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Sample records for plants arabidopsis tobacco

  1. Uncoupling Auxin and Ethylene Effects in Transgenic Tobacco and Arabidopsis Plants.

    PubMed Central

    Romano, CP; Cooper, ML; Klee, HJ

    1993-01-01

    Overproduction of auxin in transgenic plants also results in the overproduction of ethylene. Plants overproducing both auxin and ethylene display inhibition of stem elongation and growth, increased apical dominance, and leaf epinasty. To determine the relative roles of auxin and ethylene in these processes, transgenic tobacco and Arabidopsis plants expressing the auxin-overproducing tryptophan monooxygenase transgene were crossed to plants expressing an ethylene synthesis-inhibiting 1-aminocyclopropane-1-carboxylate deaminase transgene. Tobacco and Arabidopsis plants with elevated auxin and normal levels of ethylene were obtained by this strategy. Transgenic auxin-overproducing Arabidopsis plants were also crossed with the ethylene-insensitive ein1 and ein2 mutants. Analysis of these plants indicates that apical dominance and leaf epinasty are primarily controlled by auxin rather than ethylene. However, ethylene is partially responsible for the inhibition of stem elongation observed in auxin-overproducing tobacco. Finally, these data show that auxin overproduction can be effectively uncoupled from ethylene overproduction in transgenic plants to enable direct manipulation of plant morphology for agronomic and horticultural purposes. PMID:12271061

  2. Suppressed expression of the apoplastic ascorbate oxidase gene increases salt tolerance in tobacco and Arabidopsis plants.

    PubMed

    Yamamoto, Atsuko; Bhuiyan, Md Nazmul H; Waditee, Rungaroon; Tanaka, Yoshito; Esaka, Muneharu; Oba, Kazuko; Jagendorf, André T; Takabe, Teruhiro

    2005-07-01

    Transgenic tobacco plants expressing the ascorbate oxidase (AAO) gene in sense and antisense orientations, and an Arabidopsis mutant in which the T-DNA was inserted into a putative AAO gene, were used to examine the potential roles of AAO for salt-stress tolerance in plants. AAO activities in the transgenic tobacco plants expressing the gene in sense and antisense orientations were, respectively, about 16-fold and 0.2-fold of those in the wild type. Under normal growth conditions, no significant differences in phenotypes were observed, except for a delay in flowering time in the antisense plants. However, at high salinity, the percentage germination, photosynthetic activity, and seed yields were higher in antisense plants, with progressively lower levels in the wild type and the sense plants. The redox state of apoplastic ascorbate in sense plants was very low even under normal growth conditions. Upon salt stress, the redox state of symplastic and apoplastic ascorbate decreased among the three types of plants, but was lowest in the sense plants. The hydrogen peroxide contents in the symplastic and apoplastic spaces were higher in sense plants, progressively lower in the wild type, followed by the antisense plants. The Arabidopsis T-DNA inserted mutant exhibited very low ascorbate oxidase activity, and its phenotype was similar to that of antisense tobacco plants. These results suggest that the suppressed expression of apoplastic AAO under salt-stress conditions leads to a relatively low level of hydrogen peroxide accumulation and a high redox state of symplastic and apoplastic ascorbate which, in turn, permits a higher seed yield.

  3. UV-C-irradiated Arabidopsis and tobacco emit volatiles that trigger genomic instability in neighboring plants.

    PubMed

    Yao, Youli; Danna, Cristian H; Zemp, Franz J; Titov, Viktor; Ciftci, Ozan Nazim; Przybylski, Roman; Ausubel, Frederick M; Kovalchuk, Igor

    2011-10-01

    We have previously shown that local exposure of plants to stress results in a systemic increase in genome instability. Here, we show that UV-C-irradiated plants produce a volatile signal that triggers an increase in genome instability in neighboring nonirradiated Arabidopsis thaliana plants. This volatile signal is interspecific, as UV-C-irradiated Arabidopsis plants transmit genome destabilization to naive tobacco (Nicotiana tabacum) plants and vice versa. We report that plants exposed to the volatile hormones methyl salicylate (MeSA) or methyl jasmonate (MeJA) exhibit a similar level of genome destabilization as UV-C-irradiated plants. We also found that irradiated Arabidopsis plants produce MeSA and MeJA. The analysis of mutants impaired in the synthesis and/or response to salicylic acid (SA) and/or jasmonic acid showed that at least one other volatile compound besides MeSA and MeJA can communicate interplant genome instability. The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (npr1) mutant, defective in SA signaling, is impaired in both the production and the perception of the volatile signals, demonstrating a key role for NPR1 as a central regulator of genome stability. Finally, various forms of stress resulting in the formation of necrotic lesions also generate a volatile signal that leads to genomic instability.

  4. Over-expression of Arabidopsis CAP causes decreased cell expansion leading to organ size reduction in transgenic tobacco plants.

    PubMed

    Barrero, Roberto A; Umeda, Masaaki; Yamamura, Saburo; Uchimiya, Hirofumi

    2003-04-01

    Cyclase-associated proteins (CAP) are multifunctional proteins involved in Ras-cAMP signalling and regulation of the actin cytoskeleton. It has recently been demonstrated that over-expression of AtCAP1 in transgenic arabidopsis plants causes severe morphological defects owing to loss of actin filaments. To test the generality of the function of AtCAP1 in plants, transgenic tobacco plants over-expressing an arabidopsis CAP (AtCAP1) under the regulation of a glucocorticoid-inducible promoter were produced. Over-expression of AtCAP1 in transgenic tobacco plants led to growth abnormalities, in particular a reduction in the size of leaves. Morphological alterations in leaves were the result of reduced elongation of epidermal and mesophyll cells.

  5. Inhibition of cell proliferation, cell expansion and differentiation by the Arabidopsis SUPERMAN gene in transgenic tobacco plants.

    PubMed

    Bereterbide, A; Hernould, M; Castera, S; Mouras, A

    2001-11-01

    Plant development depends upon the control of growth, organization and differentiation of cells derived from shoot and root meristems. Among the genes involved in flower organ determination, the cadastral gene SUPERMAN controls the boundary between whorls 3 and 4 and the growth of the adaxial outer ovule integument by down-regulating cell divisions. To determine the precise function of this gene we overexpressed ectopically the Arabidopsis thaliana (L.) Heynh. SUPERMAN gene in tobacco (Nicotiana tabacum L.). The transgenic plants exhibited a dwarf phenotype. Histologically and cytologically detailed analyses showed that dwarfism is correlated with a reduction in cell number, which is in agreement with the SUPERMAN function in Arabidopsis. Furthermore, a reduction in cell expansion and an impairment of cell differentiation were observed in tobacco organs. These traits were observed in differentiated vegetative and floral organs but not in meristem structures. A potential effect of the SUPERMAN transcription factor in the control of gibberellin biosynthesis is discussed.

  6. UV-C–Irradiated Arabidopsis and Tobacco Emit Volatiles That Trigger Genomic Instability in Neighboring Plants[W

    PubMed Central

    Yao, Youli; Danna, Cristian H.; Zemp, Franz J.; Titov, Viktor; Ciftci, Ozan Nazim; Przybylski, Roman; Ausubel, Frederick M.; Kovalchuk, Igor

    2011-01-01

    We have previously shown that local exposure of plants to stress results in a systemic increase in genome instability. Here, we show that UV-C–irradiated plants produce a volatile signal that triggers an increase in genome instability in neighboring nonirradiated Arabidopsis thaliana plants. This volatile signal is interspecific, as UV-C–irradiated Arabidopsis plants transmit genome destabilization to naive tobacco (Nicotiana tabacum) plants and vice versa. We report that plants exposed to the volatile hormones methyl salicylate (MeSA) or methyl jasmonate (MeJA) exhibit a similar level of genome destabilization as UV-C–irradiated plants. We also found that irradiated Arabidopsis plants produce MeSA and MeJA. The analysis of mutants impaired in the synthesis and/or response to salicylic acid (SA) and/or jasmonic acid showed that at least one other volatile compound besides MeSA and MeJA can communicate interplant genome instability. The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (npr1) mutant, defective in SA signaling, is impaired in both the production and the perception of the volatile signals, demonstrating a key role for NPR1 as a central regulator of genome stability. Finally, various forms of stress resulting in the formation of necrotic lesions also generate a volatile signal that leads to genomic instability. PMID:22028460

  7. Overexpression of a peroxidase gene (AtPrx64) of Arabidopsis thaliana in tobacco improves plant's tolerance to aluminum stress.

    PubMed

    Wu, Yuanshuang; Yang, Zhili; How, Jingyi; Xu, Huini; Chen, Limei; Li, Kunzhi

    2017-08-16

    AtPrx64 is one of the peroxidases gene up-regulated in Al stress and has some functions in the formation of plant second cell wall. Its overexpression may improve plant tolerance to Al by some ways. Studies on its function under Al stress may help us to understand the mechanism of plant tolerance to Al stress. In Arabidopsis thaliana, the expressions of some genes (AtPrxs) encoding class III plant peroxidases have been found to be either up-regulated or down-regulated under aluminum (Al) stress. Among 73 genes that encode AtPrxs in Arabidopsis, AtPrx64 is always up-regulated by Al stress, suggesting this gene plays protective roles in response to such stress. In this study, transgenic tobacco plants were generated to examine the effects of overexpressing of AtPrx64 gene on the tolerance to Al stress. The results showed that overexpression of AtPrx64 gene increased the root growth and reduced the accumulation of Al and ROS in the roots. Compared with wild type controls, transgenic tobaccos had much less soluble proteins and malondialdehyde in roots and much more root citrate exudation. The activity of plasma membrane (PM) H(+)-ATPase, the phosphorylation of PM H(+)-ATPase and its interaction with 14-3-3 proteins increased in transgenic tobaccos; moreover, the content of lignin in root tips also increased. Taken together, these results showed that overexpression of AtPrx64 gene might enhance the tolerance of tobacco to Al stress.

  8. Apple latent spherical virus vectors for reliable and effective virus-induced gene silencing among a broad range of plants including tobacco, tomato, Arabidopsis thaliana, cucurbits, and legumes

    SciTech Connect

    Igarashi, Aki; Yamagata, Kousuke; Sugai, Tomokazu; Takahashi, Yukari; Sugawara, Emiko; Tamura, Akihiro; Yaegashi, Hajime; Yamagishi, Noriko; Takahashi, Tsubasa; Isogai, Masamichi; Takahashi, Hideki; Yoshikawa, Nobuyuki

    2009-04-10

    Apple latent spherical virus (ALSV) vectors were evaluated for virus-induced gene silencing (VIGS) of endogenous genes among a broad range of plant species. ALSV vectors carrying partial sequences of a subunit of magnesium chelatase (SU) and phytoene desaturase (PDS) genes induced highly uniform knockout phenotypes typical of SU and PDS inhibition on model plants such as tobacco and Arabidopsis thaliana, and economically important crops such as tomato, legume, and cucurbit species. The silencing phenotypes persisted throughout plant growth in these plants. In addition, ALSV vectors could be successfully used to silence a meristem gene, proliferating cell nuclear antigen and disease resistant N gene in tobacco and RCY1 gene in A. thaliana. As ALSV infects most host plants symptomlessly and effectively induces stable VIGS for long periods, the ALSV vector is a valuable tool to determine the functions of interested genes among a broad range of plant species.

  9. Assays of PCB congeners and organochlorine insecticides with the transgenic Arabidopsis and tobacco plants carrying recombinant guinea pig AhR and GUS reporter genes.

    PubMed

    Gion, Keiko; Inui, Hideyuki; Sasaki, Hideaki; Utani, Yasushi; Kodama, Susumu; Ohkawa, Hideo

    2012-01-01

    Certain congeners of polychlorinated biphenyls (PCBs) and organochlorine insecticides are ligands of aryl hydrocarbon receptors (AhRs) in animals. A recombinant guinea pig (g) AhR, XgDV, was constructed by fusing the ligand-binding domain of gAhR, the DNA-binding domain of LexA, and the transactivating domain of VP16. Then, the expression unit of β-glucuronidase (GUS) reporter gene regulated by XgDV was introduced into Arabidopsis and tobacco plants. When the transgenic Arabidopsis XgDV plants were cultured on Murashige-Skoog (MS) medium containing PCB congeners, the GUS activity in the plants increased toxic equivalent (TEQ)-dependently. The GUS activity in the transgenic Arabidopsis XgDV plants cultured on MS medium containing the organochlorine insecticide dieldrin was also induced. On the other hand, in the case of DDT, the GUS activity induced by 3-methylcholanthere in the plants decreased. The transgenic Arabidopsis XgDV plants detected 1000 ng g(-1) PCB126 in 1 g of soils. Thus the XgDV plants seemed to be useful for convenient assays of PCB congeners and organochlorine insecticides, without any extraction and purification steps.

  10. An Intergenic Region Shared by At4g35985 and At4g35987 in Arabidopsis thaliana Is a Tissue Specific and Stress Inducible Bidirectional Promoter Analyzed in Transgenic Arabidopsis and Tobacco Plants

    PubMed Central

    Banerjee, Joydeep; Sahoo, Dipak Kumar; Dey, Nrisingha; Houtz, Robert L.; Maiti, Indu Bhushan

    2013-01-01

    On chromosome 4 in the Arabidopsis genome, two neighboring genes (calmodulin methyl transferase At4g35987 and senescence associated gene At4g35985) are located in a head-to-head divergent orientation sharing a putative bidirectional promoter. This 1258 bp intergenic region contains a number of environmental stress responsive and tissue specific cis-regulatory elements. Transcript analysis of At4g35985 and At4g35987 genes by quantitative real time PCR showed tissue specific and stress inducible expression profiles. We tested the bidirectional promoter-function of the intergenic region shared by the divergent genes At4g35985 and At4g35987 using two reporter genes (GFP and GUS) in both orientations in transient tobacco protoplast and Agro-infiltration assays, as well as in stably transformed transgenic Arabidopsis and tobacco plants. In transient assays with GFP and GUS reporter genes the At4g35985 promoter (P85) showed stronger expression (about 3.5 fold) compared to the At4g35987 promoter (P87). The tissue specific as well as stress responsive functional nature of the bidirectional promoter was evaluated in independent transgenic Arabidopsis and tobacco lines. Expression of P85 activity was detected in the midrib of leaves, leaf trichomes, apical meristemic regions, throughout the root, lateral roots and flowers. The expression of P87 was observed in leaf-tip, hydathodes, apical meristem, root tips, emerging lateral root tips, root stele region and in floral tissues. The bidirectional promoter in both orientations shows differential up-regulation (2.5 to 3 fold) under salt stress. Use of such regulatory elements of bidirectional promoters showing spatial and stress inducible promoter-functions in heterologous system might be an important tool for plant biotechnology and gene stacking applications. PMID:24260266

  11. 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

  12. Transgenic tobacco and Arabidopsis plants expressing the two multifunctional sorghum cytochrome P450 enzymes, CYP79A1 and CYP71E1, are cyanogenic and accumulate metabolites derived from intermediates in Dhurrin biosynthesis.

    PubMed

    Bak, S; Olsen, C E; Halkier, B A; Møller, B L

    2000-08-01

    Novel cyanogenic plants have been generated by the simultaneous expression of the two multifunctional sorghum (Sorghum bicolor [L.] Moench) cytochrome P450 enzymes CYP79A1 and CYP71E1 in tobacco (Nicotiana tabacum cv Xanthi) and Arabidopsis under the regulation of the constitutive 35S promoter. CYP79A1 and CYP71E1 catalyze the conversion of the parent amino acid tyrosine to p-hydroxymandelonitrile, the aglycone of the cyanogenic glucoside dhurrin. CYP79A1 catalyzes the conversion of tyrosine to p-hydroxyphenylacetaldoxime and CYP71E1, the subsequent conversion to p-hydroxymandelonitrile. p-Hydroxymandelonitrile is labile and dissociates into p-hydroxybenzaldehyde and hydrogen cyanide, the same products released from dhurrin upon cell disruption as a result of pest or herbivore attack. In transgenic plants expressing CYP79A1 as well as CYP71E1, the activity of CYP79A1 is higher than that of CYP71E1, resulting in the accumulation of several p-hydroxyphenylacetaldoxime-derived products in the addition to those derived from p-hydroxymandelonitrile. Transgenic tobacco and Arabidopsis plants expressing only CYP79A1 accumulate the same p-hydroxyphenylacetaldoxime-derived products as transgenic plants expressing both sorghum cytochrome P450 enzymes. In addition, the transgenic CYP79A1 Arabidopsis plants accumulate large amounts of p-hydroxybenzylglucosinolate. In transgenic Arabidopsis expressing CYP71E1, this enzyme and the enzymes of the pre-existing glucosinolate pathway compete for the p-hydroxyphenylacetaldoxime as substrate, resulting in the formation of small amounts of p-hydroxybenzylglucosinolate. Cyanogenic glucosides are phytoanticipins, and the present study demonstrates the feasibility of expressing cyanogenic compounds in new plant species by gene transfer technology to improve pest and disease resistance.

  13. Nitrate metabolism in tobacco leaves overexpressing Arabidopsis nitrite reductase.

    PubMed

    Davenport, Susie; Le Lay, Pascaline; Sanchez-Tamburrrino, Juan Pablo

    2015-12-01

    Primary nitrogen assimilation in plants includes the reduction of nitrite to ammonium in the chloroplasts by the enzyme nitrite reductase (NiR EC:1.7.7.1) or in the plastids of non-photosynthetic organs. Here we report on a study overexpressing the Arabidopsis thaliana NiR (AtNiR) gene in tobacco plants under the control of a constitutive promoter (CERV - Carnation Etched Ring Virus). The aim was to overexpress AtNiR in an attempt to alter the level of residual nitrite in the leaf which can act as precursor to the formation of nitrosamines. The impact of increasing the activity of AtNiR produced an increase in leaf protein and a stay-green phenotype in the primary transformed AtNiR population. Investigation of the T1 homozygous population demonstrated elevated nitrate reductase (NR) activity, reductions in leaf nitrite and nitrate and the amino acids proline, glutamine and glutamate. Chlorophyl content of the transgenic lines was increased, as evidenced by the stay-green phenotype. This reveals the importance of NiR in primary nitrogen assimilation and how modification of this key enzyme affects both the nitrogen and carbon metabolism of tobacco plants.

  14. Identification of natural diterpenes that inhibit bacterial wilt disease in tobacco, tomato and Arabidopsis.

    PubMed

    Seo, Shigemi; Gomi, Kenji; Kaku, Hisatoshi; Abe, Hiroshi; Seto, Hideharu; Nakatsu, Shingo; Neya, Masahiro; Kobayashi, Michie; Nakaho, Kazuhiro; Ichinose, Yuki; Mitsuhara, Ichiro; Ohashi, Yuko

    2012-08-01

    The soil-borne bacterial pathogen Ralstonia solanacearum invades a broad range of plants through their roots, resulting in wilting of the plant, but no effective protection against this disease has been developed. Two bacterial wilt disease-inhibiting compounds were biochemically isolated from tobacco and identified as sclareol and cis-abienol, labdane-type diterpenes. When exogenously applied to their roots, sclareol and cis-abienol inhibited wilt disease in tobacco, tomato and Arabidopsis plants without exhibiting any antibacterial activity. Microarray analysis identified many sclareol-responsive genes in Arabidopsis roots, including genes encoding or with a role in ATP-binding cassette (ABC) transporters, and biosynthesis and signaling of defense-related molecules and mitogen-activated protein kinase (MAPK) cascade components. Inhibition of wilt disease by sclareol was attenuated in Arabidopsis mutants defective in the ABC transporter AtPDR12, the MAPK MPK3, and ethylene and abscisic acid signaling pathways, and also in transgenic tobacco plants with reduced expression of NtPDR1, a tobacco homolog of AtPDR12. These results suggest that multiple host factors are involved in the inhibition of bacterial wilt disease by sclareol-related compounds.

  15. Transformation of beta-lycopene cyclase genes from Salicornia europaea and Arabidopsis conferred salt tolerance in Arabidopsis and tobacco.

    PubMed

    Chen, Xianyang; Han, Heping; Jiang, Ping; Nie, Lingling; Bao, Hexigeduleng; Fan, Pengxiang; Lv, Sulian; Feng, Juanjuan; Li, Yinxin

    2011-05-01

    Inhibition of lycopene cyclization decreased the salt tolerance of the euhalophyte Salicornia europaea L. We isolated a β-lycopene cyclase gene SeLCY from S. europaea and transformed it into Arabidopsis with stable expression. Transgenic Arabidopsis on post-germination exhibited enhanced tolerance to oxidative and salt stress. After 8 and 21 d recovery from 200 mM NaCl treatment, transgenic lines had a higher survival ratio than wild-type (WT) plants. Three-week-old transgenic plants treated with 200 mM NaCl showed better growth than the WT with higher photosystem activity and less H(2)O(2) accumulation. Determination of endogenous pigments of Arabidopsis treated with 200 mM NaCl for 0, 2 or 4 d demonstrated that the transgenic plants retained higher contents of carotenoids than the WT. Furthermore, to compare the difference between SeLCY and AtLCY from Arabidopsis, we used viral vector mediating ectopic expression of SeLCY and AtLCY in Nicotiana benthamiana. Although LCY genes transformation increased the salt tolerance in tobacco, there is no significant difference between SeLCY- and AtLCY-transformed plants. These findings indicate that SeLCY transgenic Arabidopsis improved salt tolerance by increasing synthesis of carotenoids, which impairs reactive oxygen species and protects the photosynthesis system under salt stress, and as a single gene, SeLCY functionally showed no advantage for salt tolerance improvement compared with AtLCY.

  16. Ectopic over-expression of BhHsf1, a heat shock factor from the resurrection plant Boea hygrometrica, leads to increased thermotolerance and retarded growth in transgenic Arabidopsis and tobacco.

    PubMed

    Zhu, Yan; Wang, Zhi; Jing, Yanjun; Wang, Lili; Liu, Xia; Liu, Yongxiu; Deng, Xin

    2009-11-01

    Plant heat shock transcription factors (Hsfs) are commonly found to be involved in various stress responses. Several Hsfs displayed dwarf phenotype while conferred stress tolerance when over-expressed. However, the underlying mechanisms were not fully understood. Here we report the cloning and characterization of an Hsf (BhHsf1) from the resurrection plant Boea hygrometrica. Drought, heat and wound can induce BhHsf1 expression. The over-expression of BhHsf1 conferred growth retardation and stress tolerance in both Arabidopsis and tobacco. Evidence was presented to show that the growth retardation of aerial organs in the transgenic plants was resulted from the reduction of cell proliferation. Gene expression profiling using microarray hybridization and pathway analysis showed that Hsps and stress-associated genes were induced whereas the genes related to DNA replication and mitotic cell cycle were down-regulated in BhHsf1 over-expression Arabidopsis, which was in consistence with the observation of the impaired nuclear endoreduplication. Taking together, our results suggest that BhHsf1 may play dual roles in mediating the processes in heat stress tolerance and growth retardation via regulation of target genes related to stress protection and mitotic cell cycle.

  17. Arabidopsis WIND1 induces callus formation in rapeseed, tomato, and tobacco.

    PubMed

    Iwase, Akira; Mitsuda, Nobutaka; Ikeuchi, Momoko; Ohnuma, Mariko; Koizuka, Chie; Kawamoto, Koich; Imamura, Jun; Ezura, Hiroshi; Sugimoto, Keiko

    2013-01-01

    The capacity to promote cell dedifferentiation is widespread among plant species. We have recently reported that an AP2/ERF transcription factor WOUND INDUCED DEDIFFERENTIATION 1 (WIND1) and its paralogues, WIND2-4, promote cell dedifferentiation in Arabidopsis (Arabidopsis thaliana). Phylogenetic analyses suggest that AtWIND1 orthologs are found in land plants and that the shared peptide motifs between Arabidopsis paralogues are conserved in putative orthologs in dicotyledonous and monocotyledonous plants. In this study we show that AtWIND1 chemically induced rapeseed and tomato, as well as AtWIND1 constitutively expressed tobacco, promote callus formation on phytohormone-free medium. Our results suggest that the WIND1-mediated signaling cascade to promote cell dedifferentiation might be conserved in at least several species of Brassicaceae and Solanaceae.

  18. Transgenic expression of pectin methylesterase inhibitors limits tobamovirus spread in tobacco and Arabidopsis.

    PubMed

    Lionetti, Vincenzo; Raiola, Alessandro; Cervone, Felice; Bellincampi, Daniela

    2014-04-01

    Plant infection by a virus is a complex process influenced by virus-encoded factors and host components which support replication and movement. Critical factors for a successful tobamovirus infection are the viral movement protein (MP) and the host pectin methylesterase (PME), an important plant counterpart that cooperates with MP to sustain viral spread. The activity of PME is modulated by endogenous protein inhibitors (pectin methylesterase inhibitors, PMEIs). PMEIs are targeted to the extracellular matrix and typically inhibit plant PMEs by forming a specific and stable stoichiometric 1:1 complex. PMEIs counteract the action of plant PMEs and therefore may affect plant susceptibility to virus. To test this hypothesis, we overexpressed genes encoding two well-characterized PMEIs in tobacco and Arabidopsis plants. Here, we report that, in tobacco plants constitutively expressing a PMEI from Actinidia chinensis (AcPMEI), systemic movement of Tobacco mosaic virus (TMV) is limited and viral symptoms are reduced. A delayed movement of Turnip vein clearing virus (TVCV) and a reduced susceptibility to the virus were also observed in Arabidopsis plants overexpressing AtPMEI-2. Our results provide evidence that PMEIs are able to limit tobamovirus movement and to reduce plant susceptibility to the virus.

  19. 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.

  20. PHYTOREMEDIATION OF PERCHLORATE BY TOBACCO PLANTS

    EPA Science Inventory

    Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in the plant tissues. The objective of this research was to determine the effectiveness of tobacco plants in phytoremediation, a technology that employs plants to degrade,...

  1. PHYTOREMEDIATION OF PERCHLORATE BY TOBACCO PLANTS

    EPA Science Inventory

    Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in the plant tissues. The objective of this research was to determine the effectiveness of tobacco plants in phytoremediation, a technology that employs plants to degrade,...

  2. The Arabidopsis PLAT domain protein1 promotes abiotic stress tolerance and growth in tobacco.

    PubMed

    Hyun, Tae Kyung; Albacete, Alfonso; van der Graaff, Eric; Eom, Seung Hee; Großkinsky, Dominik K; Böhm, Hannah; Janschek, Ursula; Rim, Yeonggil; Ali, Walid Wahid; Kim, Soo Young; Roitsch, Thomas

    2015-08-01

    Plant growth and consequently crop yield can be severely compromised by abiotic and biotic stress conditions. Transgenic approaches that resulted in increased tolerance against abiotic stresses often were typically accompanied by adverse effects on plant growth and fitness under optimal growing conditions. Proteins that belong to the PLAT-plant-stress protein family harbour a single PLAT (Polycystin, Lipoxygenase, Alpha-toxin and Triacylglycerol lipase) domain and are ubiquitously present in monocot and dicot plant species. Until now, only limited data is available for PLAT-plant-stress family members, which suggested that these proteins in general could promote tolerance towards stress responses. We studied the function of the Arabidopsis PLAT-plant-stress protein AtPLAT1 employing heterologous gain-of-function analysis in tobacco. AtPLAT1 conferred increased abiotic stress tolerance in tobacco, evident by improved tolerance towards cold, drought and salt stresses, and promoted growth, reflected by a faster development under non-stressed conditions. However, the overexpression of AtPLAT1 in tobacco reduced the tolerance towards biotic stress conditions and, therefore, could be involved in regulating the crosstalk between abiotic and biotic stress responses. Thus, we showed that heterologously expressed AtPLAT1 functions as positive regulator of abiotic stress tolerance and plant growth, which could be an important new asset for strategies to develop plants with improved abiotic stress tolerance, without growth and subsequent yield penalties under optimal growth conditions.

  3. Streptomyces scabiei and its toxin thaxtomin A induce scopoletin biosynthesis in tobacco and Arabidopsis thaliana.

    PubMed

    Lerat, Sylvain; Babana, Amadou H; El Oirdi, Mohamed; El Hadrami, Abdelbassed; Daayf, Fouad; Beaudoin, Nathalie; Bouarab, Kamal; Beaulieu, Carole

    2009-12-01

    Streptomyces scabiei is the predominant causal agent of common scab of potato in North America. The virulence of common scab-causing streptomycetes relies on their capacity to synthesize thaxtomins. In this study, the effects of S. scabiei infection and of thaxtomin A, the main toxin produced by S. scabiei, were tested for the elicitation of plant defense molecules in the model plants tobacco (Nicotiana tabacum) and Arabidopsis thaliana. Tobacco leaves infected with spores of S. scabiei strain EF-35 or infiltrated with purified thaxtomin A produced a blue fluorescent compound that was not detected in leaves infiltrated with spores of a S. scabiei mutant deficient in thaxtomin A biosynthesis. Thin layer chromatography and high performance liquid chromatography identified this fluorescent compound as scopoletin, a plant defense phytoalexin. Arabidopsis seedlings grown in liquid medium also excreted scopoletin as a reaction to S. scabiei and thaxtomin A. The effects of the presence of scopoletin on S. scabiei were also investigated. The phytoalexin scopoletin caused a slight reduction of bacterial growth and a severe decrease of thaxtomin A production. Scopoletin was shown to inhibit thaxtomin A production by repression of a gene involved in the toxin biosynthesis.

  4. Splicing of arabidopsis tRNA(Met) precursors in tobacco cell and wheat germ extracts.

    PubMed

    Akama, K; Junker, V; Yukawa, Y; Sugiura, M; Beier, H

    2000-09-01

    Intron-containing tRNA genes are exceptional within nuclear plant genomes. It appears that merely two tRNA gene families coding for tRNA(GpsiA(Tyr)) and elongator tRNA(CmAU(Met)) contain intervening sequences. We have previously investigated the features required by wheat germ splicing endonuclease for efficient and accurate intron excision from Arabidopsis pre-tRNA(Tyr). Here we have studied the expression of an Arabidopsis elongator tRNA(Met) gene in two plant extracts of different origin. This gene was first transcribed either in HeLa or in tobacco cell nuclear extract and splicing of intron-containing tRNA(Met) precursors was then examined in wheat germ S23 extract and in the tobacco system. The results show that conversion of pre-tRNA(Met) to mature tRNA proceeds very efficiently in both plant extracts. In order to elucidate the potential role of specific nucleotides at the 3' and 5' splice sites and of a structured intron for pre-tRNA(Met) splicing in either extract, we have performed a systematic survey by mutational analyses. The results show that cytidine residues at intron-exon boundaries impair pre-tRNA(Met) splicing and that a highly structured intron is indispensable for pre-tRNA(Met) splicing. tRNA precursors with an extended anticodon stem of three to four base pairs are readily accepted as substrates by wheat and tobacco splicing endonuclease, whereas pre-tRNA molecules that can form an extended anticodon stem of only two putative base pairs are not spliced at all. An amber suppressor, generated from the intron-containing elongator tRNA(Met) gene, is efficiently processed and spliced in both plant extracts.

  5. Arabidopsis and Tobacco SUPERMAN regulate hormone signalling and mediate cell proliferation and differentiation

    PubMed Central

    Nibau, Candida; Di Stilio, Verónica S.; Wu, Hen-ming; Cheung, Alice Y.

    2011-01-01

    Arabidopsis thaliana SUPERMAN (SUP) plays an important role during flower development by maintaining the boundary between stamens and carpels in the inner two whorls. It was proposed that SUP maintains this boundary by regulating cell proliferation in both whorls, as loss-of-function superman mutants produce more stamens at the expense of carpels. However, the cellular mechanism that underlies SUP function remains unknown. Here Arabidopsis or tobacco (Nicotiana tabacum) SUP was overexpressed in tobacco plants to substantiate SUP's role as a regulator of cell proliferation and boundary definition and provide evidence that its biological role may be mediated via hormonal changes. It was found that moderate levels of SUP stimulated cell growth and proliferation, whereas high levels were inhibitory. SUP stimulated auxin- and cytokinin-regulated processes, and cells overexpressing SUP displayed reduced hormone dependency for proliferation and regeneration into plants. SUP also induced proliferation of female traits in the second and third flower whorls and promoted differentiation of petaloid properties in sepals, further supporting a role for SUP as a boundary regulator. Moreover, cytokinin suppressed stamen development and promoted differentiation of carpeloid tissues, suggesting that SUP may regulate male and female development via its effect on cytokinin signalling. Taken together, these observations suggest a model whereby the effect of SUP on cell growth and proliferation involves the modulation of auxin- and cytokinin-regulated processes. Furthermore, differential SUP expression or different sensitivities of different cell types to SUP may determine whether SUP stimulates or suppresses their proliferation. PMID:20980362

  6. Arabidopsis and Tobacco superman regulate hormone signalling and mediate cell proliferation and differentiation.

    PubMed

    Nibau, Candida; Di Stilio, Verónica S; Wu, Hen-Ming; Cheung, Alice Y

    2011-01-01

    Arabidopsis thaliana superman (SUP) plays an important role during flower development by maintaining the boundary between stamens and carpels in the inner two whorls. It was proposed that SUP maintains this boundary by regulating cell proliferation in both whorls, as loss-of-function superman mutants produce more stamens at the expense of carpels. However, the cellular mechanism that underlies SUP function remains unknown. Here Arabidopsis or tobacco (Nicotiana tabacum) SUP was overexpressed in tobacco plants to substantiate SUP's role as a regulator of cell proliferation and boundary definition and provide evidence that its biological role may be mediated via hormonal changes. It was found that moderate levels of SUP stimulated cell growth and proliferation, whereas high levels were inhibitory. SUP stimulated auxin- and cytokinin-regulated processes, and cells overexpressing SUP displayed reduced hormone dependency for proliferation and regeneration into plants. SUP also induced proliferation of female traits in the second and third flower whorls and promoted differentiation of petaloid properties in sepals, further supporting a role for SUP as a boundary regulator. Moreover, cytokinin suppressed stamen development and promoted differentiation of carpeloid tissues, suggesting that SUP may regulate male and female development via its effect on cytokinin signalling. Taken together, these observations suggest a model whereby the effect of SUP on cell growth and proliferation involves the modulation of auxin- and cytokinin-regulated processes. Furthermore, differential SUP expression or different sensitivities of different cell types to SUP may determine whether SUP stimulates or suppresses their proliferation.

  7. Ectopic expression of Arabidopsis glycosyltransferase UGT85A5 enhances salt stress tolerance in tobacco.

    PubMed

    Sun, Yan-Guo; Wang, Bo; Jin, Shang-Hui; Qu, Xiao-Xia; Li, Yan-Jie; Hou, Bing-Kai

    2013-01-01

    Abiotic stresses greatly influence plant growth and productivity. While glycosyltransferases are widely distributed in plant kingdom, their biological roles in response to abiotic stresses are largely unknown. In this study, a novel Arabidopsis glycosyltransferase gene UGT85A5 was identified as significantly induced by salt stress. Ectopic expression of UGT85A5 in tobacco enhanced the salt stress tolerance in the transgenic plants. There were higher seed germination rates, better plant growth and less chlorophyll loss in transgenic lines compared to wild type plants under salt stress. This enhanced tolerance of salt stress was correlated with increased accumulations of proline and soluble sugars, but with decreases in malondialdehyde accumulation and Na(+)/K(+) ratio in UGT85A5-expressing tobacco. Furthermore, during salt stress, expression of several carbohydrate metabolism-related genes including those for sucrose synthase, sucrose-phosphate synthase, hexose transporter and a group2 LEA protein were obviously upregulated in UGT85A5-expressing transgenic plants compared with wild type controls. Thus, these findings suggest a specific protective role of this glycosyltransferase against salt stress and provide a genetic engineering strategy to improve salt tolerance of crops.

  8. Evidence for proteolytic processing of tobacco mosaic virus movement protein in Arabidopsis thaliana.

    PubMed

    Hughes, R K; Perbal, M C; Maule, A J; Hull, R

    1995-01-01

    Two ecotypes of Arabidopsis thaliana were transformed with the gene encoding tobacco mosaic virus (TMV) movement protein (P30). P30 accumulated largely in a subcellular fraction containing cell wall components and as a soluble protein. The protein migrated in denaturing gels with an M(r) of 30K, significantly faster than P30 (M(r) approximately 34K) accumulating after expression in transgenic tobacco, Escherichia coli or Spodoptera frugiperda cells, or after virus multiplication in tobacco. The P30 from A. thaliana infected with TMV for 14 days comigrated with that from E. coli, but that from A. thaliana infected for 49 days was of the smaller size. The use of antisera specific for the N- or C-termini of P30 showed that in A. thaliana P30 was proteolytically processed at the N-terminus, a region essential for P30 function. The failure of these plants to complement a TMV P30 mutant indicated that processed P30 was nonfunctional, although the processing was not so rapid that it prevented the development of systemic infections with wild type TMV. The absence of detectable P30 phosphorylation in A. thaliana demonstrated that phosphorylation was not essential for movement protein function and suggested that this species may use proteolytic cleavage of the N-terminus as an alternative strategy to tobacco for deactivating P30.

  9. 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.

  10. 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

  11. Benzoylsalicylic acid isolated from seed coats of Givotia rottleriformis induces systemic acquired resistance in tobacco and Arabidopsis.

    PubMed

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

    2016-06-01

    Systemic acquired resistance (SAR), a whole plant defense response to a broad spectrum of pathogens, is characterized by a coordinated expression of a large number of defense genes. Plants synthesize a variety of secondary metabolites to protect themselves from the invading microbial pathogens. Several studies have shown that salicylic acid (SA) is a key endogenous component of local and systemic disease resistance in plants. Although SA is a critical signal for SAR, accumulation of endogenous SA levels alone is insufficient to establish SAR. Here, we have identified a new acyl derivative of SA, the benzoylsalicylic acid (BzSA) also known as 2-(benzoyloxy) benzoic acid from the seed coats of Givotia rottleriformis and investigated its role in inducing SAR in tobacco and Arabidopsis. Interestingly, exogenous BzSA treatment induced the expression of NPR1 (Non-expressor of pathogenesis-related gene-1) and pathogenesis related (PR) genes. BzSA enhanced the expression of hypersensitivity related (HSR), mitogen activated protein kinase (MAPK) and WRKY genes in tobacco. Moreover, Arabidopsis NahG plants that were treated with BzSA showed enhanced resistance to tobacco mosaic virus (TMV) as evidenced by reduced leaf necrosis and TMV-coat protein levels in systemic leaves. We, therefore, conclude that BzSA, hitherto unknown natural plant product, is a new SAR inducer in plants.

  12. Ectopic expression of a tobacco vacuolar invertase inhibitor in guard cells confers drought tolerance in Arabidopsis.

    PubMed

    Chen, Su-Fen; Liang, Ke; Yin, Dong-Mei; Ni, Di-An; Zhang, Zhi-Guo; Ruan, Yong-Ling

    2016-12-01

    There are several hypotheses that explain stomatal behavior. These include the concept of osmoregulation mediated by potassium and its counterions malate and chlorine and the more recent starch-sugar hypothesis. We have previously reported that the activity of the sucrose cleavage enzyme, vacuolar invertase (VIN), is significantly higher in guard cells than in other leaf epidermal cells and its activity is correlated with stomatal aperture. Here, we examined whether VIN indeed controls stomatal movement under normal and drought conditions by transforming Arabidopsis with a tobacco vacuolar invertase inhibitor homolog (Nt-inhh) under the control of an abscisic acid-sensitive and guard cell-specific promoter (AtRab18). The data obtained showed that guard cells of transgenic Arabidopsis plants had lower VIN activity, stomatal aperture and conductance than that of wild-type plants. Moreover, the transgenic plants also displayed higher drought tolerance than wild-type plants. The data indicate that VIN is a promising target for manipulating stomatal function to increase drought tolerance.

  13. Arabidopsis TTR1 causes LRR-dependent lethal systemic necrosis, rather than systemic acquired resistance, to Tobacco ringspot virus

    USDA-ARS?s Scientific Manuscript database

    Most Arabidopsis ecotypes display tolerance to the Tobacco ringspot virus (TRSV), but a subset of Arabidopsis ecotypes, including Estland (Est), develop lethal systemic necrosis (LSN), which differs from the localized hypersensitive responses (HRs) or systemic acquired resistance (SAR) characteristi...

  14. Infection of Plants by Tobacco Mosaic Virus.

    ERIC Educational Resources Information Center

    McDaniel, Larry; Maratos, Marina; Farabaugh, Joan

    1998-01-01

    Provides three exercises that introduce high school and college students to a common strain of the tobacco mosaic virus and the study of some basic biological processes. Activities involve inoculation of plants and observing and recording symptom development in infected plants. (DDR)

  15. Infection of Plants by Tobacco Mosaic Virus.

    ERIC Educational Resources Information Center

    McDaniel, Larry; Maratos, Marina; Farabaugh, Joan

    1998-01-01

    Provides three exercises that introduce high school and college students to a common strain of the tobacco mosaic virus and the study of some basic biological processes. Activities involve inoculation of plants and observing and recording symptom development in infected plants. (DDR)

  16. Enzymatic transamination of pyridoxamine in tobacco plants.

    PubMed

    Huang, ShuoHao; Zhang, JianYun; Wu, Mei; Wu, Qiong; Huang, LongQuan

    2013-11-01

    Vitamin B6 (VB6) comprises a group of pyridine compounds that are involved in a surprisingly high diversity of biochemical reactions. Humans and animals depend largely on plants for their VB6 nutrition. Many studies have focused on biosynthesis of VB6 and comparatively little is known about VB6 metabolic conversion in plants. Recently, we have found that an efficient conversion pathway between pyridoxal (PL) and pyridoxamine (PM) is present in tobacco, but the catalytic enzyme remains an unsolved mystery. In this study, enzymes catalyzing the transamination of PM were purified from tobacco leaves and characterized. Our results suggest that a specific PM-pyruvate aminotranferase dominates the reversible transamination of PM in tobacco, and also show that the apo form of glutamic-oxaloacetic aminotranferase from tobacco, but not the holoenzyme, is able to catalyze the analogous transamination reaction between PM and either oxaloacetate or α-ketoglutarate. PM-pyruvate aminotranferase is involved in a degradation pathway for VB6 compounds in bacteria. Therefore, our study raises questions about whether the degradation pathway of VB6 exists in plants.

  17. Diuretics prime plant immunity in Arabidopsis thaliana.

    PubMed

    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.

  18. 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

  19. Suppression of cell expansion by ectopic expression of the Arabidopsis SUPERMAN gene in transgenic petunia and tobacco.

    PubMed

    Kater, M M; Franken, J; van Aelst, A; Angenent, G C

    2000-08-01

    Molecular and genetic analyses have shown that the Arabidopsis thaliana gene SUPERMAN (SUP) has at least two functions in Arabidopsis flower development. SUP is necessary to control the correct distribution of cells with either a stamen or carpel fate, and is essential for proper outgrowth of the ovule outer integument. Both these functions indicate a role for SUP in cell proliferation. To study the function of the Arabidopsis SUP gene in more detail, we over-expressed the SUP gene in petunia and tobacco in a tissue-specific manner. The petunia FLORAL BINDING PROTEIN 1 (FBP1) gene promoter was used to restrict the expression of SUP to petals and stamens. The development of petals and stamens was severely affected in both petunia and tobacco plants over-expressing SUP. Petals remained small and did not unfold, resulting in closed flowers. Stamen filaments were thin and very short. Detailed analysis of these floral organs from the petunia transformants showed that cell expansion was dramatically reduced without affecting cell division. These results reveal a novel activity for SUP as a regulator of cell expansion.

  20. Restoration of stamen development and production of functional pollen in an alloplasmic CMS tobacco line by ectopic expression of the Arabidopsis thaliana SUPERMAN gene.

    PubMed

    Bereterbide, Agnès; Hernould, Michel; Farbos, Isabelle; Glimelius, Kristina; Mouras, Armand

    2002-03-01

    The alloplasmic male-sterile tobacco line Nta(rep)S, combining the nucleus of Nicotiana tabacum with the cytoplasm of Nicotiana repanda, exhibits cadastral-type anomalies due to a fusion of several stamens with the pistil. These anomalies share similarities with Arabidopsis superman mutants. SUPERMAN (SUP) is a cadastral gene controlling the boundary between whorls 3 (androecium) and 4 (gynoecium). Thus we hypothesized that the expression of the tobacco SUP orthologue might be impaired in the alloplasmic Nta(rep)S line, and that the deficiency could be complemented by the Arabidopsis SUP gene. Here we show that the ectopic expression of SUP in the alloplasmic male-sterile tobacco line Nta(rep)S significantly increases the frequency of flowers possessing free stamens, inducing the recovery of a proper structure for whorls 3 and 4. Furthermore, flowers of transgenic plants show a significant improvement of the morphology of stamens, and more particularly of the anthers, which are able to produce few but functional pollen. The data show that ectopic expression of Arabidopsis SUP reactivates the regulatory cascade of anther development. The plausible causes of the developmental defects of anthers in the alloplasmic male-sterile tobacco line are discussed in relation to the model of regulation of the Arabidopsis SUP gene.

  1. Metal accumulation in tobacco expressing Arabidopsis halleri metal hyperaccumulation gene depends on external supply

    PubMed Central

    Barabasz, Anna; Krämer, Ute; Hanikenne, Marc; Rudzka, Justyna; Antosiewicz, Danuta Maria

    2010-01-01

    Engineering enhanced transport of zinc to the aerial parts of plants is a major goal in bio-fortification. In Arabidopsis halleri, high constitutive expression of the AhHMA4 gene encoding a metal pump of the P1B-ATPase family is necessary for both Zn hyperaccumulation and the full extent of Zn and Cd hypertolerance that are characteristic of this species. In this study, an AhHMA4 cDNA was introduced into N. tabacum var. Xanthi for expression under the control of its endogenous A. halleri promoter known to confer high and cell-type specific expression levels in both A. halleri and the non-hyperaccumulator A. thaliana. The transgene was expressed at similar levels in both roots and shoots upon long-term exposure to low Zn, control, and increased Zn concentrations. A down-regulation of AhHMA4 transcript levels was detected with 10 μM Zn resupply to tobacco plants cultivated in low Zn concentrations. In general, a transcriptional regulation of AhHMA4 in tobacco contrasted with the constitutively high expression previously observed in A. halleri. Differences in root/shoot partitioning of Zn and Cd between transgenic lines and the wild type were strongly dependent on metal concentrations in the hydroponic medium. Under low Zn conditions, an increased Zn accumulation in the upper leaves in the AhHMA4-expressing lines was detected. Moreover, transgenic plants exposed to cadmium accumulated less metal than the wild type. Both modifications of zinc and cadmium accumulation are noteworthy outcomes from the biofortification perspective and healthy food production. Expression of AhHMA4 may be useful in crops grown on soils poor in Zn. PMID:20484319

  2. Metal accumulation in tobacco expressing Arabidopsis halleri metal hyperaccumulation gene depends on external supply.

    PubMed

    Barabasz, Anna; Krämer, Ute; Hanikenne, Marc; Rudzka, Justyna; Antosiewicz, Danuta Maria

    2010-06-01

    Engineering enhanced transport of zinc to the aerial parts of plants is a major goal in bio-fortification. In Arabidopsis halleri, high constitutive expression of the AhHMA4 gene encoding a metal pump of the P(1B)-ATPase family is necessary for both Zn hyperaccumulation and the full extent of Zn and Cd hypertolerance that are characteristic of this species. In this study, an AhHMA4 cDNA was introduced into N. tabacum var. Xanthi for expression under the control of its endogenous A. halleri promoter known to confer high and cell-type specific expression levels in both A. halleri and the non-hyperaccumulator A. thaliana. The transgene was expressed at similar levels in both roots and shoots upon long-term exposure to low Zn, control, and increased Zn concentrations. A down-regulation of AhHMA4 transcript levels was detected with 10 muM Zn resupply to tobacco plants cultivated in low Zn concentrations. In general, a transcriptional regulation of AhHMA4 in tobacco contrasted with the constitutively high expression previously observed in A. halleri. Differences in root/shoot partitioning of Zn and Cd between transgenic lines and the wild type were strongly dependent on metal concentrations in the hydroponic medium. Under low Zn conditions, an increased Zn accumulation in the upper leaves in the AhHMA4-expressing lines was detected. Moreover, transgenic plants exposed to cadmium accumulated less metal than the wild type. Both modifications of zinc and cadmium accumulation are noteworthy outcomes from the biofortification perspective and healthy food production. Expression of AhHMA4 may be useful in crops grown on soils poor in Zn.

  3. ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS: DEVELOPMENT OF A PLANT KINETIC MODEL

    EPA Science Inventory

    Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in plant tissues. This research determined the uptake, translocation, and accumulation of perchlorate in tobacco plants. Three hydroponics growth studies were completed u...

  4. ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS: DEVELOPMENT OF A PLANT KINETIC MODEL

    EPA Science Inventory

    Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in plant tissues. This research determined the uptake, translocation, and accumulation of perchlorate in tobacco plants. Three hydroponics growth studies were completed u...

  5. Virus-Induced Alterations in Primary Metabolism Modulate Susceptibility to Tobacco rattle virus in Arabidopsis1[C][W

    PubMed Central

    Fernández-Calvino, Lourdes; Osorio, Sonia; Hernández, M. Luisa; Hamada, Ignacio B.; del Toro, Francisco J.; Donaire, Livia; Yu, Agnés; Bustos, Regla; Fernie, Alisdair R.; Martínez-Rivas, José M.; Llave, César

    2014-01-01

    During compatible virus infections, plants respond by reprogramming gene expression and metabolite content. While gene expression studies are profuse, our knowledge of the metabolic changes that occur in the presence of the virus is limited. Here, we combine gene expression and metabolite profiling in Arabidopsis (Arabidopsis thaliana) infected with Tobacco rattle virus (TRV) in order to investigate the influence of primary metabolism on virus infection. Our results revealed that primary metabolism is reconfigured in many ways during TRV infection, as reflected by significant changes in the levels of sugars and amino acids. Multivariate data analysis revealed that these alterations were particularly conspicuous at the time points of maximal accumulation of TRV, although infection time was the dominant source of variance during the process. Furthermore, TRV caused changes in lipid and fatty acid composition in infected leaves. We found that several Arabidopsis mutants deficient in branched-chain amino acid catabolism or fatty acid metabolism possessed altered susceptibility to TRV. Finally, we showed that increments in the putrescine content in TRV-infected plants correlated with enhanced tolerance to freezing stress in TRV-infected plants and that impairment of putrescine biosynthesis promoted virus multiplication. Our results thus provide an interesting overview for a better understanding of the relationship between primary metabolism and virus infection. PMID:25358898

  6. Comparative analysis of the plant mRNA-destabilizing element, DST, in mammalian and tobacco cells.

    PubMed

    Feldbrügge, M; Arizti, P; Sullivan, M L; Zamore, P D; Belasco, J G; Green, P J

    2002-05-01

    The labile SAUR transcripts from higher plants contain a conserved DST sequence in their 3'-untranslated regions. Two copies of a DST sequence from soybean are sufficient to destabilize reporter transcripts in cultured tobacco cells whereas variants bearing mutations in the conserved ATAGAT or GTA regions are inactive. To investigate the potential for conserved recognition components in mammalian and plant cells, we examined the function of this instability determinant in mouse NIH3T3 fibroblasts and tobacco BY2 cells. In fibroblasts, a tetrameric DST element from soybean accelerated deadenylation and decay of a reporter transcript. However, a version mutated in the ATAGAT region was equally effective in this regard, and a tetrameric DST element from Arabidopsis was inactive. In contrast, the soybean DST element was more active as an mRNA instability element than the mutant version and the Arabidopsis element, when tested as tetramers in tobacco cells. Hence, the plant DST element is not recognized in animal cells with the same sequence requirements as in plant cells. Therefore, its mode of recognition appears to be plant-specific.

  7. [Effect of constitutive expression of ARGOS-LIKE gene on dimensions of cells and organs of transgenic tobacco plants].

    PubMed

    Kuluev, B R; Khiazev, A V; Safiullina, M G; Cemeris, A V

    2013-05-01

    Transgenic tobacco plants that overexpress the ARGOS-LIKE (ARL) gene of Arabidopsis thaliana have been developed. The transgenic plants possessed increased dimensions of leaves and stem, whereas the magnitude of flowers was modified to a lesser degree. The increase in the organ dimensions was a result of stimulation of cell expansion; the cell quantity in the organ was even decreased. Ectopic expression of the ARL gene was promoted in order to increase in the level of mRNA of tobacco expansine NtEXPA5. It has been shown that the ARL gene of A. thaliana can be used to obtain transgenic plants with increased sizes of the leaves and stem.

  8. β-1,3 Glucan Sulfate, but Not β-1,3 Glucan, Induces the Salicylic Acid Signaling Pathway in Tobacco and Arabidopsis

    PubMed Central

    Ménard, Rozenn; Alban, Susanne; de Ruffray, Patrice; Jamois, Frank; Franz, Gerhard; Fritig, Bernard; Yvin, Jean-Claude; Kauffmann, Serge

    2004-01-01

    Sulfate substituents naturally occurring in biomolecules, such as oligosaccharides and polysaccharides, can play a critical role in major physiological functions in plants and animals. We show that laminarin, a β-1,3 glucan with elicitor activity in tobacco (Nicotiana tabacum), becomes, after chemical sulfation, an inducer of the salicylic acid (SA) signaling pathway in tobacco and Arabidopsis thaliana. In tobacco cell suspensions, the oxidative burst induced by the laminarin sulfate PS3 was Ca2+ dependent but partially kinase independent, whereas laminarin triggered a strickly kinase-dependent oxidative burst. Cells treated with PS3 or laminarin remained fully responsive to a second application of laminarin or PS3, respectively, suggesting two distinct perception systems. In tobacco leaves, PS3, but not laminarin, caused electrolyte leakage and triggered scopoletin and SA accumulation. Expression of different families of Pathogenesis-Related (PR) proteins was analyzed in wild-type and mutant tobacco as well as in Arabidopsis. Laminarin induced expression of ethylene-dependent PR proteins, whereas PS3 triggered expression of ethylene- and SA-dependent PR proteins. In Arabidopsis, PS3-induced PR1 expression was also NPR1 (for nonexpressor of PR genes1) dependent. Structure-activity analysis revealed that (1) a minimum chain length is essential for biological activity of unsulfated as well as sulfated laminarin, (2) the sulfate residues are essential and cannot be replaced by other anionic groups, and (3) moderately sulfated β-1,3 glucans are active. In tobacco, PS3 and curdlan sulfate induced immunity against Tobacco mosaic virus infection, whereas laminarin induced only a weak resistance. The results open new routes to work out new molecules suitable for crop protection. PMID:15494557

  9. Changes in the gene expression profile of Arabidopsis thaliana after infection with Tobacco etch virus

    PubMed Central

    Agudelo-Romero, Patricia; Carbonell, Pablo; de la Iglesia, Francisca; Carrera, Javier; Rodrigo, Guillermo; Jaramillo, Alfonso; Pérez-Amador, Miguel A; Elena, Santiago F

    2008-01-01

    Background Tobacco etch potyvirus (TEV) has been extensively used as model system for the study of positive-sense RNA virus infecting plants. TEV ability to infect Arabidopsis thaliana varies among ecotypes. In this study, changes in gene expression of A. thaliana ecotype Ler infected with TEV have been explored using long-oligonucleotide arrays. A. thaliana Ler is a susceptible host that allows systemic movement, although the viral load is low and syndrome induced ranges from asymptomatic to mild. Gene expression profiles were monitored in whole plants 21 days post-inoculation (dpi). Microarrays contained 26,173 protein-coding genes and 87 miRNAs. Results Expression analysis identified 1727 genes that displayed significant and consistent changes in expression levels either up or down, in infected plants. Identified TEV-responsive genes encode a diverse array of functional categories that include responses to biotic (such as the systemic acquired resistance pathway and hypersensitive responses) and abiotic stresses (droughtness, salinity, temperature, and wounding). The expression of many different transcription factors was also significantly affected, including members of the R2R3-MYB family and ABA-inducible TFs. In concordance with several other plant and animal viruses, the expression of heat-shock proteins (HSP) was also increased. Finally, we have associated functional GO categories with KEGG biochemical pathways, and found that many of the altered biological functions are controlled by changes in basal metabolism. Conclusion TEV infection significantly impacts a wide array of cellular processes, in particular, stress-response pathways, including the systemic acquired resistance and hypersensitive responses. However, many of the observed alterations may represent a global response to viral infection rather than being specific of TEV. PMID:18684336

  10. Transcript Profiling of Different Arabidopsis thaliana Ecotypes in Response to Tobacco etch potyvirus Infection

    PubMed Central

    Hillung, Julia; Cuevas, José M.; Elena, Santiago F.

