arabidopsis.

Survival, growth, metallothionein and glycogen levels of Nucella lapillus (L.) exposed to subchronic cadmium stress: the influence of nutritional state and prey type.

PubMed

Leung, K M; Furness, R W

2001-08-01

Dogwhelks Nucella lapillus feed mainly on mussels and barnacles, and may experience periods of starvation. We report effects of nutritional state and prey type on the survival, growth, cadmium (Cd) accumulation, metallothionein (MT) induction and glycogen stores in N. lapillus exposed to Cd in water. Adult dogwhelks, with similar shell length (30.0+/-1.5 mm), were either starved or fed to satiation with barnacles Semibalanus balanoides, mussels Mytilus edulis or Cd-dosed M. edulis, and kept in filtered natural seawater (< 0.01 microg Cd 1(-1)) or Cd-contaminated (400 microg Cd 1(-1)) seawater for 80 days. Mortality and individual growth rate were determined. Cd, MT and glycogen were measured in different tissues. Prolonged starvation and exposure to Cd significantly reduced the survivorship of N. lapillus, but feeding could help dogwhelks to combat Cd toxicity and minimise mortality. Extended starvation also caused tissue wastage, leading to higher concentrations of Cd and MT in tissues, whereas fed animals increased in weight and had lower Cd and MT concentrations because of the tissue dilution effect. Prey type significantly affected growth rate of dogwhelks and indirectly influenced Cd accumulation, MT induction and glycogen stores. Eating mussels promoted better growth and higher glycogen reserves than eating barnacles. Individual growth rate decreased with increasing Cd accumulation. Cd-exposed survivors grew faster and consumed more than control animals, implying that these survivors may have better fitness and greater tolerance to Cd toxicity. The use of growth, condition index, MT and glycogen as biomarkers of environmental pollution are discussed. These results indicate a need to incorporate biological data including growth (or at least condition index) and prey type into biomonitoring programmes to allow sound interpretation.

Genetic improvement of butanol tolerance in Escherichia coli by cell surface expression of fish metallothionein.

PubMed

Lin, Kuo Hsing; Chin, Wei Chih; Lee, Ang Hsuan; Huang, Chieh Chen

2011-01-01

Cysteine-rich metallothioneins (MTs) have been reported to possess the capacity to scavenge reactive oxygen species in vitro and in vivo. Recombinant strains of Escherichia coli expressing outer membrane protein C (OmpC) fused with MTs from human, mouse and tilapia displayed the ability for such surface-localized MTs to scavenge extracellular free radicals, but the benefits of the possible applications of this capacity have not yet been demonstrated. Because the intrinsic butanol tolerance of microbes has become an impediment for biological butanol production, we examined whether surface-displayed MTs could contribute to butanol tolerance. The results show that strains expressing OmpC-MT fusion proteins had higher butanol tolerance than strains with cytoplasmically expressed MTs. Furthermore, the OmpC-tilapia MT fusion protein enhanced butanol tolerance more strongly than other recombinant constructs. Although the enhanced level of tolerance was not as high as that provided by OmpC-tilapia MT, over-expression of OmpC was also found to contribute to butanol tolerance. These results suggest that free-radical scavenging by MT and OmpC-related osmoregulation enhance butanol tolerance. Our results shed new light on methods for engineering bacteria with higher butanol tolerance. © 2011 Landes Bioscience

Arabidopsis Hormone Database: a comprehensive genetic and phenotypic information database for plant hormone research in Arabidopsis

PubMed Central

Peng, Zhi-yu; Zhou, Xin; Li, Linchuan; Yu, Xiangchun; Li, Hongjiang; Jiang, Zhiqiang; Cao, Guangyu; Bai, Mingyi; Wang, Xingchun; Jiang, Caifu; Lu, Haibin; Hou, Xianhui; Qu, Lijia; Wang, Zhiyong; Zuo, Jianru; Fu, Xiangdong; Su, Zhen; Li, Songgang; Guo, Hongwei

2009-01-01

Plant hormones are small organic molecules that influence almost every aspect of plant growth and development. Genetic and molecular studies have revealed a large number of genes that are involved in responses to numerous plant hormones, including auxin, gibberellin, cytokinin, abscisic acid, ethylene, jasmonic acid, salicylic acid, and brassinosteroid. Here, we develop an Arabidopsis hormone database, which aims to provide a systematic and comprehensive view of genes participating in plant hormonal regulation, as well as morphological phenotypes controlled by plant hormones. Based on data from mutant studies, transgenic analysis and gene ontology (GO) annotation, we have identified a total of 1026 genes in the Arabidopsis genome that participate in plant hormone functions. Meanwhile, a phenotype ontology is developed to precisely describe myriad hormone-regulated morphological processes with standardized vocabularies. A web interface (http://ahd.cbi.pku.edu.cn) would allow users to quickly get access to information about these hormone-related genes, including sequences, functional category, mutant information, phenotypic description, microarray data and linked publications. Several applications of this database in studying plant hormonal regulation and hormone cross-talk will be presented and discussed. PMID:19015126

Arabidopsis Hormone Database: a comprehensive genetic and phenotypic information database for plant hormone research in Arabidopsis.

PubMed

Peng, Zhi-yu; Zhou, Xin; Li, Linchuan; Yu, Xiangchun; Li, Hongjiang; Jiang, Zhiqiang; Cao, Guangyu; Bai, Mingyi; Wang, Xingchun; Jiang, Caifu; Lu, Haibin; Hou, Xianhui; Qu, Lijia; Wang, Zhiyong; Zuo, Jianru; Fu, Xiangdong; Su, Zhen; Li, Songgang; Guo, Hongwei

2009-01-01

Plant hormones are small organic molecules that influence almost every aspect of plant growth and development. Genetic and molecular studies have revealed a large number of genes that are involved in responses to numerous plant hormones, including auxin, gibberellin, cytokinin, abscisic acid, ethylene, jasmonic acid, salicylic acid, and brassinosteroid. Here, we develop an Arabidopsis hormone database, which aims to provide a systematic and comprehensive view of genes participating in plant hormonal regulation, as well as morphological phenotypes controlled by plant hormones. Based on data from mutant studies, transgenic analysis and gene ontology (GO) annotation, we have identified a total of 1026 genes in the Arabidopsis genome that participate in plant hormone functions. Meanwhile, a phenotype ontology is developed to precisely describe myriad hormone-regulated morphological processes with standardized vocabularies. A web interface (http://ahd.cbi.pku.edu.cn) would allow users to quickly get access to information about these hormone-related genes, including sequences, functional category, mutant information, phenotypic description, microarray data and linked publications. Several applications of this database in studying plant hormonal regulation and hormone cross-talk will be presented and discussed.

Physiological Analysis of Phototropic Responses in Arabidopsis.

PubMed

Zeidler, Mathias

2016-01-01

Plants utilize light as sole energy source. To maximize light capture they are able to detect the light direction and orient themselves towards the light source. This phototropic response is mediated by the plant blue light photoreceptors phototropin1 and 2 (phot1 and phot2). Although fully differentiated plants also exhibit this response it can be best observed in etiolated seedlings. Differences in light between the illuminated and shaded site of a seedling stem lead to changes in the auxin-distribution, resulting in cell elongation on the shaded site. Since phototropism connects light perception, signaling, and auxin transport, it is of great interest to analyze this response with a fast and simple method.Here we describe a method to analyze the phototropic response of Arabidopsis seedlings. With numerous mutants available, its fast germination and its small size Arabidopsis is well suited for this analysis. Different genotypes can be simultaneously probed in less than a week.

DYn-2 Based Identification of Arabidopsis Sulfenomes*

PubMed Central

Akter, Salma; Huang, Jingjing; Bodra, Nandita; De Smet, Barbara; Wahni, Khadija; Rombaut, Debbie; Pauwels, Jarne; Gevaert, Kris; Carroll, Kate; Van Breusegem, Frank; Messens, Joris

2015-01-01

Identifying the sulfenylation state of stressed cells is emerging as a strategic approach for the detection of key reactive oxygen species signaling proteins. Here, we optimized an in vivo trapping method for cysteine sulfenic acids in hydrogen peroxide (H2O2) stressed plant cells using a dimedone based DYn-2 probe. We demonstrated that DYn-2 specifically detects sulfenylation events in an H2O2 dose- and time-dependent way. With mass spectrometry, we identified 226 sulfenylated proteins after H2O2 treatment of Arabidopsis cells, residing in the cytoplasm (123); plastid (68); mitochondria (14); nucleus (10); endoplasmic reticulum, Golgi and plasma membrane (7) and peroxisomes (4). Of these, 123 sulfenylated proteins have never been reported before to undergo cysteine oxidative post-translational modifications in plants. All in all, with this DYn-2 approach, we have identified new sulfenylated proteins, and gave a first glance on the locations of the sulfenomes of Arabidopsis thaliana. PMID:25693797

Impact of intracellular metallothionein on metal biouptake and partitioning dynamics at bacterial interfaces.

PubMed

Présent, Romain M; Rotureau, Elise; Billard, Patrick; Pagnout, Christophe; Sohm, Bénédicte; Flayac, Justine; Gley, Renaud; Pinheiro, José P; Duval, Jérôme F L

2017-11-08

Genetically engineered microorganisms are alternatives to physicochemical methods for remediation of metal-contaminated aquifers due to their remarkable bioaccumulation capacities. The design of such biosystems would benefit from the elaboration of a sound quantitative connection between performance in terms of metal removal from aqueous solution and dynamics of the multiscale processes leading to metal biouptake. In this work, this elaboration is reported for Escherichia coli cells modified to overexpress intracellular metallothionein (MTc), a strong proteinaceous metal chelator. Depletion kinetics of Cd(ii) from bulk solution following biouptake and intracellular accumulation is addressed as a function of cell volume fraction using electroanalytical probes and ligand exchange-based analyses. It is shown that metal biouptake in the absence and presence of MTc is successfully interpreted on the basis of a formalism recently developed for metal partitioning dynamics at biointerfaces with integration of intracellular metal speciation. The analysis demonstrates how fast sequestration of metals by intracellular MTc bypasses metal excretion (efflux) and enhances the rate of metal depletion to an extent such that complete removal is achieved at sufficiently large cell volume fractions. The magnitude of the stability constant of nanoparticulate metal-MTc complexes, as derived from refined analysis of macroscopic bulk metal depletion data, is further confirmed by independent electrochemical measurement of metal binding by purified MTc extracts.

Functional conservation of the yeast and Arabidopsis RAD54-like genes.

PubMed

Klutstein, Michael; Shaked, Hezi; Sherman, Amir; Avivi-Ragolsky, Naomi; Shema, Efrat; Zenvirth, Drora; Levy, Avraham A; Simchen, Giora

2008-04-01

The Saccharomyces cerevisiae RAD54 gene has critical roles in DNA double-strand break repair, homologous recombination, and gene targeting. Previous results show that the yeast gene enhances gene targeting when expressed in Arabidopsis thaliana. In this work we address the trans-species compatibility of Rad54 functions. We show that overexpression of yeast RAD54 in Arabidopsis enhances DNA damage resistance severalfold. Thus, the yeast gene is active in the Arabidopsis homologous-recombination repair system. Moreover, we have identified an A. thaliana ortholog of yeast RAD54, named AtRAD54. This gene, with close sequence similarity to RAD54, complements methylmethane sulfonate (MMS) sensitivity but not UV sensitivity or gene targeting defects of rad54Delta mutant yeast cells. Overexpression of AtRAD54 in Arabidopsis leads to enhanced resistance to DNA damage. This gene's assignment as a RAD54 ortholog is further supported by the interaction of AtRad54 with AtRad51 and the interactions between alien proteins (i.e., yeast Rad54 with AtRAD51 and yeast Rad51 with AtRad54) in a yeast two-hybrid experiment. These interactions hint at the molecular nature of this interkingdom complementation, although the stronger effect of the yeast Rad54 in plants than AtRad54 in yeast might be explained by an ability of the Rad54 protein to act alone, independently of its interaction with Rad51.

Partial Shotgun Sequencing of the Boechera stricta Genome Reveals Extensive Microsynteny and Promoter Conservation with Arabidopsis1[W

PubMed Central

Windsor, Aaron J.; Schranz, M. Eric; Formanová, Nataša; Gebauer-Jung, Steffi; Bishop, John G.; Schnabelrauch, Domenica; Kroymann, Juergen; Mitchell-Olds, Thomas

2006-01-01

Comparative genomics provides insight into the evolutionary dynamics that shape discrete sequences as well as whole genomes. To advance comparative genomics within the Brassicaceae, we have end sequenced 23,136 medium-sized insert clones from Boechera stricta, a wild relative of Arabidopsis (Arabidopsis thaliana). A significant proportion of these sequences, 18,797, are nonredundant and display highly significant similarity (BLASTn e-value ≤ 10−30) to low copy number Arabidopsis genomic regions, including more than 9,000 annotated coding sequences. We have used this dataset to identify orthologous gene pairs in the two species and to perform a global comparison of DNA regions 5′ to annotated coding regions. On average, the 500 nucleotides upstream to coding sequences display 71.4% identity between the two species. In a similar analysis, 61.4% identity was observed between 5′ noncoding sequences of Brassica oleracea and Arabidopsis, indicating that regulatory regions are not as diverged among these lineages as previously anticipated. By mapping the B. stricta end sequences onto the Arabidopsis genome, we have identified nearly 2,000 conserved blocks of microsynteny (bracketing 26% of the Arabidopsis genome). A comparison of fully sequenced B. stricta inserts to their homologous Arabidopsis genomic regions indicates that indel polymorphisms >5 kb contribute substantially to the genome size difference observed between the two species. Further, we demonstrate that microsynteny inferred from end-sequence data can be applied to the rapid identification and cloning of genomic regions of interest from nonmodel species. These results suggest that among diploid relatives of Arabidopsis, small- to medium-scale shotgun sequencing approaches can provide rapid and cost-effective benefits to evolutionary and/or functional comparative genomic frameworks. PMID:16607030

Melatonin as a signal molecule triggering defense responses against pathogen attack in Arabidopsis and tobacco.

PubMed

Lee, Hyoung Yool; Byeon, Yeong; Back, Kyoungwhan

2014-10-01

Melatonin plays pleiotropic roles in both animals and plants. The possible role of melatonin in plant innate immune responses was recently discovered. As an initial study, we employed Arabidopsis to determine whether melatonin is involved in defense against the virulent bacterial pathogen Pseudomonas syringae DC3000. The application of a 10 μM concentration of melatonin on Arabidopsis and tobacco leaves induced various pathogenesis-related (PR) genes, as well as a series of defense genes activated by salicylic acid (SA) and ethylene (ET), two key factors involved in plant defense response, compared to mock-treated leaves. The induction of these defense-related genes in melatonin-treated Arabidopsis matched an increase in resistance against the bacterium by suppressing its multiplication about ten-fold relative to the mock-treated Arabidopsis. Like melatonin, N-acetylserotonin also plays a role in inducing a series of defense genes, although serotonin does not. Furthermore, melatonin-induced PR genes were almost completely or partially suppressed in the npr1, ein2, and mpk6 Arabidopsis mutants, indicative of SA and ET dependency in melatonin-induced plant defense signaling. This suggests that melatonin may be a novel defense signaling molecule in plant-pathogen interactions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The mitochondrial electron transfer flavoprotein complex is essential for survival of Arabidopsis in extended darkness.

PubMed

Ishizaki, Kimitsune; Schauer, Nicolas; Larson, Tony R; Graham, Ian A; Fernie, Alisdair R; Leaver, Christopher J

2006-09-01

In mammals, the electron transfer flavoprotein (ETF) is a heterodimeric protein composed of two subunits, alpha and beta, that is responsible for the oxidation of at least nine mitochondrial matrix flavoprotein dehydrogenases. Electrons accepted by ETF are further transferred to the main respiratory chain via the ETF ubiquinone oxide reductase (ETFQO). Sequence analysis of the unique Arabidopsis homologues of two subunits of ETF revealed their high similarity to both subunits of the mammalian ETF. Yeast two-hybrid experiments showed that the Arabidopsis ETFalpha and ETFbeta can form a heteromeric protein. Isolation and characterization of two independent T-DNA insertional Arabidopsis mutants of the ETFbeta gene revealed accelerated senescence and early death compared to wild-type during extended darkness. Furthermore in contrast to wild-type, the etfb mutants demonstrated a significant accumulation of several amino acids, isovaleryl CoA and phytanoyl CoA during dark-induced carbohydrate deprivation. These phenotypic characteristics of etfb mutants are broadly similar to those that we observed previously in Arabidopsis etfqo mutants, suggesting functional association between ETF and ETFQO in Arabidopsis, and confirming the essential roles of the ETF/ETFQO electron transfer complex in the catabolism of leucine and involvement in the chlorophyll degradation pathway activated during dark-induced carbohydrate deprivation.

Metallothionein-3 Increases Triple-Negative Breast Cancer Cell Invasiveness via Induction of Metalloproteinase Expression

PubMed Central

Suchanski, Jaroslaw; Olbromski, Mateusz; Gomulkiewicz, Agnieszka; Owczarek, Tomasz; Kruczak, Anna; Ambicka, Aleksandra; Rys, Janusz; Ugorski, Maciej; Podhorska-Okolow, Marzena; Dziegiel, Piotr

2015-01-01

It has been recently found that metallothionein-3 (MT3) enhances the invasiveness and tumorigenesis of prostate cancer cells. This finding is in contrast to those of earlier studies, which indicated that overexpression of MT3 in breast cancer and prostate cancer cell lines inhibits their growth in vitro. Therefore, to clarify the role of MT3 in breast cancer progression, we analyzed the effect of MT3-overexpression on proliferation, invasiveness, migration, and tumorigenesis of breast cancer MDA-MB-231/BO2 cells. It was found that MDA-MB-231/BO2 cells overexpressing MT3 were characterized by increased invasiveness in vitro, compared to the control cells. Interestingly, this increased invasiveness correlated with a highly increased concentration of MMP3 in the culture supernatants (p<0.0001). Our data suggest that MT3 may regulate breast cancer cell invasiveness by modulating the expression of MMP3. These experimental results, obtained using triple-negative MDA-MB-231/BO2 cells, were further supported by clinical data. It was found that, in triple-negative breast cancer (TNBC), nuclear MT3 immunoreactivity in cancer cells tended to be associated with patients’ shorter disease-specific survival, suggesting that nuclear MT3 expression may be a potential marker of poor prognosis of triple-negative TNBC cases. PMID:25933064

Analysis of the myosins encoded in the recently completed Arabidopsis thaliana genome sequence

NASA Technical Reports Server (NTRS)

Reddy, A. S.; Day, I. S.

2001-01-01

BACKGROUND: Three types of molecular motors play an important role in the organization, dynamics and transport processes associated with the cytoskeleton. The myosin family of molecular motors move cargo on actin filaments, whereas kinesin and dynein motors move cargo along microtubules. These motors have been highly characterized in non-plant systems and information is becoming available about plant motors. The actin cytoskeleton in plants has been shown to be involved in processes such as transportation, signaling, cell division, cytoplasmic streaming and morphogenesis. The role of myosin in these processes has been established in a few cases but many questions remain to be answered about the number, types and roles of myosins in plants. RESULTS: Using the motor domain of an Arabidopsis myosin we identified 17 myosin sequences in the Arabidopsis genome. Phylogenetic analysis of the Arabidopsis myosins with non-plant and plant myosins revealed that all the Arabidopsis myosins and other plant myosins fall into two groups - class VIII and class XI. These groups contain exclusively plant or algal myosins with no animal or fungal myosins. Exon/intron data suggest that the myosins are highly conserved and that some may be a result of gene duplication. CONCLUSIONS: Plant myosins are unlike myosins from any other organisms except algae. As a percentage of the total gene number, the number of myosins is small overall in Arabidopsis compared with the other sequenced eukaryotic genomes. There are, however, a large number of class XI myosins. The function of each myosin has yet to be determined.

Melatonin induction and its role in high light stress tolerance in Arabidopsis thaliana.

PubMed

Lee, Hyoung Yool; Back, Kyoungwhan

2018-05-16

In plants, melatonin is a potent bioactive molecule involved in the response against various biotic and abiotic stresses. However, little is known of its defensive role against high light (HL) stress. In this study, we found that melatonin was transiently induced in response to HL stress in Arabidopsis thaliana with a simultaneous increase in the expression of melatonin biosynthetic genes, including serotonin N-acetyltransferase1 (SNAT1). Transient induction of melatonin was also observed in the flu mutant, a singlet oxygen ( 1 O 2 )-producing mutant, upon light exposure, suggestive of melatonin induction by chloroplastidic 1 O 2 against HL stress. An Arabidopsis snat1 mutant was devoid of melatonin induction upon HL stress, resulting in high susceptibility to HL stress. Exogenous melatonin treatment mitigated damage caused by HL stress in the snat1 mutant by reducing O 2 - production and increasing the expression of various ROS-responsive genes. In analogy, an Arabidopsis SNAT1-overexpressing line showed increased tolerance of HL stress concomitant with a reduction in malondialdehyde and ion leakage. A complementation line expressing an Arabidopsis SNAT1 genomic fragment in the snat1 mutant completely restored HL stress susceptibility in the snat1 mutant to levels comparable to that of wild-type Col-0 plants. The results of the analysis of several Arabidopsis genetic lines reveal for the first time at the genetic level that melatonin is involved in conferring HL stress tolerance in plants. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Arabidopsis CAPRICE (MYB) and GLABRA3 (bHLH) Control Tomato (Solanum lycopersicum) Anthocyanin Biosynthesis

PubMed Central

Wada, Takuji; Kunihiro, Asuka; Tominaga-Wada, Rumi

2014-01-01

In Arabidopsis thaliana the MYB transcription factor CAPRICE (CPC) and the bHLH transcription factor GLABRA3 (GL3) are central regulators of root-hair differentiation and trichome initiation. By transforming the orthologous tomato genes SlTRY (CPC) and SlGL3 (GL3) into Arabidopsis, we demonstrated that these genes influence epidermal cell differentiation in Arabidopsis, suggesting that tomato and Arabidopsis partially use similar transcription factors for epidermal cell differentiation. CPC and GL3 are also known to be involved in anthocyanin biosynthesis. After transformation into tomato, 35S::CPC inhibited anthocyanin accumulation, whereas GL3::GL3 enhanced anthocyanin accumulation. Real-time reverse transcription PCR analyses showed that the expression of anthocyanin biosynthetic genes including Phe-ammonia lyase (PAL), the flavonoid pathway genes chalcone synthase (CHS), dihydroflavonol reductase (DFR), and anthocyanidin synthase (ANS) were repressed in 35S::CPC tomato. In contrast, the expression levels of PAL, CHS, DFR, and ANS were significantly higher in GL3::GL3 tomato compared with control plants. These results suggest that CPC and GL3 also influence anthocyanin pigment synthesis in tomato. PMID:25268379

MIPS Arabidopsis thaliana Database (MAtDB): an integrated biological knowledge resource for plant genomics

PubMed Central

Schoof, Heiko; Ernst, Rebecca; Nazarov, Vladimir; Pfeifer, Lukas; Mewes, Hans-Werner; Mayer, Klaus F. X.

2004-01-01

Arabidopsis thaliana is the most widely studied model plant. Functional genomics is intensively underway in many laboratories worldwide. Beyond the basic annotation of the primary sequence data, the annotated genetic elements of Arabidopsis must be linked to diverse biological data and higher order information such as metabolic or regulatory pathways. The MIPS Arabidopsis thaliana database MAtDB aims to provide a comprehensive resource for Arabidopsis as a genome model that serves as a primary reference for research in plants and is suitable for transfer of knowledge to other plants, especially crops. The genome sequence as a common backbone serves as a scaffold for the integration of data, while, in a complementary effort, these data are enhanced through the application of state-of-the-art bioinformatics tools. This information is visualized on a genome-wide and a gene-by-gene basis with access both for web users and applications. This report updates the information given in a previous report and provides an outlook on further developments. The MAtDB web interface can be accessed at http://mips.gsf.de/proj/thal/db. PMID:14681437

Comparisons with Caenorhabditis (approximately 100 Mb) and Drosophila (approximately 175 Mb) using flow cytometry show genome size in Arabidopsis to be approximately 157 Mb and thus approximately 25% larger than the Arabidopsis genome initiative estimate of approximately 125 Mb.

PubMed

Bennett, Michael D; Leitch, Ilia J; Price, H James; Johnston, J Spencer

2003-04-01

Recent genome sequencing papers have given genome sizes of 180 Mb for Drosophila melanogaster Iso-1 and 125 Mb for Arabidopsis thaliana Columbia. The former agrees with early cytochemical estimates, but numerous cytometric estimates of around 170 Mb imply that a genome size of 125 Mb for arabidopsis is an underestimate. In this study, nuclei of species pairs were compared directly using flow cytometry. Co-run Columbia and Iso-1 female gave a 2C peak for arabidopsis only approx. 15 % below that for drosophila, and 16C endopolyploid Columbia nuclei had approx. 15 % more DNA than 2C chicken nuclei (with >2280 Mb). Caenorhabditis elegans Bristol N2 (genome size approx. 100 Mb) co-run with Columbia or Iso-1 gave a 2C peak for drosophila approx. 75 % above that for 2C C. elegans, and a 2C peak for arabidopsis approx. 57 % above that for C. elegans. This confirms that 1C in drosophila is approx. 175 Mb and, combined with other evidence, leads us to conclude that the genome size of arabidopsis is not approx. 125 Mb, but probably approx. 157 Mb. It is likely that the discrepancy represents extra repeated sequences in unsequenced gaps in heterochromatic regions. Complete sequencing of the arabidopsis genome until no gaps remain at telomeres, nucleolar organizing regions or centromeres is still needed to provide the first precise angiosperm C-value as a benchmark calibration standard for plant genomes, and to ensure that no genes have been missed in arabidopsis, especially in centromeric regions, which are clearly larger than once imagined.

Adjustment of growth and central metabolism to a mild but sustained nitrogen-limitation in Arabidopsis.

PubMed

Tschoep, Hendrik; Gibon, Yves; Carillo, Petronia; Armengaud, Patrick; Szecowka, Marek; Nunes-Nesi, Adriano; Fernie, Alisdair R; Koehl, Karin; Stitt, Mark

2009-03-01

We have established a simple soil-based experimental system that allows a small and sustained restriction of growth of Arabidopsis by low nitrogen (N). Plants were grown in a large volume of a peat-vermiculite mix that contained very low levels of inorganic N. As a control, inorganic N was added in solid form to the peat-vermiculite mix, or plants were grown in conventional nutrient-rich solids. The low N growth regime led to a sustained 20% decrease of the relative growth rate over a period of 2 weeks, resulting in a two- to threefold decrease in biomass in 35- to 40-day-old plants. Plants in the low N regime contained lower levels of nitrate, lower nitrate reductase activity, lower levels of malate, fumarate and other organic acids and slightly higher levels of starch, as expected from published studies of N-limited plants. However, their rosette protein content was unaltered, and total and many individual amino acid levels increased compared with N-replete plants. This metabolic phenotype reveals that Arabidopsis responds adaptively to low N by decreasing the rate of growth, while maintaining the overall protein content, and maintaining or even increasing the levels of many amino acids.

PAUSED Encodes the Arabidopsis Exportin-t Ortholog1

PubMed Central

Hunter, Christine A.; Aukerman, Milo J.; Sun, Hui; Fokina, Maria; Poethig, R. Scott

2003-01-01

Los1p/exportin-t (XPOT) mediates the nuclear export of tRNAs in yeast and mammals. The requirements for this transport pathway are unclear, however, because los1 mutations do not affect yeast growth, and the phenotype of XPOT mutations in mammals is unknown. Here, we show that PAUSED (PSD) is the Arabidopsis ortholog of LOS1/XPOT and is capable of rescuing the tRNA export defect of los1 in Brewer's yeast (Saccharomyces cerevisiae), suggesting that its function has been conserved. Putative null alleles of PSD disrupt the initiation of the shoot apical meristem and delay leaf initiation after germination, the emergence of the radicle and lateral roots, and the transition to flowering. Plants doubly mutant for psd and hasty, the Arabidopsis ortholog of exportin 5, are viable but have a more severe phenotype than either single mutant. These results suggest that PSD plays a role in tRNA export in Arabidopsis, but that at least one—and perhaps several—additional tRNA export pathways also exist. The PSD transcript is broadly expressed during development and is alternatively spliced in the 3′-untranslated region. No temporal or spatial difference in the abundance of different splice forms was observed. We propose that the mutant phenotype of psd reflects defects in developmental events and cell/tissue types that require elevated levels of protein synthesis and are therefore acutely sensitive to a reduction in tRNA export. PMID:12913168

Identification and biochemical characterization of an Arabidopsis indole-3-acetic acid glucosyltransferase.

PubMed

Jackson, R G; Lim, E K; Li, Y; Kowalczyk, M; Sandberg, G; Hoggett, J; Ashford, D A; Bowles, D J

2001-02-09

Biochemical characterization of recombinant gene products following a phylogenetic analysis of the UDP-glucosyltransferase (UGT) multigene family of Arabidopsis has identified one enzyme (UGT84B1) with high activity toward the plant hormone indole-3-acetic acid (IAA) and three related enzymes (UGT84B2, UGT75B1, and UGT75B2) with trace activities. The identity of the IAA conjugate has been confirmed to be 1-O-indole acetyl glucose ester. A sequence annotated as a UDP-glucose:IAA glucosyltransferase (IAA-UGT) in the Arabidopsis genome and expressed sequence tag data bases given its similarity to the maize iaglu gene sequence showed no activity toward IAA. This study describes the first biochemical analysis of a recombinant IAA-UGT and provides the foundation for future genetic approaches to understand the role of 1-O-indole acetyl glucose ester in Arabidopsis.

Reporter Gene-Facilitated Detection of Compounds in Arabidopsis Leaf Extracts that Activate the Karrikin Signaling Pathway.

PubMed

Sun, Yueming K; Flematti, Gavin R; Smith, Steven M; Waters, Mark T

2016-01-01

Karrikins are potent germination stimulants generated by the combustion of plant matter. Treatment of Arabidopsis with karrikins triggers a signaling process that is dependent upon a putative receptor protein KARRIKIN INSENSITIVE 2 (KAI2). KAI2 is a homolog of DWARF 14 (D14), the receptor for endogenous strigolactone hormones. Genetic analyses suggest that KAI2 also perceives endogenous signal(s) that are not strigolactones. Activation of KAI2 by addition of karrikins to Arabidopsis plants induces expression of transcripts including D14-LIKE 2 ( DLK2 ). We constructed the synthetic reporter gene DLK2 : LUC in Arabidopsis , which comprises the firefly luciferase gene ( LUC ) driven by the DLK2 promoter. Here we describe a luminescence-based reporter assay with Arabidopsis seeds to detect chemical signals that can activate the KAI2 signaling pathway. We demonstrate that the DLK2 : LUC assay can selectively and sensitively detect karrikins and a functionally similar synthetic strigolactone analog. Crucially we show that crude extracts from Arabidopsis leaves can also activate DLK2 : LUC in a KAI2-dependent manner. Our work provides the first direct evidence for the existence of endogenous chemical signals that can activate the KAI2-mediated signaling pathway in Arabidopsis . This sensitive reporter system can now be used for the bioassay-guided purification and identification of putative endogenous KAI2 ligands or their precursors, and endogenous compounds that might modulate the KAI2 signaling pathway.

Reporter Gene-Facilitated Detection of Compounds in Arabidopsis Leaf Extracts that Activate the Karrikin Signaling Pathway

PubMed Central

Sun, Yueming K.; Flematti, Gavin R.; Smith, Steven M.; Waters, Mark T.

2016-01-01

Karrikins are potent germination stimulants generated by the combustion of plant matter. Treatment of Arabidopsis with karrikins triggers a signaling process that is dependent upon a putative receptor protein KARRIKIN INSENSITIVE 2 (KAI2). KAI2 is a homolog of DWARF 14 (D14), the receptor for endogenous strigolactone hormones. Genetic analyses suggest that KAI2 also perceives endogenous signal(s) that are not strigolactones. Activation of KAI2 by addition of karrikins to Arabidopsis plants induces expression of transcripts including D14-LIKE 2 (DLK2). We constructed the synthetic reporter gene DLK2:LUC in Arabidopsis, which comprises the firefly luciferase gene (LUC) driven by the DLK2 promoter. Here we describe a luminescence-based reporter assay with Arabidopsis seeds to detect chemical signals that can activate the KAI2 signaling pathway. We demonstrate that the DLK2:LUC assay can selectively and sensitively detect karrikins and a functionally similar synthetic strigolactone analog. Crucially we show that crude extracts from Arabidopsis leaves can also activate DLK2:LUC in a KAI2-dependent manner. Our work provides the first direct evidence for the existence of endogenous chemical signals that can activate the KAI2-mediated signaling pathway in Arabidopsis. This sensitive reporter system can now be used for the bioassay-guided purification and identification of putative endogenous KAI2 ligands or their precursors, and endogenous compounds that might modulate the KAI2 signaling pathway. PMID:27994609

Expression and Protein Interaction Analyses Reveal Combinatorial Interactions of LBD Transcription Factors During Arabidopsis Pollen Development.

PubMed

Kim, Mirim; Kim, Min-Jung; Pandey, Shashank; Kim, Jungmook

2016-11-01

LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factor gene family members play key roles in diverse aspects of plant development. LBD10 and LBD27 have been shown to be essential for pollen development in Arabidopsis thaliana. From the previous RNA sequencing (RNA-Seq) data set of Arabidopsis pollen, we identified the mRNAs of LBD22, LBD25 and LBD36 in addition to LBD10 and LBD27 in Arabidopsis pollen. Here we conducted expression and cellular analysis using GFP:GUS (green fluorescent protein:β-glucuronidase) reporter gene and subcellular localization assays using LBD:GFP fusion proteins expressed under the control of their own promoters in Arabidopsis. We found that these LBD proteins display spatially and temporally distinct and overlapping expression patterns during pollen development. Bimolecular fluorescence complementation and GST (glutathione S-transferase) pull-down assays demonstrated that protein-protein interactions occur among the LBDs exhibiting overlapping expression during pollen development. We further showed that LBD10, LBD22, LBD25, LBD27 and LBD36 interact with each other to form heterodimers, which are localized to the nucleus in Arabidopsis protoplasts. Taken together, these results suggest that combinatorial interactions among LBD proteins may be important for their function in pollen development in Arabidopsis. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Characteristics and significance of intergenic polyadenylated RNA transcription in Arabidopsis.

PubMed

Moghe, Gaurav D; Lehti-Shiu, Melissa D; Seddon, Alex E; Yin, Shan; Chen, Yani; Juntawong, Piyada; Brandizzi, Federica; Bailey-Serres, Julia; Shiu, Shin-Han

2013-01-01

The Arabidopsis (Arabidopsis thaliana) genome is the most well-annotated plant genome. However, transcriptome sequencing in Arabidopsis continues to suggest the presence of polyadenylated (polyA) transcripts originating from presumed intergenic regions. It is not clear whether these transcripts represent novel noncoding or protein-coding genes. To understand the nature of intergenic polyA transcription, we first assessed its abundance using multiple messenger RNA sequencing data sets. We found 6,545 intergenic transcribed fragments (ITFs) occupying 3.6% of Arabidopsis intergenic space. In contrast to transcribed fragments that map to protein-coding and RNA genes, most ITFs are significantly shorter, are expressed at significantly lower levels, and tend to be more data set specific. A surprisingly large number of ITFs (32.1%) may be protein coding based on evidence of translation. However, our results indicate that these "translated" ITFs tend to be close to and are likely associated with known genes. To investigate if ITFs are under selection and are functional, we assessed ITF conservation through cross-species as well as within-species comparisons. Our analysis reveals that 237 ITFs, including 49 with translation evidence, are under strong selective constraint and relatively distant from annotated features. These ITFs are likely parts of novel genes. However, the selective pressure imposed on most ITFs is similar to that of randomly selected, untranscribed intergenic sequences. Our findings indicate that despite the prevalence of ITFs, apart from the possibility of genomic contamination, many may be background or noisy transcripts derived from "junk" DNA, whose production may be inherent to the process of transcription and which, on rare occasions, may act as catalysts for the creation of novel genes.

Benzoylsalicylic acid derivatives as defense activators in tobacco and Arabidopsis.

PubMed

Kamatham, Samuel; Pallu, Reddanna; Pasupulati, Anil Kumar; Singh, Surya Satyanarayana; Gudipalli, Padmaja

2017-11-01

Systemic acquired resistance (SAR) is a long lasting inducible whole plant immunity often induced by either pathogens or chemical elicitors. Salicylic acid (SA) is a known SAR signal against a broad spectrum of pathogens in plants. In a recent study, we have reported that benzoylsalicylic acid (BzSA) is a SAR inducer in tobacco and Arabidopsis plants. Here, we have synthesized BzSA derivatives using SA and benzoyl chlorides of various moieties as substrates. The chemical structures of BzSA derivatives were elucidated using Infrared spectroscopy (IR), Nuclear magnetic spectroscopy (NMR) and High-resolution mass spectrometer (HRMS) analysis. The bioefficacy of BzSA derivatives in inducing defense response against tobacco mosaic virus (TMV) was investigated in tobacco and SA abolished transgenic NahG Arabidopsis plants. Interestingly, pre-treatment of local leaves of tobacco with BzSA derivatives enhanced the expression of SAR genes such as NPR1 [Non-expressor of pathogenesis-related (PR) genes 1], PR and other defense marker genes (HSR203, SIPK, WIPK) in systemic leaves. Pre-treatment of BzSA derivatives reduced the spread of TMV infection to uninfected areas by restricting lesion number and diameter both in local and systemic leaves of tobacco in a dose-dependent manner. Furthermore, pre-treatment of BzSA derivatives in local leaves of SA deficient Arabidopsis NahG plants induced SAR through AtPR1 and AtPR5 gene expression and reduced leaf necrosis and curling symptoms in systemic leaves as compared to BzSA. These results suggest that BzSA derivatives are potent SAR inducers against TMV in tobacco and Arabidopsis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biochemical and immunocytological characterizations of Arabidopsis pollen tube cell wall.

PubMed

Dardelle, Flavien; Lehner, Arnaud; Ramdani, Yasmina; Bardor, Muriel; Lerouge, Patrice; Driouich, Azeddine; Mollet, Jean-Claude

2010-08-01

During plant sexual reproduction, pollen germination and tube growth require development under tight spatial and temporal control for the proper delivery of the sperm cells to the ovules. Pollen tubes are fast growing tip-polarized cells able to perceive multiple guiding signals emitted by the female organ. Adhesion of pollen tubes via cell wall molecules may be part of the battery of signals. In order to study these processes, we investigated the cell wall characteristics of in vitro-grown Arabidopsis (Arabidopsis thaliana) pollen tubes using a combination of immunocytochemical and biochemical techniques. Results showed a well-defined localization of cell wall epitopes. Low esterified homogalacturonan epitopes were found mostly in the pollen tube wall back from the tip. Xyloglucan and arabinan from rhamnogalacturonan I epitopes were detected along the entire tube within the two wall layers and the outer wall layer, respectively. In contrast, highly esterified homogalacturonan and arabinogalactan protein epitopes were found associated predominantly with the tip region. Chemical analysis of the pollen tube cell wall revealed an important content of arabinosyl residues (43%) originating mostly from (1-->5)-alpha-L-arabinan, the side chains of rhamnogalacturonan I. Finally, matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of endo-glucanase-sensitive xyloglucan showed mass spectra with two dominant oligosaccharides (XLXG/XXLG and XXFG), both being mono O-acetylated, and accounting for over 68% of the total ion signals. These findings demonstrate that the Arabidopsis pollen tube wall has its own characteristics compared with other cell types in the Arabidopsis sporophyte. These structural features are discussed in terms of pollen tube cell wall biosynthesis and growth dynamics.

Activity of Icacinol from Icacina trichantha on Seedling Growth of Oryza sativa and Arabidopsis thaliana.

PubMed

Zhao, Ming; Guo, Brian; Onakpa, Michael M; Wong, Tiffany; Wakasa, Kyo; Che, Chun-Tao; Warpeha, Katherine

2017-12-22

Broadleaf weeds are very costly for crop growers. Additional herbicidal compounds need to be obtained, especially from natural sources. Extracts of Icacina trichantha were evaluated for responses in germinating seeds and seedlings of rice (Oryza sativa) and Arabidopsis (Arabidopsis thaliana). An ethyl acetate fraction of I. trichantha tuber and a diterpenoid constituent, icacinol (1), were found to have impacts on germination and growth of seedlings. The seed germination inhibitory activity on rice was minimal, but significant on Arabidopsis. While rice indicated some growth delay in leaf expansion in the presence of 1, the effects appeared temporary; chlorophyll and anthocyanins were not significantly altered compared to DMSO controls. Rice seedlings attained biomass similar to DMSO controls, and rice grains per panicle were not significantly different from the DMSO controls. On the other hand, Arabidopsis exhibited damage to leaf expansion, reduced chlorophyll, and increased anthocyanins in aerial portions of the seedlings. Icacinol (1) may be a suitable chemical agent to investigate further for the treatment of eudicot weeds.

GDP-D-mannose epimerase regulates male gametophyte development, plant growth and leaf senescence in Arabidopsis.

PubMed

Qi, Tiancong; Liu, Zhipeng; Fan, Meng; Chen, Yan; Tian, Haixia; Wu, Dewei; Gao, Hua; Ren, Chunmei; Song, Susheng; Xie, Daoxin

2017-09-04

Plant GDP-D-mannose epimerase (GME) converts GDP-D-mannose to GDP-L-galactose, a precursor of both L-ascorbate (vitamin C) and cell wall polysaccharides. However, the genetic functions of GME in Arabidopsis are unclear. In this study, we found that mutations in Arabidopsis GME affect pollen germination, pollen tube elongation, and transmission and development of the male gametophyte through analysis of the heterozygous GME/gme plants and the homozygous gme plants. Arabidopsis gme mutants also exhibit severe growth defects and early leaf senescence. Surprisingly, the defects in male gametophyte in the gme plants are not restored by L-ascorbate, boric acid or GDP-L-galactose, though boric acid rescues the growth defects of the mutants, indicating that GME may regulate male gametophyte development independent of L-ascorbate and GDP-L-galactose. These results reveal key roles for Arabidopsis GME in reproductive development, vegetative growth and leaf senescence, and suggest that GME regulates plant growth and controls male gametophyte development in different manners.

The Role of Gravity on the Reproduction of Arabidopsis Plants

NASA Technical Reports Server (NTRS)

Hoshizaki, T.

1985-01-01

The presence of gravity as a necessary environmental factor for higher plants to complete their life cycle was examined. Arabidopsis thalliana (L.) Heynh. Columbia strain plants were grown continuously for three generations in a simulated micro-g environment as induced by horizontal clinostats. Growth, development and reproduction were followed. The Arabidopsis plants were selected for three generations on clinostats because: (1) a short life cycle of around 35 days; (2) the cells of third generation plants would in theory be free of gravity imprint; and (3) a third generation plant would therefore more than likely grow and respond like a plant growing in a micro-g environment. It is found that gravity is not a required environmental factor for higher plants to complete their life cycle, at least as tested by a horizontal clinostat. Clinostatting does not prevent the completion of the plant life cycle. However, clinostatting does appear to slow down the reproductive process of Arabidopsis plants. Whether higher plants can continue to reproduce for many generations in a true micro-g environment of space can only be determined by long duration experiments in space.

Systematic Analysis of Arabidopsis Organelles and a Protein Localization Database for Facilitating Fluorescent Tagging of Full-Length Arabidopsis Proteins1[W

PubMed Central

Li, Shijun; Ehrhardt, David W.; Rhee, Seung Y.

2006-01-01

Cells are organized into a complex network of subcellular compartments that are specialized for various biological functions. Subcellular location is an important attribute of protein function. To facilitate systematic elucidation of protein subcellular location, we analyzed experimentally verified protein localization data of 1,300 Arabidopsis (Arabidopsis thaliana) proteins. The 1,300 experimentally verified proteins are distributed among 40 different compartments, with most of the proteins localized to four compartments: mitochondria (36%), nucleus (28%), plastid (17%), and cytosol (13.3%). About 19% of the proteins are found in multiple compartments, in which a high proportion (36.4%) is localized to both cytosol and nucleus. Characterization of the overrepresented Gene Ontology molecular functions and biological processes suggests that the Golgi apparatus and peroxisome may play more diverse functions but are involved in more specialized processes than other compartments. To support systematic empirical determination of protein subcellular localization using a technology called fluorescent tagging of full-length proteins, we developed a database and Web application to provide preselected green fluorescent protein insertion position and primer sequences for all Arabidopsis proteins to study their subcellular localization and to store experimentally verified protein localization images, videos, and their annotations of proteins generated using the fluorescent tagging of full-length proteins technology. The database can be searched, browsed, and downloaded using a Web browser at http://aztec.stanford.edu/gfp/. The software can also be downloaded from the same Web site for local installation. PMID:16617091

Involvement of the Electrophilic Isothiocyanate Sulforaphane in Arabidopsis Local Defense Responses1

PubMed Central

Andersson, Mats X.; Nilsson, Anders K.; Johansson, Oskar N.; Boztaş, Gülin; Adolfsson, Lisa E.; Pinosa, Francesco; Petit, Christel Garcia; Aronsson, Henrik; Mackey, David; Tör, Mahmut; Hamberg, Mats; Ellerström, Mats

2015-01-01

Plants defend themselves against microbial pathogens through a range of highly sophisticated and integrated molecular systems. Recognition of pathogen-secreted effector proteins often triggers the hypersensitive response (HR), a complex multicellular defense reaction where programmed cell death of cells surrounding the primary site of infection is a prominent feature. Even though the HR was described almost a century ago, cell-to-cell factors acting at the local level generating the full defense reaction have remained obscure. In this study, we sought to identify diffusible molecules produced during the HR that could induce cell death in naive tissue. We found that 4-methylsulfinylbutyl isothiocyanate (sulforaphane) is released by Arabidopsis (Arabidopsis thaliana) leaf tissue undergoing the HR and that this compound induces cell death as well as primes defense in naive tissue. Two different mutants impaired in the pathogen-induced accumulation of sulforaphane displayed attenuated programmed cell death upon bacterial and oomycete effector recognition as well as decreased resistance to several isolates of the plant pathogen Hyaloperonospora arabidopsidis. Treatment with sulforaphane provided protection against a virulent H. arabidopsidis isolate. Glucosinolate breakdown products are recognized as antifeeding compounds toward insects and recently also as intracellular signaling and bacteriostatic molecules in Arabidopsis. The data presented here indicate that these compounds also trigger local defense responses in Arabidopsis tissue. PMID:25371552

Phylogeny-dominant classification of J-proteins in Arabidopsis thaliana and Brassica oleracea.

PubMed

Zhang, Bin; Qiu, Han-Lin; Qu, Dong-Hai; Ruan, Ying; Chen, Dong-Hong

2018-04-05

Hsp40s or DnaJ/J-proteins are evolutionarily conserved in all organisms as co-chaperones of molecular chaperone HSP70s that mainly participate in maintaining cellular protein homeostasis, such as protein folding, assembly, stabilization, and translocation under normal conditions as well as refolding and degradation under environmental stresses. It has been reported that Arabidopsis J-proteins are classified into four classes (types A-D) according to domain organization, but their phylogenetic relationships are unknown. Here, we identified 129 J-proteins in the world-wide popular vegetable Brassica oleracea, a close relative of the model plant Arabidopsis, and also revised the information of Arabidopsis J-proteins based on the latest online bioresources. According to phylogenetic analysis with domain organization and gene structure as references, the J-proteins from Arabidopsis and B. oleracea were classified into 15 main clades (I-XV) separated by a number of undefined small branches with remote relationship. Based on the number of members, they respectively belong to multigene clades, oligo-gene clades, and mono-gene clades. The J-protein genes from different clades may function together or separately to constitute a complicated regulatory network. This study provides a constructive viewpoint for J-protein classification and an informative platform for further functional dissection and resistant genes discovery related to genetic improvement of crop plants.

Analysis and visualization of Arabidopsis thaliana GWAS using web 2.0 technologies.

PubMed

Huang, Yu S; Horton, Matthew; Vilhjálmsson, Bjarni J; Seren, Umit; Meng, Dazhe; Meyer, Christopher; Ali Amer, Muhammad; Borevitz, Justin O; Bergelson, Joy; Nordborg, Magnus

2011-01-01

With large-scale genomic data becoming the norm in biological studies, the storing, integrating, viewing and searching of such data have become a major challenge. In this article, we describe the development of an Arabidopsis thaliana database that hosts the geographic information and genetic polymorphism data for over 6000 accessions and genome-wide association study (GWAS) results for 107 phenotypes representing the largest collection of Arabidopsis polymorphism data and GWAS results to date. Taking advantage of a series of the latest web 2.0 technologies, such as Ajax (Asynchronous JavaScript and XML), GWT (Google-Web-Toolkit), MVC (Model-View-Controller) web framework and Object Relationship Mapper, we have created a web-based application (web app) for the database, that offers an integrated and dynamic view of geographic information, genetic polymorphism and GWAS results. Essential search functionalities are incorporated into the web app to aid reverse genetics research. The database and its web app have proven to be a valuable resource to the Arabidopsis community. The whole framework serves as an example of how biological data, especially GWAS, can be presented and accessed through the web. In the end, we illustrate the potential to gain new insights through the web app by two examples, showcasing how it can be used to facilitate forward and reverse genetics research. Database URL: http://arabidopsis.usc.edu/

Cinnamate-4-hydroxylase expression in arabidopsis. Regulation in response to development and the environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell-Lelong, D.A.; Cusumano, J.C.; Meyer, K.

1997-03-01

Cinnamate-r-hydroxylase (C4H) is the first Cyt P450-dependent monooxygenase of the phenylpropanoid pathway. To study the expression of this gene in Arabidopsis thaliana, a C4H cDNA clone from the Arabidopsis expressed sequence tag database was identified and used to isolate its corresponding genomic clone. The entire C4H coding sequence plus 2.9 kb of its promoter were isolated on a 5.4-kb HindIII fragment of this cosmid. Inspection of the promoter sequence revealed the presence of a number of putative regulatory motifs previously identified in the promoters of other phenylpropanoid pathway genes. The expression of C4H was analyzed by RNA blot hybridization analysismore » and in transgenic Arabidopsis carrying a C4H-{beta}-glucuronidase transcriptional fusion. C4H message accumulation was light-dependent, but was detectable even in dark-grown seedlings. Consistent with these data, C4H mRNA was accumulated to light-grown levels in etiolated det1-1 mutant seedlings. C4H is widely expressed in various Arabidopsis tissues, particularly in roots and cells undergoing lignification. The C4H-driven {beta}-glucuronidase expression accurately reflected the tissue-specificity and wound-inducibility of the C4H promoter indicated by RNA blot hybridization analysis. A modest increase in C4H expression was observed in the tt8 mutant of Arabidopsis. 77 refs., 5 figs.« less

The Arabidopsis Halophytic Relative Thellungiella halophila Tolerates Nitrogen-Limiting Conditions by Maintaining Growth, Nitrogen Uptake, and Assimilation1[W][OA

PubMed Central

Kant, Surya; Bi, Yong-Mei; Weretilnyk, Elizabeth; Barak, Simon; Rothstein, Steven J.

2008-01-01

A comprehensive knowledge of mechanisms regulating nitrogen (N) use efficiency is required to reduce excessive input of N fertilizers while maintaining acceptable crop yields under limited N supply. Studying plant species that are naturally adapted to low N conditions could facilitate the identification of novel regulatory genes conferring better N use efficiency. Here, we show that Thellungiella halophila, a halophytic relative of Arabidopsis (Arabidopsis thaliana), grows better than Arabidopsis under moderate (1 mm nitrate) and severe (0.4 mm nitrate) N-limiting conditions. Thellungiella exhibited a lower carbon to N ratio than Arabidopsis under N limitation, which was due to Thellungiella plants possessing higher N content, total amino acids, total soluble protein, and lower starch content compared with Arabidopsis. Furthermore, Thellungiella had higher amounts of several metabolites, such as soluble sugars and organic acids, under N-sufficient conditions (4 mm nitrate). Nitrate reductase activity and NR2 gene expression in Thellungiella displayed less of a reduction in response to N limitation than in Arabidopsis. Thellungiella shoot GS1 expression was more induced by low N than in Arabidopsis, while in roots, Thellungiella GS2 expression was maintained under N limitation but was decreased in Arabidopsis. Up-regulation of NRT2.1 and NRT3.1 expression was higher and repression of NRT1.1 was lower in Thellungiella roots under N-limiting conditions compared with Arabidopsis. Differential transporter gene expression was correlated with higher nitrate influx in Thellungiella at low 15NO3− supply. Taken together, our results suggest that Thellungiella is tolerant to N-limited conditions and could act as a model system to unravel the mechanisms for low N tolerance. PMID:18467466

Decrease in Leaf Sucrose Synthesis Leads to Increased Leaf Starch Turnover and Decreased RuBP-limited Photosynthesis But Not Rubisco-limited Photosynthesis in Arabidopsis Null Mutants of SPSA1

USDA-ARS?s Scientific Manuscript database

SPS (Sucrose phosphate synthase) isoforms from dicots cluster into families A, B and C. In this study, we investigated the individual effect of null mutations of each of the four SPS genes in Arabidopsis (spsa1, spsa2, spsb and spsc) on photosynthesis and carbon partitioning. Null mutants spsa1 and ...

Systemic acquired resistance in soybean is regulated by two proteins, Orthologous to Arabidopsis NPR1.

PubMed

Sandhu, Devinder; Tasma, I Made; Frasch, Ryan; Bhattacharyya, Madan K

2009-08-05

Systemic acquired resistance (SAR) is induced in non-inoculated leaves following infection with certain pathogenic strains. SAR is effective against many pathogens. Salicylic acid (SA) is a signaling molecule of the SAR pathway. The development of SAR is associated with the induction of pathogenesis related (PR) genes. Arabidopsis non-expressor of PR1 (NPR1) is a regulatory gene of the SA signal pathway 123. SAR in soybean was first reported following infection with Colletotrichum trancatum that causes anthracnose disease. We investigated if SAR in soybean is regulated by a pathway, similar to the one characterized in Arabidopsis. Pathogenesis-related gene GmPR1 is induced following treatment of soybean plants with the SAR inducer, 2,6-dichloroisonicotinic acid (INA) or infection with the oomycete pathogen, Phytophthora sojae. In P. sojae-infected plants, SAR was induced against the bacterial pathogen, Pseudomonas syringae pv. glycinea. Soybean GmNPR1-1 and GmNPR1-2 genes showed high identities to Arabidopsis NPR1. They showed similar expression patterns among the organs, studied in this investigation. GmNPR1-1 and GmNPR1-2 are the only soybean homologues of NPR1and are located in homoeologous regions. In GmNPR1-1 and GmNPR1-2 transformed Arabidopsis npr1-1 mutant plants, SAR markers: (i) PR-1 was induced following INA treatment and (ii) BGL2 following infection with Pseudomonas syringae pv. tomato (Pst), and SAR was induced following Pst infection. Of the five cysteine residues, Cys82, Cys150, Cys155, Cys160, and Cys216 involved in oligomer-monomer transition in NPR1, Cys216 in GmNPR1-1 and GmNPR1-2 proteins was substituted to Ser and Leu, respectively. Complementation analyses in Arabidopsis npr1-1 mutants revealed that homoeologous GmNPR1-1 and GmNPR1-2 genes are orthologous to Arabidopsis NPR1. Therefore, SAR pathway in soybean is most likely regulated by GmNPR1 genes. Substitution of Cys216 residue, essential for oligomer-monomer transition of Arabidopsis NPR1

DNA demethylation in the Arabidopsis genome

PubMed Central

Penterman, Jon; Zilberman, Daniel; Huh, Jin Hoe; Ballinger, Tracy; Henikoff, Steven; Fischer, Robert L.

2007-01-01

Cytosine DNA methylation is considered to be a stable epigenetic mark, but active demethylation has been observed in both plants and animals. In Arabidopsis thaliana, DNA glycosylases of the DEMETER (DME) family remove methylcytosines from DNA. Demethylation by DME is necessary for genomic imprinting, and demethylation by a related protein, REPRESSOR OF SILENCING1, prevents gene silencing in a transgenic background. However, the extent and function of demethylation by DEMETER-LIKE (DML) proteins in WT plants is not known. Using genome-tiling microarrays, we mapped DNA methylation in mutant and WT plants and identified 179 loci actively demethylated by DML enzymes. Mutations in DML genes lead to locus-specific DNA hypermethylation. Reintroducing WT DML genes restores most loci to the normal pattern of methylation, although at some loci, hypermethylated epialleles persist. Of loci demethylated by DML enzymes, >80% are near or overlap genes. Genic demethylation by DML enzymes primarily occurs at the 5′ and 3′ ends, a pattern opposite to the overall distribution of WT DNA methylation. Our results show that demethylation by DML DNA glycosylases edits the patterns of DNA methylation within the Arabidopsis genome to protect genes from potentially deleterious methylation. PMID:17409185

Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction.

PubMed

Shi, Jinrui; Drummond, Bruce J; Wang, Hongyu; Archibald, Rayeann L; Habben, Jeffrey E

2016-08-01

The phytohormone ethylene regulates plant growth and development as well as plant response to environmental cues. ARGOS genes reduce plant sensitivity to ethylene when overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). A previous genetic study suggested that the endoplasmic reticulum and Golgi-localized maize ARGOS1 targets the ethylene signal transduction components at or upstream of CONSTITUTIVE TRIPLE RESPONSE1, but the mechanism of ARGOS modulating ethylene signaling is unknown. Here, we demonstrate in Arabidopsis that ZmARGOS1, as well as the Arabidopsis ARGOS homolog ORGAN SIZE RELATED1, physically interacts with Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1), an ethylene receptor interacting protein that regulates the activity of ETHYLENE RESPONSE1. The protein-protein interaction was also detected with the yeast split-ubiquitin two-hybrid system. Using the same yeast assay, we found that maize RTE1 homolog REVERSION-TO-ETHYLENE SENSITIVITY1 LIKE4 (ZmRTL4) and ZmRTL2 also interact with maize and Arabidopsis ARGOS proteins. Like AtRTE1 in Arabidopsis, ZmRTL4 and ZmRTL2 reduce ethylene responses when overexpressed in maize, indicating a similar mechanism for ARGOS regulating ethylene signaling in maize. A polypeptide fragment derived from ZmARGOS8, consisting of a Pro-rich motif flanked by two transmembrane helices that are conserved among members of the ARGOS family, can interact with AtRTE1 and maize RTL proteins in Arabidopsis. The conserved domain is necessary and sufficient to reduce ethylene sensitivity in Arabidopsis and maize. Overall, these results suggest a physical association between ARGOS and the ethylene receptor signaling complex via AtRTE1 and maize RTL proteins, supporting a role for ARGOS in regulating ethylene perception and the early steps of signal transduction in Arabidopsis and maize. © 2016 American Society of Plant Biologists. All Rights Reserved.

The role of CAX1 and CAX3 in elemental distribution and abundance in Arabidopsis seed

USDA-ARS?s Scientific Manuscript database

The ability to alter nutrient partitioning within plant cells is poorly understood. In Arabidopsis (Arabidopsis thaliana), a family of endomembrane cation exchangers (CAXs) transports Ca(2+) and other cations. However, experiments have not focused on how the distribution and partitioning of calcium ...

Gibberellins inhibit adventitious rooting in hybrid aspen and Arabidopsis by affecting auxin transport.

PubMed

Mauriat, Mélanie; Petterle, Anna; Bellini, Catherine; Moritz, Thomas

2014-05-01

Knowledge of processes involved in adventitious rooting is important to improve both fundamental understanding of plant physiology and the propagation of numerous plants. Hybrid aspen (Populus tremula × tremuloïdes) plants overexpressing a key gibberellin (GA) biosynthesis gene (AtGA20ox1) grow rapidly but have poor rooting efficiency, which restricts their clonal propagation. Therefore, we investigated the molecular basis of adventitious rooting in Populus and the model plant Arabidopsis. The production of adventitious roots (ARs) in tree cuttings is initiated from the basal stem region, and involves the interplay of several endogenous and exogenous factors. The roles of several hormones in this process have been characterized, but the effects of GAs have not been fully investigated. Here, we show that a GA treatment negatively affects the numbers of ARs produced by wild-type hybrid aspen cuttings. Furthermore, both hybrid aspen plants and intact Arabidopsis seedlings overexpressing AtGA20ox1, PttGID1.1 or PttGID1.3 genes (with a 35S promoter) produce few ARs, although ARs develop from the basal stem region of hybrid aspen and the hypocotyl of Arabidopsis. In Arabidopsis, auxin and strigolactones are known to affect AR formation. Our data show that the inhibitory effect of GA treatment on adventitious rooting is not mediated by perturbation of the auxin signalling pathway, or of the strigolactone biosynthetic and signalling pathways. Instead, GAs appear to act by perturbing polar auxin transport, in particular auxin efflux in hybrid aspen, and both efflux and influx in Arabidopsis. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

Genome-wide identification of lineage-specific genes in Arabidopsis, Oryza and Populus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xiaohan; Jawdy, Sara; Tschaplinski, Timothy J

2009-01-01

Protein sequences were compared among Arabidopsis, Oryza and Populus to identify differential gene (DG) sets that are in one but not the other two genomes. The DG sets were screened against a plant transcript database, the NR protein database and six newly-sequenced genomes (Carica, Glycine, Medicago, Sorghum, Vitis and Zea) to identify a set of species-specific genes (SS). Gene expression, protein motif and intron number were examined. 192, 641 and 109 SS genes were identified in Arabidopsis, Oryza and Populus, respectively. Some SS genes were preferentially expressed in flowers, roots, xylem and cambium or up-regulated by stress. Six conserved motifsmore » in Arabidopsis and Oryza SS proteins were found in other distant lineages. The SS gene sets were enriched with intronless genes. The results reflect functional and/or anatomical differences between monocots and eudicots or between herbaceous and woody plants. The Populus-specific genes are candidates for carbon sequestration and biofuel research.« less

Biochemical properties and subcellular localization of tyrosine aminotransferases in Arabidopsis thaliana.

PubMed

Wang, Minmin; Toda, Kyoko; Maeda, Hiroshi A

2016-12-01

Plants produce various L-tyrosine (Tyr)-derived compounds that are of pharmaceutical or nutritional importance to humans. Tyr aminotransferase (TAT) catalyzes the reversible transamination between Tyr and 4-hydroxyphenylpyruvate (HPP), the initial step in the biosynthesis of many Tyr-derived plant natural products. Herein reported is the biochemical characterization and subcellular localization of TAT enzymes from the model plant Arabidopsis thaliana. Phylogenetic analysis showed that Arabidopsis has at least two homologous TAT genes, At5g53970 (AtTAT1) and At5g36160 (AtTAT2). Their recombinant enzymes showed distinct biochemical properties: AtTAT1 had the highest activity towards Tyr, while AtTAT2 exhibited a broad substrate specificity for both amino and keto acid substrates. Also, AtTAT1 favored the direction of Tyr deamination to HPP, whereas AtTAT2 preferred transamination of HPP to Tyr. Subcellular localization analysis using GFP-fusion proteins and confocal microscopy showed that AtTAT1, AtTAT2, and HPP dioxygenase (HPPD), which catalyzes the subsequent step of TAT, are localized in the cytosol, unlike plastid-localized Tyr and tocopherol biosynthetic enzymes. Furthermore, subcellular fractionation indicated that, while HPPD activity is restricted to the cytosol, TAT activity is detected in both cytosolic and plastidic fractions of Arabidopsis leaf tissue, suggesting that an unknown aminotransferase(s) having TAT activity is also present in the plastids. Biochemical and cellular analyses of Arabidopsis TATs provide a fundamental basis for future in vivo studies and metabolic engineering for enhanced production of Tyr-derived phytochemicals in plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Partial Gene Sequencing of CYP1A, Vitellogenin, and Metallothionein in Mosquitofish Gambusia yucatana and Gambusia sexradiata.

PubMed

Vázquez-Euán, Roberto; Escalante-Herrera, Karla S; Rodríguez-Fuentes, Gabriela

2017-01-01

Ground characteristics in the Yucatan Peninsula make recovery and treatment of wastewater very expensive. This situation has contributed to an increase of pollutants in the aquifer. Unfortunately, studies related to the effects of those pollutants in native organisms are scarce. The aim of this work was to obtain partial sequences of widely known genes used as biomarkers of pollutant effect in Gambusia yucatana and Gambusia sexradiata. The studied genes were: cytochrome P450 1A (CYP1A); vitellogenin (VTG); metallothionein (MT), and two housekeeping genes, 18S and β-actin. From reported sequences of Gambusia affinis, primers were designed and amplification was done in the local Gambusia species exposed for 48 h to gasoline (100 µL/L, stirred for 24 h pre-exposure). Preliminary results revealed partial sequences of all genes with an approximate average length of 200 bp. BLAST analysis of found sequences indicated a minimum of 97% identity with reported sequences for G. affinis or Gambusia holbrooki showing great similarity.

Characterization and expression of a metallothionein gene in the aquatic fern Azolla filiculoides under heavy metal stress.

PubMed

Schor-Fumbarov, Tamar; Goldsbrough, Peter B; Adam, Zach; Tel-Or, Elisha

2005-12-01

A cDNA encoding a type 2 metallothionein (MT) was isolated from Azolla filiculoides, termed AzMT2, accession no. AF482470. The AzMT2 transcript was expressed in sterile A. filiculoides that were free of the cyanobiont Anabaena azollae after erythromycin treatment, proving that AzMT2 is encoded by the fern genome. AzMT2 RNA expression was enhanced by the addition of Cd(+2), Cu(+2), Zn(+2) and Ni(+2) to the growth medium. The transcript level of AzMT2 correlated with the metal content in the plants. Temporal analysis of AzMT2 expression demonstrated that Cd(2+) and Ni(2+) induction of AzMT2 RNA expression occurred within 48 h. AzMT2-enhanced expression responded more intensely to the toxic Cd and Ni ions in A. filiculoides suggesting that AzMT2 may participate in detoxification mechanism. The more moderate response of AzMT2 to Zn and Cu ions, which are essential micronutrients, suggest a role for AzMT2 in metal homeostasis.

Hepatic and renal metallothionein concentrations in Commerson's dolphins (Cephalorhynchus commersonii) from Tierra del Fuego, South Atlantic Ocean.

PubMed

Cáceres-Saez, Iris; Polizzi, Paula; Romero, Belén; Dellabianca, Natalia A; Ribeiro Guevara, Sergio; Goodall, R Natalie P; Cappozzo, H Luis; Gerpe, Marcela

2016-07-15

The Commerson's dolphin is the most common endemic odontocete of subantarctic waters of Tierra del Fuego, Argentina incidentally caught in fishing nets. The species is classified as "Data Deficient" by the IUCN. Metallothioneins (MTs) are considered as suitable biomarkers for health and environmental monitoring. The aims of the study were to assess MT concentrations in the liver and kidney of bycaught specimens. Moreover, correlations with Zn, Se, Cd, Ag and Hg, and the molar ratios of MT:metals were estimated to evaluate if there is an indication of their respective protective role against metal toxicity in tissues. Hepatic and renal MT concentrations were similar, ranging from 11.6 to 29.1nmol·g(-1) WW, and Kidney/Liver ratios ranging from 0.73 to 1.93 corresponded to normal ranges. Results suggest that MTs are related to physiological ranges for the species. This information constitutes the first MT report on Commerson's dolphins and possibly considered as baseline for species' conservation. Copyright © 2016 Elsevier Ltd. All rights reserved.

A gamma-glutamyl transpeptidase-independent pathway of glutathione catabolism to glutamate via 5-oxoproline in Arabidopsis.

PubMed

Ohkama-Ohtsu, Naoko; Oikawa, Akira; Zhao, Ping; Xiang, Chengbin; Saito, Kazuki; Oliver, David J

2008-11-01

The degradation pathway of glutathione (GSH) in plants is not well understood. In mammals, GSH is predominantly metabolized through the gamma-glutamyl cycle, where GSH is degraded by the sequential reaction of gamma-glutamyl transpeptidase (GGT), gamma-glutamyl cyclotransferase, and 5-oxoprolinase to yield glutamate (Glu) and dipeptides that are subject to peptidase action. In this study, we examined if GSH is degraded through the same pathway in Arabidopsis (Arabidopsis thaliana) as occurs in mammals. In Arabidopsis, the oxoprolinase knockout mutants (oxp1-1 and oxp1-2) accumulate more 5-oxoproline (5OP) and less Glu than wild-type plants, suggesting substantial metabolite flux though 5OP and that 5OP is a major contributor to Glu steady-state levels. In the ggt1-1/ggt4-1/oxp1-1 triple mutant with no GGT activity in any organs except young siliques, the 5OP concentration in leaves was not different from that in oxp1-1, suggesting that GGTs are not major contributors to 5OP production in Arabidopsis. 5OP formation strongly tracked the level of GSH in Arabidopsis plants, suggesting that GSH is the precursor of 5OP in a GGT-independent reaction. Kinetics analysis suggests that gamma-glutamyl cyclotransferase is the major source of GSH degradation and 5OP formation in Arabidopsis. This discovery led us to propose a new pathway for GSH turnover in plants where GSH is converted to 5OP and then to Glu by the combined action of gamma-glutamyl cyclotransferase and 5-oxoprolinase in the cytoplasm.

LONO1 Encoding a Nucleoporin Is Required for Embryogenesis and Seed Viability in Arabidopsis1[C][W][OA

PubMed Central

Braud, Christopher; Zheng, Wenguang; Xiao, Wenyan

2012-01-01

Early embryogenesis in Arabidopsis (Arabidopsis thaliana) is distinguished by a predictable pattern of cell divisions and is a good system for investigating mechanisms of developmental pattern formation. Here, we identified a gene called LONO1 (LNO1) in Arabidopsis in which mutations can abolish the first asymmetrical cell division of the zygote, alter planes and number of cell divisions in early embryogenesis, and eventually arrest embryo development. LNO1 is highly expressed in anthers of flower buds, stigma papilla of open flowers, and embryo and endosperm during early embryogenesis, which is correlated with its functions in reproductive development. The homozygous lno1-1 seed is not viable. LNO1, a homolog of the nucleoporin NUP214 in human (Homo sapiens) and Nup159 in yeast (Saccharomyces cerevisiae), encodes a nucleoporin protein containing phenylalanine-glycine repeats in Arabidopsis. We demonstrate that LNO1 can functionally complement the defect in the yeast temperature-sensitive nucleoporin mutant nup159. We show that LNO1 specifically interacts with the Arabidopsis DEAD-box helicase/ATPase LOS4 in the yeast two-hybrid assay. Furthermore, mutations in AtGLE1, an Arabidopsis homolog of the yeast Gle1 involved in the same poly(A) mRNA export pathway as Nup159, also result in seed abortion. Our results suggest that LNO1 is a component of the nuclear pore complex required for mature mRNA export from the nucleus to the cytoplasm, which makes LNO1 essential for embryogenesis and seed viability in Arabidopsis. PMID:22898497

Molecular Screening Tools to Study Arabidopsis Transcription Factors

PubMed Central

Wehner, Nora; Weiste, Christoph; Dröge-Laser, Wolfgang

2011-01-01

In the model plant Arabidopsis thaliana, more than 2000 genes are estimated to encode transcription factors (TFs), which clearly emphasizes the importance of transcriptional control. Although genomic approaches have generated large TF open reading frame (ORF) collections, only a limited number of these genes is functionally characterized, yet. This review evaluates strategies and methods to identify TF functions. In particular, we focus on two recently developed TF screening platforms, which make use of publically available GATEWAY®-compatible ORF collections. (1) The Arabidopsis thaliana TF ORF over-Expression (AtTORF-Ex) library provides pooled collections of transgenic lines over-expressing HA-tagged TF genes, which are suited for screening approaches to define TF functions in stress defense and development. (2) A high-throughput microtiter plate based protoplast trans activation (PTA) system has been established to screen for TFs which are regulating a given promoter:Luciferase construct in planta. PMID:22645547

Towards systems biology of the gravity response of higher plants -multiscale analysis of Arabidopsis thaliana root growth

NASA Astrophysics Data System (ADS)

Palme, Klaus; Aubry, D.; Bensch, M.; Schmidt, T.; Ronneberger, O.; Neu, C.; Li, X.; Wang, H.; Santos, F.; Wang, B.; Paponov, I.; Ditengou, F. A.; Teale, W. T.; Volkmann, D.; Baluska, F.; Nonis, A.; Trevisan, S.; Ruperti, B.; Dovzhenko, A.

Gravity plays a fundamental role in plant growth and development. Up to now, little is known about the molecular organisation of the signal transduction cascades and networks which co-ordinate gravity perception and response. By using an integrated systems biological approach, a systems analysis of gravity perception and the subsequent tightly-regulated growth response is planned in the model plant Arabidopsis thaliana. This approach will address questions such as: (i) what are the components of gravity signal transduction pathways? (ii) what are the dynamics of these components? (iii) what is their spatio-temporal regulation in different tis-sues? Using Arabidopsis thaliana as a model-we use root growth to obtain insights in the gravity response. New techniques enable identification of the individual genes affected by grav-ity and further integration of transcriptomics and proteomics data into interaction networks and cell communication events that operate during gravitropic curvature. Using systematic multiscale analysis we have identified regulatory networks consisting of transcription factors, the protein degradation machinery, vesicle trafficking and cellular signalling during the gravire-sponse. We developed approach allowing to incorporate key features of the root system across all relevant spatial and temporal scales to describe gene-expression patterns and correlate them with individual gene and protein functions. Combination of high-resolution microscopy and novel computational tools resulted in development of the root 3D model in which quantitative descriptions of cellular network properties and of multicellular interactions important in root growth and gravitropism can be integrated for the first time.

Terpenoid Metabolism in Wild-Type and Transgenic Arabidopsis PlantsW⃞

PubMed Central

Aharoni, Asaph; Giri, Ashok P.; Deuerlein, Stephan; Griepink, Frans; de Kogel, Willem-Jan; Verstappen, Francel W. A.; Verhoeven, Harrie A.; Jongsma, Maarten A.; Schwab, Wilfried; Bouwmeester, Harro J.