    2012-01-01

    The use of high-throughput transcript profiling techniques has opened the possibility of identifying, in a single experiment, multiple host mRNAs whose levels of accumulation are altered in response to virus infection. Several studies have used this approach to analyze the response of Arabidopsis thaliana to the infection by different RNA and DNA viruses. However, the possible differences in response of genetically heterogeneous ecotypes of the plant to the same virus have never been addressed before. Here we have used a strain of Tobacco etch potyvirus (TEV) experimentally adapted to A. thaliana ecotype Ler-0 and a set of seven plant ecotypes to tackle this question. Each ecotype was inoculated with the same amount of the virus and the outcome of infection characterized phenotypically (i.e., virus infectivity, accumulation, and symptoms development). Using commercial microarrays containing probes for more than 43,000 A. thaliana transcripts, we explored the effect of viral infection on the plant transcriptome. In general, we found that ecotypes differ in the way they perceive and respond to the virus. Some ecotypes developed strong symptoms and accumulated large amounts of viral genomes, while others only developed mild symptoms and accumulated less virus. At the transcriptomic level, ecotypes could be classified into two groups according to the particular genes whose expression was altered upon infection. Moreover, a functional enrichment analyses showed that the two groups differed in the nature of the altered biological processes. For the group constituted by ecotypes developing milder symptoms and allowing for lower virus accumulation, genes involved in abiotic stresses and in the construction of new tissues tend to be up-regulated. For those ecotypes in which infection was more severe and productive, defense genes tend to be up-regulated, deviating the necessary resources from building new tissues. PMID:22737149

  11. Transcript Profiling of Different Arabidopsis thaliana Ecotypes in Response to Tobacco etch potyvirus Infection.

    PubMed

    Hillung, Julia; Cuevas, José M; Elena, Santiago F

    2012-01-01

    The use of high-throughput transcript profiling techniques has opened the possibility of identifying, in a single experiment, multiple host mRNAs whose levels of accumulation are altered in response to virus infection. Several studies have used this approach to analyze the response of Arabidopsis thaliana to the infection by different RNA and DNA viruses. However, the possible differences in response of genetically heterogeneous ecotypes of the plant to the same virus have never been addressed before. Here we have used a strain of Tobacco etch potyvirus (TEV) experimentally adapted to A. thaliana ecotype Ler-0 and a set of seven plant ecotypes to tackle this question. Each ecotype was inoculated with the same amount of the virus and the outcome of infection characterized phenotypically (i.e., virus infectivity, accumulation, and symptoms development). Using commercial microarrays containing probes for more than 43,000 A. thaliana transcripts, we explored the effect of viral infection on the plant transcriptome. In general, we found that ecotypes differ in the way they perceive and respond to the virus. Some ecotypes developed strong symptoms and accumulated large amounts of viral genomes, while others only developed mild symptoms and accumulated less virus. At the transcriptomic level, ecotypes could be classified into two groups according to the particular genes whose expression was altered upon infection. Moreover, a functional enrichment analyses showed that the two groups differed in the nature of the altered biological processes. For the group constituted by ecotypes developing milder symptoms and allowing for lower virus accumulation, genes involved in abiotic stresses and in the construction of new tissues tend to be up-regulated. For those ecotypes in which infection was more severe and productive, defense genes tend to be up-regulated, deviating the necessary resources from building new tissues.

  12. Localization of green fluorescent protein fusions with the seven Arabidopsis vacuolar sorting receptors to prevacuolar compartments in tobacco BY-2 cells.

    PubMed

    Miao, Yansong; Yan, Pak Kan; Kim, Hyeran; Hwang, Inhwan; Jiang, Liwen

    2006-11-01

    We have previously demonstrated that vacuolar sorting receptor (VSR) proteins are concentrated on prevacuolar compartments (PVCs) in plant cells. PVCs in tobacco (Nicotiana tabacum) BY-2 cells are multivesicular bodies (MVBs) as defined by VSR proteins and the BP-80 reporter, where the transmembrane domain (TMD) and cytoplasmic tail (CT) sequences of BP-80 are sufficient and specific for correct targeting of the reporter to PVCs. The genome of Arabidopsis (Arabidopsis thaliana) contains seven VSR proteins, but little is known about their individual subcellular localization and function. Here, we study the subcellular localization of the seven Arabidopsis VSR proteins (AtVSR1-7) based on the previously proven hypothesis that the TMD and CT sequences correctly target individual VSR to its final destination in transgenic tobacco BY-2 cells. Toward this goal, we have generated seven chimeric constructs containing signal peptide (sp) linked to green fluorescent protein (GFP) and TMD/CT sequences (sp-GFP-TMD/CT) of the seven individual AtVSR. Transgenic tobacco BY-2 cell lines expressing these seven sp-GFP-TMD-CT fusions all exhibited typical punctate signals colocalizing with VSR proteins by confocal immunofluorescence. In addition, wortmannin caused the GFP-marked prevacuolar organelles to form small vacuoles, and VSR antibodies labeled these enlarged MVBs in transgenic BY-2 cells. Wortmannin also caused VSR-marked PVCs to vacuolate in other cell types, including Arabidopsis, rice (Oryza sativa), pea (Pisum sativum), and mung bean (Vigna radiata). Therefore, the seven AtVSRs are localized to MVBs in tobacco BY-2 cells, and wortmannin-induced vacuolation of PVCs is a general response in plants.

  13. Stomatal Closure and Rise in ROS/NO of Arabidopsis Guard Cells by Tobacco Microbial Elicitors: Cryptogein and Harpin

    PubMed Central

    Gayatri, Gunja; Agurla, Srinivas; Kuchitsu, Kazuyuki; Anil, Kondreddy; Podile, Appa R.; Raghavendra, Agepati S.

    2017-01-01

    Plants use stomatal closure mediated by elicitors as the first step of the innate immune response to restrict the microbial entry. We present a comprehensive study of the effect of cryptogein and harpin, two elicitors from microbial pathogens of tobacco, on stomatal closure and guard cell signaling components in Arabidopsis thaliana, a model plant. Cryptogein as well as harpin induced stomatal closure, while elevating the levels of reactive oxygen species (ROS) and nitric oxide (NO) in the guard cells of A. thaliana. Kinetic studies with fluorescent dyes revealed that the rise in ROS levels preceded that of NO in guard cells, when treated with these two elicitors. The restriction of NO levels in guard cells, even by ROS modulators indicates the essentiality of ROS for NO production during elicitor-triggered stomatal closure. The signaling events during elicitor-induced stomatal closure appear to converge at NADPH oxidase and ROS production. Our results provide the first report on stomatal closure associated with rise in ROS/NO of guard cells by cryptogein and harpin in A. thaliana. Our results establish that A. thaliana can be used to study stomatal responses to the typical elicitors from microbial pathogens of other plants. The suitability of Arabidopsis opens up an excellent scope for further studies on signaling events leading to stomatal closure by microbial elicitors. PMID:28680439

  14. The development of Arabidopsis as a model plant.

    PubMed

    Koornneef, Maarten; Meinke, David

    2010-03-01

    Twenty-five years ago, Arabidopsis thaliana emerged as the model organism of choice for research in plant biology. A consensus was reached about the need to focus on a single organism to integrate the classical disciplines of plant science with the expanding fields of genetics and molecular biology. Ten years after publication of its genome sequence, Arabidopsis remains the standard reference plant for all of biology. We reflect here on the major advances and shared resources that led to the extraordinary growth of the Arabidopsis research community. We also underscore the importance of continuing to expand and refine our detailed knowledge of Arabidopsis while seeking to appreciate the remarkable diversity that characterizes the plant kingdom.

  15. Exclusion of plastid nucleoids and ribosomes from stromules in tobacco and Arabidopsis.

    PubMed

    Newell, Christine A; Natesan, Senthil K A; Sullivan, James A; Jouhet, Juliette; Kavanagh, Tony A; Gray, John C

    2012-02-01

    Stromules are stroma-filled tubules that extend from the surface of plastids and allow the transfer of proteins as large as 550 kDa between interconnected plastids. The aim of the present study was to determine if plastid DNA or plastid ribosomes are able to enter stromules, potentially permitting the transfer of genetic information between plastids. Plastid DNA and ribosomes were marked with green fluorescent protein (GFP) fusions to LacI, the lac repressor, which binds to lacO-related sequences in plastid DNA, and to plastid ribosomal proteins Rpl1 and Rps2, respectively. Fluorescence from GFP-LacI co-localised with plastid DNA in nucleoids in all tissues of transgenic tobacco (Nicotiana tabacum L.) examined and there was no indication of its presence in stromules, not even in hypocotyl epidermal cells, which contain abundant stromules. Fluorescence from Rpl1-GFP and Rps2-GFP was also observed in a punctate pattern in chloroplasts of tobacco and Arabidopsis [Arabidopsis thaliana (L.) Heynh.], and fluorescent stromules were not detected. Rpl1-GFP was shown to assemble into ribosomes and was co-localised with plastid DNA. In contrast, in hypocotyl epidermal cells of dark-grown Arabidopsis seedlings, fluorescence from Rpl1-GFP was more evenly distributed in plastids and was observed in stromules on a total of only four plastids (<0.02% of the plastids observed). These observations indicate that plastid DNA and plastid ribosomes do not routinely move into stromules in tobacco and Arabidopsis, and suggest that transfer of genetic information by this route is likely to be a very rare event, if it occurs at all.

  16. Identification of likely orthologs of tobacco salicylic acid-binding protein 2 and their role in systemic acquired resistance in Arabidopsis thaliana.

    PubMed

    Vlot, Anna Corina; Liu, Po-Pu; Cameron, Robin K; Park, Sang-Wook; Yang, Yue; Kumar, Dhirendra; Zhou, Fasong; Padukkavidana, Thihan; Gustafsson, Claes; Pichersky, Eran; Klessig, Daniel F

    2008-11-01

    Salicylic acid-binding protein 2 (SABP2) is essential for the establishment of systemic acquired resistance (SAR) in tobacco; SABP2's methyl salicylate (MeSA) esterase activity is required in healthy systemic tissues of infected plants to release the active defense phytohormone SA from MeSA, which serves as a long-distance signal for SAR. In the current study, we characterize a new gene family from Arabidopsis thaliana encoding 18 potentially active alpha/beta fold hydrolases that share 32-57% identity with SABP2. Of 14 recombinant AtMES (MES for methyl esterase) proteins tested, five showed preference for MeSA as a substrate and displayed SA inhibition of MeSA esterase activity in vitro (AtMES1, -2, -4, -7, and -9). The two genes encoding MeSA esterases with the greatest activity, AtMES1 and -9, as well as AtMES7 were transcriptionally upregulated during infection of Arabidopsis with avirulent Pseudomonas syringae. In addition, conditional expression of AtMES1, -7, or -9 complemented SAR deficiency in SABP2-silenced tobacco, suggesting that these three members of the AtMES family are SABP2 functional homologs (orthologs). Underexpression by knockout mutation and/or RNAi-mediated silencing of multiple AtMES genes, including AtMES1, -2, -7, and -9, compromised SAR in Arabidopsis and correlated with enhanced accumulation of MeSA in the systemic tissue of SAR-induced plants. Together, the data show that several members of the AtMES gene family are functionally homologous to SABP2 and redundant for MeSA hydrolysis and probably SAR. These data suggest that MeSA is a conserved SAR signal in Arabidopsis and tobacco.

  17. Hybrid Rubisco of tomato large subunits and tobacco small subunits is functional in tobacco plants.

    PubMed

    Zhang, Xing-Hai; Webb, James; Huang, Yi-Hong; Lin, Li; Tang, Ri-Sheng; Liu, Aimin

    2011-03-01

    Biogenesis of functional ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in plants requires specific assembly in the chloroplast of the imported, cytosol-synthesized small subunits (SS) with the chloroplast-made large subunits (LS). Accumulating evidence indicates that chloroplasts (plastids) generally have a low tolerance for assembling foreign or modified Rubisco. To explore Rubisco engineering, we created two lines of transplastomic tobacco plants whose rbcL gene was replaced by tomato-derived rbcL: plant LLS2 with Rubisco composed of tobacco SS and Q437R LS and plant LLS4 with a hybrid Rubisco of tobacco SS and tomato LS (representing four substitutions of Y226F, A230T, S279T and Q437R from tobacco LS). Plant LLS2 exhibited similar phenotypes as the wild type. Plant LLS4 showed lower chlorophyll and Rubisco levels particularly in young emerging leaves, lower photosynthesis rates and biomass during early stages of development, but was able to reach reproductive maturity and somewhat wild type-like phenotype under ambient CO₂ condition. In vitro assays detected similar carboxylase activity and RuBP affinity in LLS2 and LLS4 plants as in wild type. Our studies demonstrated that tomato LS was sufficiently assembled with tobacco SS into functional Rubisco. The hybrid Rubisco of tomato LS and tobacco SS can drive photosynthesis that supports photoautotrophic growth and reproduction of tobacco plants under ambient CO₂ and light conditions. We discuss the effect of these residue substitutions on Rubisco activity and the possible attribution of chlorophyll deficiency to the in planta photosynthesis performance in the hybrid Rubisco plants.

  18. Single molecule PCR reveals similar patterns of non-homologous DSB repair in tobacco and Arabidopsis.

    PubMed

    Lloyd, Andrew H; Wang, Dong; Timmis, Jeremy N

    2012-01-01

    DNA double strand breaks (DSBs) occur constantly in eukaryotes. These potentially lethal DNA lesions are repaired efficiently by two major DSB repair pathways: homologous recombination and non-homologous end joining (NHEJ). We investigated NHEJ in Arabidopsis thaliana and tobacco (Nicotiana tabacum) by introducing DNA double-strand breaks through inducible expression of I-SceI, followed by amplification of individual repair junction sequences by single-molecule PCR. Using this process over 300 NHEJ repair junctions were analysed in each species. In contrast to previously published variation in DSB repair between Arabidopsis and tobacco, the two species displayed similar DSB repair profiles in our experiments. The majority of repair events resulted in no loss of sequence and small (1-20 bp) deletions occurred at a minority (25-45%) of repair junctions. Approximately ~1.5% of the observed repair events contained larger deletions (>20 bp) and a similar percentage contained insertions. Strikingly, insertion events in tobacco were associated with large genomic deletions at the site of the DSB that resulted in increased micro-homology at the sequence junctions suggesting the involvement of a non-classical NHEJ repair pathway. The generation of DSBs through inducible expression of I-SceI, in combination with single molecule PCR, provides an effective and efficient method for analysis of individual repair junctions and will prove a useful tool in the analysis of NHEJ.

  19. Engineering Herbicide Metabolism in Tobacco and Arabidopsis with CYP76B1, a Cytochrome P450 Enzyme from Jerusalem Artichoke1

    PubMed Central

    Didierjean, Luc; Gondet, Laurence; Perkins, Roberta; Lau, Sze-Mei Cindy; Schaller, Hubert; O'Keefe, Daniel P.; Werck-Reichhart, Danièle

    2002-01-01

    The Jerusalem artichoke (Helianthus tuberosus) xenobiotic inducible cytochrome P450, CYP76B1, catalyzes rapid oxidative dealkylation of various phenylurea herbicides to yield nonphytotoxic metabolites. We have found that increased herbicide metabolism and tolerance can be achieved by ectopic constitutive expression of CYP76B1 in tobacco (Nicotiana tabacum) and Arabidopsis. Transformation with CYP76B1 conferred on tobacco and Arabidopsis a 20-fold increase in tolerance to linuron, a compound detoxified by a single dealkylation, and a 10-fold increase in tolerance to isoproturon or chlortoluron, which need successive catalytic steps for detoxification. Two constructs for expression of translational fusions of CYP76B1 with P450 reductase were prepared to test if they would yield even greater herbicide tolerance. Plants expressing these constructs had lower herbicide tolerance than CYP76B1 alone, which is apparently a consequence of reduced stability of the fusion proteins. In all cases, increased herbicide tolerance results from more extensive metabolism, as demonstrated with exogenously fed phenylurea. Beside increased herbicide tolerance, expression of CYP76B1 has no other visible phenotype in the transgenic plants. Our data indicate that CYP76B1 can function as a selectable marker for plant transformation, allowing efficient selection in vitro and in soil-grown plants. Plants expressing CYP76B1 may also be a potential tool for phytoremediation of contaminated sites. PMID:12226498

  20. Descendants of primed Arabidopsis plants exhibit resistance to biotic stress.

    PubMed

    Slaughter, Ana; Daniel, Xavier; Flors, Victor; Luna, Estrella; Hohn, Barbara; Mauch-Mani, Brigitte

    2012-02-01

    An attack of plants by pathogens or treatment with certain resistance-inducing compounds can lead to the establishment of a unique primed state of defense. Primed plants show enhanced defense reactions upon further challenge with biotic or abiotic stress. Here, we report that the primed state in Arabidopsis (Arabidopsis thaliana) is still functional in the next generation without additional treatment. We compared the reactions of Arabidopsis plants that had been either primed with β-amino-butyric acid (BABA) or with an avirulent isolate of the bacteria Pseudomonas syringae pv tomato (PstavrRpt2). The descendants of primed plants showed a faster and higher accumulation of transcripts of defense-related genes in the salicylic acid signaling pathway and enhanced disease resistance upon challenge inoculation with a virulent isolate of P. syringae. In addition, the progeny of primed plants was also more resistant against the oomycete pathogen Hyaloperonospora arabidopsidis. When transgenerationally primed plants were subjected to an additional priming treatment, their descendants displayed an even stronger primed phenotype, suggesting that plants can inherit a sensitization for the priming phenomenon. Interestingly, this primed to be primed phenotype was much reduced in the Arabidopsis β-amino-butyric acid priming mutant ibs1 (induced BABA sterility1). Our results demonstrate that the primed state of plants is transferred to their progeny and confers improved protection from pathogen attack as compared to the descendants of unprimed plants.

  1. Plant chip for high-throughput phenotyping of Arabidopsis.

    PubMed

    Jiang, Huawei; Xu, Zhen; Aluru, Maneesha R; Dong, Liang

    2014-04-07

    We report on the development of a vertical and transparent microfluidic chip for high-throughput phenotyping of Arabidopsis thaliana plants. Multiple Arabidopsis seeds can be germinated and grown hydroponically over more than two weeks in the chip, thus enabling large-scale and quantitative monitoring of plant phenotypes. The novel vertical arrangement of this microfluidic device not only allows for normal gravitropic growth of the plants but also, more importantly, makes it convenient to continuously monitor phenotypic changes in plants at the whole organismal level, including seed germination and root and shoot growth (hypocotyls, cotyledons, and leaves), as well as at the cellular level. We also developed a hydrodynamic trapping method to automatically place single seeds into seed holding sites of the device and to avoid potential damage to seeds that might occur during manual loading. We demonstrated general utility of this microfluidic device by showing clear visible phenotypes of the immutans mutant of Arabidopsis, and we also showed changes occurring during plant-pathogen interactions at different developmental stages. Arabidopsis plants grown in the device maintained normal morphological and physiological behaviour, and distinct phenotypic variations consistent with a priori data were observed via high-resolution images taken in real time. Moreover, the timeline for different developmental stages for plants grown in this device was highly comparable to growth using a conventional agar plate method. This prototype plant chip technology is expected to lead to the establishment of a powerful experimental and cost-effective framework for high-throughput and precise plant phenotyping.

  2. Homologous NF-YC2 Subunit from Arabidopsis and Tobacco Is Activated by Photooxidative Stress and Induces Flowering

    PubMed Central

    Hackenberg, Dieter; Keetman, Ulrich; Grimm, Bernhard

    2012-01-01

    The transcription factor NF-Y consists of the three subunits A, B and C, which are encoded in Arabidopsis in large gene families. The multiplicity of the genes implies that NF-Y may act in diverse combinations of each subunit for the transcriptional control. We aimed to assign a function in stress response and plant development to NF-YC subunits by analyzing the expression of NF-Y genes and exploitation of nf-y mutants. Among the subunit family, NF-YC2 showed the strongest inducibility towards oxidative stress, e.g. photodynamic, light, oxidative, heat and drought stress. A tobacco NF-YC homologous gene was found to be inducible by photooxidative stress generated by an accumulation of the tetrapyrrole metabolite, coproporphyrin. Despite the stress induction, an Arabidopsis nf-yc2 mutant and NF-YC2 overexpressors did not show phenotypical differences compared to wild-type seedlings in response to photooxidative stress. This can be explained by the compensatory potential of other members of the NF-YC family. However, NF-YC2 overexpression leads to an early flowering phenotype that is correlated with increased FLOWERING LOCUS T-transcript levels. It is proposed that NF-YC2 functions in floral induction and is a candidate gene among the NF-Y family for the transcriptional activation upon oxidative stress. PMID:22489162

  3. ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS AND TOBACCO PRODUCTS

    EPA Science Inventory

    Previous field and laboratory studies with vascular plants have shown that perchlorate is transported from perchlorate fortified soils and is accumulated in the plant tissues and organs. This paper reports results of initial investigations on the accumulation of perchlorate in t...

  4. DETERMINATION OF PERCHLORATE IN TOBACCO PLANTS AND TOBACCO PRODUCTS

    EPA Science Inventory

    Previous field and laboratory studies with vascular plants have shown that perchlorate is transported from perchlorate fortified soils and is accumulated in the plant tissues and organs. This paper reports results of initial investigations on the accumulation of perchlorate in t...

  5. DETERMINATION OF PERCHLORATE IN TOBACCO PLANTS AND TOBACCO PRODUCTS

    EPA Science Inventory

    Previous field and laboratory studies with vascular plants have shown that perchlorate is transported from perchlorate fortified soils and is accumulated in the plant tissues and organs. This paper reports results of initial investigations on the accumulation of perchlorate in t...

  6. ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS AND TOBACCO PRODUCTS

    EPA Science Inventory

    Previous field and laboratory studies with vascular plants have shown that perchlorate is transported from perchlorate fortified soils and is accumulated in the plant tissues and organs. This paper reports results of initial investigations on the accumulation of perchlorate in t...

  7. Combination of Synthetic Chemistry and Live-Cell Imaging Identified a Rapid Cell Division Inhibitor in Tobacco and Arabidopsis thaliana.

    PubMed

    Nambo, Masakazu; Kurihara, Daisuke; Yamada, Tomomi; Nishiwaki-Ohkawa, Taeko; Kadofusa, Naoya; Kimata, Yusuke; Kuwata, Keiko; Umeda, Masaaki; Ueda, Minako

    2016-11-01

    Cell proliferation is crucial to the growth of multicellular organisms, and thus the proper control of cell division is important to prevent developmental arrest or overgrowth. Nevertheless, tools for controlling cell proliferation are still poor in plant. To develop novel tools, we focused on a specific compound family, triarylmethanes, whose members show various antiproliferative activities in animals. By combining organic chemistry to create novel and diverse compounds containing the triarylmethyl moiety and biological screens based on live-cell imaging of a fluorescently labeled tobacco Bright Yellow-2 (BY-2) culture cell line (Nicotiana tabacum), we isolated (3-furyl)diphenylmethane as a strong but partially reversible inhibitor of plant cell division. We also found that this agent had efficient antiproliferative activity in developing organs of Arabidopsis thaliana without causing secondary defects in cell morphology, and induced rapid cell division arrest independent of the cell cycle stage. Given that (3-furyl)diphenylmethane did not affect the growth of a human cell line (HeLa) and a budding yeast (Saccharomyces cerevisiae), it should act specifically on plants. Taking our results together, we propose that the combination of desired chemical synthesis and detailed biological analysis is an effective tool to create novel drugs, and that (3-furyl)diphenylmethane is a specific antiproliferative agent for plants.

  8. Involvement of a plastid terminal oxidase in plastoquinone oxidation as evidenced by expression of the Arabidopsis thaliana enzyme in tobacco.

    PubMed

    Joët, Thierry; Genty, Bernard; Josse, Eve-Marie; Kuntz, Marcel; Cournac, Laurent; Peltier, Gilles

    2002-08-30

    Chlororespiration has been defined as a respiratory electron transport chain in interaction with photosynthetic electron transport involving both non-photochemical reduction and oxidation of plastoquinones. Different enzymatic activities, including a plastid-encoded NADH dehydrogenase complex, have been reported to be involved in the non-photochemical reduction of plastoquinones. However, the enzyme responsible for plasquinol oxidation has not yet been clearly identified. In order to determine whether the newly discovered plastid oxidase (PTOX) involved in carotenoid biosynthesis acts as a plastoquinol oxidase in higher plant chloroplasts, the Arabidopsis thaliana PTOX gene (At-PTOX) was expressed in tobacco under the control of a strong constitutive promoter. We showed that At-PTOX is functional in tobacco chloroplasts and strongly accelerates the non-photochemical reoxidation of plastoquinols; this effect was inhibited by propyl gallate, a known inhibitor of PTOX. During the dark to light induction phase of photosynthesis at low irradiances, At-PTOX drives significant electron flow to O(2), thus avoiding over-reduction of plastoquinones, when photo- synthetic CO(2) assimilation was not fully induced. We proposed that PTOX, by modulating the redox state of intersystem electron carriers, may participate in the regulation of cyclic electron flow around photosystem I.

  9. 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.

  10. Pathogen resistance of transgenic tobacco plants producing caffeine.

    PubMed

    Kim, Yun-Soo; Sano, Hiroshi

    2008-02-01

    Caffeine (1,3,7-trimethylxanthine) is a typical purine alkaloid, and produced by a variety of plants such as coffee and tea. Its physiological function, however, is not completely understood, but chemical defense against pathogens and herbivores, and allelopathic effects against competing plant species have been proposed. Previously, we constructed transgenic tobacco plants, which produced caffeine up to 5 microg per gram fresh weight of leaves, and showed them to repel caterpillars of tobacco cutworms (Spodoptera litura). In the present study, we found that these transgenic plants constitutively expressed defense-related genes encoding pathogenesis-related (PR)-1a and proteinase inhibitor II under non-stressed conditions. We also found that they were highly resistant against pathogens, tobacco mosaic virus and Pseudomonas syringae. Expression of PR-1a and PR-2 was higher in transgenic plants than in wild-type plants during infection. Exogenously applied caffeine to wild-type tobacco leaves exhibited the similar resistant activity. These results suggested that caffeine stimulated endogenous defense system of host plants through directly or indirectly activating gene expression. This assumption is essentially consistent with the idea of chemical defense, in which caffeine may act as one of signaling molecules to activate defense response. It is thus conceivable that the effect of caffeine is bifunctional; direct interference with pest metabolic pathways, and activation of host defense systems.

  11. AtGIS, a C2H2 zinc-finger transcription factor from Arabidopsis regulates glandular trichome development through GA signaling in tobacco.

    PubMed

    Liu, Yihua; Liu, Dongdong; Hu, Rui; Hua, Changmei; Ali, Imran; Zhang, Aidong; Liu, Bohan; Wu, Minjie; Huang, Linli; Gan, Yinbo

    2017-01-29

    Glandular trichome is specialized multicellular structures that have capability to synthesize and secrete secondary metabolites and protect plants from biotic and abiotic stresses. Our previous results revealed that the C2H2 zinc-finger transcription factors (GIS) acts upstream of GL3/EGL3-GL1-TTG1transcriptional activator complex to regulate trichome initiation through GA signal in Arabidopsis. In the present study, we are reporting that ectopic expression of AtGIS could regulate glandular trichome development through GA signaling in tobacco. X-gluc staining of various organs from transgenic plants showed that AtGIS expressed mainly in the glandular trichomes. Statistical analysis demonstrated that over expression of GIS increased significantly glandular trichome production on the leaf, stem, branch, and sepal in tobacco. After PAC treatment, reduction of glandular trichome production in transgenic plants was more severe with compared to wild type plants. Furthermore, GA treatment could induce expression of AtGIS. More importantly, our results also demonstrated that overexpressed AtGIS significantly affect the main components of trichome exudates, such as significantly increase the content of nicotine, Cembratriene-4, 6-diol. Taken together, these results suggest that ectopic expression of AtGIS regulates glandular trichome development and may play a key role in compounds secretion in tobacco. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Endogenous Methyl Salicylate in Pathogen-Inoculated Tobacco Plants1

    PubMed Central

    Seskar, Mirjana; Shulaev, Vladimir; Raskin, Ilya

    1998-01-01

    The tobacco (Nicotiana tabacum) cultivar Xanthi-nc (genotype NN) produces high levels of salicylic acid (SA) after inoculation with the tobacco mosaic virus (TMV). Gaseous methyl salicylate (MeSA), a major volatile produced in TMV-inoculated tobacco plants, was recently shown to be an airborne defense signal. Using an assay developed to measure the MeSA present in tissue, we have shown that in TMV-inoculated tobacco plants the level of MeSA increases dramatically, paralleling increases in SA. MeSA accumulation was also observed in upper, noninoculated leaves. In TMV-inoculated tobacco shifted from 32 to 24°C, the MeSA concentration increased from nondetectable levels to 2318 ng/g fresh weight 12 h after the temperature shift, but subsequently decreased with the onset of the hypersensitive response. Similar results were observed in plants inoculated with Pseudomonas syringae pathovar phaseolicola, in which MeSA levels were highest just before the hypersensitive response-induced tissue desiccation. Transgenic NahG plants unable to accumulate SA also did not accumulate MeSA after TMV inoculation, and did not show increased resistance to TMV following MeSA treatment. Based on the spatial and temporal kinetics of its accumulation, we conclude that tissue MeSA may play a role similar to that of volatile MeSA in the pathogen-induced defense response.

  13. The Arabidopsis synaptotagmin SYTA regulates the cell-to-cell movement of diverse plant viruses

    PubMed Central

    Uchiyama, Asako; Shimada-Beltran, Harumi; Levy, Amit; Zheng, Judy Y.; Javia, Parth A.; Lazarowitz, Sondra G.

    2014-01-01

    Synaptotagmins are a large gene family in animals that have been extensively characterized due to their role as calcium sensors to regulate synaptic vesicle exocytosis and endocytosis in neurons, and dense core vesicle exocytosis for hormone secretion from neuroendocrine cells. Thought to be exclusive to animals, synaptotagmins have recently been characterized in Arabidopsis thaliana, in which they comprise a five gene family. Using infectivity and leaf-based functional assays, we have shown that Arabidopsis SYTA regulates endocytosis and marks an endosomal vesicle recycling pathway to regulate movement protein-mediated trafficking of the Begomovirus Cabbage leaf curl virus (CaLCuV) and the Tobamovirus Tobacco mosaic virus (TMV) through plasmodesmata (Lewis and Lazarowitz, 2010). To determine whether SYTA has a central role in regulating the cell-to-cell trafficking of a wider range of diverse plant viruses, we extended our studies here to examine the role of SYTA in the cell-to-cell movement of additional plant viruses that employ different modes of movement, namely the Potyvirus Turnip mosaic virus (TuMV), the Caulimovirus Cauliflower mosaic virus (CaMV) and the Tobamovirus Turnip vein clearing virus (TVCV), which in contrast to TMV does efficiently infect Arabidopsis. We found that both TuMV and TVCV systemic infection, and the cell-to-cell trafficking of the their movement proteins, were delayed in the Arabidopsis Col-0 syta-1 knockdown mutant. In contrast, CaMV systemic infection was not inhibited in syta-1. Our studies show that SYTA is a key regulator of plant virus intercellular movement, being necessary for the ability of diverse cell-to-cell movement proteins encoded by Begomoviruses (CaLCuV MP), Tobamoviruses (TVCV and TMV 30K protein) and Potyviruses (TuMV P3N-PIPO) to alter PD and thereby mediate virus cell-to-cell spread. PMID:25414709

  14. Effects of tobacco ethylene receptor mutations on receptor kinase activity, plant growth and stress responses.

    PubMed

    Chen, Tao; Liu, Jun; Lei, Gang; Liu, Yun-Feng; Li, Zhi-Gang; Tao, Jian-Jun; Hao, Yu-Jun; Cao, Yang-Rong; Lin, Qing; Zhang, Wan-Ke; Ma, Biao; Chen, Shou-Yi; Zhang, Jin-Song

    2009-09-01

    Ethylene receptor is the first component of ethylene signaling that regulates plant growth, development and stress responses. Previously, we have demonstrated that tobacco subfamily 2 ethylene receptor NTHK1 had Ser/Thr kinase activity, and overexpression of NTHK1 caused large rosette, reduced ethylene sensitivity, and increased salt sensitivity in transgenic Arabidopsis plants. Here we found that N-box mutation in the NTHK1 kinase domain abolished the kinase activity and led to disruption of NTHK1 roles in conferring reduced ethylene sensitivity and salt sensitive response in transgenic Arabidopsis plants. However, N-box mutation had partial effects on NTHK1 regulation of rosette growth and expression of salt- and ethylene-responsive genes AtNAC2, AtERF1 and AtCor6.6. Mutation of conserved residues in the H box did not affect kinase activity, seedling growth, ethylene sensitivity or salt-induced epinasty in transgenic plants but did influence NTHK1 function in control of specific salt- and ethylene-responsive gene expression. Compared with NTHK1, the tobacco subfamily 1 ethylene receptor NtETR1 had His kinase activity and played a weak role in regulation of rosette growth, triple response and salt response. Mutation of the conserved His residue in the NtETR1 H box eliminated phosphorylation and altered the effect of Ntetr1-1 on reporter gene activity. These results imply that the Ser/Thr kinase activity of NTHK1 is differentially required for various responses, and NTHK1 plays a larger role than NtETR1.

  15. [Tobacco plant parts similarity analysis based on near-infrared spectroscopy and SIMCA algorithm].

    PubMed

    Yu, Chun-Xia; Ma, Xiang; Zhang, Ye-Hui; Li, Jun-Hui; Zhao, Long-Lian; Xu, Li; Wen, Ya-Dong; Wang, Yi; Zhang, Lu-Da

    2011-04-01

    The appearance features of tobacco reflect its inner quality. Many factors, such as different plant parts, variety and maturity, provide standard and foundation for tobacco production processing. According to the different position of tobacco plant parts, tobacco plants leaves can be divided into five parts as tip, upper-middle, middle, lower-middle and priming leaf respectively. Five hundred tobacco leaf samples (100 each for one of five tobacco plant parts) from Yunnan province in 2008 were collected using near infrared spectroscopy, which all belong to tobacco varieties of K326. The similarity analysis of tobacco plant parts was carried out using mathematical model of SIMCA similarity analysis. The conclusion showed that the tobacco plant parts similarity results based on near-infrared spectroscopy corresponded to the relative tobacco plant parts in Yunnan province. The farther two tobacco plant parts were away from each other, the lower the similarity of corresponding parts was. And the similarity results of adjacent tobacco plant parts were different. The study discussed a method of confirming PC numbers and realized the quantitative similarity analysis between classes. It is instructive in replacement or adjustment of tobacco leaf blending and evaluation of tobacco industrial grading.

  16. Specimen block counter-staining for localization of GUS expression in transgenic arabidopsis and tobacco

    NASA Technical Reports Server (NTRS)

    Kim, M. K.; Choi, J-W; Jeon, J-H; Franceschi, V. R.; Davin, L. B.; Lewis, N. G.

    2002-01-01

    A simple counter-staining procedure has been developed for comparative beta-glucuronidase (GUS) expression and anatomical localization in transgenic herbaceous arabidopsis and tobacco. This protocol provides good anatomical visualization for monitoring chimeric gene expression at both the organ and tissue levels. It can be used with different histochemical stains and can be extended to the study of woody species. The specimens are paraffin-embedded, the block is trimmed to reveal internal structure, safranin-O staining solution is briefly applied to the surface of the block, then washed off and, after drying, a drop of immersion oil is placed on the stained surface for subsequent photographic work. This gives tissue counter-staining with good structural preservation without loss of GUS staining product; moreover, sample observation is rapid and efficient compared to existing procedures.

  17. Specimen block counter-staining for localization of GUS expression in transgenic arabidopsis and tobacco

    NASA Technical Reports Server (NTRS)

    Kim, M. K.; Choi, J-W; Jeon, J-H; Franceschi, V. R.; Davin, L. B.; Lewis, N. G.

    2002-01-01

    A simple counter-staining procedure has been developed for comparative beta-glucuronidase (GUS) expression and anatomical localization in transgenic herbaceous arabidopsis and tobacco. This protocol provides good anatomical visualization for monitoring chimeric gene expression at both the organ and tissue levels. It can be used with different histochemical stains and can be extended to the study of woody species. The specimens are paraffin-embedded, the block is trimmed to reveal internal structure, safranin-O staining solution is briefly applied to the surface of the block, then washed off and, after drying, a drop of immersion oil is placed on the stained surface for subsequent photographic work. This gives tissue counter-staining with good structural preservation without loss of GUS staining product; moreover, sample observation is rapid and efficient compared to existing procedures.

  18. Tobacco mosaic virus infection disproportionately impacts phloem associated translatomes in Arabidopsis thaliana and Nicotiana benthamiana.

    PubMed

    Collum, Tamara D; Culver, James N

    2017-10-01

    In this study we use vascular specific promoters and a translating ribosome affinity purification strategy to identify phloem associated translatome responses to infection by tobacco mosaic virus (TMV) in systemic hosts Arabidopsis thaliana ecotype Shahdara and Nicotiana benthamiana. Results demonstrate that in both hosts the number of translatome gene alterations that occurred in response to infection is at least four fold higher in phloem specific translatomes than in non-phloem translatomes. This finding indicates that phloem functions as a key responsive tissue to TMV infection. In addition, host comparisons of translatome alterations reveal both similarities and differences in phloem responses to infection, representing both conserved virus induced phloem alterations involved in promoting infection and virus spread as well as host specific alterations that reflect differences in symptom responses. Combined these results suggest phloem tissues play a disproportion role in the mediation and control of host responses to virus infection. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Ethyl gallate displays elicitor activities in tobacco plants.

    PubMed

    Goupil, Pascale; Benouaret, Razik; Richard, Claire

    2017-09-29

    Alkyl gallates showed elicitor activities on tobacco in both whole plants and cell suspensions. Methyl gallate (MG), ethyl gallate (EG) and propyl gallate (PG) infiltration into tobacco leaves induced hypersensitive reaction-like lesions and topical production of autofluorescent compounds revealed under UV light. When sprayed on tobacco plants at 5 mM, EG promoted upregulation of defence-related genes such as the antimicrobial PR1, -1,3-glucanase PR2, chitinase PR3 and osmotin PR5 target genes. Tobacco BY-2 cells challenged with EG underwent cell death in 48 h, significantly reduced in the presence of the protease inhibitor aprotinin. The three alkyl gallates all caused alkalinisation of the BY-2 extracellular medium, whereas gallic acid did not trigger any pH variation. Using EGTA or LaCl3, we showed that Ca2+ mobilisation occurred in BY-2 cells elicited with EG. Overall, our findings are the first evidence of alkyl gallate elicitor properties with early perception events on plasma membrane, potential hypersensitive reactions and PR-related downstream defence responses in tobacco.

  20. 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

  1. 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.

  2. A Novel Protein Elicitor (PaNie) from Pythium aphanidermatum Induces Multiple Defense Responses in Carrot, Arabidopsis, and Tobacco1

    PubMed Central

    Veit, Stefan; Wörle, Jörg Manfred; Nürnberger, Thorsten; Koch, Wolfgang; Seitz, Hanns Ulrich

    2001-01-01

    A novel protein elicitor (PaNie234) from Pythium aphanidermatum (Edson) Fitzp. was purified, microsequenced, and the corresponding cDNA was cloned. The deduced amino acid sequence contains a putative eukaryotic secretion signal with a proteinase cleavage site. The heterologously expressed elicitor protein without the secretion signal of 21 amino acids (PaNie213) triggered programmed cell death and de novo formation of 4-hydroxybenzoic acid in cultured cells of carrot (Daucus carota). Programmed cell death was determined using the tetrazolium assay and DNA laddering. Infiltration of PaNie213 into the intercellular space of leaves of Arabidopsis (Columbia-0, wild type) resulted in necroses and deposition of callose on the cell walls of spongy parenchyma cells surrounding the necrotic mesophyll cells. Necroses were also formed in tobacco (Nicotiana tabacum cv Wisconsin W38, wild type) and tomato (Lycopersicon esculentum Mill.) but not in maize (Zea mays), oat (Avena sativa), and Tradescantia zebrina (Bosse), indicating that monocotyledonous plants are unable to perceive the signal. The reactions observed after treatment with the purified PaNie213 were identical to responses measured after treatment with a crude elicitor preparation from the culture medium of P. aphanidermatum, described previously. The availability of the pure protein offers the possibility to isolate the corresponding receptor and its connection to downstream signaling-inducing defense reactions. PMID:11706166

  3. Overexpression of an Arabidopsis thaliana ABC transporter confers kanamycin resistance to transgenic plants.

    PubMed

    Mentewab, Ayalew; Stewart, C Neal

    2005-09-01

    Selectable markers of bacterial origin such as the neomycin phosphotransferase type II gene, which can confer kanamycin resistance to transgenic plants, represent an invaluable tool for plant engineering. However, since all currently used antibiotic-resistance genes are of bacterial origin, there have been concerns about horizontal gene transfer from transgenic plants back to bacteria, which may result in antibiotic resistance. Here we characterize a plant gene, Atwbc19, the gene that encodes an Arabidopsis thaliana ATP binding cassette (ABC) transporter and confers antibiotic resistance to transgenic plants. The mechanism of resistance is novel, and the levels of resistance achieved are comparable to those attained through expression of bacterial antibiotic-resistance genes in transgenic tobacco using the CaMV 35S promoter. Because ABC transporters are endogenous to plants, the use of Atwbc19 as a selectable marker in transgenic plants may provide a practical alternative to current bacterial marker genes in terms of the risk for horizontal transfer of resistance genes.

  4. A plant small polypeptide is a novel component of DNA-binding protein phosphatase 1-mediated resistance to plum pox virus in Arabidopsis.

    PubMed

    Castelló, María José; Carrasco, Jose Luis; Navarrete-Gómez, Marisa; Daniel, Jacques; Granot, David; Vera, Pablo

    2011-12-01

    DNA-binding protein phosphatases (DBPs) have been identified as a novel class of plant-specific regulatory factors playing a role in plant-virus interactions. NtDBP1 from tobacco (Nicotiana tabacum) was shown to participate in transcriptional regulation of gene expression in response to virus infection in compatible interactions, and AtDBP1, its closest relative in the model plant Arabidopsis (Arabidopsis thaliana), has recently been found to mediate susceptibility to potyvirus, one of the most speciose taxa of plant viruses. Here, we report on the identification of a novel family of highly conserved small polypeptides that interact with DBP1 proteins both in tobacco and Arabidopsis, which we have designated DBP-interacting protein 2 (DIP2). The interaction of AtDIP2 with AtDBP1 was demonstrated in vivo by bimolecular fluorescence complementation, and AtDIP2 was shown to functionally interfere with AtDBP1 in yeast. Furthermore, reducing AtDIP2 gene expression leads to increased susceptibility to the potyvirus Plum pox virus and to a lesser extent also to Turnip mosaic virus, whereas overexpression results in enhanced resistance. Therefore, we describe a novel family of conserved small polypeptides in plants and identify AtDIP2 as a novel host factor contributing to resistance to potyvirus in Arabidopsis.

  5. A Plant Small Polypeptide Is a Novel Component of DNA-Binding Protein Phosphatase 1-Mediated Resistance to Plum pox virus in Arabidopsis1[C][W

    PubMed Central

    Castelló, María José; Carrasco, Jose Luis; Navarrete-Gómez, Marisa; Daniel, Jacques; Granot, David; Vera, Pablo

    2011-01-01

    DNA-binding protein phosphatases (DBPs) have been identified as a novel class of plant-specific regulatory factors playing a role in plant-virus interactions. NtDBP1 from tobacco (Nicotiana tabacum) was shown to participate in transcriptional regulation of gene expression in response to virus infection in compatible interactions, and AtDBP1, its closest relative in the model plant Arabidopsis (Arabidopsis thaliana), has recently been found to mediate susceptibility to potyvirus, one of the most speciose taxa of plant viruses. Here, we report on the identification of a novel family of highly conserved small polypeptides that interact with DBP1 proteins both in tobacco and Arabidopsis, which we have designated DBP-interacting protein 2 (DIP2). The interaction of AtDIP2 with AtDBP1 was demonstrated in vivo by bimolecular fluorescence complementation, and AtDIP2 was shown to functionally interfere with AtDBP1 in yeast. Furthermore, reducing AtDIP2 gene expression leads to increased susceptibility to the potyvirus Plum pox virus and to a lesser extent also to Turnip mosaic virus, whereas overexpression results in enhanced resistance. Therefore, we describe a novel family of conserved small polypeptides in plants and identify AtDIP2 as a novel host factor contributing to resistance to potyvirus in Arabidopsis. PMID:22021419

  6. Planting molecular functions in an ecological context with Arabidopsis thaliana

    PubMed Central

    Krämer, Ute

    2015-01-01

    The vascular plant Arabidopsis thaliana is a central genetic model and universal reference organism in plant and crop science. The successful integration of different fields of research in the study of A. thaliana has made a large contribution to our molecular understanding of key concepts in biology. The availability and active development of experimental tools and resources, in combination with the accessibility of a wealth of cumulatively acquired knowledge about this plant, support the most advanced systems biology approaches among all land plants. Research in molecular ecology and evolution has also brought the natural history of A. thaliana into the limelight. This article showcases our current knowledge of the natural history of A. thaliana from the perspective of the most closely related plant species, providing an evolutionary framework for interpreting novel findings and for developing new hypotheses based on our knowledge of this plant. DOI: http://dx.doi.org/10.7554/eLife.06100.001 PMID:25807084

  7. Overexpression of Cotton RAV1 Gene in Arabidopsis Confers Transgenic Plants High Salinity and Drought Sensitivity

    PubMed Central

    Li, Xiao-Jie; Li, Mo; Zhou, Ying; Hu, Shan; Hu, Rong; Chen, Yun; Li, Xue-Bao

    2015-01-01

    RAV (related to ABI3/VP1) protein containing an AP2 domain in the N-terminal region and a B3 domain in the C-terminal region, which belongs to AP2 transcription factor family, is unique in higher plants. In this study, a gene (GhRAV1) encoding a RAV protein of 357 amino acids was identified in cotton (Gossypium hirsutum). Transient expression analysis of the eGFP:GhRAV1 fusion genes in tobacco (Nicotiana tabacum) epidermal cells revealed that GhRAV1 protein was localized in the cell nucleus. Quantitative RT-PCR analysis indicated that expression of GhRAV1 in cotton is induced by abscisic acid (ABA), NaCl and polyethylene glycol (PEG). Overexpression of GhRAV1 in Arabidopsis resulted in plant sensitive to ABA, NaCl and PEG. With abscisic acid (ABA) treatment, seed germination and green seedling rates of the GhRAV1 transgenic plants were remarkably lower than those of wild type. In the presence of NaCl, the seed germination and seedling growth of the GhRAV1 transgenic lines were inhibited greater than those of wild type. And chlorophyll content and maximum photochemical efficiency of the transgenic plants were significantly lower than those of wild type. Under drought stress, the GhRAV1 transgenic plants displayed more severe wilting than wild type. Furthermore, expressions of the stress-related genes were altered in the GhRAV1 transgenic Arabidopsis plants under high salinity and drought stresses. Collectively, our data suggested that GhRAV1 may be involved in response to high salinity and drought stresses through regulating expressions of the stress-related genes during cotton development. PMID:25710493

  8. Overexpression of Two PsnAP1 Genes from Populus simonii × P. nigra Causes Early Flowering in Transgenic Tobacco and Arabidopsis

    PubMed Central

    Zheng, Tangchun; Li, Shuang; Zang, Lina; Dai, Lijuan; Yang, Chuanping; Qu, Guan-Zheng

    2014-01-01

    In Arabidopsis, AP1 is a floral meristem identity gene and plays an important role in floral organ development. In this study, PsnAP1-1 and PsnAP1-2 were isolated from the male reproductive buds of poplar (Populus simonii × P. nigra), which are the orthologs of AP1 in Arabidopsis, by sequence analysis. Northern blot and qRT-PCR analysis showed that PsnAP1-1 and PsnAP1-2 exhibited high expression level in early inflorescence development of poplar. Subcellular localization showed the PsnAP1-1 and PsnAP1-2 proteins are localized in the nucleus. Overexpression of PsnAP1-1 and PsnAP1-2 in tobacco under the control of a CaMV 35S promoter significantly enhanced early flowering. These transgenic plants also showed much earlier stem initiation and higher rates of photosynthesis than did wild-type tobacco. qRT-PCR analysis further indicated that overexpression of PsnAP1-1 and PsnAP1-2 resulted in up-regulation of genes related to flowering, such as NtMADS4, NtMADS5 and NtMADS11. Overexpression of PsnAP1-1 and PsnAP1-2 in Arabidopsis also induced early flowering, but did not complement the ap1-10 floral morphology to any noticeable extent. This study indicates that PsnAP1-1 and PsnAP1-2 play a role in floral transition of poplar. PMID:25360739

  9. Localization of arginine decarboxylase in tobacco plants.

    PubMed

    Bortolotti, Cristina; Cordeiro, Alexandra; Alcázar, Rubén; Borrell, Antoni; Culiañez-Macià, Francisco A.; Tiburcio, Antonio F.; Altabella, Teresa

    2004-01-01

    The lack of knowledge about the tissue and subcellular distribution of polyamines (PAs) and the enzymes involved in their metabolism remains one of the main obstacles in our understanding of the biological role of PAs in plants. Arginine decarboxylase (ADC; EC 4.1.1.9) is a key enzyme in polyamine biosynthesis in plants. We have characterized a cDNA coding for ADC from Nicotiana tabacum L. cv. Petit Havana SR1. The deduced ADC polypeptide had 721 amino acids and a molecular mass of 77 kDa. The ADC cDNA was overexpressed in Escherichia coli, and the ADC fusion protein obtained was used to produce polyclonal antibodies. Using immunological methods, we demonstrate the presence of the ADC protein in all plant organs analysed: flowers, seeds, stems, leaves and roots. Moreover, depending on the tissue, the protein is localized in two different subcellular compartments, the nucleus and the chloroplast. In photosynthetic tissues, ADC is located mainly in chloroplasts, whereas in non-photosynthetic tissues the protein appears to be located in nuclei. The different compartmentation of ADC may be related to distinct functions of the protein in different cell types.

  10. A trio of viral proteins tunes aphid-plant interactions in Arabidopsis thaliana.

    PubMed

    Westwood, Jack H; Groen, Simon C; Du, Zhiyou; Murphy, Alex M; Anggoro, Damar Tri; Tungadi, Trisna; Luang-In, Vijitra; Lewsey, Mathew G; Rossiter, John T; Powell, Glen; Smith, Alison G; Carr, John P

    2013-01-01

    Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: 'peach-potato aphid', 'green peach aphid'). Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between the effects of Fny-CMV on this plant and those seen previously in tobacco

  11. A Trio of Viral Proteins Tunes Aphid-Plant Interactions in Arabidopsis thaliana

    PubMed Central

    Du, Zhiyou; Murphy, Alex M.; Anggoro, Damar Tri; Tungadi, Trisna; Luang-In, Vijitra; Lewsey, Mathew G.; Rossiter, John T.; Powell, Glen; Smith, Alison G.; Carr, John P.

    2013-01-01

    Background Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: ‘peach-potato aphid’, ‘green peach aphid’). Methodology/Principal Findings Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Conclusions/Significance Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between

  12. Transgenic tobacco overexpressing Brassica juncea HMG-CoA synthase 1 shows increased plant growth, pod size and seed yield.

    PubMed

    Liao, Pan; Wang, Hui; Wang, Mingfu; Hsiao, An-Shan; Bach, Thomas J; Chye, Mee-Len

    2014-01-01

    Seeds are very important not only in the life cycle of the plant but they represent food sources for man and animals. We report herein a mutant of 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMGS), the second enzyme in the mevalonate (MVA) pathway that can improve seed yield when overexpressed in a phylogenetically distant species. In Brassica juncea, the characterisation of four isogenes encoding HMGS has been previously reported. Enzyme kinetics on recombinant wild-type (wt) and mutant BjHMGS1 had revealed that S359A displayed a 10-fold higher enzyme activity. The overexpression of wt and mutant (S359A) BjHMGS1 in Arabidopsis had up-regulated several genes in sterol biosynthesis, increasing sterol content. To quickly assess the effects of BjHMGS1 overexpression in a phylogenetically more distant species beyond the Brassicaceae, wt and mutant (S359A) BjHMGS1 were expressed in tobacco (Nicotiana tabacum L. cv. Xanthi) of the family Solanaceae. New observations on tobacco OEs not previously reported for Arabidopsis OEs included: (i) phenotypic changes in enhanced plant growth, pod size and seed yield (more significant in OE-S359A than OE-wtBjHMGS1) in comparison to vector-transformed tobacco, (ii) higher NtSQS expression and sterol content in OE-S359A than OE-wtBjHMGS1 corresponding to greater increase in growth and seed yield, and (iii) induction of NtIPPI2 and NtGGPPS2 and downregulation of NtIPPI1, NtGGPPS1, NtGGPPS3 and NtGGPPS4. Resembling Arabidopsis HMGS-OEs, tobacco HMGS-OEs displayed an enhanced expression of NtHMGR1, NtSMT1-2, NtSMT2-1, NtSMT2-2 and NtCYP85A1. Overall, increased growth, pod size and seed yield in tobacco HMGS-OEs were attributed to the up-regulation of native NtHMGR1, NtIPPI2, NtSQS, NtSMT1-2, NtSMT2-1, NtSMT2-2 and NtCYP85A1. Hence, S359A has potential in agriculture not only in improving phytosterol content but also seed yield, which may be desirable in food crops. This work further demonstrates HMGS function in plant reproduction

  13. Transgenic Tobacco Overexpressing Brassica juncea HMG-CoA Synthase 1 Shows Increased Plant Growth, Pod Size and Seed Yield

    PubMed Central

    Liao, Pan; Wang, Hui; Wang, Mingfu; Hsiao, An-Shan; Bach, Thomas J.; Chye, Mee-Len

    2014-01-01

    Seeds are very important not only in the life cycle of the plant but they represent food sources for man and animals. We report herein a mutant of 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMGS), the second enzyme in the mevalonate (MVA) pathway that can improve seed yield when overexpressed in a phylogenetically distant species. In Brassica juncea, the characterisation of four isogenes encoding HMGS has been previously reported. Enzyme kinetics on recombinant wild-type (wt) and mutant BjHMGS1 had revealed that S359A displayed a 10-fold higher enzyme activity. The overexpression of wt and mutant (S359A) BjHMGS1 in Arabidopsis had up-regulated several genes in sterol biosynthesis, increasing sterol content. To quickly assess the effects of BjHMGS1 overexpression in a phylogenetically more distant species beyond the Brassicaceae, wt and mutant (S359A) BjHMGS1 were expressed in tobacco (Nicotiana tabacum L. cv. Xanthi) of the family Solanaceae. New observations on tobacco OEs not previously reported for Arabidopsis OEs included: (i) phenotypic changes in enhanced plant growth, pod size and seed yield (more significant in OE-S359A than OE-wtBjHMGS1) in comparison to vector-transformed tobacco, (ii) higher NtSQS expression and sterol content in OE-S359A than OE-wtBjHMGS1 corresponding to greater increase in growth and seed yield, and (iii) induction of NtIPPI2 and NtGGPPS2 and downregulation of NtIPPI1, NtGGPPS1, NtGGPPS3 and NtGGPPS4. Resembling Arabidopsis HMGS-OEs, tobacco HMGS-OEs displayed an enhanced expression of NtHMGR1, NtSMT1-2, NtSMT2-1, NtSMT2-2 and NtCYP85A1. Overall, increased growth, pod size and seed yield in tobacco HMGS-OEs were attributed to the up-regulation of native NtHMGR1, NtIPPI2, NtSQS, NtSMT1-2, NtSMT2-1, NtSMT2-2 and NtCYP85A1. Hence, S359A has potential in agriculture not only in improving phytosterol content but also seed yield, which may be desirable in food crops. This work further demonstrates HMGS function in plant reproduction

  14. Mining the plant-herbivore interface with a leafmining Drosophila of Arabidopsis

    PubMed Central

    Whiteman, Noah K.; Groen, Simon C.; Chevasco, Daniela; Bear, Ashley; Beckwith, Noor; Gregory, T. Ryan; Denoux, Carine; Mammarella, Nicole; Ausubel, Frederick M.; Pierce, Naomi E.