2003-01-01

Volatile components, such as terpenoids, are emitted from aerial parts of plants and play a major role in the interaction between plants and their environment. Analysis of the composition and emission pattern of volatiles in the model plant Arabidopsis showed that a range of volatile components are released, primarily from flowers. Most of the volatiles detected were monoterpenes and sesquiterpenes, which in contrast to other volatiles showed a diurnal emission pattern. The active terpenoid metabolism in wild-type Arabidopsis provoked us to conduct an additional set of experiments in which transgenic Arabidopsis overexpressing two different terpene synthases were generated. Leaves of transgenic plants constitutively expressing a dual linalool/nerolidol synthase in the plastids (FaNES1) produced linalool and its glycosylated and hydroxylated derivatives. The sum of glycosylated components was in some of the transgenic lines up to 40- to 60-fold higher than the sum of the corresponding free alcohols. Surprisingly, we also detected the production and emission of nerolidol, albeit at a low level, suggesting that a small pool of its precursor farnesyl diphosphate is present in the plastids. Transgenic lines with strong transgene expression showed growth retardation, possibly as a result of the depletion of isoprenoid precursors in the plastids. In dual-choice assays with Myzus persicae, the FaNES1-expressing lines significantly repelled the aphids. Overexpression of a typical cytosolic sesquiterpene synthase resulted in the production of only trace amounts of the expected sesquiterpene, suggesting tight control of the cytosolic pool of farnesyl diphosphate, the precursor for sesquiterpenoid biosynthesis. This study further demonstrates the value of Arabidopsis for studies of the biosynthesis and ecological role of terpenoids and provides new insights into their metabolism in wild-type and transgenic plants. PMID:14630967

Plasticity of the Arabidopsis Root System under Nutrient Deficiencies1[C][W][OPEN

PubMed Central

Gruber, Benjamin D.; Giehl, Ricardo F.H.; Friedel, Swetlana; von Wirén, Nicolaus

2013-01-01

Plant roots show a particularly high variation in their morphological response to different nutrient deficiencies. Although such changes often determine the nutrient efficiency or stress tolerance of plants, it is surprising that a comprehensive and comparative analysis of root morphological responses to different nutrient deficiencies has not yet been conducted. Since one reason for this is an inherent difficulty in obtaining nutrient-deficient conditions in agar culture, we first identified conditions appropriate for producing nutrient-deficient plants on agar plates. Based on a careful selection of agar specifically for each nutrient being considered, we grew Arabidopsis (Arabidopsis thaliana) plants at four levels of deficiency for 12 nutrients and quantified seven root traits. In combination with measurements of biomass and elemental concentrations, we observed that the nutritional status and type of nutrient determined the extent and type of changes in root system architecture (RSA). The independent regulation of individual root traits further pointed to a differential sensitivity of root tissues to nutrient limitations. To capture the variation in RSA under different nutrient supplies, we used principal component analysis and developed a root plasticity chart representing the overall modulations in RSA under a given treatment. This systematic comparison of RSA responses to nutrient deficiencies provides a comprehensive view of the overall changes in root plasticity induced by the deficiency of single nutrients and provides a solid basis for the identification of nutrient-sensitive steps in the root developmental program. PMID:23852440

Mutations in a new Arabidopsis cyclophilin disrupt its interaction with protein phosphatase 2A

NASA Technical Reports Server (NTRS)

Jackson, K.; Soll, D.; Evans, M. L. (Principal Investigator)

1999-01-01

The heterotrimeric protein phosphatase 2A (PP2A) is a component of multiple signaling pathways in eukaryotes. Disruption of PP2A activity in Arabidopsis is known to alter auxin transport and growth response pathways. We demonstrated that the regulatory subunit A of an Arabidopsis PP2A interacts with a novel cyclophilin, ROC7. The gene for this cyclophilin encodes a protein that contains a unique 30-amino acid extension at the N-terminus, which distinguishes the gene product from all previously identified Arabidopsis cyclophilins. Altered forms of ROC7 cyclophilin with mutations in the conserved DENFKL domain did not bind to PP2A. Unlike protein phosphatase 2B, PP2A activity in Arabidopsis extracts was not affected by the presence of the cyclophilin-binding molecule cyclosporin. The ROC7 transcript was expressed to high levels in all tissues tested. Expression of an ROC7 antisense transcript gave rise to increased root growth. These results indicate that cyclophilin may have a role in regulating PP2A activity, by a mechanism that differs from that employed for cyclophilin regulation of PP2B.

Positive regulatory role of sound vibration treatment in Arabidopsis thaliana against Botrytis cinerea infection.

PubMed

Choi, Bosung; Ghosh, Ritesh; Gururani, Mayank Anand; Shanmugam, Gnanendra; Jeon, Junhyun; Kim, Jonggeun; Park, Soo-Chul; Jeong, Mi-Jeong; Han, Kyung-Hwan; Bae, Dong-Won; Bae, Hanhong

2017-05-30

Sound vibration (SV), a mechanical stimulus, can trigger various molecular and physiological changes in plants like gene expression, hormonal modulation, induced antioxidant activity and calcium spiking. It also alters the seed germination and growth of plants. In this study, we investigated the effects of SV on the resistance of Arabidopsis thaliana against Botrytis cinerea infection. The microarray analysis was performed on infected Arabidopsis plants pre-exposed to SV of 1000 Hertz with 100 decibels. Broadly, the transcriptomic analysis revealed up-regulation of several defense and SA-responsive and/or signaling genes. Quantitative real-time PCR (qRT-PCR) analysis of selected genes also validated the induction of SA-mediated response in the infected Arabidopsis plants pre-exposed to SV. Corroboratively, hormonal analysis identified the increased concentration of salicylic acid (SA) in the SV-treated plants after pathogen inoculation. In contrast, jasmonic acid (JA) level in the SV-treated plants remained stable but lower than control plants during the infection. Based on these findings, we propose that SV treatment invigorates the plant defense system by regulating the SA-mediated priming effect, consequently promoting the SV-induced resistance in Arabidopsis against B. cinerea.

The development of spaceflight experiments with Arabidopsis as a model system in gravitropism studies

NASA Technical Reports Server (NTRS)

Katembe, W. J.; Edelmann, R. E.; Brinckmann, E.; Kiss, J. Z.

1998-01-01

Experiments with Arabidopsis have been developed for spaceflight studies in the European Space Agency's Biorack module. The Biorack is a multiuser facility that is flown on the United States Space Shuttle and serves as a small laboratory for studying cell and developmental biology in unicells, plants, and small invertebrates. The purpose of our spaceflight research was to investigate the starch-statolith model for gravity perception by studying wild-type (WT) and three starch-deficient mutants of Arabidopsis. Since spaceflight opportunities for biological experimentation are scarce, the extensive ground-based testing described in this paper is needed to ensure the success of a flight project. Therefore, the specific aims of our ground-based research were: (1) to modify the internal configuration of the flight hardware, which originally was designed for large lentil seeds, to accommodate small Arabidopsis seeds; (2) to maximize seed germination in the hardware; and (3) to develop favorable conditions in flight hardware for the growth and gravitropism of seedlings. The hardware has been modified, and growth conditions for Arabidopsis have been optimized. These experiments were successfully flown on two Space Shuttle missions in 1997.

The Arabidopsis Information Resource (TAIR): a comprehensive database and web-based information retrieval, analysis, and visualization system for a model plant

PubMed Central

Huala, Eva; Dickerman, Allan W.; Garcia-Hernandez, Margarita; Weems, Danforth; Reiser, Leonore; LaFond, Frank; Hanley, David; Kiphart, Donald; Zhuang, Mingzhe; Huang, Wen; Mueller, Lukas A.; Bhattacharyya, Debika; Bhaya, Devaki; Sobral, Bruno W.; Beavis, William; Meinke, David W.; Town, Christopher D.; Somerville, Chris; Rhee, Seung Yon

2001-01-01

Arabidopsis thaliana, a small annual plant belonging to the mustard family, is the subject of study by an estimated 7000 researchers around the world. In addition to the large body of genetic, physiological and biochemical data gathered for this plant, it will be the first higher plant genome to be completely sequenced, with completion expected at the end of the year 2000. The sequencing effort has been coordinated by an international collaboration, the Arabidopsis Genome Initiative (AGI). The rationale for intensive investigation of Arabidopsis is that it is an excellent model for higher plants. In order to maximize use of the knowledge gained about this plant, there is a need for a comprehensive database and information retrieval and analysis system that will provide user-friendly access to Arabidopsis information. This paper describes the initial steps we have taken toward realizing these goals in a project called The Arabidopsis Information Resource (TAIR) (www.arabidopsis.org). PMID:11125061

STI. DE-FG02-00ER1505 [Brief summary of 11th International Conference on Arabidopsis Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2000-06-24

The 11th International Conference on Arabidopsis Research was held in Madison, Wisconsin, June 24 through June 28, 2000. Arabidopsis thaliana has been the subject of genetic study for many years. However, during the last decade, the number of research laboratories using Arabidopsis as a model system has increased tremendously, and Arabidopsis is currently being used to study all aspects of plant biology. The rapid rate of progress in Arabidopsis research, including the completion of the genomic sequence, underscores the usefulness of holding a meeting every year. These conferences provide an important opportunity for the Arabidopsis community to interact and exchangemore » information. The meeting opened with an evening keynote address on the global impact of plant biology, delivered by Richard Jefferson, the Executive Director of CAMBIA (Center for the Application of Molecular Biology to International Agriculture). This was followed by short updates from each of the NSF-funded Plant Genome groups. Many of these groups are carrying out projects that impact the Arabidopsis community. Each of the 17 platform sessions consisted of talks from two invited speakers followed by two short talks that were chosen from the submitted poster abstracts. A concerted effort was made to invite junior investigators, including graduate students and postdocs, to give these talks. Posters were available for viewing during three formal sessions, and, because the poster session was adjacent to the lecture hall, it was easy for participants to go back and forth between posters and lectures. Finally, a mixer and an informal banquet provided opportunities for participants to meet new people and renew acquaintances. Furthermore, the registration package included all lunches and dinners together in a cafeteria next to the posters and lecture hall, thus encouraging the meeting of established investigators with students and postdocs. The North American Arabidopsis Steering Committee (elected

Lil3 dimerization and chlorophyll binding in Arabidopsis thaliana.

PubMed

Mork-Jansson, Astrid Elisabeth; Gargano, Daniela; Kmiec, Karol; Furnes, Clemens; Shevela, Dmitriy; Eichacker, Lutz Andreas

2015-10-07

The two-helix light harvesting like (Lil) protein Lil3 belongs to the family of chlorophyll binding light harvesting proteins of photosynthetic membranes. A function in tetrapyrrol synthesis and stabilization of geranylgeraniol reductase has been shown. Lil proteins contain the chlorophyll a/b-binding motif; however, binding of chlorophyll has not been demonstrated. We find that Lil3.2 from Arabidopsis thaliana forms heterodimers with Lil3.1 and binds chlorophyll. Lil3.2 heterodimerization (25±7.8 nM) is favored relative to homodimerization (431±59 nM). Interaction of Lil3.2 with chlorophyll a (231±49 nM) suggests that heterodimerization precedes binding of chlorophyll in Arabidopsis thaliana. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Infrared microspectroscopic imaging of plant tissues: spectral visualization of Triticum aestivum kernel and Arabidopsis leaf microstructure

PubMed Central

Warren, Frederick J; Perston, Benjamin B; Galindez-Najera, Silvia P; Edwards, Cathrina H; Powell, Prudence O; Mandalari, Giusy; Campbell, Grant M; Butterworth, Peter J; Ellis, Peter R

2015-01-01

Infrared microspectroscopy is a tool with potential for studies of the microstructure, chemical composition and functionality of plants at a subcellular level. Here we present the use of high-resolution bench top-based infrared microspectroscopy to investigate the microstructure of Triticum aestivum L. (wheat) kernels and Arabidopsis leaves. Images of isolated wheat kernel tissues and whole wheat kernels following hydrothermal processing and simulated gastric and duodenal digestion were generated, as well as images of Arabidopsis leaves at different points during a diurnal cycle. Individual cells and cell walls were resolved, and large structures within cells, such as starch granules and protein bodies, were clearly identified. Contrast was provided by converting the hyperspectral image cubes into false-colour images using either principal component analysis (PCA) overlays or by correlation analysis. The unsupervised PCA approach provided a clear view of the sample microstructure, whereas the correlation analysis was used to confirm the identity of different anatomical structures using the spectra from isolated components. It was then demonstrated that gelatinized and native starch within cells could be distinguished, and that the loss of starch during wheat digestion could be observed, as well as the accumulation of starch in leaves during a diurnal period. PMID:26400058

Phytochrome A-specific signaling in Arabidopsis thaliana

PubMed Central

Kircher, Stefan; Terecskei, Kata; Wolf, Iris; Sipos, Mark

2011-01-01

Among the five phytochromes in Arabidopsis thaliana, phytochrome A (phyA) plays a major role in seedling de-etiolation. Until now more then ten positive and some negative components acting downstream of phyA have been identified. However, their site of action and hierarchical relationships are not completely understood yet. PMID:22067110

Synthesis of Hydroxylated Sterols in Transgenic Arabidopsis Plants Alters Growth and Steroid Metabolism1[C][W][OA

PubMed Central

Beste, Lisa; Nahar, Nurun; Dalman, Kerstin; Fujioka, Shozo; Jonsson, Lisbeth; Dutta, Paresh C.; Sitbon, Folke

2011-01-01

To explore mechanisms in plant sterol homeostasis, we have here increased the turnover of sterols in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum) plants by overexpressing four mouse cDNA encoding cholesterol hydroxylases (CHs), hydroxylating cholesterol at the C-7, C-24, C-25, or C-27 positions. Compared to the wild type, the four types of Arabidopsis transformant showed varying degrees of phenotypic alteration, the strongest one being in CH25 lines, which were dark-green dwarfs resembling brassinosteroid-related mutants. Gas chromatography-mass spectrometry analysis of extracts from wild-type Arabidopsis plants revealed trace levels of α and β forms of 7-hydroxycholesterol, 7-hydroxycampesterol, and 7-hydroxysitosterol. The expected hydroxycholesterol metabolites in CH7-, CH24-, and CH25 transformants were identified and quantified using gas chromatography-mass spectrometry. Additional hydroxysterol forms were also observed, particularly in CH25 plants. In CH24 and CH25 lines, but not in CH7 ones, the presence of hydroxysterols was correlated with a considerable alteration of the sterol profile and an increased sterol methyltransferase activity in microsomes. Moreover, CH25 lines contained clearly reduced levels of brassinosteroids, and displayed an enhanced drought tolerance. Equivalent transformations of potato plants with the CH25 construct increased hydroxysterol levels, but without the concomitant alteration of growth and sterol profiles observed in Arabidopsis. The results suggest that an increased hydroxylation of cholesterol and/or other sterols in Arabidopsis triggers compensatory processes, acting to maintain sterols at adequate levels. PMID:21746809

Arabidopsis thaliana alpha1,2-glucosyltransferase (ALG10) is required for efficient N-glycosylation and leaf growth

PubMed Central

Farid, Akhlaq; Pabst, Martin; Schoberer, Jennifer; Altmann, Friedrich; Glössl, Josef; Strasser, Richard

2011-01-01

Assembly of the dolichol-linked oligosaccharide precursor (Glc3Man9GlcNAc2) is highly conserved among eukaryotes. In contrast to yeast and mammals, little is known about the biosynthesis of dolichol-linked oligosaccharides and the transfer to asparagine residues of nascent polypeptides in plants. To understand the biological function of these processes in plants we characterized the Arabidopsis thaliana homolog of yeast ALG10, the α1,2-glucosyltransferase that transfers the terminal glucose residue to the lipid-linked precursor. Expression of an Arabidopsis ALG10–GFP fusion protein in Nicotiana benthamiana leaf epidermal cells revealed a reticular distribution pattern resembling endoplasmic reticulum (ER) localization. Analysis of lipid-linked oligosaccharides showed that Arabidopsis ALG10 can complement the yeast Δalg10 mutant strain. A homozygous Arabidopsis T-DNA insertion mutant (alg10-1) accumulated mainly lipid-linked Glc2Man9GlcNAc2 and displayed a severe protein underglycosylation defect. Phenotypic analysis of alg10-1 showed that mutant plants have altered leaf size when grown in soil. Moreover, the inactivation of ALG10 in Arabidopsis resulted in the activation of the unfolded protein response, increased salt sensitivity and suppression of the phenotype of α-glucosidase I-deficient plants. In summary, these data show that Arabidopsis ALG10 is an ER-resident α1,2-glucosyltransferase that is required for lipid-linked oligosaccharide biosynthesis and subsequently for normal leaf development and abiotic stress response. PMID:21707802

Abscisic acid negatively regulates post-penetration resistance of Arabidopsis to the biotrophic powdery mildew fungus.

PubMed

Xiao, Xiang; Cheng, Xi; Yin, Kangquan; Li, Huali; Qiu, Jin-Long

2017-08-01

Pytohormone abscisic acid (ABA) plays important roles in defense responses. Nonetheless, how ABA regulates plant resistance to biotrophic fungi remains largely unknown. Arabidopsis ABA-deficient mutants, aba2-1 and aba3-1, displayed enhanced resistance to the biotrophic powdery mildew fungus Golovinomyces cichoracearum. Moreover, exogenously administered ABA increased the susceptibility of Arabidopsis to G. cichoracearum. Arabidopsis ABA perception components mutants, abi1-1 and abi2-1, also displayed similar phenotypes to ABA-deficient mutants in resistance to G. cichoracearum. However, the resistance to G. cichoracearum is not changed in downstream ABA signaling transduction mutants, abi3-1, abi4-1, and abi5-1. Microscopic examination revealed that hyphal growth and conidiophore production of G. cichoracearum were compromised in the ABA deficient mutants, even though pre-penetration and penetration growth of the fungus were not affected. In addition, salicylic acid (SA) and MPK3 are found to be involved in ABA-regulated resistance to G. cichoracearum. Our work demonstrates that ABA negatively regulates post-penetration resistance of Arabidopsis to powdery mildew fungus G. cichoracearum, probably through antagonizing the function of SA.

Chitosan oligosaccharide induces resistance to Tobacco mosaic virus in Arabidopsis via the salicylic acid-mediated signalling pathway

PubMed Central

Jia, Xiaochen; Meng, Qingshan; Zeng, Haihong; Wang, Wenxia; Yin, Heng

2016-01-01

Chitosan is one of the most abundant carbohydrate biopolymers in the world, and chitosan oligosaccharide (COS), which is prepared from chitosan, is a plant immunity regulator. The present study aimed to validate the effect of COS on inducing resistance to tobacco mosaic virus (TMV) in Arabidopsis and to investigate the potential defence-related signalling pathways involved. Optimal conditions for the induction of TMV resistance in Arabidopsis were COS pretreatment at 50 mg/L for 1 day prior to inoculation with TMV. Multilevel indices, including phenotype data, and TMV coat protein expression, revealed that COS induced TMV resistance in wild-type and jasmonic acid pathway- deficient (jar1) Arabidopsis plants, but not in salicylic acid pathway deficient (NahG) Arabidopsis plants. Quantitative-PCR and analysis of phytohormone levels confirmed that COS pretreatment enhanced the expression of the defence-related gene PR1, which is a marker of salicylic acid signalling pathway, and increased the amount of salicylic acid in WT and jar1, but not in NahG plants. Taken together, these results confirm that COS induces TMV resistance in Arabidopsis via activation of the salicylic acid signalling pathway. PMID:27189192

Chitosan oligosaccharide induces resistance to Tobacco mosaic virus in Arabidopsis via the salicylic acid-mediated signalling pathway.

PubMed

Jia, Xiaochen; Meng, Qingshan; Zeng, Haihong; Wang, Wenxia; Yin, Heng

2016-05-18

Chitosan is one of the most abundant carbohydrate biopolymers in the world, and chitosan oligosaccharide (COS), which is prepared from chitosan, is a plant immunity regulator. The present study aimed to validate the effect of COS on inducing resistance to tobacco mosaic virus (TMV) in Arabidopsis and to investigate the potential defence-related signalling pathways involved. Optimal conditions for the induction of TMV resistance in Arabidopsis were COS pretreatment at 50 mg/L for 1 day prior to inoculation with TMV. Multilevel indices, including phenotype data, and TMV coat protein expression, revealed that COS induced TMV resistance in wild-type and jasmonic acid pathway- deficient (jar1) Arabidopsis plants, but not in salicylic acid pathway deficient (NahG) Arabidopsis plants. Quantitative-PCR and analysis of phytohormone levels confirmed that COS pretreatment enhanced the expression of the defence-related gene PR1, which is a marker of salicylic acid signalling pathway, and increased the amount of salicylic acid in WT and jar1, but not in NahG plants. Taken together, these results confirm that COS induces TMV resistance in Arabidopsis via activation of the salicylic acid signalling pathway.

Comparison of arabidopsis stomatal density mutants indicates variation in water stress responses and potential epistatic effects

Treesearch

Shaneka S. Lawson; Paula M. Pijut; Charles H. Michler

2014-01-01

Recent physiological analysis of Arabidopsis stomatal density (SD) mutants indicated that SD was not the major factor controlling aboveground biomass accumulation. Despite the general theory that plants with fewer stomata have limited biomass acquisition capabilities, epf1 and several other Arabidopsis mutants varied significantly in leaf fresh...

Metallothionein in Hermetia illucens (Linnaeus, 1758) larvae (Diptera: Stratiomyidae), a potential biomarker for organic waste system.

PubMed

Wang, Xiaoyun; Gao, Qiao; Liu, Xinhui; Wang, Xiao-Ping; Lei, Chaoliang; Sayed, Waheed A A; Zhu, Fen

2018-02-01

Black soldier fly, Hermetia illucens (Linnaeus, 1758), is an important economic fly as its larvae can be used for recycling organic waste, such as food waste and manure. H. illucens larvae (BSFL) could uptake Cd from substrates and accumulate it inside bodies, which need to be monitored during waste treatment. Metallothionein (MT) usually serve as biomarker because of its role in metal homeostasis, detoxification, and dose response of heavy metals. Therefore, a MT gene was cloned from H. illucens (HIMT) that encoded 40 amino acids with typical cysteine rich features, which had a high sequence identity with other insect MTs. The expression of HIMT and total MT protein was measured in BSFL fed by meals spiked with gradient dose of Cd (0, 5, 50, 500 mg/kg) for 24, 48, 72, and 96 h, respectively. Dose-associated response of HIMT and total MT were found and the possible correlative range of Cd was from 5 to 50 mg/kg. The expression of HIMT might be a potential biomarker for monitoring Cd contamination by H. illucens in terrestrial organic matters, which might further apply in waste transformation system.

Arabidopsis WRKY45 transcription factor activates PHOSPHATE TRANSPORTER1;1 expression in response to phosphate starvation.

PubMed

Wang, Hui; Xu, Qian; Kong, You-Han; Chen, Yun; Duan, Jun-Ye; Wu, Wei-Hua; Chen, Yi-Fang

2014-04-01

The WRKY transcription factor family has more than 70 members in the Arabidopsis (Arabidopsis thaliana) genome, and some of them are involved in plant responses to biotic and abiotic stresses. This study evaluated the role of WRKY45 in regulating phosphate (Pi) uptake in Arabidopsis. WRKY45 was localized in the nucleus and mainly expressed in roots. During Pi starvation, WRKY45 expression was markedly induced, typically in roots. WRKY45 overexpression in Arabidopsis increased Pi content and uptake, while RNA interference suppression of WRKY45 decreased Pi content and uptake. Furthermore, the WRKY45-overexpressing lines were more sensitive to arsenate, the analog of Pi, compared with wild-type seedlings. These results indicate that WRKY45 positively regulates Arabidopsis Pi uptake. Quantitative real-time polymerase chain reaction and β-glucuronidase staining assays showed that PHOSPHATE TRANSPORTER1;1 (PHT1;1) expression was enhanced in the WRKY45-overexpressing lines and slightly repressed in the WRKY45 RNA interference line. Chromatin immunoprecipitation and electrophoretic mobility shift assay results indicated that WRKY45 can bind to two W-boxes within the PHT1;1 promoter, confirming the role of WRKY45 in directly up-regulating PHT1;1 expression. The pht1;1 mutant showed decreased Pi content and uptake, and overexpression of PHT1;1 resulted in enhanced Pi content and uptake. Furthermore, the PHT1;1-overexpressing line was much more sensitive to arsenate than WRKY45-overexpressing and wild-type seedlings, indicating that PHT1;1 overexpression can enhance Arabidopsis Pi uptake. Moreover, the enhanced Pi uptake and the increased arsenate sensitivity of the WRKY45-overexpressing line was impaired by pht1;1 (35S:WRKY45-18::pht1;1), demonstrating an epistatic genetic regulation between WRKY45 and PHT1;1. Together, our results demonstrate that WRKY45 is involved in Arabidopsis response to Pi starvation by direct up-regulation of PHT1;1 expression.

Reproductive Toxicity and Life History Study of Silver Nanoparticle Effect, Uptake and Transport in Arabidopsis thaliana

PubMed Central

Geisler-Lee, Jane; Brooks, Marjorie; Gerfen, Jacob R.; Wang, Qiang; Fotis, Christin; Sparer, Anthony; Ma, Xingmao; Berg, R. Howard; Geisler, Matt

2014-01-01

Concerns about nanotechnology have prompted studies on how the release of these engineered nanoparticles impact our environment. Herein, the impact of 20 nm silver nanoparticles (AgNPs) on the life history traits of Arabidopsis thaliana was studied in both above- and below-ground parts, at macroscopic and microscopic scales. Both gross phenotypes (in contrast to microscopic phenotypes) and routes of transport and accumulation were investigated from roots to shoots. Wild type Arabidopsis growing in soil, regularly irrigated with 75 μg/L of AgNPs, did not show any obvious morphological change. However, their vegetative development was prolonged by two to three days and their reproductive growth shortened by three to four days. In addition, the germination rates of offspring decreased drastically over three generations. These findings confirmed that AgNPs induce abiotic stress and cause reproductive toxicity in Arabidopsis. To trace transport of AgNPs, this study also included an Arabidopsis reporter line genetically transformed with a green fluorescent protein and grown in an optical transparent medium with 75 μg/L AgNPs. AgNPs followed three routes: (1) At seven days after planting (DAP) at S1.0 (stages defined by Boyes et al. 2001 [41]), AgNPs attached to the surface of primary roots and then entered their root tips; (2) At 14 DAP at S1.04, as primary roots grew longer, AgNPs gradually moved into roots and entered new lateral root primordia and root hairs; (3) At 17 DAP at S1.06 when the Arabidopsis root system had developed multiple lateral roots, AgNPs were present in vascular tissue and throughout the whole plant from root to shoot. In some cases, if cotyledons of the Arabidopsis seedlings were immersed in melted transparent medium, then AgNPs were taken up by and accumulated in stomatal guard cells. These findings in Arabidopsis are the first to document specific routes and rates of AgNP uptake in vivo and in situ. PMID:28344224

Improved n-butanol production via co-expression of membrane-targeted tilapia metallothionein and the clostridial metabolic pathway in Escherichia coli.

PubMed

Chin, Wei-Chih; Lin, Kuo-Hsing; Liu, Chun-Chi; Tsuge, Kenji; Huang, Chieh-Chen

2017-04-11

N-Butanol has favorable characteristics for use as either an alternative fuel or platform chemical. Bio-based n-butanol production using microbes is an emerging technology that requires further development. Although bio-industrial microbes such as Escherichia coli have been engineered to produce n-butanol, reactive oxygen species (ROS)-mediated toxicity may limit productivity. Previously, we show that outer-membrane-targeted tilapia metallothionein (OmpC-TMT) is more effective as an ROS scavenger than human and mouse metallothioneins to reduce oxidative stress in the host cell. The host strain (BUT1-DE) containing the clostridial n-butanol pathway displayed a decreased growth rate and limited n-butanol productivity, likely due to ROS accumulation. The clostridial n-butanol pathway was co-engineered with inducible OmpC-TMT in E. coli (BUT3-DE) for simultaneous ROS removal, and its effect on n-butanol productivity was examined. The ROS scavenging ability of cells overexpressing OmpC-TMT was examined and showed an approximately twofold increase in capacity. The modified strain improved n-butanol productivity to 320 mg/L, whereas the control strain produced only 95.1 mg/L. Transcriptomic analysis revealed three major KEGG pathways that were significantly differentially expressed in the BUT3-DE strain compared with their expression in the BUT1-DE strain, including genes involved in oxidative phosphorylation, fructose and mannose metabolism and glycolysis/gluconeogenesis. These results indicate that OmpC-TMT can increase n-butanol production by scavenging ROS. The transcriptomic analysis suggested that n-butanol causes quinone malfunction, resulting in oxidative-phosphorylation-related nuo operon downregulation, which would diminish the ability to convert NADH to NAD + and generate proton motive force. However, fructose and mannose metabolism-related genes (fucA, srlE and srlA) were upregulated, and glycolysis/gluconeogenesis-related genes (pfkB, pgm) were

Effect of thermal processing and canning on cadmium and lead levels in California market squid: the role of metallothioneins.

PubMed

Galitsopoulou, A; Georgantelis, D; Kontominas, M G

2013-01-01

The effects of two common seafood preparation practices (roasting and industrial canning) on the heavy metal content--cadmium (Cd) and lead (Pb)--of various tissues of California market squid were studied. Emphasis was placed on the role of metallothioneins (MT) in Cd and Pb behaviour during processing. Cd and Pb analysis was conducted by a Zeeman GTA-AAS atomic absorption spectrometry system; MT analysis was performed by a mercury saturation assay. Results showed that Cd levels in the mantle and whole squid were considerably affected by both processing practices, reaching a 240% increase in mantle and a 40% increase in whole squid. Interestingly, Cd behaviour was associated with MT changes during squid processing. On the other hand, Pb content was not affected from either processing or associated with MT content in the raw or processed squid. Therefore, processing operations may affect Cd and Pb content differently due to the specific metal bioaccumulation and chemical features of each heavy metal type.

Arabidopsis dynamin-related protein 1A polymers bind, but do not tubulate, liposomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Backues, Steven K.; Bednarek, Sebastian Y., E-mail: sybednar@wisc.edu

2010-03-19

The Arabidopsis dynamin-related protein 1A (AtDRP1A) is involved in endocytosis and cell plate maturation in Arabidopsis. Unlike dynamin, AtDRP1A does not have any recognized membrane binding or protein-protein interaction domains. We report that GTPase active AtDRP1A purified from Escherichia coli as a fusion to maltose binding protein forms homopolymers visible by negative staining electron microscopy. These polymers interact with protein-free liposomes whose lipid composition mimics that of the inner leaflet of the Arabidopsis plasma membrane, suggesting that lipid-binding may play a role in AtDRP1A function. However, AtDRP1A polymers do not appear to assemble and disassemble in a dynamic fashion andmore » do not have the ability to tubulate liposomes in vitro, suggesting that additional factors or modifications are necessary for AtDRP1A's in vivo function.« less

Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction[OPEN

PubMed Central

Shi, Jinrui; Wang, Hongyu; Habben, Jeffrey E.

2016-01-01

The phytohormone ethylene regulates plant growth and development as well as plant response to environmental cues. ARGOS genes reduce plant sensitivity to ethylene when overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). A previous genetic study suggested that the endoplasmic reticulum and Golgi-localized maize ARGOS1 targets the ethylene signal transduction components at or upstream of CONSTITUTIVE TRIPLE RESPONSE1, but the mechanism of ARGOS modulating ethylene signaling is unknown. Here, we demonstrate in Arabidopsis that ZmARGOS1, as well as the Arabidopsis ARGOS homolog ORGAN SIZE RELATED1, physically interacts with Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1), an ethylene receptor interacting protein that regulates the activity of ETHYLENE RESPONSE1. The protein-protein interaction was also detected with the yeast split-ubiquitin two-hybrid system. Using the same yeast assay, we found that maize RTE1 homolog REVERSION-TO-ETHYLENE SENSITIVITY1 LIKE4 (ZmRTL4) and ZmRTL2 also interact with maize and Arabidopsis ARGOS proteins. Like AtRTE1 in Arabidopsis, ZmRTL4 and ZmRTL2 reduce ethylene responses when overexpressed in maize, indicating a similar mechanism for ARGOS regulating ethylene signaling in maize. A polypeptide fragment derived from ZmARGOS8, consisting of a Pro-rich motif flanked by two transmembrane helices that are conserved among members of the ARGOS family, can interact with AtRTE1 and maize RTL proteins in Arabidopsis. The conserved domain is necessary and sufficient to reduce ethylene sensitivity in Arabidopsis and maize. Overall, these results suggest a physical association between ARGOS and the ethylene receptor signaling complex via AtRTE1 and maize RTL proteins, supporting a role for ARGOS in regulating ethylene perception and the early steps of signal transduction in Arabidopsis and maize. PMID:27268962

Arabidopsis genotypes resistant and susceptible to diamondback moth (Lepidoptera: Putellidea): No net effects on insect growth

USDA-ARS?s Scientific Manuscript database

Plutella xylostella (L.), diamondback moth (DBM) is a destructive pest of the Brassicaceae including Arabidopsis thaliana (L.) Heynhold. Ecotypes of Arabidopsis vary in the amounts of leaf area consumed when fed on by DBM, which has been used as a measure of resistance to DBM. Recombinant inbred lin...

RNA Silencing of Exocyst Genes in the Stigma Impairs the Acceptance of Compatible Pollen in Arabidopsis1[OPEN

PubMed Central

Safavian, Darya; Indriolo, Emily; Chapman, Laura; Ahmed, Abdalla

2015-01-01

Initial pollen-pistil interactions in the Brassicaceae are regulated by rapid communication between pollen grains and stigmatic papillae and are fundamentally important, as they are the first step toward successful fertilization. The goal of this study was to examine the requirement of exocyst subunits, which function in docking secretory vesicles to sites of polarized secretion, in the context of pollen-pistil interactions. One of the exocyst subunit genes, EXO70A1, was previously identified as an essential factor in the stigma for the acceptance of compatible pollen in Arabidopsis (Arabidopsis thaliana) and Brassica napus. We hypothesized that EXO70A1, along with other exocyst subunits, functions in the Brassicaceae dry stigma to deliver cargo-bearing secretory vesicles to the stigmatic papillar plasma membrane, under the pollen attachment site, for pollen hydration and pollen tube entry. Here, we investigated the functions of exocyst complex genes encoding the remaining seven subunits, SECRETORY3 (SEC3), SEC5, SEC6, SEC8, SEC10, SEC15, and EXO84, in Arabidopsis stigmas following compatible pollinations. Stigma-specific RNA-silencing constructs were used to suppress the expression of each exocyst subunit individually. The early postpollination stages of pollen grain adhesion, pollen hydration, pollen tube penetration, seed set, and overall fertility were analyzed in the transgenic lines to evaluate the requirement of each exocyst subunit. Our findings provide comprehensive evidence that all eight exocyst subunits are necessary in the stigma for the acceptance of compatible pollen. Thus, this work implicates a fully functional exocyst complex as a component of the compatible pollen response pathway to promote pollen acceptance. PMID:26443677

Ectopic expression of pumpkin gibberellin oxidases alters gibberellin biosynthesis and development of transgenic Arabidopsis plants.

PubMed

Radi, Abeer; Lange, Theo; Niki, Tomoya; Koshioka, Masaji; Lange, Maria João Pimenta

2006-02-01

Immature pumpkin (Cucurbita maxima) seeds contain gibberellin (GA) oxidases with unique catalytic properties resulting in GAs of unknown function for plant growth and development. Overexpression of pumpkin GA 7-oxidase (CmGA7ox) in Arabidopsis (Arabidopsis thaliana) resulted in seedlings with elongated roots, taller plants that flower earlier with only a little increase in bioactive GA4 levels compared to control plants. In the same way, overexpression of the pumpkin GA 3-oxidase1 (CmGA3ox1) resulted in a GA overdose phenotype with increased levels of endogenous GA4. This indicates that, in Arabidopsis, 7-oxidation and 3-oxidation are rate-limiting steps in GA plant hormone biosynthesis that control plant development. With an opposite effect, overexpression of pumpkin seed-specific GA 20-oxidase1 (CmGA20ox1) in Arabidopsis resulted in dwarfed plants that flower late with reduced levels of GA4 and increased levels of physiological inactive GA17 and GA25 and unexpected GA34 levels. Severe dwarfed plants were obtained by overexpression of the pumpkin GA 2-oxidase1 (CmGA2ox1) in Arabidopsis. This dramatic change in phenotype was accompanied by a considerable decrease in the levels of bioactive GA4 and an increase in the corresponding inactivation product GA34 in comparison to control plants. In this study, we demonstrate the potential of four pumpkin GA oxidase-encoding genes to modulate the GA plant hormone pool and alter plant stature and development.

Metallothionein, a marker of antiapoptosis, is associated with clinical forms of oral lichen planus.

PubMed

Allon, Irit; Ofir, Merav; Vered, Hanna; Hirshberg, Abraham

2014-11-01

To investigate the expression of anti- and proapoptosis markers, metallothionein (MT), and caspase-2, in the epithelial and inflammatory cells of oral lichen planus (OLP) patients, and to investigate the association with clinical parameters. Included were biopsies of 70 OLP patients. The clinical data were collected from patients' charts. The expression of MT and caspase-2 was immunomorphometrically analyzed in the epithelial and inflammatory cells, and the results were correlated with the clinical presentation. The epithelial and inflammatory cells expressed MT (10.2 ± 5.75 and 0.68 ± 0.86) and caspase-2 (1.54 ± 2.6 and 0.98 ± 1.15) which show a trend toward an inverse expression. The expression of MT in the epithelium was significantly higher in patients presenting with keratotic lichen planus than in patients with the atrophic and erosive forms (P = 0.0008). In the inflammatory cells, the expression of MT was inversely correlated with increasing age (R = 0.34, P = 0.0069). The pattern of expression of MT and caspase-2 in OLP suggests an extensive antiapoptotic response in the keratotic form of the disease. Symptomatic patients may benefit from therapy targeted to apoptosis in the future. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A large complement of the predicted Arabidopsis ARM repeat proteins are members of the U-box E3 ubiquitin ligase family.

PubMed

Mudgil, Yashwanti; Shiu, Shin-Han; Stone, Sophia L; Salt, Jennifer N; Goring, Daphne R

2004-01-01

The Arabidopsis genome was searched to identify predicted proteins containing armadillo (ARM) repeats, a motif known to mediate protein-protein interactions in a number of different animal proteins. Using domain database predictions and models generated in this study, 108 Arabidopsis proteins were identified that contained a minimum of two ARM repeats with the majority of proteins containing four to eight ARM repeats. Clustering analysis showed that the 108 predicted Arabidopsis ARM repeat proteins could be divided into multiple groups with wide differences in their domain compositions and organizations. Interestingly, 41 of the 108 Arabidopsis ARM repeat proteins contained a U-box, a motif present in a family of E3 ligases, and these proteins represented the largest class of Arabidopsis ARM repeat proteins. In 14 of these U-box/ARM repeat proteins, there was also a novel conserved domain identified in the N-terminal region. Based on the phylogenetic tree, representative U-box/ARM repeat proteins were selected for further study. RNA-blot analyses revealed that these U-box/ARM proteins are expressed in a variety of tissues in Arabidopsis. In addition, the selected U-box/ARM proteins were found to be functional E3 ubiquitin ligases. Thus, these U-box/ARM proteins represent a new family of E3 ligases in Arabidopsis.