    2010-01-01

    Experimental infections of Arabidopsis thaliana (Arabidopsis) with genomically characterized plant pathogens such as Pseudomonas syringae have facilitated dissection of canonical eukaryotic defense pathways and parasite virulence factors. Plants are also attacked by herbivorous insects, and the development of an ecologically relevant genetic model herbivore that feeds on Arabidopsis will enable the parallel dissection of host defense and reciprocal resistance pathways such as those involved in xenobiotic metabolism. An ideal candidate is Scaptomyza flava, a drosophilid fly whose leafmining larvae are true herbivores that can be found in nature feeding on Arabidopsis and other crucifers. Here we describe the eukaryotic life cycle of S. flava on Arabidopsis, and use multiple approaches to characterize the response of Arabidopsis to S. flava attack. Oviposition choice tests and growth performance assays on different Arabidopsis ecotypes, defense-related mutants, and hormone and chitin-treated plants revealed significant differences in host preference and variation in larval performance across Arabidopsis accessions. The jasmonate (JA) and glucosinolate pathways in Arabidopsis are important in mediating quantitative resistance against S. flava, and priming with JA or chitin resulted in increased resistance. Expression of xenobiotic detoxification genes was reduced in S. flava larvae reared on Arabidopsis JA signaling mutants, and increased in plants pre-treated with chitin. These results and future research directions are discussed in the context of developing a genetic model system to analyze insect/plant interactions. PMID:21073583

  15. Specific requirement for translation initiation factor 4E or its isoform drives plant host susceptibility to Tobacco etch virus

    PubMed Central

    2014-01-01

    Background In plants, eIF4E translation initiation factors and their eIFiso4E isoforms are essential susceptibility factors for many RNA viruses, including potyviruses. Mutations altering these factors are a major source of resistance to the viruses. The eIF4E allelic series is associated with specific resistance spectra in crops such as Capsicum annum. Genetic evidence shows that potyviruses have a specific requirement for a given 4E isoform that depends on the host plant. For example, Tobacco etch virus (TEV) uses eIF4E1 to infect Capsicum annuum but uses eIFiso4E to infect Arabidopsis thaliana. Here, we investigated how TEV exploits different translation initiation factor isoforms to infect these two plant species. Results A complementation system was set up in Arabidopsis to test the restoration of systemic infection by TEV. Using this system, Arabidopsis susceptibility to TEV was complemented with a susceptible pepper eIF4E1 allele but not with a resistant allele. Therefore, in Arabidopsis, TEV can use the pepper eIF4E1 instead of the endogenous eIFiso4E isoform so is able to switch between translation initiation factor 4E isoform to infect the same host. Moreover, we show that overexpressing the pepper eIF4E1 alleles is sufficient to make Arabidopsis susceptible to an otherwise incompatible TEV strain. Lastly, we show that the resistant eIF4E1 allele is similarly overcome by a resistance-breaking TEV strain as in pepper, confirming that this Arabidopsis TEV-susceptibility complementation system is allele-specific. Conclusion We report here a complementation system in Arabidopsis that makes it possible to assess the role of pepper pvr2-eIF4E alleles in susceptibility to TEV. Heterologous complementation experiments showed that the idiosyncratic properties of the 4E and iso4E proteins create a major checkpoint for viral infection of different hosts. This system could be used to screen natural or induced eIF4E alleles to find and study alleles of interest for

  16. [Nitrogen uptake and allocation characteristics of flue-cured tobacco in Nanxiong tobacco-planting area of Guangdong Province].

    PubMed

    Yang, Zhi-Xiao; Liu, Hua-Bing; Ke, You-Song; Wu, Wen-Bin; Zhang, Xiao-Quan; Qiu, Miao-Wen; Zhao, Wei-Cai; Yang, Tie-Zhao

    2011-06-01

    By the method of field in situ culture and 15N isotopic tracer technique, and taking flue-cured tobacco (Nicotiana tobacum) cultivar K326 as test material, a field experiment was conducted in the Nanxiong tobacco-planting area of Guangdong Province to study the characteristics of soil nitrogen (N) mineralization, the patterns of N accumulation and allocation in tobacco plants, and the allocation of plant-absorbed fertilizer N applied in current growth season. In the study area, the amount of soil mineralized N increased with tobacco growth, peaked at 75 days after transplanting, and decreased thereafter. The soil mineralized N at each tobacco growth stage was significantly higher in the control than in the N fertilization treatment. The N accumulation in tobacco plant organs was in the order of leaf > stalk > root. Tobacco plants mainly absorbed fertilizer N at rosette stage and topping stage, and mainly absorbed soil N at mature stage. The absorbed N in tobacco whole growth period was mainly derived from soil N, and the absorbed soil N and its proportion to the total absorbed N increased evidently with extending growth stage and ascending leaf position. The fertilizer N use efficiency per plant and the residual rate and loss rate of applied fertilizer N were 30. 8%, 32. 3% , and 36. 9% , respectively. In the study area, soil N mineralization rate was relatively high, and soil N had greater effects on the quality of upper tobacco leaves. Under the application rate of 150 kg N x hm(-2), the residual amount and loss amount of applied fertilizer N were relatively high.

  17. Root-Specific Reduction of Cytokinin Causes Enhanced Root Growth, Drought Tolerance, and Leaf Mineral Enrichment in Arabidopsis and Tobacco[C][W][OA

    PubMed Central

    Werner, Tomáš; Nehnevajova, Erika; Köllmer, Ireen; Novák, Ondřej; Strnad, Miroslav; Krämer, Ute; Schmülling, Thomas

    2010-01-01

    Optimizing root system architecture can overcome yield limitations in crop plants caused by water or nutrient shortages. Classic breeding approaches are difficult because the trait is governed by many genes and is difficult to score. We generated transgenic Arabidopsis thaliana and tobacco (Nicotiana tabacum) plants with enhanced root-specific degradation of the hormone cytokinin, a negative regulator of root growth. These transgenic plants form a larger root system, whereas growth and development of the shoot are similar. Elongation of the primary root, root branching, and root biomass formation were increased by up to 60% in transgenic lines, increasing the root-to-shoot ratio. We thus demonstrated that a single dominant gene could regulate a complex trait, root growth. Moreover, we showed that cytokinin regulates root growth in a largely organ-autonomous fashion that is consistent with its dual role as a hormone with both paracrine and long-distance activities. Transgenic plants had a higher survival rate after severe drought treatment. The accumulation of several elements, including S, P, Mn, Mg, Zn, as well as Cd from a contaminated soil, was significantly increased in shoots. Under conditions of sulfur or magnesium deficiency, leaf chlorophyll content was less affected in transgenic plants, demonstrating the physiological relevance of shoot element accumulation. Our approach might contribute to improve drought tolerance, nutrient efficiency, and nutrient content of crop plants. PMID:21148816

  18. Loss of Inositol Phosphorylceramide Sphingolipid Mannosylation Induces Plant Immune Responses and Reduces Cellulose Content in Arabidopsis.

    PubMed

    Fang, Lin; Ishikawa, Toshiki; Rennie, Emilie A; Murawska, Gosia M; Lao, Jeemeng; Yan, Jingwei; Tsai, Alex Yi-Lin; Baidoo, Edward E K; Xu, Jun; Keasling, Jay D; Demura, Taku; Kawai-Yamada, Maki; Scheller, Henrik V; Mortimer, Jenny C

    2016-12-01

    Glycosylinositol phosphorylceramides (GIPCs) are a class of glycosylated sphingolipids found in plants, fungi, and protozoa. These lipids are abundant in the plant plasma membrane, forming ∼25% of total plasma membrane lipids. Little is known about the function of the glycosylated headgroup, but two recent studies have indicated that they play a key role in plant signaling and defense. Here, we show that a member of glycosyltransferase family 64, previously named ECTOPICALLY PARTING CELLS1, is likely a Golgi-localized GIPC-specific mannosyl-transferase, which we renamed GIPC MANNOSYL-TRANSFERASE1 (GMT1). Sphingolipid analysis revealed that the Arabidopsis thaliana gmt1 mutant almost completely lacks mannose-carrying GIPCs. Heterologous expression of GMT1 in Saccharomyces cerevisiae and tobacco (Nicotiana tabacum) cv Bright Yellow 2 resulted in the production of non-native mannosylated GIPCs. gmt1 displays a severe dwarfed phenotype and a constitutive hypersensitive response characterized by elevated salicylic acid and hydrogen peroxide levels, similar to that we previously reported for the Golgi-localized, GIPC-specific, GDP-Man transporter GONST1 (Mortimer et al., 2013). Unexpectedly, we show that gmt1 cell walls have a reduction in cellulose content, although other matrix polysaccharides are unchanged. © 2016 American Society of Plant Biologists. All rights reserved.

  19. Cytokinin Biosynthesis in Cultured Rootless Tobacco Plants 1

    PubMed Central

    Chen, Chong-maw; Petschow, Bryon

    1978-01-01

    Biosynthesis of cytokinin in shoots was examined by growing rootless tobacco (Nicotiana tabacum) plants in vitro. The rootless plants were originated by culturing tobacco callus on a high cytokinin-low auxin medium to induce the formation of plantlets which were then grown on medium without exogenous cytokinin and auxin. The rootless plants supplied with [14C]adenine synthesized ethanol-ethyl acetate-water-soluble radioactive components, portions of which had the same chromatographic and electrophoretic mobilities as N6-(Δ2-isopentenyl)adenine, N6-(Δ2-isopentenyl)adenosine, 6-(4-hydroxy-3-methyl-2-butenylamino)purine and 6-(4-hydroxy-3-methyl-2-butenylamino)-9-β-d-ribofuranosylpurine. The total amount of these four major cytokinins was estimated to be present at a concentration of 14 to 23 nanomoles per kilogram of rootless plant. These data indicate that adenine serves as a precursor of the purine moiety of cytokinin molecules and that the cytokinin biosynthetic sites are also located in the shoot in addition to the presumed root sites. ImagesFig. 1 PMID:16660626

  20. Whole genome duplications in plants: an overview from Arabidopsis.

    PubMed

    del Pozo, Juan Carlos; Ramirez-Parra, Elena

    2015-12-01

    Polyploidy is a common event in plants that involves the acquisition of more than two complete sets of chromosomes. Allopolyploidy originates from interspecies hybrids while autopolyploidy originates from intraspecies whole genome duplication (WGD) events. In spite of inconveniences derived from chromosomic rearrangement during polyploidization, natural plant polyploids species often exhibit improved growth vigour and adaptation to adverse environments, conferring evolutionary advantages. These advantages have also been incorporated into crop breeding programmes. Many tetraploid crops show increased stress tolerance, although the molecular mechanisms underlying these different adaptation abilities are poorly known. Understanding the physiological, cellular, and molecular mechanisms coupled to WGD, in both allo- and autopolyploidy, is a major challenge. Over the last few years, several studies, many of them in Arabidopsis, are shedding light on the basis of genetic, genomic, and epigenomic changes linked to WGD. In this review we summarize and discuss the latest advances made in Arabidopsis polyploidy, but also in other agronomic plant species. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. Composition of hydroponic medium affects thorium uptake by tobacco plants.

    PubMed

    Soudek, Petr; Kufner, Daniel; Petrová, Sárka; Mihaljevič, Martin; Vaněk, Tomáš

    2013-08-01

    The ability of thorium uptake as well as responses to heavy metal stress were tested in tobacco cultivar La Burley 21. Thorium was accumulated preferentially in the root system. The presence of citric, tartaric and oxalic acids in hydroponic medium increased thorium accumulation in all plant organs. On the other hand, the addition of diamines and polyamines, the important antioxidants in plants, resulted in decrease of thorium accumulation, especially in the root system. Negative correlation was found between putrescine concentration and thorium accumulation. Nevertheless, the most important factor influencing the accumulation of thorium was the absence of phosphate ions in a hydroponic medium that caused more than 10-fold increase of thorium uptake in all plant parts. Accumulation and distribution of thorium was followed in six cultivars and 14 selected transformants. Cultivar La Barley 21 represented an average between the tested genotypes, having a very good distribution ratio between roots, stems and leaves.

  2. System identification of the Arabidopsis plant circadian system

    NASA Astrophysics Data System (ADS)

    Foo, Mathias; Somers, David E.; Kim, Pan-Jun

    2015-02-01

    The circadian system generates an endogenous oscillatory rhythm that governs the daily activities of organisms in nature. It offers adaptive advantages to organisms through a coordination of their biological functions with the optimal time of day. In this paper, a model of the circadian system in the plant Arabidopsis (species thaliana) is built by using system identification techniques. Prior knowledge about the physical interactions of the genes and the proteins in the plant circadian system is incorporated in the model building exercise. The model is built by using primarily experimentally-verified direct interactions between the genes and the proteins with the available data on mRNA and protein abundances from the circadian system. Our analysis reveals a great performance of the model in predicting the dynamics of the plant circadian system through the effect of diverse internal and external perturbations (gene knockouts and day-length changes). Furthermore, we found that the circadian oscillatory rhythm is robust and does not vary much with the biochemical parameters except those of a light-sensitive protein P and a transcription factor TOC1. In other words, the circadian rhythmic profile is largely a consequence of the network's architecture rather than its particular parameters. Our work suggests that the current experimental knowledge of the gene-to-protein interactions in the plant Arabidopsis, without considering any additional hypothetical interactions, seems to suffice for system-level modeling of the circadian system of this plant and to present an exemplary platform for the control of network dynamics in complex living organisms.

  3. Loss of Inositol Phosphorylceramide Sphingolipid Mannosylation Induces Plant Immune Responses and Reduces Cellulose Content in Arabidopsis

    SciTech Connect

    Fang, Lin; Ishikawa, Toshiki; Rennie, Emilie A.; Murawska, Gosia M.; Lao, Jeemeng; Yan, Jingwei; Tsai, Alex Yi-Lin; Baidoo, Edward E. K.; Xu, Jun; Keasling, Jay D.; Demura, Taku; Kawai-Yamada, Maki; Scheller, Henrik V.; Mortimer, Jenny C.

    2016-11-28

    Glycosylinositol phosphorylceramides (GIPCs) are a class of glycosylated sphingolipids found in plants, fungi, and protozoa. These lipids are abundant in the plant plasma membrane, forming ~25% of total plasma membrane lipids. Little is known about the function of the glycosylated headgroup, but two recent studies have indicated that they play a key role in plant signaling and defense. Here, we show that a member of glycosyltransferase family 64, previously named ECTOPICALLY PARTING CELLS1, is likely a Golgi-localized GIPC-specific mannosyl-transferase, which we renamed GIPC MANNOSYL-TRANSFERASE1 (GMT1). Sphingolipid analysis revealed that the Arabidopsis thaliana gmt1 mutant almost completely lacks mannose-carrying GIPCs. Heterologous expression of GMT1 in Saccharomyces cerevisiae and tobacco (Nicotiana tabacum) cv Bright Yellow 2 resulted in the production of non-native mannosylated GIPCs. gmt1 displays a severe dwarfed phenotype and a constitutive hypersensitive response characterized by elevated salicylic acid and hydrogen peroxide levels, similar to that we previously reported for the Golgi-localized, GIPC-specific, GDP-Man transporter GONST1 (Mortimer et al., 2013). Unexpectedly, we show that gmt1 cell walls have a reduction in cellulose content, although other matrix polysaccharides are unchanged.

  4. Loss of Inositol Phosphorylceramide Sphingolipid Mannosylation Induces Plant Immune Responses and Reduces Cellulose Content in Arabidopsis

    DOE PAGES

    Fang, Lin; Ishikawa, Toshiki; Rennie, Emilie A.; ...

    2016-11-28

    Glycosylinositol phosphorylceramides (GIPCs) are a class of glycosylated sphingolipids found in plants, fungi, and protozoa. These lipids are abundant in the plant plasma membrane, forming ~25% of total plasma membrane lipids. Little is known about the function of the glycosylated headgroup, but two recent studies have indicated that they play a key role in plant signaling and defense. Here, we show that a member of glycosyltransferase family 64, previously named ECTOPICALLY PARTING CELLS1, is likely a Golgi-localized GIPC-specific mannosyl-transferase, which we renamed GIPC MANNOSYL-TRANSFERASE1 (GMT1). Sphingolipid analysis revealed that the Arabidopsis thaliana gmt1 mutant almost completely lacks mannose-carrying GIPCs. Heterologousmore » expression of GMT1 in Saccharomyces cerevisiae and tobacco (Nicotiana tabacum) cv Bright Yellow 2 resulted in the production of non-native mannosylated GIPCs. gmt1 displays a severe dwarfed phenotype and a constitutive hypersensitive response characterized by elevated salicylic acid and hydrogen peroxide levels, similar to that we previously reported for the Golgi-localized, GIPC-specific, GDP-Man transporter GONST1 (Mortimer et al., 2013). Unexpectedly, we show that gmt1 cell walls have a reduction in cellulose content, although other matrix polysaccharides are unchanged.« less

  5. An antibody produced in tobacco expressing a hybrid β-1,4-galactosyltransferase is essentially devoid of plant carbohydrate epitopes

    PubMed Central

    Bakker, Hans; Rouwendal, Gerard J. A.; Karnoup, Anton S.; Florack, Dion E. A.; Stoopen, Geert M.; Helsper, Johannes P. F. G.; van Ree, Ronald; van Die, Irma; Bosch, Dirk

    2006-01-01

    N-glycosylation of a mAb may have a major impact on its therapeutic merits. Here, we demonstrate that expression of a hybrid enzyme (called xylGalT), consisting of the N-terminal domain of Arabidopsis thaliana xylosyltransferase and the catalytic domain of human β-1,4-galactosyltransferase I (GalT), in tobacco causes a sharp reduction of N-glycans with potentially immunogenic core-bound xylose (Xyl) and fucose (Fuc) residues as shown by Western blot and MALDI-TOF MS analysis. A radioallergosorbent test inhibition assay with proteins purified from leaves of WT and these transgenic tobacco plants using sera from allergic patients suggests a significant reduction of potential immunogenicity of xylGalT proteins. A mAb purified from leaves of plants expressing xylGalT displayed an N-glycan profile that featured high levels of galactose, undetectable xylose, and a trace of fucose. Hence, a transgenic plant expressing the hybrid GalT might yield more effective and safer monoclonals for therapeutic purposes than WT plants and even transgenic plants expressing the unchanged GalT. PMID:16675551

  6. Enhanced Cd2+ -selective root-tonoplast-transport in tobaccos expressing Arabidopsis cation exchangers.

    PubMed

    Koren'kov, V; Park, S; Cheng, N-H; Sreevidya, C; Lachmansingh, J; Morris, J; Hirschi, K; Wagner, G J

    2007-01-01

    Several Arabidopsis CAtion eXchangers (CAXs) encode tonoplast-localized transporters that appear to be major contributors to vacuolar accumulation/sequestration of cadmium (Cd(2+)), an undesirable pollutant ion that occurs in man largely as a result of dietary consumption of aerial tissues of food plants. But, ion-selectivity of individual CAX transporter types remains largely unknown. Here, we transformed Nicotiana tabacum with several CAX genes driven by the Cauliflower Mosaic Virus (CaMV) 35S promoter and monitored divalent cation transport in root-tonoplast vesicles from these plants in order to select particular CAX genes directing high Cd(2+) antiporter activity in root tonoplast. Comparison of seven different CAX genes indicated that all transported Cd(2+), Ca(2+), Zn(2+), and Mn(2+) to varying degrees, but that CAX4 and CAX2 had high Cd(2+) transport and selectivity in tonoplast vesicles. CAX4 driven by the CaMV 35S and FS3 [figwort mosaic virus (FMV)] promoters increased the magnitude and initial rate of Cd(2+)/H(+) exchange in root-tonoplast vesicles. Ion selectivity of transport in root-tonoplast vesicles isolated from FS3::CAX4-expressing plant lines having a range of gene expression was Cd(2+)>Zn(2+)>Ca(2+)>Mn(2+) and the ratios of maximal Cd(2+) (and Zn(2+)) versus maximal Ca(2+) and Mn(2+) transport were correlated with the levels of CAX4 expression. Root Cd accumulation in high CAX4 and CAX2 expressing lines was increased in seedlings grown with 0.02 muM Cd. These observations are consistent with a model in which expression of an Arabidopsis-gene-encoded, Cd(2+)-efficient antiporter in host plant roots results in greater root vacuole Cd(2+) transport activity, increased root Cd accumulation, and a shift in overall root tonoplast ion transport selectivity towards higher Cd(2+) selectivity. Results support a model in which certain CAX antiporters are somewhat more selective for particular divalent cations.

  7. A phospholipid uptake system in the model plant Arabidopsis thaliana.

    PubMed

    Poulsen, Lisbeth R; López-Marqués, Rosa L; Pedas, Pai R; McDowell, Stephen C; Brown, Elizabeth; Kunze, Reinhard; Harper, Jeffrey F; Pomorski, Thomas G; Palmgren, Michael

    2015-07-27

    Plants use solar energy to produce lipids directly from inorganic elements and are not thought to require molecular systems for lipid uptake from the environment. Here we show that Arabidopsis thaliana Aminophospholipid ATPase10 (ALA10) is a P4-type ATPase flippase that internalizes exogenous phospholipids across the plasma membrane, after which they are rapidly metabolized. ALA10 expression and phospholipid uptake are high in the epidermal cells of the root tip and in guard cells, the latter of which regulate the size of stomatal apertures to modulate gas exchange. ALA10-knockout mutants exhibit reduced phospholipid uptake at the root tips and guard cells and are affected in growth and transpiration. The presence of a phospholipid uptake system in plants is surprising. Our results suggest that one possible physiological role of this system is to internalize lysophosphatidylcholine, a signalling lipid involved in root development and stomatal control.

  8. Peroxidase-induced wilting in transgenic tobacco plants

    SciTech Connect

    Lagrimini, L.M.; Bradford, S. ); Rothstein, S. )

    1990-01-01

    Peroxidases are a family of isoenzymes found in all higher plants. However, little is known concerning their role in growth, development or response to stress. Plant peroxidases are heme-containing monomeric glycoproteins that utilize either H{sub 2}O{sub 2} or O{sub 2} to oxidize a wide variety of molecules. To obtain more information on possible in planta functions of peroxidases, the authors have used a cDNA clone for the primary isoenzyme form of peroxidase to synthesize high levels of this enzyme in transgenic plants. They were able to obtain Nicotiana tabacum and N. sylvestris transformed plants with peroxidase activity that is 10-fold higher than in wild-type plants by introducing a chimeric gene composed of the cauliflower mosaic virus 35S promoter and the tobacco anionic peroxidase cDNA. The elevated peroxidase activity was a result of increased levels of two anionic peroxidases in N. tabacum, which apparently differ in post-translational modification. Transformed plants of both species have the unique phenotype of chronic severe wilting through loss of turgor in leaves, which was initiated a the time of flowering. The peroxidase-induced wilting was shown not to be an effect of diminished water uptake through the roots, decreased conductance of water through the xylem, or increased water loss through the leaf surface of stomata. Possible explanations for the loss of turgor, and the significance of these types of experiments in studying isoenzyme families, are discussed.

  9. Antibody degradation in tobacco plants: a predominantly apoplastic process

    PubMed Central

    2011-01-01

    Background Interest in using plants for production of recombinant proteins such as monoclonal antibodies is growing, but proteolytic degradation, leading to a loss of functionality and complications in downstream purification, is still a serious problem. Results In this study, we investigated the dynamics of the assembly and breakdown of a human IgG1κ antibody expressed in plants. Initial studies in a human IgG transgenic plant line suggested that IgG fragments were present prior to extraction. Indeed, when the proteolytic activity of non-transgenic Nicotiana tabacum leaf extracts was tested against a human IgG1 substrate, little activity was detectable in extraction buffers with pH > 5. Significant degradation was only observed when the plant extract was buffered below pH 5, but this proteolysis could be abrogated by addition of protease inhibitors. Pulse-chase analysis of IgG MAb transgenic plants also demonstrated that IgG assembly intermediates are present intracellularly and are not secreted, and indicates that the majority of proteolytic degradation occurs following secretion into the apoplastic space. Conclusions The results provide evidence that proteolytic fragments derived from antibodies of the IgG subtype expressed in tobacco plants do not accumulate within the cell, and are instead likely to occur in the apoplastic space. Furthermore, any proteolytic activity due to the release of proteases from subcellular compartments during tissue disruption and extraction is not a major consideration under most commonly used extraction conditions. PMID:22208820

  10. Altered phenotypes in plants transformed with chimeric tobacco peroxidase genes

    SciTech Connect

    Lagrimini, L.M.

    1990-01-01

    Peroxidases have been implicated in a variety of secondary metabolic reactions including lignification, cross-linking of cell wall polysaccharides, oxidation of indole-3-acetic acid, regulation of cell elongation, wound-healing, phenol oxidation, and pathogen defense. However, due to the many different isoenzymes and even more potential substrates, it has proven difficult to verify actual physiological roles for peroxidase. We are studying the molecular biology of the tobacco peroxidase genes, and have utilized genetic engineering techniques to produce transgenic plants which differ only in their expression of an individual peroxidase isoenzyme. Many of the in planta functions for any individual isoenzyme may be predicted through the morphological and physiological analysis of transformed plants.

  11. Altered phenotypes in plants transformed with chimeric tobacco peroxidase genes

    SciTech Connect

    Lagrimini, L.M.

    1990-12-31

    Peroxidases have been implicated in a variety of secondary metabolic reactions including lignification, cross-linking of cell wall polysaccharides, oxidation of indole-3-acetic acid, regulation of cell elongation, wound-healing, phenol oxidation, and pathogen defense. However, due to the many different isoenzymes and even more potential substrates, it has proven difficult to verify actual physiological roles for peroxidase. We are studying the molecular biology of the tobacco peroxidase genes, and have utilized genetic engineering techniques to produce transgenic plants which differ only in their expression of an individual peroxidase isoenzyme. Many of the in planta functions for any individual isoenzyme may be predicted through the morphological and physiological analysis of transformed plants.

  12. Zn2+ -induced changes at the root level account for the increased tolerance of acclimated tobacco plants.

    PubMed

    Bazihizina, Nadia; Taiti, Cosimo; Marti, Lucia; Rodrigo-Moreno, Ana; Spinelli, Francesco; Giordano, Cristiana; Caparrotta, Stefania; Gori, Massimo; Azzarello, Elisa; Mancuso, Stefano

    2014-09-01

    Evidence suggests that heavy-metal tolerance can be induced in plants following pre-treatment with non-toxic metal concentrations, but the results are still controversial. In the present study, tobacco plants were exposed to increasing Zn2+ concentrations (up to 250 and/or 500 μM ZnSO4) with or without a 1-week acclimation period with 30 μM ZnSO4. Elevated Zn2+ was highly toxic for plants, and after 3 weeks of treatments there was a marked (≥50%) decline in plant growth in non-acclimated plants. Plant acclimation, on the other hand, increased plant dry mass and leaf area up to 1.6-fold compared with non-acclimated ones. In non-acclimated plants, the addition of 250 μM ZnSO4 led to transient membrane depolarization and stomatal closure within 24h from the addition of the stress; by contrast, the acclimation process was associated with an improved stomatal regulation and a superior ability to maintain a negative root membrane potential, with values on average 37% more negative compared with non-acclimated plants. The different response at the plasma-membrane level between acclimated and non-acclimated plants was associated with an enhanced vacuolar Zn2+ sequestration and up to 2-fold higher expression of the tobacco orthologue of the Arabidopsis thaliana MTP1 gene. Thus, the acclimation process elicited specific detoxification mechanisms in roots that enhanced Zn2+ compartmentalization in vacuoles, thereby improving root membrane functionality and stomatal regulation in leaves following elevated Zn2+ stress.

  13. Zn2+-induced changes at the root level account for the increased tolerance of acclimated tobacco plants

    PubMed Central

    Bazihizina, Nadia; Taiti, Cosimo; Marti, Lucia; Rodrigo-Moreno, Ana; Spinelli, Francesco; Giordano, Cristiana; Caparrotta, Stefania; Gori, Massimo; Azzarello, Elisa; Mancuso, Stefano

    2014-01-01

    Evidence suggests that heavy-metal tolerance can be induced in plants following pre-treatment with non-toxic metal concentrations, but the results are still controversial. In the present study, tobacco plants were exposed to increasing Zn2+ concentrations (up to 250 and/or 500 μM ZnSO4) with or without a 1-week acclimation period with 30 μM ZnSO4. Elevated Zn2+ was highly toxic for plants, and after 3 weeks of treatments there was a marked (≥50%) decline in plant growth in non-acclimated plants. Plant acclimation, on the other hand, increased plant dry mass and leaf area up to 1.6-fold compared with non-acclimated ones. In non-acclimated plants, the addition of 250 μM ZnSO4 led to transient membrane depolarization and stomatal closure within 24h from the addition of the stress; by contrast, the acclimation process was associated with an improved stomatal regulation and a superior ability to maintain a negative root membrane potential, with values on average 37% more negative compared with non-acclimated plants. The different response at the plasma-membrane level between acclimated and non-acclimated plants was associated with an enhanced vacuolar Zn2+ sequestration and up to 2-fold higher expression of the tobacco orthologue of the Arabidopsis thaliana MTP1 gene. Thus, the acclimation process elicited specific detoxification mechanisms in roots that enhanced Zn2+ compartmentalization in vacuoles, thereby improving root membrane functionality and stomatal regulation in leaves following elevated Zn2+ stress. PMID:24928985

  14. Plant cell wall proteomics: the leadership of Arabidopsis thaliana

    PubMed Central

    Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth

    2013-01-01

    Plant cell wall proteins (CWPs) progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses, and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose, and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cell walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last 10 years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i) a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii) the main protein families identified and the still missing peptides; (iii) the persistent issue of the non-canonical CWPs; (iv) the present challenges to overcome technological bottlenecks; and (v) the perspectives beyond cell wall proteomics to understand CWP functions. PMID:23641247

  15. Human intrinsic factor expressed in the plant Arabidopsis thaliana.

    PubMed

    Fedosov, Sergey N; Laursen, Niels B; Nexø, Ebba; Moestrup, Søren K; Petersen, Torben E; Jensen, Erik Ø; Berglund, Lars

    2003-08-01

    Intrinsic factor (IF) is the gastric protein that promotes the intestinal uptake of vitamin B12. Gastric IF from animal sources is used in diagnostic tests and in vitamin pills. However, administration of animal IF to humans becomes disadvantageous because of possible pathogenic transmission and contamination by other B12 binders. We tested the use of recombinant plants for large-scale production of pathogen-free human recombinant IF. Human IF was successfully expressed in the recombinant plant Arabidopsis thaliana. Extract from fresh plants possessed high B12-binding capacity corresponding to 70 mg IF per 1 kg wet weight. The dried plants still retained 60% of the IF activity. The purified IF preparation consisted of a 50-kDa glycosylated protein with the N-terminal sequence of mature IF. Approximately one-third of the protein was cleaved at the internal site em leader PSNP downward arrow GPGP. The key properties of the preparation obtained were identical to those of native IF: the binding curves of vitamin B12 to recombinant IF and gastric IF were the same, as were those for a B12 analogue cobinamide, which binds to IF with low affinity. The absorbance spectra of the vitamin bound to recombinant IF and gastric IF were alike, as was the interaction of recombinant and native IF with the specific receptor cubilin. The data presented show that recombinant plants have a great potential as a large-scale source of human IF for analytical and therapeutic purposes.

  16. Plant cell wall proteomics: the leadership of Arabidopsis thaliana.

    PubMed

    Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth

    2013-01-01

    Plant cell wall proteins (CWPs) progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses, and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose, and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cell walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last 10 years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i) a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii) the main protein families identified and the still missing peptides; (iii) the persistent issue of the non-canonical CWPs; (iv) the present challenges to overcome technological bottlenecks; and (v) the perspectives beyond cell wall proteomics to understand CWP functions.

  17. An acidic class III chitinase in sugar beet: induction by Cercospora beticola, characterization, and expression in transgenic tobacco plants.

    PubMed

    Nielsen, K K; Mikkelsen, J D; Kragh, K M; Bojsen, K

    1993-01-01

    An acidic chitinase (SE) was found to accumulate in leaves of sugar beet (Beta vulgaris) during infection with Cercospora beticola. Two isoforms, SE1 and SE2, with MW of 29 kDa and pI of approximately 3.0 were purified to homogeneity. SE2 is an endochitinase that also exhibits exochitinase activity, i.e., it is capable of hydrolyzing chito-oligosaccharides, including chitobiose, into N-acetyl-glucosamine. Partial amino acid sequence data for SE2 were used to obtain a cDNA clone by polymerase chain reaction. The clone was used to isolate a cDNA clone encoding SE2. The deduced amino acid sequence for SE2 is 58-67% identical to the class III chitinases from cucumber, Arabidopsis, and tobacco. A transient induction of SE2 mRNA during the early stages of infection with C. beticola is much stronger in tolerant plants than in susceptible plants. Transgenic tobacco (Nicotiana benthamiana) plants constitutively accumulate SE2 protein in the intercellular space of their leaves. In a preliminary infection experiment, the transgenic plants did not show increase in resistance against C. nicotianae.

  18. [Estradiol inducible and flower-specific expression of ARGOS and ARGOS-LIKE genes in transgenic tobacco plants].

    PubMed

    Kuluev, B R; Kniazev, A V; Nikonorov, Iu M; Cheremis, A V

    2014-08-01

    Transgenic tobacco plants expressing Arabidopsis thaliana ARGOS and ARGOS-LIKE genes under the control of the chalcone synthase promoter of Petunia hybrid L., as well as the estradiol inducible XVE system, have been obtained. The part of transgenic plants with flower-specific expression of the target genes was characterized by increased flower size, caused by an increase in cell size and quantity in the case of the ARGOS gene and by a stimulation of cell growth via stretching in the case of the ARGOS-LIKE gene. An enhanced expression level of the NtEXPA1, NtEXPA4 genes encoding expansins, NtEXGT gene encoding endo-xyloglucan transferase, and the AINTEGUMENTA-like gene was detected in the flowers of transgenic tobacco plants. In the case of inducible expression of ARGOS and ARGOS-LIKE genes, an increase in leaf, stem and flower size was revealed in several lines of transgenic plants as compared to control. Expression of the ARGOS gene also affected cell number and size in this case, while the ARGOS-LIKE gene mainly influenced cell size via stretching. Inducible expression of the ARGOS gene in flowers mainly provided an enhanced containment of AINTEGUMENTA-like mRNA, while ARGOS-LIKE gene expression resulted in the activation of NtEXPA1 and NtEXGT genes.

  19. The plant Apolipoprotein D ortholog protects Arabidopsis against oxidative stress

    PubMed Central

    Charron, Jean-Benoit F; Ouellet, Francois; Houde, Mario; Sarhan, Fathey

    2008-01-01

    Background Lipocalins are a large and diverse family of small, mostly extracellular proteins implicated in many important functions. This family has been studied in bacteria, invertebrate and vertebrate animals but little is known about these proteins in plants. We recently reported the identification and molecular characterization of the first true lipocalins from plants, including the Apolipoprotein D ortholog AtTIL identified in the plant model Arabidopsis thaliana. This study aimed to determine its physiological role in planta. Results Our results demonstrate that the AtTIL lipocalin is involved in modulating tolerance to oxidative stress. AtTIL knock-out plants are very sensitive to sudden drops in temperature and paraquat treatment, and dark-grown plants die shortly after transfer to light. These plants accumulate a high level of hydrogen peroxide and other ROS, which causes an oxidative stress that is associated with a reduction in hypocotyl growth and sensitivity to light. Complementation of the knock-out plants with the AtTIL cDNA restores the normal phenotype. On the other hand, overexpression enhances tolerance to stress caused by freezing, paraquat and light. Moreover, this overexpression delays flowering and maintains leaf greenness. Microarray analyses identified several differentially-regulated genes encoding components of oxidative stress and energy balance. Conclusion This study provides the first functional evidence that a plant lipocalin is involved in modulating tolerance to oxidative stress. These findings are in agreement with recently published data showing that overexpression of ApoD enhances tolerance to oxidative stress and increases life span in mice and Drosophila. Together, the three papers strongly support a similar function of lipocalins in these evolutionary-distant species. PMID:18671872

  20. Overexpression of MzASMT improves melatonin production and enhances drought tolerance in transgenic Arabidopsis thaliana plants.

    PubMed

    Zuo, Bixiao; Zheng, Xiaodong; He, Pingli; Wang, Lin; Lei, Qiong; Feng, Chao; Zhou, Jingzhe; Li, Qingtian; Han, Zhenhai; Kong, Jin

    2014-11-01

    Melatonin is a potent naturally occurring reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenger in plants. Melatonin protects plants from oxidative stress and, therefore, it improves their tolerance against a variety of environmental abiotic stressors. N-acetylserotonin-O-methyltransferase (ASMT) is a specific enzyme required for melatonin synthesis. In this report, an ASMT gene was cloned from apple rootstock (Malus zumi Mats) and designated as MzASMT1 (KJ123721). The MzASMT1 expression was induced by drought stress in apple leaves. The upregulation of MzASMT1 in the apple leaf positively relates to melatonin production over a 24-hr dark/light cycle. Purified MzASMT1 protein expressed in E. coli converted its substrates to melatonin with an activity of approximately 5.5 pmol/min/mg protein. The transient transformation in tobacco identified that MzASMT1 is located in cytoplasm of the cell. When MzASMT1 gene driven by 35S promoter was transferred to Arabidopsis, melatonin levels in transgenic Arabidopsis plants were 2-4 times higher than those in the wild type. The transgenic Arabidopsis plants had significantly lower intrinsic ROS than the wild type and therefore these plants exhibited greater tolerance to drought stress than that of wild type. This is, at least partially, attributed to the elevated melatonin levels resulting from the overexpression of MzASMT1. The results elucidated the important role that membrane-located melatonin synthase plays in drought tolerance. These findings have significant implications in agriculture.

  1. Comparison of methods for extracting thylakoid membranes of Arabidopsis plants.

    PubMed

    Chen, Yang-Er; Yuan, Shu; Schröder, Wolfgang P

    2016-01-01

    Robust and reproducible methods for extracting thylakoid membranes are required for the analysis of photosynthetic processes in higher plants such as Arabidopsis. Here, we compare three methods for thylakoid extraction using two different buffers. Method I involves homogenizing the plant material with a metal/glass blender; method II involves manually grinding the plant material in ice-cold grinding buffer with a mortar and method III entails snap-freezing followed by manual grinding with a mortar, after which the frozen powder is thawed in isolation buffer. Thylakoid membrane samples extracted using each method were analyzed with respect to protein and chlorophyll content, yields relative to starting material, oxygen-evolving activity, protein complex content and phosphorylation. We also examined how the use of fresh and frozen thylakoid material affected the extracts' contents of protein complexes. The use of different extraction buffers did not significantly alter the protein content of the extracts in any case. Method I yielded thylakoid membranes with the highest purity and oxygen-evolving activity. Method III used low amounts of starting material and was capable of capturing rapid phosphorylation changes in the sample at the cost of higher levels of contamination. Method II yielded thylakoid membrane extracts with properties intermediate between those obtained with the other two methods. Finally, frozen and freshly isolated thylakoid membranes performed identically in blue native-polyacrylamide gel electrophoresis experiments conducted in order to separate multimeric protein supracomplexes. © 2015 Scandinavian Plant Physiology Society.

  2. Identification and dynamics of two classes of aurora-like kinases in Arabidopsis and other plants.

    PubMed

    Demidov, Dmitri; Van Damme, Daniël; Geelen, Danny; Blattner, Frank R; Houben, Andreas

    2005-03-01

    Aurora-like kinases play key roles in chromosome segregation and cytokinesis in yeast, plant, and animal systems. Here, we characterize three Arabidopsis thaliana protein kinases, designated AtAurora1, AtAurora2, and AtAurora3, which share high amino acid identities with the Ser/Thr kinase domain of yeast Ipl1 and animal Auroras. Structure and expression of AtAurora1 and AtAurora2 suggest that these genes arose by a recent gene duplication, whereas the diversification of plant alpha and beta Aurora kinases predates the origin of land plants. The transcripts and proteins of all three kinases are most abundant in tissues containing dividing cells. Intracellular localization of green fluorescent protein-tagged AtAuroras revealed an AtAurora-type specific association mainly with dynamic mitotic structures, such as microtubule spindles and centromeres, and with the emerging cell plate of dividing tobacco (Nicotiana tabacum) BY-2 cells. Immunolabeling using AtAurora antibodies yielded specific signals at the centromeres that are coincident with histone H3 that is phosphorylated at Ser position10 during mitosis. An in vitro kinase assay demonstrated that AtAurora1 preferentially phosphorylates histone H3 at Ser 10 but not at Ser 28 or Thr 3, 11, and 32. The phylogenetic analysis of available Aurora sequences from different eukaryotic origins suggests that, although a plant Aurora gene has been duplicated early in the evolution of plants, the paralogs nevertheless maintained a role in cell cycle-related signal transduction pathways.

  3. Expressions of thermostable bacterial cellulases in tobacco plant.

    PubMed

    Jiang, Xi-ran; Zhou, Xiao-ya; Jiang, Wen-yan; Gao, Xiao-rong; Li, Wen-li

    2011-09-01

    An economical method for the conversion of lignocellulosic biomass is to use plants as bioreactors for cellulases production. Two bacterial thermostable cellulases (E2 and E3) and a E3-E2 fusion form were expressed in tobacco, driven by a double 35S promoter and 5' TEV-UTL. The enzymes were targeted to the apoplast and cytosol via 5' signal peptides and 3' retention signal peptides, respectively, and all showed functional activities. All transgenic plants exhibited normal growth compared to wild type. Transgenic plants that expressed apoplast-localized E2 had the highest average activity, about 1.5 and 3 times higher than those expressed ER-localized and cytosolic E2, respectively. Effect of subcellular compartment localization was due primarily to post-transcriptional modification, since mRNA abundances were similar despite the range of cellulase activities obtained. The recombinant cellulases exhibited good thermostability below 65 °C. After storing for 3 days at -20 and 28 °C, the enzymes lost nearly 20 and 80% of activity, respectively. The results suggested a potential application for heterologous expression of cellulases in plant for biomass conversion. © Springer Science+Business Media B.V. 2011

  4. Over-expression of STP13, a hexose transporter, improves plant growth and nitrogen use in Arabidopsis thaliana seedlings.

    PubMed

    Schofield, R A; Bi, Y-M; Kant, S; Rothstein, S J

    2009-03-01

    In Arabidopsis thaliana, the regulation of hexose levels by the large monosaccharide transporter (MST) gene family influences many aspects of plant growth. The cloning and transgenic expression of one family member (STP13) enabled the manipulation of carbon (C) and nitrogen (N) metabolism in Arabidopsis. Transgenic seedlings constitutively over-expressing STP13 (STP13OX) had increased rates of glucose uptake, higher endogenous sucrose levels and accumulated more total C and biomass per plant when grown on soil-less media supplemented with 55 mM glucose and sufficient N (9 mM nitrate). Furthermore, STP13OX seedlings acquired 90% more total N than the Col-0 seedlings, and had higher levels of expression of the nitrate transporter NRT2.2. In addition, STP13OX seedlings were larger and had higher biomass than Col-0 seedlings when grown under a limiting N condition (3 mM nitrate). Transgene analysis of STP13 reveals that its gene product is localized to the plasma membrane (PM) in tobacco BY-2 suspension cells, that it encodes a functional MST in planta, and that the STP13 promoter directs GUS expression to the vasculature and to leaf mesophyll cells. This work highlights the link between C and N metabolism, demonstrating that a plant's N use may be improved by increasing the availability of C.

  5. Overexpression of a tobacco small G protein gene NtRop1 causes salt sensitivity and hydrogen peroxide production in transgenic plants.

    PubMed

    Cao, YangRong; Li, ZhiGang; Chen, Tao; Zhang, ZhiGang; Zhang, JinSong; Chen, ShouYi

    2008-05-01

    The small GTPases of Rop/Rho family is central regulators of important cellular processes in plants. Tobacco small G protein gene NtRop1 has been isolated; however, its roles in stress responses were unknown. In the present study, the genomic sequence of NtRop1 was cloned, which has seven exons and six introns, similar to the Rop gene structure from Arabidopsis. The NtRop1 gene was constitutively expressed in the different organs whereas the other six Rop genes from tobacco had differential expression patterns. The expression of the NtRop1 gene was moderately induced by methyl viologen, NaCl, and ACC treatments, but slightly inhibited by ABA treatment, with no significant induction by NAA treatment. The transgenic Arabidopsis plants overexpressing the NtRop1 showed increased salt sensitivity as can be seen from the reduced root growth and elevated relative electrolyte leakage. The hydrogen peroxide production was also promoted in the NtRop1-trangenic plants in comparison with wild type plants. These results imply that the NtRop1 may confer salt sensitivity through activation of H2O2 production during plant response to salt stress.

  6. Oil content of Arabidopsis seeds: the influence of seed anatomy, light and plant-to-plant variation.

    PubMed

    Li, Yonghua; Beisson, Fred; Pollard, Mike; Ohlrogge, John

    2006-05-01

    Arabidopsis thaliana is frequently used as a model for the study of oilseed biology and metabolism. However, the very small seeds of Arabidopsis can complicate analysis of their oil content and influence the application of results to larger-seeded plants. Here, we describe how seed anatomy, light, and plant-to-plant variation influence the content and measurement of oil in Arabidopsis seeds. The anatomy of Arabidopsis and Brassica napus seeds were compared and the distribution of mass, oil and the fatty acid composition of different seed parts were determined. In Brassica, 90% of the seed oil resides in the cotyledons that contribute 74% of seed mass. By contrast, the values for Arabidopsis are 60% and 45%, respectively, with a higher fraction of the oil deposited in the radicle, hypocotyl, endosperm and seed coat. Growth of Arabidopsis plants with 600 micromol m(-2) s(-1) light resulted in a two-fold higher seed yield, a 40% increase in mass per seed and a 60% increase in oil per seed compared to growth at 100 micromol m(-2) s(-1). Factors that influence the analysis of oil content were evaluated. Intact-seed transmethylation followed by gas chromatography (GC) analysis provided reproducible analysis of Arabidopsis seed oil. However, plant-to-plant variation in oil content is large and we analyzed how this influences the ability to detect statistically valid changes in oil between different genotypes. These observations establish a reference data set on the fatty acid composition and distribution of mass and oil between tissues of Arabidopsis seeds that should help to predict the applicability of results obtained with Arabidopsis to other oilseeds.

  7. The Plant Vacuolar Sorting Receptor Atelp Is Involved in Transport of Nh2-Terminal Propeptide-Containing Vacuolar Proteins in Arabidopsis thaliana

    PubMed Central

    Ahmed, Sharif U.; Rojo, Enrique; Kovaleva, Valentina; Venkataraman, Sridhar; Dombrowski, James E.; Matsuoka, Ken; Raikhel, Natasha V.

    2000-01-01

    Many soluble plant vacuolar proteins are sorted away from secreted proteins into small vesicles at the trans-Golgi network by transmembrane cargo receptors. Cleavable vacuolar sorting signals include the NH2-terminal propeptide (NTPP) present in sweet potato sporamin (Spo) and the COOH-terminal propeptide (CTPP) present in barley lectin (BL). These two proteins have been found to be transported by different mechanisms to the vacuole. We examined the ability of the vacuolar cargo receptor AtELP to interact with the sorting signals of heterologous and endogenous plant vacuolar proteins in mediating vacuolar transport in Arabidopsis thaliana. AtELP extracted from microsomes was found to interact with the NTPPs of barley aleurain and Spo, but not with the CTPPs of BL or tobacco chitinase, in a pH-dependent and sequence-specific manner. In addition, EM studies revealed the colocalization of AtELP with NTPP-Spo at the Golgi apparatus, but not with BL-CTPP in roots of transgenic Arabidopsis plants. Further, we found that AtELP interacts in a similar manner with the NTPP of the endogenous vacuolar protein AtALEU (Arabidopsis thaliana Aleu), a protein highly homologous to barley aleurain. We hypothesize that AtELP functions as a vacuolar sorting receptor involved in the targeting of NTPP-, but not CTPP-containing proteins in Arabidopsis. PMID:10871276

  8. Plant coexistence can enhance phytoextraction of cadmium by tobacco (Nicotiana tabacum L.) in contaminated soil.

    PubMed

    Liu, Ling; Li, Yuefang; Tang, Jianjun; Hu, Liangliang; Chen, Xin

    2011-01-01

    A mesocosm experiment was conducted to investigate whether plant coexistence affects cadmium (Cd) uptake by plant in contaminated soil. Tobacco (Nicotiana tabacum L. var. K326) and Japanese clover (Kummerowia striata (Thunb.) Schindl.) were used. Cadmium was applied as 3CdSO4 x 8H2O in solution at three levels (0, 1, and 3 mg/kg soil) to simulate an unpolluted soil and soils that were slightly and moderately polluted with Cd. Tobacco (crop), Japanese clover (non-crop), and their combination were grown under each Cd treatment. Compared to monoculture and under all Cd treatments, co-planting with Japanese clover did not affect tobacco biomass but significantly increased Cd concentration in all tobacco tissues and enhanced Cd accumulation in tobacco shoots and roots. Compared to monoculture, co-planting reduced soil pH and increased Cd bioavailability. For tobacco, co-planting with Japanese clover increased the Cd bioconcentration factor (BCF) in Cd contaminated soil. Japanese clover also accumulated substantial quantities of Cd in shoots and roots. Thus, total Cd uptake by the plants was much greater with co-planting than with monoculture. The results suggested that phytoextraction can be effectively increased through tobacco co-planting with Japanese clover in mildly Cd-contaminated soil.

  9. 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

  10. Increased sedoheptulose-1,7-bisphosphatase activity in transgenic tobacco plants stimulates photosynthesis and growth from an early stage in development.

    PubMed

    Lefebvre, Stephane; Lawson, Tracy; Zakhleniuk, Oksana V; Lloyd, Julie C; Raines, Christine A; Fryer, Mike

    2005-05-01

    Activity of the Calvin cycle enzyme sedoheptulose-1,7-bisphosphatase (SBPase) was increased by overexpression of an Arabidopsis (Arabidopsis thaliana) cDNA in tobacco (Nicotiana tabacum) plants. In plants with increased SBPase activity, photosynthetic rates were increased, higher levels of Suc and starch accumulated during the photoperiod, and an increase in leaf area and biomass of up to 30% was also evident. Light saturated photosynthesis increased with increasing SBPase activity and analysis of CO2 response curves revealed that this increase in photosynthesis could be attributed to an increase in ribulose 1,5-bisphosphate regenerative capacity. Seedlings with increased SBPase activity had an increased leaf area at the 4 to 5 leaf stage when compared to wild-type plants, and chlorophyll fluorescence imaging of these young plants revealed a higher photosynthetic capacity at the whole plant level. Measurements of photosynthesis, made under growth conditions integrated over the day, showed that mature plants with increased SBPase activity fixed 6% to 12% more carbon than equivalent wild-type leaves, with the young leaves having the highest rates. In this paper, we have shown that photosynthetic capacity per unit area and plant yield can be increased by overexpressing a single native plant enzyme, SBPase, and that this gives an advantage to the growth of these plants from an early phase of vegetative growth. This work has also shown that it is not necessary to bypass the normal regulatory control of SBPase, exerted by conditions in the stroma, to achieve improvements in carbon fixation.

  11. Arabidopsis CAP regulates the actin cytoskeleton necessary for plant cell elongation and division.

    PubMed

    Barrero, Roberto A; Umeda, Masaaki; Yamamura, Saburo; Uchimiya, Hirofumi

    2002-01-01

    An Arabidopsis cDNA (AtCAP1) that encodes a predicted protein of 476 amino acids highly homologous with the yeast cyclase-associated protein (CAP) was isolated. Expression of AtCAP1 in the budding yeast CAP mutant was able to rescue defects such as abnormal cell morphology and random budding pattern. The C-terminal domain, 158 amino acids of AtCAP1 possessing in vitro actin binding activity, was needed for the regulation of cytoskeleton-related defects of yeast. Transgenic plants overexpressing AtCAP1 under the regulation of a glucocorticoid-inducible promoter showed different levels of AtCAP1 accumulation related to the extent of growth abnormalities, in particular size reduction of leaves as well as petioles. Morphological alterations in leaves were attributable to decreased cell size and cell number in both epidermal and mesophyll cells. Tobacco suspension-cultured cells (Bright Yellow 2) overexpressing AtCAP1 exhibited defects in actin filaments and were unable to undergo mitosis. Furthermore, an immunoprecipitation experiment suggested that AtCAP1 interacted with actin in vivo. Therefore, AtCAP1 may play a functional role in actin cytoskeleton networking that is essential for proper cell elongation and division.

  12. Transcriptional responses of Arabidopsis thaliana plants to As (V) stress

    PubMed Central

    Abercrombie, Jason M; Halfhill, Matthew D; Ranjan, Priya; Rao, Murali R; Saxton, Arnold M; Yuan, Joshua S; Stewart, C Neal

    2008-01-01

    Background Arsenic is toxic to plants and a common environmental pollutant. There is a strong chemical similarity between arsenate [As (V)] and phosphate (Pi). Whole genome oligonucleotide microarrays were employed to investigate the transcriptional responses of Arabidopsis thaliana plants to As (V) stress. Results Antioxidant-related genes (i.e. coding for superoxide dismutases and peroxidases) play prominent roles in response to arsenate. The microarray experiment revealed induction of chloroplast Cu/Zn superoxide dismutase (SOD) (at2g28190), Cu/Zn SOD (at1g08830), as well as an SOD copper chaperone (at1g12520). On the other hand, Fe SODs were strongly repressed in response to As (V) stress. Non-parametric rank product statistics were used to detect differentially expressed genes. Arsenate stress resulted in the repression of numerous genes known to be induced by phosphate starvation. These observations were confirmed with qRT-PCR and SOD activity assays. Conclusion Microarray data suggest that As (V) induces genes involved in response to oxidative stress and represses transcription of genes induced by phosphate starvation. This study implicates As (V) as a phosphate mimic in the cell by repressing genes normally induced when available phosphate is scarce. Most importantly, these data reveal that arsenate stress affects the expression of several genes with little or unknown biological functions, thereby providing new putative gene targets for future research. PMID:18684332

  13. Tobacco

    MedlinePlus

    ... from poor households are frequently employed in tobacco farming to provide family income. These children are especially ... 19% of the world's population, meet the best practice for pictorial warnings, which includes the warnings in ...

  14. Arabidopsis PED2 positively modulates plant drought stress resistance.

    PubMed

    Shi, Haitao; Ye, Tiantian; Yang, Fan; Chan, Zhulong

    2015-09-01

    Abscisic acid (ABA) is an important phytohormone that functions in seed germination, plant development, and multiple stress responses. Arabidopsis Peroxisome defective 2 (AtPED2) (also known as AtPEXOXIN14, AtPEX14), is involved in the intracellular transport of thiolase from the cytosol to glyoxysomes, and perosisomal matrix protein import in plants. In this study, we assigned a new role for AtPED2 in drought stress resistance. The transcript level of AtPED2 was downregulated by ABA and abiotic stress treatments. AtPED2 knockout mutants were insensitive to ABA-mediated seed germination, primary root elongation, and stomatal response, while AtPED2 over-expressing plants were sensitive to ABA in comparison to wide type (WT). AtPED2 also positively regulated drought stress resistance, as evidenced by the changes of water loss rate, electrolyte leakage, and survival rate. Notably, AtPED2 positively modulated expression of several stress-responsive genes (RAB18, RD22, RD29A, and RD29B), positively affected underlying antioxidant enzyme activities and negatively regulated reactive oxygen species (ROS) level under drought stress conditions. Moreover, multiple carbon metabolites including amino acids, organic acids, sugars, sugar alcohols, and aromatic amines were also positively regulated by AtPED2. Taken together, these results indicated a positive role for AtPED2 in drought resistance, through modulation of stress-responsive genes expression, ROS metabolism, and metabolic homeostasis, at least partially. © 2015 Institute of Botany, Chinese Academy of Sciences.

  15. Grapevine and Arabidopsis Cation-Chloride Cotransporters Localize to the Golgi and Trans-Golgi Network and Indirectly Influence Long-Distance Ion Transport and Plant Salt Tolerance.

    PubMed

    Henderson, Sam W; Wege, Stefanie; Qiu, Jiaen; Blackmore, Deidre H; Walker, Amanda R; Tyerman, Stephen D; Walker, Rob R; Gilliham, Matthew

    2015-11-01

    Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. They are predicted to improve shoot salt exclusion by directly catalyzing the retrieval of sodium (Na(+)) and chloride (Cl(-)) ions from the root xylem. We investigated whether grapevine (Vitis vinifera [Vvi]) CCC has a role in salt tolerance by cloning and functionally characterizing the gene from the cultivar Cabernet Sauvignon. Amino acid sequence analysis revealed that VviCCC shares a high degree of similarity with other plant CCCs. A VviCCC-yellow fluorescent protein translational fusion protein localized to the Golgi and the trans-Golgi network and not the plasma membrane when expressed transiently in tobacco (Nicotiana benthamiana) leaves and Arabidopsis (Arabidopsis thaliana) mesophyll protoplasts. AtCCC-green fluorescent protein from Arabidopsis also localized to the Golgi and the trans-Golgi network. In Xenopus laevis oocytes, VviCCC targeted to the plasma membrane, where it catalyzed bumetanide-sensitive (36)Cl(-), (22)Na(+), and (86)Rb(+) uptake, suggesting that VviCCC (like AtCCC) belongs to the Na(+)-K(+)-2Cl(-) cotransporter class of CCCs. Expression of VviCCC in an Arabidopsis ccc knockout mutant abolished the mutant's stunted growth phenotypes and reduced shoot Cl(-) and Na(+) content to wild-type levels after growing plants in 50 mm NaCl. In grapevine roots, VviCCC transcript abundance was not regulated by Cl(-) treatment and was present at similar levels in both the root stele and cortex of three Vitis spp. genotypes that exhibit differential shoot salt exclusion. Our findings indicate that CCC function is conserved between grapevine and Arabidopsis, but neither protein is likely to directly mediate ion transfer with the xylem or have a direct role in salt tolerance. © 2015 American Society of Plant Biologists. All Rights Reserved.

  16. Isoprene emission protects photosynthesis but reduces plant productivity during drought in transgenic tobacco (Nicotiana tabacum) plants.