Differential expression of members of the annexin multigene family in Arabidopsis

NASA Technical Reports Server (NTRS)

Clark, G. B.; Sessions, A.; Eastburn, D. J.; Roux, S. J.

2001-01-01

Although in most plant species no more than two annexin genes have been reported to date, seven annexin homologs have been identified in Arabidopsis, Annexin Arabidopsis 1-7 (AnnAt1--AnnAt7). This establishes that annexins can be a diverse, multigene protein family in a single plant species. Here we compare and analyze these seven annexin gene sequences and present the in situ RNA localization patterns of two of these genes, AnnAt1 and AnnAt2, during different stages of Arabidopsis development. Sequence analysis of AnnAt1--AnnAt7 reveals that they contain the characteristic four structural repeats including the more highly conserved 17-amino acid endonexin fold region found in vertebrate annexins. Alignment comparisons show that there are differences within the repeat regions that may have functional importance. To assess the relative level of expression in various tissues, reverse transcription-PCR was carried out using gene-specific primers for each of the Arabidopsis annexin genes. In addition, northern blot analysis using gene-specific probes indicates differences in AnnAt1 and AnnAt2 expression levels in different tissues. AnnAt1 is expressed in all tissues examined and is most abundant in stems, whereas AnnAt2 is expressed mainly in root tissue and to a lesser extent in stems and flowers. In situ RNA localization demonstrates that these two annexin genes display developmentally regulated tissue-specific and cell-specific expression patterns. These patterns are both distinct and overlapping. The developmental expression patterns for both annexins provide further support for the hypothesis that annexins are involved in the Golgi-mediated secretion of polysaccharides.

Genome-Wide Analysis of the Arabidopsis Replication Timing Program1[OPEN

PubMed Central

Brooks, Ashley M.; Wheeler, Emily; LeBlanc, Chantal; Lee, Tae-Jin; Martienssen, Robert A.; Thompson, William F.

2018-01-01

Eukaryotes use a temporally regulated process, known as the replication timing program, to ensure that their genomes are fully and accurately duplicated during S phase. Replication timing programs are predictive of genomic features and activity and are considered to be functional readouts of chromatin organization. Although replication timing programs have been described for yeast and animal systems, much less is known about the temporal regulation of plant DNA replication or its relationship to genome sequence and chromatin structure. We used the thymidine analog, 5-ethynyl-2′-deoxyuridine, in combination with flow sorting and Repli-Seq to describe, at high-resolution, the genome-wide replication timing program for Arabidopsis (Arabidopsis thaliana) Col-0 suspension cells. We identified genomic regions that replicate predominantly during early, mid, and late S phase, and correlated these regions with genomic features and with data for chromatin state, accessibility, and long-distance interaction. Arabidopsis chromosome arms tend to replicate early while pericentromeric regions replicate late. Early and mid-replicating regions are gene-rich and predominantly euchromatic, while late regions are rich in transposable elements and primarily heterochromatic. However, the distribution of chromatin states across the different times is complex, with each replication time corresponding to a mixture of states. Early and mid-replicating sequences interact with each other and not with late sequences, but early regions are more accessible than mid regions. The replication timing program in Arabidopsis reflects a bipartite genomic organization with early/mid-replicating regions and late regions forming separate, noninteracting compartments. The temporal order of DNA replication within the early/mid compartment may be modulated largely by chromatin accessibility. PMID:29301956

Physiological genomics of response to soil drying in diverse Arabidopsis accessions.

PubMed

Des Marais, David L; McKay, John K; Richards, James H; Sen, Saunak; Wayne, Tierney; Juenger, Thomas E

2012-03-01

Arabidopsis thaliana, like many species, is characterized by abundant genetic variation. This variation is rapidly being cataloged at the sequence level, but careful dissection of genetic variation in whole-organism responses to stresses encountered in the natural environment are lacking; this functional variation can be exploited as a natural mutant screen to determine gene function. Here, we document physiological and transcriptomic response to soil drying in 17 natural accessions of Arabidopsis. By imposing ecologically realistic stress conditions, we found that acclimation in Arabidopsis involved a strong signature of increased investment in photosynthesis, carbohydrate turnover, and root growth. Our results extend previous work in the Columbia accession suggesting that abscisic acid signaling pathways play an important role in drought stress response. We also identified several mechanisms, including an increase in leaf nitrogen concentration and upregulation of two-component signaling relays, that were common to most natural accessions but had not been identified in studies using only the Columbia accession. Principal component analysis reveals strong correlations between suites of genes and specific physiological responses to stress. The functional variants we identified may represent adaptive mutations in natural habitats and useful variants for agronomic improvement of crop species.

Differential Expression of Metallothionein Isoforms in Terrestrial Snail Embryos Reflects Early Life Stage Adaptation to Metal Stress

PubMed Central

Baurand, Pierre-Emmanuel; Pedrini-Martha, Veronika; de Vaufleury, Annette; Niederwanger, Michael; Capelli, Nicolas; Scheifler, Renaud; Dallinger, Reinhard

2015-01-01

The aim of this study was to analyze the expression of three metallothionein (MT) isoform genes (CdMT, CuMT and Cd/CuMT), already known from adults, in the Early Life Stage (ELS) of Cantareus aspersus. This was accomplished by detection of the MT isoform-specific transcription adopting Polymerase Chain Reaction (PCR) amplification and quantitative Real Time (qRT)-PCR of the three MT genes. Freshly laid eggs were kept for 24 hours under control conditions or exposed to three cadmium (Cd) solutions of increasing concentration (5, 10, and 15 mg Cd/L). The transcription of the three MT isoform genes was detected via PCR in 1, 6 and 12-day-old control or Cd-exposed embryos. Moreover, the transcription of this isoform genes during development was followed by qRT-PCR in 6 and 12-day-old embryos. Our results showed that the CdMT and Cd/CuMT genes, but not the CuMT gene, are expressed in embryos at the first day of development. The transcription of the 3 MT genes in control embryos increased with development time, suggesting that the capacities of metal regulation and detoxification may have gradually increased throughout embryogenesis. However in control embryos, the most highly expressed MT gene was that of the Cd/CuMT isoform, whose transcription levels greatly exceeded those of the other two MT genes. This contrasts with the minor significance of this gene in adult snails and suggests that in embryos, this isoform may play a comparatively more important role in metal physiology compared to adult individuals. This function in adult snails appears not to be related to Cd detoxification. Instead, snail embryos responded to Cd exposure by over-expression of the CdMT gene in a concentration-dependent manner, whereas the expression of the Cd/CuMT gene remained unaffected. Moreover, our study demonstrates the ability of snail embryos to respond very early to Cd exposure by up-regulation of the CdMT gene. PMID:25706953

Analyses of a gravistimulation-specific Ca2+ signature in Arabidopsis using parabolic flights.

PubMed

Toyota, Masatsugu; Furuichi, Takuya; Sokabe, Masahiro; Tatsumi, Hitoshi

2013-10-01

Gravity is a critical environmental factor affecting the morphology and functions of organisms on the Earth. Plants sense changes in the gravity vector (gravistimulation) and regulate their growth direction accordingly. In Arabidopsis (Arabidopsis thaliana) seedlings, gravistimulation, achieved by rotating the specimens under the ambient 1g of the Earth, is known to induce a biphasic (transient and sustained) increase in cytoplasmic calcium concentration ([Ca(2+)]c). However, the [Ca(2+)]c increase genuinely caused by gravistimulation has not been identified because gravistimulation is generally accompanied by rotation of specimens on the ground (1g), adding an additional mechanical signal to the treatment. Here, we demonstrate a gravistimulation-specific Ca(2+) response in Arabidopsis seedlings by separating rotation from gravistimulation by using the microgravity (less than 10(-4)g) conditions provided by parabolic flights. Gravistimulation without rotating the specimen caused a sustained [Ca(2+)]c increase, which corresponds closely to the second sustained [Ca(2+)]c increase observed in ground experiments. The [Ca(2+)]c increases were analyzed under a variety of gravity intensities (e.g. 0.5g, 1.5g, or 2g) combined with rapid switching between hypergravity and microgravity, demonstrating that Arabidopsis seedlings possess a very rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes (0.5g-2g) into Ca(2+) signals on a subsecond time scale.

Comparative interactomics: analysis of arabidopsis 14-3-3 complexes reveals highly conserved 14-3-3 interactions between humans and plants.

PubMed

Paul, Anna-Lisa; Liu, Li; McClung, Scott; Laughner, Beth; Chen, Sixue; Ferl, Robert J

2009-04-01

As a first step in the broad characterization of plant 14-3-3 multiprotein complexes in vivo, stringent and specific antibody affinity purification was used to capture 14-3-3s together with their interacting proteins from extracts of Arabidopsis cell suspension cultures. Approximately 120 proteins were identified as potential in vivo 14-3-3 interacting proteins by mass spectrometry of the recovered complexes. Comparison of the proteins in this data set with the 14-3-3 interacting proteins from a similar study in human embryonic kidney cell cultures revealed eight interacting proteins that likely represent reasonably abundant, fundamental 14-3-3 interaction complexes that are highly conserved across all eukaryotes. The Arabidopsis 14-3-3 interaction data set was also compared to a yeast in vivo 14-3-3 interaction data set. Four 14-3-3 interacting proteins are conserved in yeast, humans, and Arabidopsis. Comparisons of the data sets based on biochemical function revealed many additional similarities in the human and Arabidopsis data sets that represent conserved functional interactions, while also leaving many proteins uniquely identified in either Arabidopsis or human cells. In particular, the Arabidopsis interaction data set is enriched for proteins involved in metabolism.

Rapid accumulation of glutathione during light stress in Arabidopsis.

PubMed

Choudhury, Feroza K; Devireddy, Amith R; Azad, Rajeev K; Shulaev, Vladimir; Mittler, Ron

2018-05-25

Environmental stress conditions can drastically affect plant growth and productivity. In contrast to soil moisture or salinity that can gradually change over a period of days or weeks, changes in light intensity or temperature can occur very rapidly, sometimes over the course of minutes or seconds. We previously reported that in response to rapid changes in light intensity (0-60 sec), Arabidopsis thaliana plants mount a large-scale transcriptomic response that includes several different transcripts essential for light stress acclimation. Here, we expand our analysis of the rapid response of Arabidopsis to light stress using a metabolomics approach and identify 111 metabolites that significantly alter in their level during the first 90 sec of light stress exposure. We further show that the levels of free and total glutathione accumulate rapidly during light stress in Arabidopsis and that the accumulation of total glutathione during light stress is associated with an increase in nitric oxide (NO) levels. We further suggest that the increase in precursors for glutathione biosynthesis could be linked to alterations in photorespiration, and that phosphoenolpyruvate could represent a major energy and carbon source for rapid metabolic responses. Taken together, our analysis could be used as an initial road map for the identification of different pathways that could be used to augment the rapid response of plants to abiotic stress. In addition, it highlights the important role of glutathione in these responses.

The translational landscape of Arabidopsis mitochondria.

PubMed

Planchard, Noelya; Bertin, Pierre; Quadrado, Martine; Dargel-Graffin, Céline; Hatin, Isabelle; Namy, Olivier; Mireau, Hakim

2018-06-05

Messenger RNA translation is a complex process that is still poorly understood in eukaryotic organelles like mitochondria. Growing evidence indicates though that mitochondrial translation differs from its bacterial counterpart in many key aspects. In this analysis, we have used ribosome profiling technology to generate a genome-wide snapshot view of mitochondrial translation in Arabidopsis. We show that, unlike in humans, most Arabidopsis mitochondrial ribosome footprints measure 27 and 28 bases. We also reveal that respiratory subunits encoding mRNAs show much higher ribosome association than other mitochondrial mRNAs, implying that they are translated at higher levels. Homogenous ribosome densities were generally detected within each respiratory complex except for complex V, where higher ribosome coverage corroborated with higher requirements for specific subunits. In complex I respiratory mutants, a reorganization of mitochondrial mRNAs ribosome association was detected involving increased ribosome densities for certain ribosomal protein encoding transcripts and a reduction in translation of a few complex V mRNAs. Taken together, our observations reveal that plant mitochondrial translation is a dynamic process and that translational control is important for gene expression in plant mitochondria. This study paves the way for future advances in the understanding translation in higher plant mitochondria.

Azospirillum brasilense ameliorates the response of Arabidopsis thaliana to drought mainly via enhancement of ABA levels.

PubMed

Cohen, Ana C; Bottini, Rubén; Pontin, Mariela; Berli, Federico J; Moreno, Daniela; Boccanlandro, Hernán; Travaglia, Claudia N; Piccoli, Patricia N

2015-01-01

Production of phytohormones is one of the main mechanisms to explain the beneficial effects of plant growth-promoting rhizobacteria (PGPR) such as Azospirillum sp. The PGPRs induce plant growth and development, and reduce stress susceptibility. However, little is known regarding the stress-related phytohormone abscisic acid (ABA) produced by bacteria. We investigated the effects of Azospirillum brasilense Sp 245 strain on Arabidopsis thaliana Col-0 and aba2-1 mutant plants, evaluating the morphophysiological and biochemical responses when watered and in drought. We used an in vitro-grown system to study changes in the root volume and architecture after inoculation with Azospirillum in Arabidopsis wild-type Col-0 and on the mutant aba2-1, during early growth. To examine Arabidopsis development and reproductive success as affected by the bacteria, ABA and drought, a pot experiment using Arabidopsis Col-0 plants was also carried out. Azospirillum brasilense augmented plant biomass, altered root architecture by increasing lateral roots number, stimulated photosynthetic and photoprotective pigments and retarded water loss in correlation with incremented ABA levels. As well, inoculation improved plants seed yield, plants survival, proline levels and relative leaf water content; it also decreased stomatal conductance, malondialdehyde and relative soil water content in plants submitted to drought. Arabidopsis inoculation with A. brasilense improved plants performance, especially in drought. © 2014 Scandinavian Plant Physiology Society.

Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

DOE PAGES

Wang, Wei; Li, Eryang; Porth, Ilga; ...

2016-02-02

Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter,more » PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.« less

Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei; Li, Eryang; Porth, Ilga

Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter,more » PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.« less

Diversity of the Arabidopsis mitochondrial genome occurs via nuclear-controlled recombination activity.

PubMed

Arrieta-Montiel, Maria P; Shedge, Vikas; Davila, Jaime; Christensen, Alan C; Mackenzie, Sally A

2009-12-01

The plant mitochondrial genome is recombinogenic, with DNA exchange activity controlled to a large extent by nuclear gene products. One nuclear gene, MSH1, appears to participate in suppressing recombination in Arabidopsis at every repeated sequence ranging in size from 108 to 556 bp. Present in a wide range of plant species, these mitochondrial repeats display evidence of successful asymmetric DNA exchange in Arabidopsis when MSH1 is disrupted. Recombination frequency appears to be influenced by repeat sequence homology and size, with larger size repeats corresponding to increased DNA exchange activity. The extensive mitochondrial genomic reorganization of the msh1 mutant produced altered mitochondrial transcription patterns. Comparison of mitochondrial genomes from the Arabidopsis ecotypes C24, Col-0, and Ler suggests that MSH1 activity accounts for most or all of the polymorphisms distinguishing these genomes, producing ecotype-specific stoichiometric changes in each line. Our observations suggest that MSH1 participates in mitochondrial genome evolution by influencing the lineage-specific pattern of mitochondrial genetic variation in higher plants.

AtmiRNET: a web-based resource for reconstructing regulatory networks of Arabidopsis microRNAs.

PubMed

Chien, Chia-Hung; Chiang-Hsieh, Yi-Fan; Chen, Yi-An; Chow, Chi-Nga; Wu, Nai-Yun; Hou, Ping-Fu; Chang, Wen-Chi

2015-01-01

Compared with animal microRNAs (miRNAs), our limited knowledge of how miRNAs involve in significant biological processes in plants is still unclear. AtmiRNET is a novel resource geared toward plant scientists for reconstructing regulatory networks of Arabidopsis miRNAs. By means of highlighted miRNA studies in target recognition, functional enrichment of target genes, promoter identification and detection of cis- and trans-elements, AtmiRNET allows users to explore mechanisms of transcriptional regulation and miRNA functions in Arabidopsis thaliana, which are rarely investigated so far. High-throughput next-generation sequencing datasets from transcriptional start sites (TSSs)-relevant experiments as well as five core promoter elements were collected to establish the support vector machine-based prediction model for Arabidopsis miRNA TSSs. Then, high-confidence transcription factors participate in transcriptional regulation of Arabidopsis miRNAs are provided based on statistical approach. Furthermore, both experimentally verified and putative miRNA-target interactions, whose validity was supported by the correlations between the expression levels of miRNAs and their targets, are elucidated for functional enrichment analysis. The inferred regulatory networks give users an intuitive insight into the pivotal roles of Arabidopsis miRNAs through the crosstalk between miRNA transcriptional regulation (upstream) and miRNA-mediate (downstream) gene circuits. The valuable information that is visually oriented in AtmiRNET recruits the scant understanding of plant miRNAs and will be useful (e.g. ABA-miR167c-auxin signaling pathway) for further research. Database URL: http://AtmiRNET.itps.ncku.edu.tw/ © The Author(s) 2015. Published by Oxford University Press.

The COP9 signalosome interacts with SCF UFO and participates in Arabidopsis flower development.

PubMed

Wang, Xiping; Feng, Suhua; Nakayama, Naomi; Crosby, W L; Irish, Vivian; Deng, Xing Wang; Wei, Ning

2003-05-01

The COP9 signalosome (CSN) is involved in multiple developmental processes. It interacts with SCF ubiquitin ligases and deconjugates Nedd8/Rub1 from cullins (deneddylation). CSN is highly expressed in Arabidopsis floral tissues. To investigate the role of CSN in flower development, we examined the expression pattern of CSN in developing flowers. We report here that two csn1 partially deficient Arabidopsis strains exhibit aberrant development of floral organs, decline of APETALA3 (AP3) expression, and low fertility in addition to defects in shoot and inflorescence meristems. We show that UNUSUAL FLORAL ORGANS (UFO) forms a SCF(UFO) complex, which is associated with CSN in vivo. Genetic interaction analysis indicates that CSN is necessary for the gain-of-function activity of the F-box protein UFO in AP3 activation and in floral organ transformation. Compared with the previously reported csn5 antisense and csn1 null mutants, partial deficiency of CSN1 causes a reduction in the level of CUL1 in the mutant flowers without an obvious defect in CUL1 deneddylation. We conclude that CSN is an essential regulator of Arabidopsis flower development and suggest that CSN regulates Arabidopsis flower development in part by modulating SCF(UFO)-mediated AP3 activation.

Membrane-localized ubiquitin ligase ATL15 functions in sugar-responsive growth regulation in Arabidopsis.

PubMed

Aoyama, Shoki; Terada, Saki; Sanagi, Miho; Hasegawa, Yoko; Lu, Yu; Morita, Yoshie; Chiba, Yukako; Sato, Takeo; Yamaguchi, Junji

2017-09-09

Ubiquitin ligases play important roles in regulating various cellular processes by modulating the protein function of specific ubiquitination targets. The Arabidopsis Tóxicos en Levadura (ATL) family is a group of plant-specific RING-type ubiquitin ligases that localize to membranes via their N-terminal transmembrane-like domains. To date, 91 ATL isoforms have been identified in the Arabidopsis genome, with several ATLs reported to be involved in regulating plant responses to environmental stresses. However, the functions of most ATLs remain unknown. This study, involving transcriptome database analysis, identifies ATL15 as a sugar responsive ATL gene in Arabidopsis. ATL15 expression was rapidly down-regulated in the presence of sugar. The ATL15 protein showed ubiquitin ligase activity in vitro and localized to plasma membrane and endomembrane compartments. Further genetic analyses demonstrated that the atl15 knockout mutants are insensitive to high glucose concentrations, whereas ATL15 overexpression depresses plant growth. In addition, endogenous glucose and starch amounts were reciprocally affected in the atl15 knockout mutants and the ATL15 overexpressors. These results suggest that ATL15 protein plays a significant role as a membrane-localized ubiquitin ligase that regulates sugar-responsive plant growth in Arabidopsis. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of a Direct Headspace Collection Method from Arabidopsis Seedlings Using HS-SPME-GC-TOF-MS Analysis

PubMed Central

Kusano, Miyako; Iizuka, Yumiko; Kobayashi, Makoto; Fukushima, Atsushi; Saito, Kazuki

2013-01-01

Plants produce various volatile organic compounds (VOCs), which are thought to be a crucial factor in their interactions with harmful insects, plants and animals. Composition of VOCs may differ when plants are grown under different nutrient conditions, i.e., macronutrient-deficient conditions. However, in plants, relationships between macronutrient assimilation and VOC composition remain unclear. In order to identify the kinds of VOCs that can be emitted when plants are grown under various environmental conditions, we established a conventional method for VOC profiling in Arabidopsis thaliana (Arabidopsis) involving headspace-solid-phase microextraction-gas chromatography-time-of-flight-mass spectrometry (HS-SPME-GC-TOF-MS). We grew Arabidopsis seedlings in an HS vial to directly perform HS analysis. To maximize the analytical performance of VOCs, we optimized the extraction method and the analytical conditions of HP-SPME-GC-TOF-MS. Using the optimized method, we conducted VOC profiling of Arabidopsis seedlings, which were grown under two different nutrition conditions, nutrition-rich and nutrition-deficient conditions. The VOC profiles clearly showed a distinct pattern with respect to each condition. This study suggests that HS-SPME-GC-TOF-MS analysis has immense potential to detect changes in the levels of VOCs in not only Arabidopsis, but other plants grown under various environmental conditions. PMID:24957989

The cysteine2/histidine2-type transcription factor ZINC FINGER OF ARABIDOPSIS THALIANA 6-activated C-REPEAT-BINDING FACTOR pathway is essential for melatonin-mediated freezing stress resistance in Arabidopsis.

PubMed

Shi, Haitao; Chan, Zhulong

2014-09-01

Melatonin (N-acetyl-5-methoxytryptamine) is not only a widely known animal hormone, but also an important regulator in plant development and multiple abiotic stress responses. Recently, it has been revealed that melatonin alleviated cold stress through mediating several cold-related genes, including C-REPEAT-BINDING FACTORs (CBFs)/Drought Response Element Binding factors (DREBs), COR15a, and three transcription factors (CAMTA1, ZINC FINGER OF ARABIDOPSIS THALIANA 10 (ZAT10), and ZAT12). In this study, we quantified the endogenous melatonin level in Arabidopsis plant leaves and found the endogenous melatonin levels were significantly induced by cold stress (4 °C) treatment. In addition, we found one cysteine2/histidine2-type zinc finger transcription factor, ZAT6, was involved in melatonin-mediated freezing stress response in Arabidopsis. Interestingly, exogenous melatonin enhanced freezing stress resistance was largely alleviated in AtZAT6 knockdown plants, but was enhanced in AtZAT6 overexpressing plants. Moreover, the expression levels of AtZAT6 and AtCBFs were commonly upregulated by cold stress (4 °C) and exogenous melatonin treatments, and modulation of AtZAT6 expression significantly affected the induction AtCBFs transcripts by cold stress (4 °C) and exogenous melatonin treatments. Taken together, AtZAT6-activated CBF pathway might be essential for melatonin-mediated freezing stress response in Arabidopsis. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Purification of a Jojoba Embryo Wax Synthase, Cloning of its cDNA, and Production of High Levels of Wax in Seeds of Transgenic Arabidopsis

PubMed Central

Lardizabal, Kathryn D.; Metz, James G.; Sakamoto, Tetsuo; Hutton, William C.; Pollard, Michael R.; Lassner, Michael W.

2000-01-01

Wax synthase (WS, fatty acyl-coenzyme A [coA]: fatty alcohol acyltransferase) catalyzes the final step in the synthesis of linear esters (waxes) that accumulate in seeds of jojoba (Simmondsia chinensis). We have characterized and partially purified this enzyme from developing jojoba embryos. A protein whose presence correlated with WS activity during chromatographic fractionation was identified and a cDNA encoding that protein was cloned. Seed-specific expression of the cDNA in transgenic Arabidopsis conferred high levels of WS activity on developing embryos from those plants. The WS sequence has significant homology with several Arabidopsis open reading frames of unknown function. Wax production in jojoba requires, in addition to WS, a fatty acyl-CoA reductase (FAR) and an efficient fatty acid elongase system that forms the substrates preferred by the FAR. We have expressed the jojoba WS cDNA in Arabidopsis in combination with cDNAs encoding the jojoba FAR and a β-ketoacyl-CoA synthase (a component of fatty acid elongase) from Lunaria annua. 13C-Nuclear magnetic resonance analysis of pooled whole seeds from transgenic plants indicated that as many as 49% of the oil molecules in the seeds were waxes. Gas chromatography analysis of transmethylated oil from individual seeds suggested that wax levels may represent up to 70% (by weight) of the oil present in those seeds. PMID:10712527

Purification of a jojoba embryo wax synthase, cloning of its cDNA, and production of high levels of wax in seeds of transgenic arabidopsis.

PubMed

Lardizabal, K D; Metz, J G; Sakamoto, T; Hutton, W C; Pollard, M R; Lassner, M W

2000-03-01

Wax synthase (WS, fatty acyl-coenzyme A [coA]: fatty alcohol acyltransferase) catalyzes the final step in the synthesis of linear esters (waxes) that accumulate in seeds of jojoba (Simmondsia chinensis). We have characterized and partially purified this enzyme from developing jojoba embryos. A protein whose presence correlated with WS activity during chromatographic fractionation was identified and a cDNA encoding that protein was cloned. Seed-specific expression of the cDNA in transgenic Arabidopsis conferred high levels of WS activity on developing embryos from those plants. The WS sequence has significant homology with several Arabidopsis open reading frames of unknown function. Wax production in jojoba requires, in addition to WS, a fatty acyl-CoA reductase (FAR) and an efficient fatty acid elongase system that forms the substrates preferred by the FAR. We have expressed the jojoba WS cDNA in Arabidopsis in combination with cDNAs encoding the jojoba FAR and a beta-ketoacyl-CoA synthase (a component of fatty acid elongase) from Lunaria annua. (13)C-Nuclear magnetic resonance analysis of pooled whole seeds from transgenic plants indicated that as many as 49% of the oil molecules in the seeds were waxes. Gas chromatography analysis of transmethylated oil from individual seeds suggested that wax levels may represent up to 70% (by weight) of the oil present in those seeds.

A transgene design for enhancing oil content in Arabidopsis and Camelina seeds

DOE PAGES

Zhu, Yerong; Xie, Linan; Chen, Grace Q.; ...

2018-02-21

Background: Increasing the oil yield is a major objective for oilseed crop improvement. Oil biosynthesis and accumulation are influenced by multiple genes involved in embryo and seed development. The leafy cotyledon1 (LEC1) is a master regulator of embryo development that also enhances the expression of genes involved in fatty acid biosynthesis. We speculated that seed oil could be increased by targeted overexpression of a master regulating transcription factor for oil biosynthesis, using a downstream promoter for a gene in the oil biosynthesis pathway. To verify the effect of such a combination on seed oil content, we made constructs with maizemore » (Zea mays) ZmLEC1 driven by serine carboxypeptidase-like (SCPL17) and acyl carrier protein (ACP5) promoters, respectively, for expression in transgenic Arabidopsis thaliana and Camelina sativa. Results: Agrobacterium-mediated transformation successfully generated Arabidopsis and Camelina lines that overexpressed ZmLEC1 under the control of a seed-specific promoter. This overexpression does not appear to be detrimental to seed vigor under laboratory conditions and did not cause observable abnormal growth phenotypes throughout the life cycle of the plants. Overexpression of ZmLEC1 increased the oil content in mature seeds by more than 20% in Arabidopsis and 26% in Camelina. In conclusion: The findings suggested that the maize master regulator, ZmLEC1, driven by a downstream seed-specific promoter, can be used to increase oil production in Arabidopsis and Camelina and might be a promising target for increasing oil yield in oilseed crops.0« less

Host and non-host pathogens elicit different jasmonate/ethylene responses in Arabidopsis.

PubMed

Zimmerli, Laurent; Stein, Mónica; Lipka, Volker; Schulze-Lefert, Paul; Somerville, Shauna

2004-12-01

Arabidopsis does not support the growth and asexual reproduction of the barley pathogen, Blumeria graminis f. sp. hordei Bgh). A majority of germlings fail to penetrate the epidermal cell wall and papillae. To gain additional insight into this interaction, we determined whether the salicylic acid (SA) or jasmonate (JA)/ethylene (ET) defence pathways played a role in blocking barley powdery mildew infections. Only the eds1 mutant and NahG transgenics supported a modest increase in penetration success by the barley powdery mildew. We also compared the global gene expression patterns of Arabidopsis inoculated with the non-host barley powdery mildew to those inoculated with a virulent, host powdery mildew, Erysiphe cichoracearum. Genes repressed by inoculations with non-host and host powdery mildews relative to non-inoculated control plants accounted for two-thirds of the differentially expressed genes. A majority of these genes encoded components of photosynthesis and general metabolism. Consistent with this observation, Arabidopsis growth was inhibited following inoculation with Bgh, suggesting a shift in resource allocation from growth to defence. A number of defence-associated genes were induced during both interactions. These genes likely are components of basal defence responses, which do not effectively block host powdery mildew infections. In addition, genes encoding defensins, anti-microbial peptides whose expression is under the control of the JA/ET signalling pathway, were induced exclusively by non-host pathogens. Ectopic activation of JA/ET signalling protected Arabidopsis against two biotrophic host pathogens. Taken together, these data suggest that biotrophic host pathogens must either suppress or fail to elicit the JA/ET signal transduction pathway.

A transgene design for enhancing oil content in Arabidopsis and Camelina seeds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Yerong; Xie, Linan; Chen, Grace Q.

Background: Increasing the oil yield is a major objective for oilseed crop improvement. Oil biosynthesis and accumulation are influenced by multiple genes involved in embryo and seed development. The leafy cotyledon1 (LEC1) is a master regulator of embryo development that also enhances the expression of genes involved in fatty acid biosynthesis. We speculated that seed oil could be increased by targeted overexpression of a master regulating transcription factor for oil biosynthesis, using a downstream promoter for a gene in the oil biosynthesis pathway. To verify the effect of such a combination on seed oil content, we made constructs with maizemore » (Zea mays) ZmLEC1 driven by serine carboxypeptidase-like (SCPL17) and acyl carrier protein (ACP5) promoters, respectively, for expression in transgenic Arabidopsis thaliana and Camelina sativa. Results: Agrobacterium-mediated transformation successfully generated Arabidopsis and Camelina lines that overexpressed ZmLEC1 under the control of a seed-specific promoter. This overexpression does not appear to be detrimental to seed vigor under laboratory conditions and did not cause observable abnormal growth phenotypes throughout the life cycle of the plants. Overexpression of ZmLEC1 increased the oil content in mature seeds by more than 20% in Arabidopsis and 26% in Camelina. In conclusion: The findings suggested that the maize master regulator, ZmLEC1, driven by a downstream seed-specific promoter, can be used to increase oil production in Arabidopsis and Camelina and might be a promising target for increasing oil yield in oilseed crops.0« less

Biosynthesis of Lipoic Acid in Arabidopsis: Cloning and Characterization of the cDNA for Lipoic Acid Synthase1

PubMed Central

Yasuno, Rie; Wada, Hajime

1998-01-01

Lipoic acid is a coenzyme that is essential for the activity of enzyme complexes such as those of pyruvate dehydrogenase and glycine decarboxylase. We report here the isolation and characterization of LIP1 cDNA for lipoic acid synthase of Arabidopsis. The Arabidopsis LIP1 cDNA was isolated using an expressed sequence tag homologous to the lipoic acid synthase of Escherichia coli. This cDNA was shown to code for Arabidopsis lipoic acid synthase by its ability to complement a lipA mutant of E. coli defective in lipoic acid synthase. DNA-sequence analysis of the LIP1 cDNA revealed an open reading frame predicting a protein of 374 amino acids. Comparisons of the deduced amino acid sequence with those of E. coli and yeast lipoic acid synthase homologs showed a high degree of sequence similarity and the presence of a leader sequence presumably required for import into the mitochondria. Southern-hybridization analysis suggested that LIP1 is a single-copy gene in Arabidopsis. Western analysis with an antibody against lipoic acid synthase demonstrated that this enzyme is located in the mitochondrial compartment in Arabidopsis cells as a 43-kD polypeptide. PMID:9808738

Arabidopsis: an adequate model for dicot root systems

USDA-ARS?s Scientific Manuscript database

In the search for answers to pressing root developmental genetic issues, plant science has turned to a small genome dicot plant (Arabidopsis) to be used as a model to study and use to develop hypotheses for testing other species. Through out the published research only three classes of root are des...

Two Closely Related Genes of Arabidopsis Encode Plastidial Cytidinediphosphate Diacylglycerol Synthases Essential for Photoautotrophic Growth1[C

PubMed Central

Haselier, André; Akbari, Hana; Weth, Agnes; Baumgartner, Werner; Frentzen, Margrit

2010-01-01

Cytidinediphosphate diacylglycerol synthase (CDS) catalyzes the formation of cytidinediphosphate diacylglycerol, an essential precursor of anionic phosphoglycerolipids like phosphatidylglycerol or -inositol. In plant cells, CDS isozymes are located in plastids, mitochondria, and microsomes. Here, we show that these isozymes are encoded by five genes in Arabidopsis (Arabidopsis thaliana). Alternative translation initiation or alternative splicing of CDS2 and CDS4 transcripts can result in up to 10 isoforms. Most of the cDNAs encoding the various plant isoforms were functionally expressed in yeast and rescued the nonviable phenotype of the mutant strain lacking CDS activity. The closely related genes CDS4 and CDS5 were found to encode plastidial isozymes with similar catalytic properties. Inactivation of both genes was required to obtain Arabidopsis mutant lines with a visible phenotype, suggesting that the genes have redundant functions. Analysis of these Arabidopsis mutants provided further independent evidence for the importance of plastidial phosphatidylglycerol for structure and function of thylakoid membranes and, hence, for photoautotrophic growth. PMID:20442275

Arabidopsis Seed Content QTL Mapping Using High-Throughput Phenotyping: The Assets of Near Infrared Spectroscopy

PubMed Central

Jasinski, Sophie; Lécureuil, Alain; Durandet, Monique; Bernard-Moulin, Patrick; Guerche, Philippe

2016-01-01

Seed storage compounds are of crucial importance for human diet, feed and industrial uses. In oleo-proteaginous species like rapeseed, seed oil and protein are the qualitative determinants that conferred economic value to the harvested seed. To date, although the biosynthesis pathways of oil and storage protein are rather well-known, the factors that determine how these types of reserves are partitioned in seeds have to be identified. With the aim of implementing a quantitative genetics approach, requiring phenotyping of 100s of plants, our first objective was to establish near-infrared reflectance spectroscopic (NIRS) predictive equations in order to estimate oil, protein, carbon, and nitrogen content in Arabidopsis seed with high-throughput level. Our results demonstrated that NIRS is a powerful non-destructive, high-throughput method to assess the content of these four major components studied in Arabidopsis seed. With this tool in hand, we analyzed Arabidopsis natural variation for these four components and illustrated that they all displayed a wide range of variation. Finally, NIRS was used in order to map QTL for these four traits using seeds from the Arabidopsis thaliana Ct-1 × Col-0 recombinant inbred line population. Some QTL co-localized with QTL previously identified, but others mapped to chromosomal regions never identified so far for such traits. This paper illustrates the usefulness of NIRS predictive equations to perform accurate high-throughput phenotyping of Arabidopsis seed content, opening new perspectives in gene identification following QTL mapping and genome wide association studies. PMID:27891138

Thermal energy dissipation and xanthophyll cycles beyond the Arabidopsis model.

PubMed

García-Plazaola, José Ignacio; Esteban, Raquel; Fernández-Marín, Beatriz; Kranner, Ilse; Porcar-Castell, Albert

2012-09-01

Thermal dissipation of excitation energy is a fundamental photoprotection mechanism in plants. Thermal energy dissipation is frequently estimated using the quenching of the chlorophyll fluorescence signal, termed non-photochemical quenching. Over the last two decades, great progress has been made in the understanding of the mechanism of thermal energy dissipation through the use of a few model plants, mainly Arabidopsis. Nonetheless, an emerging number of studies suggest that this model represents only one strategy among several different solutions for the environmental adjustment of thermal energy dissipation that have evolved among photosynthetic organisms in the course of evolution. In this review, a detailed analysis of three examples highlights the need to use models other than Arabidopsis: first, overwintering evergreens that develop a sustained form of thermal energy dissipation; second, desiccation tolerant plants that induce rapid thermal energy dissipation; and third, understorey plants in which a complementary lutein epoxide cycle modulates thermal energy dissipation. The three examples have in common a shift from a photosynthetically efficient state to a dissipative conformation, a strategy widely distributed among stress-tolerant evergreen perennials. Likewise, they show a distinct operation of the xanthophyll cycle. Expanding the list of model species beyond Arabidopsis will enhance our knowledge of these mechanisms and increase the synergy of the current studies now dispersed over a wide number of species.

Genetic Analysis of Growth-Regulator-Induced Parthenocarpy in Arabidopsis1

PubMed Central

Vivian-Smith, Adam; Koltunow, Anna M.