    PubMed

    Ryan, Annette C; Hewitt, C Nicholas; Possell, Malcolm; Vickers, Claudia E; Purnell, Anna; Mullineaux, Philip M; Davies, William J; Dodd, Ian C

    2014-01-01

    Isoprene protects the photosynthetic apparatus of isoprene-emitting plants from oxidative stress. The role of isoprene in the response of plants to drought is less clear. Water was withheld from transgenic isoprene-emitting and non-emitting tobacco (Nicotiana tabacum) plants, to examine: the response of isoprene emission to plant water deficit; a possible relationship between concentrations of the drought-induced phytohormone abscisic acid (ABA) and isoprene; and whether isoprene affected foliar reactive oxygen species (ROS) and lipid peroxidation levels. Isoprene emission did not affect whole-plant water use, foliar ABA concentration or leaf water potential under water deficit. Compared with well-watered controls, droughted non-emitting plants significantly increased ROS content (31-46%) and lipid peroxidation (30-47%), concomitant with decreased operating and maximum efficiencies of photosystem II photochemistry and lower leaf and whole-plant water use efficiency (WUE). Droughted isoprene-emitting plants showed no increase in ROS content or lipid peroxidation relative to well-watered controls, despite isoprene emission decreasing before leaf wilting. Although isoprene emission protected the photosynthetic apparatus and enhanced leaf and whole-plant WUE, non-emitting plants had 8-24% more biomass under drought, implying that isoprene emission incurred a yield penalty. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  17. Production of Haploid Tobacco Plants Using Anther Culture.

    ERIC Educational Resources Information Center

    Smith, Robert A.; Belzer, Norbert F.

    2002-01-01

    Presents a tobacco haploid experiment in which students learn the cytogenetic technique of metaphase analysis of chromosomes and experience the basic principles of haploidy, diploidy, and polyploidy. (YDS)

  18. Production of Haploid Tobacco Plants Using Anther Culture.

    ERIC Educational Resources Information Center

    Smith, Robert A.; Belzer, Norbert F.

    2002-01-01

    Presents a tobacco haploid experiment in which students learn the cytogenetic technique of metaphase analysis of chromosomes and experience the basic principles of haploidy, diploidy, and polyploidy. (YDS)

  19. A multiplex reverse transcription PCR assay for simultaneous detection of five tobacco viruses in tobacco plants.

    PubMed

    Dai, Jin; Cheng, Julong; Huang, Ting; Zheng, Xuan; Wu, Yunfeng

    2012-07-01

    Tobacco viruses including Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Tobacco etch virus (TEV), Potato virus Y (PVY) and Tobacco vein banding mosaic virus (TVBMV) are major viruses infecting tobacco and can cause serious crop losses. A multiplex reverse transcription polymerase chain reaction assay was developed to detect simultaneously and differentiate all five viruses. The system used specific primer sets for each virus producing five distinct fragments 237, 273, 347, 456 and 547 bp, representing TMV, CMV subgroup I, TEV, PVY(O) and TVBMV, respectively. These primers were used for detection of the different viruses by single PCR and multiplex PCR and the results were confirmed by DNA sequencing analysis. The protocol was used to detect viruses from different parts of China. The simultaneous and sensitive detection of different viruses using the multiplex PCR is more efficient and economical than other conventional methods for tobacco virus detection. This multiplex PCR provides a rapid and reliable method for the detection and identification of major tobacco viruses, and will be useful for epidemiological studies.

  20. Overexpression of OsRAN2 in rice and Arabidopsis renders transgenic plants hypersensitive to salinity and osmotic stress.

    PubMed

    Zang, Aiping; Xu, Xiaojie; Neill, Steven; Cai, Weiming

    2010-03-01

    Nucleo-cytoplasmic partitioning of regulatory proteins is increasingly being recognized as a major control mechanism for the regulation of signalling in plants. Ras-related nuclear protein (Ran) GTPase is required for regulating transport of proteins and RNA across the nuclear envelope and also has roles in mitotic spindle assembly and nuclear envelope (NE) assembly. However, thus far little is known of any Ran functions in the signalling pathways in plants in response to changing environmental stimuli. The OsRAN2 gene, which has high homology (77% at the amino acid level) with its human counterpart, was isolated here. Subcellular localization results showed that OsRan2 is mainly localized in the nucleus, with some in the cytoplasm. Transcription of OsRAN2 was reduced by salt, osmotic, and exogenous abscisic acid (ABA) treatments, as determined by real-time PCR. Overexpression of OsRAN2 in rice resulted in enhanced sensitivity to salinity, osmotic stress, and ABA. Seedlings of transgenic Arabidopsis thaliana plants overexpressing OsRAN2 were overly sensitive to salinity stress and exogenous ABA treatment. Furthermore, three ABA- or stress-responsive genes, AtNCED3, AtPLC1, and AtMYB2, encoding a key enzyme in ABA synthesis, a phospholipase C homologue, and a putative transcriptional factor, respectively, were shown to have differentially induced expression under salinity and ABA treatments in transgenic and wild-type Arabidopsis plants. OsRAN2 overexpression in tobacco epidermal leaf cells disturbed the nuclear import of a maize (Zea mays L.) leaf colour transcription factor (Lc). In addition, gene-silenced rice plants generated via RNA interference (RNAi) displayed pleiotropic developmental abnormalities and were male sterile.

  1. Effect of Yeast CTA1 Gene Expression on Response of Tobacco Plants to Tobacco Mosaic Virus Infection1

    PubMed Central

    Talarczyk, Andrzej; Krzymowska, Magdalena; Borucki, Wojciech; Hennig, Jacek

    2002-01-01

    The response of tobacco (Nicotiana tabacum L. cv Xanthi-nc) plants with elevated catalase activity was studied after infection by tobacco mosaic virus (TMV). These plants contain the yeast (Saccharomyces cerevisiae) peroxisomal catalase gene CTA1 under the control of the cauliflower mosaic virus 35S promoter. The transgenic lines exhibited 2- to 4-fold higher total in vitro catalase activity than untransformed control plants under normal growth conditions. Cellular localization of the CTA1 protein was established using immunocytochemical analysis. Gold particles were detected mainly inside peroxisomes, whereas no significant labeling was detected in other cellular compartments or in the intercellular space. The physiological state of the transgenic plants was evaluated in respect to growth rate, general appearance, carbohydrate content, and dry weight. No significant differences were recorded in comparison with non-transgenic tobacco plants. The 3,3′-diaminobenzidine-stain method was applied to visualize hydrogen peroxide (H2O2) in the TMV infected tissue. Presence of H2O2 could be detected around necrotic lesions caused by TMV infection in non-transgenic plants but to a much lesser extent in the CTA1 transgenic plants. In addition, the size of necrotic lesions was significantly bigger in the infected leaves of the transgenic plants. Changes in the distribution of H2O2 and in lesion formation were not reflected by changes in salicylic acid production. In contrast to the local response, the systemic response in upper noninoculated leaves of both CTA1 transgenic and control plants was similar. This suggests that increased cellular catalase activity influences local but not systemic response to TMV infection. PMID:12114558

  2. Arabidopsis plants perform arithmetic division to prevent starvation at night

    PubMed Central

    Scialdone, Antonio; Mugford, Sam T; Feike, Doreen; Skeffington, Alastair; Borrill, Philippa; Graf, Alexander; Smith, Alison M; Howard, Martin

    2013-01-01

    Photosynthetic starch reserves that accumulate in Arabidopsis leaves during the day decrease approximately linearly with time at night to support metabolism and growth. We find that the rate of decrease is adjusted to accommodate variation in the time of onset of darkness and starch content, such that reserves last almost precisely until dawn. Generation of these dynamics therefore requires an arithmetic division computation between the starch content and expected time to dawn. We introduce two novel chemical kinetic models capable of implementing analog arithmetic division. Predictions from the models are successfully tested in plants perturbed by a night-time light period or by mutations in starch degradation pathways. Our experiments indicate which components of the starch degradation apparatus may be important for appropriate arithmetic division. Our results are potentially relevant for any biological system dependent on a food reserve for survival over a predictable time period. DOI: http://dx.doi.org/10.7554/eLife.00669.001 PMID:23805380

  3. Toxicity and DNA damage in tobacco and potato plants growing on soil polluted with heavy metals.

    PubMed

    Gichner, Tomás; Patková, Zdenka; Száková, Jirina; Demnerová, Katerina

    2006-11-01

    Heterezygous tobacco (Nicotiana tabacum var. xanthi) and potato (Solanum tuberosum var. Korela) plants were cultivated on soil from the site Strimice which is highly polluted with heavy metals and on nonpolluted soil from the recreational site Jezerí, both in North Bohemia, Czech Republic. The total content, the content of bioavailable, easily mobile, and potentially mobile components of heavy metals (Cd, Cu, Pb, and Zn) in the tested soils, and the accumulation of these metals in the above-ground biomass and roots of tested plants were analyzed by flame atomic absorption spectrometry or flameless atomic absorption spectrometry. The average tobacco leaf area and potato plant height were significantly reduced in plants growing on the polluted soil. We have measured the DNA damage in nuclei of leaves of both plant species using the Comet assay. A small but significant increase in DNA damage was noted in plants growing on the polluted soil versus controls. As the tobacco and potato plants with increased DNA damage were severely injured (inhibited growth, distorted leaves), this increase may be associated with necrotic or apoptotic DNA fragmentation. No increase in the frequency of somatic mutation was detected in tobacco plants growing on the polluted soil. Thus, the polluted soil probably induced toxic but not genotoxic effects on tobacco and potato plants.

  4. Y3IP1, a Nucleus-Encoded Thylakoid Protein, Cooperates with the Plastid-Encoded Ycf3 Protein in Photosystem I Assembly of Tobacco and Arabidopsis[W][OA

    PubMed Central

    Albus, Christin A.; Ruf, Stephanie; Schöttler, Mark Aurel; Lein, Wolfgang; Kehr, Julia; Bock, Ralph

    2010-01-01

    The intricate assembly of photosystem I (PSI), a large multiprotein complex in the thylakoid membrane, depends on auxiliary protein factors. One of the essential assembly factors for PSI is encoded by ycf3 (hypothetical chloroplast reading frame number 3) in the chloroplast genome of algae and higher plants. To identify novel factors involved in PSI assembly, we constructed an epitope-tagged version of ycf3 from tobacco (Nicotiana tabacum) and introduced it into the tobacco chloroplast genome by genetic transformation. Immunoaffinity purification of Ycf3 complexes from the transplastomic plants identified a novel nucleus-encoded thylakoid protein, Y3IP1 (for Ycf3-interacting protein 1), that specifically interacts with the Ycf3 protein. Subsequent reverse genetics analysis of Y3IP1 function in tobacco and Arabidopsis thaliana revealed that knockdown of Y3IP1 leads to a specific deficiency in PSI but does not result in loss of Ycf3. Our data indicate that Y3IP1 represents a novel factor for PSI biogenesis that cooperates with the plastid genome-encoded Ycf3 in the assembly of stable PSI units in the thylakoid membrane. PMID:20807881

  5. Brassinosteroids Regulate Plant Growth through Distinct Signaling Pathways in Selaginella and Arabidopsis

    PubMed Central

    Cheon, Jinyeong; Fujioka, Shozo; Dilkes, Brian P.; Choe, Sunghwa

    2013-01-01

    Brassinosteroids (BRs) are growth-promoting steroid hormones that regulate diverse physiological processes in plants. Most BR biosynthetic enzymes belong to the cytochrome P450 (CYP) family. The gene encoding the ultimate step of BR biosynthesis in Arabidopsis likely evolved by gene duplication followed by functional specialization in a dicotyledonous plant-specific manner. To gain insight into the evolution of BRs, we performed a genomic reconstitution of Arabidopsis BR biosynthetic genes in an ancestral vascular plant, the lycophyte Selaginella moellendorffii. Selaginella contains four members of the CYP90 family that cluster together in the CYP85 clan. Similar to known BR biosynthetic genes, the Selaginella CYP90s exhibit eight or ten exons and Selaginella produces a putative BR biosynthetic intermediate. Therefore, we hypothesized that Selaginella CYP90 genes encode BR biosynthetic enzymes. In contrast to typical CYPs in Arabidopsis, Selaginella CYP90E2 and CYP90F1 do not possess amino-terminal signal peptides, suggesting that they do not localize to the endoplasmic reticulum. In addition, one of the three putative CYP reductases (CPRs) that is required for CYP enzyme function co-localized with CYP90E2 and CYP90F1. Treatments with a BR biosynthetic inhibitor, propiconazole, and epi-brassinolide resulted in greatly retarded and increased growth, respectively. This suggests that BRs promote growth in Selaginella, as they do in Arabidopsis. However, BR signaling occurs through different pathways than in Arabidopsis. A sequence homologous to the Arabidopsis BR receptor BRI1 was absent in Selaginella, but downstream components, including BIN2, BSU1, and BZR1, were present. Thus, the mechanism that initiates BR signaling in Selaginella seems to differ from that in Arabidopsis. Our findings suggest that the basic physiological roles of BRs as growth-promoting hormones are conserved in both lycophytes and Arabidopsis; however, different BR molecules and BRI1-based

  6. Brassinosteroids regulate plant growth through distinct signaling pathways in Selaginella and Arabidopsis.

    PubMed

    Cheon, Jinyeong; Fujioka, Shozo; Dilkes, Brian P; Choe, Sunghwa

    2013-01-01

    Brassinosteroids (BRs) are growth-promoting steroid hormones that regulate diverse physiological processes in plants. Most BR biosynthetic enzymes belong to the cytochrome P450 (CYP) family. The gene encoding the ultimate step of BR biosynthesis in Arabidopsis likely evolved by gene duplication followed by functional specialization in a dicotyledonous plant-specific manner. To gain insight into the evolution of BRs, we performed a genomic reconstitution of Arabidopsis BR biosynthetic genes in an ancestral vascular plant, the lycophyte Selaginella moellendorffii. Selaginella contains four members of the CYP90 family that cluster together in the CYP85 clan. Similar to known BR biosynthetic genes, the Selaginella CYP90s exhibit eight or ten exons and Selaginella produces a putative BR biosynthetic intermediate. Therefore, we hypothesized that Selaginella CYP90 genes encode BR biosynthetic enzymes. In contrast to typical CYPs in Arabidopsis, Selaginella CYP90E2 and CYP90F1 do not possess amino-terminal signal peptides, suggesting that they do not localize to the endoplasmic reticulum. In addition, one of the three putative CYP reductases (CPRs) that is required for CYP enzyme function co-localized with CYP90E2 and CYP90F1. Treatments with a BR biosynthetic inhibitor, propiconazole, and epi-brassinolide resulted in greatly retarded and increased growth, respectively. This suggests that BRs promote growth in Selaginella, as they do in Arabidopsis. However, BR signaling occurs through different pathways than in Arabidopsis. A sequence homologous to the Arabidopsis BR receptor BRI1 was absent in Selaginella, but downstream components, including BIN2, BSU1, and BZR1, were present. Thus, the mechanism that initiates BR signaling in Selaginella seems to differ from that in Arabidopsis. Our findings suggest that the basic physiological roles of BRs as growth-promoting hormones are conserved in both lycophytes and Arabidopsis; however, different BR molecules and BRI1-based

  7. A SIMPLE MODEL FOR THE UPTAKE, TRANSLOCATION, AND ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS

    EPA Science Inventory

    A simple mathematical model is being developed to describe the uptake, translocation, and accumulation of perchlorate in tobacco plants. The model defines a plant as a set of compartments, consisting of mass balance differential equations and plant-specific physiological paramet...

  8. A SIMPLE MODEL FOR THE UPTAKE, TRANSLOCATION, AND ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS

    EPA Science Inventory

    A simple mathematical model is being developed to describe the uptake, translocation, and accumulation of perchlorate in tobacco plants. The model defines a plant as a set of compartments, consisting of mass balance differential equations and plant-specific physiological paramet...

  9. Handling Arabidopsis plants: growth, preservation of seeds, transformation, and genetic crosses.

    PubMed

    Rivero, Luz; Scholl, Randy; Holomuzki, Nicholas; Crist, Deborah; Grotewold, Erich; Brkljacic, Jelena

    2014-01-01

    Growing healthy plants is essential for the advancement of Arabidopsis thaliana (Arabidopsis) research. Over the last 20 years, the Arabidopsis Biological Resource Center (ABRC) has collected and developed a series of best-practice protocols, some of which are presented in this chapter. Arabidopsis can be grown in a variety of locations, growth media, and environmental conditions. Most laboratory accessions and their mutant or transgenic derivatives flower after 4-5 weeks and set seeds after 7-8 weeks, under standard growth conditions (soil, long day, 23 ºC). Some mutant genotypes, natural accessions, and Arabidopsis relatives require strict control of growth conditions best provided by growth rooms, chambers, or incubators. Other lines can be grown in less-controlled greenhouse settings. Although the majority of lines can be grown in soil, certain experimental purposes require utilization of sterile solid or liquid growth media. These include the selection of primary transformants, identification of homozygous lethal individuals in a segregating population, or bulking of a large amount of plant material. The importance of controlling, observing, and recording growth conditions is emphasized and appropriate equipment required to perform monitoring of these conditions is listed. Proper conditions for seed harvesting and preservation, as well as seed quality control, are also described. Plant transformation and genetic crosses, two of the methods that revolutionized Arabidopsis genetics, are introduced as well.

  10. [Effects of biochar on the micro-ecology of tobacco-planting soil and physiology of flue-cured tobacco].

    PubMed

    Chen, Yi; Chen, Wei; Lin, Ye-chun; Cheng, Jian-zhong; Pan, Wen-jie

    2015-12-01

    Biochar is one of the research hotspots in the field of the agroforestry waste utilization. A field experiment was carried out to investigate the effects of different amounts of tobacco stem biochar (0, 1, 10, 50 t · hm⁻²) on soil micro-ecology and physiological properties of flue-cured tobacco. The results showed that soil water content (SWC) increased at all tobacco growth stages as the amounts of biochar applications increased. There were significant differences of SWC between the treatment of 50 t · hm⁻² and other treatments at the period of tobacco vigorous growth. As the application of biochar increased, the total soil porosity and capillary porosity increased, while soil bacteria, actinomyces, fungi amount increased firstly and then decreased. The amount of soil bacteria, actinomyces, fungi reached the maximum at the treatment of 10 t · hm⁻². Soil respiration rate (SRR) at earlier stage increased with the increase of biochar application. Compared with the control, SSR under biochar treatments increased by 7.9%-36.9%, and there were significant differences of SRR between high biochar application treatments (50 t · hm⁻² and 10 t · hm⁻²) and the control. Biochar improved leaf water potential, carotenoid and chlorophyll contents. Meanwhile, the dry mass of root, shoot and total dry mass under biochar application were higher than that of the control. These results indicated that the biochar played active roles in improving tobacco-planting soil micro-ecology and regulating physiological properties of flue-cured tobacco.

  11. Overexpression of several Arabidopsis histone genes increases Agrobacterium-medicated transformation and transgene expression in plants

    USDA-ARS?s Scientific Manuscript database

    The Arabidopsis histone H2A-1 is important for Agrobacterium-mediated plant transformation. Mutation of HTA1, the gene encoding histone H2A-1, in the rat5 mutant results in decreased T-(transferred) DNA integration into the plant genome, whereas over-expression of HTA1 increases transformation freq...

  12. Natural genetic variation in Arabidopsis for responsiveness to plant growth-promoting rhizobacteria.

    PubMed

    Wintermans, Paul C A; Bakker, Peter A H M; Pieterse, Corné M J

    2016-04-01

    The plant growth-promoting rhizobacterium (PGPR) Pseudomonas simiae WCS417r stimulates lateral root formation and increases shoot growth in Arabidopsis thaliana (Arabidopsis). These plant growth-stimulating effects are partly caused by volatile organic compounds (VOCs) produced by the bacterium. Here, we performed a genome-wide association (GWA) study on natural genetic variation in Arabidopsis for the ability to profit from rhizobacteria-mediated plant growth-promotion. To this end, 302 Arabidopsis accessions were tested for root architecture characteristics and shoot fresh weight in response to exposure to WCS417r. Although virtually all Arabidopsis accessions tested responded positively to WCS417r, there was a large variation between accessions in the increase in shoot fresh weight, the extra number of lateral roots formed, and the effect on primary root length. Correlation analyses revealed that the bacterially-mediated increase in shoot fresh weight is related to alterations in root architecture. GWA mapping for WCS417r-stimulated changes in root and shoot growth characteristics revealed 10 genetic loci highly associated with the responsiveness of Arabidopsis to the plant growth-promoting activity of WCS417r. Several of the underlying candidate genes have been implicated in important plant growth-related processes. These results demonstrate that plants possess natural genetic variation for the capacity to profit from the plant growth-promoting function of a beneficial rhizobacterium in their rhizosphere. This knowledge is a promising starting point for sustainable breeding strategies for future crops that are better able to maximize profitable functions from their root microbiome.

  13. Arabidopsis LOS5/ABA3 overexpression in transgenic tobacco (Nicotiana tabacum cv. Xanthi-nc) results in enhanced drought tolerance.

    PubMed

    Yue, Yuesen; Zhang, Mingcai; Zhang, Jiachang; Duan, Liusheng; Li, Zhaohu

    2011-10-01

    Drought is a major environmental stress factor that affects growth and development of plants. Abscisic acid (ABA), osmotically active compounds, and synthesis of specific proteins, such as proteins that scavenge oxygen radicals, are crucial for plants to adapt to water deficit. LOS5/ABA3 (LOS5) encodes molybdenum-cofactor sulfurase, which is a key regulator of ABA biosynthesis. We overexpressed LOS5 in tobacco using Agrobacterium-mediated transformation. Detached leaves of LOS5-overexpressing seedlings showed lower transpirational water loss than that of nontransgenic seedlings in the same period under normal conditions. When subjected to water-deficit stress, transgenic plants showed less wilting, maintained higher water content and better cellular membrane integrity, accumulated higher quantities of ABA and proline, and exhibited higher activities of antioxidant enzymes, i.e., superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, as compared with control plants. Furthermore, LOS5-overexpressing plants treated with 30% polyethylene glycol showed similar performance in cellular membrane protection, ABA and proline accumulation, and activities of catalase and peroxidase to those under drought stress. Thus, overexpression of LOS5 in transgenic tobacco can enhance drought tolerance.

  14. The application of Arabidopsis thaliana in studying tripartite interactions among plants, beneficial fungal endophytes and biotrophic plant-parasitic nematodes.

    PubMed

    Martinuz, Alfonso; Zewdu, Getaneh; Ludwig, Nicole; Grundler, Florian; Sikora, Richard A; Schouten, Alexander

    2015-04-01

    The research demonstrated that Arabidopsis can be used as a model system for studying plant-nematode-endophyte tripartite interactions; thus, opening new possibilities for further characterizing the molecular mechanisms behind these interactions. Arabidopsis has been established as an important model system for studying plant biology and plant-microbe interactions. We show that this plant can also be used for studying the tripartite interactions among plants, the root-knot nematode Meloidogyne incognita and a beneficial endophytic isolate of Fusarium oxysporum, strain Fo162. In various plant species, Fo162 can systemically reduce M. incognita infection development and fecundity. Here it is shown that Fo162 can also colonize A. thaliana roots without causing disease symptoms, thus behaving as a typical endophyte. As observed for other plants, this endophyte could not migrate from the roots into the shoots and leaves. Direct inoculation of the leaves also did not result in colonization of the plant. A significant increase in plant fresh weight, root length and average root diameter was observed, suggesting the promotion of plant growth by the endophyte. The inoculation of A. thaliana with F. oxysporum strain Fo162 also resulted in a significant reduction in the number of M. incognita juveniles infecting the roots and ultimately the number of galls produced. This was also observed in a split-root experiment, in which the endophyte and nematode were spatially separated. The usefulness of Arabidopsis opens new possibilities for further dissecting complex tripartite interactions at the molecular and biochemical level.

  15. Chloroplast-targeted bacterial RecA proteins confer tolerance to chloroplast DNA damage by methyl viologen or UV-C radiation in tobacco (Nicotiana tabacum) plants.

    PubMed

    Jeon, Hyesung; Jin, Yong-Mei; Choi, Mi Hwa; Lee, Hyeyun; Kim, Minkyun

    2013-02-01

    The nature and importance of the DNA repair system in the chloroplasts of higher plants under oxidative stress or UV radiation-induced genotoxicity was investigated via gain-of-functional approaches exploiting bacterial RecAs. For this purpose, transgenic tobacco (Nicotiana tabacum) plants and cell suspensions overexpressing Escherichia coli or Pseudomonas aeruginosa RecA fused to a chloroplast-targeting transit peptide were first produced. The transgenic tobacco plants maintained higher amounts of chloroplast DNA compared with wild-type (WT) upon treatments with methyl viologen (MV), a herbicide that generates reactive oxygen species (ROS) in chloroplasts. Consistent with these results, the transgenic tobacco leaves showed less bleaching than WT following MV exposure. Similarly, the MV-treated transgenic Arabidopsis plants overexpressing the chloroplast RecA homologue RECA1 showed weak bleaching, while the recA1 mutant showed opposite results upon MV treatment. In addition, when exposed to UV-C radiation, the dark-grown E. coli RecA-overexpressing transgenic tobacco cell suspensions, but not their WT counterparts, resumed growth and greening after the recovery period under light conditions. Measurements of UV radiation-induced chloroplast DNA damage using DraI assays (Harlow et al. 1994) with the chloroplast rbcL DNA probe and quantitative PCR analyses showed that the transgenic cell suspensions better repaired their UV-C radiation-induced chloroplast DNA lesions compared with WT. Taken all together, it was concluded that RecA-overexpressing transgenic plants are endowed with an increased chloroplast DNA maintenance capacity and enhanced repair activities, and consequently have a higher survival tolerance to genotoxic stresses. These observations are made possible by the functional compatibility of the bacterial RecAs in chloroplasts. Copyright © Physiologia Plantarum 2012.

  16. [Transgenic tobacco plants with ribosome inactivating protein gene cassin from Cassia occidentalis and their resistance to tobacco mosaic virus].

    PubMed

    Ruan, Xiao-Lei; Liu, Li-Fang; Li, Hua-Ping

    2007-12-01

    Cassin, the new gene of ribosome-inactivating protein (RIP) isolated from Cassia occidentalis, was inserted into expression vector pBI121 to produce plant expression vector pBI121-cassin (Figs.1, 2). pBI121-cassin was introduced into tobacco cultivar 'K326' by the Agrobacteriurm tumefaciens transformation method and more than 100 independent transformants were obtained. Southern blot hybridization analysis showed that a single gene locus was inserted into the chromosome of the transgenic tobacco lines (Fig.5) and PCR analysis of segregation population of progeny indicated that the inheritance of transgene was dominant in transgenic lines (Fig.4, Table 1). Results of RT-PCR and Northern blot hybridization analysis showed that transgene could be transcribed correctly (Figs.5, 6) . Three self-pollination lines of transgenic T(1) and T(2) were challenged with TMV at different concentration titers by mechanical inoculation. The transgenic lines exhibited different levels of resistance to TMV with the nontransgenic plants. After both titers of TMV concentration were inoculated, transgenic lines were considered as the highly resistant type with a delay of 4-13 d in development of symptoms and 10%-25% of test plants were infected, while nontransgenic control plants were susceptible typical symptoms on the newly emerged leaves (Table 2). One T(2) line, T(2)-8-2-1, was regarded as an immune type because it did not show any symptoms during 70 d and all plants were shown to be virus free by ELISA tests.

  17. Over-expression of TaEXPB23, a wheat expansin gene, improves oxidative stress tolerance in transgenic tobacco plants.

    PubMed

    Han, Yangyang; Chen, Yanhui; Yin, Suhong; Zhang, Meng; Wang, Wei

    2015-01-15

    Expansins are cell wall proteins inducing cell wall loosening and participate in all plant growth and development processes which are associated with cell wall modifications. Here, TaEXPB23, a wheat expansin gene, was investigated and the tolerance to oxidative stress was strongly enhanced in over-expression tobacco plants. Our results revealed that over-expressing TaEXPB23 influenced the activity of antioxidant enzymes: in particular, the activity of the cell wall-bound peroxidase. The enhanced tolerance to oxidative stress and increased cell wall-bound peroxidase activity were partly inhibited by an anti-expansin antibody. The Arabidopsis expansin mutant atexpb2 showed reduced cell wall-bound peroxidase activity and decreased oxidative stress tolerance. In addition, atexpb2 exhibited lower chlorophyll contents and the germination rate compared to wild type (WT). Taken together, these results provided a new insight on the role of expansin proteins in plant stress tolerance by cell wall bound peroxidase. Copyright © 2014 Elsevier GmbH. All rights reserved.

  18. Disarming the jasmonate-dependent plant defense makes nonhost Arabidopsis plants accessible to the American serpentine leafminer.

    PubMed

    Abe, Hiroshi; Tateishi, Ken; Seo, Shigemi; Kugimiya, Soichi; Hirai, Masami Yokota; Sawada, Yuji; Murata, Yoshiyuki; Yara, Kaori; Shimoda, Takeshi; Kobayashi, Masatomo

    2013-11-01

    Here, we analyzed the interaction between Arabidopsis (Arabidopsis thaliana) and the American serpentine leafminer (Liriomyza trifolii), an important and intractable herbivore of many cultivated plants. We examined the role of the immunity-related plant hormone jasmonate (JA) in the plant response and resistance to leafminer feeding to determine whether JA affects host suitability for leafminers. The expression of marker genes for the JA-dependent plant defense was induced by leafminer feeding on Arabidopsis wild-type plants. Analyses of JA-insensitive coi1-1 mutants suggested the importance of JA in the plant response to leafminer feeding. The JA content of wild-type plants significantly increased after leafminer feeding. Moreover, coi1-1 mutants showed lower feeding resistance against leafminer attack than did wild-type plants. The number of feeding scars caused by inoculated adult leafminers in JA-insensitive coi1-1 mutants was higher than that in wild-type plants. In addition, adults of the following generation appeared only from coi1-1 mutants and not from wild-type plants, suggesting that the loss of the JA-dependent plant defense converted nonhost plants to accessible host plants. Interestingly, the glucosinolate-myrosinase defense system may play at most a minor role in this conversion, indicating that this major antiherbivore defense of Brassica species plants probably does not have a major function in plant resistance to leafminer. Application of JA to wild-type plants before leafminer feeding enhanced feeding resistance in Chinese cabbage (Brassica rapa), tomato (Solanum lycopersicum), and garland chrysanthemum (Chrysanthemum coronarium). Our results indicate that JA plays an important role in the plant response and resistance to leafminers and, in so doing, affects host plant suitability for leafminers.

  19. Disarming the Jasmonate-Dependent Plant Defense Makes Nonhost Arabidopsis Plants Accessible to the American Serpentine Leafminer1

    PubMed Central

    Abe, Hiroshi; Tateishi, Ken; Seo, Shigemi; Kugimiya, Soichi; Hirai, Masami Yokota; Sawada, Yuji; Murata, Yoshiyuki; Yara, Kaori; Shimoda, Takeshi; Kobayashi, Masatomo

    2013-01-01

    Here, we analyzed the interaction between Arabidopsis (Arabidopsis thaliana) and the American serpentine leafminer (Liriomyza trifolii), an important and intractable herbivore of many cultivated plants. We examined the role of the immunity-related plant hormone jasmonate (JA) in the plant response and resistance to leafminer feeding to determine whether JA affects host suitability for leafminers. The expression of marker genes for the JA-dependent plant defense was induced by leafminer feeding on Arabidopsis wild-type plants. Analyses of JA-insensitive coi1-1 mutants suggested the importance of JA in the plant response to leafminer feeding. The JA content of wild-type plants significantly increased after leafminer feeding. Moreover, coi1-1 mutants showed lower feeding resistance against leafminer attack than did wild-type plants. The number of feeding scars caused by inoculated adult leafminers in JA-insensitive coi1-1 mutants was higher than that in wild-type plants. In addition, adults of the following generation appeared only from coi1-1 mutants and not from wild-type plants, suggesting that the loss of the JA-dependent plant defense converted nonhost plants to accessible host plants. Interestingly, the glucosinolate-myrosinase defense system may play at most a minor role in this conversion, indicating that this major antiherbivore defense of Brassica species plants probably does not have a major function in plant resistance to leafminer. Application of JA to wild-type plants before leafminer feeding enhanced feeding resistance in Chinese cabbage (Brassica rapa), tomato (Solanum lycopersicum), and garland chrysanthemum (Chrysanthemum coronarium). Our results indicate that JA plays an important role in the plant response and resistance to leafminers and, in so doing, affects host plant suitability for leafminers. PMID:24022267

  20. Endosome-Associated CRT1 Functions Early in Resistance Gene–Mediated Defense Signaling in Arabidopsis and Tobacco[W

    PubMed Central

    Kang, Hong-Gu; Oh, Chang-Sik; Sato, Masanao; Katagiri, Fumiaki; Glazebrook, Jane; Takahashi, Hideki; Kachroo, Pradeep; Martin, Gregory B.; Klessig, Daniel F.

    2010-01-01

    Resistance gene–mediated immunity confers protection against pathogen infection in a wide range of plants. A genetic screen for Arabidopsis thaliana mutants compromised for recognition of turnip crinkle virus previously identified CRT1, a member of the GHKL ATPase/kinase superfamily. Here, we demonstrate that CRT1 interacts with various resistance proteins from different structural classes, and this interaction is disrupted when these resistance proteins are activated. The Arabidopsis mutant crt1-2 crh1-1, which lacks CRT1 and its closest homolog, displayed compromised resistance to avirulent Pseudomonas syringae and Hyaloperonospora arabidopsidis. Additionally, resistance-associated hypersensitive cell death was suppressed in Nicotiana benthamiana silenced for expression of CRT1 homolog(s). Thus, CRT1 appears to be a general factor for resistance gene–mediated immunity. Since elevation of cytosolic calcium triggered by avirulent P. syringae was compromised in crt1-2 crh1-1 plants, but cell death triggered by Nt MEK2DD was unaffected in CRT1-silenced N. benthamiana, CRT1 likely functions at an early step in this pathway. Genome-wide transcriptome analysis led to identification of CRT1-Associated genes, many of which are associated with transport processes, responses to (a)biotic stress, and the endomembrane system. Confocal microscopy and subcellular fractionation revealed that CRT1 localizes to endosome-like vesicles, suggesting a key process in resistance protein activation/signaling occurs in this subcellular compartment. PMID:20332379

  1. Endosome-associated CRT1 functions early in resistance gene-mediated defense signaling in Arabidopsis and tobacco.

    PubMed

    Kang, Hong-Gu; Oh, Chang-Sik; Sato, Masanao; Katagiri, Fumiaki; Glazebrook, Jane; Takahashi, Hideki; Kachroo, Pradeep; Martin, Gregory B; Klessig, Daniel F

    2010-03-01

    Resistance gene-mediated immunity confers protection against pathogen infection in a wide range of plants. A genetic screen for Arabidopsis thaliana mutants compromised for recognition of turnip crinkle virus previously identified CRT1, a member of the GHKL ATPase/kinase superfamily. Here, we demonstrate that CRT1 interacts with various resistance proteins from different structural classes, and this interaction is disrupted when these resistance proteins are activated. The Arabidopsis mutant crt1-2 crh1-1, which lacks CRT1 and its closest homolog, displayed compromised resistance to avirulent Pseudomonas syringae and Hyaloperonospora arabidopsidis. Additionally, resistance-associated hypersensitive cell death was suppressed in Nicotiana benthamiana silenced for expression of CRT1 homolog(s). Thus, CRT1 appears to be a general factor for resistance gene-mediated immunity. Since elevation of cytosolic calcium triggered by avirulent P. syringae was compromised in crt1-2 crh1-1 plants, but cell death triggered by Nt MEK2(DD) was unaffected in CRT1-silenced N. benthamiana, CRT1 likely functions at an early step in this pathway. Genome-wide transcriptome analysis led to identification of CRT1-Associated genes, many of which are associated with transport processes, responses to (a)biotic stress, and the endomembrane system. Confocal microscopy and subcellular fractionation revealed that CRT1 localizes to endosome-like vesicles, suggesting a key process in resistance protein activation/signaling occurs in this subcellular compartment.

  2. Loss of Inositol Phosphorylceramide Sphingolipid Mannosylation Induces Plant Immune Responses and Reduces Cellulose Content in Arabidopsis[OPEN

    PubMed Central

    Ishikawa, Toshiki; Rennie, Emilie A.; Lao, Jeemeng; Yan, Jingwei; Tsai, Alex Yi-Lin; Baidoo, Edward E.K.; Demura, Taku; Kawai-Yamada, Maki

    2016-01-01

    Glycosylinositol phosphorylceramides (GIPCs) are a class of glycosylated sphingolipids found in plants, fungi, and protozoa. These lipids are abundant in the plant plasma membrane, forming ∼25% of total plasma membrane lipids. Little is known about the function of the glycosylated headgroup, but two recent studies have indicated that they play a key role in plant signaling and defense. Here, we show that a member of glycosyltransferase family 64, previously named ECTOPICALLY PARTING CELLS1, is likely a Golgi-localized GIPC-specific mannosyl-transferase, which we renamed GIPC MANNOSYL-TRANSFERASE1 (GMT1). Sphingolipid analysis revealed that the Arabidopsis thaliana gmt1 mutant almost completely lacks mannose-carrying GIPCs. Heterologous expression of GMT1 in Saccharomyces cerevisiae and tobacco (Nicotiana tabacum) cv Bright Yellow 2 resulted in the production of non-native mannosylated GIPCs. gmt1 displays a severe dwarfed phenotype and a constitutive hypersensitive response characterized by elevated salicylic acid and hydrogen peroxide levels, similar to that we previously reported for the Golgi-localized, GIPC-specific, GDP-Man transporter GONST1 (Mortimer et al., 2013). Unexpectedly, we show that gmt1 cell walls have a reduction in cellulose content, although other matrix polysaccharides are unchanged. PMID:27895225

  3. Enhanced V-ATPase activity contributes to the improved salt tolerance of transgenic tobacco plants overexpressing vacuolar Na(+)/H (+) antiporter AtNHX1.

    PubMed

    Zhou, Shufeng; Zhang, Zhiming; Tang, Qilin; Lan, Hai; Li, Yinxin; Luo, Ping

    2011-02-01

    AtNHX1, a vacuolar Na(+)/H(+) antiporter gene from Arabidopsis thaliana, was introduced into tobacco genome via Agrobacterium tumefaciens-mediated transformation to evaluate the role of vacuolar energy providers in plants salt stress response. Compared to the wild-type plants, over-expression of AtNHX1 increased salt tolerance in the transgenic tobacco plants, allowing higher germination rates of seeds and successful seedling establishment in the presence of toxic concentrations of NaCl. More importantly, the induced Na(+)/H(+) exchange activity in the transgenic plants was closely correlated to the enhanced activity of vacuolar H(+)-ATPase (V-ATPase) when exposed to 200 mM NaCl. In addition, inhibition of V-ATPase activity led to the malfunction of Na(+)/H(+) exchange activity, placing V-ATPase as the dominant energy provider for the vacuolar Na(+)/H(+) antiporter AtNHX1. V-ATPase and vacuolar Na(+)/H(+) antiporter thus function in an additive or synergistic way. Simultaneous overexpression of V-ATPase and vacuolar Na(+)/H(+) antiporter might be appropriate for producing plants with a higher salt tolerance ability.

  4. The Use of Arabidopsis to Study Interactions between Parasitic Angiosperms and Their Plant Hosts

    PubMed Central

    Goldwasser, Y.; Westwood, J. H.; Yoder, J. I.

    2002-01-01

    Parasitic plants invade host plants in order to rob them of water, minerals and nutrients. The consequences to the infected hosts can be debilitating and some of the world's most pernicious agricultural weeds are parasitic. Parasitic genera of the Scrophulariaceae and Orobanchaceae directly invade roots of neighboring plants via underground structures called haustoria. The mechanisms by which these parasites identify and associate with host plants present unsurpassed opportunities for studying chemical signaling in plant-plant interactions. Seeds of some parasites require specific host factors for efficient germination, thereby insuring the availability of an appropriate host root prior to germination. A second set of signal molecules is required to induce haustorium development and the beginning of heterotrophy. Later stages in parasitism also require the presence of host factors, although these have not yet been well characterized. Arabidopsis is being used as a model host plant to identify genetic loci associated with stimulating parasite germination, haustorium development, and parasite support. Arabidopsis is also being employed to explore how host plants respond to parasite attack. Current methodologies and recent findings in Arabidopsis – parasitic plant interactions will be discussed. PMID:22303205

  5. 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.

  6. 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.

  7. Plant-growth promoting effect of newly isolated rhizobacteria varies between two Arabidopsis ecotypes

    PubMed Central

    Schwachtje, Jens; Karojet, Silke; Kunz, Sabine; Brouwer, Stephan; van Dongen, Joost T.

    2012-01-01

    Various rhizobacteria are known for their beneficial effects on plants, i. e. promotion of growth and induction of systemic resistance against pathogens. These bacteria are categorized as plant growth promoting rhizobacteria (PGPR) and are associated with plant roots. Knowledge of the underlying mechanisms of plant growth promotion in vivo is still very limited, but interference of bacteria with plant hormone metabolism is suggested to play a major role. To obtain new growth promoting bacteria, we started a quest for rhizobacteria that are naturally associated to Arabidopsis thaliana. A suite of native root-associated bacteria were isolated from surface-sterilized roots of the Arabidopsis ecotype Gol-1 derived from a field site near Golm (Berlin area, Germany). We found several Pseudomonas and a Microbacterium species and tested these for growth promotion effects on the Arabidopsis ecotypes Gol-1 and Col-0, and for growth-promotion associated traits, such as auxin production, ACC deaminase activity and phosphate solubilization capacity. We showed that two of the bacteria strains promote plant growth with respect to rosette diameter, stalk length and accelerate development and that the effects were greater when bacteria were applied to Col-0 compared with Gol-1. Furthermore, the capability of promoting growth was not explained by the tested metabolic properties of the bacteria, suggesting that further bacterial traits are required. The natural variation of growth effects, combined with the extensive transgenic approaches available for the model plant Arabidopsis, will build a valuable tool to augment our understanding of the molecular mechanisms involved in the natural Arabidopsis - PGPR association. PMID:22580689

  8. Plant-growth promoting effect of newly isolated rhizobacteria varies between two Arabidopsis ecotypes.

    PubMed

    Schwachtje, Jens; Karojet, Silke; Kunz, Sabine; Brouwer, Stephan; van Dongen, Joost T

    2012-06-01

    Various rhizobacteria are known for their beneficial effects on plants, i. e. promotion of growth and induction of systemic resistance against pathogens. These bacteria are categorized as plant growth promoting rhizobacteria (PGPR) and are associated with plant roots. Knowledge of the underlying mechanisms of plant growth promotion in vivo is still very limited, but interference of bacteria with plant hormone metabolism is suggested to play a major role. To obtain new growth promoting bacteria, we started a quest for rhizobacteria that are naturally associated to Arabidopsis thaliana. A suite of native root-associated bacteria were isolated from surface-sterilized roots of the Arabidopsis ecotype Gol-1 derived from a field site near Golm (Berlin area, Germany). We found several Pseudomonas and a Microbacterium species and tested these for growth promotion effects on the Arabidopsis ecotypes Gol-1 and Col-0, and for growth-promotion associated traits, such as auxin production, ACC deaminase activity and phosphate solubilization capacity. We showed that two of the bacteria strains promote plant growth with respect to rosette diameter, stalk length and accelerate development and that the effects were greater when bacteria were applied to Col-0 compared with Gol-1. Furthermore, the capability of promoting growth was not explained by the tested metabolic properties of the bacteria, suggesting that further bacterial traits are required. The natural variation of growth effects, combined with the extensive transgenic approaches available for the model plant Arabidopsis, will build a valuable tool to augment our understanding of the molecular mechanisms involved in the natural Arabidopsis - PGPR association.

  9. F-box gene family is expanded in herbaceous annual plants Arabidopsis and rice relative to woody perennial plant Populus

    SciTech Connect

    Yang, Xiaohan; Kalluri, Udaya C; Jawdy, Sara; Gunter, Lee E; Yin, Tongming; Tschaplinski, Timothy J; Weston, David; Ranjan, Priya; Tuskan, Gerald A

    2008-01-01

    F-box proteins are generally responsible for substrate recognition in the Skp1-Cullin-F-box complexes that are involved in protein degradation via the ubiquitin-26S proteosome pathway. In plants, F-box genes influence a variety of biological processes such as leaf senescence, branching, self-incompatibility and responses to biotic and abiotic stresses. The number of F-box genes in Populus (~320) is less than half that found in Arabidopsis (~660) or rice (~680), even though the total number of genes in Populus is equivalent to that in rice and 1.5 times that in Arabidopsis. We performed comparative genomic analysis between the woody perennial plant Populus and the herbaceous annual plants Arabidopsis and rice in order to explicate the functional implications of this large gene family. Our analyses reveal interspecific differences in genomic distribution, orthologous relationship, intron evolution, protein domain structure and gene expression. The set of F-box genes shared by these three species appear to be involved in core biological processes essential for plant growth and development; lineage-specific differences primarily occurred because of an expansion of the F-box genes via tandem duplications in Arabidopsis and rice. The present study provides insights into the relationship between the structure and composition of the F-box gene family in herbaceous and woody species and their associated developmental and physiological features.

  10. Tomato plants ectopically expressing Arabidopsis CBF1 show enhanced resistance to water deficit stress.

    PubMed

    Hsieh, Tsai-Hung; Lee, Jent-turn; Charng, Yee-yung; Chan, Ming-Tsair

    2002-10-01

    A DNA cassette containing an Arabidopsis C repeat/dehydration-responsive element binding factor 1 (CBF1) cDNA and a nos terminator, driven by a cauliflower mosaic virus 35S promoter, was transformed into the tomato (Lycopersicon esculentum) genome. These transgenic tomato plants were more resistant to water deficit stress than the wild-type plants. The transgenic plants exhibited growth retardation by showing dwarf phenotype, and the fruit and seed numbers and fresh weight of the transgenic tomato plants were apparently less than those of the wild-type plants. Exogenous gibberellic acid treatment reversed the growth retardation and enhanced growth of transgenic tomato plants, but did not affect the level of water deficit resistance. The stomata of the transgenic CBF1 tomato plants closed more rapidly than the wild type after water deficit treatment with or without gibberellic acid pretreatment. The transgenic tomato plants contained higher levels of Pro than those of the wild-type plants under normal or water deficit conditions. Subtractive hybridization was used to isolate the responsive genes to heterologous CBF1 in transgenic tomato plants and the CAT1 (CATALASE1) was characterized. Catalase activity increased, and hydrogen peroxide concentration decreased in transgenic tomato plants compared with the wild-type plants with or without water deficit stress. These results indicated that the heterologous Arabidopsis CBF1 can confer water deficit resistance in transgenic tomato plants.

  11. Humans Have Antibodies against a Plant Virus: Evidence from Tobacco Mosaic Virus

    PubMed Central

    Liu, Ruolan; Vaishnav, Radhika A.; Roberts, Andrew M.; Friedland, Robert P.

    2013-01-01

    Tobacco mosaic virus (TMV), a widespread plant pathogen, is found in tobacco (including cigarettes and smokeless tobacco) as well as in many other plants. Plant viruses do not replicate or cause infection in humans or other mammals. This study was done to determine whether exposure to tobacco products induces an immune response to TMV in humans. Using a sandwich ELISA assay, we detected serum anti-TMV antibodies (IgG, IgG1, IgG3, IgG4, IgA, and IgM) in all subjects enrolled in the study (20 healthy smokers, 20 smokeless-tobacco users, and 20 non-smokers). Smokers had a higher level of serum anti-TMV IgG antibodies than non-smokers, while the serum level of anti-TMV IgA from smokeless tobacco users was lower than smokers and non-smokers. Using bioinformatics, we also found that the human protein TOMM40L (an outer mitochondrial membrane 40 homolog – like translocase) contains a strong homology of six contiguous amino acids to the TMV coat protein, and TOMM40L peptide exhibited cross-reactivity with anti-TMV antibodies. People who smoke cigarettes or other tobacco products experience a lower risk of developing Parkinson’s disease, but the mechanism by which this occurs is unclear. Our results showing molecular mimicry between TMV and human TOMM40L raise the question as to whether TMV has a potential role in smokers against Parkinson’s disease development. The potential mechanisms of molecular mimicry between plant viruses and human disease should be further explored. PMID:23573274

  12. Plant Formate Dehydrogenase

    SciTech Connect

    John Markwell

    2005-01-10

    The research in this study identified formate dehydrogenase, an enzyme that plays a metabolic role on the periphery of one-carbon metabolism, has an unusual localization in Arabidopsis thaliana and that the enzyme has an unusual kinetic plasticity. These properties make it possible that this enzyme could be engineered to attempt to engineer plants with an improved photosynthetic efficiency. We have produced transgenic Arabidopsis and tobacco plants with increased expression of the formate dehydrogenase enzyme to initiate further studies.

  13. Halomethane production in plants: Structure of the biosynthetic SAM-dependent halide methyltransferase from Arabidopsis thaliana**

    PubMed Central

    Schmidberger, Jason W.; James, Agata B.; Edwards, Robert; Naismith, James H.; O’Hagan, David

    2012-01-01

    A product structure of the halomethane producing enzyme in plants (Arabidopsis thaliana) is reported and a model for presentation of chloride/bromide ion to the methyl group of S-adenosyl-L-methionine (SAM) is presented to rationalise nucleophilic halide attack for halomethane production, gaseous natural products that are produced globally. PMID:20376845

  14. A rapid and efficient method to study the function of crop plant transporters in Arabidopsis.

    PubMed

    Wang, Xiangfeng; Zhong, Fudi; Woo, Cheuk Hang; Miao, Yansong; Grusak, Michael A; Zhang, Xiaobo; Tu, Jumin; Wong, Yum Shing; Jiang, Liwen

    2017-03-01

    Iron (Fe) is an essential micronutrient for humans. Fe deficiency disease is widespread and has led to extensive studies on the mechanisms of Fe uptake and storage, especially in staple food crops such as rice. However, studies of functionally related genes in rice and other crops are often time and space demanding. Here, we demonstrate that transgenic Arabidopsis suspension culture cells and Arabidopsis plants can be used as an efficient expression system for gain-of-function study of selected transporters, using Fe transporters as a proof-of-principle. The vacuolar membrane transporters OsVIT1 and OsVIT2 have been described to be important for iron sequestration, and disruption of these two genes leads to Fe accumulation in rice seeds. In this study, we have taken advantage of the fluorescent-tagged protein GFP-OsVIT1, which functionally complements the Fe hypersensitivity of ccc1 yeast mutant, to generate transgenic Arabidopsis suspension cell lines and plants. GFP-OsVIT1 was shown to localize on the vacuolar membrane using confocal microscopy and immunogold EM. More importantly, the Fe concentration, as well as the concentration of Zn, in the transgenic cell lines and plants were significantly increased compared to that in the WT. Taken together, our study shows that the heterologous expression of rice vacuolar membrane transporter OsVIT1 in Arabidopsis system is functional and effectively enhances iron accumulation, indicating an useful approach for studying other putative transporters of crop plants in this system.

  15. Expression of a functional human adenosine deaminase in transgenic tobacco plants.

    PubMed

    Singhabahu, Sanjeewa; George, John; Bringloe, David

    2013-06-01

    An inherited disorder, adenosine deaminase deficiency is a form of severe combined immunodeficiency, which is ultimately caused by an absence of adenosine deaminase (ADA), a key enzyme of the purine salvage pathway. The absence of ADA-activity in sufferers eventually results in a dysfunctional immune system due to the build-up of toxic metabolites. To date, this has been treated with mixed success, using PEG-ADA, made from purified bovine ADA coupled to polyethylene glycol. It is likely, however, that an enzyme replacement therapy protocol based on recombinant human ADA would be a more effective treatment for this disease. Therefore, as a preliminary step to produce biologically active human ADA in transgenic tobacco plants a human ADA cDNA has been inserted into a plant expression vector under the control of the CaMV 35S promoter and both human and TMV 5' UTR control regions. Plant vector expression constructs have been used to transform tobacco plants via Agrobacterium-mediated transformation. Genomic DNA, RNA and protein blot analyses have demonstrated the integration of the cDNA construct into the plant nuclear genome and the expression of recombinant ADA mRNA and protein in transgenic tobacco leaves. Western blot analysis has also revealed that human and recombinant ADA have a similar size of approximately 41 kDa. ADA-specific activities of between 0.001 and 0.003 units per mg total soluble protein were measured in crude extracts isolated from transformed tobacco plant leaves.

  16. Ectopic Overexpression of SsCBF1, a CRT/DRE-Binding Factor from the Nightshade Plant Solanum lycopersicoides, Confers Freezing and Salt Tolerance in Transgenic Arabidopsis

    PubMed Central

    Zhang, Lili; Li, Zhenjun; Li, Jingfu; Wang, Aoxue

    2013-01-01

    The C-repeat (CRT)/dehydration-responsive element (DRE) binding factor (CBF/DREB1) transcription factors play a key role in cold response. However, the detailed roles of many plant CBFs are far from fully understood. A CBF gene (SsCBF1) was isolated from the cold-hardy plant Solanum lycopersicoides. A subcellular localization study using GFP fusion protein indicated that SsCBF1 is localized in the nucleus. We delimited the SsCBF1 transcriptional activation domain to the C-terminal segment comprising amino acid residues 193–228 (SsCBF1193–228). The expression of SsCBF1 could be dramatically induced by cold, drought and high salinity. Transactivation assays in tobacco leaves revealed that SsCBF1 could specifically bind to the CRT cis-elements in vivo to activate the expression of downstream reporter genes. The ectopic overexpression of SsCBF1 conferred increased freezing and high-salinity tolerance and late flowering phenotype to transgenic Arabidopsis. RNA-sequencing data exhibited that a set of cold and salt stress responsive genes were up-regulated in transgenic Arabidopsis. Our results suggest that SsCBF1 behaves as a typical CBF to contribute to plant freezing tolerance. Increased resistance to high-salinity and late flowering phenotype derived from SsCBF1 OE lines lend more credence to the hypothesis that plant CBFs participate in diverse physiological and biochemical processes related to adverse conditions. PMID:23755095

  17. Fumaric acid: an overlooked form of fixed carbon in Arabidopsis and other plant species

    SciTech Connect

    Chia, D.W.; Yoder, T.J.; Reiter, W.D.; Gibson, S.I.

    2000-10-01

    Photoassimilates are used by plants for production of energy, as carbon skeletons and in transport of fixed carbon between different plant organs. Many studies have been devoted to characterizing the factors that. regulate photoassimilate concentrations in different plant species. Most studies examining photoassimilate concentrations in C{sub 3} plants have focused on analyzing starch and soluble sugars. However, work presented here demonstrates that a number of C{sub 3} plants, including the popular model organism Arabidopsis thaliana (L.) Heynh., and agriculturally important plants, such as soybean [Glycine ma (L.) Merr.], contain significant quantities of furnaric acid. In fact, furnaric acid can accumulate to levels of several mg per g fresh weight in A-abidopsis leaves, often exceeding starch and soluble sugar levels. Furnaric acid is a component of the tricarboxylic acid cycle and, like starch and soluble sugars, can be metabolized to yield energy and carbon skeletons for production of other compounds. Fumaric acid concentrations increase with plant age and light intensity in Arabidopsis leaves. Arabidopsis phloem exudates contain significant quantities of fumaric acid, raising the possibility that fumaric acid may function in carbon transport.

  18. Synergistic effects of 2A-mediated polyproteins on the production of lignocellulose degradation enzymes in tobacco plants

    PubMed Central

    Bae, Hyeun-Jong

    2012-01-01

    Cost-effective bioethanol production requires a supply of various low-cost enzymes that can hydrolyse lignocellulosic materials consisting of multiple polymers. Because plant-based enzyme expression systems offer low-cost and large-scale production, this study simultaneously expressed β-glucosidase (BglB), xylanase (XylII), exoglucanase (E3), and endoglucanase (Cel5A) in tobacco plants, which were individually fused with chloroplast-targeting transit peptides and linked via the 2A self-cleaving oligopeptideex from foot-and-mouth disease virus (FMDV) as follows: [RsBglB-2A-RaCel5A], [RsXylII-2A-RaCel5A], and [RsE3-2A-RaCel5A]. The enzymes were targeted to chloroplasts in tobacco cells and their activities were confirmed. Similarly to the results of a transient assay using Arabidopsis thaliana protoplasts, when XylII was placed upstream of the 2A sequence, the [RsXylII-2A-RaCel5A] transgenic tobacco plant had a more positive influence on expression of the protein placed downstream. The [RsBglB-2A-RaCel5A] and [RsE3-2A-RaCel5A] transgenic lines displayed higher activities towards carboxylmethylcellulose (CMC) compared to those in the [RsXylII-2A-RaCel5A] transgenic line. This higher activity was attributable to the synergistic effects of the different cellulases used. The [RsBglB-2A-RaCel5A] lines exhibited greater efficiency (35–74% increase) of CMC hydrolysis when the exoglucanase CBHII was added. Among the various exoglucanases, E3 showed higher activity with the crude extract of the [RsBglB-2A-RaCel5A] transgenic line. Transgenic expression of 2A-mediated multiple enzymes induced synergistic effects and led to more efficient hydrolysis of lignocellulosic materials for bioethanol production. PMID:22798663

  19. Identification of moisture content in tobacco plant leaves using outlier sample eliminating algorithms and hyperspectral data.