1999-01-01

In Arabidopsis, seedless silique development or parthenocarpy can be induced by the application of various plant growth regulators (PGRs) to unfertilized pistils. Ecotype-specific responses were observed in the Arabidopsis ecotypes Columbia and Landsberg relative to the type of PGR and level applied. The parthenocarpic response was greatest in ecotype Landsberg, and comparisons of fruit growth and morphology were studied primarily in this ecotype. Gibberellic acid application (10 μmol pistil−1) caused development similar to that in pollinated pistils, while benzyladenine (1 μmol pistil−1) and naphthylacetic acid (10 μmol pistil−1) treatment produced shorter siliques. Naphthylacetic acid primarily modified mesocarp cell expansion. Arabidopsis mutants were employed to examine potential dependencies on gibberellin biosynthesis (ga1-3, ga4-1, and ga5-1) and perception (spy-4 and gai) during parthenocarpic silique development. Emasculated spy-4 pistils were neither obviously parthenocarpic nor deficient in PGR perception. By contrast, emasculated gai mutants did not produce parthenocarpic siliques following gibberellic acid application, but silique development occurred following pollination or application of auxin and cytokinin. Pollinated gai siliques had decreased cell numbers and morphologically resembled auxin-induced parthenocarpic siliques. This shows that a number of independent and possibly redundant pathways can direct hormone-induced parthenocarpy, and that endogenous gibberellins play a role in regulating cell expansion and promoting cell division in carpels. PMID:10517835

Transcriptomic and lipidomic profiles of glycerolipids during Arabidopsis flower development.

PubMed

Nakamura, Yuki; Teo, Norman Z W; Shui, Guanghou; Chua, Christine H L; Cheong, Wei-Fun; Parameswaran, Sriram; Koizumi, Ryota; Ohta, Hiroyuki; Wenk, Markus R; Ito, Toshiro

2014-07-01

Flower glycerolipids are the yet-to-be discovered frontier of the lipidome. Although ample evidence suggests important roles for glycerolipids in flower development, stage-specific lipid profiling in tiny Arabidopsis flowers is challenging. Here, we utilized a transgenic system to synchronize flower development in Arabidopsis. The transgenic plant PAP1::AP1-GR ap1-1 cal-5 showed synchronized flower development upon dexamethasone treatment, which enabled massive harvesting of floral samples of homogenous developmental stages for glycerolipid profiling. Glycerolipid profiling revealed a decrease in concentrations of phospholipids involved in signaling during the early development stages, such as phosphatidic acid and phosphatidylinositol, and a marked increase in concentrations of nonphosphorous galactolipids during the late stage. Moreover, in the midstage, phosphatidylinositol 4,5-bisphosphate concentration was increased transiently, which suggests the stimulation of the phosphoinositide metabolism. Accompanying transcriptomic profiling of relevant glycerolipid metabolic genes revealed simultaneous induction of multiple phosphoinositide biosynthetic genes associated with the increased phosphatidylinositol 4,5-bisphosphate concentration, with a high degree of differential expression patterns for genes encoding other glycerolipid-metabolic genes. The phosphatidic acid phosphatase mutant pah1 pah2 showed flower developmental defect, suggesting a role for phosphatidic acid in flower development. Our concurrent profiling of glycerolipids and relevant metabolic gene expression revealed distinct metabolic pathways stimulated at different stages of flower development in Arabidopsis. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Priming of the Arabidopsis pattern-triggered immunity response upon infection by necrotrophic Pectobacterium carotovorum bacteria.

PubMed

Po-Wen, Chen; Singh, Prashant; Zimmerli, Laurent

2013-01-01

Boosted responsiveness of plant cells to stress at the onset of pathogen- or chemically induced resistance is called priming. The chemical β-aminobutyric acid (BABA) enhances Arabidopsis thaliana resistance to hemibiotrophic bacteria through the priming of the salicylic acid (SA) defence response. Whether BABA increases Arabidopsis resistance to the necrotrophic bacterium Pectobacterium carotovorum ssp. carotovorum (Pcc) is not clear. In this work, we show that treatment with BABA protects Arabidopsis against the soft-rot pathogen Pcc. BABA did not prime the expression of the jasmonate/ethylene-responsive gene PLANT DEFENSIN 1.2 (PDF1.2), the up-regulation of which is usually associated with resistance to necrotrophic pathogens. Expression of the SA marker gene PATHOGENESIS RELATED 1 (PR1) on Pcc infection was primed by BABA treatment, but SA-defective mutants demonstrated a wild-type level of BABA-induced resistance against Pcc. BABA primed the expression of the pattern-triggered immunity (PTI)-responsive genes FLG22-INDUCED RECEPTOR-LIKE KINASE 1 (FRK1), ARABIDOPSIS NON-RACE SPECIFIC DISEASE RESISTANCE GENE (NDR1)/HAIRPIN-INDUCED GENE (HIN1)-LIKE 10 (NHL10) and CYTOCHROME P450, FAMILY 81 (CYP81F2) after inoculation with Pcc or after treatment with purified bacterial microbe-associated molecular patterns, such as flg22 or elf26. PTI-mediated callose deposition was also potentiated in BABA-treated Arabidopsis, and BABA boosted Arabidopsis stomatal immunity to Pcc. BABA treatment primed the PTI response in the SA-defective mutants SA induction deficient 2-1 (sid2-1) and phytoalexin deficient 4-1 (pad4-1). In addition, BABA priming was associated with open chromatin configurations in the promoter region of PTI marker genes. Our data indicate that BABA primes the PTI response upon necrotrophic bacterial infection and suggest a role for the PTI response in BABA-induced resistance. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

Molecular Characterization of Organelle-Type Nudix Hydrolases in Arabidopsis1[W

PubMed Central

Ogawa, Takahisa; Yoshimura, Kazuya; Miyake, Hiroe; Ishikawa, Kazuya; Ito, Daisuke; Tanabe, Noriaki; Shigeoka, Shigeru

2008-01-01

Nudix (for nucleoside diphosphates linked to some moiety X) hydrolases act to hydrolyze ribonucleoside and deoxyribonucleoside triphosphates, nucleotide sugars, coenzymes, or dinucleoside polyphosphates. Arabidopsis (Arabidopsis thaliana) contains 27 genes encoding Nudix hydrolase homologues (AtNUDX1 to -27) with a predicted distribution in the cytosol, mitochondria, and chloroplasts. Previously, cytosolic Nudix hydrolases (AtNUDX1 to -11 and -25) were characterized. Here, we conducted a characterization of organelle-type AtNUDX proteins (AtNUDX12 to -24, -26, and -27). AtNUDX14 showed pyrophosphohydrolase activity toward both ADP-ribose and ADP-glucose, although its Km value was approximately 100-fold lower for ADP-ribose (13.0 ± 0.7 μm) than for ADP-glucose (1,235 ± 65 μm). AtNUDX15 hydrolyzed not only reduced coenzyme A (118.7 ± 3.4 μm) but also a wide range of its derivatives. AtNUDX19 showed pyrophosphohydrolase activity toward both NADH (335.3 ± 5.4 μm) and NADPH (36.9 ± 3.5 μm). AtNUDX23 had flavin adenine dinucleotide pyrophosphohydrolase activity (9.1 ± 0.9 μm). Both AtNUDX26 and AtNUDX27 hydrolyzed diadenosine polyphosphates (n = 4–5). A confocal microscopic analysis using a green fluorescent protein fusion protein showed that AtNUDX15 is distributed in mitochondria and AtNUDX14 -19, -23, -26, and -27 are distributed in chloroplasts. These AtNUDX mRNAs were detected ubiquitously in various Arabidopsis tissues. The T-DNA insertion mutants of AtNUDX13, -14, -15, -19, -20, -21, -25, -26, and -27 did not exhibit any phenotypical differences under normal growth conditions. These results suggest that Nudix hydrolases in Arabidopsis control a variety of metabolites and are pertinent to a wide range of physiological processes. PMID:18815383

Cellulose synthase stoichiometry in aspen differs from Arabidopsis and Norway spruce.

PubMed

Zhang, Xueyang; Dominguez, Pia Guadalupe; Kumar, Manoj; Bygdell, Joakim; Miroshnichenko, Sergey; Sundberg, Bjorn; Wingsle, Gunnar; Niittyla, Totte

2018-05-14

Cellulose is synthesised at the plasma membrane by cellulose synthase complexes (CSCs) containing cellulose synthases (CESAs). Genetic analysis and CESA isoform quantification indicate that cellulose in the secondary cell walls of Arabidopsis (Arabidopsis thaliana) is synthesised by isoforms CESA4, CESA7 and CESA8 in equimolar amounts. Here, we used quantitative proteomics to investigate whether the CSC model based on Arabidopsis secondary cell wall CESA stoichiometry can be applied to the angiosperm tree aspen (Populus tremula) and the gymnosperm tree Norway spruce (Picea abies). In the developing xylem of aspen the secondary cell wall CESA stoichiometry was 3:2:1 for PtCESA8a/b : PtCESA4 : PtCESA7a/b, while in Norway spruce the stoichiometry was 1:1:1 as previously observed in Arabidopsis. Furthermore, in aspen tension wood the secondary cell wall CESA stoichiometry changed to 8:3:1 for PtCESA8a/b : PtCESA4 : PtCESA7a/b. PtCESA8b represented 73% of the total secondary cell wall CESA pool, and quantitative PCR analysis of CESA transcripts in cryo-sectioned tension wood revealed increased PtCESA8b expression during formation of the cellulose-enriched gelatinous layer while the transcripts of PtCESA4, PtCESA7a/b and PtCESA8a decreased. A wide-angle X-ray scattering analysis showed that the shift in CESA stoichiometry in tension wood coincided with an increase in crystalline cellulose microfibril diameter suggesting that the CSC CESA composition influences microfibril properties. The aspen CESA stoichiometry results raise the possibility of alternative CSC models, and suggest that homomeric PtCESA8b complexes are responsible for cellulose biosynthesis in the gelatinous layer in tension wood. {copyright, serif} 2018 American Society of Plant Biologists. All rights reserved.

Diuretics Prime Plant Immunity in Arabidopsis thaliana

PubMed Central

Noutoshi, Yoshiteru; Ikeda, Mika; Shirasu, Ken

2012-01-01

Plant activators are agrochemicals that activate the plant immune system, thereby enhancing disease resistance. Due to their prophylactic and durable effects on a wide spectrum of diseases, plant activators can provide synergistic crop protection when used in combination with traditional pest controls. Although plant activators have achieved great success in wet-rice farming practices in Asia, their use is still limited. To isolate novel plant activators applicable to other crops, we screened a chemical library using a method that can selectively identify immune-priming compounds. Here, we report the isolation and characterization of three diuretics, bumetanide, bendroflumethiazide and clopamide, as immune-priming compounds. These drugs upregulate the immunity-related cell death of Arabidopsis suspension-cultured cells induced with an avirulent strain of Pseudomonas syringae pv. tomato in a concentration-dependent manner. The application of these compounds to Arabidopsis plants confers disease resistance to not only the avirulent but also a virulent strain of the pathogen. Unlike salicylic acid, an endogenous phytohormone that governs disease resistance in response to biotrophic pathogens, the three diuretic compounds analyzed here do not induce PR1 or inhibit plant growth, showing potential as lead compounds in a practical application. PMID:23144763

Light responses in Photoperiodism in Arabidopsis thaliana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anthony R. Cashmore

2006-08-01

ADO1: An Arabidopsis blue light photoreceptor We have reported the characterization of an Arabidopsis gene encoding the ADAGIO 1 (ADO1) protein (Jarillo et al., 2001a). ADO1 contains a LOV domain, similar to WHITE COLLAR 1 (WC1), a photoreceptor for entrainment of Neurospora circadian rhythms (Froehlich et al., 2002), as well as PHOT1 and PHOT2, the blue light photoreceptors for phototropism (Briggs et al., 2001; Christie et al., 1998; Jarillo et al., 2001b; Kinoshita et al., 2001). Loss of function ado1 mutants show an unusually long periodicity for their free running circadian rhythm (Jarillo et al., 2001a). This observation holds formore » plants grown under white light as well as blue light and surprisingly, plants grown under red light also show altered circadian properties. The similarity of the LOV domain of ADO1 to those of PHOT1, PHOT2 and WC1 (known flavoprotein photoreceptors) as well as the genetic and molecular properties of ADO1, indicate that ADO1 is likely a new class of blue light photoreceptor. Indeed, the LOV domain of the related FKF1/ADO3 has been shown to bind FMN, and exhibit the in vitro photochemistry characteristic of PHOT1 (Imaizumi et al., 2003). Furthermore, ZTL/ADO1 has been shown to participate in the circadian and proteasome mediated degradation of the Arabidopsis clock protein, TOC1 (Mas et al., 2003). We also showed that the ado1 mutation selectively confers hypersensitivity to red light — when grown under red light (but not blue light) the ado1 mutant possesses an unusually short hypocotyl. This red light hypersensivity is even more severe in a triple ado1 ado2 ado3 mutant — ADO2 and ADO3 being the two other members of this ADAGIO gene family. This finding of a mutant phenotype under red light is somewhat unexpected for a protein thought to function as a photoreceptor for blue light. We have pursued our studies of ADO1 by preparing a mutant gene for which we have altered the codon for the cysteine residue conserved in all

An Arabidopsis thaliana embryo arrest mutant exhibiting germination potential

USDA-ARS?s Scientific Manuscript database

The ability to initiate radicle elongation, or germination potential, occurs in developing embryos before the completion of seed maturation. Green embryos after walking-stick stage in developing Arabidopsis thaliana seeds germinate when excised from seeds and incubated in MS media containing 1 % suc...

Zinc Oxide Nanoparticles Affect Biomass Accumulation and Photosynthesis in Arabidopsis

PubMed Central

Wang, Xiaoping; Yang, Xiyu; Chen, Siyu; Li, Qianqian; Wang, Wei; Hou, Chunjiang; Gao, Xiao; Wang, Li; Wang, Shucai

2016-01-01

Dramatic increase in the use of nanoparticles (NPs) in a variety of applications greatly increased the likelihood of the release of NPs into the environment. Zinc oxide nanoparticles (ZnO NPs) are among the most commonly used NPs, and it has been shown that ZnO NPs were harmful to several different plants. We report here the effects of ZnO NPs exposure on biomass accumulation and photosynthesis in Arabidopsis. We found that 200 and 300 mg/L ZnO NPs treatments reduced Arabidopsis growth by ∼20 and 80%, respectively, in comparison to the control. Pigments measurement showed that Chlorophyll a and b contents were reduced more than 50%, whereas carotenoid contents remain largely unaffected in 300 mg/L ZnO NPs treated Arabidopsis plants. Consistent with this, net rate of photosynthesis, leaf stomatal conductance, intercellular CO2 concentration and transpiration rate were all reduced more than 50% in 300 mg/L ZnO NPs treated plants. Quantitative RT-PCR results showed that expression levels of chlorophyll synthesis genes including CHLOROPHYLL A OXYGENASE (CAO), CHLOROPHYLL SYNTHASE (CHLG), COPPER RESPONSE DEFECT 1 (CRD1), MAGNESIUM-PROTOPORPHYRIN IX METHYLTRANSFERASE (CHLM) and MG-CHELATASE SUBUNIT D (CHLD), and photosystem structure gene PHOTOSYSTEM I SUBUNIT D-2 (PSAD2), PHOTOSYSTEM I SUBUNIT E-2 (PSAE2), PHOTOSYSTEM I SUBUNIT K (PSAK) and PHOTOSYSTEM I SUBUNIT K (PSAN) were reduced about five folds in 300 mg/L ZnO NPs treated plants. On the other hand, elevated expression, though to different degrees, of several carotenoids synthesis genes including GERANYLGERANYL PYROPHOSPHATE SYNTHASE 6 (GGPS6), PHYTOENE SYNTHASE (PSY) PHYTOENE DESATURASE (PDS), and ZETA-CAROTENE DESATURASE (ZDS) were observed in ZnO NPs treated plants. Taken together, these results suggest that toxicity effects of ZnO NPs observed in Arabidopsis was likely due to the inhibition of the expression of chlorophyll synthesis genes and photosystem structure genes, which results in the inhibition of

Elongator Plays a Positive Role in Exogenous NAD-Induced Defense Responses in Arabidopsis.

PubMed

An, Chuanfu; Ding, Yezhang; Zhang, Xudong; Wang, Chenggang; Mou, Zhonglin

2016-05-01

Extracellular NAD is emerging as an important signal molecule in animal cells, but its role in plants has not been well-established. Although it has been shown that exogenous NAD(+) activates defense responses in Arabidopsis, components in the exogenous NAD(+)-activated defense pathway remain to be fully discovered. In a genetic screen for mutants insensitive to exogenous NAD(+) (ien), we isolated a mutant named ien2. Map-based cloning revealed that IEN2 encodes ELONGATA3 (ELO3)/AtELP3, a subunit of the Arabidopsis Elongator complex, which functions in multiple biological processes, including histone modification, DNA (de)methylation, and transfer RNA modification. Mutations in the ELO3/AtELP3 gene compromise exogenous NAD(+)-induced expression of pathogenesis-related (PR) genes and resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola ES4326, and transgenic expression of the coding region of ELO3/AtELP3 in elo3/Atelp3 restores NAD(+) responsiveness to the mutant plants, demonstrating that ELO3/AtELP3 is required for exogenous NAD(+)-induced defense responses. Furthermore, mutations in genes encoding the other five Arabidopsis Elongator subunits (ELO2/AtELP1, AtELP2, ELO1/AtELP4, AtELP5, and AtELP6) also compromise exogenous NAD(+)-induced PR gene expression and resistance to P. syringae pv. maculicola ES4326. These results indicate that the Elongator complex functions as a whole in exogenous NAD(+)-activated defense signaling in Arabidopsis.

Peculiarities in formation of Arabidopsis Thaliana (L.) Heynh, generative organs under space flight conditions

NASA Technical Reports Server (NTRS)

Kordyum, Y. L.; Chernyayeva, I. I.

1983-01-01

Peculiarities in the formation of the andrecium and gynecium elements are described for Arabidopsis plants grown from the stages of two cotyledonous leaves in the Svitoblok-1 device on board the Salyut 6 orbital research station and in the laboratory. It is established that flower buds and flowers, normally formed in habitus, contain sterile elements of andrecium and gynecium whose degeneration occurs at different developmental stages of the Arabidopsis plants in the experiment under conditions of weightlessness.

Phosphate Availability Alters Architecture and Causes Changes in Hormone Sensitivity in the Arabidopsis Root System1

PubMed Central

López-Bucio, José; Hernández-Abreu, Esmeralda; Sánchez-Calderón, Lenin; Nieto-Jacobo, María Fernanda; Simpson, June; Herrera-Estrella, Luis

2002-01-01

The postembryonic developmental program of the plant root system is plastic and allows changes in root architecture to adapt to environmental conditions such as water and nutrient availability. Among essential nutrients, phosphorus (P) often limits plant productivity because of its low mobility in soil. Therefore, the architecture of the root system may determine the capacity of the plant to acquire this nutrient. We studied the effect of P availability on the development of the root system in Arabidopsis. We found that at P-limiting conditions (<50 μm), the Arabidopsis root system undergoes major architectural changes in terms of lateral root number, lateral root density, and primary root length. Treatment with auxins and auxin antagonists indicate that these changes are related to an increase in auxin sensitivity in the roots of P-deprived Arabidopsis seedlings. It was also found that the axr1-3, axr2-1, and axr4-1 Arabidopsis mutants have normal responses to low P availability conditions, whereas the iaa28-1 mutant shows resistance to the stimulatory effects of low P on root hair and lateral root formation. Analysis of ethylene signaling mutants and treatments with 1-aminocyclopropane-1-carboxylic acid showed that ethylene does not promote lateral root formation under P deprivation. These results suggest that in Arabidopsis, auxin sensitivity may play a fundamental role in the modifications of root architecture by P availability. PMID:12011355

An early nodulin-like protein accumulates in the sieve element plasma membrane of Arabidopsis.

PubMed

Khan, Junaid A; Wang, Qi; Sjölund, Richard D; Schulz, Alexander; Thompson, Gary A

2007-04-01

Membrane proteins within the sieve element-companion cell complex have essential roles in the physiological functioning of the phloem. The monoclonal antibody line RS6, selected from hybridomas raised against sieve elements isolated from California shield leaf (Streptanthus tortuosus; Brassicaceae) tissue cultures, recognizes an antigen in the Arabidopsis (Arabidopsis thaliana) ecotype Columbia that is associated specifically with the plasma membrane of sieve elements, but not companion cells, and accumulates at the earliest stages of sieve element differentiation. The identity of the RS6 antigen was revealed by reverse transcription-PCR of Arabidopsis leaf RNA using degenerate primers to be an early nodulin (ENOD)-like protein that is encoded by the expressed gene At3g20570. Arabidopsis ENOD-like proteins are encoded by a multigene family composed of several types of structurally related phytocyanins that have a similar overall domain structure of an amino-terminal signal peptide, plastocyanin-like copper-binding domain, proline/serine-rich domain, and carboxy-terminal hydrophobic domain. The amino- and carboxy-terminal domains of the 21.5-kD sieve element-specific ENOD are posttranslationally cleaved from the precursor protein, resulting in a mature peptide of approximately 15 kD that is attached to the sieve element plasma membrane via a carboxy-terminal glycosylphosphatidylinositol membrane anchor. Many of the Arabidopsis ENOD-like proteins accumulate in gametophytic tissues, whereas in both floral and vegetative tissues, the sieve element-specific ENOD is expressed only within the phloem. Members of the ENOD subfamily of the cupredoxin superfamily do not appear to bind copper and have unknown functions. Phenotypic analysis of homozygous T-DNA insertion mutants for the gene At3g20570 shows minimal alteration in vegetative growth but a significant reduction in the overall reproductive potential.

Metallothionein Induction as Indicator of Low Level Metal Exposure to Aquatic Macroinvertebrates from a Relatively Unimpacted River System in South Africa.

PubMed

Kemp, M; Wepener, V; de Kock, K N; Wolmarans, C T

2017-12-01

The Marico River is relatively unaffected by anthropogenic activities. However, metal concentrations-mainly from natural sources-occasionally exceed environmental quality guidelines. Macroinvertebrates are capable to react to these metals through processes such as the induction of metallothioneins (MTs). The aims of this study were to determine whether the induction of MTs can be used as indicator of natural metal exposure in not anthropogenically impacted systems and whether there are relationships between metal concentrations in water, sediment and macroinvertebrates and concomitant MT levels. Positive correlations were found between metals in sediment and macroinvertebrates, while there were no correlations between metal concentrations in water and macroinvertebrates. Even in a not anthropogenically impacted system, a positive correlation existed between trace metal bioaccumulation (e.g. Ni, Pb, Zn) in macroinvertebrates and the induction of MTs. There were, however, no correlations between MTs and bioaccumulation of earth metals (e.g. Al, Fe, Mn, Ti).

The Priming of Amylose Synthesis in Arabidopsis Leaves1

PubMed Central

Zeeman, Samuel C.; Smith, Steven M.; Smith, Alison M.

2002-01-01

We investigated the mechanism of amylose synthesis in Arabidopsis leaves using 14C-labeling techniques. First, we tested the hypothesis that short malto-oligosaccharides (MOS) may act as primers for granule-bound starch synthase I. We found increased amylose synthesis in isolated starch granules supplied with ADP[14C]glucose (ADP[14C]Glc) and MOS compared with granules supplied with ADP[14C]Glc but no MOS. Furthermore, using a MOS-accumulating mutant (dpe1), we found that more amylose was synthesized than in the wild type, correlating with the amount of MOS in vivo. When wild-type and mutant plants were tested in conditions where both lines had similar MOS contents, no difference in amylose synthesis was observed. We also tested the hypothesis that branches of amylopectin might serve as the primers for granule-bound starch synthase I. In this model, elongated branches of amylopectin are subsequently cleaved to form amylose. We conducted pulse-chase experiments, supplying a pulse of ADP[14C]Glc to isolated starch granules or 14CO2 to intact plants, followed by a chase period in unlabeled substrate. We detected no transfer of label from the amylopectin fraction to the amylose fraction of starch either in isolated starch granules or in intact leaves, despite varying the time course of the experiments and using a mutant line (sex4) in which high-amylose starch is synthesized. We therefore find no evidence for amylopectin-primed amylose synthesis in Arabidopsis. We propose that MOS are the primers for amylose synthesis in Arabidopsis leaves. PMID:11891261

Lysine acetylome profiling uncovers novel histone deacetylase substrate proteins in Arabidopsis.

PubMed

Hartl, Markus; Füßl, Magdalena; Boersema, Paul J; Jost, Jan-Oliver; Kramer, Katharina; Bakirbas, Ahmet; Sindlinger, Julia; Plöchinger, Magdalena; Leister, Dario; Uhrig, Glen; Moorhead, Greg Bg; Cox, Jürgen; Salvucci, Michael E; Schwarzer, Dirk; Mann, Matthias; Finkemeier, Iris

2017-10-23

Histone deacetylases have central functions in regulating stress defenses and development in plants. However, the knowledge about the deacetylase functions is largely limited to histones, although these enzymes were found in diverse subcellular compartments. In this study, we determined the proteome-wide signatures of the RPD3/HDA1 class of histone deacetylases in Arabidopsis Relative quantification of the changes in the lysine acetylation levels was determined on a proteome-wide scale after treatment of Arabidopsis leaves with deacetylase inhibitors apicidin and trichostatin A. We identified 91 new acetylated candidate proteins other than histones, which are potential substrates of the RPD3/HDA1-like histone deacetylases in Arabidopsis , of which at least 30 of these proteins function in nucleic acid binding. Furthermore, our analysis revealed that histone deacetylase 14 (HDA14) is the first organellar-localized RPD3/HDA1 class protein found to reside in the chloroplasts and that the majority of its protein targets have functions in photosynthesis. Finally, the analysis of HDA14 loss-of-function mutants revealed that the activation state of RuBisCO is controlled by lysine acetylation of RuBisCO activase under low-light conditions. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

LeCTR1, a Tomato CTR1-Like Gene, Demonstrates Ethylene Signaling Ability in Arabidopsis and Novel Expression Patterns in Tomato1

PubMed Central

Leclercq, Julie; Adams-Phillips, Lori C.; Zegzouti, Hicham; Jones, Brian; Latché, Alain; Giovannoni, James J.; Pech, Jean-Claude; Bouzayen, Mondher

2002-01-01

LeCTR1 was initially isolated by both differential display reverse transcriptase-polymerase chain reaction screening for tomato (Lycopersicon esculentum) fruit ethylene-inducible genes and through homology with the Arabidopsis CTR1 cDNA. LeCTR1 shares strong nucleotide sequence homology with Arabidopsis CTR1, a gene acting downstream of the ethylene receptor and showing similarity to the Raf family of serine/threonine protein kinases. The length of the LeCTR1 transcribed region from ATG to stop codon (12,000 bp) is more than twice that of Arabidopsis CTR1 (4,700 bp). Structural analysis reveals perfect conservation of both the number and position of introns and exons in LeCTR1 and Arabidopsis CTR1. The introns in LeCTR1 are much longer, however. To address whether this structural conservation is indicative of functional conservation of the corresponding proteins, we expressed LeCTR1 in the Arabidopsis ctr1-1 (constitutive triple response 1) mutant under the direction of the 35S promoter. Our data clearly show that ectopic expression of LeCTR1 in the Arabidopsis ctr1-1 mutant can restore normal ethylene signaling. The recovery of normal ethylene sensitivity upon heterologous expression of LeCTR1 was also confirmed by restored glucose sensitivity absent in the Arabidopsis ctr1-1 mutant. Expression studies confirm ethylene responsiveness of LeCTR1 in various tissues, including ripening fruit, and may suggest the evolution of alternate regulatory mechanisms in tomato versus Arabidopsis. PMID:12427980

Being fruitful: genetics of reproduction in Arabidopsis.

PubMed

Preuss, D

1995-04-01

Reproduction in flowering plants requires a series of interactions between the haploid and diploid phases of the life cycle of the plant. Mutations that affect these interactions have been identified in Arabidopsis, thus giving insight into the processes of gamete development and pollination. These studies promise to yield new information on diverse topics in plant biology, from cell-cell recognition to the evolution of mating interactions.

Infrared microspectroscopic imaging of plant tissues: spectral visualization of Triticum aestivum kernel and Arabidopsis leaf microstructure.

PubMed

Warren, Frederick J; Perston, Benjamin B; Galindez-Najera, Silvia P; Edwards, Cathrina H; Powell, Prudence O; Mandalari, Giusy; Campbell, Grant M; Butterworth, Peter J; Ellis, Peter R

2015-11-01

Infrared microspectroscopy is a tool with potential for studies of the microstructure, chemical composition and functionality of plants at a subcellular level. Here we present the use of high-resolution bench top-based infrared microspectroscopy to investigate the microstructure of Triticum aestivum L. (wheat) kernels and Arabidopsis leaves. Images of isolated wheat kernel tissues and whole wheat kernels following hydrothermal processing and simulated gastric and duodenal digestion were generated, as well as images of Arabidopsis leaves at different points during a diurnal cycle. Individual cells and cell walls were resolved, and large structures within cells, such as starch granules and protein bodies, were clearly identified. Contrast was provided by converting the hyperspectral image cubes into false-colour images using either principal component analysis (PCA) overlays or by correlation analysis. The unsupervised PCA approach provided a clear view of the sample microstructure, whereas the correlation analysis was used to confirm the identity of different anatomical structures using the spectra from isolated components. It was then demonstrated that gelatinized and native starch within cells could be distinguished, and that the loss of starch during wheat digestion could be observed, as well as the accumulation of starch in leaves during a diurnal period. © 2015 The Authors The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

Analysis of plastid number, size, and distribution in Arabidopsis plants by light and fluorescence microscopy.

PubMed

Pyke, Kevin

2011-01-01

Methods are described which allow one to observe chloroplasts in mesophyll cells from leaves of Arabidopsis, determine their number per cell, measure their area, and determine a value for chloroplast coverage inside mesophyll cells. Non-green plastids can also be imaged either by using staining, or by exploiting fluorescent proteins targeted to the plastid in non-green parts of the plant, such as the roots, in transgenic Arabidopsis.

Kinetic model of cadmium accumulation and elimination and metallothionein response in Ruditapes decussatus.

PubMed

Serafim, Angela; Bebianno, Maria João

2007-05-01

The aim of the present study was to determine the response of metallothionein (MT) during Cd accumulation and elimination in different tissues of the estuarine bivalve Ruditapes decussatus exposed to two nominal Cd concentrations (4 and 40 microg/L) for 40 d, followed by a depuration period of 50 d. Cadmium was accumulated in all tissues of R. decussatus at both exposure concentrations, and the accumulation was tissue dependent. Use of the kinetic model showed that in the gills and remaining tissues, Cd was assimilated faster at the beginning of the exposure and decreased with time, possibly limited by the diffusion rate of this metal within the cell. In the digestive gland, however, the Cd was continuously accumulated. This could reflect that the Cd uptake rate is considerably higher than the loss rate and, therefore, that this tissue has a higher capacity to accumulate Cd compared to the other two tissues. Moreover, the application of this kinetic model in the different subcellular fractions showed that the bioconcentration factor was significantly higher in the low-molecular-weight fraction (where MT is found), suggesting that this fraction binds Cd faster, with a high uptake rate (K(u) = 32/d), and eliminates this metal more slowly (K(1) = 0.005/d). During the depuration phase, MT decreased simultaneously with Cd elimination in all tissues, although with a shorter half-life. In conclusion, the MT response prevented Cd in the tissues of R. decussatus from interfering in the normal clam metabolism; therefore, MT acts as a detoxification mechanism of Cd.

Expression profiling during arabidopsis/downy mildew interaction reveals a highly-expressed effector that attenuates responses to salicylic acid.

PubMed

Asai, Shuta; Rallapalli, Ghanasyam; Piquerez, Sophie J M; Caillaud, Marie-Cécile; Furzer, Oliver J; Ishaque, Naveed; Wirthmueller, Lennart; Fabro, Georgina; Shirasu, Ken; Jones, Jonathan D G

2014-10-01

Plants have evolved strong innate immunity mechanisms, but successful pathogens evade or suppress plant immunity via effectors delivered into the plant cell. Hyaloperonospora arabidopsidis (Hpa) causes downy mildew on Arabidopsis thaliana, and a genome sequence is available for isolate Emoy2. Here, we exploit the availability of genome sequences for Hpa and Arabidopsis to measure gene-expression changes in both Hpa and Arabidopsis simultaneously during infection. Using a high-throughput cDNA tag sequencing method, we reveal expression patterns of Hpa predicted effectors and Arabidopsis genes in compatible and incompatible interactions, and promoter elements associated with Hpa genes expressed during infection. By resequencing Hpa isolate Waco9, we found it evades Arabidopsis resistance gene RPP1 through deletion of the cognate recognized effector ATR1. Arabidopsis salicylic acid (SA)-responsive genes including PR1 were activated not only at early time points in the incompatible interaction but also at late time points in the compatible interaction. By histochemical analysis, we found that Hpa suppresses SA-inducible PR1 expression, specifically in the haustoriated cells into which host-translocated effectors are delivered, but not in non-haustoriated adjacent cells. Finally, we found a highly-expressed Hpa effector candidate that suppresses responsiveness to SA. As this approach can be easily applied to host-pathogen interactions for which both host and pathogen genome sequences are available, this work opens the door towards transcriptome studies in infection biology that should help unravel pathogen infection strategies and the mechanisms by which host defense responses are overcome.

Model-based analysis of Arabidopsis leaf epidermal cells reveals distinct division and expansion patterns for pavement and guard cells.

PubMed

Asl, Leila Kheibarshekan; Dhondt, Stijn; Boudolf, Véronique; Beemster, Gerrit T S; Beeckman, Tom; Inzé, Dirk; Govaerts, Willy; De Veylder, Lieven

2011-08-01

To efficiently capture sunlight for photosynthesis, leaves typically develop into a flat and thin structure. This development is driven by cell division and expansion, but the individual contribution of these processes is currently unknown, mainly because of the experimental difficulties to disentangle them in a developing organ, due to their tight interconnection. To circumvent this problem, we built a mathematic model that describes the possible division patterns and expansion rates for individual epidermal cells. This model was used to fit experimental data on cell numbers and sizes obtained over time intervals of 1 d throughout the development of the first leaf pair of Arabidopsis (Arabidopsis thaliana). The parameters were obtained by a derivative-free optimization method that minimizes the differences between the predicted and experimentally observed cell size distributions. The model allowed us to calculate probabilities for a cell to divide into guard or pavement cells, the maximum size at which it can divide, and its average cell division and expansion rates at each point during the leaf developmental process. Surprisingly, average cell cycle duration remained constant throughout leaf development, whereas no evidence for a maximum cell size threshold for cell division of pavement cells was found. Furthermore, the model predicted that neighboring cells of different sizes within the epidermis expand at distinctly different relative rates, which could be verified by direct observations. We conclude that cell division seems to occur independently from the status of cell expansion, whereas the cell cycle might act as a timer rather than as a size-regulated machinery.

MicroRNA857 Is Involved in the Regulation of Secondary Growth of Vascular Tissues in Arabidopsis1

PubMed Central

Zhao, Yuanyuan; Lin, Sen; Qiu, Zongbo; Cao, Dechang; Wen, Jialong; Deng, Xin; Wang, Xiaohua; Lin, Jinxing; Li, Xiaojuan

2015-01-01

MicroRNAs (miRNAs) are endogenous small RNAs that repress target gene expression posttranscriptionally, and are critically involved in various developmental processes and responses to environmental stresses in eukaryotes. MiRNA857 is not widely distributed in plants and is encoded by a single gene, AtMIR857, in Arabidopsis (Arabidopsis thaliana). The functions of miR857 and its mechanisms in regulating plant growth and development are still unclear. Here, by means of genetic analysis coupled with cytological studies, we investigated the expression pattern and regulation mechanism of miR857 and its biological functions in Arabidopsis development. We found that miR857 regulates its target gene, Arabidopsis LACCASE7, at the transcriptional level, thereby reducing laccase activity. Using stimulated Raman scattering and x-ray microtomography three-dimensional analyses, we showed that miR857 was involved in the regulation of lignin content and consequently morphogenesis of the secondary xylem. In addition, miR857 was activated by SQUAMOSA PROMOTER BINDING PROTEIN-LIKE7 in response to low copper conditions. Collectively, these findings demonstrate the role of miR857 in the regulation of secondary growth of vascular tissues in Arabidopsis and reveal a unique control mechanism for secondary growth based on the miR857 expression in response to copper deficiency. PMID:26511915

A prominent role for the CBF cold response pathway in configuring the low-temperature metabolome of Arabidopsis

PubMed Central

Cook, Daniel; Fowler, Sarah; Fiehn, Oliver; Thomashow, Michael F.

2004-01-01

The Arabidopsis CBF cold response pathway has a central role in cold acclimation, the process whereby plants increase in freezing tolerance in response to low nonfreezing temperatures. Here we examined the changes that occur in the Arabidopsis metabolome in response to low temperature and assessed the role of the CBF cold response pathway in bringing about these modifications. Of 434 metabolites monitored by GC-time-of-flight MS, 325 (75%) were found to increase in Arabidopsis Wassilewskija-2 (Ws-2) plants in response to low temperature. Of these 325 metabolites, 256 (79%) also increased in nonacclimated Ws-2 plants in response to overexpression of C-repeat/dehydration responsive element-binding factor (CBF)3. Extensive cold-induced changes also occurred in the metabolome of Arabidopsis Cape Verde Islands-1 (Cvi-1) plants, which were found to be less freezing tolerant than Ws-2 plants. However, low-temperature-induced expression of CBF1, CBF2, CBF3, and CBF-targeted genes was much lower in Cvi-1 than in Ws-2 plants, and the low-temperature metabolome of Cvi-1 plants was depleted in metabolites affected by CBF3 overexpression. Taken together, the results indicate that the metabolome of Arabidopsis is extensively reconfigured in response to low temperature, and that the CBF cold response pathway has a prominent role in this process. PMID:15383661

Salinity Is an Agent of Divergent Selection Driving Local Adaptation of Arabidopsis to Coastal Habitats1[OPEN

PubMed Central

Teres, Joana; Bomblies, Kirsten; Douglas, Alex; Salt, David E.