    PubMed

    Sun, Jun; Zhou, Xin; Wu, Xiaohong; Zhang, Xiaodong; Li, Qinglin

    2016-02-26

    Fast identification of moisture content in tobacco plant leaves plays a key role in the tobacco cultivation industry and benefits the management of tobacco plant in the farm. In order to identify moisture content of tobacco plant leaves in a fast and nondestructive way, a method involving Mahalanobis distance coupled with Monte Carlo cross validation(MD-MCCV) was proposed to eliminate outlier sample in this study. The hyperspectral data of 200 tobacco plant leaf samples of 20 moisture gradients were obtained using FieldSpc(®) 3 spectrometer. Savitzky-Golay smoothing(SG), roughness penalty smoothing(RPS), kernel smoothing(KS) and median smoothing(MS) were used to preprocess the raw spectra. In addition, Mahalanobis distance(MD), Monte Carlo cross validation(MCCV) and Mahalanobis distance coupled to Monte Carlo cross validation(MD-MCCV) were applied to select the outlier sample of the raw spectrum and four smoothing preprocessing spectra. Successive projections algorithm (SPA) was used to extract the most influential wavelengths. Multiple Linear Regression (MLR) was applied to build the prediction models based on preprocessed spectra feature in characteristic wavelengths. The results showed that the preferably four prediction model were MD-MCCV-SG (Rp(2) = 0.8401 and RMSEP = 0.1355), MD-MCCV-RPS (Rp(2) = 0.8030 and RMSEP = 0.1274), MD-MCCV-KS (Rp(2) = 0.8117 and RMSEP = 0.1433), MD-MCCV-MS (Rp(2) = 0.9132 and RMSEP = 0.1162). MD-MCCV algorithm performed best among MD algorithm, MCCV algorithm and the method without sample pretreatment algorithm in the eliminating outlier sample from 20 different moisture gradients of tobacco plant leaves and MD-MCCV can be used to eliminate outlier sample in the spectral preprocessing. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. A systemic increase in the recombination frequency upon local infection of Arabidopsis thaliana plants with oilseed rape mosaic virus depends on plant age, the initial inoculum concentration and the time for virus replication.

    PubMed

    Yao, Youli; Kathiria, Palak; Kovalchuk, Igor

    2013-01-01

    In the past, we showed that local infection of tobacco leaves with either tobacco mosaic virus or oilseed rape mosaic virus (ORMV) resulted in a systemic increase in the homologous recombination frequency (HRF). Later on, we showed that a similar phenomenon occurs in Arabidopsis thaliana plants infected with ORMV. Here, we tested whether the time of removing the infected leaves as well as viral titer have any effect on the degree of changes in HRF in systemic tissues. An increase in HRF in systemic non-infected tissues was more pronounced when the infected leaves were detached from the infected plants at 60-96 h post-infection, rather than at earlier time. Next, we found that exposure to higher concentrations of inoculum was much more efficient in triggering an increase in HRF than exposure to lower concentrations. Finally, we showed that older plants exhibited a higher increase in HRF than younger plants. We found that an increase in genome instability in systemic tissues of locally infected plants depends on plant age, the concentration of initial inoculums and the time of viral replication.

  1. Uptake of Cadmium by Flue-Cured Tobacco Plants: Exploring Bioavailability

    NASA Astrophysics Data System (ADS)

    Holzer, I.; Robarge, W. P.; Vann, M. C.

    2015-12-01

    Scientific understanding of cadmium (Cd) cycling in North Carolina tobacco plants and soils has lagged, even as production of flue-cured tobacco remains an important part of the NC economy ($903 million in 2014). Cd is considered a tobacco contaminant. When tobacco is burned, Cd can exist as a fine aerosol and subsequent inhalation is linked to cancer. Tobacco root exudates enhance Cd uptake, even though the Cd concentration in NC soils is <0.1 mg/kg. Quantifying Cd concentrations in tobacco plants is crucial to understanding Cd bioavailability and implementing soil remediation efforts. The objective of this study was to develop a Cd mass balance for flue-cured tobacco grown under field conditions in NC. Whole plant samples were collected at transplanting and every 2 weeks thereafter until harvest. Individual plants were segregated into root, stalk and individual leaves (n = 15 whole plants/sampling date; composite samples were taken early in the growing season). After recording dry mass, samples were analyzed using ion-coupled plasma optical emission spectrometry or ion-coupled plasma mass spectrometry. Lower leaves contained the highest Cd concentrations ( 7-10 mg/kg). Leaves occupying the upper 50% of the plant had Cd concentrations of 2 mg/kg. Uptake rate was greatest from day 27 to 66 ( 21.5 μg Cd/day). Selective Cd uptake appears evident between day 27 and 43, but overall the relative rate of Cd uptake was similar to other trace metals and micronutrients. Cd distribution within the plants mirrored the distribution of calcium, a macronutrient. Of the 8 mg of soil extractable Cd (0.075 mg/kg) in the rooting zone, 15.0% (1203 μg) is removed by uptake. Of this 15%, 64.2% (772.2 μg) is exported at harvest, and 35.8% (430.8 μg; lower leaves, roots, stalks) is returned to the soil. This study must be replicated to account for seasonal and soil variations. These results do inform selection of tobacco strains that limit uptake of trace metals, particularly Cd.

  2. Glycan-binding F-box protein from Arabidopsis thaliana protects plants from Pseudomonas syringae infection.

    PubMed

    Stefanowicz, Karolina; Lannoo, Nausicaä; Zhao, Yafei; Eggermont, Lore; Van Hove, Jonas; Al Atalah, Bassam; Van Damme, Els J M

    2016-10-04

    A small group of F-box proteins consisting of a conserved F-box domain linked to a domain homologous to the glycan-binding protein has been identified within the genome of Arabidopsis thaliana. Previously, the so-called F-box-Nictaba protein, encoded by the gene At2g02360, was shown to be a functional lectin which binds N-acetyllactosamine structures. Here, we present a detailed qRT-PCR expression analysis of F-box-Nictaba in Arabidopsis plants upon different stresses and hormone treatments. Expression of the F-box-Nictaba gene was enhanced after plant treatment with salicylic acid and after plant infection with the virulent Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000). β-glucuronidase histochemical staining of transgenic Arabidopsis plants displayed preferential activity of the At2g02360 promoter in trichomes present on young rosette leaves. qRT-PCR analyses confirmed high expression of F-box-Nictaba in leaf trichomes. A. thaliana plants overexpressing the gene showed less disease symptoms after Pst DC3000 infection with reduced bacterial colonization compared to infected wild type and F-box-Nictaba knock-out plants. Our data show that the Arabidopsis F-box-Nictaba gene is a stress-inducible gene responsive to SA, bacterial infection and heat stress, and is involved in salicylic acid related plant defense responses. This knowledge enriched our understanding of the physiological importance of F-box-Nictaba, and can be used to create plants with better performance in changing environmental conditions.

  3. Magnitude of nighttime transpiration does not affect plant growth or nutrition in well-watered Arabidopsis.

    PubMed

    Christman, Mairgareth A; Donovan, Lisa A; Richards, James H

    2009-07-01

    Significant water loss occurs throughout the night via partially open stomata in many C(3) and C(4) plant species. Although apparently wasteful in terms of water use, nighttime transpiration (E(night)) is hypothesized to benefit plants by enhancing nutrient supply. We tested the hypothesis that plants with greater E(night) would have improved plant nutrient status and greater fitness, estimated as pre-bolting biomass, for Arabidopsis thaliana. Two very different levels of E(night) were generated in plants by exposing them to high vs low nighttime leaf-to-air vapor pressure deficits (VPD(leaf)) in controlled environment chambers. An assessment of responses of nighttime leaf conductance (g(night)) to VPD(leaf) indicated that E(night) differed by at least 80% between the treatments. This large difference in E(night), imposed over the entire vegetative growth phase of Arabidopsis, had no effect on leaf nutrient content (N, Ca, K) or pre-bolting rosette biomass. The lack of response to differences in E(night) held true for both a high and a low nitrogen (N) treatment, even though the low N treatment decreased leaf N and biomass by 40-60%. The N treatment had no effect on g(night). Thus, higher E(night) did not provide a nutrient or growth benefit to Arabidopsis, even when the plants were N-limited.

  4. Identification and Dynamics of Two Classes of Aurora-Like Kinases in Arabidopsis and Other PlantsW⃞

    PubMed Central

    Demidov, Dmitri; Van Damme, Daniël; Geelen, Danny; Blattner, Frank R.; Houben, Andreas

    2005-01-01

    Aurora-like kinases play key roles in chromosome segregation and cytokinesis in yeast, plant, and animal systems. Here, we characterize three Arabidopsis thaliana protein kinases, designated AtAurora1, AtAurora2, and AtAurora3, which share high amino acid identities with the Ser/Thr kinase domain of yeast Ipl1 and animal Auroras. Structure and expression of AtAurora1 and AtAurora2 suggest that these genes arose by a recent gene duplication, whereas the diversification of plant α and β Aurora kinases predates the origin of land plants. The transcripts and proteins of all three kinases are most abundant in tissues containing dividing cells. Intracellular localization of green fluorescent protein–tagged AtAuroras revealed an AtAurora-type specific association mainly with dynamic mitotic structures, such as microtubule spindles and centromeres, and with the emerging cell plate of dividing tobacco (Nicotiana tabacum) BY-2 cells. Immunolabeling using AtAurora antibodies yielded specific signals at the centromeres that are coincident with histone H3 that is phosphorylated at Ser position10 during mitosis. An in vitro kinase assay demonstrated that AtAurora1 preferentially phosphorylates histone H3 at Ser 10 but not at Ser 28 or Thr 3, 11, and 32. The phylogenetic analysis of available Aurora sequences from different eukaryotic origins suggests that, although a plant Aurora gene has been duplicated early in the evolution of plants, the paralogs nevertheless maintained a role in cell cycle–related signal transduction pathways. PMID:15722465

  5. Polyamine metabolic canalization in response to drought stress in Arabidopsis and the resurrection plant Craterostigma plantagineum

    PubMed Central

    Bartels, Dorothea; Koncz, Csaba; Altabella, Teresa

    2011-01-01

    In this work, we have studied the transcriptional profiles of polyamine biosynthetic genes and analyzed polyamine metabolic fluxes during a gradual drought acclimation response in Arabidopsis thaliana and the resurrection plant Craterostigma plantagineum. The analysis of free putrescine, spermidine and spermine titers in Arabidopsis arginine decarboxylase (adc1–3, adc2–3), spermidine synthase (spds1–2, spds2–3) and spermine synthase (spms-2) mutants during drought stress, combined with the quantitative expression of the entire polyamine biosynthetic pathway in the wild-type, has revealed a strong metabolic canalization of putrescine to spermine induced by drought. Such canalization requires spermidine synthase 1 (SPDS1) and spermine synthase (SPMS) activities and, intriguingly, does not lead to spermine accumulation but to a progressive reduction in spermidine and spermine pools in the wild-type. Our results suggest the participation of the polyamine back-conversion pathway during the drought stress response rather than the terminal catabolism of spermine. The putrescine to spermine canalization coupled to the spermine to putrescine back-conversion confers an effective polyamine recycling-loop during drought acclimation. Putrescine to spermine canalization has also been revealed in the desiccation tolerant plant C. plantagineum, which conversely to Arabidopsis, accumulates high spermine levels which associate with drought tolerance. Our results provide a new insight to the polyamine homeostasis mechanisms during drought stress acclimation in Arabidopsis and resurrection plants. PMID:21330782

  6. Polyamine metabolic canalization in response to drought stress in Arabidopsis and the resurrection plant Craterostigma plantagineum.

    PubMed

    Alcázar, Rubén; Bitrián, Marta; Bartels, Dorothea; Koncz, Csaba; Altabella, Teresa; Tiburcio, Antonio F

    2011-02-01

    In this work, we have studied the transcriptional profiles of polyamine biosynthetic genes and analyzed polyamine metabolic fluxes during a gradual drought acclimation response in Arabidopsis thaliana and the resurrection plant Craterostigma plantagineum. The analysis of free putrescine, spermidine and spermine titers in Arabidopsis arginine decarboxylase (adc1-3, adc2-3), spermidine synthase (spds1-2, spds2-3) and spermine synthase (spms-2) mutants during drought stress, combined with the quantitative expression of the entire polyamine biosynthetic pathway in the wild-type, has revealed a strong metabolic canalization of putrescine to spermine induced by drought. Such canalization requires spermidine synthase 1 (SPDS1) and spermine synthase (SPMS) activities and, intriguingly, does not lead to spermine accumulation but to a progressive reduction in spermidine and spermine pools in the wild-type. Our results suggest the participation of the polyamine back-conversion pathway during the drought stress response rather than the terminal catabolism of spermine. The putrescine to spermine canalization coupled to the spermine to putrescine back-conversion confers an effective polyamine recycling-loop during drought acclimation. Putrescine to spermine canalization has also been revealed in the desiccation tolerant plant C. plantagineum, which conversely to Arabidopsis, accumulates high spermine levels which associate with drought tolerance. Our results provide a new insight to the polyamine homeostasis mechanisms during drought stress acclimation in Arabidopsis and resurrection plants.

  7. Model plant systems in salinity and drought stress proteomics studies: a perspective on Arabidopsis and Sorghum.

    PubMed

    Ngara, R; Ndimba, B K

    2014-11-01

    More than a decade after the sequencing of its genome, Arabidopsis still stands as the epitome of a model system in plant biology. Arabidopsis proteomics has also taught us great lessons on different aspects of plant growth, development and physiology. Without doubt our understanding of basic principles of plant biology would not have been this advanced if it were not for knowledge gained using Arabidopsis as a model system. However, with the projections of global climate change and rapid population growth, it is high time we evaluate the applicability of this model system in studies aimed at understanding abiotic stress tolerance and adaptation, with a particular emphasis on maintaining yield under hot and dry environmental conditions. Because of the innate nature of sorghum's tolerance to drought and moderate tolerance to salinity stresses, we believe sorghum is the next logical model system in such studies amongst cereals. In this acute view, we highlight the importance of Arabidopsis as a model system, briefly discuss its potential limitations in drought and salt stress studies, and present our views on the potential usefulness of sorghum as a model system for cereals in drought and salinity stress proteomic studies.

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

    PubMed

    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.

  9. Ecogenomic survey of plant viruses infecting Tobacco by Next generation sequencing.

    PubMed

    Akinyemi, Ibukun A; Wang, Fang; Zhou, Benguo; Qi, Shuishui; Wu, Qingfa

    2016-11-04

    The invasion of plant by viruses cause major damage to plants and reduces crop yield and integrity. Devastating plant virus infection has been experienced at different times all over the world, which are attributed to different events of mutation, re-assortment and recombination occurring in the viruses. Strategies for proper virus management has been mostly limited to eradicating the vectors that spreads the plant viruses. However, development of prompt and effective diagnostic methods are required to monitor emerging and re-emerging diseases that may be symptomatic or asymptomatic in the plant as well as the genetic variation and evolution in the plant viruses. A survey of plant viruses infecting field-grown Tobacco crop was conducted in Anhui Province of China by the deep sequencing of sRNAs. Survey of plant viruses infecting Tobacco was carried based on 104 samples collected across the province. Nine different sRNA libraries was prepared and custom-made bioinformatics pipeline coupled with molecular techniques was developed to sequence, assemble and analyze the siRNAs for plant virus discovery. We also carried out phylogenetic and recombination analysis of the identified viruses. Twenty two isolates from eight different virus species including Cucumber mosaic virus, Potato virus Y, Tobacco mosaic virus, Tobacco vein banding Mosaic virus, Pepper mottle virus, Brassica yellow virus, Chilli venial mottle virus, Broad bean wilt virus 2 were identified in tobacco across the survey area. The near-complete genome sequence of the 22 new isolates were determined and analyzed. The isolates were grouped together with known strains in the phylogenetic tree. Molecular variation in the isolates indicated the conserved coding regions have majorly a nucleotide sequence identity of 80-94 % with previously identified isolates. Various events of recombination were discovered among some of the isolates indicating that two or more viruses or different isolates of one virus infect

  10. In Vitro Morphogenesis of Arabidopsis to Search for Novel Endophytic Fungi Modulating Plant Growth.

    PubMed

    Dovana, Francesco; Mucciarelli, Marco; Mascarello, Maurizio; Fusconi, Anna

    2015-01-01

    Fungal endophytes have shown to affect plant growth and to confer stress tolerance to the host; however, effects of endophytes isolated from water plants have been poorly investigated. In this study, fungi isolated from stems (stem-E) and roots (root-E) of Mentha aquatica L. (water mint) were identified, and their morphogenetic properties analysed on in vitro cultured Arabidopsis (L.) Heynh., 14 and 21 days after inoculation (DAI). Nineteen fungi were analysed and, based on ITS analysis, 17 isolates showed to be genetically distinct. The overall effect of water mint endophytes on Arabidopsis fresh (FW) and dry weight (DW) was neutral and positive, respectively, and the increased DW, mainly occurring 14 DAI, was possibly related to plant defence mechanism. Only three fungi increased both FW and DW of Arabidopsis at 14 and 21 DAI, thus behaving as plant growth promoting (PGP) fungi. E-treatment caused a reduction of root depth and primary root length in most cases and inhibition-to-promotion of root area and lateral root length, from 14 DAI. Only Phoma macrostoma, among the water mint PGP fungi, increased both root area and depth, 21 DAI. Root depth and area 14 DAI were shown to influence DWs, indicating that the extension of the root system, and thus nutrient uptake, was an important determinant of plant dry biomass. Reduction of Arabidopsis root depth occurred to a great extent when plants where treated with stem-E while root area decreased or increased under the effects of stem-E and root-E, respectively, pointing to an influence of the endophyte origin on root extension. M. aquatica and many other perennial hydrophytes have growing worldwide application in water pollution remediation. The present study provided a model for directed screening of endophytes able to modulate plant growth in the perspective of future field applications of these fungi.

  11. In Vitro Morphogenesis of Arabidopsis to Search for Novel Endophytic Fungi Modulating Plant Growth

    PubMed Central

    Mascarello, Maurizio

    2015-01-01

    Fungal endophytes have shown to affect plant growth and to confer stress tolerance to the host; however, effects of endophytes isolated from water plants have been poorly investigated. In this study, fungi isolated from stems (stem-E) and roots (root-E) of Mentha aquatica L. (water mint) were identified, and their morphogenetic properties analysed on in vitro cultured Arabidopsis (L.) Heynh., 14 and 21 days after inoculation (DAI). Nineteen fungi were analysed and, based on ITS analysis, 17 isolates showed to be genetically distinct. The overall effect of water mint endophytes on Arabidopsis fresh (FW) and dry weight (DW) was neutral and positive, respectively, and the increased DW, mainly occurring 14 DAI, was possibly related to plant defence mechanism. Only three fungi increased both FW and DW of Arabidopsis at 14 and 21 DAI, thus behaving as plant growth promoting (PGP) fungi. E-treatment caused a reduction of root depth and primary root length in most cases and inhibition-to-promotion of root area and lateral root length, from 14 DAI. Only Phoma macrostoma, among the water mint PGP fungi, increased both root area and depth, 21 DAI. Root depth and area 14 DAI were shown to influence DWs, indicating that the extension of the root system, and thus nutrient uptake, was an important determinant of plant dry biomass. Reduction of Arabidopsis root depth occurred to a great extent when plants where treated with stem-E while root area decreased or increased under the effects of stem-E and root-E, respectively, pointing to an influence of the endophyte origin on root extension. M. aquatica and many other perennial hydrophytes have growing worldwide application in water pollution remediation. The present study provided a model for directed screening of endophytes able to modulate plant growth in the perspective of future field applications of these fungi. PMID:26641657

  12. Dataset of Arabidopsis plants that overexpress FT driven by a meristem-specific KNAT1 promoter.

    PubMed

    Duplat-Bermúdez, L; Ruiz-Medrano, R; Landsman, D; Mariño-Ramírez, L; Xoconostle-Cázares, B

    2016-09-01

    In this dataset we integrated figures comparing leaf number and rosette diameter in three Arabidopsis FT overexpressor lines (AtFTOE) driven by KNAT1 promoter, "A member of the KNOTTED class of homeodomain proteins encoded by the STM gene of Arabidopsis" [5], vs Wild Type (WT) Arabidopsis plats. Also, presented in the tables are some transcriptomic data obtained by RNA-seq Illumina HiSeq from rosette leaves of Arabidopsis plants of AtFTOE 2.1 line vs WT with accession numbers SRR2094583 and SRR2094587 for AtFTOE replicates 1-3 and AtWT for control replicates 1-2 respectively. Raw data of paired-end sequences are located in the public repository of the National Center for Biotechnology Information of the National Library of Medicine, National Institutes of Health, United States of America, Bethesda, MD, USA as Sequence Read Archive (SRA). Performed analyses of differential expression genes are visualized by Mapman and presented in figures. "Transcriptomic analysis of Arabidopsis overexpressing flowering locus T driven by a meristem-specific promoter that induces early flowering" [2], described the interpretation and discussion of the obtained data.

  13. Spectral reflectance, chlorophyll fluorescence and virological investigations of tobacco plants (Nicotiana tabacum L.) infected with Tobacco mosaic virus (TMV)

    NASA Astrophysics Data System (ADS)

    Krezhova, Dora; Hristova, Dimitrina; Iliev, Ilko; Yanev, Tony

    Application of multispectral remote sensing techniques to plant condition monitoring has been adopted for various purposes. Remote sensing is a reliable tool for detecting signs of vege-tation stress and diseases. Spectral reflectance and chlorophyll fluorescence are functions of tissue optical properties and biological status of the plants, and illumination conditions. The mean reflectance spectrum depends on the relative composition of all the pigments in the leaf including chlorophylls, carotenoids etc. Chlorophyll fluorescence results from the primary re-actions of photosynthesis and during the last decade it finds widening application as a means for revelation of stress and diseases. The changes in chlorophyll function take place before the alteration in chlorophyll content to occur so that changes in the fluorescence signal arise before any visible signs are apparent. The aim of our investigations was to study the development and spreading out of a viral infection on the leaves of two cultivars tobacco plants (Nicotiana tabacum L.) infected with Tobacco mosaic virus (TMV). We applied two remote sensing tech-niques (spectral reflectance and chlorophyll fluorescence measurements) for evaluation of the changes in the optical properties of the plants in accordance to their physiological status. The serological analyses via the Double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) were made with appropriate kits (Leowe, Germany) for quantitative assessment of the concentration of viruses in the plants. The tobacco plants were grown in green house under controlled conditions. The first cultivar Nevrocop 1146 is known as resistive to the TMV, i.e. it shows hypersensitive response. The second cultivar named Krumovgrad is normally sen-sitive to the TMV. At growth stage 4-6 expanded leaf, up to one leaf from 20 plants for each cultivar were inoculated with TMV. The leaves opposite to the infected ones formed the group of control (untreated) leaves. The

  14. Dynamic metabonomic responses of tobacco (Nicotiana tabacum) plants to salt stress.

    PubMed

    Zhang, Jingtao; Zhang, Yong; Du, Yuanyuan; Chen, Shiyun; Tang, Huiru

    2011-04-01

    Metabolic responses are important for plant adaptation to osmotic stresses. To understand the dosage and duration dependence of salinity effects on plant metabolisms, we analyzed the metabonome of tobacco plants and its dynamic responses to salt treatments using NMR spectroscopy in combination with multivariate data analysis. Our results showed that the tobacco metabonome was dominated by 40 metabolites including organic acids/bases, amino acids, carbohydrates and choline, pyrimidine, and purine metabolites. A dynamic trajectory was clearly observable for the tobacco metabonomic responses to the dosage of salinity. Short-term low-dose salt stress (50 mM NaCl, 1 day) caused metabolic shifts toward gluconeogenesis with depletion of pyrimidine and purine metabolites. Prolonged salinity with high-dose salt (500 mM NaCl) induced progressive accumulation of osmolytes, such as proline and myo-inositol, and changes in GABA shunt. Such treatments also promoted the shikimate-mediated secondary metabolisms with enhanced biosynthesis of aromatic amino acids. Therefore, salinity caused systems alterations in widespread metabolic networks involving transamination, TCA cycle, gluconeogenesis/glycolysis, glutamate-mediated proline biosynthesis, shikimate-mediated secondary metabolisms, and the metabolisms of choline, pyrimidine, and purine. These findings provided new insights for the tobacco metabolic adaptation to salinity and demonstrated the NMR-based metabonomics as a powerful approach for understanding the osmotic effects on plant biochemistry.

  15. Application of lipid extracts from Solidago canadensis to phytomonitoring of PCB126 in transgenic Arabidopsis plants.

    PubMed

    Shimazu, Sayuri; Ohta, Masaya; Ashida, Hitoshi

    2014-09-01

    The aim of this study is to elucidate the effect of lipid extracts from Solidago canadensis for phytomonitoring of polychlorinated biphenyl (PCB) 126 in the transgenic Arabidopsis plant XgD2V11-6 carrying the recombinant guinea pig (g) aryl hydrocarbon receptor (AhR)-mediated β-glucuronidase (GUS) reporter gene expression system. A lipid extract was prepared from S. canadensis and separated into simple lipid, glycolipid, and phospholipid fractions by silica gel column chromatography. Sterylglucoside (SG), monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), and glucosyl ceramide were found in the glycolipid fraction. When the transgenic Arabidopsis plants were treated with the glycolipid fraction together with PCB126, PCB126-induced GUS activity significantly increased in the whole plant. Moreover, S. canadensis-derived SG, MGDG, and DGDG also significantly increased PCB126-induced GUS activity. These results indicated that glycolipids in S. canadensis enhanced the sensitivity of this monitoring assay. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Delay of Disease Development in Transgenic Plants that Express the Tobacco Mosaic Virus Coat Protein Gene

    NASA Astrophysics Data System (ADS)

    Powell Abel, Patricia; Nelson, Richard S.; de, Barun; Hoffmann, Nancy; Rogers, Stephen G.; Fraley, Robert T.; Beachy, Roger N.

    1986-05-01

    A chimeric gene containing a cloned cDNA of the coat protein (CP) gene of tobacco mosaic virus (TMV) was introduced into tobacco cells on a Ti plasmid of Agrobacterium tumefaciens from which tumor inducing genes had been removed. Plants regenerated from transformed cells expressed TMV mRNA and CP as a nuclear trait. Seedlings from self-fertilized transgenic plants were inoculated with TMV and observed for development of disease symptoms. The seedlings that expressed the CP gene were delayed in symptom development and 10 to 60 percent of the transgenic plants failed to develop symptoms for the duration of the experiments. Increasing the concentration of TMV in the inoculum shortened the delay in appearance of symptoms. The results of these experiments indicate that plants can be genetically transformed for resistance to virus disease development.

  17. Characterization of virus-induced gene silencing in tobacco plants infected with apple latent spherical virus.

    PubMed

    Yaegashi, H; Yamatsuta, T; Takahashi, T; Li, C; Isogai, M; Kobori, T; Ohki, S; Yoshikawa, N

    2007-01-01

    Apple latent spherical virus (ALSV) expressing green fluorescent protein (GFP-ALSV) was used for analysis of virus-induced gene silencing (VIGS) in tobacco plants expressing GFP (GFP-tobacco). In GFP-tobacco inoculated with GFP-ALSV, small dark spots appeared on inoculated leaves at 5 days post-inoculation (dpi), then expanded, and finally covered the whole area of the leaves after 12 dpi. Most of the fluorescence of upper leaves above the 12th true leaf disappeared at 21 dpi. Thus, GFP-ALSV infection efficiently triggered VIGS of a transgene (GFP gene) in tobacco plants. Analysis of GFP-silenced leaves showed that viral RNAs and proteins accumulated in all leaves where most GFP mRNA had been degraded. The siRNAs derived from ALSV-RNAs were not detected in samples from which siRNA of GFP mRNA could be easily detected. Direct tissue blot analysis showed that the spread of GFP-ALSV always preceded the induction of VIGS in infected leaves of GFP-tobacco. GFP leaf patch tests using Nicotiana benthamiana line 16c showed that Vp20, one of the three capsid proteins, is a silencing suppressor which interferes with systemic silencing.

  18. Viral RNA trafficking is inhibited in replicase-mediated resistant transgenic tobacco plants.

    PubMed Central

    Nguyen, L; Lucas, W J; Ding, B; Zaitlin, M

    1996-01-01

    Transgenic tobacco (Nicotiana tabacum cv. Turkish Samsun NN) plants expressing a truncated replicase gene sequence from RNA-2 of strain Fny of cucumber mosaic virus (CMV) are resistant to systemic CMV disease. This is due to suppression of virus replication and cell-to-cell movement in the inoculated leaves of these plants. In this study, microinjection protocols were used to directly examine cell-to-cell trafficking of CMV viral RNA in these resistant plants. CMV RNA fluorescently labeled with the nucleotide-specific TOTO-1 iodide dye, when coinjected with unlabeled CMV 3a movement protein (MP), moved rapidly into the surrounding mesophyll cells in mature tobacco leaves of vector control and untransformed plants. Such trafficking required the presence of functional CMV 3a MP. In contrast, coinjection of CMV 3a MP and CMV TOTO-RNA failed to move in transgenic resistant plants expressing the CMV truncated replicase gene. Furthermore, coinjection of 9.4-kDa fluorescein-conjugated dextran (F-dextran) along with unlabeled CMV 3a MP resulted in cell-to-cell movement of the F-dextran in control plants, but not in the transgenic plants. Similar results were obtained with viral RNA when the 30-kDa MP of tobacco mosaic virus (TMV) was coinjected with TMV TOTO-RNA into replicase-resistant transgenic tobacco expressing the 54-kDa gene sequence of TMV. However, in these transgenic plants, the TMV-MP was still capable of mediating cell-to-cell movement of itself and the 9.4-kDa F-dextran. These results indicate that an inhibition of cell-to-cell viral RNA trafficking is correlated with replicase-mediated resistance. This raises the possibility that the RNA-2 product is potentially involved in the regulation of cell-to-cell movement of viral infectious material during CMV replication. PMID:8901636

  19. 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

  20. The importance of Arabidopsis glutathione peroxidase 8 for protecting Arabidopsis plant and E. coli cells against oxidative stress

    PubMed Central

    Gaber, Ahmed

    2014-01-01

    Glutathione peroxidases (GPXs) are major family of the reactive oxygen species (ROS) scavenging enzymes. Recently, database analysis of the Arabidopsis genome revealed a new open-reading frame, thus increasing the total number of AtGPX gene family to eight (AtGPX1–8). The effect of plant hormones like; i. e. salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), indoleacetic acid (IAA), and mannitol on the expression of the genes confirm that the AtGPX genes family is regulated by multiple signaling pathways. The survival rate of AtGPX8 knockout plants (KO8) was significantly decreased under heat stress compared with the wild type. Moreover, the content of malondialdehyde (MDA) and protein oxidation was significantly increased in the KO8 plant cells under heat stress. Results indicating that the deficiency of AtGPX8 accelerates the progression of oxidative stress in KO8 plants. On the other hand, the overexpression of AtGPX8 in E. coli cells enhance the growth of the recombinant enzyme on media supplemented with 0.2 mM cumene hydroperoxide, 0.3 mM H2O2 or 600 mM NaCl. PMID:24217216

  1. The importance of Arabidopsis glutathione peroxidase 8 for protecting Arabidopsis plant and E. coli cells against oxidative stress.

    PubMed

    Gaber, Ahmed

    2014-01-01

    Glutathione peroxidases (GPXs) are major family of the reactive oxygen species (ROS) scavenging enzymes. Recently, database analysis of the Arabidopsis genome revealed a new open-reading frame, thus increasing the total number of AtGPX gene family to eight (AtGPX1-8). The effect of plant hormones like; i. e. salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), indoleacetic acid (IAA), and mannitol on the expression of the genes confirm that the AtGPX genes family is regulated by multiple signaling pathways. The survival rate of AtGPX8 knockout plants (KO8) was significantly decreased under heat stress compared with the wild type. Moreover, the content of malondialdehyde (MDA) and protein oxidation was significantly increased in the KO8 plant cells under heat stress. Results indicating that the deficiency of AtGPX8 accelerates the progression of oxidative stress in KO8 plants. On the other hand, the overexpression of AtGPX8 in E. coli cells enhance the growth of the recombinant enzyme on media supplemented with 0.2 mM cumene hydroperoxide, 0.3 mM H 2O 2 or 600 mM NaCl.

  2. Production of an active recombinant thrombomodulin derivative in transgenic tobacco plants and suspension cells.

    PubMed

    Schinkel, Helga; Schiermeyer, Andreas; Soeur, Raphael; Fischer, Rainer; Schillberg, Stefan

    2005-06-01

    Thrombomodulin is a membrane-bound protein that plays an active role in the blood coagulation system by binding thrombin and initiating the protein C anticoagulant pathway. Solulin is a recombinant soluble derivative of human thrombomodulin. It is used for the treatment of thrombotic disorders. To evaluate the production of this pharmaceutical protein in plants, expression vectors were generated using four different N-terminal signal peptides. Immunoblot analysis of transiently transformed tobacco leaves showed that intact Solulin could be detected using three of these signal peptides. Furthermore transgenic tobacco plants and BY2 cells producing Solulin were generated. Immunoblot experiments showed that Solulin accumulated to maximum levels of 115 and 27 microg g(-1) plant material in tobacco plants and BY2 cells, respectively. Activity tests performed on the culture supernatant of transformed BY2 cells showed that the secreted Solulin was functional. In contrast, thrombomodulin activity was not detected in total soluble protein extracts from BY2 cells, probably due to inhibitory effects of substances in the cell extract. N-terminal sequencing was carried out on partially purified Solulin from the BY2 culture supernatant. The sequence was identical to that of Solulin produced in Chinese hamster ovary cells, confirming correct processing of the N-terminal signal peptide. We have demonstrated that plants and plant cell cultures can be used as alternative systems for the production of an active recombinant thrombomodulin derivative.

  3. Rapid immunohistochemical diagnosis of tobacco mosaic virus disease by microwave-assisted plant sample preparation

    PubMed Central

    Zellnig, Günther; Möstl, Stefan; Zechmann, Bernd

    2013-01-01

    Immunoelectron microscopy is a powerful method to diagnose viral diseases and to study the distribution of the viral agent within plant cells and tissues. Nevertheless, current protocols for the immunological detection of viral diseases with transmission electron microscopy (TEM) in plants take between 3 and 6 days and are therefore not suited for rapid diagnosis of virus diseases in plants. In this study, we describe a method that allows rapid cytohistochemical detection of tobacco mosaic virus (TMV) in leaves of tobacco plants. With the help of microwave irradiation, sample preparation of the leaves was reduced to 90 min. After sample sectioning, virus particles were stained on the sections by immunogold labelling of the viral coat protein, which took 100 min. After investigation with the TEM, a clear visualization of TMV in tobacco cells was achieved altogether in about half a day. Comparison of gold particle density by image analysis revealed that samples prepared with the help of microwave irradiation yielded significantly higher gold particle density as samples prepared conventionally at room temperature. This study clearly demonstrates that microwave-assisted plant sample preparation in combination with cytohistochemical localization of viral coat protein is well suited for rapid diagnosis of plant virus diseases in altogether about half a day by TEM. PMID:23580761

  4. Expression of peanut Iron Regulated Transporter 1 in tobacco and rice plants confers improved iron nutrition.

    PubMed

    Xiong, Hongchun; Guo, Xiaotong; Kobayashi, Takanori; Kakei, Yusuke; Nakanishi, Hiromi; Nozoye, Tomoko; Zhang, Lixia; Shen, Hongyun; Qiu, Wei; Nishizawa, Naoko K; Zuo, Yuanmei

    2014-07-01

    Iron (Fe) limitation is a widespread agricultural problem in calcareous soils and severely limits crop production. Iron Regulated Transporter 1 (IRT1) is a key component for Fe uptake from the soil in dicot plants. In this study, the peanut (Arachis hypogaea L.) AhIRT1 was introduced into tobacco and rice plants using an Fe-deficiency-inducible artificial promoter. Induced expression of AhIRT1 in tobacco plants resulted in accumulation of Fe in young leaves under Fe deficient conditions. Even under Fe-excess conditions, the Fe concentration was also markedly enhanced, suggesting that the Fe status did not affect the uptake and translocation of Fe by AhIRT1 in the transgenic plants. Most importantly, the transgenic tobacco plants showed improved tolerance to Fe limitation in culture in two types of calcareous soils. Additionally, the induced expression of AhIRT1 in rice plants also resulted in high tolerance to low Fe availability in calcareous soils.

  5. Co-expression of Arabidopsis transcription factor, AtMYB12, and soybean isoflavone synthase, GmIFS1, genes in tobacco leads to enhanced biosynthesis of isoflavones and flavonols resulting in osteoprotective activity.

    PubMed

    Pandey, Ashutosh; Misra, Prashant; Khan, Mohd P; Swarnkar, Gaurav; Tewari, Mahesh C; Bhambhani, Sweta; Trivedi, Ritu; Chattopadhyay, Naibedya; Trivedi, Prabodh K

    2014-01-01

    Isoflavones, a group of flavonoids, restricted almost exclusively to family Leguminosae are known to exhibit anticancerous and anti-osteoporotic activities in animal systems and have been a target for metabolic engineering in commonly consumed food crops. Earlier efforts based on the expression of legume isoflavone synthase (IFS) genes in nonlegume plant species led to the limited success in terms of isoflavone content in transgenic tissue due to the limitation of substrate for IFS enzyme. In this work to overcome this limitation, the activation of multiple genes of flavonoid pathway using Arabidopsis transcription factor AtMYB12 has been carried out. We developed transgenic tobacco lines constitutively co-expressing AtMYB12 and GmIFS1 (soybean IFS) genes or independently and carried out their phytochemical and molecular analyses. The leaves of co-expressing transgenic lines were found to have elevated flavonol content along with the accumulation of substantial amount of genistein glycoconjugates being at the highest levels that could be engineered in tobacco leaves till date. Oestrogen-deficient (ovariectomized, Ovx) mice fed with leaf extract from transgenic plant co-expressing AtMYB12 and GmIFS1 but not wild-type extract exhibited significant conservation of trabecular microarchitecture, reduced osteoclast number and expression of osteoclastogenic genes, higher total serum antioxidant levels and increased uterine oestrogenicity compared with Ovx mice treated with vehicle (control). The skeletal effect of the transgenic extract was comparable to oestrogen-treated Ovx mice. Together, our results establish an efficient strategy for successful pathway engineering of isoflavones and other flavonoids in crop plants and provide a direct evidence of improved osteoprotective effect of transgenic plant extract.

  6. Characterization of Antisense Transformed Plants Deficient in the Tobacco Anionic Peroxidase.

    PubMed Central

    Lagrimini, L. M.; Gingas, V.; Finger, F.; Rothstein, S.; Liu, TTY.

    1997-01-01

    On the basis of the biological compounds that they metabolize, plant peroxidases have long been implicated in plant growth, cell wall biogenesis, lignification, and host defenses. Transgenic tobacco (Nicotiana tabacum L.) plants that underexpress anionic peroxidase were generated using antisense RNA. The antisense RNA was found to be specific for the anionic isoenzyme and highly effective, reducing endogenous transcript levels and total peroxidase activity by as much as 1600-fold. Antisense-transformed plants appeared normal at initial observation; however, growth studies showed that plants with reduced peroxidase activity grow taller and flower sooner than control plants. In contrast, previously transformed plants overproducing anionic peroxidase were shorter and flowered later than controls. Axillary buds were more developed in antisense-transformed plants and less developed in plants overproducing this enzyme. It was found that the lignin content in leaf, stem, and root was unchanged in antisense-transformed plants, which does not support a role for anionic peroxidase in the lignification of secondary xylem vessels. However, studies of wounded tissue show some reduction in wound-induced deposition of lignin-like polymers. The data support a possible role for tobacco anionic peroxidase in host defenses but not without a reduction in growth potential. PMID:12223765

  7. Suppression of infectious TMV genomes expressed in young transgenic tobacco plants.

    PubMed

    Siddiqui, S A; Sarmiento, C; Valkonen, S; Truve, E; Lehto, K

    2007-12-01

    Full-length cDNAs of the wild-type (wt) Tobacco mosaic virus (TMV) and of the coat protein gene-deleted (DeltaCP) derivative of wt-TMV, under control of the 35S promoter and downstream ribozyme sequence to produce accurate viral transcripts, were transformed to tobacco plants to analyze plant-virus interactions through different stages of plant development. Surprisingly, young wt-TMV transgenics accumulated only very low levels of viral RNA, remained free of symptoms, and were moderately resistant against exogenous inoculations. This early resistance caused significant stress to the plants, as indicated by reduced growth. Approximately 7 to 8 weeks after germination, the resistance was broken and plants developed typical wt-TMV symptoms, with high accumulation of the viral RNAs and proteins. The DeltaCP-TMV plants likewise were initially resistant to the endogenous inoculum and were stunted, although to a lesser extent than the wt-TMV plants. The resistance was broken at the same time as in the wt-TMV plants, but the mutant replicated to much lower levels and produced much milder symptoms than the wt virus. TMV-specific small interfering RNAs as well as increased transgene methylation were detected in the plants only after the resistance break, indicating that the resistance in the young plants was not due to RNA silencing.

  8. Resistance of mature Arabidopsis plants to mechanical deformation in relation to g-force during development

    NASA Technical Reports Server (NTRS)

    Brown, A. H.

    1983-01-01

    Arabidopsis plants were grown in centrifuge tubes under well standardized culture conditions. Each plant was subjected to centrifugation (roots out) for 10 min at one of a series of centripetal forces between 7 and 390g. No deformation was observed in plants centrifuged at less than 35g. An 'average' degree of deformation was attained at about 60g. All plants exposed to more than 95g were maximally deformed but none was broken nor otherwise damaged irreversibly even at 390g. In every case new shoot growth continued normally after the centrifugation. A plant population grown on horizontal clinostats (0.5 rpm) under culture conditions exactly the same as for the upright plants responded to centrifugation stress in a way that was not substantially different from the response pattern of the plants cultured upright at 1g.

  9. Resistance of mature Arabidopsis plants to mechanical deformation in relation to g-force during development

    NASA Technical Reports Server (NTRS)

    Brown, A. H.

    1983-01-01

    Arabidopsis plants were grown in centrifuge tubes under well standardized culture conditions. Each plant was subjected to centrifugation (roots out) for 10 min at one of a series of centripetal forces between 7 and 390g. No deformation was observed in plants centrifuged at less than 35g. An 'average' degree of deformation was attained at about 60g. All plants exposed to more than 95g were maximally deformed but none was broken nor otherwise damaged irreversibly even at 390g. In every case new shoot growth continued normally after the centrifugation. A plant population grown on horizontal clinostats (0.5 rpm) under culture conditions exactly the same as for the upright plants responded to centrifugation stress in a way that was not substantially different from the response pattern of the plants cultured upright at 1g.

  10. Beyond Arabidopsis: the circadian clock in non-model plant species.

    PubMed

    McClung, C Robertson

    2013-05-01

    Circadian clocks allow plants to temporally coordinate many aspects of their biology with the diurnal cycle derived from the rotation of Earth on its axis. Although there is a rich history of the study of clocks in many plant species, in recent years much progress in elucidating the architecture and function of the plant clock has emerged from studies of the model plant, Arabidopsis thaliana. There is considerable interest in extending this knowledge of the circadian clock into diverse plant species in order to address its role in topics as varied as agricultural productivity and the responses of individual species and plant communities to global climate change and environmental degradation. The analysis of circadian clocks in the green lineage provides insight into evolutionary processes in plants and throughout the eukaryotes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. 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

  12. The calcium sensor CBL7 modulates plant responses to low nitrate in Arabidopsis.

    PubMed

    Ma, Qing; Tang, Ren-Jie; Zheng, Xiao-Jiang; Wang, Suo-Min; Luan, Sheng

    Calcium (Ca(2+)) serves as a critical messenger in a number of adaptation and developmental processes. In plants, CBL family represents a unique group of calcium sensors that decodes calcium signals. Several CBL members have been functionally characterized in the model plant Arabidopsis thaliana, but the role of CBL7 remains unknown. Here, we report that CBL7 is involved in the regulation of low-nitrate response in Arabidopsis. Expression of CBL7 was predominant in the root of young seedlings and substantially induced by nitrate starvation. Cbl7 mutant was more inhibited in root growth upon nitrate starvation compared to the wild-type. Interestingly, the growth arrest of cbl7 under low-nitrate conditions relied on acidic pH. Further analyses revealed that expression of two high-affinity nitrate transporter genes, NRT2.4 and NRT2.5, was down-regulated in cbl7 under nitrogen-starvation condition. Accordingly, the cbl7 mutant plants retained lower nitrate content than wild-type plants under low-nitrate condition. Taken together, our results uncover a novel role of CBL7 in the response to nitrate deficiency in Arabidopsis.

  13. Novel AroA from Pseudomonas putida Confers Tobacco Plant with High Tolerance to Glyphosate

    PubMed Central

    Yan, Hai-Qin; Chang, Su-Hua; Tian, Zhe-Xian; Zhang, Le; Sun, Yi-Cheng; Li, Yan; Wang, Jing; Wang, Yi-Ping

    2011-01-01

    Glyphosate is a non-selective broad-spectrum herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, also designated as AroA), a key enzyme in the aromatic amino acid biosynthesis pathway in microorganisms and plants. Previously, we reported that a novel AroA (PpAroA1) from Pseudomonas putida had high tolerance to glyphosate, with little homology to class I or class II glyphosate-tolerant AroA. In this study, the coding sequence of PpAroA1 was optimized for tobacco. For maturation of the enzyme in chloroplast, a chloroplast transit peptide coding sequence was fused in frame with the optimized aroA gene (PparoA1optimized) at the 5′ end. The PparoA1optimized gene was introduced into the tobacco (Nicotiana tabacum L. cv. W38) genome via Agrobacterium-mediated transformation. The transformed explants were first screened in shoot induction medium containing kanamycin. Then glyphosate tolerance was assayed in putative transgenic plants and its T1 progeny. Our results show that the PpAroA1 from Pseudomonas putida can efficiently confer tobacco plants with high glyphosate tolerance. Transgenic tobacco overexpressing the PparoA1optimized gene exhibit high tolerance to glyphosate, which suggest that the novel PpAroA1 is a new and good candidate applied in transgenic crops with glyphosate tolerance in future. PMID:21611121

  14. [Soil nutrients spatial variability and soil fertility suitability in Qujing tobacco-planting area].

    PubMed

    Li, Qiang; Zhou, Ji-heng; Yang, Rong-sheng; Zhang, Zheng-yan; Xie, Yan; Zhang, Yi-yang; Huang, Kua-ke; Li, Wei

    2011-04-01

    By adopting GPS technique, 2088 sampling sites were installed in the tobacco-planting area of Qujing City, Yunnan Province, with 0-20 cm soil samples collected to determine their main nutrients contents. The overall characteristics and spatial variability of the tobacco soil nutrients were analyzed by classic statistics and geo-statistics, and the soil fertility suitability in planting tobacco was evaluated by the methods of fuzzy mathematics. In the study area, soil pH and soil organic matter, available S, and water-soluble Cl contents were appropriate, soil total N and alkalihydrolyzable N contents were too high, soil available K, Ca, Mg, Cu, Fe, Zn, Mo, and Mn contents were abundant, soil available P content was at medium level, while soil total P and K and available B contents were insufficient. All the nutrient indices presented anisotropic distribution, among which, the spatial variability of soil available P and B was mainly caused by random factors, and that of other nutrients was caused by the co-effects of structural and random factors. The spatial distribution map of soil fertility suitability index (SFI) showed that there was no the excellent grade region for tobacco-planting, good grade region accounted for 8.0%, general grade region accounted for 51.6%, moderate grade region accounted for 39.0%, and low grade region accounted for 1.4%.

  15. Photosynthetic capacity of Arabidopsis plants at the reproductive stage tolerates γ irradiation.

    PubMed

    Kim, Jin-Hong; Moon, Yu Ran; Lee, Min Hee; Kim, Ji Hong; Wi, Seung Gon; Park, Bong-Ju; Kim, Cha Soon; Chung, Byung Yeoup

    2011-01-01

    The developmental stage has an influence on the overall responses of plants under biotic or abiotic stress conditions. However, there is a lack of data about the effects of ionizing radiation in plants at different developmental stages. We examined radiation sensitivity of Arabidopsis plants in terms of photosynthetic ability and oxidative stress resistance at two distinct vegetative and reproductive stages, which correspond to 23 and 43 d after seeding (DAS), respectively. When plants were exposed to γ rays at a dose rate 50 Gy h(-1) for 4 h, they were characterized as various common or differential cellular responses depending on the developmental stage. Radial expansion of leaves, inhibition of non-photochemical quenching, and production of •O(2)(-) and H(2)O(2) under methyl viologen-induced photooxidative stress were commonly more conspicuous in the irradiated leaves of both plants than in the respective control. In contrast, the 23 and 43-DAS plants were explicitly discriminated in growth, chloroplast number & ultrastructure, photosynthetic pigment content & activity, and protein damage after γ irradiation. Natural leaf senescence was thereby enhanced in the irradiated leaves of the 23-DAS plants, while it was reversely alleviated in those of the 43-DAS ones. These results suggest that photosynthetic machineries of Arabidopsis plants at the reproductive stage can be relatively tolerant to γ rays of 200 Gy.

  16. Survival of Cd-exposed Arabidopsis thaliana: are these plants reproductively challenged?

    PubMed

    Keunen, Els; Truyens, Sascha; Bruckers, Liesbeth; Remans, Tony; Vangronsveld, Jaco; Cuypers, Ann

    2011-10-01

    Plants exposed to cadmium (Cd) show morphological and physiological disorders. To increase our knowledge regarding Cd-induced signalling, most often the effects of acute exposure are investigated. However, this does not allow in-depth analysis of morphological effects. Therefore, we chronically exposed Arabidopsis thaliana plants to environmentally realistic Cd concentrations (5 or 10 μM) and, using a described phenotypic framework methodology, we determined the impact of Cd on the plant's ability to complete its life cycle and produce germinative seeds. Visible Cd-induced morphological changes were observed within a short exposure period, with chlorotic and anthocyanous leaf colouring occurring dose-dependently. Although rosette growth was severely reduced in Cd-exposed plants, all plants were able to emerge inflorescences and produce siliques containing germinative seeds, thus confirming the non-lethality of the used Cd concentrations. Although the growth inhibition of Cd-exposed plants was dependent on the dose, both concentrations had similar effects on inflorescence height and silique counts. In conclusion, vegetative growth of plants chronically exposed to Cd is inhibited in a concentration-dependent manner. However, the effect on plant regeneration is clearly stress-determined but independent on the Cd concentration applied. In Arabidopsis thaliana, vegetative and reproductive growth are differentially influenced by Cd. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  17. Jasmonate and ethylene signaling mediate whitefly-induced interference with indirect plant defense in Arabidopsis thaliana.

    PubMed

    Zhang, Peng-Jun; Broekgaarden, Colette; Zheng, Si-Jun; Snoeren, Tjeerd A L; van Loon, Joop J A; Gols, Rieta; Dicke, Marcel

    2013-03-01

    Upon herbivore attack, plants activate an indirect defense, that is, the release of a complex mixture of volatiles that attract natural enemies of the herbivore. When plants are simultaneously exposed to two herbivore species belonging to different feeding guilds, one herbivore may interfere with the indirect plant defense induced by the other herbivore. However, little is understood about the mechanisms underlying such interference. Here, we address the effect of herbivory by the phloem-feeding whitefly Bemisia tabaci on the induced indirect defense of Arabidopsis thaliana plants to Plutella xylostella caterpillars, that is, the attraction of the parasitoid wasp Diadegma semiclausum. Assays with various Arabidopsis mutants reveal that B. tabaci infestation interferes with indirect plant defense induced by P. xylostella, and that intact jasmonic acid and ethylene signaling are required for such interference caused by B. tabaci. Chemical analysis of plant volatiles showed that the composition of the blend emitted in response to the caterpillars was significantly altered by co-infestation with whiteflies. Moreover, whitefly infestation also had a considerable effect on the transcriptomic response of the plant to the caterpillars. Understanding the mechanisms underlying a plant's responses to multiple attackers will be important for the development of crop protection strategies in a multi-attacker context.

  18. Plant-in-chip: Microfluidic system for studying root growth and pathogenic interactions in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Parashar, Archana; Pandey, Santosh

    2011-06-01

    We report a microfluidic platform for the hydroponic growth of Arabidopsis plants with high-resolution visualization of root development and root-pathogen interactions. The platform comprises a set of parallel microchannels with individual input/output ports where 1-day old germinated seedlings are initially placed. Under optimum conditions, a root system grows in each microchannel and its images are recorded over a 198-h period. Different concentrations of plant growth media show different root growth characteristics. Later, the developed roots are inoculated with two plant pathogens (nematodes and zoospores) and their physicochemical interactions with the live root systems are observed.

  19. Cadmium tolerance and phytochelatin content of Arabidopsis seedlings over-expressing the phytochelatin synthase gene AtPCS1

    PubMed Central

    Brunetti, Patrizia; Zanella, Letizia; Proia, Alessandra; De Paolis, Angelo; Falasca, Giuseppina; Altamura, Maria Maddalena; Sanità di Toppi, Luigi; Costantino, Paolo; Cardarelli, Maura

    2011-01-01

    Previous studies demonstrated that expression of the Arabidopsis phytochelatin (PC) biosynthetic gene AtPCS1 in Nicotiana tabacum plants increases the Cd tolerance in the presence of exogenous glutathione (GSH). In this paper, the Cd tolerance of Arabidopsis plants over-expressing AtPCS1 (AtPCSox lines) has been analysed and the differences between Arabidopsis and tobacco are shown. Based on the analysis of seedling fresh weight, primary root length, and alterations in root anatomy, evidence is provided that, at relatively low Cd concentrations, the Cd tolerance of AtPCSox lines is lower than the wild type, while AtPCS1 over-expressing tobacco is more tolerant to Cd than the wild type. At higher Cd concentrations, Arabidopsis AtPCSox seedlings are more tolerant to Cd than the wild type, while tobacco AtPCS1 seedlings are as sensitive as the wild type. Exogenous GSH, in contrast to what was observed in tobacco, did not increase the Cd tolerance of AtPCSox lines. The PC content in wild-type Arabidopsis at low Cd concentrations is more than three times higher than in tobacco and substantial differences were also found in the PC chain lengths. These data indicate that the differences in Cd tolerance and in its dependence on exogenous GSH between Arabidopsis and tobacco are due to species-specific differences in the endogenous content of PCs and GSH and may be in the relative abundance of PCs of different length. PMID:21841172

  20. Cadmium tolerance and phytochelatin content of Arabidopsis seedlings over-expressing the phytochelatin synthase gene AtPCS1.

    PubMed

    Brunetti, Patrizia; Zanella, Letizia; Proia, Alessandra; De Paolis, Angelo; Falasca, Giuseppina; Altamura, Maria Maddalena; Sanità di Toppi, Luigi; Costantino, Paolo; Cardarelli, Maura

    2011-11-01

    Previous studies demonstrated that expression of the Arabidopsis phytochelatin (PC) biosynthetic gene AtPCS1 in Nicotiana tabacum plants increases the Cd tolerance in the presence of exogenous glutathione (GSH). In this paper, the Cd tolerance of Arabidopsis plants over-expressing AtPCS1 (AtPCSox lines) has been analysed and the differences between Arabidopsis and tobacco are shown. Based on the analysis of seedling fresh weight, primary root length, and alterations in root anatomy, evidence is provided that, at relatively low Cd concentrations, the Cd tolerance of AtPCSox lines is lower than the wild type, while AtPCS1 over-expressing tobacco is more tolerant to Cd than the wild type. At higher Cd concentrations, Arabidopsis AtPCSox seedlings are more tolerant to Cd than the wild type, while tobacco AtPCS1 seedlings are as sensitive as the wild type. Exogenous GSH, in contrast to what was observed in tobacco, did not increase the Cd tolerance of AtPCSox lines. The PC content in wild-type Arabidopsis at low Cd concentrations is more than three times higher than in tobacco and substantial differences were also found in the PC chain lengths. These data indicate that the differences in Cd tolerance and in its dependence on exogenous GSH between Arabidopsis and tobacco are due to species-specific differences in the endogenous content of PCs and GSH and may be in the relative abundance of PCs of different length.

  1. Use of Arabidopsis eceriferum mutants to explore plant cuticle biosynthesis.

    PubMed

    Samuels, Lacey; DeBono, Allan; Lam, Patricia; Wen, Miao; Jetter, Reinhard; Kunst, Ljerka

    2008-05-31

    The plant cuticle is a waxy outer covering on plants that has a primary role in water conservation, but is also an important barrier against the entry of pathogenic microorganisms. The cuticle is made up of a tough crosslinked polymer called "cutin" and a protective wax layer that seals the plant surface. The waxy layer of the cuticle is obvious on many plants, appearing as a shiny film on the ivy leaf or as a dusty outer covering on the surface of a grape or a cabbage leaf thanks to light scattering crystals present in the wax. Because the cuticle is an essential adaptation of plants to a terrestrial environment, understanding the genes involved in plant cuticle formation has applications in both agriculture and forestry. Today, we'll show the analysis of plant cuticle mutants identified by forward and reverse genetics approaches.

  2. Programming of Plant Leaf Senescence with Temporal and Inter-Organellar Coordination of Transcriptome in Arabidopsis.

    PubMed

    Woo, Hye Ryun; Koo, Hee Jung; Kim, Jeongsik; Jeong, Hyobin; Yang, Jin Ok; Lee, Il Hwan; Jun, Ji Hyung; Choi, Seung Hee; Park, Su Jin; Kang, Byeongsoo; Kim, You Wang; Phee, Bong-Kwan; Kim, Jin Hee; Seo, Chaehwa; Park, Charny; Kim, Sang Cheol; Park, Seongjin; Lee, Byungwook; Lee, Sanghyuk; Hwang, Daehee; Nam, Hong Gil; Lim, Pyung Ok

    2016-05-01

    Plant leaves, harvesting light energy and fixing CO2, are a major source of foods on the earth. Leaves undergo developmental and physiological shifts during their lifespan, ending with senescence and death. We characterized the key regulatory features of the leaf transcriptome during aging by analyzing total- and small-RNA transcriptomes throughout the lifespan of Arabidopsis (Arabidopsis thaliana) leaves at multidimensions, including age, RNA-type, and organelle. Intriguingly, senescing leaves showed more coordinated temporal changes in transcriptomes than growing leaves, with sophisticated regulatory networks comprising transcription factors and diverse small regulatory RNAs. The chloroplast transcriptome, but not the mitochondrial transcriptome, showed major changes during leaf aging, with a strongly shared expression pattern of nuclear transcripts encoding chloroplast-targeted proteins. Thus, unlike animal aging, leaf senescence proceeds with tight temporal and distinct interorganellar coordination of various transcriptomes that would be critical for the highly regulated degeneration and nutrient recycling contributing to plant fitness and productivity.

  3. The Arabidopsis unannotated secreted peptide database, a resource for plant peptidomics.

    PubMed

    Lease, Kevin A; Walker, John C

    2006-11-01

    In the era of genomics, if a gene is not annotated, it is not investigated. Due to their small size, genes encoding peptides are often missed in genome annotations. Secreted peptides are important regulators of plant growth, development, and physiology. Identification of additional peptide signals by sequence homology searches has had limited success due to sequence heterogeneity. A bioinformatics approach was taken to find unannotated Arabidopsis (Arabidopsis thaliana) peptides. Arabidopsis chromosome sequences were searched for all open reading frames (ORFs) encoding peptides and small proteins between 25 and 250 amino acids in length. The translated ORFs were then sequentially queried for the presence of an amino-terminal cleavable signal peptide, the absence of transmembrane domains, and the absence of endoplasmic reticulum lumenal retention sequences. Next, the ORFs were filtered against the The Arabidopsis Information Resource 6.0 annotated Arabidopsis genes to remove those ORFs overlapping known genes. The remaining 33,809 ORFs were placed in a relational database to which additional annotation data were deposited. Genome-wide tiling array data were compared with the coordinates of the ORFs, supporting the possibility that many of the ORFs may be expressed. In addition, clustering and sequence similarity analyses revealed that many of the putative peptides are in gene families and/or appear to be present in the rice (Oryza sativa) genome. A subset of the ORFs was evaluated by reverse transcription-PCR and, for one-fifth of those, expression was detected. These results support the idea that the number and diversity of plant peptides is broader than currently assumed. The peptides identified and their annotation data may be viewed or downloaded through a searchable Web interface at peptidome.missouri.edu.

  4. Growth and certain chemical constituents of tobacco plants exposed to air ions

    NASA Astrophysics Data System (ADS)

    Barthakur, N. N.; Arnold, N. P.

    1988-06-01

    Controlled experiments were performed in Faraday cages on the effects of positive and negative air ions on flue-cured tobacco plants. Continuous exposures for 15 days to air ions showed no significant differences in any plant growth characteristic between the treated and control plants. Standard errors in the measurement of the growth parameters for ion exposed plants were, however, consistently higher than those of control plants. Spatial variation in concentration gradients of air ions produced by corona discharge might have contributed to masking of the relatively small effects of air ions on biological organisms observed in previous experiments in this laboratory. No significant difference was observed between the experimental and control plants in nicotine, total alkaloid, and reducing sugar contents. Total nitrogen content was slightly higher for treated than control plants.

  5. Accumulation of ricinoleic, lesquerolic, and densipolic acids in seeds of transgenic Arabidopsis plants that express a fatty acyl hydroxylase cDNA from castor bean.

    PubMed Central

    Broun, P; Somerville, C

    1997-01-01

    A cDNA encoding the oleate 12-hydroxylase from castor bean (Ricinus communis L.) has previously been shown to direct the synthesis of small amounts of ricinoleic acid (12-hydroxyoctadec-cis-9-enoic acid) in seeds of transgenic tobacco plants. Expression of the cDNA under control of the Brassica napus napin promoter in transgenic Arabidopsis thaliana plants resulted in the accumulation of up to 17% of seed fatty acids as ricinoleate and two novel fatty acids that have been identified by gas chromatography-mass spectrometry as lesquerolic (14-hydroxyeicos-cis-11-enoic acid) and densipolic (12-hydroxyoctadec-cis-9,15-dienoic acid) acids. Traces of auricolic acid were also observed. These results suggest that either the castor hydroxylase can utilize oleic acid and eicosenoic acid as substrates for ricinoleic and lesquerolic acid biosynthesis, respectively, or Arabidopsis contains an elongase that accepts ricinoleic acid as a substrate. These observations are also consistent with indirect biochemical evidence that an n-3 desaturase is capable of converting ricinoleic acid to densipolic acid. Expression of the castor hydroxylase also caused enhanced accumulation of oleic acid and a corresponding decrease in the levels of polyunsaturated fatty acids. Since the steady-state level of mRNA for the oleate-12 desaturase was not affected, it appears that the presence of the hydroxylase, directly or indirectly, causes posttranscriptional inhibition of desaturation. PMID:9085577

  6. Catalase function in plants: a focus on Arabidopsis mutants as stress-mimic models.

    PubMed

    Mhamdi, Amna; Queval, Guillaume; Chaouch, Sejir; Vanderauwera, Sandy; Van Breusegem, Frank; Noctor, Graham

    2010-10-01

    Hydrogen peroxide (H(2)O(2)) is an important signal molecule involved in plant development and environmental responses. Changes in H(2)O(2) availability can result from increased production or decreased metabolism. While plants contain several types of H(2)O(2)-metabolizing proteins, catalases are highly active enzymes that do not require cellular reductants as they primarily catalyse a dismutase reaction. This review provides an update on plant catalase genes, function, and subcellular localization, with a focus on recent information generated from studies on Arabidopsis. Original data are presented on Arabidopsis catalase single and double mutants, and the use of some of these lines as model systems to investigate the outcome of increases in intracellular H(2)O(2) are discussed. Particular attention is paid to interactions with cell thiol-disulphide status; the use of catalase-deficient plants to probe the apparent redundancy of reductive H(2)O(2)-metabolizing pathways; the importance of irradiance and growth daylength in determining the outcomes of catalase deficiency; and the induction of pathogenesis-related responses in catalase-deficient lines. Within the context of strategies aimed at understanding and engineering plant stress responses, the review also considers whether changes in catalase activities in wild-type plants are likely to be a significant part of plant responses to changes in environmental conditions or biotic challenge.

  7. The Powdery Mildew Disease of Arabidopsis: A Paradigm for the Interaction between Plants and Biotrophic Fungi

    PubMed Central

    Micali, Cristina; Göllner, Katharina; Humphry, Matt; Consonni, Chiara; Panstruga, Ralph

    2008-01-01

    The powdery mildew diseases, caused by fungal species of the Erysiphales, have an important economic impact on a variety of plant species and have driven basic and applied research efforts in the field of phytopathology for many years. Although the first taxonomic reports on the Erysiphales date back to the 1850's, advances into the molecular biology of these fungal species have been hampered by their obligate biotrophic nature and difficulties associated with their cultivation and genetic manipulation in the laboratory. The discovery in the 1990's of a few species of powdery mildew fungi that cause disease on Arabidopsis has opened a new chapter in this research field. The great advantages of working with a model plant species have translated into remarkable progress in our understanding of these complex pathogens and their interaction with the plant host. Herein we summarize advances in the study of Arabidopsis-powdery mildew interactions and discuss their implications for the general field of plant pathology. We provide an overview of the life cycle of the pathogens on Arabidopsis and describe the structural and functional changes that occur during infection in the host and fungus in compatible and incompatible interactions, with special emphasis on defense signaling, resistance pathways, and compatibility factors. Finally, we discuss the future of powdery mildew research in anticipation of the sequencing of multiple powdery mildew genomes. The cumulative body of knowledge on powdery mildews of Arabidopsis provides a valuable tool for the study and understanding of disease associated with many other obligate biotrophic pathogen species. PMID:22303240

  8. Nighttime sugar starvation orchestrates gibberellin biosynthesis and plant growth in Arabidopsis.

    PubMed

    Paparelli, Eleonora; Parlanti, Sandro; Gonzali, Silvia; Novi, Giacomo; Mariotti, Lorenzo; Ceccarelli, Nello; van Dongen, Joost T; Kölling, Katharina; Zeeman, Samuel C; Perata, Pierdomenico

    2013-10-01

    A plant's eventual size depends on the integration of its genetic program with environmental cues, which vary on a daily basis. Both efficient carbon metabolism and the plant hormone gibberellin are required to guarantee optimal plant growth. Yet, little is known about the interplay between carbon metabolism and gibberellins that modulates plant growth. Here, we show that sugar starvation in Arabidopsis thaliana arising from inefficient starch metabolism at night strongly reduces the expression of ent-kaurene synthase, a key regulatory enzyme for gibberellin synthesis, the following day. Our results demonstrate that plants integrate the efficiency of photosynthesis over a period of days, which is transduced into a daily rate of gibberellin biosynthesis. This enables a plant to grow to a size that is compatible with its environment.

  9. [The influence of selected plants on the tobacco smoking-induced effects in the oral cavity--review].

    PubMed

    Kedziora, Agata; Raś, Katarzyna; Grzech-Leśniak, Kinga; Wyganowska-Swiatkowska, Marzena

    2015-01-01

    Tobacco smoking is a culprit of many pathological lesions on the oral mucosa. In this literature review we focused on various therapeutic options for tobacco induced mucosal pathologies. Many active ingredients of Aloe vera, Chamomile, Curcuma longa and Calendula show potent anti-inflammatory and regenerative activity, making plant derived drugs a reasonable option for traditional pharmaceuticals.

  10. 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

  11. Overexpression of monoubiquitin improves photosynthesis in transgenic tobacco plants following high temperature stress.

    PubMed

    Tian, Fengxia; Gong, Jiangfeng; Zhang, Jin; Feng, Yanan; Wang, Guokun; Guo, Qifang; Wang, Wei

    2014-09-01

    The ubiquitin/26S proteasome system (Ub/26S) is implicated in abiotic stress responses in plants. In this paper, transgenic tobacco plants overexpressing Ta-Ub2 from wheat were used to study the functions of Ub in the improvement of photosynthesis under high temperature (45°C) stress. We observed higher levels of Ub conjugates in transgenic plants under high temperature stress conditions compared to wild type (WT) as a result of the constitutive overexpression of Ta-Ub2, suggesting increased protein degradation by the 26S proteasome system under high temperature stress. Overexpressing Ub increased the photosynthetic rate (Pn) of transgenic tobacco plants, consistent with the improved ATPase activity in the thylakoid membrane and enhanced efficiency of PSII photochemistry. The higher D1 protein levels following high temperature stress in transgenic plants than WT were also observed. These findings imply that Ub may be involved in tolerance of photosynthesis to high temperature stress in plants. Compared with WT, the transgenic plants showed lower protein carbonylation and malondialdehyde (MDA) levels, less reactive oxygen species (ROS) accumulation, but higher antioxidant enzyme activity under high temperature stress. These findings suggest that the improved antioxidant capacity of transgenic plants may be one of the most important mechanisms underlying Ub-regulated high temperature tolerance.

  12. Cell wall modifications in Arabidopsis plants with altered alpha-L-arabinofuranosidase activity.

    PubMed

    Chávez Montes, Ricardo A; Ranocha, Philippe; Martinez, Yves; Minic, Zoran; Jouanin, Lise; Marquis, Mélanie; Saulnier, Luc; Fulton, Lynette M; Cobbett, Christopher S; Bitton, Frédérique; Renou, Jean-Pierre; Jauneau, Alain; Goffner, Deborah

    2008-05-01

    Although cell wall remodeling is an essential feature of plant growth and development, the underlying molecular mechanisms are poorly understood. This work describes the characterization of Arabidopsis (Arabidopsis thaliana) plants with altered expression of ARAF1, a bifunctional alpha-L-arabinofuranosidase/beta-D-xylosidase (At3g10740) belonging to family 51 glycosyl-hydrolases. ARAF1 was localized in several cell types in the vascular system of roots and stems, including xylem vessels and parenchyma cells surrounding the vessels, the cambium, and the phloem. araf1 T-DNA insertional mutants showed no visible phenotype, whereas transgenic plants that overexpressed ARAF1 exhibited a delay in inflorescence emergence and altered stem architecture. Although global monosaccharide analysis indicated only slight differences in cell wall composition in both mutant and overexpressing lines, immunolocalization experiments using anti-arabinan (LM6) and anti-xylan (LM10) antibodies indicated cell type-specific alterations in cell wall structure. In araf1 mutants, an increase in LM6 signal intensity was observed in the phloem, cambium, and xylem parenchyma in stems and roots, largely coinciding with ARAF1 expression sites. The ectopic overexpression of ARAF1 resulted in an increase in LM10 labeling in the secondary walls of interfascicular fibers and xylem vessels. The combined ARAF1 gene expression and immunolocalization studies suggest that arabinan-containing pectins are potential in vivo substrates of ARAF1 in Arabidopsis.

  13. Cell Wall Modifications in Arabidopsis Plants with Altered α-l-Arabinofuranosidase Activity[C][W

    PubMed Central

    Chávez Montes, Ricardo A.; Ranocha, Philippe; Martinez, Yves; Minic, Zoran; Jouanin, Lise; Marquis, Mélanie; Saulnier, Luc; Fulton, Lynette M.; Cobbett, Christopher S.; Bitton, Frédérique; Renou, Jean-Pierre; Jauneau, Alain; Goffner, Deborah

    2008-01-01

    Although cell wall remodeling is an essential feature of plant growth and development, the underlying molecular mechanisms are poorly understood. This work describes the characterization of Arabidopsis (Arabidopsis thaliana) plants with altered expression of ARAF1, a bifunctional α-l-arabinofuranosidase/β-d-xylosidase (At3g10740) belonging to family 51 glycosyl-hydrolases. ARAF1 was localized in several cell types in the vascular system of roots and stems, including xylem vessels and parenchyma cells surrounding the vessels, the cambium, and the phloem. araf1 T-DNA insertional mutants showed no visible phenotype, whereas transgenic plants that overexpressed ARAF1 exhibited a delay in inflorescence emergence and altered stem architecture. Although global monosaccharide analysis indicated only slight differences in cell wall composition in both mutant and overexpressing lines, immunolocalization experiments using anti-arabinan (LM6) and anti-xylan (LM10) antibodies indicated cell type-specific alterations in cell wall structure. In araf1 mutants, an increase in LM6 signal intensity was observed in the phloem, cambium, and xylem parenchyma in stems and roots, largely coinciding with ARAF1 expression sites. The ectopic overexpression of ARAF1 resulted in an increase in LM10 labeling in the secondary walls of interfascicular fibers and xylem vessels. The combined ARAF1 gene expression and immunolocalization studies suggest that arabinan-containing pectins are potential in vivo substrates of ARAF1 in Arabidopsis. PMID:18344421

  14. Overexpression of Arabidopsis NLP7 improves plant growth under both nitrogen-limiting and -sufficient conditions by enhancing nitrogen and carbon assimilation.

    PubMed

    Yu, Lin-Hui; Wu, Jie; Tang, Hui; Yuan, Yang; Wang, Shi-Mei; Wang, Yu-Ping; Zhu, Qi-Sheng; Li, Shi-Gui; Xiang, Cheng-Bin

    2016-06-13

    Nitrogen is essential for plant survival and growth. Excessive application of nitrogenous fertilizer has generated serious environment pollution and increased production cost in agriculture. To deal with this problem, tremendous efforts have been invested worldwide to increase the nitrogen use ability of crops. However, only limited success has been achieved to date. Here we report that NLP7 (NIN-LIKE PROTEIN 7) is a potential candidate to improve plant nitrogen use ability. When overexpressed in Arabidopsis, NLP7 increases plant biomass under both nitrogen-poor and -rich conditions with better-developed root system and reduced shoot/root ratio. NLP7-overexpressing plants show a significant increase in key nitrogen metabolites, nitrogen uptake, total nitrogen content, and expression levels of genes involved in nitrogen assimilation and signalling. More importantly, overexpression of NLP7 also enhances photosynthesis rate and carbon assimilation, whereas knockout of NLP7 impaired both nitrogen and carbon assimilation. In addition, NLP7 improves plant growth and nitrogen use in transgenic tobacco (Nicotiana tabacum). Our results demonstrate that NLP7 significantly improves plant growth under both nitrogen-poor and -rich conditions by coordinately enhancing nitrogen and carbon assimilation and sheds light on crop improvement.

  15. Overexpression of Arabidopsis NLP7 improves plant growth under both nitrogen-limiting and -sufficient conditions by enhancing nitrogen and carbon assimilation

    PubMed Central

    Yu, Lin-Hui; Wu, Jie; Tang, Hui; Yuan, Yang; Wang, Shi-Mei; Wang, Yu-Ping; Zhu, Qi-Sheng; Li, Shi-Gui; Xiang, Cheng-Bin

    2016-01-01

    Nitrogen is essential for plant survival and growth. Excessive application of nitrogenous fertilizer has generated serious environment pollution and increased production cost in agriculture. To deal with this problem, tremendous efforts have been invested worldwide to increase the nitrogen use ability of crops. However, only limited success has been achieved to date. Here we report that NLP7 (NIN-LIKE PROTEIN 7) is a potential candidate to improve plant nitrogen use ability. When overexpressed in Arabidopsis, NLP7 increases plant biomass under both nitrogen-poor and -rich conditions with better-developed root system and reduced shoot/root ratio. NLP7–overexpressing plants show a significant increase in key nitrogen metabolites, nitrogen uptake, total nitrogen content, and expression levels of genes involved in nitrogen assimilation and signalling. More importantly, overexpression of NLP7 also enhances photosynthesis rate and carbon assimilation, whereas knockout of NLP7 impaired both nitrogen and carbon assimilation. In addition, NLP7 improves plant growth and nitrogen use in transgenic tobacco (Nicotiana tabacum). Our results demonstrate that NLP7 significantly improves plant growth under both nitrogen-poor and -rich conditions by coordinately enhancing nitrogen and carbon assimilation and sheds light on crop improvement. PMID:27293103

  16. Plant Cell Division Analyzed by Transient Agrobacterium-Mediated Transformation of Tobacco BY-2 Cells.

    PubMed

    Buschmann, Henrik

    2016-01-01

    The continuing analysis of plant cell division will require additional protein localization studies. This is greatly aided by GFP-technology, but plant transformation and the maintenance of transgenic lines can present a significant technical bottleneck. In this chapter I describe a method for the Agrobacterium-mediated genetic transformation of tobacco BY-2 cells. The method allows for the microscopic analysis of fluorescence-tagged proteins in dividing cells in within 2 days after starting a coculture. This transient transformation procedure requires only standard laboratory equipment. It is hoped that this rapid method would aid researchers conducting live-cell localization studies in plant mitosis and cytokinesis.

  17. Analysis of plant growth-promoting properties of Bacillus amyloliquefaciens UCMB5113 using Arabidopsis thaliana as host plant.

    PubMed

    Asari, Shashidar; Tarkowská, Danuše; Rolčík, Jakub; Novák, Ondřej; Palmero, David Velázquez; Bejai, Sarosh; Meijer, Johan

    2017-01-01

    This study showed that Bacillus amyloliquefaciens UCMB5113 colonizing Arabidopsis roots changed root structure and promoted growth implying the usability of this strain as a novel tool to support sustainable crop production. Root architecture plays a crucial role for plants to ensure uptake of water, minerals and nutrients and to provide anchorage in the soil. The root is a dynamic structure with plastic growth and branching depending on the continuous integration of internal and environmental factors. The rhizosphere contains a complex microbiota, where some microbes can colonize plant roots and support growth and stress tolerance. Here, we report that the rhizobacterium Bacillus amyloliquefaciens subsp. plantarum UCMB5113 stimulated the growth of Arabidopsis thaliana Col-0 by increased lateral root outgrowth and elongation and root-hair formation, although primary root elongation was inhibited. In addition, the growth of the above ground tissues was stimulated by UCMB5113. Specific hormone reporter gene lines were tested which suggested a role for at least auxin and cytokinin signaling during rhizobacterial modulation of Arabidopsis root architecture. UCMB5113 produced cytokinins and indole-3-acetic acid, and the formation of the latter was stimulated by root exudates and tryptophan. The plant growth promotion effect by UCMB5113 did not appear to depend on jasmonic acid in contrast to the disease suppression effect in plants. UCMB5113 exudates inhibited primary root growth, while a semi-purified lipopeptide fraction did not and resulted in the overall growth promotion indicating an interplay of many different bacterial compounds that affect the root growth of the host plant. This study illustrates that beneficial microbes interact with plants in root development via classic and novel signals.

  18. PDH45 overexpressing transgenic tobacco and rice plants provide salinity stress tolerance via less sodium accumulation.

    PubMed

    Nath, Manoj; Garg, Bharti; Sahoo, Ranjan Kumar; Tuteja, Narendra

    2015-01-01

    Salinity stress negatively affects the crop productivity worldwide, including that of rice. Coping with these losses is a major concern for all countries. The pea DNA helicase, PDH45 is a unique member of helicase family involved in the salinity stress tolerance. However, the exact mechanism of the PDH45 in salinity stress tolerance is yet to be established. Therefore, the present study was conducted to investigate the mechanism of PDH45-mediated salinity stress tolerance in transgenic tobacco and rice lines along with wild type (WT) plants using CoroNa Green dye based sodium localization in root and shoot sections. The results showed that under salinity stress root and shoot of PDH45 overexpressing transgenic tobacco and rice accumulated less sodium (Na(+)) as compared to their respective WT. The present study also reports salinity tolerant (FL478) and salinity susceptible (Pusa-44) varieties of rice accumulated lowest and highest Na(+) level, respectively. All the varieties and transgenic lines of rice accumulate differential Na(+) ions in root and shoot. However, roots accumulate high Na(+) as compared to the shoots in both tobacco and rice transgenic lines suggesting that the Na(+) transport in shoot is somehow inhibited. It is proposed that the PDH45 is probably involved in the deposition of apoplastic hydrophobic barriers and consequently inhibit Na(+) transport to shoot and therefore confers salinity stress tolerance to PDH45 overexpressing transgenic lines. This study concludes that tobacco (dicot) and rice (monocot) transgenic plants probably share common salinity tolerance mechanism mediated by PDH45 gene.

  19. The evidence of Tobacco rattle virus impact on host plant organelles ultrastructure.

    PubMed

    Otulak, Katarzyna; Chouda, Marcin; Bujarski, Józef; Garbaczewska, Grażyna

    2015-03-01

    Tobraviruses, like other (+) stranded RNA viruses of plants, replicate their genome in cytoplasm and use such usual membranous structures like endoplasmic reticulum. Based on the ultrastructural examination of Tobacco rattle virus (TRV)-infected potato and tobacco leaf tissues, in this work we provide evidence of the participation of not only the membranous and vesicular ER structures but also other cell organelles during the viral infection cycle. Non-capsidated TRV PSG particles (potato isolate from the Netherlands) (long and short forms) were observed inside the nucleus while the presence of TRV capsid protein (CP) was detected in the nucleus caryolymph and within the nucleolus area. Both capsidated and non-capsidated viral particles were localized inside the strongly disorganized chloroplasts and mitochondria. The electron-dense TRV particles were connected with vesicular structures of mitochondria as well as with chloroplasts in both potato and tobacco tissues. At 15-30 days after infection, vesicles filled with TRV short particles were visible in mitochondria revealing the expanded cristae structures. Immunodetection analysis revealed the TRV PSG CP epitope inside chloroplast with disorganized thylakoids structure as well as in mitochondria of different tobacco and potato tissues. The ultrastructural analysis demonstrated high dynamics of the main cell organelles during the TRV PSG-Solanaceous plants interactions. Moreover, our results suggest a relationship between organelle changes and different stages of virus infection cycle and/or particle formation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Tryptamine-induced resistance in tryptophan decarboxylase transgenic poplar and tobacco plants against their specific herbivores.

    PubMed

    Gill, Rishi I S; Ellis, Brian E; Isman, Murray B

    2003-04-01

    The presence of amines and their derivatives in plant tissues is known to influence insect feeding and reproduction. The enzyme tryptophan decarboxylase (TDC) catalyzes the decarboxylation of tryptophan to tryptamine, which is both a bioactive amine and a precursor of other indole derivatives. Transgenic poplar and tobacco plants ectopically expressing TDC1 accumulated elevated levels of tryptamine without affecting plant growth and development. This accumulation was consistently associated with adverse effects on feeding behavior and physiology of Malacosoma disstria Hub. (forest tent caterpillar, FTC) and Manduca sexta L. (tobacco hornworm, THW). Behavior studies with FTC and THW larvae showed that acceptability of the leaf tissue to larvae was inversely related to foliar tryptamine levels. Physiological studies with FTC and THW larvae showed that consumption of leaf tissue from the transgenic lines is deleterious to larvae growth, apparently due to a postingestive mechanism. Thus, ectopic expression of TDC1 can allow sufficient tryptamine to accumulate in poplar and tobacco leaf tissue to suppress significantly the growth of insect pests that normally feed on these plants.

  1. A dehydrin gene isolated from feral olive enhances drought tolerance in Arabidopsis transgenic plants

    PubMed Central

    Chiappetta, Adriana; Muto, Antonella; Bruno, Leonardo; Woloszynska, Magdalena; Lijsebettens, Mieke Van; Bitonti, Maria B.

    2015-01-01

    Dehydrins belong to a protein family whose expression may be induced or enhanced by developmental process and environmental stresses that lead to cell dehydration. A dehydrin gene named OesDHN was isolated and characterized from oleaster (Olea europaea L. subsp. europaea, var. sylvestris), the wild form of olive. To elucidate the contribution of OesDHN in the development of drought tolerance, its expression levels were investigated in oleaster plants during development and under drought stress condition. The involvement of OesDHN in plant stress response was also evaluated in Arabidopsis transgenic lines, engineered to overexpress this gene, and exposed to a controlled mild osmotic stress. OesDHN expression was found to be modulated during development and induced under mild drought stress in oleaster plants. In addition, the Arabidopsis transgenic plants showed a better tolerance to osmotic stress than wild-type plants. The results demonstrated that OesDHN expression is induced by drought stress and is able to confer osmotic stress tolerance. We suggest a role for OesDHN, as a putative functional marker of plant stress tolerance. PMID:26175736

  2. NIMA-related kinase NEK6 affects plant growth and stress response in Arabidopsis.

    PubMed

    Zhang, Bo; Chen, Hao-Wei; Mu, Rui-Ling; Zhang, Wang-Ke; Zhao, Ming-Yu; Wei, Wei; Wang, Fang; Yu, Hui; Lei, Gang; Zou, Hong-Feng; Ma, Biao; Chen, Shou-Yi; Zhang, Jin-Song

    2011-12-01

    The NIMA-related kinases (NEKs) are a family of serine/threonine kinases involved largely in cell cycle control in fungi, mammals and other eukaryotes. In Arabidopsis, NEK6 is involved in the regulation of epidermal cell morphogenesis. However, other roles of NEK6 in plants are less well understood. Here we report functions of NEK6 in plant growth, development and stress responses in Arabidopsis. NEK6 transcripts and proteins are induced by ethylene precursor ACC and salt stress. Expression of other NEK genes except NEK5 is also responsive to the two treatments. Overexpression and mutant analysis disclose that the NEK6 gene increases rosette growth, seed yield and lateral root formation. However, NEK6 appears to play a negative role in the control of seed size. The gene also promotes plant tolerance to salt stress and osmotic stress in its overexpressing plants. The NEK6 gene may achieve its function through suppression of ethylene biosynthesis and activation of CYCB1;1 and CYCA3;1 expression. Our present study reveals new functions of the NEK6 gene in plant growth and stress tolerance, and manipulation of NEK6 may improve important agronomic traits in crop plants.

  3. Delayed Leaf Senescence in Tobacco Plants Transformed with tmr, a Gene for Cytokinin Production in Agrobacterium.

    PubMed Central

    Smart, CM; Scofield, SR; Bevan, MW; Dyer, TA

    1991-01-01

    The aim of this study was to investigate whether enhanced levels of endogenous cytokinins could influence plant development, particularly leaf senescence. Tobacco plants were transformed with the Agrobacterium tumefaciens gene tmr, under the control of the soybean heat shock promoter HS6871. This gene encodes the enzyme isopentenyl transferase, which catalyzes the initial step in cytokinin biosynthesis. After heat shock, the cytokinin level increased greatly and the level of tmr mRNA, undetectable at 20[deg]C, rose and remained high for up to 8 hours. The levels of cytokinin and tmr mRNA were substantially lower by 24 hours. Transformed plants grown at 20[deg]C were shorter, had larger side shoots, and remained green for longer than untransformed plants. The differences were more pronounced after several heat shocks of whole plants or defined areas of leaves. Our results demonstrated that plant morphology and leaf senescence can be manipulated by changing the endogenous level of cytokinins. PMID:12324608

  4. Identification of the plant ribokinase and discovery of a role for Arabidopsis ribokinase in nucleoside metabolism

    DOE PAGES

    Riggs, John W.; Rockwell, Nathan C.; Cavales, Philip C.; ...

    2016-09-06

    Ribose can be used for energy or as a component of several important biomolecules, but for it to be used in either capacity it must first be phosphorylated by ribokinase (RBSK). RBSK proteins are part of the phosphofructokinase-B (pfkB) family of carbohydrate kinases. Sequence comparisons of pfkB proteins from the model plant Arabidopsis thaliana with the human and Escherichia coli RBSK identified a single candidate RBSK, At1g17160 (AtRBSK). AtRBSK is more similar to predicted RBSKs from other plant species and known mammalian and prokaryotic RBSK than to all other PfkB proteins in Arabidopsis. AtRBSK contains a predicted chloroplast transit peptide,more » and we confirmed plastid localization using AtRBSK fused to YFP. Structure prediction software verified that the AtRBSK sequence mapped onto a known RBSK structure. Kinetic parameters of purified recombinant AtRBSK were determined to be Kmribose = 150 μm ± 17 μm, KmATP = 45 μm ± 5.6 μm, and kcat = 2.0 s₋1. Substrate inhibition was observed for AtRBSK (KiATP = 2.44 mm ± 0.36 mm), as has been demonstrated for other RBSK proteins. Ribose accumulated in Arabidopsis plants lacking AtRBSK. Such plants grew normally unless media was supplemented with ribose, which led to chlorosis and growth inhibition. Both chlorosis and ribose accumulation were abolished upon the introduction of a transgene expressing AtRBSK-MYC, demonstrating that the loss of protein is responsible for ribose hypersensitivity. Lastly, ribose accumulation in plants lacking AtRBSK was reduced in plants also deficient in the nucleoside ribohydrolase NSH1, linking AtRBSK activity to nucleoside metabolism.« less

  5. Gravity response mechanisms of lateral organs and the control of plant architecture in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Mullen, J.; Hangarter, R.

    Most research on gravity responses in plants has focused on primary roots and shoots, which typically grow in a vertical orientation. However, the patterns of lateral organ formation and their growth orientation, which typically are not vertical, govern plant architecture. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting the overall root system architecture. We have found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth of the new lateral roots is determined by what is called the gravitropic set-point angle (GSA). In Arabidopsis shoots, rosette leaves and inflorescence branches also display GSA-dependent developmental changes in their orientation. The developmental control of the GSA of lateral organs in Arabidopsis provides us with a useful system for investigating the components involved in regulating directionality of tropistic responses. We have identified several Arabidopsis mutants that have either altered lateral root orientations, altered orientation of lateral organs in the shoot, or both, but maintain normal primary organ orientation. The mgsa ({m}odified {g}ravitropic {s}et-point {a}ngle) mutants with both altered lateral root and shoot orientation show that there are common components in the regulation of growth orientation in the different organs. Rosette leaves and lateral roots also have in common a regulation of positioning by red light. Further molecular and physiological analyses of the GSA mutants will provide insight into the basis of GSA regulation and, thus, a better understanding of how gravity controls plant architecture. [This work was

  6. The Arabidopsis thaliana isogene NIT4 and its orthologs in tobacco encode beta-cyano-L-alanine hydratase/nitrilase.

    PubMed

    Piotrowski, M; Schönfelder, S; Weiler, E W

    2001-01-26

    Nitrilases (nitrile aminohydrolases, EC ) are enzymes that catalyze the hydrolysis of nitriles to the corresponding carbon acids. Among the four known nitrilases of Arabidopsis thaliana, the isoform NIT4 is the most divergent one, and homologs of NIT4 are also known from species not belonging to the Brassicaceae like Nicotiana tabacum and Oryza sativa. We expressed A. thaliana NIT4 as hexahistidine tag fusion protein in Escherichia coli. The purified enzyme showed a strong substrate specificity for beta-cyano-l-alanine (Ala(CN)), an intermediate product of cyanide detoxification in higher plants. Interestingly, not only aspartic acid but also asparagine were identified as products of NIT4-catalyzed Ala(CN) hydrolysis. Asn itself was no substrate for NIT4, indicating that it is not an intermediate but one of two reaction products. NIT4 therefore has both nitrilase and nitrile hydratase activity. Several lines of evidence indicate that the catalytic center for both reactions is the same. The NIT4 homologs of N. tabacum were found to catalyze the same reactions and protein extracts of A. thaliana, N. tabacum and Lupinus angustifolius also converted Ala(CN) to Asp and Asn in vitro. NIT4 may play a role in cyanide detoxification during ethylene biosynthesis because extracts from senescent leaves of A. thaliana showed higher Ala(CN) hydratase/nitrilase activities than extracts from nonsenescent tissue.

  7. Hyperspectral remote sensing applications for monitoring and stress detection in cultural plants: viral infections in tobacco plants

    NASA Astrophysics Data System (ADS)

    Krezhova, Dora; Petrov, Nikolai; Maneva, Svetla

    2012-09-01

    The objectives of this study were to reveal the presence of viral infections in two varieties of tobacco plants (Nicotiana tabacum L.) as well as to discriminate the levels of the disease using hyperspectral leaf reflectance. Data sets were collected from two tobacco cultivars, Xanthi and Rustica, known as most widespread in Bulgaria. Experimental plants were grown in a greenhouse under controlled conditions. At growth stage 4-6 expanded leaf plants of cultivar Xanthi were inoculated with Potato virus Y (PVY) while the Rustica plants were inoculated with Tomato spotted wilt virus (TSWV). These two viruses are worldwide distributed and cause significant yield losses in many economically important crops. In the course of time after inoculation the concentration of the viruses in plant leaves was assessed by erological analysis via DAS-ELISA and RT-PCR techniques. Hyperspectral reflectance data were collected by a portable fibreoptics spectrometer in the visible and near-infrared spectral ranges (450-850 nm). As control plants healthy untreated tobacco plants were used. The significance of the differences between reflectance spectra of control and infected leaves was analyzed by means of Student's t-criterion at p<0.05. The analyses were performed at ten wavebands selected to cover the green (520-580 nm), red (640-680 nm), red edge (690-720 nm) and near infrared (720-780 nm) spectral ranges. Changes in SRC were found for both viral treatments and comparative analysis showed that the influence of PVY was stronger. The discrimination of disease intensity was achieved by derivative analysis of the red edge position.

  8. Deregulation of apoplastic polyamine oxidase affects development and salt response of tobacco plants.

    PubMed

    Gémes, Katalin; Mellidou, Ιfigeneia; Karamanoli, Katerina; Beris, Despoina; Park, Ky Young; Matsi, Theodora; Haralampidis, Kosmas; Constantinidou, Helen-Isis; Roubelakis-Angelakis, Kalliopi A

    2017-04-01

    Polyamine (PA) homeostasis is associated with plant development, growth and responses to biotic/abiotic stresses. Apoplastic PA oxidase (PAO) catalyzes the oxidation of PAs contributing to cellular homeostasis of reactive oxygen species (ROS) and PAs. In tobacco, PAs decrease with plant age, while apoplastic PAO activity increases. Our previous results with young transgenic tobacco plants with enhanced/reduced apoplastic PAO activity (S-ZmPAO/AS-ZmPAO, respectively) established the importance of apoplastic PAO in controlling tolerance to short-term salt stress. However, it remains unclear if the apoplastic PAO pathway is important for salt tolerance at later stages of plant development. In this work, we examined whether apoplastic PAO controls also plant development and tolerance of adult plants during long-term salt stress. The AS-ZmPAO plants contained higher Ca(2+) during salt stress, showing also reduced chlorophyll content index (CCI), leaf area and biomass but taller phenotype compared to the wild-type plants during salt. On the contrary, the S-ZmPAO had more leaves with slightly greater size compared to the AS-ZmPAO and higher antioxidant genes/enzyme activities. Accumulation of proline in the roots was evident at prolonged stress and correlated negatively with PAO deregulation as did the transcripts of genes mediating ethylene biosynthesis. In contrast to the strong effect of apoplastic PAO to salt tolerance in young plants described previously, the effect it exerts at later stages of development is rather moderate. However, the different phenotypes observed in plants deregulating PAO reinforce the view that apoplastic PAO exerts multifaceted roles on plant growth and stress responses. Our data suggest that deregulation of the apoplastic PAO can be further examined as a potential approach to breed plants with enhanced/reduced tolerance to abiotic stress with minimal associated trade-offs.

  9. Regulation of flooding tolerance of SAG12:ipt Arabidopsis plants by cytokinin.

    PubMed

    Huynh, Le Nguyen; Vantoai, Tara; Streeter, John; Banowetz, Gary

    2005-05-01

    A SAG12:ipt gene construct, which increases cytokinin biosynthesis in response to senescence, was introduced into Arabidopsis plants to delay senescence induced by flooding stress. Two forms of flooding stress, including total submergence and root waterlogging, were applied to SAG12:ipt (IPT) and wild-type (WT) plants for 1, 3, and 5 d. A separate experiment compared the recovery of WT and IPT plants subjected to flooding stress. Biomass accumulation, carbohydrate and chlorophyll contents, and cytokinin and abscisic acid were quantified to compare genotypic responses to flooding stress and post-flooding recovery. Real-time RT-PCR studies were performed to quantify ipt and SAG12 gene expression. IPT plants exposed to waterlogging accumulated greater quantities of cytokinins more rapidly than WT plants or those exposed to total submergence. Cytokinin accumulation was accompanied by phenotypic adaptations, including chlorophyll retention and increased biomass and carbohydrate content relative to WT plants. Abscisic acid accumulated rapidly in WT and IPT plants under waterlogging stress but remained low in all genotypes exposed to total submergence. IPT plants showed improved recovery after waterlogging stress was removed. Expression of ipt in submerged plants did not result in cytokinin accumulation until submergence stress was removed. At that point, IPT plants accumulated greater quantities of cytokinin and recovered to a greater extent than WT plants. This study established the relationship between flooding tolerance and cytokinin accumulation in IPT plants and suggested that translation of ipt transcripts and subsequent cytokinin accumulation were delayed under submergence stress.

  10. Nighttime Sugar Starvation Orchestrates Gibberellin Biosynthesis and Plant Growth in Arabidopsis[W

    PubMed Central

    Paparelli, Eleonora; Parlanti, Sandro; Gonzali, Silvia; Novi, Giacomo; Mariotti, Lorenzo; Ceccarelli, Nello; van Dongen, Joost T.; Kölling, Katharina; Zeeman, Samuel C.; Perata, Pierdomenico

    2013-01-01

    A plant’s eventual size depends on the integration of its genetic program with environmental cues, which vary on a daily basis. Both efficient carbon metabolism and the plant hormone gibberellin are required to guarantee optimal plant growth. Yet, little is known about the interplay between carbon metabolism and gibberellins that modulates plant growth. Here, we show that sugar starvation in Arabidopsis thaliana arising from inefficient starch metabolism at night strongly reduces the expression of ent-kaurene synthase, a key regulatory enzyme for gibberellin synthesis, the following day. Our results demonstrate that plants integrate the efficiency of photosynthesis over a period of days, which is transduced into a daily rate of gibberellin biosynthesis. This enables a plant to grow to a size that is compatible with its environment. PMID:24096343

  11. Mighty Dwarfs: Arabidopsis Autoimmune Mutants and Their Usages in Genetic Dissection of Plant Immunity

    PubMed Central

    van Wersch, Rowan; Li, Xin; Zhang, Yuelin

    2016-01-01

    Plants lack the adaptive immune system possessed by mammals. Instead they rely on innate immunity to defend against pathogen attacks. Genomes of higher plants encode a large number of plant immune receptors belonging to different protein families, which are involved in the detection of pathogens and activation of downstream defense pathways. Plant immunity is tightly controlled to avoid activation of defense responses in the absence of pathogens, as failure to do so can lead to autoimmunity that compromises plant growth and development. Many autoimmune mutants have been reported, most of which are associated with dwarfism and often spontaneous cell death. In this review, we summarize previously reported Arabidopsis autoimmune mutants, categorizing them based on their functional groups. We also discuss how their obvious morphological phenotypes make them ideal tools for epistatic analysis and suppressor screens, and summarize genetic screens that have been carried out in various autoimmune mutant backgrounds. PMID:27909443

  12. Phenotypic alterations in Arabidopsis thaliana plants caused by Rhodococcus fascians infection.

    PubMed

    de O Manes, Carmem-Lara; Beeckman, Tom; Ritsema, Tita; Van Montagu, Marc; Goethals, Koen; Holsters, Marcelle

    2004-04-01

    Arabidopsis thaliana (L.) Heynh. plants were challenged with Rhodococcus fascians at several developmental stages and using different inoculation procedures. A variety of morphological alterations was scored on the infected plants; some of them resembled phenotypes of A. thaliana mutants in their shoot apical meristem (SAM) organization. Infection with R. fascians did not affect SAM organization in wild type nor in SAM mutants. Anatomical studies on the new organs formed after infection with R. fascians demonstrated extensive bacterial colonization. Colonization and concomitant production of specific signals are the likely cause of malformations.

  13. Arabidopsis late blight: infection of a nonhost plant by Albugo laibachii enables full colonization by Phytophthora infestans.

    PubMed

    Belhaj, Khaoula; Cano, Liliana M; Prince, David C; Kemen, Ariane; Yoshida, Kentaro; Dagdas, Yasin F; Etherington, Graham J; Schoonbeek, Henk-Jan; van Esse, H Peter; Jones, Jonathan D G; Kamoun, Sophien; Schornack, Sebastian

    2017-01-01

    The oomycete pathogen Phytophthora infestans causes potato late blight, and as a potato and tomato specialist pathogen, is seemingly poorly adapted to infect plants outside the Solanaceae. Here, we report the unexpected finding that P. infestans can infect Arabidopsis thaliana when another oomycete pathogen, Albugo laibachii, has colonized the host plant. The behaviour and speed of P. infestans infection in Arabidopsis pre-infected with A. laibachii resemble P. infestans infection of susceptible potato plants. Transcriptional profiling of P. infestans genes during infection revealed a significant overlap in the sets of secreted-protein genes that are induced in P. infestans upon colonization of potato and susceptible Arabidopsis, suggesting major similarities in P. infestans gene expression dynamics on the two plant species. Furthermore, we found haustoria of A. laibachii and P. infestans within the same Arabidopsis cells. This Arabidopsis-A. laibachii-P. infestans tripartite interaction opens up various possibilities to dissect the molecular mechanisms of P. infestans infection and the processes occurring in co-infected Arabidopsis cells.

  14. Tobacco overexpressing β-ocimene induces direct and indirect responses against aphids in receiver tomato plants.

    PubMed

    Cascone, Pasquale; Iodice, Luigi; Maffei, Massimo E; Bossi, Simone; Arimura, Gen-Ichiro; Guerrieri, Emilio

    2015-01-15

    In the last decade plant-to-plant communication has received an increasing attention, particularly for the role of Volatile Organic Compounds as possible elicitors of plant defense. The role of β-ocimene as an interspecific elicitor of plant defense has been recently assessed in multitrophic systems including different plant species (Solanaceae, Poaceae, legumes) and different pest species including chewer insects and phytophagous mites. Both chewer insects and phytophagous mites are known to elicit specific plant defensive pathways which are different (at least in part) from those elicited by sap feeders. The aim of this research was to fill this gap of knowledge and to assess the role of β-ocimene as an elicitor of plant defense against aphid pests, which are sap feeders. For this purpose we used as transgenic tobacco plant releasing an odour plume enriched in this compound as emitter and a tomato plant as receiver. We selected the aphid Macrosiphum euphorbiae and its natural enemy, the parasitoid Aphidius ervi, as the targets of plant induced defense. Tomato plant defense induced by β-ocimene was assessed by characterizing the aphid performance in terms of fixing behaviour, development and reproduction (direct plant defense) and the parasitoid performance in terms of attraction towards tomato plants (indirect plant defense). The characterization of tomato response to β-ocimene was completed by the identification of Volatile Organic Compounds as released by conditioned tomato plants. Tomato plants that were exposed to the volatiles of transgenic tobacco enriched in β-ocimene resulted in less suitable for the aphids in respect to control ones (direct defense). On tomato plants "elicited" by β-ocimene we recorded: a significant lower number of aphids settled; a significant lower number newborn nymphs; a significant lower weight of aphids feeding. In addition, tomato plants "elicited" by β-ocimene resulted became more attractive towards the parasitoid A. ervi

  15. [Transgenic plant regeneration of tobacco (Nicotiana tabacum) haboring mammalian cyp2e1 gene].

    PubMed

    Li, Peihan; Xiang, Taihe; Xie, Jun; Feng, Ting; Lu, Wenyi

    2012-10-01

    CYP2E1 enzyme encoded by cyp2e1 gene plays an important role in metabolism of heterogeneous organics in mammalian liver cells. The transgenic plant with cyp2e1 can metabolize various low molecular weight organic pollutants. However, it is unclear the mechanism of expression control of cyp2e1 in transgenic plant. In this study, plasmid pSLD50-6 with cyp2e1 and pKH200 with gus as control were transformed into Agrobacterium tumefaciens GV3101 separately. Then, the cyp2e1 or gus genes were transferred into tobacco (Nicotiana tabacum) and the transgenic plants were regenerated via Agrobacterium tumefaciens method. Real-time quantitative PCR (qRT-PCR) was used to analyze the cyp2e1 gene expression. The expression of cyp2e1 in transgenic tobacco with cyp2e1 decreased obviously treated by ethyl alcohol and reduced slightly by benzene and toluene, while it enhanced by acetone, formaldehyde and oxygen deficit in different levels. In addition, the gene expression of NADPH-P450 oxidoreductase and cytochrome b5 enzyme in the transgenic tobacco with cyp2e1 were increased significantly treated by benzene, which showed that NADPH-P450 oxidoreductase and cytochrome b5 enzyme in transgenic tobacco have relation with CYP2E1 detoxication process. It suggested that the NADPH-P450 oxidoreductase and cytochrome b5 enzyme in transgenic plant formed the requirement in mammalian and participated in the electron transport chain of CYP2E1 enzyme catalytic process.

  16. PATELLINS are regulators of auxin-mediated PIN1 relocation and plant development in Arabidopsis thaliana.

    PubMed

    Tejos, Ricardo; Rodriguez-Furlán, Cecilia; Adamowski, Maciej; Sauer, Michael; Norambuena, Lorena; Friml, Jiří

    2017-07-07

    Coordinated cell polarization in developing tissues is a recurrent theme in multicellular organisms. In plants, a directional distribution of the plant hormone auxin is at the core of many developmental programs. A feedback regulation of auxin on the polarized localization of PIN auxin transporters in individual cells has been proposed as a self-organizing mechanism for coordinated tissue polarization, but the molecular mechanisms linking auxin signalling to PIN-dependent auxin transport remain unknown. We used a microarray-based approach to find regulators of the auxin-induced PIN relocation in Arabidopsis thaliana root, and identified a subset of a family of phosphatidylinositol transfer proteins (PITPs), the PATELLINs (PATLs). Here, we show that PATLs are expressed in partially overlapping cell types in different tissues going through mitosis or initiating differentiation programs. PATLs are plasma membrane-associated proteins accumulated in Arabidopsis embryos, primary roots, lateral root primordia and developing stomata. Higher order patl mutants display reduced PIN1 repolarization in response to auxin, shorter root apical meristem, and drastic defects in embryo and seedling development. This suggests that PATLs play a redundant and crucial role in polarity and patterning in Arabidopsis. © 2017. Published by The Company of Biologists Ltd.

  17. Functional Analysis of the Arabidopsis TETRASPANIN Gene Family in Plant Growth and Development1[OPEN

    PubMed Central

    Wang, Feng; Muto, Antonella; Van de Velde, Jan; Neyt, Pia; Himanen, Kristiina; Vandepoele, Klaas; Van Lijsebettens, Mieke

    2015-01-01

    TETRASPANIN (TET) genes encode conserved integral membrane proteins that are known in animals to function in cellular communication during gamete fusion, immunity reaction, and pathogen recognition. In plants, functional information is limited to one of the 17 members of the Arabidopsis (Arabidopsis thaliana) TET gene family and to expression data in reproductive stages. Here, the promoter activity of all 17 Arabidopsis TET genes was investigated by pAtTET::NUCLEAR LOCALIZATION SIGNAL-GREEN FLUORESCENT PROTEIN/β-GLUCURONIDASE reporter lines throughout the life cycle, which predicted functional divergence in the paralogous genes per clade. However, partial overlap was observed for many TET genes across the clades, correlating with few phenotypes in single mutants and, therefore, requiring double mutant combinations for functional investigation. Mutational analysis showed a role for TET13 in primary root growth and lateral root development and redundant roles for TET5 and TET6 in leaf and root growth through negative regulation of cell proliferation. Strikingly, a number of TET genes were expressed in embryonic and seedling progenitor cells and remained expressed until the differentiation state in the mature plant, suggesting a dynamic function over developmental stages. The cis-regulatory elements together with transcription factor-binding data provided molecular insight into the sites, conditions, and perturbations that affect TET gene expression and positioned the TET genes in different molecular pathways; the data represent a hypothesis-generating resource for further functional analyses. PMID:26417009

  18. Plant growth in Arabidopsis is assisted by compost soil-derived microbial communities

    PubMed Central

    Carvalhais, Lilia C.; Muzzi, Frederico; Tan, Chin-Hong; Hsien-Choo, Jin; Schenk, Peer M.

    2013-01-01

    Plants in natural and agricultural environments are continuously exposed to a plethora of diverse microorganisms resulting in microbial colonization of roots and the rhizosphere. This process is believed to be accompanied by an intricate network of ongoing simultaneous interactions. In this study, we examined Arabidopsis thaliana roots and shoots in the presence or absence of whole microbial communities extracted from compost soil. The results show a clear growth promoting effect on Arabidopsis shoots in the presence of soil microbes compared to plants grown in microbe-free soil under otherwise identical conditions. Element analyses showed that iron uptake was facilitated by these mixed microbial communities which also led to transcriptional downregulation of genes required for iron transport. In addition, soil microbial communities suppressed the expression of marker genes involved in nitrogen uptake, oxidative stress/redox signaling, and salicylic acid (SA)-mediated plant defense while upregulating jasmonate (JA) signaling, cell wall organization/biosynthesis and photosynthesis. Multi-species analyses such as simultaneous transcriptional profiling of plants and their interacting microorganisms (metatranscriptomics) coupled to metagenomics may further increase our understanding of the intricate networks underlying plant-microbe interactions. PMID:23847639

  19. Direct Conjugation of Emerging Contaminants in Arabidopsis: Indication for an Overlooked Risk in Plants?

    PubMed

    Fu, Qiuguo; Zhang, Jianbo; Borchardt, Dan; Schlenk, Daniel; Gan, Jay

    2017-06-06

    Agricultural use of treated wastewater, biosolids, and animal wastes introduces a multitude of contaminants of emerging concerns (CECs) into the soil-plant system. The potential for food crops to accumulate CECs depends largely on their metabolism in plants, which at present is poorly understood. Here, we evaluated the metabolism of naproxen and ibuprofen, two of the most-used human drugs from the Profen family, in Arabidopsis thaliana cells and the Arabidopsis plant. The complementary use of high-resolution mass spectrometry and (14)C labeling allowed the characterization of both free and conjugated metabolites, as well as nonextractable residues. Naproxen and ibuprofen, in their parent form, were conjugated quickly and directly with glutamic acid and glutamine, and further with peptides, in A. thaliana cells. For example, after 120 h, the metabolites of naproxen accounted for >90% of the extractable chemical mass, while the intact parent itself was negligible. The structures of glutamate and glutamine conjugates were confirmed using synthesized standards and further verified in whole plants. Amino acid conjugates may easily deconjugate, releasing the parent molecule. This finding highlights the possibility that the bioactivity of such CECs may be effectively preserved through direct conjugation, a previously overlooked risk. Many other CECs are also carboxylic acids, such as the profens. Therefore, direct conjugation may be a common route for plant metabolism of these CECs, making it imperative to consider conjugates when assessing their risks.

  20. 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.

  1. Transcriptome analysis of reproductive-stage Arabidopsis plants exposed gamma-ray irradiation at various doses.

    PubMed

    Hwang, Sun-Goo; Kim, Dong Sub; Kim, Jin-Baek; Hwang, Jung Eun; Park, Hyun Mi; Kim, Jin Hyuk; Jang, Cheol Seong

    2016-08-01

    Gamma rays (GR) induce significant changes in the structure and expression of genes involved in the regulation of diverse biochemical and physiological processes. Arabidopsis plants exhibit different growth and development patterns in response to exposure to GR. The effects on gene expression of different radiation doses of GR (100 and 800 Gy) administered to Arabidopsis plants were examined at the reproductive stage. We irradiated 26-day-old plants with three replications [developmental stages 5.1-6.0, according to Boyes et al. ( 2001 )] using a GR irradiator (60 Co, ca. 150 TBq capacity, Atomic Energy of Canada Limited, Ontario, Canada) at the Korea Atomic Energy Research Institute. Plants were treated with 100, 200, 300, 400, 800, 1200, 1600, or 2000 Gy, and the doses were made from varying the distance to the source. We conducted a high-throughput screening analysis and detected 883 GR-responsive genes that showed significant changes; these were involved in several putative metabolic pathways related to biotic stress. Additionally, five overrepresented cis-regulatory elements were identified in the 1-kb upstream regions of GR-responsive genes by using motif enrichment analysis. We also detected three GR-responsive genes associated with stamen development and confirmed their co-regulation with functionally interacting genes. This finding suggests that a network-based analysis is a viable approach to identify significant GR-responsive genes associated with the reproductive stage of Arabidopsis. Our results provide further insights into the complex biological systems involved in the response to different doses of GR in plants.

  2. Is chloroplast movement in tobacco plants influenced systemically after local illumination or burning stress?

    PubMed

    Naus, Jan; Rolencová, Monika; Hlavácková, Vladimíra

    2008-10-01

    Chloroplast movement has been studied in many plants mainly in relation to the local light, mechanical or stress effects. Here we investigated possible systemic responses of chloroplast movement to local light or burning stress in tobacco plants (Nicotiana tabacum cv. Samsun). Chloroplast movement was measured using two independent methods: one with a SPAD 502 Chlorophyll meter and another by collimated transmittance at a selected wavelength (676 nm). A sensitive periodic movement of chloroplasts was used in high or low (2 000 or 50 micromol/m(2) per s photosynthetically active radiation, respectively) cold white light with periods of 50 or 130 min. Measurements were carried out in the irradiated area, in the non-irradiated area of the same leaf or in the leaf located on the stem below the irradiated or burned one. No significant changes in systemic chloroplast movement in non-irradiated parts of the leaf and in the non-treated leaf were detected. Our data indicate that chloroplast movement in tobacco is dependent dominantly on the intensity and spectral composition of the incident light and on the local stimulation and state of the target tissue. No systemic signal was strong enough to evoke a detectable systemic response in chloroplast movement in distant untreated tissues of tobacco plants.

  3. Transgenic tobacco plants that overexpress alfalfa NADH-glutamate synthase have higher carbon and nitrogen content.

    PubMed

    Chichkova, S; Arellano, J; Vance, C P; Hernández, G

    2001-11-01

    This work reports the characterization of transgenic tobacco (Nicotiana tabacum L.) plants that constitutively overexpress NADH-GOGAT. Three independent transformants, designated GOS10, GOS13 and GOS19 (for GOGAT sense), with stable integration of the chimeric alfalfa NADH-GOGAT gene fused to the CaMV 35S promoter were studied. The transgene was stably integrated and inherited by the progeny. In these GOS lines, the expression of NADH-GOGAT mRNA and protein was detected at low levels in roots and leaves, while the expression of the host tobacco NADH-GOGAT gene was nearly undetectable. The roots of GOS lines showed an elevated (15-40%) enzyme activity as compared to control plants. When GOS plants were grown under greenhouse conditions and fed with either nitrate or ammonium as the sole nitrogen source, they showed higher total carbon and nitrogen content in shoots and increased shoot dry weight when plants were entering into the flowering stage, as compared to control plants. The observed phenotype of GOS plants was interpreted as reflecting a higher capacity to assimilate nitrogen due to a higher NADH-GOGAT activity.