2015-01-01

Understanding the molecular mechanism of adaptive evolution in plants provides insights into the selective forces driving adaptation and the genetic basis of adaptive traits with agricultural value. The genomic resources available for Arabidopsis (Arabidopsis thaliana) make it well suited to the rapid molecular dissection of adaptive processes. Although numerous potentially adaptive loci have been identified in Arabidopsis, the consequences of divergent selection and migration (both important aspects of the process of local adaptation) for Arabidopsis are not well understood. Here, we use a multiyear field-based reciprocal transplant experiment to detect local populations of Arabidopsis composed of multiple small stands of plants (demes) that are locally adapted to the coast and adjacent inland habitats in northeastern Spain. We identify fitness tradeoffs between plants from these different habitats when grown together in inland and coastal common gardens and also, under controlled conditions in soil excavated from coastal and inland sites. Plants from the coastal habitat also outperform those from inland when grown under high salinity, indicating local adaptation to soil salinity. Sodium can be toxic to plants, and we find its concentration to be elevated in soil and plants sampled at the coast. We conclude that the local adaptation that we observe between adjacent coastal and inland populations is caused by ongoing divergent selection driven by the differential salinity between coastal and inland soils. PMID:26034264

A Genome-Wide Functional Investigation into the Roles of Receptor-Like Proteins in Arabidopsis1[W][OA

PubMed Central

Wang, Guodong; Ellendorff, Ursula; Kemp, Ben; Mansfield, John W.; Forsyth, Alec; Mitchell, Kathy; Bastas, Kubilay; Liu, Chun-Ming; Woods-Tör, Alison; Zipfel, Cyril; de Wit, Pierre J.G.M.; Jones, Jonathan D.G.; Tör, Mahmut; Thomma, Bart P.H.J.

2008-01-01

Receptor-like proteins (RLPs) are cell surface receptors that typically consist of an extracellular leucine-rich repeat domain, a transmembrane domain, and a short cytoplasmatic tail. In several plant species, RLPs have been found to play a role in disease resistance, such as the tomato (Solanum lycopersicum) Cf and Ve proteins and the apple (Malus domestica) HcrVf2 protein that mediate resistance against the fungal pathogens Cladosporium fulvum, Verticillium spp., and Venturia inaequalis, respectively. In addition, RLPs play a role in plant development; Arabidopsis (Arabidopsis thaliana) TOO MANY MOUTHS (TMM) regulates stomatal distribution, while Arabidopsis CLAVATA2 (CLV2) and its functional maize (Zea mays) ortholog FASCINATED EAR2 regulate meristem maintenance. In total, 57 RLP genes have been identified in the Arabidopsis genome and a genome-wide collection of T-DNA insertion lines was assembled. This collection was functionally analyzed with respect to plant growth and development and sensitivity to various stress responses, including susceptibility toward pathogens. A number of novel developmental phenotypes were revealed for our CLV2 and TMM insertion mutants. In addition, one AtRLP gene was found to mediate abscisic acid sensitivity and another AtRLP gene was found to influence nonhost resistance toward Pseudomonas syringae pv phaseolicola. This genome-wide collection of Arabidopsis RLP gene T-DNA insertion mutants provides a tool for future investigations into the biological roles of RLPs. PMID:18434605

Target of Rapamycin Is a Key Player for Auxin Signaling Transduction in Arabidopsis

PubMed Central

Deng, Kexuan; Yu, Lihua; Zheng, Xianzhe; Zhang, Kang; Wang, Wanjing; Dong, Pan; Zhang, Jiankui; Ren, Maozhi

2016-01-01

Target of rapamycin (TOR), a master sensor for growth factors and nutrition availability in eukaryotic species, is a specific target protein of rapamycin. Rapamycin inhibits TOR kinase activity viaFK506 binding protein 12 kDa (FKBP12) in all examined heterotrophic eukaryotic organisms. In Arabidopsis, several independent studies have shown that AtFKBP12 is non-functional under aerobic condition, but one study suggests that AtFKBP12 is functional during anaerobic growth. However, the functions of AtFKBP12 have never been examined in parallel under aerobic and anaerobic growth conditions so far. To this end, we cloned the FKBP12 gene of humans, yeast, and Arabidopsis, respectively. Transgenic plants were generated, and pharmacological examinations were performed in parallel with Arabidopsis under aerobic and anaerobic conditions. ScFKBP12 conferred plants with the strongest sensitivity to rapamycin, followed by HsFKBP12, whereas AtFKBP12 failed to generate rapamycin sensitivity under aerobic condition. Upon submergence, yeast and human FKBP12 can significantly block cotyledon greening while Arabidopsis FKBP12 only retards plant growth in the presence of rapamycin, suggesting that hypoxia stress could partially restore the functions of AtFKBP12 to bridge the interaction between rapamycin and TOR. To further determine if communication between TOR and auxin signaling exists in plants, yeast FKBP12 was introduced into DR5::GUS homozygous plants. The transgenic plants DR5/BP12 were then treated with rapamycin or KU63794 (a new inhibitor of TOR). GUS staining showed that the auxin content of root tips decreased compared to the control. DR5/BP12 plants lost sensitivity to auxin after treatment with rapamycin. Auxin-defective phenotypes, including short primary roots, fewer lateral roots, and loss of gravitropism, occurred in DR5/BP12 plants when seedlings were treated with rapamycin+KU63794. This indicated that the combination of rapamycin and KU63794 can significantly

Molecular signatures in Arabidopsis thaliana in response to insect attack and bacterial infection.

PubMed

Barah, Pankaj; Winge, Per; Kusnierczyk, Anna; Tran, Diem Hong; Bones, Atle M

2013-01-01

Under the threat of global climatic change and food shortages, it is essential to take the initiative to obtain a comprehensive understanding of common and specific defence mechanisms existing in plant systems for protection against different types of biotic invaders. We have implemented an integrated approach to analyse the overall transcriptomic reprogramming and systems-level defence responses in the model plant species Arabidopsis thaliana (A. thaliana henceforth) during insect Brevicoryne brassicae (B. brassicae henceforth) and bacterial Pseudomonas syringae pv. tomato strain DC3000 (P. syringae henceforth) attacks. The main aim of this study was to identify the attacker-specific and general defence response signatures in A. thaliana when attacked by phloem-feeding aphids or pathogenic bacteria. The obtained annotated networks of differentially expressed transcripts indicated that members of transcription factor families, such as WRKY, MYB, ERF, BHLH and bZIP, could be crucial for stress-specific defence regulation in Arabidopsis during aphid and P. syringae attack. The defence response pathways, signalling pathways and metabolic processes associated with aphid attack and P. syringae infection partially overlapped. Components of several important biosynthesis and signalling pathways, such as salicylic acid (SA), jasmonic acid (JA), ethylene (ET) and glucosinolates, were differentially affected during the two the treatments. Several stress-regulated transcription factors were known to be associated with stress-inducible microRNAs. The differentially regulated gene sets included many signature transcription factors, and our co-expression analysis showed that they were also strongly co-expressed during 69 other biotic stress experiments. Defence responses and functional networks that were unique and specific to aphid or P. syringae stresses were identified. Furthermore, our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and

Target of Rapamycin Signaling Regulates Metabolism, Growth, and Life Span in Arabidopsis[W][OA

PubMed Central

Ren, Maozhi; Venglat, Prakash; Qiu, Shuqing; Feng, Li; Cao, Yongguo; Wang, Edwin; Xiang, Daoquan; Wang, Jinghe; Alexander, Danny; Chalivendra, Subbaiah; Logan, David; Mattoo, Autar; Selvaraj, Gopalan; Datla, Raju

2012-01-01

Target of Rapamycin (TOR) is a major nutrition and energy sensor that regulates growth and life span in yeast and animals. In plants, growth and life span are intertwined not only with nutrient acquisition from the soil and nutrition generation via photosynthesis but also with their unique modes of development and differentiation. How TOR functions in these processes has not yet been determined. To gain further insights, rapamycin-sensitive transgenic Arabidopsis thaliana lines (BP12) expressing yeast FK506 Binding Protein12 were developed. Inhibition of TOR in BP12 plants by rapamycin resulted in slower overall root, leaf, and shoot growth and development leading to poor nutrient uptake and light energy utilization. Experimental limitation of nutrient availability and light energy supply in wild-type Arabidopsis produced phenotypes observed with TOR knockdown plants, indicating a link between TOR signaling and nutrition/light energy status. Genetic and physiological studies together with RNA sequencing and metabolite analysis of TOR-suppressed lines revealed that TOR regulates development and life span in Arabidopsis by restructuring cell growth, carbon and nitrogen metabolism, gene expression, and rRNA and protein synthesis. Gain- and loss-of-function Ribosomal Protein S6 (RPS6) mutants additionally show that TOR function involves RPS6-mediated nutrition and light-dependent growth and life span in Arabidopsis. PMID:23275579

Wheat Transcription Factor TaAREB3 Participates in Drought and Freezing Tolerances in Arabidopsis.

PubMed

Wang, Jingyi; Li, Qian; Mao, Xinguo; Li, Ang; Jing, Ruilian

2016-01-01

AREB (ABA response element binding) proteins in plants play direct regulatory roles in response to multiple stresses, but their functions in wheat (Triticum aestivum L.) are not clear. In the present study, TaAREB3, a new member of the AREB transcription factor family, was isolated from wheat. Sequence analysis showed that the TaAREB3 protein is composed of three parts, a conserved N-terminal, a variable M region, and a conserved C-terminal with a bZIP domain. It belongs to the group A subfamily of bZIP transcription factors. TaAREB3 was constitutively expressed in stems, leaves, florets, anthers, pistils, seeds, and most highly, in roots. TaAREB3 gene expression was induced with abscisic acid (ABA) and low temperature stress, and its protein was localized in the nucleus when transiently expressed in tobacco epidermal cells and stably expressed in transgenic Arabidopsis. TaAREB3 protein has transcriptional activation activity, and can bind to the ABRE cis-element in vitro. Overexpression of TaAREB3 in Arabidopsis not only enhanced ABA sensitivity, but also strengthened drought and freezing tolerances. TaAREB3 also activated RD29A, RD29B, COR15A, and COR47 by binding to their promoter regions in transgenic Arabidopsis. These results demonstrated that TaAREB3 plays an important role in drought and freezing tolerances in Arabidopsis.

Wheat Transcription Factor TaAREB3 Participates in Drought and Freezing Tolerances in Arabidopsis

PubMed Central

Wang, Jingyi; Li, Qian; Mao, Xinguo; Li, Ang; Jing, Ruilian

2016-01-01

AREB (ABA response element binding) proteins in plants play direct regulatory roles in response to multiple stresses, but their functions in wheat (Triticum aestivum L.) are not clear. In the present study, TaAREB3, a new member of the AREB transcription factor family, was isolated from wheat. Sequence analysis showed that the TaAREB3 protein is composed of three parts, a conserved N-terminal, a variable M region, and a conserved C-terminal with a bZIP domain. It belongs to the group A subfamily of bZIP transcription factors. TaAREB3 was constitutively expressed in stems, leaves, florets, anthers, pistils, seeds, and most highly, in roots. TaAREB3 gene expression was induced with abscisic acid (ABA) and low temperature stress, and its protein was localized in the nucleus when transiently expressed in tobacco epidermal cells and stably expressed in transgenic Arabidopsis. TaAREB3 protein has transcriptional activation activity, and can bind to the ABRE cis-element in vitro. Overexpression of TaAREB3 in Arabidopsis not only enhanced ABA sensitivity, but also strengthened drought and freezing tolerances. TaAREB3 also activated RD29A, RD29B, COR15A, and COR47 by binding to their promoter regions in transgenic Arabidopsis. These results demonstrated that TaAREB3 plays an important role in drought and freezing tolerances in Arabidopsis. PMID:26884722

Proteomic Responses in Arabidopsis thaliana Seedlings Treated with Ethylene

USDA-ARS?s Scientific Manuscript database

Ethylene (ET) is a volatile plant growth hormone that most famously modulates fruit ripening, but it also controls plant growth, development and stress responses. In Arabidopsis thaliana, ET is perceived by receptors in the endoplasmic reticulum, and a signal is transduced through a protein kinase,...

Arabidopsis transcriptional responses differentiate between O3 and herbicides

EPA Science Inventory

Using published data based on Affymetrix ATH1 Gene-Chips we characterized the transcriptional response of Arabidopsis thaliana Columbia to O3 and a few other major environmental stresses including oxidative stress . A set of 101 markers could be extracted which provided a compo...

The Arabidopsis Family GT43 Glycosyltransferases Form Two Functionally Nonredundant Groups Essential for the Elongation of Glucuronoxylan Backbone

EPA Science Inventory

There exist four members of family GT43 glycosyltransferases in the Arabidopsis (Arabidopsis thaliana) genome, and mutations of two of them, IRX9 and IRX14, have previously been shown to cause a defect in glucuronoxylan (GX) biosynthesis. However, it is currently unknown whether ...

The Arabidopsis COBRA Protein Facilitates Cellulose Crystallization at the Plasma Membrane*

PubMed Central

Sorek, Nadav; Sorek, Hagit; Kijac, Aleksandra; Szemenyei, Heidi J.; Bauer, Stefan; Hématy, Kian; Wemmer, David E.; Somerville, Chris R.

2014-01-01

Mutations in the Arabidopsis COBRA gene lead to defects in cellulose synthesis but the function of COBRA is unknown. Here we present evidence that COBRA localizes to discrete particles in the plasma membrane and is sensitive to inhibitors of cellulose synthesis, suggesting that COBRA and the cellulose synthase complex reside in close proximity on the plasma membrane. Live-cell imaging of cellulose synthesis indicated that, once initiated, cellulose synthesis appeared to proceed normally in the cobra mutant. Using isothermal calorimetry, COBRA was found to bind individual β1–4-linked glucan chains with a KD of 3.2 μm. Competition assays suggests that COBRA binds individual β1–4-linked glucan chains with higher affinity than crystalline cellulose. Solid-state nuclear magnetic resonance studies of the cell wall of the cobra mutant also indicated that, in addition to decreases in cellulose amount, the properties of the cellulose fibrils and other cell wall polymers differed from wild type by being less crystalline and having an increased number of reducing ends. We interpret the available evidence as suggesting that COBRA facilitates cellulose crystallization from the emerging β1–4-glucan chains by acting as a “polysaccharide chaperone.” PMID:25331944

Vitamin E confers cytoprotective effects on cardiomyocytes under conditions of heat stress by increasing the expression of metallothionein.

PubMed

Wang, Xiaowu; Dong, Wenpeng; Yuan, Binbin; Yang, Yongchao; Yang, Dongpeng; Lin, Xi; Chen, Changfu; Zhang, Weida

2016-05-01

Heat stress (HS) is commonly used to refer to the heat load that an individual is subjected to due to either metabolic heat, or environmental factors, including high temperatures and high humidity levels. HS has been reported to affect and even damage the functioning of various organs; overexposure to high temperatures and high humidity may lead to accidental deaths. It has been suggested that the cardiovascular system is primarily targeted by exposure to HS conditions; the HS-induced dysfunction of cardiomyocytes, which is characterized by mitochondrial dysfunction, may result in the development of cardiovascular diseases. The excessive production of reactive oxygen species (ROS) also participates in mitochondrial dysfunction. However, effective methods for the prevention and treatment of mitochondrial and cardiovascular dysfunction induced by exposure to HS are lacking. In the present study, we hypothesized that vitamin E (VE), an antioxidant, is capable of preventing oxidative stress and mitochondrial injury in cardiomyocytes induced by exposure to HS. The results revealed that pre‑treatment with VE increased the expression of metallothionein (MT), which has previously been reported to confer cytoprotective effects, particularly on the cardiovascular system. Pre-treatment with VE restored mitochondrial function in cardiomyocytes under conditions of HS by increasing the expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM), and by increasing adenosine triphosphate (ATP) levels. Furthermore, pre-treatment with VE decreased the production of ROS, which was induced by exposure to HS and thus exerted antioxidant effects. In addition, pre-treatment with VE attenuated oxidative stress induced by exposure to HS, as demonstrated by the increased levels of antioxidant enzymes [superoxide dismutase (SOD) and glutathione (GSH)], and by the decreased levels

Plastid Ontogeny during Petal Development in Arabidopsis1

PubMed Central

Pyke, Kevin A.; Page, Anton M.

1998-01-01

Imaging of chlorophyll autofluorescence by confocal microscopy in intact whole petals of Arabidopsis thaliana has been used to analyze chloroplast development and redifferentiation during petal development. Young petals dissected from unopened buds contained green chloroplasts throughout their structure, but as the upper part of the petal lamina developed and expanded, plastids lost their chlorophyll and redifferentiated into leukoplasts, resulting in a white petal blade. Normal green chloroplasts remained in the stalk of the mature petal. In epidermal cells the chloroplasts were normal and green, in stark contrast with leaf epidermal cell plastids. In addition, the majority of these chloroplasts had dumbbell shapes, typical of dividing chloroplasts, and we suggest that the rapid expansion of petal epidermal cells may be a trigger for the initiation of chloroplast division. In petals of the Arabidopsis plastid division mutant arc6, the conversion of chloroplasts into leukoplasts was unaffected in spite of the greatly enlarged size and reduced number of arc6 chloroplasts in cells in the petal base, resulting in few enlarged leukoplasts in cells from the white lamina of arc6 petals. PMID:9489024

Metallothionein Gene Family in the Sea Urchin Paracentrotus lividus: Gene Structure, Differential Expression and Phylogenetic Analysis

PubMed Central

Ragusa, Maria Antonietta; Nicosia, Aldo; Costa, Salvatore; Cuttitta, Angela; Gianguzza, Fabrizio

2017-01-01

Metallothioneins (MT) are small and cysteine-rich proteins that bind metal ions such as zinc, copper, cadmium, and nickel. In order to shed some light on MT gene structure and evolution, we cloned seven Paracentrotus lividus MT genes, comparing them to Echinodermata and Chordata genes. Moreover, we performed a phylogenetic analysis of 32 MTs from different classes of echinoderms and 13 MTs from the most ancient chordates, highlighting the relationships between them. Since MTs have multiple roles in the cells, we performed RT-qPCR and in situ hybridization experiments to understand better MT functions in sea urchin embryos. Results showed that the expression of MTs is regulated throughout development in a cell type-specific manner and in response to various metals. The MT7 transcript is expressed in all tissues, especially in the stomach and in the intestine of the larva, but it is less metal-responsive. In contrast, MT8 is ectodermic and rises only at relatively high metal doses. MT5 and MT6 expression is highly stimulated by metals in the mesenchyme cells. Our results suggest that the P. lividus MT family originated after the speciation events by gene duplications, evolving developmental and environmental sub-functionalization. PMID:28417916

Molecular actions of two synthetic brassinosteroids, iso-carbaBL and 6-deoxoBL, which cause altered physiological activities between Arabidopsis and rice.

PubMed

Nakamura, Ayako; Tochio, Naoya; Fujioka, Shozo; Ito, Shinsaku; Kigawa, Takanori; Shimada, Yukihisa; Matsuoka, Makoto; Yoshida, Shigeo; Kinoshita, Toshinori; Asami, Tadao; Seto, Hideharu; Nakano, Takeshi

2017-01-01

Brassinosteroid (BR) is an important plant hormone that is perceived by the BRASSINOSTEROID INSENSITIVE 1 (BRI1) receptor. BRI1 is conserved among dicot and monocot species; however, the molecular mechanism underlying BR perception in monocots is not fully understood. We synthesised two BRs, iso-carbabrassinolide (iso-carbaBL) and 6-deoxoBL, which have different BR activities in Arabidopsis thaliana (Arabidopsis) and rice. Our bioassay indicated that iso-carbaBL has relatively strong BR activity in Arabidopsis, but is inactive in rice and competitively inhibits BR activity. The bioactivity of 6-deoxoBL was similar to that of BL in Arabidopsis, but was much lower in rice. Binding experiments using recombinant Arabidopsis and rice BRI1 protein fragments suggested that iso-carbaBL and 6-deoxoBL bind to both receptors. These results showed that iso-carbaBL and 6-deoxoBL act as an antagonist and agonist, respectively, of BRs in rice. A docking simulation analysis suggested that iso-carbaBL fits deeper in the binding pocket to block the binding of active BR to rice BRI1. The simulated binding energy of 6-deoxoBL with rice BRI1 is much lower than that with Arabidopsis BRI1. The possible structural characteristics of rice BRI1 were determined based on the difference in the BR activities of iso-carbaBL and 6-deoxoBL in Arabidopsis and rice.

Strigolactones Suppress Adventitious Rooting in Arabidopsis and Pea1[C][W][OA

PubMed Central

Rasmussen, Amanda; Mason, Michael Glenn; De Cuyper, Carolien; Brewer, Philip B.; Herold, Silvia; Agusti, Javier; Geelen, Danny; Greb, Thomas; Goormachtig, Sofie; Beeckman, Tom; Beveridge, Christine Anne

2012-01-01

Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation. PMID:22323776

Transposon mutagenesis reveals differential pathogenesis of Ralstonia solanacearum on tomato and Arabidopsis.

PubMed

Lin, Yu-Mei; Chou, I-Chun; Wang, Jaw-Fen; Ho, Fang-I; Chu, Yu-Ju; Huang, Pei-Cheng; Lu, Der-Kang; Shen, Hwei-Ling; Elbaz, Mounira; Huang, Shu-Mei; Cheng, Chiu-Ping

2008-09-01

Ralstonia solanacearum causes a deadly wilting disease on a wide range of crops. To elucidate pathogenesis of this bacterium in different host plants, we set out to identify R. solanacearum genes involved in pathogenesis by screening random transposon insertion mutants of a highly virulent strain, Pss190, on tomato and Arabidopsis thaliana. Mutants exhibiting various decreased virulence levels on these two hosts were identified. Sequence analysis showed that most, but not all, of the identified pathogenesis genes are conserved among distinct R. solanacearum strains. A few of the disrupted loci were not reported previously as being involved in R. solanacearum pathogenesis. Notably, a group of mutants exhibited differential pathogenesis on tomato and Arabidopsis. These results were confirmed by characterizing allelic mutants in one other R. solanacearum strain of the same phylotype. The significantly decreased mutants' colonization in Arabidopsis was found to be correlated with differential pathogenesis on these two plants. Differential requirement of virulence genes suggests adaptation of this bacterium in different host environments. Together, this study reveals commonalities and differences of R. solanacearum pathogenesis on single solanaceous and nonsolanaceous hosts, and provides important new insights into interactions between R. solanacearum and different host plants.

ML3: a novel regulator of herbivory-induced responses in Arabidopsis thaliana

PubMed Central

Bejai, Sarosh

2013-01-01

ML (MD2-related lipid recognition) proteins are known to enhance innate immune responses in mammals. This study reports the analysis of the putative ML gene family in Arabidopsis thaliana and suggests a role for the ML3 gene in herbivory-associated responses in plants. Feeding by larvae of the Lepidopteran generalist herbivore Spodoptera littoralis and larvae of the specialist herbivore Plutella xylostella activated ML3 transcription in leaf tissues. ML3 loss-of-function Arabidopsis plants were compromised in the upregulation of herbivory-induced genes and displayed a semi-dwarf phenotype. Herbivory bioassays showed that larvae of S. littoralis fed on ml3 mutant plants gained more weight compared to larvae fed on wild-type plants while larvae of P. xylostella did not show any significant difference. Virus-induced gene silencing of ML3 expression in plants compromised in jasmonic acid (JA) and salicylic acid (SA) signalling revealed a complex role of ML3 in JA/defence signalling affecting both JA- and SA-dependent responses. The data suggest that ML3 is involved in herbivory-mediated responses in Arabidopsis and that it has a potential role in herbivory-associated molecular pattern recognition. PMID:23314818

Arabidopsis mitochondrial protein slow embryo development1 is essential for embryo development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ju, Yan; Liu, Chunying; Lu, Wenwen

The plant seeds formation are crucial parts in reproductive process in seed plants as well as food source for humans. Proper embryo development ensure viable seed formation. Here, we showed an Arabidopsis T-DNA insertion mutant slow embryo development1 (sed1) which exhibited retarded embryogenesis, led to aborted seeds. Embryo without SED1 developed slower compared to normal one and could be recognized at early globular stage by its white appearance. In later development stage, storage accumulated poorly with less protein and lipid body production. In vitro culture did not rescue albino embryo. SED1 encoded a protein targeted to mitochondria. Transmission electron microscopic analysismore » revealed that mitochondria developed abnormally, and more strikingly plastid failed to construct grana in time in sed1/sed1 embryo. These data indicated that SED1 is indispensable for embryogenesis in Arabidopsis, and the mitochondria may be involved in the regulation of many aspects of seed development. -- Highlights: •Arabidopsis SED1 is essential for embryo development. •The sed1 embryo accumulates less storage and has abnormal ultrastructure. •SED1 localizes to the mitochondrion.« less

Arabidopsis phenotyping through Geometric Morphometrics.

PubMed

Manacorda, Carlos A; Asurmendi, Sebastian

2018-06-18

Recently, much technical progress was achieved in the field of plant phenotyping. High-throughput platforms and the development of improved algorithms for rosette image segmentation make it now possible to extract shape and size parameters for genetic, physiological and environmental studies on a large scale. The development of low-cost phenotyping platforms and freeware resources make it possible to widely expand phenotypic analysis tools for Arabidopsis. However, objective descriptors of shape parameters that could be used independently of platform and segmentation software used are still lacking and shape descriptions still rely on ad hoc or even sometimes contradictory descriptors, which could make comparisons difficult and perhaps inaccurate. Modern geometric morphometrics is a family of methods in quantitative biology proposed to be the main source of data and analytical tools in the emerging field of phenomics studies. Based on the location of landmarks (corresponding points) over imaged specimens and by combining geometry, multivariate analysis and powerful statistical techniques, these tools offer the possibility to reproducibly and accurately account for shape variations amongst groups and measure them in shape distance units. Here, a particular scheme of landmarks placement on Arabidopsis rosette images is proposed to study shape variation in the case of viral infection processes. Shape differences between controls and infected plants are quantified throughout the infectious process and visualized. Quantitative comparisons between two unrelated ssRNA+ viruses are shown and reproducibility issues are assessed. Combined with the newest automated platforms and plant segmentation procedures, geometric morphometric tools could boost phenotypic features extraction and processing in an objective, reproducible manner.

The Arabidopsis Information Resource: Making and Mining the ‘Gold Standard’ Annotated Reference Plant Genome

PubMed Central

Berardini, Tanya Z.; Reiser, Leonore; Li, Donghui; Mezheritsky, Yarik; Muller, Robert; Strait, Emily; Huala, Eva

2015-01-01

The Arabidopsis Information Resource (TAIR) is a continuously updated, online database of genetic and molecular biology data for the model plant Arabidopsis thaliana that provides a global research community with centralized access to data for over 30,000 Arabidopsis genes. TAIR’s biocurators systematically extract, organize, and interconnect experimental data from the literature along with computational predictions, community submissions, and high throughput datasets to present a high quality and comprehensive picture of Arabidopsis gene function. TAIR provides tools for data visualization and analysis, and enables ordering of seed and DNA stocks, protein chips and other experimental resources. TAIR actively engages with its users who contribute expertise and data that augments the work of the curatorial staff. TAIR’s focus in an extensive and evolving ecosystem of online resources for plant biology is on the critically important role of extracting experimentally-based research findings from the literature and making that information computationally accessible. In response to the loss of government grant funding, the TAIR team founded a nonprofit entity, Phoenix Bioinformatics, with the aim of developing sustainable funding models for biological databases, using TAIR as a test case. Phoenix has successfully transitioned TAIR to subscription-based funding while still keeping its data relatively open and accessible. PMID:26201819

Cell fate in the Arabidopsis root epidermis is determined by competition between WEREWOLF and CAPRICE.

PubMed

Song, Sang-Kee; Ryu, Kook Hui; Kang, Yeon Hee; Song, Jae Hyo; Cho, Young-Hee; Yoo, Sang-Dong; Schiefelbein, John; Lee, Myeong Min

2011-11-01

The root hair and nonhair cells in the Arabidopsis (Arabidopsis thaliana) root epidermis are specified by a suite of transcriptional regulators. Two of these are WEREWOLF (WER) and CAPRICE (CPC), which encode MYB transcription factors that are required for promoting the nonhair cell fate and the hair cell fate, respectively. However, the precise function and relationship between these transcriptional regulators have not been fully defined experimentally. Here, we examine these issues by misexpressing the WER gene using the GAL4-upstream activation sequence transactivation system. We find that WER overexpression in the Arabidopsis root tip is sufficient to cause epidermal cells to adopt the nonhair cell fate through direct induction of GLABRA2 (GL2) gene expression. We also show that GLABRA3 (GL3) and ENHANCER OF GLABRA3 (EGL3), two closely related bHLH proteins, are required for the action of the overexpressed WER and that WER interacts with these bHLHs in plant cells. Furthermore, we find that CPC suppresses the WER overexpression phenotype quantitatively. These results show that WER acts together with GL3/EGL3 to induce GL2 expression and that WER and CPC compete with one another to define cell fates in the Arabidopsis root epidermis.

The Role of Cytokinin During Infection of Arabidopsis thaliana by the Cyst Nematode Heterodera schachtii.

PubMed

Shanks, Carly M; Rice, J Hollis; Zubo, Yan; Schaller, G Eric; Hewezi, Tarek; Kieber, Joseph J

2016-01-01

Plant-parasitic cyst nematodes induce the formation of hypermetabolic feeding sites, termed syncytia, as their sole source of nutrients. The formation of the syncytium is orchestrated by the nematode, in part, by modulation of phytohormone responses, including cytokinin. In response to infection by the nematode Heterodera schachtii, cytokinin signaling is transiently induced at the site of infection and in the developing syncytium. Arabidopsis lines with reduced cytokinin sensitivity show reduced susceptibility to nematode infection, indicating that cytokinin signaling is required for optimal nematode development. Furthermore, lines with increased cytokinin sensitivity also exhibit reduced nematode susceptibility. To ascertain why cytokinin hypersensitivity reduces nematode parasitism, we examined the transcriptomes in wild type and a cytokinin-hypersensitive type-A arr Arabidopsis mutant in response to H. schachtii infection. Genes involved in the response to biotic stress and defense response were elevated in the type-A arr mutant in the absence of nematodes and were hyperinduced following H. schachtii infection, which suggests that the Arabidopsis type-A arr mutants impede nematode development because they are primed to respond to pathogen infection. These results suggest that cytokinin signaling is required for optimal H. schachtii parasitism of Arabidopsis but that elevated cytokinin signaling triggers a heightened immune response to nematode infection.

Transcription Factor Arabidopsis Activating Factor1 Integrates Carbon Starvation Responses with Trehalose Metabolism1[OPEN

PubMed Central

Garapati, Prashanth; Feil, Regina; Lunn, John Edward; Van Dijck, Patrick; Balazadeh, Salma; Mueller-Roeber, Bernd

2015-01-01

Plants respond to low carbon supply by massive reprogramming of the transcriptome and metabolome. We show here that the carbon starvation-induced NAC (for NO APICAL MERISTEM/ARABIDOPSIS TRANSCRIPTION ACTIVATION FACTOR/CUP-SHAPED COTYLEDON) transcription factor Arabidopsis (Arabidopsis thaliana) Transcription Activation Factor1 (ATAF1) plays an important role in this physiological process. We identified TREHALASE1, the only trehalase-encoding gene in Arabidopsis, as a direct downstream target of ATAF1. Overexpression of ATAF1 activates TREHALASE1 expression and leads to reduced trehalose-6-phosphate levels and a sugar starvation metabolome. In accordance with changes in expression of starch biosynthesis- and breakdown-related genes, starch levels are generally reduced in ATAF1 overexpressors but elevated in ataf1 knockout plants. At the global transcriptome level, genes affected by ATAF1 are broadly associated with energy and carbon starvation responses. Furthermore, transcriptional responses triggered by ATAF1 largely overlap with expression patterns observed in plants starved for carbon or energy supply. Collectively, our data highlight the existence of a positively acting feedforward loop between ATAF1 expression, which is induced by carbon starvation, and the depletion of cellular carbon/energy pools that is triggered by the transcriptional regulation of downstream gene regulatory networks by ATAF1. PMID:26149570

A Large Complement of the Predicted Arabidopsis ARM Repeat Proteins Are Members of the U-Box E3 Ubiquitin Ligase Family1[w

PubMed Central

Mudgil, Yashwanti; Shiu, Shin-Han; Stone, Sophia L.; Salt, Jennifer N.; Goring, Daphne R.

2004-01-01

The Arabidopsis genome was searched to identify predicted proteins containing armadillo (ARM) repeats, a motif known to mediate protein-protein interactions in a number of different animal proteins. Using domain database predictions and models generated in this study, 108 Arabidopsis proteins were identified that contained a minimum of two ARM repeats with the majority of proteins containing four to eight ARM repeats. Clustering analysis showed that the 108 predicted Arabidopsis ARM repeat proteins could be divided into multiple groups with wide differences in their domain compositions and organizations. Interestingly, 41 of the 108 Arabidopsis ARM repeat proteins contained a U-box, a motif present in a family of E3 ligases, and these proteins represented the largest class of Arabidopsis ARM repeat proteins. In 14 of these U-box/ARM repeat proteins, there was also a novel conserved domain identified in the N-terminal region. Based on the phylogenetic tree, representative U-box/ARM repeat proteins were selected for further study. RNA-blot analyses revealed that these U-box/ARM proteins are expressed in a variety of tissues in Arabidopsis. In addition, the selected U-box/ARM proteins were found to be functional E3 ubiquitin ligases. Thus, these U-box/ARM proteins represent a new family of E3 ligases in Arabidopsis. PMID:14657406

Multilocus Patterns of Nucleotide Diversity, Population Structure and Linkage Disequilibrium in Boechera stricta, a Wild Relative of Arabidopsis

PubMed Central

Song, Bao-Hua; Windsor, Aaron J.; Schmid, Karl J.; Ramos-Onsins, Sebastian; Schranz, M. Eric; Heidel, Andrew J.; Mitchell-Olds, Thomas

2009-01-01

Information about polymorphism, population structure, and linkage disequilibrium (LD) is crucial for association studies of complex trait variation. However, most genomewide studies have focused on model systems, with very few analyses of undisturbed natural populations. Here, we sequenced 86 mapped nuclear loci for a sample of 46 genotypes of Boechera stricta and two individuals of B. holboellii, both wild relatives of Arabidopsis. Isolation by distance was significant across the species range of B. stricta, and three geographic groups were identified by structure analysis, principal coordinates analysis, and distance-based phylogeny analyses. The allele frequency spectrum indicated a genomewide deviation from an equilibrium neutral model, with silent nucleotide diversity averaging 0.004. LD decayed rapidly, declining to background levels in ∼10 kb or less. For tightly linked SNPs separated by <1 kb, LD was dependent on the reference population. LD was lower in the specieswide sample than within populations, suggesting that low levels of LD found in inbreeding species such as B. stricta, Arabidopsis thaliana, and barley may result from broad geographic sampling that spans heterogeneous genetic groups. Finally, analyses also showed that inbreeding B. stricta and A. thaliana have ∼45% higher recombination per kilobase than outcrossing A. lyrata. PMID:19104077

Development of multi-metal interaction model for Daphnia magna: Significance of metallothionein in cellular redistribution.

PubMed

Wang, Xiangrui; Liu, Jianyu; Tan, Qiaoguo; Ren, Jinqian; Liang, Dingyuan; Fan, Wenhong

2018-04-30

Despite the great progress made in metal-induced toxicity mechanisms, a critical knowledge gap still exists in predicting adverse effects of heavy metals on living organisms in the natural environment, particularly during exposure to multi-metals. In this study, a multi-metal interaction model of Daphnia manga was developed in an effort to provide reasonable explanations regarding the joint effects resulting from exposure to multi-metals. Metallothionein (MT), a widely used biomarker, was selected. In this model, MT was supposed to play the role of a crucial transfer protein rather than detoxifying protein. Therefore, competitive complexation of metals to MT could highly affect the cellular metal redistribution. Thus, competitive complexation of MT in D. magna with metals like Pb 2+ , Cd 2+ and Cu 2+ was qualitatively studied. The results suggested that Cd 2+ had the highest affinity towards MT, followed by Pb 2+ and Cu 2+ . On the other hand, the combination of MT with Cu 2+ appeared to alter its structure which resulted in higher affinity towards Pb 2+ . Overall, the predicted bioaccumulation of metals under multi-metal exposure was consisted with earlier reported studies. This model provided an alternative angle for joint effect through a combination of kinetic process and internal interactions, which could help to develop future models predicting toxicity to multi-metal exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

Prevention of gastrointestinal lead poisoning using recombinant Lactococcus lactis expressing human metallothionein-I fusion protein.

PubMed

Xiao, Xue; Zhang, Changbin; Liu, Dajun; Bai, Weibin; Zhang, Qihao; Xiang, Qi; Huang, Yadong; Su, Zhijian

2016-04-05

Low-level lead poisoning is an insidious disease that affects millions of children worldwide, leading to biochemical and neurological dysfunctions. Blocking lead uptake via the gastrointestinal tract is an important prevention strategy. With this in mind, we constructed the recombinant Lactococcus lactis strain pGSMT/MG1363, which constitutively expressed the fusion protein glutathione S-transferase (GST)-small molecule ubiquitin-like modifier protein (SUMO)-metallothionein-I (GST-SUMO-MT). The thermodynamic data indicated that the average number of lead bound to a GST-SUMO-MT molecule was 3.655 and this binding reaction was a spontaneous, exothermic and entropy-increasing process. The total lead-binding capacity of pGSMT/MG1363 was 4.11 ± 0.15 mg/g dry mass. Oral administration of pGSMT/MG1363 (1 × 10(10) Colony-Forming Units) to pubertal male rats that were also treated with 5 mg/kg of lead acetate daily significantly inhibited the increase of blood lead levels, the impairment of hepatic function and the decrease of testosterone concentration in the serum, which were all impaired in rats treated by lead acetate alone. Moreover, the administration of pGSMT/MG1363 for 6 weeks did not affect the serum concentration of calcium, magnesium, potassium or sodium ions. This study provides a convenient and economical biomaterial for preventing lead poisoning via the digestive tract.

The HSP terminator of Arabidopsis thaliana increases gene expression in plant cells.

PubMed

Nagaya, Shingo; Kawamura, Kazue; Shinmyo, Atsuhiko; Kato, Ko

2010-02-01

To express a foreign gene in plants effectively, a good expression system is required. Here we describe the identification of a transcriptional terminator that supports increased levels of expression. The terminators of several Arabidopsis genes were examined in transfected Arabidopsis T87 protoplasts. The heat shock protein 18.2 (HSP) terminator was the most effective in supporting increased levels of expression. The HSP terminator increases mRNA levels of both transiently and stably expressed transgenes approximately 2-fold more than the NOS (nopaline synthase) terminator. When combined with the HSP terminator, a translational enhancer increased gene expression levels approximately 60- to 100-fold in transgenic plants.

The Multinational Arabidopsis Steering Subcommittee for Proteomics Assembles the Largest Proteome Database Resource for Plant Systems Biology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weckwerth, Wolfram; Baginsky, Sacha; Van Wijk, Klass

2009-12-01

In the past 10 years, we have witnessed remarkable advances in the field of plant molecular biology. The rapid development of proteomic technologies and the speed with which these techniques have been applied to the field have altered our perception of how we can analyze proteins in complex systems. At nearly the same time, the availability of the complete genome for the model plant Arabidopsis thaliana was released; this effort provides an unsurpassed resource for the identification of proteins when researchers use MS to analyze plant samples. Recognizing the growth in this area, the Multinational Arabidopsis Steering Committee (MASC) establishedmore » a subcommittee for A. thaliana proteomics in 2006 with the objective of consolidating databases, technique standards, and experimentally validated candidate genes and functions. Since the establishment of the Multinational Arabidopsis Steering Subcommittee for Proteomics (MASCP), many new approaches and resources have become available. Recently, the subcommittee established a webpage to consolidate this information (www.masc-proteomics.org). It includes links to plant proteomic databases, general information about proteomic techniques, meeting information, a summary of proteomic standards, and other relevant resources. Altogether, this website provides a useful resource for the Arabidopsis proteomics community. In the future, the website will host discussions and investigate the cross-linking of databases. The subcommittee members have extensive experience in arabidopsis proteomics and collectively have produced some of the most extensive proteomics data sets for this model plant (Table S1 in the Supporting Information has a list of resources). The largest collection of proteomics data from a single study in A. thaliana was assembled into an accessible database (AtProteome; http://fgcz-atproteome.unizh.ch/index.php) and was recently published by the Baginsky lab.1 The database provides links to major Arabidopsis

Calcium mobilizations in response to changes in the gravity vector in Arabidopsis seedlings

PubMed Central

Tatsumi, Hitoshi; Toyota, Masatsugu; Furuichi, Takuya; Sokabe, Masahiro

2014-01-01

Gravity influences the growth direction of higher plants. Changes in the gravity vector (gravistimulation) immediately promote the increase in the cytoplasmic free calcium ion concentration ([Ca2+]c) in Arabidopsis (Arabidopsis thaliana) seedlings. When the seedlings are gravistimulated by reorientation at 180°, a transient two peaked (biphasic) [Ca2+]c-increase arises in their hypocotyl and petioles. Parabolic flights (PFs) can generate a variety of gravity-stimuli, and enables us to measure gravity-induced [Ca2+]c-increases without specimen rotation, which demonstrate that Arabidopsis seedlings possess a rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes into Ca2+ signals on a sub-second timescale. Hypergravity by centrifugation (20 g or 300 g) also induces similar transient [Ca2+]c-increases. In this review, we propose models for possible cellular processes of the garavi-stimulus-induced [Ca2+]c-increase, and evaluate those by examining whether the model fits well with the kinetic parameters derived from the [Ca2+]c-increases obtained by applying gravistimulus with different amplitudes and time sequences. PMID:25763612

RABBIT EARS regulates the transcription of TCP4 during petal development in Arabidopsis.

PubMed

Li, Jing; Wang, Yanzhi; Zhang, Yongxia; Wang, Weiyao; Irish, Vivian F; Huang, Tengbo

2016-12-01

Plant organ growth requires the proper transition from cell proliferation to cell expansion and differentiation. The CIN-TCP transcription factor gene TCP4 and its post-transcriptional regulator microRNA319 play a pivotal role in this process. In this study, we identified a pathway in which the product of the C2H2 zinc finger gene RABBIT EARS (RBE) regulates the transcription of TCP4 during Arabidopsis (Arabidopsis thaliana) petal development. RBE directly represses TCP4 during the early stages of petal development; this contributes to the role of RBE in controlling the growth of petal primordia. We also found that the rbe-1 mutant strongly enhanced the petal phenotypes of tcp4soj6 and mir319a, two mutants with compromised miR319 regulation of TCP4 Our results show that transcriptional and post-transcriptional regulation function together to pattern the spatial and temporal expression of TCP4 This in turn controls petal size and shape in Arabidopsis. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

TORNADO1 regulates root epidermal patterning through the WEREWOLF pathway in Arabidopsis thaliana.

PubMed

Kwak, Su-Hwan; Song, Sang-Kee; Lee, Myeong Min; Schiefelbein, John

2015-01-01

Cell fate in the root epidermis of Arabidopsis thaliana is determined in a position-dependent manner. SCRAMBLED (SCM), an atypical leucine-rich repeat receptor-like kinase, mediates this positional regulation via its effect on WEREWOLF (WER) expression, and subsequently, its downstream transcription factor, GLABRA2 (GL2), which are required for nonhair cell development. Previously, TORNADO1 (TRN1), a plant-specific protein with a leucine-rich repeat ribonuclease inhibitor-like domain, was shown to be required for proper epidermal patterning in Arabidopsis roots. In this work, we analyzed the possible involvement of TRN1 in the known root epidermal gene network. We discovered that the trn1 mutant caused the ectopic expression of WER and the randomized expression of GL2 and EGL3. This suggests that TRN1 regulates the position-dependent cell fate determination by affecting WER expression in Arabidopsis root epidermis. Additionally, the distinct phenotypes of the aerial parts of the trn1-t and scm-2 mutant suggest that TRN1 and SCM might have different functions in the development of aerial parts.

TORNADO1 regulates root epidermal patterning through the WEREWOLF pathway in Arabidopsis thaliana

PubMed Central

Kwak, Su-Hwan; Song, Sang-Kee; Lee, Myeong Min; Schiefelbein, John

2015-01-01

Cell fate in the root epidermis of Arabidopsis thaliana is determined in a position-dependent manner. SCRAMBLED (SCM), an atypical leucine-rich repeat receptor-like kinase, mediates this positional regulation via its effect on WEREWOLF (WER) expression, and subsequently, its downstream transcription factor, GLABRA2 (GL2), which are required for nonhair cell development. Previously, TORNADO1 (TRN1), a plant-specific protein with a leucine-rich repeat ribonuclease inhibitor-like domain, was shown to be required for proper epidermal patterning in Arabidopsis roots. In this work, we analyzed the possible involvement of TRN1 in the known root epidermal gene network. We discovered that the trn1 mutant caused the ectopic expression of WER and the randomized expression of GL2 and EGL3. This suggests that TRN1 regulates the position-dependent cell fate determination by affecting WER expression in Arabidopsis root epidermis. Additionally, the distinct phenotypes of the aerial parts of the trn1-t and scm-2 mutant suggest that TRN1 and SCM might have different functions in the development of aerial parts. PMID:26451798

VIP1 is very important/interesting protein 1 regulating touch responses of Arabidopsis.

PubMed

Tsugama, Daisuke; Liu, Shenkui; Takano, Tetsuo

2016-06-02

VIP1 (VIRE2-INTERACTING PROTEIN 1) is a bZIP transcription factor in Arabidopsis thaliana. VIP1 and its close homologs (i.e., Arabidopsis group I bZIP proteins) are present in the cytoplasm under steady conditions, but are transiently localized to the nucleus when cells are exposed to hypo-osmotic conditions, which mimic mechanical stimuli such as touch. Recently we have reported that overexpression of a repression domain-fused form of VIP1 represses the expression of some touch-responsive genes, changes structures and/or local auxin responses of the root cap cells, and enhances the touch-induced root waving. This raises the possibility that VIP1 suppresses touch-induced responses. VIP1 should be useful to further characterize touch responses of plants. Here we discuss 2 seemingly interesting perspectives about VIP1: (1) What factors are involved in regulating the nuclear localization of VIP1?; (2) What can be done to further characterize the physiological functions of VIP1 and other Arabidopsis group I bZIP proteins?

Ectopic expression of Arabidopsis glutaredoxin gene AtGRXS17 in tomato (Solanum lycopersicum) confers tolerance to chilling stress

USDA-ARS?s Scientific Manuscript database

The monothiol glutaredoxin AtGRXS17 from "Arabidopsis" confers thermotolerance in yeast, "Arabidopsis", and tomato plants. Here, we report that AtGRXS17 also enhances tolerance to chilling stress in tomato and is associated with elevation of antioxidant enzyme activities, which are known to be invol...

Involvement of STH7 in light-adapted development in Arabidopsis thaliana promoted by both strigolactone and karrikin.

PubMed

Thussagunpanit, Jutiporn; Nagai, Yuko; Nagae, Miyu; Mashiguchi, Kiyoshi; Mitsuda, Nobutaka; Ohme-Takagi, Masaru; Nakano, Takeshi; Nakamura, Hidemitsu; Asami, Tadao

2017-02-01

Strigolactones (SLs) and karrikins (KARs) regulate photomorphogenesis. GR24, a synthetic SL and KAR 1 , a KAR, inhibit the hypocotyl elongation of Arabidopsis thaliana in a weak light. GR24 and KAR 1 up-regulate the expression of STH7, encoding a transcription factor belonging to the double B-box zinc finger subfamily. In this study, we used STH7-overexpressing (STH7ox) lines and functionally defective STH7 (STH7-SRDX) mutants to investigate roles of SLs and KARs in photomorphogenesis of Arabidopsis. Hypocotyl elongation of STH7-SRDX mutants was less sensitive to both GR24 and KAR 1 treatment than that of wild-type Arabidopsis under weak light conditions. Furthermore, the chlorophyll and anthocyanin content was increased in STH7ox lines when de-etiolated with light and GR24-treated plants had enhanced anthocyanin production. GR24 and KAR 1 treatment significantly increased the expression level of photosynthesis-related genes LHCB1 and rbcS. The results strongly suggest that SL and KAR induce photomorphogenesis of Arabidopsis in an STH7-dependent manner.

A transcriptomic study reveals differentially expressed genes and pathways respond to simulated acid rain in Arabidopsis thaliana.

PubMed

Liu, Ting-Wu; Niu, Li; Fu, Bin; Chen, Juan; Wu, Fei-Hua; Chen, Juan; Wang, Wen-Hua; Hu, Wen-Jun; He, Jun-Xian; Zheng, Hai-Lei

2013-01-01

Acid rain, as a worldwide environmental issue, can cause serious damage to plants. In this study, we provided the first case study on the systematic responses of arabidopsis (Arabidopsis thaliana (L.) Heynh.) to simulated acid rain (SiAR) by transcriptome approach. Transcriptomic analysis revealed that the expression of a set of genes related to primary metabolisms, including nitrogen, sulfur, amino acid, photosynthesis, and reactive oxygen species metabolism, were altered under SiAR. In addition, transport and signal transduction related pathways, especially calcium-related signaling pathways, were found to play important roles in the response of arabidopsis to SiAR stress. Further, we compared our data set with previously published data sets on arabidopsis transcriptome subjected to various stresses, including wound, salt, light, heavy metal, karrikin, temperature, osmosis, etc. The results showed that many genes were overlapped in several stresses, suggesting that plant response to SiAR is a complex process, which may require the participation of multiple defense-signaling pathways. The results of this study will help us gain further insights into the response mechanisms of plants to acid rain stress.

Small RNA Deep Sequencing and the Effects of microRNA408 on Root Gravitropic Bending in Arabidopsis

NASA Astrophysics Data System (ADS)

Li, Huasheng; Lu, Jinying; Sun, Qiao; Chen, Yu; He, Dacheng; Liu, Min

2015-11-01

MicroRNA (miRNA) is a non-coding small RNA composed of 20 to 24 nucleotides that influences plant root development. This study analyzed the miRNA expression in Arabidopsis root tip cells using Illumina sequencing and real-time PCR before (sample 0) and 15 min after (sample 15) a 3-D clinostat rotational treatment was administered. After stimulation was performed, the expression levels of seven miRNA genes, including Arabidopsis miR160, miR161, miR394, miR402, miR403, miR408, and miR823, were significantly upregulated. Illumina sequencing results also revealed two novel miRNAsthat have not been previously reported, The target genes of these miRNAs included pentatricopeptide repeat-containing protein and diadenosine tetraphosphate hydrolase. An overexpression vector of Arabidopsis miR408 was constructed and transferred to Arabidopsis plant. The roots of plants over expressing miR408 exhibited a slower reorientation upon gravistimulation in comparison with those of wild-type. This result indicate that miR408 could play a role in root gravitropic response.

Bicarbonate Induced Redox Proteome Changes in Arabidopsis Suspension Cells.

PubMed

Yin, Zepeng; Balmant, Kelly; Geng, Sisi; Zhu, Ning; Zhang, Tong; Dufresne, Craig; Dai, Shaojun; Chen, Sixue

2017-01-01

Climate change as a result of increasing atmospheric CO 2 affects plant growth and productivity. CO 2 is not only a carbon donor for photosynthesis but also an environmental signal that can perturb cellular redox homeostasis and lead to modifications of redox-sensitive proteins. Although redox regulation of protein functions has emerged as an important mechanism in several biological processes, protein redox modifications and how they function in plant CO 2 response remain unclear. Here a new iodoTMTRAQ proteomics technology was employed to analyze changes in protein redox modifications in Arabidopsis thaliana suspension cells in response to bicarbonate (mimic of elevated CO 2 ) in a time-course study. A total of 47 potential redox-regulated proteins were identified with functions in carbohydrate and energy metabolism, transport, ROS scavenging, cell structure modulation and protein turnover. This inventory of previously unknown redox responsive proteins in Arabidopsis bicarbonate responses lays a foundation for future research toward understanding the molecular mechanisms underlying plant CO 2 responses.

Bicarbonate Induced Redox Proteome Changes in Arabidopsis Suspension Cells

PubMed Central

Yin, Zepeng; Balmant, Kelly; Geng, Sisi; Zhu, Ning; Zhang, Tong; Dufresne, Craig; Dai, Shaojun; Chen, Sixue

2017-01-01

Climate change as a result of increasing atmospheric CO2 affects plant growth and productivity. CO2 is not only a carbon donor for photosynthesis but also an environmental signal that can perturb cellular redox homeostasis and lead to modifications of redox-sensitive proteins. Although redox regulation of protein functions has emerged as an important mechanism in several biological processes, protein redox modifications and how they function in plant CO2 response remain unclear. Here a new iodoTMTRAQ proteomics technology was employed to analyze changes in protein redox modifications in Arabidopsis thaliana suspension cells in response to bicarbonate (mimic of elevated CO2) in a time-course study. A total of 47 potential redox-regulated proteins were identified with functions in carbohydrate and energy metabolism, transport, ROS scavenging, cell structure modulation and protein turnover. This inventory of previously unknown redox responsive proteins in Arabidopsis bicarbonate responses lays a foundation for future research toward understanding the molecular mechanisms underlying plant CO2 responses. PMID:28184230

Tissue specific specialization of the nanoscale architecture of Arabidopsis.

PubMed

Liu, Jiliang; Inouye, Hideyo; Venugopalan, Nagarajan; Fischetti, Robert F; Gleber, S Charlotte; Vogt, Stefan; Cusumano, Joanne C; Kim, Jeong Im; Chapple, Clint; Makowski, Lee

2013-11-01

The Arabidopsis stem is composed of five tissues - the pith, xylem, phloem, cortex and epidermis - each of which fulfills specific roles in support of the growth and survival of the organism. The lignocellulosic scaffolding of cell walls is specialized to provide optimal support for the diverse functional roles of these layers, but little is known about this specialization. X-ray scattering can be used to study this tissue-specific diversity because the cellulosic components of the cell walls give rise to recognizable scattering features interpretable in terms of the underlying molecular architecture and distinct from the largely unoriented scatter from other constituents. Here we use scanning X-ray microdiffraction from thin sections to characterize the diversity of molecular architecture in the Arabidopsis stem and correlate that diversity to the functional roles the distinct tissues of the stem play in the growth and survival of the organism. Copyright © 2013. Published by Elsevier Inc.

Abscisic Acid (ABA) Regulation of Arabidopsis SR Protein Gene Expression

PubMed Central

Cruz, Tiago M. D.; Carvalho, Raquel F.; Richardson, Dale N.; Duque, Paula

2014-01-01

Serine/arginine-rich (SR) proteins are major modulators of alternative splicing, a key generator of proteomic diversity and flexible means of regulating gene expression likely to be crucial in plant environmental responses. Indeed, mounting evidence implicates splicing factors in signal transduction of the abscisic acid (ABA) phytohormone, which plays pivotal roles in the response to various abiotic stresses. Using real-time RT-qPCR, we analyzed total steady-state transcript levels of the 18 SR and two SR-like genes from Arabidopsis thaliana in seedlings treated with ABA and in genetic backgrounds with altered expression of the ABA-biosynthesis ABA2 and the ABA-signaling ABI1 and ABI4 genes. We also searched for ABA-responsive cis elements in the upstream regions of the 20 genes. We found that members of the plant-specific SC35-Like (SCL) Arabidopsis SR protein subfamily are distinctively responsive to exogenous ABA, while the expression of seven SR and SR-related genes is affected by alterations in key components of the ABA pathway. Finally, despite pervasiveness of established ABA-responsive promoter elements in Arabidopsis SR and SR-like genes, their expression is likely governed by additional, yet unidentified cis-acting elements. Overall, this study pinpoints SR34, SR34b, SCL30a, SCL28, SCL33, RS40, SR45 and SR45a as promising candidates for involvement in ABA-mediated stress responses. PMID:25268622

Structure and Function of Centromeric and Pericentromeric Heterochromatin in Arabidopsis thaliana.

PubMed

Simon, Lauriane; Voisin, Maxime; Tatout, Christophe; Probst, Aline V

2015-01-01

The centromere is a specific chromosomal region where the kinetochore assembles to ensure the faithful segregation of sister chromatids during mitosis and meiosis. Centromeres are defined by a local enrichment of the specific histone variant CenH3 mostly at repetitive satellite sequences. A larger pericentromeric region containing repetitive sequences and transposable elements surrounds the centromere that adopts a particular chromatin state characterized by specific histone variants and post-translational modifications and forms a transcriptionally repressive chromosomal environment. In the model organism Arabidopsis thaliana centromeric and pericentromeric domains form conspicuous heterochromatin clusters called chromocenters in interphase. Here we discuss, using Arabidopsis as example, recent insight into mechanisms involved in maintenance and establishment of centromeric and pericentromeric chromatin signatures as well as in chromocenter formation.

Ectopic Expression of Pumpkin Gibberellin Oxidases Alters Gibberellin Biosynthesis and Development of Transgenic Arabidopsis Plants1

PubMed Central

Radi, Abeer; Lange, Theo; Niki, Tomoya; Koshioka, Masaji; Lange, Maria João Pimenta

2006-01-01

Immature pumpkin (Cucurbita maxima) seeds contain gibberellin (GA) oxidases with unique catalytic properties resulting in GAs of unknown function for plant growth and development. Overexpression of pumpkin GA 7-oxidase (CmGA7ox) in Arabidopsis (Arabidopsis thaliana) resulted in seedlings with elongated roots, taller plants that flower earlier with only a little increase in bioactive GA4 levels compared to control plants. In the same way, overexpression of the pumpkin GA 3-oxidase1 (CmGA3ox1) resulted in a GA overdose phenotype with increased levels of endogenous GA4. This indicates that, in Arabidopsis, 7-oxidation and 3-oxidation are rate-limiting steps in GA plant hormone biosynthesis that control plant development. With an opposite effect, overexpression of pumpkin seed-specific GA 20-oxidase1 (CmGA20ox1) in Arabidopsis resulted in dwarfed plants that flower late with reduced levels of GA4 and increased levels of physiological inactive GA17 and GA25 and unexpected GA34 levels. Severe dwarfed plants were obtained by overexpression of the pumpkin GA 2-oxidase1 (CmGA2ox1) in Arabidopsis. This dramatic change in phenotype was accompanied by a considerable decrease in the levels of bioactive GA4 and an increase in the corresponding inactivation product GA34 in comparison to control plants. In this study, we demonstrate the potential of four pumpkin GA oxidase-encoding genes to modulate the GA plant hormone pool and alter plant stature and development. PMID:16384902

An improved, low-cost, hydroponic system for growing Arabidopsis and other plant species under aseptic conditions

PubMed Central

2014-01-01

Background Hydroponics is a plant growth system that provides a more precise control of growth media composition. Several hydroponic systems have been reported for Arabidopsis and other model plants. The ease of system set up, cost of the growth system and flexibility to characterize and harvest plant material are features continually improved in new hydroponic system reported. Results We developed a hydroponic culture system for Arabidopsis and other model plants. This low cost, proficient, and novel system is based on recyclable and sterilizable plastic containers, which are readily available from local suppliers. Our system allows a large-scale manipulation of seedlings. It adapts to different growing treatments and has an extended growth window until adult plants are established. The novel seed-holder also facilitates the transfer and harvest of seedlings. Here we report the use of our hydroponic system to analyze transcriptomic responses of Arabidopsis to nutriment availability and plant/pathogen interactions. Conclusions The efficiency and functionality of our proposed hydroponic system is demonstrated in nutrient deficiency and pathogenesis experiments. Hydroponically grown Arabidopsis seedlings under long-time inorganic phosphate (Pi) deficiency showed typical changes in root architecture and high expression of marker genes involved in signaling and Pi recycling. Genome-wide transcriptional analysis of gene expression of Arabidopsis roots depleted of Pi by short time periods indicates that genes related to general stress are up-regulated before those specific to Pi signaling and metabolism. Our hydroponic system also proved useful for conducting pathogenesis essays, revealing early transcriptional activation of pathogenesis-related genes. PMID:24649917

An improved, low-cost, hydroponic system for growing Arabidopsis and other plant species under aseptic conditions.

PubMed

Alatorre-Cobos, Fulgencio; Calderón-Vázquez, Carlos; Ibarra-Laclette, Enrique; Yong-Villalobos, Lenin; Pérez-Torres, Claudia-Anahí; Oropeza-Aburto, Araceli; Méndez-Bravo, Alfonso; González-Morales, Sandra-Isabel; Gutiérrez-Alanís, Dolores; Chacón-López, Alejandra; Peña-Ocaña, Betsy-Anaid; Herrera-Estrella, Luis

2014-03-21

Hydroponics is a plant growth system that provides a more precise control of growth media composition. Several hydroponic systems have been reported for Arabidopsis and other model plants. The ease of system set up, cost of the growth system and flexibility to characterize and harvest plant material are features continually improved in new hydroponic system reported. We developed a hydroponic culture system for Arabidopsis and other model plants. This low cost, proficient, and novel system is based on recyclable and sterilizable plastic containers, which are readily available from local suppliers. Our system allows a large-scale manipulation of seedlings. It adapts to different growing treatments and has an extended growth window until adult plants are established. The novel seed-holder also facilitates the transfer and harvest of seedlings. Here we report the use of our hydroponic system to analyze transcriptomic responses of Arabidopsis to nutriment availability and plant/pathogen interactions. The efficiency and functionality of our proposed hydroponic system is demonstrated in nutrient deficiency and pathogenesis experiments. Hydroponically grown Arabidopsis seedlings under long-time inorganic phosphate (Pi) deficiency showed typical changes in root architecture and high expression of marker genes involved in signaling and Pi recycling. Genome-wide transcriptional analysis of gene expression of Arabidopsis roots depleted of Pi by short time periods indicates that genes related to general stress are up-regulated before those specific to Pi signaling and metabolism. Our hydroponic system also proved useful for conducting pathogenesis essays, revealing early transcriptional activation of pathogenesis-related genes.

Sodium Fluxes through Nonselective Cation Channels in the Plasma Membrane of Protoplasts from Arabidopsis Roots1

PubMed Central

Demidchik, Vadim; Tester, Mark

2002-01-01

The aim of the present work was to characterize Na+ currents through nonselective cation channels (NSCCs) in protoplasts derived from root cells of Arabidopsis. The procedure of the protoplast isolation was modified to increase the stability of Arabidopsis root protoplasts in low external Ca2+ by digesting tissue in elevated Ca2+. Experiments in whole-cell and outside-out modes were carried out. We found that Na+ currents in Arabidopsis root protoplasts were mediated by cation channels that were insensitive to externally applied tetraethylammonium+ and verapamil, had no time-dependent activation (permanently opened or completely activated within 1–2 ms), were voltage independent, and were weakly selective for monovalent cations. The selectivity sequence was as follows: K+ (1.49) > NH4+ (1.24) > Rb+ (1.15) ≈ Cs+ (1.10) ≈ Na+ (1.00) > Li+ (0.73) > tetraethylammonium+ (0.47). Arabidopsis root NSCCs were blocked by H+ (pK ≈ 6.0), Ca2+ (K1/2 ≈ 0.1 mm), Ba2+, Zn2+, La3+, Gd3+, quinine, and the His modifier diethylpyrocarbonate. They were insensitive to most organic blockers (nifedipine, verapamil, flufenamate, and amiloride) and to the SH-group modifier p-chloromercuriphenyl sulfonic acid. Voltage-insensitive, Ca2+-sensitive single channels were also resolved. Properties of Arabidopsis root NSCCs are discussed and compared with characteristics of similar conductances studied previously in plants and animals. It is suggested that NSCCs present a distinct group of plant ion channels, mediating toxic Na+ influx to the cell and probably having other important roles in physiological processes of plants. PMID:11842142

Arabidopsis thaliana polyamine content is modified by the interaction with different Trichoderma species.

PubMed

Salazar-Badillo, Fatima Berenice; Sánchez-Rangel, Diana; Becerra-Flora, Alicia; López-Gómez, Miguel; Nieto-Jacobo, Fernanda; Mendoza-Mendoza, Artemio; Jiménez-Bremont, Juan Francisco

2015-10-01

Plants are associated with a wide range of microorganisms throughout their life cycle, and some interactions result on plant benefits. Trichoderma species are plant beneficial fungi that enhance plant growth and development, contribute to plant nutrition and induce defense responses. Nevertheless, the molecules involved in these beneficial effects still need to be identify. Polyamines are ubiquitous molecules implicated in plant growth and development, and in the establishment of plant microbe interactions. In this study, we assessed the polyamine profile in Arabidopsis plants during the interaction with Trichoderma virens and Trichoderma atroviride, using a system that allows direct plant-fungal contact or avoids their physical interaction (split system). The plantlets that grew in the split system exhibited higher biomass than the ones in direct contact with Trichoderma species. After 3 days of interaction, a significant decrease in Arabidopsis polyamine levels was observed in both systems (direct contact and split). After 5 days of interaction polyamine levels were increased. The highest levels were observed with T. atroviride (split system), and with T. virens (direct contact). The expression levels of Arabidopsis ADC1 and ADC2 genes during the interaction with the fungi were also assessed. We observed a time dependent regulation of ADC1 and ADC2 genes, which correlates with polyamine levels. Our data show an evident change in polyamine profile during Arabidopsis - Trichoderma interaction, accompanied by evident alterations in plant root architecture. Polyamines could be involved in the changes undergone by plant during the interaction with this beneficial fungus. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Arabidopsis YAK1 regulates abscisic acid response and drought resistance.

PubMed

Kim, Dongjin; Ntui, Valentine Otang; Xiong, Liming

2016-07-01

Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. © 2016 Federation of European Biochemical Societies.

Arabidopsis Reduces Growth Under Osmotic Stress by Decreasing SPEECHLESS Protein

PubMed Central

Kumari, Archana; Jewaria, Pawan K.; Bergmann, Dominique C.; Kakimoto, Tatsuo

2014-01-01

Plants, which are sessile unlike most animals, have evolved a system to reduce growth under stress; however, the molecular mechanisms of this stress response are not well known. During programmed development, a fraction of the leaf epidermal precursor cells become meristemoid mother cells (MMCs), which are stem cells that produce both stomatal guard cells and epidermal pavement cells. Here we report that Arabidopsis plants, in response to osmotic stress, post-transcriptionally decrease the protein level of SPEECHLESS, the transcription factor promoting MMC identity, through the action of a mitogen-activated protein kinase (MAPK) cascade. The growth reduction under osmotic stress was lessened by inhibition of the MAPK cascade or by a mutation that disrupted the MAPK target amino acids in SPEECHLESS, indicating that Arabidopsis reduces growth under stress by integrating the osmotic stress signal into the MAPK–SPEECHLESS core developmental pathway. PMID:25381317

Altered gene expression changes in Arabidopsis leaf tissues and protoplasts in response to Plum pox virus infection

PubMed Central

Babu, Mohan; Griffiths, Jonathan S; Huang, Tyng-Shyan; Wang, Aiming

2008-01-01

Background Virus infection induces the activation and suppression of global gene expression in the host. Profiling gene expression changes in the host may provide insights into the molecular mechanisms that underlie host physiological and phenotypic responses to virus infection. In this study, the Arabidopsis Affymetrix ATH1 array was used to assess global gene expression changes in Arabidopsis thaliana plants infected with Plum pox virus (PPV). To identify early genes in response to PPV infection, an Arabidopsis synchronized single-cell transformation system was developed. Arabidopsis protoplasts were transfected with a PPV infectious clone and global gene expression changes in the transfected protoplasts were profiled. Results Microarray analysis of PPV-infected Arabidopsis leaf tissues identified 2013 and 1457 genes that were significantly (Q ≤ 0.05) up- (≥ 2.5 fold) and downregulated (≤ -2.5 fold), respectively. Genes associated with soluble sugar, starch and amino acid, intracellular membrane/membrane-bound organelles, chloroplast, and protein fate were upregulated, while genes related to development/storage proteins, protein synthesis and translation, and cell wall-associated components were downregulated. These gene expression changes were associated with PPV infection and symptom development. Further transcriptional profiling of protoplasts transfected with a PPV infectious clone revealed the upregulation of defence and cellular signalling genes as early as 6 hours post transfection. A cross sequence comparison analysis of genes differentially regulated by PPV-infected Arabidopsis leaves against uniEST sequences derived from PPV-infected leaves of Prunus persica, a natural host of PPV, identified orthologs related to defence, metabolism and protein synthesis. The cross comparison of genes differentially regulated by PPV infection and by the infections of other positive sense RNA viruses revealed a common set of 416 genes. These identified genes

Association of metallothionein-III with oligodendroglial cytoplasmic inclusions in multiple system atrophy.

PubMed

Pountney, D L; Dickson, T C; Power, J H T; Vickers, J C; West, A J; Gai, W P

2011-01-01

Multiple system atrophy (MSA) is an adult-onset neurodegenerative disease characterised by Parkinsonian and autonomic symptoms and by widespread intracytoplasmic inclusion bodies in oligodendrocytes. These glial cytoplasmic inclusions (GCIs) are comprised of 9-10 nm filaments rich in the protein alpha-synuclein, also found in neuronal inclusion bodies associated with Parkinson's disease. Metallothioneins (MTs) are a class of low-molecular weight (6-7 kDa), cysteine-rich metal-binding proteins the expression of which is induced by heavy metals, glucocorticoids, cytokines and oxidative stress. Recent studies have shown a role for the ubiquitously expressed MT-I/II isoforms in the brain following a variety of stresses, whereas, the function of the brain-specific MT isoform, MT-III, is less clear. MT-III and MT-I/II immunostaining of post-mortem tissue in MSA and normal control human brains showed that the number of MT-III-positive cells is significantly increased in MSA in visual cortex, whereas MT-I/II isoforms showed no significant difference in the distribution of immunopositive cells in MSA compared to normal tissue. GCIs were immunopositive for MT-III, but were immunonegative for the MT-I/II isoforms. Immunofluorescence double labelling showed the co-localisation of alpha-synuclein and MT-III in GCIs in MSA tissue. In isolated GCIs, transmission electron microscopy demonstrated MT-III immunogold labelling of the amorphous material surrounding alpha-synuclein filaments in GCIs. High-molecular weight MT-III species in addition to MT-III monomer were detected in GCIs by Western analysis of the detergent-solubilised proteins of purified GCIs. These results show that MT-III, but not MT-I/II, is a specific component of GCIs, present in abnormal aggregated forms external to the alpha-synuclein filaments.

Molecular actions of two synthetic brassinosteroids, iso-carbaBL and 6-deoxoBL, which cause altered physiological activities between Arabidopsis and rice

PubMed Central

Fujioka, Shozo; Ito, Shinsaku; Kigawa, Takanori; Shimada, Yukihisa; Matsuoka, Makoto; Yoshida, Shigeo; Kinoshita, Toshinori; Asami, Tadao; Seto, Hideharu; Nakano, Takeshi

2017-01-01

Brassinosteroid (BR) is an important plant hormone that is perceived by the BRASSINOSTEROID INSENSITIVE 1 (BRI1) receptor. BRI1 is conserved among dicot and monocot species; however, the molecular mechanism underlying BR perception in monocots is not fully understood. We synthesised two BRs, iso-carbabrassinolide (iso-carbaBL) and 6-deoxoBL, which have different BR activities in Arabidopsis thaliana (Arabidopsis) and rice. Our bioassay indicated that iso-carbaBL has relatively strong BR activity in Arabidopsis, but is inactive in rice and competitively inhibits BR activity. The bioactivity of 6-deoxoBL was similar to that of BL in Arabidopsis, but was much lower in rice. Binding experiments using recombinant Arabidopsis and rice BRI1 protein fragments suggested that iso-carbaBL and 6-deoxoBL bind to both receptors. These results showed that iso-carbaBL and 6-deoxoBL act as an antagonist and agonist, respectively, of BRs in rice. A docking simulation analysis suggested that iso-carbaBL fits deeper in the binding pocket to block the binding of active BR to rice BRI1. The simulated binding energy of 6-deoxoBL with rice BRI1 is much lower than that with Arabidopsis BRI1. The possible structural characteristics of rice BRI1 were determined based on the difference in the BR activities of iso-carbaBL and 6-deoxoBL in Arabidopsis and rice. PMID:28369122

Identification and Characterization of Arabidopsis Seed Coat Mucilage Proteins.

PubMed

Tsai, Allen Yi-Lun; Kunieda, Tadashi; Rogalski, Jason; Foster, Leonard J; Ellis, Brian E; Haughn, George W

2017-02-01

Plant cell wall proteins are important regulators of cell wall architecture and function. However, because cell wall proteins are difficult to extract and analyze, they are generally poorly understood. Here, we describe the identification and characterization of proteins integral to the Arabidopsis (Arabidopsis thaliana) seed coat mucilage, a specialized layer of the extracellular matrix composed of plant cell wall carbohydrates that is used as a model for cell wall research. The proteins identified in mucilage include those previously identified by genetic analysis, and several mucilage proteins are reduced in mucilage-deficient mutant seeds, suggesting that these proteins are genuinely associated with the mucilage. Arabidopsis mucilage has both nonadherent and adherent layers. Both layers have similar protein profiles except for proteins involved in lipid metabolism, which are present exclusively in the adherent mucilage. The most abundant mucilage proteins include a family of proteins named TESTA ABUNDANT1 (TBA1) to TBA3; a less abundant fourth homolog was named TBA-LIKE (TBAL). TBA and TBAL transcripts and promoter activities were detected in developing seed coats, and their expression requires seed coat differentiation regulators. TBA proteins are secreted to the mucilage pocket during differentiation. Although reverse genetics failed to identify a function for TBAs/TBAL, the TBA promoters are highly expressed and cell type specific and so should be very useful tools for targeting proteins to the seed coat epidermis. Altogether, these results highlight the mucilage proteome as a model for cell walls in general, as it shares similarities with other cell wall proteomes while also containing mucilage-specific features. © 2017 American Society of Plant Biologists. All Rights Reserved.

Potential role of Arabidopsis PHP as an accessory subunit of the PAF1 transcriptional cofactor.

PubMed

Park, Sunchung; Ek-Ramos, Maria Julissa; Oh, Sookyung; van Nocker, Steven

2011-08-01

Paf1C is a transcriptional cofactor that has been implicated in various transcription-associated mechanisms spanning initiation, elongation and RNA processing, and is important for multiple aspects of development in Arabidopsis. Our recent studies suggest Arabidopsis Paf1C is crucial for proper regulation of genes within H3K27me3-enriched chromatin, and that a protein named PHP may act as an accessory subunit of Paf1C that promotes this function.

Maize OXIDATIVE STRESS2 Homologs Enhance Cadmium Tolerance in Arabidopsis through Activation of a Putative SAM-Dependent Methyltransferase Gene.