  4. Enhanced Transformation of TNT by Arabidopsis Plants Expressing an Old Yellow Enzyme

    PubMed Central

    Zhu, Bo; Peng, Ri-He; Fu, Xiao-Yan; Jin, Xiao-Fen; Zhao, Wei; Xu, Jing; Han, Hong-Juan; Gao, Jian-Jie; Xu, Zhi-Sheng; Bian, Lin; Yao, Quan-Hong

    2012-01-01

    2,4,6-Trinitrotoluene (TNT) is released in nature from manufacturing or demilitarization facilities, as well as after the firing or detonation of munitions or leakage from explosive remnants of war. Environmental contamination by TNT is associated with human health risks, necessitating the development of cost-effective remediation techniques. The lack of affordable and effective cleanup technologies for explosives contamination requires the development of better processes. In this study, we present a system for TNT phytoremediation by overexpressing the old yellow enzyme (OYE3) gene from Saccharomyces cerevisiae. The resulting transgenic Arabidopsis plants demonstrated significantly enhanced TNT tolerances and a strikingly higher capacity to remove TNT from their media. The current work indicates that S. cerevisiae OYE3 overexpression in Arabidopsis is an efficient method for the phytoremoval and degradation of TNT. Our findings have the potential to provide a suitable remediation strategy for sites contaminated by TNT. PMID:22808068

  5. Building a plant: cell fate specification in the early Arabidopsis embryo.

    PubMed

    ten Hove, Colette A; Lu, Kuan-Ju; Weijers, Dolf

    2015-02-01

    Embryogenesis is the beginning of plant development, yet the cell fate decisions and patterning steps that occur during this time are reiterated during development to build the post-embryonic architecture. In Arabidopsis, embryogenesis follows a simple and predictable pattern, making it an ideal model with which to understand how cellular and tissue developmental processes are controlled. Here, we review the early stages of Arabidopsis embryogenesis, focusing on the globular stage, during which time stem cells are first specified and all major tissues obtain their identities. We discuss four different aspects of development: the formation of outer versus inner layers; the specification of vascular and ground tissues; the determination of shoot and root domains; and the establishment of the first stem cells. © 2015. Published by The Company of Biologists Ltd.

  6. A study on the influence of different promoter and 5'UTR (URM) cassettes from Arabidopsis thaliana on the expression level of the reporter gene β glucuronidase in tobacco and cotton.

    PubMed

    Agarwal, Parul; Garg, Varsha; Gautam, Taru; Pillai, Beena; Kanoria, Shaveta; Burma, Pradeep Kumar

    2014-04-01

    Several reports of promoters from plants, viral and artificial origin that confer high constitutive expression are known. Among these the CaMV 35S promoter is used extensively for transgene expression in plants. We identified candidate promoters from Arabidopsis based on their transcript levels (meta-analysis of available microarray control datasets) to test their activity in comparison to the CaMV 35S promoter. A set of 11 candidate genes were identified which showed high transcript levels in the aerial tissue (i.e. leaf, shoot, flower and stem). In the initial part of the study binary vectors were developed wherein the promoter and 5'UTR region of these candidate genes (Upstream Regulatory Module, URM) were cloned upstream to the reporter gene β glucuronidase (gus). The promoter strengths were tested in transformed callus of Nicotiana tabacum and Gossypium hirsutum. On the basis of the results obtained from the callus, the influence of the URM cassettes on transgene expression was tested in transgenic tobacco. The URM regions of the genes encoding a subunit of photosystem I (PHOTO) and geranyl geranyl reductase (GGR) in A. thaliana genome showed significantly high levels of GUS activity in comparison to the CaMV 35S promoter. Further, when the 5'UTRs of both the genes were placed downstream to the CaMV 35S promoter it led to a substantial increase in GUS activity in transgenic tobacco lines and cotton callus. The enhancement observed was even higher to that observed with the viral leader sequences like Ω and AMV, known translational enhancers. Our results indicate that the two URM cassettes or the 5'UTR regions of PHOTO and GGR when placed downstream to the CaMV 35S promoter can be used to drive high levels of transgene expression in dicotyledons.

  7. Tobacco mosaic virus infection results in an increase in recombination frequency and resistance to viral, bacterial, and fungal pathogens in the progeny of infected tobacco plants.

    PubMed

    Kathiria, Palak; Sidler, Corinne; Golubov, Andrey; Kalischuk, Melanie; Kawchuk, Lawrence M; Kovalchuk, Igor

    2010-08-01

    Our previous experiments showed that infection of tobacco (Nicotiana tabacum) plants with Tobacco mosaic virus (TMV) leads to an increase in homologous recombination frequency (HRF). The progeny of infected plants also had an increased rate of rearrangements in resistance gene-like loci. Here, we report that tobacco plants infected with TMV exhibited an increase in HRF in two consecutive generations. Analysis of global genome methylation showed the hypermethylated genome in both generations of plants, whereas analysis of methylation via 5-methyl cytosine antibodies demonstrated both hypomethylation and hypermethylation. Analysis of the response of the progeny of infected plants to TMV, Pseudomonas syringae, or Phytophthora nicotianae revealed a significant delay in symptom development. Infection of these plants with TMV or P. syringae showed higher levels of induction of PATHOGENESIS-RELATED GENE1 gene expression and higher levels of callose deposition. Our experiments suggest that viral infection triggers specific changes in progeny that promote higher levels of HRF at the transgene and higher resistance to stress as compared with the progeny of unstressed plants. However, data reported in these studies do not establish evidence of a link between recombination frequency and stress resistance.

  8. Overexpression of Nictaba-Like Lectin Genes from Glycine max Confers Tolerance toward Pseudomonas syringae Infection, Aphid Infestation and Salt Stress in Transgenic Arabidopsis Plants

    PubMed Central

    Van Holle, Sofie; Smagghe, Guy; Van Damme, Els J. M.

    2016-01-01

    Plants have evolved a sophisticated immune system that allows them to recognize invading pathogens by specialized receptors. Carbohydrate-binding proteins or lectins are part of this immune system and especially the lectins that reside in the nucleocytoplasmic compartment are known to be implicated in biotic and abiotic stress responses. The class of Nictaba-like lectins (NLL) groups all proteins with homology to the tobacco (Nicotiana tabacum) lectin, known as a stress-inducible lectin. Here we focus on two Nictaba homologs from soybean (Glycine max), referred to as GmNLL1 and GmNLL2. Confocal laser scanning microscopy of fusion constructs with the green fluorescent protein either transiently expressed in Nicotiana benthamiana leaves or stably transformed in tobacco BY-2 suspension cells revealed a nucleocytoplasmic localization for the GmNLLs under study. RT-qPCR analysis of the transcript levels for the Nictaba-like lectins in soybean demonstrated that the genes are expressed in several tissues throughout the development of the plant. Furthermore, it was shown that salt treatment, Phytophthora sojae infection and Aphis glycines infestation trigger the expression of particular NLL genes. Stress experiments with Arabidopsis lines overexpressing the NLLs from soybean yielded an enhanced tolerance of the plant toward bacterial infection (Pseudomonas syringae), insect infestation (Myzus persicae) and salinity. Our data showed a better performance of the transgenic lines compared to wild type plants, indicating that the NLLs from soybean are implicated in the stress response. These data can help to further elucidate the physiological importance of the Nictaba-like lectins from soybean, which can ultimately lead to the design of crop plants with a better tolerance to changing environmental conditions. PMID:27826309

  9. The expression of tomato prosystemin gene in tobacco plants highly affects host proteomic repertoire.

    PubMed

    Rocco, Mariapina; Corrado, Giandomenico; Arena, Simona; D'Ambrosio, Chiara; Tortiglione, Claudia; Sellaroli, Stefano; Marra, Mauro; Rao, Rosa; Scaloni, Andrea

    2008-07-21

    Systemin, an octadecapeptide isolated from tomato, is a primary signal molecule involved in the local and systemic responses to pest attack, elicited by activation of a set of defence genes. It derives from processing of prosystemin, a prohormone of almost 200 amino acids. Prosystemin orthologues have been found in other Solanaceae species but not in tobacco, where are present hydroxyproline-rich peptides functionally but not structurally related to tomato systemin. Molecular events leading to the release of signalling peptides from protein precursors are unknown in plants; the occurrence of a family of signal molecules suggests that initiation of wound response may involve different processing mechanisms. It has been previously shown that the protein product from an engineered tomato prosystemin gene is processed in tobacco, thus suggesting that the components responsible for its post-translational modifications are present in this species. By analyzing analysing the proteome repertoire of transformed tobacco plant leaves with 2-DE, here we demonstrate that the constitutive expression of the tomato prosystemin gene highly affected host protein synthesis. In particular, engineered plants showed a number of differentially synthesized proteins that were identified by PMF MALDI-TOF and microLC-ESI-IT-MS/MS experiments as polypeptide species involved in protection from pathogens and oxidative stress, or in carbon/energy metabolism. Significant differences in over-produced proteins were observed with respect to previous data reported on systemin-engineered tomato plants. Our results strongly support the need of using proteomic approaches during systematic analysis of plant tissues to investigate the principle of substantial equivalence in transgenic plants expressing a transgene coding for a signalling molecule.

  10. Grapevine and Arabidopsis Cation-Chloride Cotransporters Localize to the Golgi and Trans-Golgi Network and Indirectly Influence Long-Distance Ion Transport and Plant Salt Tolerance1[OPEN

    PubMed Central

    Henderson, Sam W.; Wege, Stefanie; Qiu, Jiaen; Blackmore, Deidre H.; Walker, Amanda R.; Tyerman, Stephen D.; Walker, Rob R.; Gilliham, Matthew

    2015-01-01

    Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. They are predicted to improve shoot salt exclusion by directly catalyzing the retrieval of sodium (Na+) and chloride (Cl−) ions from the root xylem. We investigated whether grapevine (Vitis vinifera [Vvi]) CCC has a role in salt tolerance by cloning and functionally characterizing the gene from the cultivar Cabernet Sauvignon. Amino acid sequence analysis revealed that VviCCC shares a high degree of similarity with other plant CCCs. A VviCCC-yellow fluorescent protein translational fusion protein localized to the Golgi and the trans-Golgi network and not the plasma membrane when expressed transiently in tobacco (Nicotiana benthamiana) leaves and Arabidopsis (Arabidopsis thaliana) mesophyll protoplasts. AtCCC-green fluorescent protein from Arabidopsis also localized to the Golgi and the trans-Golgi network. In Xenopus laevis oocytes, VviCCC targeted to the plasma membrane, where it catalyzed bumetanide-sensitive 36Cl–, 22Na+, and 86Rb+ uptake, suggesting that VviCCC (like AtCCC) belongs to the Na+-K+-2Cl– cotransporter class of CCCs. Expression of VviCCC in an Arabidopsis ccc knockout mutant abolished the mutant’s stunted growth phenotypes and reduced shoot Cl– and Na+ content to wild-type levels after growing plants in 50 mm NaCl. In grapevine roots, VviCCC transcript abundance was not regulated by Cl– treatment and was present at similar levels in both the root stele and cortex of three Vitis spp. genotypes that exhibit differential shoot salt exclusion. Our findings indicate that CCC function is conserved between grapevine and Arabidopsis, but neither protein is likely to directly mediate ion transfer with the xylem or have a direct role in salt tolerance. PMID:26378102

  11. Arabidopsis thaliana: A Model Host Plant to Study Plant-Pathogen Interaction Using Rice False Smut Isolates of Ustilaginoidea virens.

    PubMed

    Andargie, Mebeaselassie; Li, Jianxiong

    2016-01-01

    Rice false smut fungus which is a biotrophic fungal pathogen causes an important rice disease and brings a severe damage where rice is cultivated. We established a new fungal-plant pathosystem where Ustilaginoidea virens was able to interact compatibly with the model plant Arabidopsis thaliana. Disease symptoms were apparent on the leaves of the plants after 6 days of post inoculation in the form of chlorosis. Cytological studies showed that U. virens caused a heavy infestation inside the cells of the chlorotic tissues. Development and colonization of aerial mycelia in association with floral organ, particularly on anther and stigma of the flowers after 3 weeks of post inoculation was evident which finally caused infection on the developing seeds and pod tissues. The fungus adopts a uniquely biotrophic infection strategy in roots and spreads without causing a loss of host cell viability. We have also demonstrated that U. virens isolates infect Arabidopsis and the plant subsequently activates different defense response mechanisms which are witnessed by the expression of pathogenesis-related genes, PR-1, PR-2, PR-5, PDF1.1, and PDF1.2. The established A. thaliana-U. virens pathosystem will now permit various follow-up molecular genetics and gene expression experiments to be performed to identify the defense signals and responses that restrict fungal hyphae colonization in planta and also provide initial evidence for tissue-adapted fungal infection strategies.

  12. Transgenic Arabidopsis Plants Expressing Tomato Glutathione S-Transferase Showed Enhanced Resistance to Salt and Drought Stress.

    PubMed

    Xu, Jing; Xing, Xiao-Juan; Tian, Yong-Sheng; Peng, Ri-He; Xue, Yong; Zhao, Wei; Yao, Quan-Hong

    2015-01-01

    Although glutathione S-transferases (GST, EC 2.5.1.18) are involved in response to abiotic stress, limited information is available regarding gene function in tomato. In this study, a GST gene from tomato, designated LeGSTU2, was cloned and functionally characterized. Expression profile analysis results showed that it was expressed in roots and flowers, and the transcription was induced by salt, osmotic, and heat stress. The gene was then introduced to Arabidopsis by Agrobacterium tumefaciens-mediated transformation. Transgenic Arabidopsis plants were normal in terms of growth and maturity compared with wild-type plants. Transgenic plants also showed an enhanced resistance to salt and osmotic stress induced by NaCl and mannitol. The increased tolerance of transgenic plants was correlated with the changes in proline, malondialdehyde and antioxidative emzymes activities. Our results indicated that the gene from tomato plays a positive role in improving tolerance to salinity and drought stresses in Arabidopsis.

  13. Quantitative monitoring of Arabidopsis thaliana growth and development using high-throughput plant phenotyping.

    PubMed

    Arend, Daniel; Lange, Matthias; Pape, Jean-Michel; Weigelt-Fischer, Kathleen; Arana-Ceballos, Fernando; Mücke, Ingo; Klukas, Christian; Altmann, Thomas; Scholz, Uwe; Junker, Astrid

    2016-08-16

    With the implementation of novel automated, high throughput methods and facilities in the last years, plant phenomics has developed into a highly interdisciplinary research domain integrating biology, engineering and bioinformatics. Here we present a dataset of a non-invasive high throughput plant phenotyping experiment, which uses image- and image analysis- based approaches to monitor the growth and development of 484 Arabidopsis thaliana plants (thale cress). The result is a comprehensive dataset of images and extracted phenotypical features. Such datasets require detailed documentation, standardized description of experimental metadata as well as sustainable data storage and publication in order to ensure the reproducibility of experiments, data reuse and comparability among the scientific community. Therefore the here presented dataset has been annotated using the standardized ISA-Tab format and considering the recently published recommendations for the semantical description of plant phenotyping experiments.

  14. Quantitative monitoring of Arabidopsis thaliana growth and development using high-throughput plant phenotyping

    PubMed Central

    Arend, Daniel; Lange, Matthias; Pape, Jean-Michel; Weigelt-Fischer, Kathleen; Arana-Ceballos, Fernando; Mücke, Ingo; Klukas, Christian; Altmann, Thomas; Scholz, Uwe; Junker, Astrid

    2016-01-01

    With the implementation of novel automated, high throughput methods and facilities in the last years, plant phenomics has developed into a highly interdisciplinary research domain integrating biology, engineering and bioinformatics. Here we present a dataset of a non-invasive high throughput plant phenotyping experiment, which uses image- and image analysis- based approaches to monitor the growth and development of 484 Arabidopsis thaliana plants (thale cress). The result is a comprehensive dataset of images and extracted phenotypical features. Such datasets require detailed documentation, standardized description of experimental metadata as well as sustainable data storage and publication in order to ensure the reproducibility of experiments, data reuse and comparability among the scientific community. Therefore the here presented dataset has been annotated using the standardized ISA-Tab format and considering the recently published recommendations for the semantical description of plant phenotyping experiments. PMID:27529152

  15. Significant improvement of stress tolerance in tobacco plants by overexpressing a stress-responsive aldehyde dehydrogenase gene from maize (Zea mays).

    PubMed

    Huang, Weizao; Ma, Xinrong; Wang, Qilin; Gao, Yongfeng; Xue, Ying; Niu, Xiangli; Yu, Guirong; Liu, Yongsheng

    2008-11-01

    Aldehyde dehydrogenases (ALDHs) play a central role in detoxification processes of aldehydes generated in plants when exposed to the stressed conditions. In order to identify genes required for the stresses responses in the grass crop Zea mays, an ALDH (ZmALDH22A1) gene was isolated and characterized. ZmALDH22A1 belongs to the family ALDH22 that is currently known only in plants. The ZmALDH22A1 encodes a protein of 593 amino acids that shares high identity with the orthologs from Saccharum officinarum (95%), Oryza sativa (89%), Triticum aestivum (87%) and Arabidopsis thaliana (77%), respectively. Real-time PCR analysis indicates that ZmALDH22A1 is expressed differentially in different tissues. Various elevated levels of ZmALDH22A1 expression have been detected when the seedling roots exposed to abiotic stresses including dehydration, high salinity and abscisic acid (ABA). Tomato stable transformation of construct expressing the ZmALDH22A1 signal peptide fused with yellow fluorescent protein (YFP) driven by the CaMV35S-promoter reveals that the fusion protein is targeted to plastid. Transgenic tobacco plants overexpressing ZmALDH22A1 shows elevated stresses tolerance. Stresses tolerance in transgenic plants is accompanied by a reduction of malondialdehyde (MDA) derived from cellular lipid peroxidation.

  16. Principal Component Analysis of Chlorophyll Content in Tobacco, Bean and Petunia Plants Exposed to Different Tropospheric Ozone Concentrations

    NASA Astrophysics Data System (ADS)

    Borowiak, Klaudia; Zbierska, Janina; Budka, Anna; Kayzer, Dariusz

    2014-06-01

    Three plant species were assessed in this study - ozone-sensitive and -resistant tobacco, ozone-sensitive petunia and bean. Plants were exposed to ambient air conditions for several weeks in two sites differing in tropospheric ozone concentrations in the growing season of 2009. Every week chlorophyll contents were analysed. Cumulative ozone effects on the chlorophyll content in relation to other meteorological parameters were evaluated using principal component analysis, while the relation between certain days of measurements of the plants were analysed using multivariate analysis of variance. Results revealed variability between plant species response. However, some similarities were noted. Positive relations of all chlorophyll forms to cumulative ozone concentration (AOT 40) were found for all the plant species that were examined. The chlorophyll b/a ratio revealed an opposite position to ozone concentration only in the ozone-resistant tobacco cultivar. In all the plant species the highest average chlorophyll content was noted after the 7th day of the experiment. Afterwards, the plants usually revealed various responses. Ozone-sensitive tobacco revealed decrease of chlorophyll content, and after few weeks of decline again an increase was observed. Probably, due to the accommodation for the stress factor. While during first three weeks relatively high levels of chlorophyll contents were noted in ozone-resistant tobacco. Petunia revealed a slow decrease of chlorophyll content and the lowest values at the end of the experiment. A comparison between the plant species revealed the highest level of chlorophyll contents in ozone-resistant tobacco.

  17. TcCYS4, a cystatin from cocoa, reduces necrosis triggered by MpNEP2 in tobacco plants.

    PubMed

    Santana, L S; Costa, M G C; Pirovani, N M; Almeida, A F; Alvim, F C; Pirovani, C P

    2014-09-26

    In Brazil, most cocoa bean production occurs in Southern Bahia. Witches' broom disease arrived in this area in 1989 and has since caused heavy losses in production. The disease is caused by the basidiomycete fungus Moniliophthora perniciosa, a hemibiotrophic fungus that produces the necrosis and ethylene-inducting protein (MpNEP2) during infection; this protein can activate cysteine proteases and induce programmed cell death. Cysteine proteases can be modulated by cystatin. In this study, we overexpressed TcCYS4, a cocoa cystatin, in tobacco plants and evaluated the effect on MpNEP2 in model plants. Tccys4 cDNA was cloned into the pCAMBIA 1390 vector and inserted into the tobacco plants via Agrobacterium tumefaciens. Transgene expression was analyzed by reverse transcription-quantitative PCR and Western blot analysis. Transcript and protein levels in Tcccys4:tobacco lines were 8.9- and 1.5-fold higher than in wild-type plants (wt). Tcccys4:tobacco lines showed no change in growth compared to wt plants. CO2 net assimilation (A) increased in Tcccys4:tobacco lines compared to wt plants. Only one line showed statistically significant stomatal conductance (gs) and transpiration rate (E) changes. MpNEP2 was infiltered into the foliar mesophyll of Tcccys4:tobacco lines and wt plants, and necrotic lesions were attenuated in lines highly expressing Tccys4. Our results suggest that cocoa cystatin TcCYS4 affects MpNEP2 activity related to the progression of programmed cell death in tobacco plants. This may occur through the action of cystatin to inhibit cysteine proteases activated by MpNEP2 in plant tissues. Further studies are necessary to examine cystatin in the Theobroma cacao-M. perniciosa pathosystem.

  18. A crucial role for the putative Arabidopsis topoisomerase VI in plant growth and development

    PubMed Central

    Yin, Yanhai; Cheong, Hyeonsook; Friedrichsen, Danielle; Zhao, Yunde; Hu, Jianping; Mora-Garcia, Santiago; Chory, Joanne

    2002-01-01

    Plant steroid hormones, brassinosteroids (BRs), play important roles throughout plant growth and development. Plants defective in BR biosynthesis or perception display cell elongation defects and severe dwarfism. Two dwarf mutants named bin3 and bin5 with identical phenotypes to each other display some characteristics of BR mutants and are partially insensitive to exogenously applied BRs. In the dark, bin3 or bin5 seedlings are de-etiolated with short hypocotyls and open cotyledons. Light-grown mutant plants are dwarfs with short petioles, epinastic leaves, short inflorescence stems, and reduced apical dominance. We cloned BIN3 and BIN5 and show that BIN5 is one of three putative Arabidopsis SPO11 homologs (AtSPO11-3) that also shares significant homology to archaebacterial topoisomerase VI (TOP6) subunit A, whereas BIN3 represents a putative eukaryotic homolog of TOP6B. The pleiotropic dwarf phenotypes of bin5 establish that, unlike all of the other SPO11 homologs that are involved in meiosis, BIN5/AtSPO11-3 plays a major role during somatic development. Furthermore, microarray analysis of the expression of about 5500 genes in bin3 or bin5 mutants indicates that about 321 genes are down-regulated in both of the mutants, including 18 of 30 BR-induced genes. These results suggest that BIN3 and BIN5 may constitute an Arabidopsis topoisomerase VI that modulates expression of many genes, including those regulated by BRs. PMID:12119417

  19. Overexpression of Mitochondrial Phosphate Transporter 3 Severely Hampers Plant Development through Regulating Mitochondrial Function in Arabidopsis

    PubMed Central

    Jia, Fengjuan; Wan, Xiaomin; Zhu, Wei; Sun, Dan; Zheng, Chengchao; Liu, Pei; Huang, Jinguang

    2015-01-01

    Mitochondria are abundant and important organelles present in nearly all eukaryotic cells, which maintain metabolic communication with the cytosol through mitochondrial carriers. The mitochondrial membrane localized phosphate transporter (MPT) plays vital roles in diverse development and signaling processes, especially the ATP biosynthesis. Among the three MPT genes in Arabidopsis genome, AtMPT3 was proven to be a major member, and its overexpression gave rise to multiple developmental defects including curly leaves with deep color, dwarfed stature, and reduced fertility. Transcript profiles revealed that genes involved in plant metabolism, cellular redox homeostasis, alternative respiration pathway, and leaf and flower development were obviously altered in AtMPT3 overexpression (OEMPT3) plants. Moreover, OEMPT3 plants also accumulated higher ATP content, faster respiration rate and more reactive oxygen species (ROS) than wild type plants. Overall, our studies showed that AtMPT3 was indispensable for Arabidopsis normal growth and development, and provided new sights to investigate its possible regulation mechanisms. PMID:26076137

  20. The TIP GROWTH DEFECTIVE1 S-acyl transferase regulates plant cell growth in Arabidopsis.

    PubMed

    Hemsley, Piers A; Kemp, Alison C; Grierson, Claire S

    2005-09-01

    TIP GROWTH DEFECTIVE1 (TIP1) of Arabidopsis thaliana affects cell growth throughout the plant and has a particularly strong effect on root hair growth. We have identified TIP1 by map-based cloning and complementation of the mutant phenotype. TIP1 encodes an ankyrin repeat protein with a DHHC Cys-rich domain that is expressed in roots, leaves, inflorescence stems, and floral tissue. Two homologues of TIP1 in yeast (Saccharomyces cerevisiae) and human (Homo sapiens) have been shown to have S-acyl transferase (also known as palmitoyl transferase) activity. S-acylation is a reversible hydrophobic protein modification that offers swift, flexible control of protein hydrophobicity and affects protein association with membranes, signal transduction, and vesicle trafficking within cells. We show that TIP1 binds the acyl group palmitate, that it can rescue the morphological, temperature sensitivity, and yeast casein kinase2 localization defects of the yeast S-acyl transferase mutant akr1Delta, and that inhibition of acylation in wild-type Arabidopsis roots reproduces the Tip1- mutant phenotype. Our results demonstrate that S-acylation is essential for normal plant cell growth and identify a plant S-acyl transferase, an essential research tool if we are to understand how this important, reversible lipid modification operates in plant cells.

  1. Plant growth processes in Arabidopsis under microgravity conditions simulated by a clinostat.

    PubMed

    Ishii, Y; Hoson, T; Kamisaka, S; Miyamoto, K; Ueda, J; Mantani, S; Fujii, S; Masuda, Y; Yamamoto, R

    1996-03-01

    The life cycle of Arabidopsis plants was examined by growing them on a horizontal clinostat. Seeds on agar media were allowed to germinate and seedlings were grown under a simulated microgravity on a horizontal clinostat. Clinorotation (3 rpm) did not appear to interfere with germination of plant seeds and development of cotyledons and leaves. Stress relaxation parameters of the cell wall, the minimum relaxation time and the relaxation rate did not appear to be affected by clinostat rotation. On the other hand, the length of inflorescences was reduced to 61-62% by clinostat rotation. Rotation was found to inhibit the polar transport of auxin, although inflorescence growth and auxin transport were not completely inhibited. From these facts, it is possible that the life cycle in Arabidopsis plants could be accomplished in space, although growth phenomena involving auxin transport and its action may be disturbed. Plants may have a capacity to grow in space and we may be able to cultivate crops in space.

  2. Molecular responses to aphid feeding in Arabidopsis in relation to plant defense pathways.

    PubMed

    Moran, P J; Thompson, G A

    2001-02-01

    Little is known about molecular responses in plants to phloem feeding by insects. The induction of genes associated with wound and pathogen response pathways was investigated following green peach aphid (Myzus persicae) feeding on Arabidopsis. Aphid feeding on rosette leaves induced transcription of two genes associated with salicylic acid (SA)-dependent responses to pathogens (PR-1 and BGL2) 10- and 23-fold, respectively. Induction of PR-1 and BGL2 mRNA was reduced in npr1 mutant plants, which are deficient in SA signaling. Application of the SA analog benzothiadiazole led to decreases in aphid reproduction on leaves of both wild-type plants and mutant plants deficient in responsiveness to SA, suggesting that wild-type SA-dependent responses do not influence resistance to aphids. Two-fold increases occurred in mRNA levels of PDF1.2, which encodes defensin, a peptide involved in the jasmonate (JA)-/ethylene-dependent response pathway. Transcripts encoding JA-inducible lipoxygenase (LOX2) and SA/JA-inducible Phe-ammonia lyase increased 1.5- to 2-fold. PDF1.2 and LOX2 induction by aphids did not occur in infested leaves of the JA-resistant coi1-1 mutant. Aphid feeding induced 10-fold increases in mRNA levels of a stress-related monosaccharide symporter gene, STP4. Phloem feeding on Arabidopsis leads to stimulation of response pathways associated with both pathogen infection and wounding.

  3. Arabidopsis seedling flood-inoculation technique: a rapid and reliable assay for studying plant-bacterial interactions.

    PubMed

    Ishiga, Yasuhiro; Ishiga, Takako; Uppalapati, Srinivasa R; Mysore, Kirankumar S

    2011-10-06

    The Arabidopsis thaliana-Pseudomonas syringae model pathosystem is one of the most widely used systems to understand the mechanisms of microbial pathogenesis and plant innate immunity. Several inoculation methods have been used to study plant-pathogen interactions in this model system. However, none of the methods reported to date are similar to those occurring in nature and amicable to large-scale mutant screens. In this study, we developed a rapid and reliable seedling flood-inoculation method based on young Arabidopsis seedlings grown on MS medium. This method has several advantages over conventional soil-grown plant inoculation assays, including a shorter growth and incubation period, ease of inoculation and handling, uniform infection and disease development, requires less growth chamber space and is suitable for high-throughput screens. In this study we demonstrated the efficacy of the Arabidopsis seedling assay to study 1) the virulence factors of P. syringae pv. tomato DC3000, including type III protein secretion system (TTSS) and phytotoxin coronatine (COR); 2) the effector-triggered immunity; and 3) Arabidopsis mutants affected in salicylic acid (SA)- and pathogen-associated molecular pattern (PAMPs)-mediated pathways. Furthermore, we applied this technique to study nonhost resistance (NHR) responses in Arabidopsis using nonhost pathogens, such as P. syringae pv. tabaci, pv. glycinea and pv. tomato T1, and confirmed the functional role of FLAGELLIN-SENSING 2 (FLS2) in NHR. The Arabidopsis seedling flood-inoculation assay provides a rapid, efficient and economical method for studying Arabidopsis-Pseudomonas interactions with minimal growth chamber space and time. This assay could also provide an excellent system for investigating the virulence mechanisms of P. syringae. Using this method, we demonstrated that FLS2 plays a critical role in conferring NHR against nonhost pathovars of P. syringae, but not to Xanthomonas campestris pv. vesicatoria. This method

  4. Translocation of metal ions from soil to tobacco roots and their concentration in the plant parts.

    PubMed

    da Silva, Cleber Pinto; de Almeida, Thiago E; Zittel, Rosimara; de Oliveira Stremel, Tatiana R; Domingues, Cinthia E; Kordiak, Januário; de Campos, Sandro Xavier

    2016-12-01

    This paper presents a study on the translocation factors (TFs) and bioconcentration factors (BCFs) of copper (Cu), manganese (Mn), zinc (Zn), cobalt (Co), chromium (Cr), cadmium (Cd), lead (Pb), iron (Fe), nickel (Ni), and arsenic (As) ions in roots, stems, and leaves of tobacco. The results revealed that during the tobacco growth, the roots are able to increase the sensitiveness of the physiological control, reducing the translocation of the metals Ni (0.38) and Pb (0.48) to the leaves. Cd and Zn presented factors TF and BCF >1 in the three tissues under analysis, which indicates the high potential for transportation and accumulation of these metals in all plant tissues. The TF values for Cr (0.65) and As (0.63) revealed low translocation of these ions to the aerial parts, indicating low mobility of ions from the roots. Therefore, tobacco can be considered an efficient accumulator of Ni, Cr, As and Pb in roots and Cd and Zn in all plant parts.

  5. The plant secondary metabolite citral alters water status and prevents seed formation in Arabidopsis thaliana.

    PubMed

    Graña, E; Díaz-Tielas, C; López-González, D; Martínez-Peñalver, A; Reigosa, M J; Sánchez-Moreiras, A M

    2016-05-01

    Based on previous results, which showed that the secondary metabolite citral causes disturbances to plant water status, the present study is focused on demonstrating and detailing these effects on the water-related parameters of Arabidopsis thaliana adult plants, and their impact on plant fitness. Clear evidence of effects on water status and fitness were observed: plants treated with 1200 and 2400 μm citral showed decreased RWC, reduced Ψs , increased Ψw and reduced stomatal opening, even 7 days after the beginning of the experiment. Plant protection signals, such as leaf rolling or increased anthocyanin content, were also detected in these plants. In contrast, 14 days after beginning the treatment, treated plants showed signs of citral-related damage. Moreover, the reproductive success of treated plants was critically compromised, with prematurely withered flowers and no silique or seed development. This effect of citral on fitness of adult plants suggests a promising application of this natural compound in weed management by reducing the weed seed bank in the soil.

  6. Role of transpiration and metabolism in translocation and accumulation of cadmium in tobacco plants (Nicotiana tabacum L.).

    PubMed

    Liu, Haiwei; Wang, Haiyun; Ma, Yibing; Wang, Haohao; Shi, Yi

    2016-02-01

    Tobacco plants grown in pots and in hydroponic culture accumulated cadmium (Cd) particularly: the Cd content of tobacco leaves exceeded 100 mg/kg and the enrichment factor (the ratio of Cd in leaves to that in soil) was more than 4. These high levels of accumulation identify tobacco as a hyperaccumulator of Cd. Two transpiration inhibitors (paraffin or CaCl2) and shade decreased the Cd content of tobacco leaves, and the decrease showed a linear relationship with the leaf transpiration rate. A metabolism inhibitor, namely 2,4-dinitrophenol (DNP), and low temperature (4 °C) also lowered the Cd content of tobacco leaves, but the inhibitory effect of low temperature was greater. In the half number of leaves that were shaded, the Cd content decreased to 26.5% of that in leaves that were not shaded in the same tobacco plants. These results suggests that translocation of Cd from the medium to the leaves is driven by the symplastic and the apoplastic pathways. Probably, of the two crucial steps in the translocation of Cd in tobacco plants, one, namely uptake from the medium to the xylem, is energy-dependent whereas the other, namely the transfer from the xylem to the leaves, is driven mainly by transpiration.

  7. Induced expression of AtLEC1 and AtLEC2 differentially promotes somatic embryogenesis in transgenic tobacco plants.

    PubMed

    Guo, Fengdan; Liu, Chuanliang; Xia, Han; Bi, Yuping; Zhao, Chuanzhi; Zhao, Shuzhen; Hou, Lei; Li, Fuguang; Wang, Xingjun

    2013-01-01

    Arabidopsis LEAFY COTYLEDON (LEC) genes, AtLEC1 and AtLEC2, are important embryonic regulators that play key roles in morphogenesis and maturation phases during embryo development. Ectopic expression of AtLEC1 and AtLEC2 in tobacco caused abnormality in transgenic seedling. When transgenic seeds germinated on medium containing 30 µM DEX, LEC1 transgenic seedlings were ivory and fleshy, with unexpanded cotyledons, stubby hypocotyls, short roots and no obvious callus formation at the shoot meristem position. While LEC2 transgenic seedlings formed embryonic callus on the shoot apical meristem and somatic embryo-like structures emerged from the surface of the callus. When callus were transferred to hormone free MS0 medium more shoots were regenerated from each callus. However, shoot formation was not observed in LEC1 overexpressors. To investigate the mechanisms of LEC2 in somatic embryogenesis, we studied global gene expression by digital gene expression profiling analysis. The results indicated that ectopic expression of LEC2 genes induced accumulation of embryo-specific proteins such as seed storage proteins, late embryogenesis abundant (LEA) proteins, fatty acid biosynthetic enzymes, products of steroid biosynthesis related genes and key regulatory genes of the embryo development. Genes of plant-specific transcription factors such as NAC domain protein, AP2 and GRAS family, resistance-related as well as salicylic acid signaling related genes were up-regulated in LEC2 transgenic seedlings. Ectopi c expression of LEC2 induced large number of somatic embryo formation and shoot regeneration but 20 d DEX induction of LEC1 is not sufficient to induce somatic embryogenesis and shoot formation. Our data provide new information to understand the mechanisms on LEC2 gene's induction of somatic embryogenesis.

  8. Expression and Chloroplast Targeting of Cholesterol Oxidase in Transgenic Tobacco Plants

    PubMed Central

    Corbin, David R.; Grebenok, Robert J.; Ohnmeiss, Thomas E.; Greenplate, John T.; Purcell, John P.

    2001-01-01

    Cholesterol oxidase represents a novel type of insecticidal protein with potent activity against the cotton boll weevil (Anthonomus grandis grandis Boheman). We transformed tobacco (Nicotiana tabacum) plants with the cholesterol oxidase choM gene and expressed cytosolic and chloroplast-targeted versions of the ChoM protein. Transgenic leaf tissues expressing cholesterol oxidase exerted insecticidal activity against boll weevil larvae. Our results indicate that cholesterol oxidase can metabolize phytosterols in vivo when produced cytosolically or when targeted to chloroplasts. The transgenic plants exhibiting cytosolic expression accumulated low levels of saturated sterols known as stanols, and displayed severe developmental aberrations. In contrast, the transgenic plants expressing chloroplast-targeted cholesterol oxidase maintained a greater accumulation of stanols, and appeared phenotypically and developmentally normal. These results are discussed within the context of plant sterol distribution and metabolism. PMID:11457962

  9. Abscisic acid and transpiration rate are involved in the response to boron toxicity in Arabidopsis plants.

    PubMed

    Macho-Rivero, Miguel Ángel; Camacho-Cristóbal, Juan José; Herrera-Rodríguez, María Begoña; Müller, Maren; Munné-Bosch, Sergi; González-Fontes, Agustín

    2017-05-01

    Boron (B) is an essential microelement for vascular plant development, but its toxicity is a major problem affecting crop yields in arid and semi-arid areas of the world. In the literature, several genes involved in abscisic acid (ABA) signalling and responses are upregulated in Arabidopsis roots after treatment with excess B. It is known that the AtNCED3 gene, which encodes a crucial enzyme for ABA biosynthesis, plays a key role in the plant response to drought stress. In this study, root AtNCED3 expression and shoot ABA content were rapidly increased in wild-type plants upon B-toxicity treatment. The Arabidopsis ABA-deficient nced3-2 mutant had higher transpiration rate, stomatal conductance and accumulated more B in their shoots than wild-type plants, facts that were associated with the lower levels of ABA in this mutant. However, in wild-type plants, B toxicity caused a significant reduction in stomatal conductance, resulting in a decreased transpiration rate. This response could be a mechanism to limit the transport of excess B from the roots to the leaves under B toxicity. In agreement with the higher transpiration rate of the nced3-2 mutant, this genotype showed an increased leaf B concentration and damage upon exposure to 5 mM B. Under B toxicity, ABA application decreased B accumulation in wild-type and nced3-2 plants. In summary, this work shows that excess B applied to the roots leads to rapid changes in AtNCED3 expression and gas exchange parameters that would contribute to restrain the B entry into the leaves, this effect being mediated by ABA. © 2016 Scandinavian Plant Physiology Society.

  10. Expression of the synthetic neutralizing epitope gene of porcine epidemic diarrhea virus in tobacco plants without nicotine.

    PubMed

    Kang, Tae-Jin; Kim, Young-Sook; Jang, Yong-Suk; Yang, Moon-Sik

    2005-03-18

    Porcine epidemic diarrhea virus (PEDV) causes acute diarrhea and dehydration in pigs, leading to death with a high mortality. In this study, the synthetic neutralizing epitope gene of PEDV, which was optimized based on the coding sequence of tobacco plant genes being modified, was expressed in the no-nicotine tobacco plants. The synthetic gene was cloned into the plant expression vector under the control of CaMV 35S promoter and transformed by an Agrobacterium-mediated transformation. The amount of synthetic epitope protein of PEDV detected in the transgenic tobacco plants was approximately 2.1% of the total soluble plant protein, which was approximately five-fold higher than that expressed with the native gene.

  11. Novel plant immune-priming compounds identified via high-throughput chemical screening target salicylic acid glucosyltransferases in Arabidopsis.

    PubMed

    Noutoshi, Yoshiteru; Okazaki, Masateru; Kida, Tatsuya; Nishina, Yuta; Morishita, Yoshihiko; Ogawa, Takumi; Suzuki, Hideyuki; Shibata, Daisuke; Jikumaru, Yusuke; Hanada, Atsushi; Kamiya, Yuji; Shirasu, Ken

    2012-09-01

    Plant activators are compounds, such as analogs of the defense hormone salicylic acid (SA), that protect plants from pathogens by activating the plant immune system. Although some plant activators have been widely used in agriculture, the molecular mechanisms of immune induction are largely unknown. Using a newly established high-throughput screening procedure that screens for compounds that specifically potentiate pathogen-activated cell death in Arabidopsis thaliana cultured suspension cells, we identified five compounds that prime the immune response. These compounds enhanced disease resistance against pathogenic Pseudomonas bacteria in Arabidopsis plants. Pretreatments increased the accumulation of endogenous SA, but reduced its metabolite, SA-O-β-d-glucoside. Inducing compounds inhibited two SA glucosyltransferases (SAGTs) in vitro. Double knockout plants that lack both SAGTs consistently exhibited enhanced disease resistance. Our results demonstrate that manipulation of the active free SA pool via SA-inactivating enzymes can be a useful strategy for fortifying plant disease resistance and may identify useful crop protectants.

  12. Constitutive heterologous overexpression of a TIR-NB-ARC-LRR gene encoding a putative disease resistance protein from wild Chinese Vitis pseudoreticulata in Arabidopsis and tobacco enhances resistance to phytopathogenic fungi and bacteria.

    PubMed

    Wen, Zhifeng; Yao, Liping; Singer, Stacy D; Muhammad, Hanif; Li, Zhi; Wang, Xiping

    2017-03-01

    Plants use resistance (R) proteins to detect pathogen effector proteins and activate their innate immune response against the pathogen. The majority of these proteins contain an NB-ARC (nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4) domain along with a leucine-rich repeat (LRR), and some also bear a toll interleukin 1 receptor (TIR) domain. In this study, we characterized a gene encoding a TIR-NB-ARC-LRR R protein (VpTNL1) (GenBank accession number KX649890) from wild Chinese grapevine Vitis pseudoreticulata accession "Baihe-35-1", which was identified previously from a transcriptomic analysis of leaves inoculated with powdery mildew (PM; Erysiphe necator (Schw.)). The VpTNL1 transcript was found to be highly induced in V. pseudoreticulata following inoculation with E. necator, as well as treatment with salicylic acid (SA). Sequence analysis demonstrated that the deduced amino acid sequence contained a TIR domain at the N-terminus, along with an NB-ARC and four LRRs domains within the C-terminus. Constitutive expression of VpTNL1 in Arabidopsis thaliana resulted in either a wild-type or dwarf phenotype. Intriguingly, the phenotypically normal transgenic lines displayed enhanced resistance to Arabidopsis PM, Golovinomyces cichoracearum, as well as to the virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000. Similarly, constitutive expression of VpTNL1 in Nicotiana tabacum was found to confer enhanced resistance to tobacco PM, Erysiphe cichoacearum DC. Subsequent isolation of the VpTNL1 promoter and deletion analysis indicated that TC-rich repeats and TCA elements likely play an important role in its response to E. necator and SA treatment, respectively. Taken together, these results indicate that VpTNL1 contributes to PM resistance in grapevine and provide an interesting gene target for the future amelioration of grape via breeding and/or biotechnology.

  13. Decreased SBPase activity alters growth and development in transgenic tobacco plants.

    PubMed

    Lawson, T; Bryant, B; Lefebvre, S; Lloyd, J C; Raines, C A

    2006-01-01

    The effects of reduced SBPase activity on growth and development were examined in a set of transgenic tobacco plants produced using an antisense construct driven by the ribulose bisphosphate carboxylase, small subunit promoter. Photosynthetic carbon assimilation rates and carbohydrate levels in source leaves were decreased in the antisense plants. Growth rate and total shoot biomass were reduced in the SBPase antisense plants, even in plants where SBPase activity was reduced by only 25%. Floral biomass also decreased in response to reductions in SBPase activity and the onset of flowering was delayed by 5-10 d. This is the first demonstration of a link between reproductive biomass and reductions in Calvin cycle enzyme activity using antisense plants. Furthermore, unexpected changes in the growth and development of the antisense plants were evident. Small reductions in SBPase activity (above 50% wild type) resulted in shorter plants with only a small decrease in stem biomass and specific leaf area. In contrast, plants with larger reductions in SBPase activity had an increase in specific leaf area and attained heights similar to that of the wild-type plants but with a much reduced stem biomass, largely due to a decrease in xylem tissue. This bi-modal response of growth to reductions in SBPase activity has similarities to changes in leaf and stem anatomy and morphology that accompany light acclimation.

  14. Identification, duplication, evolution and expression analyses of caleosins in Brassica plants and Arabidopsis subspecies.

    PubMed

    Shen, Yue; Liu, Mingzhe; Wang, Lili; Li, Zhuowei; Taylor, David C; Li, Zhixi; Zhang, Meng

    2016-04-01

    Caleosins are a class of Ca(2+) binding proteins that appear to be ubiquitous in plants. Some of the main proteins embedded in the lipid monolayer of lipid droplets, caleosins, play critical roles in the degradation of storage lipids during germination and in lipid trafficking. Some of them have been shown to have histidine-dependent peroxygenase activity, which is believed to participate in stress responses in Arabidopsis. In the model plant Arabidopsis thaliana, caleosins have been examined extensively. However, little is known on a genome-wide scale about these proteins in other members of the Brassicaceae. In this study, 51 caleosins in Brassica plants and Arabidopsis lyrata were investigated and analyzed in silico. Among them, 31 caleosins, including 7 in A. lyrata, 11 in Brassica oleracea and 13 in Brassica napus, are herein identified for the first time. Segmental duplication was the main form of gene expansion. Alignment, motif and phylogenetic analyses showed that Brassica caleosins belong to either the H-family or the L-family with different motif structures and physicochemical properties. Our findings strongly suggest that L-caleosins are evolved from H-caleosins. Predicted phosphorylation sites were differentially conserved in H-caleosin and L-caleosins, respectively. 'RY-repeat' elements and phytohormone-related cis-elements were identified in different caleosins, which suggest diverse physiological functions. Gene structure analysis indicated that most caleosins (38 out of 44) contained six exons and five introns and their intron phases were highly conserved. Structurally integrated caleosins, such as BrCLO3-3 and BrCLO4-2, showed high expression levels and may have important roles. Some caleosins, such as BrCLO2 and BoCLO8-2, lost motifs of the calcium binding domain, proline knot, potential phosphorylation sites and haem-binding sites. Combined with their low expression, it is suggested that these caleosins may have lost function.

  15. Mitochondrial malate dehydrogenase lowers leaf respiration and alters photorespiration and plant growth in Arabidopsis.

    PubMed

    Tomaz, Tiago; Bagard, Matthieu; Pracharoenwattana, Itsara; Lindén, Pernilla; Lee, Chun Pong; Carroll, Adam J; Ströher, Elke; Smith, Steven M; Gardeström, Per; Millar, A Harvey

    2010-11-01

    Malate dehydrogenase (MDH) catalyzes a reversible NAD(+)-dependent-dehydrogenase reaction involved in central metabolism and redox homeostasis between organelle compartments. To explore the role of mitochondrial MDH (mMDH) in Arabidopsis (Arabidopsis thaliana), knockout single and double mutants for the highly expressed mMDH1 and lower expressed mMDH2 isoforms were constructed and analyzed. A mmdh1mmdh2 mutant has no detectable mMDH activity but is viable, albeit small and slow growing. Quantitative proteome analysis of mitochondria shows changes in other mitochondrial NAD-linked dehydrogenases, indicating a reorganization of such enzymes in the mitochondrial matrix. The slow-growing mmdh1mmdh2 mutant has elevated leaf respiration rate in the dark and light, without loss of photosynthetic capacity, suggesting that mMDH normally uses NADH to reduce oxaloacetate to malate, which is then exported to the cytosol, rather than to drive mitochondrial respiration. Increased respiratory rate in leaves can account in part for the low net CO(2) assimilation and slow growth rate of mmdh1mmdh2. Loss of mMDH also affects photorespiration, as evidenced by a lower postillumination burst, alterations in CO(2) assimilation/intercellular CO(2) curves at low CO(2), and the light-dependent elevated concentration of photorespiratory metabolites. Complementation of mmdh1mmdh2 with an mMDH cDNA recovered mMDH activity, suppressed respiratory rate, ameliorated changes to photorespiration, and increased plant growth. A previously established inverse correlation between mMDH and ascorbate content in tomato (Solanum lycopersicum) has been consolidated in Arabidopsis and may potentially be linked to decreased galactonolactone dehydrogenase content in mitochondria in the mutant. Overall, a central yet complex role for mMDH emerges in the partitioning of carbon and energy in leaves, providing new directions for bioengineering of plant growth rate and a new insight into the molecular mechanisms

  16. Antimicrobial activity of {gamma}-thionin-like soybean SE60 in E. coli and tobacco plants

    SciTech Connect

    Choi, Yeonhee Choi, Yang Do; Lee, Jong Seob

    2008-10-17

    The SE60, a low molecular weight, sulfur-rich protein in soybean, is known to be homologous to wheat {gamma}-purothionin. To elucidate the functional role of SE60, we expressed SE60 cDNA in Escherichia coli and in tobacco plants. A single protein band was detected by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) after anti-FLAG affinity purification of the protein from transformed E. coli. While the control E. coli cells harboring pFLAG-1 showed standard growth with Isopropyl {beta}-D-1-thiogalactopyranoside (IPTG) induction, E. coli cells expressing the SE60 fusion protein did not grow at all, suggesting that SE60 has toxic effects on E. coli growth. Genomic integration and the expression of transgene in the transgenic tobacco plants were confirmed by Southern and Northern blot analysis, respectively. The transgenic plants demonstrated enhanced resistance against the pathogen Pseudomonas syringae. Taken together, these results strongly suggest that SE60 has antimicrobial activity and play a role in the defense mechanism in soybean plants.

  17. Dynamic imaging of glucose flux impedance using FRET sensors in wild-type Arabidopsis plants.

    PubMed

    Chaudhuri, Bhavna; Hörmann, Friederike; Frommer, Wolf B

    2011-04-01

    Quantitative and dynamic analysis of metabolites and signalling molecules is limited by technical challenges in obtaining temporally resolved information at the cellular and compartmental level. Real-time information on signalling and metabolite levels with subcellular granularity can be obtained with the help of genetically encoded FRET (Förster resonance energy transfer) nanosensors. FRET nanosensors represent powerful tools for gene discovery, and analysis of regulatory networks, for example by screening mutants. However, RNA silencing has impaired our ability to express FRET nanosensors functionally in Arabidopsis plants. This drawback was overcome here by expressing the nanosensors in RNA silencing mutants. However, the use of silencing mutants requires the generation of homozygous lines deficient in RNA silencing as well as the mutation of interest and co-expression of the nanosensor. Here it is shown that dynamic changes in cytosolic glucose levels can readily be quantified in wild-type Arabidopsis plants at early stages of development (7-15 d) before silencing had a major effect on fluorescence intensity. A detailed protocol for screening 10-20 mutant seedlings per day is provided. The detailed imaging protocol provided here is suitable for analysing sugar flux in young wild-type plants as well as mutants affected in sugar signalling, metabolism, or transport using a wide spectrum of FRET nanosensors.

  18. DNA repair and recombination in higher plants: insights from comparative genomics of arabidopsis and rice

    PubMed Central

    2010-01-01

    Background The DNA repair and recombination (DRR) proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. Results We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. Conclusions The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms. PMID:20646326

  19. The Arabidopsis KIN17 and its homolog KLP mediate different aspects of plant growth and development.

    PubMed

    Garcia-Molina, Antoni; Xing, Shuping; Huijser, Peter

    2014-01-01

    Proteins harboring the kin17 domain (KIN17) constitute a family of well-conserved eukaryotic nuclear proteins involved in nucleic acid metabolism. In mammals, KIN17 orthologs contribute to DNA replication, RNA splicing, and DNA integrity maintenance. Recently, we reported a functional characterization of an Arabidopsis thaliana KIN17 homolog (AtKIN17) that uncovered a role for this protein in tuning physiological responses during copper (Cu) deficiency and oxidative stress. However, functions similar to those described in mammals may also be expected in plants given the conservation of functional domains in KIN17 orthologs. Here, we provide additional data consistent with the participation of AtKIN17 in controlling general plant growth and development, as well as in response to UV radiation. Furthermore, the Arabidopsis genome codes for a second homolog to KIN17, we referred to as KIN17-like-protein (KLP). KLP loss-of-function lines exhibited a reduced inhibition of root growth in response to copper excess and relatively elongated hypocotyls in etiolated seedlings. Altogether, our experimental data point to a general function of the kin17 domain proteins in plant growth and development.

  20. The Arabidopsis KIN17 and its homolog KLP mediate different aspects of plant growth and development

    PubMed Central

    Garcia-Molina, Antoni; Xing, Shuping; Huijser, Peter

    2014-01-01

    Proteins harboring the kin17 domain (KIN17) constitute a family of well-conserved eukaryotic nuclear proteins involved in nucleic acid metabolism. In mammals, KIN17 orthologs contribute to DNA replication, RNA splicing, and DNA integrity maintenance. Recently, we reported a functional characterization of an Arabidopsis thaliana KIN17 homolog (AtKIN17) that uncovered a role for this protein in tuning physiological responses during copper (Cu) deficiency and oxidative stress. However, functions similar to those described in mammals may also be expected in plants given the conservation of functional domains in KIN17 orthologs. Here, we provide additional data consistent with the participation of AtKIN17 in controlling general plant growth and development, as well as in response to UV radiation. Furthermore, the Arabidopsis genome codes for a second homolog to KIN17, we referred to as KIN17-LIKE-PROTEIN (KLP). KLP loss-of-function lines exhibited a reduced inhibition of root growth in response to copper excess and relatively elongated hypocotyls in etiolated seedlings. Altogether, our experimental data point to a general function of the kin17 domain proteins in plant growth and development. PMID:24713636

  1. In Arabidopsis thaliana, 1% of the genome codes for a novel protein family unique to plants.

    PubMed

    Aubourg, S; Boudet, N; Kreis, M; Lecharny, A

    2000-03-01

    In the sequences released by the Arabidopsis Genome Initiative (AGI), we discovered a new and unexpectedly large family of orphan genes (127 genes by 01.08.99), named AtPCMP. The distribution of the AtPCMP genes on the five chromosomes suggests that the genome of Arabidopsis thaliana contains more than 200 genes of this family (1% of the whole genome). The deduced AtPCMP proteins are characterized by a surprising combinatorial organization of sequence motifs. The amino-terminal domain is made of a succession of three conserved motifs which generate an important diversity. These proteins are classified into three subfamilies based on the length and nature of their carboxy-terminal domain constituted by 1-6 motifs. All the motifs characterized have an important level of conservation in both sequence and spacing. A specific signature of this large family is defined. The presence of ESTs in databases and the detection of clones in A. thaliana cDNA libraries indicate that most of the genes of this family are expressed. The absence of similar sequences outside the plant kingdom strongly suggests that this unusually large orphan family is unique to plants. Features, the genesis, the potential function and the evolution of this plant combinatorial and modular protein family are discussed.

  2. IRT1, an Arabidopsis transporter essential for iron uptake from the soil and for plant growth.

    PubMed

    Vert, Grégory; Grotz, Natasha; Dédaldéchamp, Fabienne; Gaymard, Frédéric; Guerinot, Mary Lou; Briat, Jean-François; Curie, Catherine

    2002-06-01

    Plants are the principal source of iron in most diets, yet iron availability often limits plant growth. In response to iron deficiency, Arabidopsis roots induce the expression of the divalent cation transporter IRT1. Here, we present genetic evidence that IRT1 is essential for the uptake of iron from the soil. An Arabidopsis knockout mutant in IRT1 is chlorotic and has a severe growth defect in soil, leading to death. This defect is rescued by the exogenous application of iron. The mutant plants do not take up iron and fail to accumulate other divalent cations in low-iron conditions. IRT1-green fluorescent protein fusion, transiently expressed in culture cells, localized to the plasma membrane. We also show, through promoter::beta-glucuronidase analysis and in situ hybridization, that IRT1 is expressed in the external cell layers of the root, specifically in response to iron starvation. These results clearly demonstrate that IRT1 is the major transporter responsible for high-affinity metal uptake under iron deficiency.

  3. Modified cellulose synthase gene from 'Arabidopsis thaliana' confers herbicide resistance to plants

    SciTech Connect

    Somerville, Chris R.; Scieble, Wolf

    2000-10-11

    Cellulose synthase ('CS'), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl) phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  4. Modified cellulose synthase gene from Arabidopsis thaliana confers herbicide resistance to plants

    SciTech Connect

    Somerville, Chris R.; Scheible, Wolf

    2007-07-10

    Cellulose synthase ("CS"), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl)phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  5. Seed coat mucilage cells of Arabidopsis thaliana as a model for plant cell wall research.