PubMed

He, Lilong; Ma, Xiaoling; Li, Zhenzhen; Jiao, Zhengli; Li, Yongqing; Ow, David W

2016-07-01

Previously the Arabidopsis (Arabidopsis thaliana) zinc finger protein OXIDATIVE STRESS2 (AtOXS2) and four OXS2-like (AtO2L) family members were described to play a role in stress tolerance and stress escape. For stress escape, SOC1 was a target of AtOXS2. However, for stress tolerance, the downstream targets were not identified. We cloned two OXS2 homolog genes from sweet corn, ZmOXS2b and ZmO2L1 Both genes are transiently inducible by Cd treatment. When expressed in Arabidopsis, each enhances tolerance against cadmium. Further analysis showed that ZmOXS2b and ZmO2L1 proteins enhance Cd tolerance in Arabidopsis by activating at least one target gene, that encoding a putative S-adenosyl-l-Met-dependent methyltransferase superfamily protein (AT5G37990), which we named CIMT1 This activation involves the in vivo interaction with a segment of the CIMT1 promoter that contains a BOXS2 motif previously identified as the binding element for AtOXS2. More importantly, CIMT1 is induced by Cd treatment, and overexpression of this gene alone was sufficient to enhance Cd tolerance in Arabidopsis. The connection of ZmOXS2b and ZmO2L1 to Arabidopsis CIMT1 suggests a similar network may exist in maize (Zea mays) and may provide a clue to possibly using a CIMT1 maize homolog to engineer stress tolerance in a major crop. © 2016 American Society of Plant Biologists. All Rights Reserved.

The Identification of Maize and Arabidopsis Type I FLAVONE SYNTHASEs Links Flavones with Hormones and Biotic Interactions1[OPEN

PubMed Central

Falcone Ferreyra, María Lorena; Emiliani, Julia; Rodriguez, Eduardo José; Campos-Bermudez, Valeria Alina; Grotewold, Erich; Casati, Paula

2015-01-01

Flavones are a major group of flavonoids with diverse functions and are extensively distributed in land plants. There are two different classes of FLAVONE SYNTHASE (FNS) enzymes that catalyze the conversion of the flavanones into flavones. The FNSI class comprises soluble Fe2+/2-oxoglutarate-dependent dioxygenases, and FNSII enzymes are oxygen- and NADPH-dependent cytochrome P450 membrane-bound monooxygenases. Here, we describe the identification and characterization of FNSI enzymes from maize (Zea mays) and Arabidopsis (Arabidopsis thaliana). In maize, ZmFNSI-1 is expressed at significantly higher levels in silks and pericarps expressing the 3-deoxy flavonoid R2R3-MYB regulator P1, suggesting that ZmFNSI-1 could be the main enzyme for the synthesis of flavone O-glycosides. We also show here that DOWNY MILDEW RESISTANT6 (AtDMR6), the Arabidopsis homologous enzyme to ZmFNSI-1, has FNSI activity. While dmr6 mutants show loss of susceptibility to Pseudomonas syringae, transgenic dmr6 plants expressing ZmFNSI-1 show similar susceptibility to wild-type plants, demonstrating that ZmFNSI-1 can complement the mutant phenotype. AtDMR6 expression analysis showed a tissue- and developmental stage-dependent pattern, with high expression in cauline and senescing leaves. Finally, we show that Arabidopsis cauline and senescing leaves accumulate apigenin, demonstrating that Arabidopsis plants have an FNSI activity involved in the biosynthesis of flavones. The results presented here also suggest cross talk between the flavone and salicylic acid pathways in Arabidopsis; in this way, pathogens would induce flavones to decrease salicylic acid and, hence, increase susceptibility. PMID:26269546

A γ-Glutamyl Transpeptidase-Independent Pathway of Glutathione Catabolism to Glutamate via 5-Oxoproline in Arabidopsis1[W][OA

PubMed Central

Ohkama-Ohtsu, Naoko; Oikawa, Akira; Zhao, Ping; Xiang, Chengbin; Saito, Kazuki; Oliver, David J.

2008-01-01

The degradation pathway of glutathione (GSH) in plants is not well understood. In mammals, GSH is predominantly metabolized through the γ-glutamyl cycle, where GSH is degraded by the sequential reaction of γ-glutamyl transpeptidase (GGT), γ-glutamyl cyclotransferase, and 5-oxoprolinase to yield glutamate (Glu) and dipeptides that are subject to peptidase action. In this study, we examined if GSH is degraded through the same pathway in Arabidopsis (Arabidopsis thaliana) as occurs in mammals. In Arabidopsis, the oxoprolinase knockout mutants (oxp1-1 and oxp1-2) accumulate more 5-oxoproline (5OP) and less Glu than wild-type plants, suggesting substantial metabolite flux though 5OP and that 5OP is a major contributor to Glu steady-state levels. In the ggt1-1/ggt4-1/oxp1-1 triple mutant with no GGT activity in any organs except young siliques, the 5OP concentration in leaves was not different from that in oxp1-1, suggesting that GGTs are not major contributors to 5OP production in Arabidopsis. 5OP formation strongly tracked the level of GSH in Arabidopsis plants, suggesting that GSH is the precursor of 5OP in a GGT-independent reaction. Kinetics analysis suggests that γ-glutamyl cyclotransferase is the major source of GSH degradation and 5OP formation in Arabidopsis. This discovery led us to propose a new pathway for GSH turnover in plants where GSH is converted to 5OP and then to Glu by the combined action of γ-glutamyl cyclotransferase and 5-oxoprolinase in the cytoplasm. PMID:18768907

Chemical inhibition of a subset of Arabidopsis thaliana GSK3-like kinases activates brassinosteroid signaling.

PubMed

De Rybel, Bert; Audenaert, Dominique; Vert, Grégory; Rozhon, Wilfried; Mayerhofer, Juliane; Peelman, Frank; Coutuer, Silvie; Denayer, Tinneke; Jansen, Leentje; Nguyen, Long; Vanhoutte, Isabelle; Beemster, Gerrit T S; Vleminckx, Kris; Jonak, Claudia; Chory, Joanne; Inzé, Dirk; Russinova, Eugenia; Beeckman, Tom

2009-06-26

Glycogen synthase kinase 3 (GSK3) is a key regulator in signaling pathways in both animals and plants. Three Arabidopsis thaliana GSK3s are shown to be related to brassinosteroid (BR) signaling. In a phenotype-based compound screen we identified bikinin, a small molecule that activates BR signaling downstream of the BR receptor. Bikinin directly binds the GSK3 BIN2 and acts as an ATP competitor. Furthermore, bikinin inhibits the activity of six other Arabidopsis GSK3s. Genome-wide transcript analyses demonstrate that simultaneous inhibition of seven GSK3s is sufficient to activate BR responses. Our data suggest that GSK3 inhibition is the sole activation mode of BR signaling and argues against GSK3-independent BR responses in Arabidopsis. The opportunity to generate multiple and conditional knockouts in key regulators in the BR signaling pathway by bikinin represents a useful tool to further unravel regulatory mechanisms.

F-Box Protein FBX92 Affects Leaf Size in Arabidopsis thaliana

PubMed Central

Baute, Joke; Polyn, Stefanie; De Block, Jolien; Blomme, Jonas; Van Lijsebettens, Mieke

2017-01-01

F-box proteins are part of one of the largest families of regulatory proteins that play important roles in protein degradation. In plants, F-box proteins are functionally very diverse, and only a small subset has been characterized in detail. Here, we identified a novel F-box protein FBX92 as a repressor of leaf growth in Arabidopsis. Overexpression of AtFBX92 resulted in plants with smaller leaves than the wild type, whereas plants with reduced levels of AtFBX92 showed, in contrast, increased leaf growth by stimulating cell proliferation. Detailed cellular analysis suggested that AtFBX92 specifically affects the rate of cell division during early leaf development. This is supported by the increased expression levels of several cell cycle genes in plants with reduced AtFBX92 levels. Surprisingly, overexpression of the maize homologous gene ZmFBX92 in maize had no effect on plant growth, whereas ectopic expression in Arabidopsis increased leaf growth. Expression of a truncated form of AtFBX92 showed that the contrasting effects of ZmFBX92 and AtFBX92 gain of function in Arabidopsis are due to the absence of the F-box-associated domain in the ZmFBX92 gene. Our work reveals an additional player in the complex network that determines leaf size and lays the foundation for identifying putative substrates. PMID:28340173

Sugar suppresses cell death caused by disruption of fumarylacetoacetate hydrolase in Arabidopsis.

PubMed

Zhi, Tiantian; Zhou, Zhou; Huang, Yi; Han, Chengyun; Liu, Yan; Zhu, Qi; Ren, Chunmei

2016-09-01

Sugar negatively regulates cell death resulting from the loss of fumarylacetoacetate hydrolase that catalyzes the last step in the Tyr degradation pathway in Arabidopsis . Fumarylacetoacetate hydrolase (FAH) hydrolyzes fumarylacetoacetate to fumarate and acetoacetate, the final step in the tyrosine (Tyr) degradation pathway that is essential to animals. Previously, we first found that the Tyr degradation pathway plays an important role in plants. Mutation of the SSCD1 gene encoding FAH in Arabidopsis leads to spontaneous cell death under short-day conditions. In this study, we presented that the lethal phenotype of the short-day sensitive cell death1 (sscd1) seedlings was suppressed by sugars including sucrose, glucose, fructose, and maltose in a dose-dependent manner. Real-time quantitative PCR (RT-qPCR) analysis showed the expression of Tyr degradation pathway genes homogentisate dioxygenase and maleylacetoacetate isomerase, and sucrose-processing genes cell-wall invertase 1 and alkaline/neutral invertase G, was up-regulated in the sscd1 mutant, however, this up-regulation could be repressed by sugar. In addition, a high concentration of sugar attenuated cell death of Arabidopsis wild-type seedlings caused by treatment with exogenous succinylacetone, an abnormal metabolite resulting from the loss of FAH in the Tyr degradation pathway. These results indicated that (1) sugar could suppress cell death in sscd1, which might be because sugar supply enhances the resistance of Arabidopsis seedlings to toxic effects of succinylacetone and reduces the accumulation of Tyr degradation intermediates, resulting in suppression of cell death; and (2) sucrose-processing genes cell-wall invertase 1 and alkaline/neutral invertase G might be involved in the cell death in sscd1. Our work provides insights into the relationship between sugar and sscd1-mediated cell death, and contributes to elucidation of the regulation of cell death resulting from the loss of FAH in plants.

Overexpression of a citrus NDR1 ortholog increases disease resistance in Arabidopsis.

PubMed

Lu, Hua; Zhang, Chong; Albrecht, Ute; Shimizu, Rena; Wang, Guanfeng; Bowman, Kim D

2013-01-01

Emerging devastating diseases, such as Huanglongbing (HLB) and citrus canker, have caused tremendous losses to the citrus industry worldwide. Genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. The key to the success of this approach relies on a thorough understanding of defense mechanisms of citrus. Studies of Arabidopsis and other plants have provided a framework for us to better understand defense mechanisms of citrus. Salicylic acid (SA) is a key signaling molecule involved in basal defense and resistance (R) gene-mediated defense against broad-spectrum pathogens. The Arabidopsis gene NDR1 (NON-RACE-SPECIFIC DISEASE RESISTANCE 1) is a positive regulator of SA accumulation and is specifically required for signaling mediated by a subset of R genes upon recognition of their cognate pathogen effectors. Our bioinformatic analysis identified an ortholog of NDR1 from citrus, CsNDR1. Overexpression of CsNDR1 complemented susceptibility conferred by the Arabidopsis ndr1-1 mutant to Pseudomonas syringae strains and also led to enhanced resistance to an oomycete pathogen Hyaloperonospora arabidopsidis. Such heightened resistance is associated with increased SA production and expression of the defense marker gene PATHOGENESIS RELATED 1 (PR1). In addition, we found that expression of PR1 and accumulation of SA were induced to modest levels in citrus infected with Candidatus Liberibacter asiaticus, the bacterial pathogen associated with HLB disease. Thus, our data suggest that CsNDR1 is a functional ortholog of Arabidopsis NDR1. Since Ca. L. asiaticus infection only activates modest levels of defense responses in citrus, we propose that genetically increasing SA/NDR1-mediated pathways could potentially lead to enhanced resistance against HLB, citrus canker, and other destructive diseases challenging global citrus production.

Overexpression of a citrus NDR1 ortholog increases disease resistance in Arabidopsis

PubMed Central

Lu, Hua; Zhang, Chong; Albrecht, Ute; Shimizu, Rena; Wang, Guanfeng; Bowman, Kim D.

2013-01-01

Emerging devastating diseases, such as Huanglongbing (HLB) and citrus canker, have caused tremendous losses to the citrus industry worldwide. Genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. The key to the success of this approach relies on a thorough understanding of defense mechanisms of citrus. Studies of Arabidopsis and other plants have provided a framework for us to better understand defense mechanisms of citrus. Salicylic acid (SA) is a key signaling molecule involved in basal defense and resistance (R) gene-mediated defense against broad-spectrum pathogens. The Arabidopsis gene NDR1 (NON-RACE-SPECIFIC DISEASE RESISTANCE 1) is a positive regulator of SA accumulation and is specifically required for signaling mediated by a subset of R genes upon recognition of their cognate pathogen effectors. Our bioinformatic analysis identified an ortholog of NDR1 from citrus, CsNDR1. Overexpression of CsNDR1 complemented susceptibility conferred by the Arabidopsis ndr1-1 mutant to Pseudomonas syringae strains and also led to enhanced resistance to an oomycete pathogen Hyaloperonospora arabidopsidis. Such heightened resistance is associated with increased SA production and expression of the defense marker gene PATHOGENESIS RELATED 1 (PR1). In addition, we found that expression of PR1 and accumulation of SA were induced to modest levels in citrus infected with Candidatus Liberibacter asiaticus, the bacterial pathogen associated with HLB disease. Thus, our data suggest that CsNDR1 is a functional ortholog of Arabidopsis NDR1. Since Ca. L. asiaticus infection only activates modest levels of defense responses in citrus, we propose that genetically increasing SA/NDR1-mediated pathways could potentially lead to enhanced resistance against HLB, citrus canker, and other destructive diseases challenging global citrus production. PMID:23761797

Ambient temperature and genotype differentially affect developmental and phenotypic plasticity in Arabidopsis thaliana.

PubMed

Ibañez, Carla; Poeschl, Yvonne; Peterson, Tom; Bellstädt, Julia; Denk, Kathrin; Gogol-Döring, Andreas; Quint, Marcel; Delker, Carolin

2017-07-06

Global increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best. Here, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown under long day conditions in four different temperatures ranging from 16 to 28 °C. We used Q 10 , GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions. Genotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.

phenoSeeder - A Robot System for Automated Handling and Phenotyping of Individual Seeds.

PubMed

Jahnke, Siegfried; Roussel, Johanna; Hombach, Thomas; Kochs, Johannes; Fischbach, Andreas; Huber, Gregor; Scharr, Hanno

2016-11-01

The enormous diversity of seed traits is an intriguing feature and critical for the overwhelming success of higher plants. In particular, seed mass is generally regarded to be key for seedling development but is mostly approximated by using scanning methods delivering only two-dimensional data, often termed seed size. However, three-dimensional traits, such as the volume or mass of single seeds, are very rarely determined in routine measurements. Here, we introduce a device named phenoSeeder, which enables the handling and phenotyping of individual seeds of very different sizes. The system consists of a pick-and-place robot and a modular setup of sensors that can be versatilely extended. Basic biometric traits detected for individual seeds are two-dimensional data from projections, three-dimensional data from volumetric measures, and mass, from which seed density is also calculated. Each seed is tracked by an identifier and, after phenotyping, can be planted, sorted, or individually stored for further evaluation or processing (e.g. in routine seed-to-plant tracking pipelines). By investigating seeds of Arabidopsis (Arabidopsis thaliana), rapeseed (Brassica napus), and barley (Hordeum vulgare), we observed that, even for apparently round-shaped seeds of rapeseed, correlations between the projected area and the mass of seeds were much weaker than between volume and mass. This indicates that simple projections may not deliver good proxies for seed mass. Although throughput is limited, we expect that automated seed phenotyping on a single-seed basis can contribute valuable information for applications in a wide range of wild or crop species, including seed classification, seed sorting, and assessment of seed quality. © 2016 American Society of Plant Biologists. All Rights Reserved.

Arabidopsis CP12 mutants have reduced levels of phosphoribulokinase and impaired function of the Calvin–Benson cycle

PubMed Central

Elena López-Calcagno, Patricia; Omar Abuzaid, Amani; Lawson, Tracy

2017-01-01

Abstract CP12 is a small, redox-sensitive protein, the most detailed understanding of which is the thioredoxin-mediated regulation of the Calvin–Benson cycle, where it facilitates the formation of a complex between glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) in response to changes in light intensity. In most organisms, CP12 proteins are encoded by small multigene families, where the importance of each individual CP12 gene in vivo has not yet been reported. We used Arabidopsis thaliana T-DNA mutants and RNAi transgenic lines with reduced levels of CP12 transcript to determine the relative importance of each of the CP12 genes. We found that single cp12-1, cp12-2, and cp12-3 mutants do not develop a severe photosynthetic or growth phenotype. In contrast, reductions of both CP12-1 and CP12-2 transcripts lead to reductions in photosynthetic capacity and to slower growth and reduced seed yield. No clear phenotype for CP12-3 was evident. Additionally, the levels of PRK protein are reduced in the cp12-1, cp12-1/2, and multiple mutants. Our results suggest that there is functional redundancy between CP12-1 and CP12-2 in Arabidopsis where these proteins have a role in determining the level of PRK in mature leaves and hence photosynthetic capacity. PMID:28430985

Characterization of Xanthophyll Pigments, Photosynthetic Performance, Photon Energy Dissipation, Reactive Oxygen Species Generation and Carbon Isotope Discrimination during Artemisinin-Induced Stress in Arabidopsis thaliana

PubMed Central

Hussain, M. Iftikhar; Reigosa, Manuel J.

2015-01-01

Artemisinin, a potent antimalarial drug, is phytotoxic to many crops and weeds. The effects of artemisinin on stress markers, including fluorescence parameters, photosystem II photochemistry, photon energy dissipation, lipid peroxidation, reactive oxygen species generation and carbon isotope discrimination in Arabidopsis thaliana were studied. Arabidopsis ecotype Columbia (Col-0) seedlings were grown in perlite and watered with 50% Hoagland nutrient solution. Adult plants of Arabidopsis were treated with artemisinin at 0, 40, 80, 160 μM for one week. Artemisinin, in the range 40–160 μM, decreased the fresh biomass, chl a, b and leaf mineral contents. Photosynthetic efficiency, yield and electron transport rate in Arabidopsis were also reduced following exposure to 80 and 160 μM artemisinin. The ΦNPQ and NPQ were less than control. Artemisinin treatment caused an increase in root oxidizability and lipid peroxidation (MDA contents) of Arabidopsis. Calcium and nitrogen contents decreased after 80 and 160 μM artemisinin treatment compared to control. δ13C values were less negative following treatment with artemisinin as compared to the control. Artemisinin also decreased leaf protein contents in Arabidopsis. Taken together, these data suggest that artemisinin inhibits many physiological and biochemical processes in Arabidopsis. PMID:25635811

Revealing structure and assembly cues for Arabidopsis root-inhabiting bacterial microbiota.

PubMed

Bulgarelli, Davide; Rott, Matthias; Schlaeppi, Klaus; Ver Loren van Themaat, Emiel; Ahmadinejad, Nahal; Assenza, Federica; Rauf, Philipp; Huettel, Bruno; Reinhardt, Richard; Schmelzer, Elmon; Peplies, Joerg; Gloeckner, Frank Oliver; Amann, Rudolf; Eickhorst, Thilo; Schulze-Lefert, Paul

2012-08-02

The plant root defines the interface between a multicellular eukaryote and soil, one of the richest microbial ecosystems on Earth. Notably, soil bacteria are able to multiply inside roots as benign endophytes and modulate plant growth and development, with implications ranging from enhanced crop productivity to phytoremediation. Endophytic colonization represents an apparent paradox of plant innate immunity because plant cells can detect an array of microbe-associated molecular patterns (also known as MAMPs) to initiate immune responses to terminate microbial multiplication. Several studies attempted to describe the structure of bacterial root endophytes; however, different sampling protocols and low-resolution profiling methods make it difficult to infer general principles. Here we describe methodology to characterize and compare soil- and root-inhabiting bacterial communities, which reveals not only a function for metabolically active plant cells but also for inert cell-wall features in the selection of soil bacteria for host colonization. We show that the roots of Arabidopsis thaliana, grown in different natural soils under controlled environmental conditions, are preferentially colonized by Proteobacteria, Bacteroidetes and Actinobacteria, and each bacterial phylum is represented by a dominating class or family. Soil type defines the composition of root-inhabiting bacterial communities and host genotype determines their ribotype profiles to a limited extent. The identification of soil-type-specific members within the root-inhabiting assemblies supports our conclusion that these represent soil-derived root endophytes. Surprisingly, plant cell-wall features of other tested plant species seem to provide a sufficient cue for the assembly of approximately 40% of the Arabidopsis bacterial root-inhabiting microbiota, with a bias for Betaproteobacteria. Thus, this root sub-community may not be Arabidopsis-specific but saprophytic bacteria that would naturally be found

Challenging the Metallothionein (MT) Gene of Biomphalaria glabrata: Unexpected Response Patterns Due to Cadmium Exposure and Temperature Stress.

PubMed

Niederwanger, Michael; Dvorak, Martin; Schnegg, Raimund; Pedrini-Martha, Veronika; Bacher, Katharina; Bidoli, Massimo; Dallinger, Reinhard

2017-08-11

Metallothioneins (MTs) are low-molecular-mass, cysteine-rich, metal binding proteins. In most animal species, they are involved in metal homeostasis and detoxification, and provide protection from oxidative stress. Gastropod MTs are highly diversified, exhibiting unique features and adaptations like metal specificity and multiplications of their metal binding domains. Here, we show that the MT gene of Biomphalaria glabrata , one of the largest MT genes identified so far, is composed in a unique way. The encoding for an MT protein has a three-domain structure and a C-terminal, Cys-rich extension. Using a bioinformatic approach involving structural and in silico analysis of putative transcription factor binding sites (TFBs), we found that this MT gene consists of five exons and four introns. It exhibits a regulatory promoter region containing three metal-responsive elements (MREs) and several TFBs with putative involvement in environmental stress response, and regulation of gene expression. Quantitative real-time polymerase chain reaction (qRT-PCR) data indicate that the MT gene is not inducible by cadmium (Cd) nor by temperature challenges (heat and cold), despite significant Cd uptake within the midgut gland and the high Cd tolerance of metal-exposed snails.

Challenging the Metallothionein (MT) Gene of Biomphalaria glabrata: Unexpected Response Patterns Due to Cadmium Exposure and Temperature Stress

PubMed Central

Dvorak, Martin; Schnegg, Raimund; Pedrini-Martha, Veronika; Bacher, Katharina; Bidoli, Massimo; Dallinger, Reinhard

2017-01-01

Metallothioneins (MTs) are low-molecular-mass, cysteine-rich, metal binding proteins. In most animal species, they are involved in metal homeostasis and detoxification, and provide protection from oxidative stress. Gastropod MTs are highly diversified, exhibiting unique features and adaptations like metal specificity and multiplications of their metal binding domains. Here, we show that the MT gene of Biomphalaria glabrata, one of the largest MT genes identified so far, is composed in a unique way. The encoding for an MT protein has a three-domain structure and a C-terminal, Cys-rich extension. Using a bioinformatic approach involving structural and in silico analysis of putative transcription factor binding sites (TFBs), we found that this MT gene consists of five exons and four introns. It exhibits a regulatory promoter region containing three metal-responsive elements (MREs) and several TFBs with putative involvement in environmental stress response, and regulation of gene expression. Quantitative real-time polymerase chain reaction (qRT-PCR) data indicate that the MT gene is not inducible by cadmium (Cd) nor by temperature challenges (heat and cold), despite significant Cd uptake within the midgut gland and the high Cd tolerance of metal-exposed snails. PMID:28800079

Deletion within the metallothionein locus of cadmium-tolerant Synechococcus PCC 6301 involving a highly iterated palindrome (HIP1).

PubMed

Gupta, A; Morby, A P; Turner, J S; Whitton, B A; Robinson, N J

1993-01-01

Genomic rearrangements involving amplification of metallothionein (MT) genes have been reported in metal-tolerant eukaryotes. Similarly, we have recently observed amplification and rearrangement of a prokaryotic MT locus, smt, in cells of Synechococcus PCC 6301 selected for Cd tolerance. Following the characterization of this locus, the altered smt region has now been isolated from a Cd-tolerant cell line, C3.2, and its nucleotide sequence determined. This has identified a deletion within smtB, which encodes a trans-acting repressor of smt transcription. Two identical palindromic octanucleotides (5'-GCGATC-GC-3') traverse both borders of the excised element. This palindromic sequence is highly represented in the smt locus (7 occurrences in 1326 nucleotides) and analysis of the GenBank/EMBL/DDBJ DNA Nucleotide Sequence Data Libraries reveals that this is a highly iterated palindrome (HIP1) in other known sequences from Synechococcus strains (estimated to occur at an average frequency of once every c. 664 bp). HIP1 is also abundant in the genomes of other cyanobacteria. The functional significance of smtB deletion and the possible role of HIP1 in genome plasticity and adaptation in cyanobacteria are discussed.

Elevated nitrogen metabolism and nitric oxide production are involved in Arabidopsis resistance to acid rain.

PubMed

Qiao, Fang; Zhang, Xi-Min; Liu, Xiang; Chen, Juan; Hu, Wen-Jun; Liu, Ting-Wu; Liu, Ji-Yun; Zhu, Chun-Quan; Ghoto, Kabir; Zhu, Xue-Yi; Zheng, Hai-Lei

2018-06-01

Acid rain (AR) can induce great damages to plants and could be classified into different types according to the different SO 4 2- /NO 3 - ratio. However, the mechanism of plants' responding to different types of AR has not been elucidated clearly. Here, we found that nitric-rich simulated AR (N-SiAR) induced less leaves injury as lower necrosis percentage, better physiological parameters and reduced oxidative damage in the leaves of N-SiAR treated Arabidopsis thaliana compared with sulfate and nitrate mixed (SN-SiAR) or sulfuric-rich (S-SiAR) simulated AR treated ones. Of these three types of SiAR, N-SiAR treated Arabidopsis maintained the highest of nitrogen (N) content, nitrate reductase (NR) and nitrite reductase (NiR) activity as well as N metabolism related genes expression level. Nitric oxide (NO) content showed that N-SiAR treated seedlings had a higher NO level compared to SN-SiAR or S-SiAR treated ones. A series of NO production and elimination related reagents and three NO production-related mutants were used to further confirm the role of NO in regulating acid rain resistance in N-SiAR treated Arabidopsis seedlings. Taken together, we concluded that an elevated N metabolism and enhanced NO production are involved in the tolerance to different types of AR in Arabidopsis. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

NADP-Malate Dehydrogenase of Sweet Sorghum Improves Salt Tolerance of Arabidopsis thaliana.

PubMed

Guo, Yuanyuan; Song, Yushuang; Zheng, Hongxiang; Zhang, Yi; Guo, Jianrong; Sui, Na

2018-06-08

Sweet sorghum is a C 4 crop that shows high salt tolerance and high yield. NADP-malate dehydrogenase ( NADP-ME) is a crucial enzyme of the C 4 pathway. The regulatory mechanism of NADP-ME remains unclear. In this study, we isolated SbNADP-ME from sweet sorghum. The open reading frame of SbNADP-ME is 1911 bp and 637 amino acid residues. Quantitative real-time PCR analysis showed that SbNADP-ME transcription in sweet sorghum was enhanced by salt stress. The SbNADP-ME transcript level was highest under exposure to 150 mM NaCl. Arabidopsis overexpressing SbNADP-ME showed increased germination rate and root length under NaCl treatments. At the seedling stage, physiological photosynthesis parameters, chlorophyll content, PSII photochemical efficiency, and PSI oxidoreductive activity in the wild type decreased more severely than in the overexpression lines but less than in T-DNA insertion mutants under salt stress. Overexpression of SbNADP-ME in Arabidopsis may also increase osmotic adjustment and scavenging activity on DPPH and decrease membrane peroxidation. These results suggest that SbNADP-ME overexpression in Arabidopsis increases salt tolerance and alleviates PSII and PSI photoinhibition under salt stress by improving photosynthetic capacity.

Mutational effects of γ-rays and carbon ion beams on Arabidopsis seedlings

PubMed Central

Yoshihara, Ryouhei; Nozawa, Shigeki; Hase, Yoshihiro; Narumi, Issay; Hidema, Jun; Sakamoto, Ayako N.

2013-01-01

To assess the mutational effects of radiation on vigorously proliferating plant tissue, the mutation spectrum was analyzed with Arabidopsis seedlings using the plasmid-rescue method. Transgenic plants containing the Escherichia coli rpsL gene were irradiated with γ-rays and carbon ion beams (320-MeV 12C6+), and mutations in the rpsL gene were analyzed. Mutant frequency increased significantly following irradiation by γ-rays, but not by 320-MeV 12C6+. Mutation spectra showed that both radiations increased the frequency of frameshifts and other mutations, including deletions and insertions, but only γ-rays increased the frequency of total base substitutions. These results suggest that the type of DNA lesions which cause base substitutions were less often induced by 320-MeV 12C6+ than by γ-rays in Arabidopsis seedlings. Furthermore, γ-rays never increased the frequencies of G:C to T:A or A:T to C:G transversions, which are caused by oxidized guanine; 320-MeV 12C6+, however, produced a slight increase in both transversions. Instead, γ-rays produced a significant increase in the frequency of G:C to A:T transitions. These results suggest that 8-oxoguanine has little effect on mutagenesis in Arabidopsis cells. PMID:23728320

Intracellular localization of Arabidopsis sulfurtransferases.

PubMed

Bauer, Michael; Dietrich, Christof; Nowak, Katharina; Sierralta, Walter D; Papenbrock, Jutta

2004-06-01

Sulfurtransferases (Str) comprise a group of enzymes widely distributed in archaea, eubacteria, and eukaryota which catalyze the transfer of a sulfur atom from suitable sulfur donors to nucleophilic sulfur acceptors. In all organisms analyzed to date, small gene families encoding Str proteins have been identified. The gene products were localized to different compartments of the cells. Our interest concerns the localization of Str proteins encoded in the nuclear genome of Arabidopsis. Computer-based prediction methods revealed localization in different compartments of the cell for six putative AtStrs. Several methods were used to determine the localization of the AtStr proteins experimentally. For AtStr1, a mitochondrial localization was demonstrated by immunodetection in the proteome of isolated mitochondria resolved by one- and two-dimensional gel electrophoresis and subsequent blotting. The respective mature AtStr1 protein was identified by mass spectrometry sequencing. The same result was obtained by transient expression of fusion constructs with the green fluorescent protein in Arabidopsis protoplasts, whereas AtStr2 was exclusively localized to the cytoplasm by this method. Three members of the single-domain AtStr were localized in the chloroplasts as demonstrated by transient expression of green fluorescent protein fusions in protoplasts and stomata, whereas the single-domain AtStr18 was shown to be cytoplasmic. The remarkable subcellular distribution of AtStr15 was additionally analyzed by transmission electron immunomicroscopy using a monospecific antibody against green fluorescent protein, indicating an attachment to the thylakoid membrane. The knowledge of the intracellular localization of the members of this multiprotein family will help elucidate their specific functions in the organism.

Reducing Isozyme Competition Increases Target Fatty Acid Accumulation in Seed Triacylglycerols of Transgenic Arabidopsis1[OPEN

PubMed Central

van Erp, Harrie; Shockey, Jay; Zhang, Meng; Adhikari, Neil D.; Browse, John

2015-01-01

One goal of green chemistry is the production of industrially useful fatty acids (FAs) in crop plants. We focus on hydroxy fatty acids (HFAs) and conjugated polyenoic FAs (α-eleostearic acids [ESAs]) using Arabidopsis (Arabidopsis thaliana) as a model. These FAs are found naturally in seed oils of castor (Ricinus communis) and tung tree (Vernicia fordii), respectively, and used for the production of lubricants, nylon, and paints. Transgenic oils typically contain less target FA than that produced in the source species. We hypothesized that competition between endogenous and transgenic isozymes for substrates limits accumulation of unique FAs in Arabidopsis seeds. This hypothesis was tested by introducing a mutation in Arabidopsis diacylglycerol acyltransferase1 (AtDGAT1) in a line expressing castor FA hydroxylase and acyl-Coenzyme A:RcDGAT2 in its seeds. This led to a 17% increase in the proportion of HFA in seed oil. Expression of castor phospholipid:diacylglycerol acyltransferase 1A in this line increased the proportion of HFA by an additional 12%. To determine if our observations are more widely applicable, we investigated if isozyme competition influenced production of ESA. Expression of tung tree FA conjugase/desaturase in Arabidopsis produced approximately 7.5% ESA in seed lipids. Coexpression of VfDGAT2 increased ESA levels to approximately 11%. Overexpression of VfDGAT2 combined with suppression of AtDGAT1 increased ESA accumulation to 14% to 15%. Our results indicate that isozyme competition is a limiting factor in the engineering of unusual FAs in heterologous plant systems and that reduction of competition through mutation and RNA suppression may be a useful component of seed metabolic engineering strategies. PMID:25739701

Potential role of alpha-synuclein and metallothionein in lead-induced inclusion body formation.

PubMed

Zuo, Peijun; Qu, Wei; Cooper, Ryan N; Goyer, Robert A; Diwan, Bhalchandra A; Waalkes, Michael P

2009-09-01

Lead (Pb) produces aggresome-like inclusion bodies (IBs) in target cells as a toxic response. Our prior work shows metallothionein (MT) is required for this process. We used MT-I/II double knockout (MT-null) and parental wild-type (WT) cell lines to further explore the formation process of Pb-induced IBs. Unlike WT cells, MT-null cells did not form IBs after Pb exposure. Western blot of cytosol showed soluble MT protein in WT cells was lost during Pb exposure as IBs formed. Transfection of MT-I into MT-null cells allowed IBs formation after Pb exposure. Considering Pb-induced IBs may be like disease-related aggresomes, which often contain alpha-synuclein (Scna), we investigated Scna expression in cells capable (WT) and incapable (MT-null) of producing IBs after Pb exposure. Scna protein showed poor basal expression in MT-null cells. Pb exposure increased Scna expression only in WT cells. MT transfection increased Scna transcript to WT levels. In WT or MT-transfected MT-null cells, Pb-induced Scna expression rapidly increased and then decreased over 48 h as Pb-induced IBs were formed. A direct interaction between Scna and MT was confirmed ex vivo by antibody pulldown assay where the proteins coprecipitated with an antibody to MT. Pb exposure caused increased colocalization of MT and Scna proteins with time only in WT cells. In WT mice after chronic Pb exposure Scna was localized in renal cells containing forming IBs, whereas MT-null mice did not form IBs. Thus, Scna could be component of Pb-induced IBs and, with MT, may play a role in IBs formation.

Genome-Wide Identification of Arabidopsis Coiled-Coil Proteins and Establishment of the ARABI-COIL Database1

PubMed Central

Rose, Annkatrin; Manikantan, Sankaraganesh; Schraegle, Shannon J.; Maloy, Michael A.; Stahlberg, Eric A.; Meier, Iris

2004-01-01

Increasing evidence demonstrates the importance of long coiled-coil proteins for the spatial organization of cellular processes. Although several protein classes with long coiled-coil domains have been studied in animals and yeast, our knowledge about plant long coiled-coil proteins is very limited. The repeat nature of the coiled-coil sequence motif often prevents the simple identification of homologs of animal coiled-coil proteins by generic sequence similarity searches. As a consequence, counterparts of many animal proteins with long coiled-coil domains, like lamins, golgins, or microtubule organization center components, have not been identified yet in plants. Here, all Arabidopsis proteins predicted to contain long stretches of coiled-coil domains were identified by applying the algorithm MultiCoil to a genome-wide screen. A searchable protein database, ARABI-COIL (http://www.coiled-coil.org/arabidopsis), was established that integrates information on number, size, and position of predicted coiled-coil domains with subcellular localization signals, transmembrane domains, and available functional annotations. ARABI-COIL serves as a tool to sort and browse Arabidopsis long coiled-coil proteins to facilitate the identification and selection of candidate proteins of potential interest for specific research areas. Using the database, candidate proteins were identified for Arabidopsis membrane-bound, nuclear, and organellar long coiled-coil proteins. PMID:15020757

The cell wall of the Arabidopsis pollen tube--spatial distribution, recycling, and network formation of polysaccharides.

PubMed

Chebli, Youssef; Kaneda, Minako; Zerzour, Rabah; Geitmann, Anja

2012-12-01

The pollen tube is a cellular protuberance formed by the pollen grain, or male gametophyte, in flowering plants. Its principal metabolic activity is the synthesis and assembly of cell wall material, which must be precisely coordinated to sustain the characteristic rapid growth rate and to ensure geometrically correct and efficient cellular morphogenesis. Unlike other model species, the cell wall of the Arabidopsis (Arabidopsis thaliana) pollen tube has not been described in detail. We used immunohistochemistry and quantitative image analysis to provide a detailed profile of the spatial distribution of the major cell wall polymers composing the Arabidopsis pollen tube cell wall. Comparison with predictions made by a mechanical model for pollen tube growth revealed the importance of pectin deesterification in determining the cell diameter. Scanning electron microscopy demonstrated that cellulose microfibrils are oriented in near longitudinal orientation in the Arabidopsis pollen tube cell wall, consistent with a linear arrangement of cellulose synthase CESA6 in the plasma membrane. The cellulose label was also found inside cytoplasmic vesicles and might originate from an early activation of cellulose synthases prior to their insertion into the plasma membrane or from recycling of short cellulose polymers by endocytosis. A series of strategic enzymatic treatments also suggests that pectins, cellulose, and callose are highly cross linked to each other.