    PubMed

    Arsovski, Andrej A; Haughn, George W; Western, Tamara L

    2010-07-01

    Plant cells are encased within a complex polysaccharide wall that strengthens the cell and has key roles in all aspects of plant cell growth, differentiation, and interaction with the environment. This dynamic structure is under continual modification during plant development, and its synthesis and modification require the activity of a myriad of enzymes. The mucilage secretory cells (MSCs) of the Arabidopsis thaliana seed coat provide a model for the discovery of novel genes involved in the synthesis, secretion and modification of cell wall components, particularly pectin. These cells synthesize copious amounts of pectinaceous mucilage during development and, upon hydration of the desiccated seed, the mucilage rapidly swells, bursts from the MSCs and surrounds the seed in a gelatinous capsule. Several genes affecting MSC differentiation, pectin synthesis, and mucilage release have been identified and additional genes involved in these and related processes including pectin secretion and the mechanical alteration of cell walls await to be discovered.

  6. "Out of pollen" hypothesis for origin of new genes in flowering plants: study from Arabidopsis thaliana.

    PubMed

    Wu, Dong-Dong; Wang, Xin; Li, Yan; Zeng, Lin; Irwin, David M; Zhang, Ya-Ping

    2014-09-17

    New genes, which provide material for evolutionary innovation, have been extensively studied for many years in animals where it is observed that they commonly show an expression bias for the testis. Thus, the testis is a major source for the generation of new genes in animals. The source tissue for new genes in plants is unclear. Here, we find that new genes in plants show a bias in expression to mature pollen, and are also enriched in a gene coexpression module that correlates with mature pollen in Arabidopsis thaliana. Transposable elements are significantly enriched in the new genes, and the high activity of transposable elements in the vegetative nucleus, compared with the germ cells, suggests that new genes are most easily generated in the vegetative nucleus in the mature pollen. We propose an "out of pollen" hypothesis for the origin of new genes in flowering plants.

  7. The Arabidopsis TOR kinase links plant growth, yield, stress resistance and mRNA translation.

    PubMed

    Deprost, Dorothée; Yao, Lei; Sormani, Rodnay; Moreau, Manon; Leterreux, Guillaume; Nicolaï, Maryse; Bedu, Magali; Robaglia, Christophe; Meyer, Christian

    2007-09-01

    Plants, unlike animals, have plastic organ growth that is largely dependent on environmental information. However, so far, little is known about how this information is perceived and transduced into coherent growth and developmental decisions. Here, we report that the growth of Arabidopsis is positively correlated with the level of expression of the TARGET OF RAPAMYCIN (TOR) kinase. Diminished or augmented expression of the AtTOR gene results in a dose-dependent decrease or increase, respectively, in organ and cell size, seed production and resistance to osmotic stress. Strong downregulation of AtTOR expression by inducible RNA interference also leads to a post-germinative halt in growth and development, which phenocopies the action of the plant hormone abscisic acid, to an early senescence and to a reduction in the amount of translated messenger RNA. Thus, we propose that the AtTOR kinase is one of the contributors to the link between environmental cues and growth processes in plants.

  8. A gene stacking approach leads to engineered plants with highly increased galactan levels in Arabidopsis

    DOE PAGES

    Gondolf, Vibe M.; Stoppel, Rhea; Ebert, Berit; ...

    2014-12-10

    Background: Engineering of plants with a composition of lignocellulosic biomass that is more suitable for downstream processing is of high interest for next-generation biofuel production. Lignocellulosic biomass contains a high proportion of pentose residues, which are more difficult to convert into fuels than hexoses. Therefore, increasing the hexose/pentose ratio in biomass is one approach for biomass improvement. A genetic engineering approach was used to investigate whether the amount of pectic galactan can be specifically increased in cell walls of Arabidopsis fiber cells, which in turn could provide a potential source of readily fermentable galactose. Results: First it was tested ifmore » overexpression of various plant UDP-glucose 4-epimerases (UGEs) could increase the availability of UDP-galactose and thereby increase the biosynthesis of galactan. Constitutive and tissue-specific expression of a poplar UGE and three Arabidopsis UGEs in Arabidopsis plants could not significantly increase the amount of cell wall bound galactose. We then investigated co-overexpression of AtUGE2 together with the β-1,4-galactan synthase GalS1. Co-overexpression of AtUGE2 and GalS1 led to over 80% increase in cell wall galactose levels in Arabidopsis stems, providing evidence that these proteins work synergistically. Furthermore, AtUGE2 and GalS1 overexpression in combination with overexpression of the NST1 master regulator for secondary cell wall biosynthesis resulted in increased thickness of fiber cell walls in addition to the high cell wall galactose levels. Immunofluorescence microscopy confirmed that the increased galactose was present as β-1,4-galactan in secondary cell walls. Conclusions: This approach clearly indicates that simultaneous overexpression of AtUGE2 and GalS1 increases the cell wall galactose to much higher levels than can be achieved by overexpressing either one of these proteins alone. Moreover, the increased galactan content in fiber cells while

  9. Plant responses to environmental stress: regulation and functions of the Arabidopsis TCH genes

    NASA Technical Reports Server (NTRS)

    Braam, J.; Sistrunk, M. L.; Polisensky, D. H.; Xu, W.; Purugganan, M. M.; Antosiewicz, D. M.; Campbell, P.; Johnson, K. A.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    Expression of the Arabidopsis TCH genes is markedly upregulated in response to a variety of environmental stimuli including the seemingly innocuous stimulus of touch. Understanding the mechanism(s) and factors that control TCH gene regulation will shed light on the signaling pathways that enable plants to respond to environmental conditions. The TCH proteins include calmodulin, calmodulin-related proteins and a xyloglucan endotransglycosylase. Expression analyses and localization of protein accumulation indicates that the potential sites of TCH protein function include expanding cells and tissues under mechanical strain. We hypothesize that at least a subset of the TCH proteins may collaborate in cell wall biogenesis.

  10. Plant responses to environmental stress: regulation and functions of the Arabidopsis TCH genes

    NASA Technical Reports Server (NTRS)

    Braam, J.; Sistrunk, M. L.; Polisensky, D. H.; Xu, W.; Purugganan, M. M.; Antosiewicz, D. M.; Campbell, P.; Johnson, K. A.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    Expression of the Arabidopsis TCH genes is markedly upregulated in response to a variety of environmental stimuli including the seemingly innocuous stimulus of touch. Understanding the mechanism(s) and factors that control TCH gene regulation will shed light on the signaling pathways that enable plants to respond to environmental conditions. The TCH proteins include calmodulin, calmodulin-related proteins and a xyloglucan endotransglycosylase. Expression analyses and localization of protein accumulation indicates that the potential sites of TCH protein function include expanding cells and tissues under mechanical strain. We hypothesize that at least a subset of the TCH proteins may collaborate in cell wall biogenesis.

  11. A gene stacking approach leads to engineered plants with highly increased galactan levels in Arabidopsis

    SciTech Connect

    Gondolf, Vibe M.; Stoppel, Rhea; Ebert, Berit; Rautengarten, Carsten; Liwanag, April J.M.; Loqué, Dominique; Scheller, Henrik V.

    2014-12-10

    Background: Engineering of plants with a composition of lignocellulosic biomass that is more suitable for downstream processing is of high interest for next-generation biofuel production. Lignocellulosic biomass contains a high proportion of pentose residues, which are more difficult to convert into fuels than hexoses. Therefore, increasing the hexose/pentose ratio in biomass is one approach for biomass improvement. A genetic engineering approach was used to investigate whether the amount of pectic galactan can be specifically increased in cell walls of Arabidopsis fiber cells, which in turn could provide a potential source of readily fermentable galactose. Results: First it was tested if overexpression of various plant UDP-glucose 4-epimerases (UGEs) could increase the availability of UDP-galactose and thereby increase the biosynthesis of galactan. Constitutive and tissue-specific expression of a poplar UGE and three Arabidopsis UGEs in Arabidopsis plants could not significantly increase the amount of cell wall bound galactose. We then investigated co-overexpression of AtUGE2 together with the β-1,4-galactan synthase GalS1. Co-overexpression of AtUGE2 and GalS1 led to over 80% increase in cell wall galactose levels in Arabidopsis stems, providing evidence that these proteins work synergistically. Furthermore, AtUGE2 and GalS1 overexpression in combination with overexpression of the NST1 master regulator for secondary cell wall biosynthesis resulted in increased thickness of fiber cell walls in addition to the high cell wall galactose levels. Immunofluorescence microscopy confirmed that the increased galactose was present as β-1,4-galactan in secondary cell walls. Conclusions: This approach clearly indicates that simultaneous overexpression of AtUGE2 and GalS1 increases the cell wall galactose to much higher levels than can be achieved by overexpressing either one of these proteins alone. Moreover, the increased galactan content in

  12. [Salt Stress Response in Arabidopsis thaliana Plants with Defective Jasmonate Signaling].

    PubMed

    Yastreb, T O; Kolupayev, Yu E; Shvidenko, A A; Lugovaya, A A; Dmitriev, A P

    2015-01-01

    The effects of exogenous jasmonic acid (JA) on antioxidant enzymes in four-week-old leaves of wild-type Arabidopsis thaliana L. (Columbia-0) and jin1 (jasmonate insensitive 1) mutant plants with defective jasmonate signaling were investigated under normal conditions and under salt stress (200 mM NaCl, 24 h). The wild-type plants responded to JA by an increase in the activities of Cu/Zn superoxide dismutase, catalase, and guaiacol peroxidase, while there was no change in the case of the mutant plants. In response to the salt stress of both the wild-type and mutant genotypes, the activities of superoxide dismutase, catalase, and guaiacol peroxidase were unchanged, decreased, and increased, respectively. The JA-treated wild type plants showed the highest activity of all three enzymes as compared with the mutant plants. Salinity caused a decrease in chlorophyll content in the wild-type and jin 1 plants. Preliminary JA treatment of the Col-0 plants resulted in a normal content of photosynthetic pigments after the salt stress, while the positive JA effect was insignificant in the jin 1 mutants. It was concluded that the MYC2/JIN 1 protein is involved in the JA signal transduction and plant adaptation to salt stress.

  13. Transcriptome analysis of Arabidopsis thaliana plants in response to kin and stranger recognition

    PubMed Central

    Biedrzycki, Meredith L; Venkatachalam, L

    2011-01-01

    Recent reports have demonstrated that Arabidopsis thaliana has the ability to alter its growth differentially when grown in the presence of secretions from other A. thaliana plants that are kin or strangers; however, little knowledge has been gained as to the physiological processes involved in these plant-plant interactions. Therefore, we examined the root transcriptome of A. thaliana plants exposed to stranger vs. kin secretions to determine genes involved in these processes. We conducted a whole transcriptome analysis on root tissues and categorized genes with significant changes in expression. Genes from four categories of interest based on significant changes in expression were identified as ATP/GST transporter, auxin/auxin related, secondary metabolite and pathogen response genes. Multiple genes in each category were tested and results indicated that pathogen response genes were involved in the kin recognition response. Plants were then infected with Pseudomonas syringe pv. Tomato DC3000 to further examine the role of these genes in plants exposed to own, kin and stranger secretions in pathogen resistance. This study concluded that multiple physiological pathways are involved in the kin recognition. The possible implication of this study opens up a new dialog in terms of how plant-plant interactions change under a biotic stress. PMID:21900741

  14. Transcriptome analysis of Arabidopsis thaliana plants in response to kin and stranger recognition.

    PubMed

    Biedrzycki, Meredith L; L, Venkatachalam; Bais, Harsh P

    2011-10-01

    Recent reports have demonstrated that Arabidopsis thaliana has the ability to alter its growth differentially when grown in the presence of secretions from other A. thaliana plants that are kin or strangers, however, little knowledge has been gained as to the physiological processes involved in these plant-plant interactions. Therefore, we examined the root transcriptome of A. thaliana plants exposed to stranger versus kin secretions to determine genes involved in these processes. We conducted a whole transcriptome analysis on root tissues and categorized genes with significant changes in expression. Genes from four categories of interest based on significant changes in expression were identified as ATP/GST transporter, auxin/auxin related, secondary metabolite and pathogen response genes. Multiple genes in each category were tested and results indicated that pathogen response genes were involved in the kin recognition response. Plants were then infected with Pseudomonas syringe pv. Tomato DC3000 to further examine the role of these genes in plants exposed to own, kin and stranger secretions in pathogen resistance. This study concluded that multiple physiological pathways are involved in the kin recognition. The possible implication of this study opens up a new dialogue in terms of how plant-plant interactions change under a biotic stress.

  15. 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

  16. Pathogen-induced systemic activation of a plant defensin gene in Arabidopsis follows a salicylic acid-independent pathway.

    PubMed Central

    Penninckx, I A; Eggermont, K; Terras, F R; Thomma, B P; De Samblanx, G W; Buchala, A; Métraux, J P; Manners, J M; Broekaert, W F

    1996-01-01

    A 5-kD plant defensin was purified from Arabidopsis leaves challenged with the fungus Alternaria brassicicola and shown to possess antifungal properties in vitro. The corresponding plant defensin gene was induced after treatment of leaves with methyl jasmonate or ethylene but not with salicylic acid or 2,6-dichloroisonicotinic acid. When challenged with A. brassicicola, the levels of the plant defensin protein and mRNA rose both in inoculated leaves and in nontreated leaves of inoculated plants (systemic leaves). These events coincided with an increase in the endogenous jasmonic acid content of both types of leaves. Systemic pathogen-induced expression of the plant defensin gene was unaffected in Arabidopsis transformants (nahG) or mutants (npr1 and cpr1) affected in the salicylic acid response but was strongly reduced in the Arabidopsis mutants eln2 and col1 that are blocked in their response to ethylene and methyl jasmonate, respectively. Our results indicate that systemic pathogen-induced expression of the plant defensin gene in Arabidopsis is independent of salicylic acid but requires components of the ethylene and jasmonic acid response. PMID:8989885

  17. Transgene silencing and transgene-derived siRNA production in tobacco plants homozygous for an introduced AtMYB90 construct

    USDA-ARS?s Scientific Manuscript database

    Transgenic tobacco (Nicotiana tabacum) lines were engineered to ectopically over-express AtMYB90 (PAP2), an R2-R3 Myb gene associated with regulation of anthocyanin production in Arabidopsis thaliana. Independently transformed transgenic lines Myb27 and Myb237 accumulated large quantities of anthoc...

  18. [Content of Osmolytes and Flavonoids under Salt Stress in Arabidopsis thaliana Plants Defective in Jasmonate Signaling].

    PubMed

    Yastreb, T O; Kolupaev, Yu E; Lugovaya, A A; Dmitriev, A P

    2016-01-01

    The effects of the salt stress (200 mM NaCl) and exogenous jasmonic acid (JA) on levels of osmolytes and flavonoids in leaves of four-week-old Arabidopsis thaliana L. plants of the wild-type (WT) Columbia-0 (Col-0) and the mutant jin1 (jasmonate insensitive 1) with impaired jasmonate signaling were studied. The increase in proline content caused by the salt stress was higher in the Col-0 plants than in the mutant jin1. This difference was especially marked if the plants had been pretreated with exogenous 0.1 µM JA. The sugar content increased in response to the salt stress in the JA-treated WT plants but decreased in the jin1 mutant. Leaf treatment with JA of the WT plants but not mutant defective in jasmonate signaling also enhanced the levels of anthocyanins and flavonoids absorbed in UV-B range. The presence of JA increased salinity resistance of the Col-0 plants, since the accumulation of lipid peroxidation products and growth inhibition caused by NaCl were less pronounced. Under salt stress, JA almost did not render a positive effect on the jin1 plants. It is concluded that the protein JIN1/MYC2 is involved in control of protective systems under salt stress.

  19. Dynamics of male meiotic recombination frequency during plant development using Fluorescent Tagged Lines in Arabidopsis thaliana

    PubMed Central

    Li, Fan; De Storme, Nico; Geelen, Danny

    2017-01-01

    Meiotic homologous recombination plays a central role in creating genetic variability, making it an essential biological process relevant to evolution and crop breeding. In this study, we used pollen-specific fluorescent tagged lines (FTLs) to measure male meiotic recombination frequency during the development of Arabidopsis thaliana. Interestingly, a subset of pollen grains consistently shows loss of fluorescence expression in tested lines. Using nine independent FTL intervals, the spatio-temporal dynamics of male recombination frequency was assessed during plant development, considering both shoot type and plant age as independent parameters. In most genomic intervals assayed, male meiotic recombination frequency is highly consistent during plant development, showing no significant change between different shoot types and during plant aging. However, in some genomic regions, such as I1a and I5a, a small but significant effect of either developmental position or plant age were observed, indicating that the meiotic CO frequency in those intervals varies during plant development. Furthermore, from an overall view of all nine genomic intervals assayed, both primary and tertiary shoots show a similar dynamics of increasing recombination frequency during development, while secondary and lateral shoots remain highly stable. Our results provide new insights in the dynamics of male meiotic recombination frequency during plant development. PMID:28211906

  20. Dynamics of male meiotic recombination frequency during plant development using Fluorescent Tagged Lines in Arabidopsis thaliana.

    PubMed

    Li, Fan; De Storme, Nico; Geelen, Danny

    2017-02-13

    Meiotic homologous recombination plays a central role in creating genetic variability, making it an essential biological process relevant to evolution and crop breeding. In this study, we used pollen-specific fluorescent tagged lines (FTLs) to measure male meiotic recombination frequency during the development of Arabidopsis thaliana. Interestingly, a subset of pollen grains consistently shows loss of fluorescence expression in tested lines. Using nine independent FTL intervals, the spatio-temporal dynamics of male recombination frequency was assessed during plant development, considering both shoot type and plant age as independent parameters. In most genomic intervals assayed, male meiotic recombination frequency is highly consistent during plant development, showing no significant change between different shoot types and during plant aging. However, in some genomic regions, such as I1a and I5a, a small but significant effect of either developmental position or plant age were observed, indicating that the meiotic CO frequency in those intervals varies during plant development. Furthermore, from an overall view of all nine genomic intervals assayed, both primary and tertiary shoots show a similar dynamics of increasing recombination frequency during development, while secondary and lateral shoots remain highly stable. Our results provide new insights in the dynamics of male meiotic recombination frequency during plant development.

  1. Genetic engineering of the biosynthesis of glycinebetaine enhances thermotolerance of photosystem II in tobacco plants.

    PubMed

    Yang, Xinghong; Wen, Xiaogang; Gong, Hongmei; Lu, Qingtao; Yang, Zhipan; Tang, Yunlai; Liang, Zheng; Lu, Congming

    2007-02-01

    Genetically engineered tobacco (Nicotiana tabacum L.) with the ability to accumulate glycinebetaine was established. The wild type and transgenic plants were exposed to heat treatment (25-50 degrees C) for 4 h in the dark and under growth light intensity (300 mumol m(-2) s(-1)). The analyses of oxygen-evolving activity and chlorophyll fluorescence demonstrated that photosystem II (PSII) in transgenic plants showed higher thermotolerance than in wild type plants in particular when heat stress was performed in the light, suggesting that the accumulation of glycinebetaine leads to increased tolerance to heat-enhanced photoinhibition. This increased tolerance was associated with an improvement on thermostability of the oxygen-evolving complex and the reaction center of PSII. The enhanced tolerance was caused by acceleration of the repair of PSII from heat-enhanced photoinhibition. Under heat stress, there was a significant accumulation of H(2)O(2), O (2) (-) and catalytic Fe in wild type plants but this accumulation was much less in transgenic plants. Heat stress significantly decreased the activities of catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase in wild type plants whereas the activities of these enzymes either decreased much less or maintained or even increased in transgenic plants. In addition, heat stress increased the activity of superoxide dismutase in wild type plants but this increase was much greater in transgenic plants. Furthermore, transgenic plants also showed higher content of ascorbate and reduced glutathione than that of wild type plants under heat stress. The results suggest that the increased thermotolerance induced by accumulation of glycinebetaine in vivo was associated with the enhancement of the repair of PSII from heat-enhanced photo inhibition, which might be due to less accumulation of reactive oxygen species in transgenic plants.

  2. Extremely low frequency weak magnetic fields enhance resistance of NN tobacco plants to tobacco mosaic virus and elicit stress-related biochemical activities.

    PubMed

    Trebbi, Grazia; Borghini, Francesco; Lazzarato, Lisa; Torrigiani, Patrizia; Calzoni, G Lorenzo; Betti, Lucietta

    2007-04-01

    Increasing evidence has accumulated concerning the biological effects of extremely low frequency magnetic fields (ELF-MFs) in different plant models. In the present study, effects of ELF-MFs in tobacco plants reacting to tobacco mosaic virus (TMV) with a hypersensitive response (HR) were evaluated. Plants were exposed for 8 or 24 h (either before or after TMV inoculation) to a static MF, at either -17 or 13 microT, combined with a 10 Hz sinusoidal MF with different intensities (25.6 or 28.9 microT). The working variables were the area and number of hypersensitive lesions in leaves. Following ELF-MFs exposure, an increased resistance was detected, particularly after an 8-h treatment, as shown by the decrease in lesion area and number. Moreover, two enzyme activities involved in resistance mechanisms were analyzed: ornithine decarboxylase (ODC) and phenylalanine ammonia-lyase (PAL). Uninoculated leaves previously exposed to ELF-MFs in general showed a significant increase relative to controls in ODC and PAL activities, in particular for 13 microT static MF plus 28.9 microT, 10 Hz sinusoidal MF (24 h) treatment. In conclusion, ELF-MFs seem to influence the HR of tobacco to TMV, as shown by the increased resistance and changes in ODC and PAL activities, indicating the reliability of the present plant model in the study of bioelectromagnetic interactions.

  3. Research on Time and Spatial Variability of Soil pH in Sanmenxia Planted Tobacco Area

    NASA Astrophysics Data System (ADS)

    Qiao, Hongbo; Rui, Gao; Hui, Zhang; Chen, Yanchun; Su, Yongshi

    Geostatistics combined with GIS spatial technology was applied to analyze the time and spatial variability of pH in topsoil(0-20cm) for planted tobacco region in Sanmenxia district. The results indicated that the pH value range form 6.5 to 8.8 and meet to the need of produce high quality tobacco, but the pH value of partial region is high. The pH value accord with logarithm normal distribution, variance coefficient is 15.2% and 4.5% of 2002 and 2007 year respectively. The semivariogram of pH was best described by the exponential model and spatial heterogeneity of pH were 55.77km and 92.39km. The Kriging interpolated method was applied to calculated the unobserved points and was used to generate the spatial and discrepancy map, analyzed the reason of the pH value increase and the method to improve soil. The research supply important method of the Sanmenxia high quality tobacco produce.

  4. Microsatellite Instability in Arabidopsis Increases with Plant Development1[W][OA

    PubMed Central

    Golubov, Andrey; Yao, Youli; Maheshwari, Priti; Bilichak, Andriy; Boyko, Alex; Belzile, François; Kovalchuk, Igor

    2010-01-01

    Plant development consists of the initial phase of intensive cell division followed by continuous genome endoreduplication, cell growth, and elongation. The maintenance of genome stability under these conditions is the main task performed by DNA repair and genome surveillance mechanisms. Our previous work showed that the rate of homologous recombination repair in older plants decreases. We hypothesized that this age-dependent decrease in the recombination rate is paralleled with other changes in DNA repair capacity. Here, we analyzed microsatellite stability using transgenic Arabidopsis (Arabidopsis thaliana) plants that carry the nonfunctional β-glucuronidase gene disrupted by microsatellite repeats. We found that microsatellite instability increased dramatically with plant age. We analyzed the contribution of various mechanisms to microsatellite instability, including replication errors and mistakes of DNA repair mechanisms such as mismatch repair, excision repair, and strand break repair. Analysis of total DNA polymerase activity using partially purified protein extracts showed an age-dependent decrease in activity and an increase in fidelity. Analysis of the steady-state RNA level of DNA replicative polymerases α, δ, Pol I-like A, and Pol I-like B and the expression of mutS homolog 2 (Msh2) and Msh6 showed an age-dependent decrease. An in vitro repair assay showed lower efficiency of nonhomologous end joining in older plants, paralleled by an increase in Ku70 gene expression. Thus, we assume that the more frequent involvement of nonhomologous end joining in strand break repair and the less efficient end-joining repair together with lower levels of mismatch repair activities may be the main contributors to the observed age-dependent increase in microsatellite instability. PMID:20817752

  5. NPP1, a Phytophthora-associated trigger of plant defense in parsley and Arabidopsis.

    PubMed

    Fellbrich, Guido; Romanski, Annette; Varet, Anne; Blume, Beatrix; Brunner, Frédéric; Engelhardt, Stefan; Felix, Georg; Kemmerling, Birgit; Krzymowska, Magdalena; Nürnberger, Thorsten

    2002-11-01

    Activation of non-cultivar-specific plant defense against attempted microbial infection is mediated through the recognition of pathogen-derived elicitors. Previously, we have identified a peptide fragment (Pep-13) within a 42-kDa cell wall transglutaminase from various Phytophthora species that triggers a multifacetted defense response in parsley cells. Many of these oomycete species have now been shown to possess another cell wall protein (24 kDa), that evoked the same pattern of responses in parsley as Pep-13. Unlike Pep-13, necrosis-inducing Phytophthora protein 1 (NPP1) purified from P. parasitica also induced hypersensitive cell death-like lesions in parsley. NPP1 structural homologs were found in oomycetes, fungi, and bacteria, but not in plants. Structure-activity relationship studies revealed the intact protein as well as two cysteine residues to be essential for elicitor activity. NPP1-mediated activation of pathogen defense in parsley does not employ the Pep-13 receptor. However, early induced cellular responses implicated in elicitor signal transmission (increased levels of cytoplasmic calcium, production of reactive oxygen species, MAP kinase activation) were stimulated by either elicitor, suggesting the existence of converging signaling pathways in parsley. Infiltration of NPP1 into leaves of Arabidopsis thaliana Col-0 plants resulted in transcript accumulation of pathogenesis-related (PR) genes, production of ROS and ethylene, callose apposition, and HR-like cell death. NPP1-mediated induction of the PR1 gene is salicylic acid-dependent, and, unlike the P. syringae pv. tomato DC3000(avrRpm1)-induced PR1 gene expression, requires both functional NDR1 and PAD4. In summary, Arabidopsis plants infiltrated with NPP1 constitute an experimental system that is amenable to forward genetic approaches aiming at the dissection of signaling pathways implicated in the activation of non-cultivar-specific plant defense.

  6. Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants.

    PubMed

    Lin, Xian Yong; Ye, Yi Quan; Fan, Shi Kai; Jin, Chong Wei; Zheng, Shao Jian

    2016-02-01

    Previous studies have identified that auxins acts upstream of nitric oxide in regulating iron deficiency responses in roots, but the upstream signaling molecule of auxins remains unknown. In this study, we showed that Fe deficiency increased sucrose (Suc) level in roots of Arabidopsis (Arabidopsis thaliana). Exogenous application of Suc further stimulated Fe deficiency-induced ferric-chelate-reductase (FCR) activity and expression of Fe acquisition-related genes FRO2, IRT1, and FIT in roots. The opposite patterns were observed in the dark treatment. In addition, FCR activity and expression of Fe acquisition-related genes were higher in the Suc high-accumulating transgenic plant 35S::SUC2 but were lower in the Suc low-accumulating mutant suc2-5 compared with wild-type plants under Fe-deficient conditions. Consequently, Fe deficiency tolerance was enhanced in 35S::SUC2 but was compromised in suc2-5. Exogenous Suc also increased root β-glucuronidase (GUS) activity in auxin-inducible reporter DR5-GUS transgenic plants under Fe deficiency. However, exogenous Suc failed to increase FCR activity and expression of Fe acquisition-related genes in the auxin transport-impaired mutants aux1-7 and pin1-1 as well as in the wild-type plants treated with an auxin transport inhibitor under Fe deficiency. In summary, we found that increased Suc accumulation is required for regulating Fe deficiency responses in plants, with auxins acting downstream in transmitting the Fe deficiency signal.

  7. Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants1

    PubMed Central

    Lin, Xian Yong; Ye, Yi Quan; Fan, Shi Kai

    2016-01-01

    Previous studies have identified that auxins acts upstream of nitric oxide in regulating iron deficiency responses in roots, but the upstream signaling molecule of auxins remains unknown. In this study, we showed that Fe deficiency increased sucrose (Suc) level in roots of Arabidopsis (Arabidopsis thaliana). Exogenous application of Suc further stimulated Fe deficiency-induced ferric-chelate-reductase (FCR) activity and expression of Fe acquisition-related genes FRO2, IRT1, and FIT in roots. The opposite patterns were observed in the dark treatment. In addition, FCR activity and expression of Fe acquisition-related genes were higher in the Suc high-accumulating transgenic plant 35S::SUC2 but were lower in the Suc low-accumulating mutant suc2-5 compared with wild-type plants under Fe-deficient conditions. Consequently, Fe deficiency tolerance was enhanced in 35S::SUC2 but was compromised in suc2-5. Exogenous Suc also increased root β-glucuronidase (GUS) activity in auxin-inducible reporter DR5-GUS transgenic plants under Fe deficiency. However, exogenous Suc failed to increase FCR activity and expression of Fe acquisition-related genes in the auxin transport-impaired mutants aux1-7 and pin1-1 as well as in the wild-type plants treated with an auxin transport inhibitor under Fe deficiency. In summary, we found that increased Suc accumulation is required for regulating Fe deficiency responses in plants, with auxins acting downstream in transmitting the Fe deficiency signal. PMID:26644507

  8. Purification of recombinant tissue plasminogen activator (rtPA) protein from transplastomic tobacco plants.

    PubMed

    Abdoli Nasab, Maryam; Jalali Javaran, Mokhtar; Cusido, Rosa M; Palazon, Javier

    2016-11-01

    Plants are low cost platforms for the production of recombinant proteins, but their complexity renders the purification of plant recombinant proteins more difficult than proteins expressed in yeast or bacteria. Plastid transformation enables high-level expression of foreign genes and the accumulation of recombinant proteins in plastid organelles. Histidine (His) tags are widely used for affinity purification of recombinant proteins in a nickel column. The human tissue-type plasminogen activator (tPA) is one of the most important pharmaceutical recombinant proteins involved in the breakdown of blood clots in different parts of the body. The truncated form of the tissue plasminogen activator (K2S) has a longer plasma half-life, better diffusion into the clot, and higher fibrinolytic activity. In a construct designed to insert the K2S gene in the tobacco chloroplast, the sequence of six histidines and a factor Xa protease site was fused to the C-terminus of the K2S protein. The presence and amount of tPA recombinant protein in transplastomic tobacco plants was estimated by ELISA analysis using a specific antibody. The protein was purified from total soluble protein, insoluble protein aggregates and the protein was extracted from the isolated chloroplast using nickel resin and a chromatography column. After digestion of the purified protein with factor Xa, the presence of the purified tPA protein was confirmed by western blot analysis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Involvement of ethylene in alleviation of Cd toxicity by NaCl in tobacco plants.

    PubMed

    Zhang, Binglin; Shang, Shenghua; Jabeen, Zahra; Zhang, Guoping

    2014-03-01

    The possible involvement of ethylene in alleviating cadmium (Cd) toxicity by NaCl was investigated because our previous experiments showed that a low concentration of NaCl could alleviate Cd toxicity of tobacco plants. Tobacco plants exposed to the treatment of a combination of Cd-NaCl exhibited more vigorous growth than did those exposed to the treatment of Cd stress alone, as reflected by greater biomass, longer roots, taller shoots, larger SPAD values and higher photosynthetic rates. The results also indicated that it is Na(+), rather than Cl(-), that alleviates Cd toxicity. Cd-NaCl treatments enhanced and inhibited ethylene production in roots and in leaves, respectively, in comparison with the plants exposed to Cd alone. However, the exogenous application of ethylene did not improve root growth under Cd exposure, indicating that ethylene is not directly involved in the rooting process. It may be assumed that the addition of NaCl into the solution containing Cd regulates root growth by mediating ethylene synthesis.

  10. Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress.

    PubMed

    Harris, M O; Friesen, T L; Xu, S S; Chen, M S; Giron, D; Stuart, J J

    2015-02-01

    In this review, we argue for a research initiative on wheat's responses to biotic stress. One goal is to begin a conversation between the disparate communities of plant pathology and entomology. Another is to understand how responses to a variety of agents of biotic stress are integrated in an important crop. We propose gene-for-gene interactions as the focus of the research initiative. On the parasite's side is an Avirulence (Avr) gene that encodes one of the many effector proteins the parasite applies to the plant to assist with colonization. On the plant's side is a Resistance (R) gene that mediates a surveillance system that detects the Avr protein directly or indirectly and triggers effector-triggered plant immunity. Even though arthropods are responsible for a significant proportion of plant biotic stress, they have not been integrated into important models of plant immunity that come from plant pathology. A roadblock has been the absence of molecular evidence for arthropod Avr effectors. Thirty years after this evidence was discovered in a plant pathogen, there is now evidence for arthropods with the cloning of the Hessian fly's vH13 Avr gene. After reviewing the two models of plant immunity, we discuss how arthropods could be incorporated. We end by showing features that make wheat an interesting system for plant immunity, including 479 resistance genes known from agriculture that target viruses, bacteria, fungi, nematodes, insects, and mites. It is not likely that humans will be subsisting on Arabidopsis in the year 2050. It is time to start understanding how agricultural plants integrate responses to biotic stress. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. Arbuscular mycorrhizal fungi reduce growth and infect roots of the non-host plant Arabidopsis thaliana.

    PubMed

    Veiga, Rita S L; Faccio, Antonella; Genre, Andrea; Pieterse, Corné M J; Bonfante, Paola; van der Heijden, Marcel G A

    2013-11-01

    The arbuscular mycorrhizal (AM) symbiosis is widespread throughout the plant kingdom and important for plant nutrition and ecosystem functioning. Nonetheless, most terrestrial ecosystems also contain a considerable number of non-mycorrhizal plants. The interaction of such non-host plants with AM fungi (AMF) is still poorly understood. Here, in three complementary experiments, we investigated whether the non-mycorrhizal plant Arabidopsis thaliana, the model organism for plant molecular biology and genetics, interacts with AMF. We grew A. thaliana alone or together with a mycorrhizal host species (either Trifolium pratense or Lolium multiflorum) in the presence or absence of the AMF Rhizophagus irregularis. Plants were grown in a dual-compartment system with a hyphal mesh separating roots of A. thaliana from roots of the host species, avoiding direct root competition. The host plants in the system ensured the presence of an active AM fungal network. AM fungal networks caused growth depressions in A. thaliana of more than 50% which were not observed in the absence of host plants. Microscopy analyses revealed that R. irregularis supported by a host plant was capable of infecting A. thaliana root tissues (up to 43% of root length colonized), but no arbuscules were observed. The results reveal high susceptibility of A. thaliana to R. irregularis, suggesting that A. thaliana is a suitable model plant to study non-host/AMF interactions and the biological basis of AM incompatibility. © 2013 John Wiley & Sons Ltd.

  12. Constitutive expression of mammalian nitric oxide synthase in tobacco plants triggers disease resistance to pathogens.

    PubMed

    Chun, Hyun Jin; Park, Hyeong Cheol; Koo, Sung Cheol; Lee, Ju Huck; Park, Chan Young; Choi, Man Soo; Kang, Chang Ho; Baek, Dongwon; Cheong, Yong Hwa; Yun, Dae-Jin; Chung, Woo Sik; Cho, Moo Je; Kim, Min Chul

    2012-11-01

    Nitric oxide (NO) is known for its role in the activation of plant defense responses. To examine the involvement and mode of action of NO in plant defense responses, we introduced calmodulin-dependent mammalian neuronal nitric oxide synthase (nNOS), which controls the CaMV35S promoter, into wild-type and NahG tobacco plants. Constitutive expression of nNOS led to NO production and triggered spontaneous induction of leaf lesions. Transgenic plants accumulated high amounts of H(2)O(2), with catalase activity lower than that in the wild type. nNOS transgenic plants contained high levels of salicylic acid (SA), and they induced an array of SA-, jasmonic acid (JA)-, and/or ethylene (ET)-related genes. Consequently, NahG co-expression blocked the induction of systemic acquired resistance (SAR)-associated genes in transgenic plants, implying SA is involved in NO-mediated induction of SAR genes. The transgenic plants exhibited enhanced resistance to a spectrum of pathogens, including bacteria, fungi, and viruses. Our results suggest a highly ranked regulatory role for NO in SA-, JA-, and/or ET-dependent pathways that lead to disease resistance.

  13. Constitutive Expression of Mammalian Nitric Oxide Synthase in Tobacco Plants Triggers Disease Resistance to Pathogens

    PubMed Central

    Chun, Hyun Jin; Park, Hyeong Cheol; Koo, Sung Cheol; Lee, Ju Huck; Park, Chan Young; Choi, Man Soo; Kang, Chang Ho; Baek, Dongwon; Cheong, Yong Hwa; Yun, Dae-Jin; Chung, Woo Sik; Cho, Moo Je; Kim, Min Chul

    2012-01-01

    Nitric oxide (NO) is known for its role in the activation of plant defense responses. To examine the involvement and mode of action of NO in plant defense responses, we introduced calmodulin-dependent mammalian neuronal nitric oxide synthase (nNOS), which controls the CaMV35S promoter, into wild-type and NahG tobacco plants. Constitutive expression of nNOS led to NO production and triggered spontaneous induction of leaf lesions. Transgenic plants accumulated high amounts of H2O2, with catalase activity lower than that in the wild type. nNOS transgenic plants contained high levels of salicylic acid (SA), and they induced an array of SA-, jasmonic acid (JA)-, and/or ethylene (ET)-related genes. Consequently, NahG co-expression blocked the induction of systemic acquired resistance (SAR)-associated genes in transgenic plants, implying SA is involved in NO-mediated induction of SAR genes. The transgenic plants exhibited enhanced resistance to a spectrum of pathogens, including bacteria, fungi, and viruses. Our results suggest a highly ranked regulatory role for NO in SA-, JA-, and/or ET-dependent pathways that lead to disease resistance. PMID:23124383

  14. A Contribution to Identification of Novel Regulators of Plant Response to Sulfur Deficiency: Characteristics of a Tobacco Gene UP9C, Its Protein Product and the Effects of UP9C Silencing

    PubMed Central

    Lewandowska, Małgorzata; Wawrzyńska, Anna; Moniuszko, Grzegorz; Łukomska, Jolanta; Zientara, Katarzyna; Piecho, Marta; Hodurek, Paweł; Zhukov, Igor; Liszewska, Frantz; Nikiforova, Victoria; Sirko, Agnieszka

    2010-01-01

    Extensive changes in plant transcriptome and metabolome have been observed by numerous research groups after transferring plants from optimal conditions to sulfur (S) deficiency. Despite intensive studies and recent important achievements, like identification of SLIM1/EIL3 as a major transcriptional regulator of the response to S-deficiency, many questions concerning other elements of the regulatory network remain unanswered. Investigations of genes with expression regulated by S-deficiency stress encoding proteins of unknown function might help to clarify these problems. This study is focused on the UP9C gene and the UP9-like family in tobacco. Homologs of these genes exist in other plant species, including a family of four genes of unknown function in Arabidopsis thaliana (LSU1-4), of which two were reported as strongly induced by S-deficit and to a lesser extent by salt stress and nitrate limitation. Conservation of the predicted structural features, such as coiled coil region or nuclear localization signal, suggests that these proteins might have important functions possibly mediated by interactions with other proteins. Analysis of transgenic tobacco plants with silenced expression of UP9-like genes strongly argues for their significant role in regulation of plant response to S-deficit. Although our study shows that the UP9-like proteins are important components of such response and they might be also required during other stresses, their molecular functions remain a mystery. PMID:20147370

  15. A contribution to identification of novel regulators of plant response to sulfur deficiency: characteristics of a tobacco gene UP9C, its protein product and the effects of UP9C silencing.

    PubMed

    Lewandowska, Malgorzata; Wawrzynska, Anna; Moniuszko, Grzegorz; Lukomska, Jolanta; Zientara, Katarzyna; Piecho, Marta; Hodurek, Pawel; Zhukov, Igor; Liszewska, Frantz; Nikiforova, Victoria; Sirko, Agnieszka

    2010-03-01

    Extensive changes in plant transcriptome and metabolome have been observed by numerous research groups after transferring plants from optimal conditions to sulfur (S) deficiency. Despite intensive studies and recent important achievements, like identification of SLIM1/EIL3 as a major transcriptional regulator of the response to S-deficiency, many questions concerning other elements of the regulatory network remain unanswered. Investigations of genes with expression regulated by S-deficiency stress encoding proteins of unknown function might help to clarify these problems. This study is focused on the UP9C gene and the UP9-like family in tobacco. Homologs of these genes exist in other plant species, including a family of four genes of unknown function in Arabidopsis thaliana (LSU1-4), of which two were reported as strongly induced by S-deficit and to a lesser extent by salt stress and nitrate limitation. Conservation of the predicted structural features, such as coiled coil region or nuclear localization signal, suggests that these proteins might have important functions possibly mediated by interactions with other proteins. Analysis of transgenic tobacco plants with silenced expression of UP9-like genes strongly argues for their significant role in regulation of plant response to S-deficit. Although our study shows that the UP9-like proteins are important components of such response and they might be also required during other stresses, their molecular functions remain a mystery.

  16. Regulation of epinasty induced by 2,4-dichlorophenoxyacetic acid in pea and Arabidopsis plants.

    PubMed

    Pazmiño, D M; Rodríguez-Serrano, M; Sanz, M; Romero-Puertas, M C; Sandalio, L M

    2014-07-01

    The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) causes uncontrolled cell division and malformed growth in plants, giving rise to leaf epinasty and stem curvature. In this study, mechanisms involved in the regulation of leaf epinasty induced by 2,4-D were studied using different chemicals involved in reactive oxygen species (ROS) accumulation (diphenyleniodonium, butylated hydroxyanisole, EDTA, allopurinol), calcium channels (LaCl3), protein phosphorylation (cantharidin, wortmannin) and ethylene emission/perception (aminoethoxyvinyl glycine, AgNO3). The effect of these compounds on the epinasty induced by 2,4-D was analysed in shoots and leaf strips from pea plants. For further insight into the effect of 2,4-D, studies were also made in Arabidopsis mutants deficient in ROS production (rbohD, rbohF, xdh), ethylene (ein 3-1, ctr 1-1, etr 1-1), abscisic acid (aba 3.1), and jasmonic acid (coi 1.1, jar 1.1, opr 3) pathways. The results suggest that ROS production, mainly ·OH, is essential in the development of epinasty triggered by 2,4-D. Epinasty was also found to be regulated by Ca2+, protein phosphorylation and ethylene, although all these factors act downstream of ROS production. The use of Arabidopsis mutants appears to indicate that abscisic and jasmonic acid are not involved in regulating epinasty, although they could be involved in other symptoms induced by 2,4-D.

  17. Arabidopsis protein phosphatase DBP1 nucleates a protein network with a role in regulating plant defense.

    PubMed

    Carrasco, José Luis; Castelló, María José; Naumann, Kai; Lassowskat, Ines; Navarrete-Gómez, Marisa; Scheel, Dierk; Vera, Pablo

    2014-01-01

    Arabidopsis thaliana DBP1 belongs to the plant-specific family of DNA-binding protein phosphatases. Although recently identified as a novel host factor mediating susceptibility to potyvirus, little is known about DBP1 targets and partners and the molecular mechanisms underlying its function. Analyzing changes in the phosphoproteome of a loss-of-function dbp1 mutant enabled the identification of 14-3-3λ isoform (GRF6), a previously reported DBP1 interactor, and MAP kinase (MAPK) MPK11 as components of a small protein network nucleated by DBP1, in which GRF6 stability is modulated by MPK11 through phosphorylation, while DBP1 in turn negatively regulates MPK11 activity. Interestingly, grf6 and mpk11 loss-of-function mutants showed altered response to infection by the potyvirus Plum pox virus (PPV), and the described molecular mechanism controlling GRF6 stability was recapitulated upon PPV infection. These results not only contribute to a better knowledge of the biology of DBP factors, but also of MAPK signalling in plants, with the identification of GRF6 as a likely MPK11 substrate and of DBP1 as a protein phosphatase regulating MPK11 activity, and unveils the implication of this protein module in the response to PPV infection in Arabidopsis.

  18. The rice Mybleu transcription factor increases tolerance to oxygen deprivation in Arabidopsis plants.

    PubMed

    Mattana, Monica; Vannini, Candida; Espen, Luca; Bracale, Marcella; Genga, Annamaria; Marsoni, Milena; Iriti, Marcello; Bonazza, Veronica; Romagnoli, Francesco; Baldoni, Elena; Coraggio, Immacolata; Locatelli, Franca

    2007-09-01

    Mybleu is a natural incomplete transcription factor of rice (Oryza sativa), consisting of a partial Myb repeat followed by a short leucine zipper. We previously showed its localization to the apical region of rice roots and coleoptiles. Specifically, in coleoptiles, Mybleu is expressed under both aerobic and anaerobic conditions, whereas in roots, it is expressed only under aerobic conditions. Mybleu is able to dimerize with canonical leucine zippers and to activate transcription selectively. To investigate Mybleu function in vivo, we transformed Arabidopsis thaliana and evaluated several morphological, physiological and biochemical parameters. In agreement with a hypothesized role of Mybleu in cell elongation in the differentiation zone, we found that the constitutive expression of this transcription factor in Arabidopsis induced elongation in the primary roots and in the internodal region of the floral stem; we also observed a modification of the root apex morphology in transformed lines. Based on the high expression of Mybleu in anaerobic rice coleoptiles, we studied the role of this transcription factor in transgenic plants grown under low-oxygen conditions. We found that overexpression of this transcription factor increased tolerance to oxygen deficit. In transgenic plants, this effect may depend both on the maintenance of a higher metabolism during stress and on the higher expression levels of certain genes involved in the anaerobic response.

  19. Arabidopsis female gametophyte gene expression map reveals similarities between plant and animal gametes.

    PubMed

    Wuest, Samuel E; Vijverberg, Kitty; Schmidt, Anja; Weiss, Manuel; Gheyselinck, Jacqueline; Lohr, Miriam; Wellmer, Frank; Rahnenführer, Jörg; von Mering, Christian; Grossniklaus, Ueli

    2010-03-23

    The development of multicellular organisms is controlled by differential gene expression whereby cells adopt distinct fates. A spatially resolved view of gene expression allows the elucidation of transcriptional networks that are linked to cellular identity and function. The haploid female gametophyte of flowering plants is a highly reduced organism: at maturity, it often consists of as few as three cell types derived from a common precursor [1, 2]. However, because of its inaccessibility and small size, we know little about the molecular basis of cell specification and differentiation in the female gametophyte. Here we report expression profiles of all cell types in the mature Arabidopsis female gametophyte. Differentially expressed posttranscriptional regulatory modules and metabolic pathways characterize the distinct cell types. Several transcription factor families are overrepresented in the female gametophyte in comparison to other plant tissues, e.g., type I MADS domain, RWP-RK, and reproductive meristem transcription factors. PAZ/Piwi-domain encoding genes are upregulated in the egg, indicating a role of epigenetic regulation through small RNA pathways-a feature paralleled in the germline of animals [3]. A comparison of human and Arabidopsis egg cells for enrichment of functional groups identified several similarities that may represent a consequence of coevolution or ancestral gametic features. 2010 Elsevier Ltd. All rights reserved.

  20. The Arabidopsis outward K+ channel GORK is involved in regulation of stomatal movements and plant transpiration

    PubMed Central

    Hosy, Eric; Vavasseur, Alain; Mouline, Karine; Dreyer, Ingo; Gaymard, Frédéric; Porée, Fabien; Boucherez, Jossia; Lebaudy, Anne; Bouchez, David; Véry, Anne-Aliénor; Simonneau, Thierry; Thibaud, Jean-Baptiste; Sentenac, Hervé

    2003-01-01

    Microscopic pores present in the epidermis of plant aerial organs, called stomata, allow gas exchanges between the inner photosynthetic tissue and the atmosphere. Regulation of stomatal aperture, preventing excess transpirational vapor loss, relies on turgor changes of two highly differentiated epidermal cells surrounding the pore, the guard cells. Increased guard cell turgor due to increased solute accumulation results in stomatal opening, whereas decreased guard cell turgor due to decreased solute accumulation results in stomatal closing. Here we provide direct evidence, based on reverse genetics approaches, that the Arabidopsis GORK Shaker gene encodes the major voltage-gated outwardly rectifying K+ channel of the guard cell membrane. Expression of GORK dominant negative mutant polypeptides in transgenic Arabidopsis was found to strongly reduce outwardly rectifying K+ channel activity in the guard cell membrane, and disruption of the GORK gene (T-DNA insertion knockout mutant) fully suppressed this activity. Bioassays on epidermal peels revealed that disruption of GORK activity resulted in impaired stomatal closure in response to darkness or the stress hormone azobenzenearsonate. Transpiration measurements on excised rosettes and intact plants (grown in hydroponic conditions or submitted to water stress) revealed that absence of GORK activity resulted in increased water consumption. The whole set of data indicates that GORK is likely to play a crucial role in adaptation to drought in fluctuating environments. PMID:12671068

  1. Three SAUR proteins SAUR76, SAUR77 and SAUR78 promote plant growth in Arabidopsis

    PubMed Central

    Li, Zhi-Gang; Chen, Hao-Wei; Li, Qing-Tian; Tao, Jian-Jun; Bian, Xiao-Hua; Ma, Biao; Zhang, Wan-Ke; Chen, Shou-Yi; Zhang, Jin-Song

    2015-01-01

    Ethylene perceived by a family of five receptors regulates many developmental processes in Arabidopsis. Here we conducted the yeast two-hybrid assay to screen for additional unidentified proteins that interact with subfamily II ethylene receptor ETR2. Three SAUR proteins, named SAUR76, 77 and 78, were identified to associate with both ETR2 and EIN4 in different assays. Interaction of SAUR76 and SAUR78 with ETR2 was further verified by co-immunoprecipitation and bimolecular fluorescence complementation (BiFC) assays. Expressions of SAUR76-78 are induced by auxin and ethylene treatments. Compared with wild type, SAUR-overexpressing plants exhibit reduced ethylene sensitivity, while SAUR-RNAi lines exhibit enhanced ethylene sensitivity. Overexpressing the three SAURs partially complements the phenotype of subfamily II ethylene receptor loss-of-function double mutant etr2-3ein4-4, which has increased ethylene response and small cotyledon and rosette. saur76 mutation partially suppresses the reduced ethylene sensitivity of etr2-2. SAUR76/78 proteins are regulated by 26S proteasome system and larger tag increases their protein stability. These findings suggest that SAUR76-78 may affect ethylene receptor signaling and promote plant growth in Arabidopsis. PMID:26207341

  2. The interconversion of UDP-arabinopyranose and UDP-arabinofuranose is indispensable for plant development in Arabidopsis.

    PubMed

    Rautengarten, Carsten; Ebert, Berit; Herter, Thomas; Petzold, Christopher J; Ishii, Tadashi; Mukhopadhyay, Aindrila; Usadel, Björn; Scheller, Henrik Vibe

    2011-04-01

    L-Ara, an important constituent of plant cell walls, is found predominantly in the furanose rather than in the thermodynamically more stable pyranose form. Nucleotide sugar mutases have been demonstrated to interconvert UDP-Larabinopyranose (UDP-Arap) and UDP-L-arabinofuranose (UDP-Araf) in rice (Oryza sativa). These enzymes belong to a small gene family encoding the previously named Reversibly Glycosylated Proteins (RGPs). RGPs are plant-specific cytosolic proteins that tend to associate with the endomembrane system. In Arabidopsis thaliana, the RGP protein family consists of five closely related members. We characterized all five RGPs regarding their expression pattern and subcellular localizations in transgenic Arabidopsis plants. Enzymatic activity assays of recombinant proteins expressed in Escherichia coli identified three of the Arabidopsis RGP protein family members as UDP-L-Ara mutases that catalyze the formation of UDP-Araf from UDP-Arap. Coimmunoprecipitation and subsequent liquid chromatography-electrospray ionization-tandem mass spectrometry analysis revealed a distinct interaction network between RGPs in different Arabidopsis organs. Examination of cell wall polysaccharide preparations from RGP1 and RGP2 knockout mutants showed a significant reduction in total L-Ara content (12–31%) compared with wild-type plants. Concomitant downregulation of RGP1 and RGP2 expression results in plants almost completely deficient in cell wall–derived L-Ara and exhibiting severe developmental defects.

  3. Overexpression of ARGOS Genes Modifies Plant Sensitivity to Ethylene, Leading to Improved Drought Tolerance in Both Arabidopsis and Maize.

    PubMed

    Shi, Jinrui; Habben, Jeffrey E; Archibald, Rayeann L; Drummond, Bruce J; Chamberlin, Mark A; Williams, Robert W; Lafitte, H Renee; Weers, Ben P

    2015-09-01

    Lack of sufficient water is a major limiting factor to crop production worldwide, and the development of drought-tolerant germplasm is needed to improve crop productivity. The phytohormone ethylene modulates plant growth and development as well as plant response to abiotic stress. Recent research has shown that modifying ethylene biosynthesis and signaling can enhance plant drought tolerance. Here, we report novel negative regulators of ethylene signal transduction in Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). These regulators are encoded by the ARGOS gene family. In Arabidopsis, overexpression of maize ARGOS1 (ZmARGOS1), ZmARGOS8, Arabidopsis ARGOS homolog ORGAN SIZE RELATED1 (AtOSR1), and AtOSR2 reduced plant sensitivity to ethylene, leading to enhanced drought tolerance. RNA profiling and genetic analysis suggested that the ZmARGOS1 transgene acts between an ethylene receptor and CONSTITUTIVE TRIPLE RESPONSE1 in the ethylene signaling pathway, affecting ethylene perception or the early stages of ethylene signaling. Overexpressed ZmARGOS1 is localized to the endoplasmic reticulum and Golgi membrane, where the ethylene receptors and the ethylene signaling protein ETHYLENE-INSENSITIVE2 and REVERSION-TO-ETHYLENE SENSITIVITY1 reside. In transgenic maize plants, overexpression of ARGOS genes also reduces ethylene sensitivity. Moreover, field testing showed that UBIQUITIN1:ZmARGOS8 maize events had a greater grain yield than nontransgenic controls under both drought stress and well-watered conditions.

  4. Development of large DNA methods for plants: molecular cloning of large segments of Arabidopsis and carrot DNA into yeast.

    PubMed Central

    Guzmán, P; Ecker, J R

    1988-01-01

    Procedures for the preparation, analysis and cloning of large DNA molecules from two different plant species are described. Arabidopsis and carrot protoplasts were used for the preparation of large DNA molecules in agarose "plugs" or in solution. Pulsed-field gel electrophoresis (PFGE) analysis of large plant DNA preparations using a contour-clamped homogeneous field (CHEF) apparatus indicated that the size of the DNA was at least 12 Mb. Large DNA preparations were shown to be useful for restriction enzyme analysis of the Arabidopsis genome using both frequent and infrequent cutting enzymes and for the molecular cloning of large segments of DNA into yeast using artificial chromosome (YAC) vectors. PFGE and blot hybridization analysis of Arabidopsis and carrot DNA-containing YACs indicated that both unique and highly repeated DNA sequences were represented in these libraries. Images PMID:3060856

  5. Analysis of the transgenerational iron deficiency stress memory in Arabidopsis thaliana plants.

    PubMed

    Murgia, Irene; Giacometti, Sonia; Balestrazzi, Alma; Paparella, Stefania; Pagliano, Cristina; Morandini, Piero

    2015-01-01

    We investigated the existence of the transgenerational memory of iron (Fe) deficiency stress, in Arabidopsis thaliana. Plants were grown under Fe deficiency/sufficiency, and so were their offspring. The frequency of somatic homologous recombination (SHR) events, of DNA strand breaks as well as the expression of the transcription elongation factor TFIIS-like gene increase when plants are grown under Fe deficiency. However, SHR frequency, DNA strand break events, and TFIIS-like gene expression do not increase further when plants are grown for more than one generation under the same stress, and furthermore, they decrease back to control values within two succeeding generations grown under control conditions, regardless of the Fe deficiency stress history of the mother plants. Seedlings produced from plants grown under Fe deficiency evolve more oxygen than control seedlings, when grown under Fe sufficiency: however, this trait is not associated with any change in the protein profile of the photosynthetic apparatus and is not transmitted to more than one generation. Lastly, plants grown for multiple generations under Fe deficiency produce seeds with greater longevity: however, this trait is not inherited in offspring generations unexposed to stress. These findings suggest the existence of multiple-step control of mechanisms to prevent a genuine and stable transgenerational transmission of Fe deficiency stress memory, with the tightest control on DNA integrity.

  6. Increase of homologous recombination frequency in vascular tissue of Arabidopsis plants exposed to salt stress.

    PubMed

    Boyko, Alex; Hudson, Darryl; Bhomkar, Prasanna; Kathiria, Palak; Kovalchuk, Igor

    2006-06-01

    Here we analyzed the influence of salt stress on plant genome stability. Homologous recombination events were detected in transgenic Arabidopsis plants that carried in their genome a beta-glucuronidase recombination marker. Recombination events were scored as blue sectors using a stereo microscope. Exposure to 50 mM salt resulted in a 3.0-fold increase in recombination frequency. To analyze the organ and tissue specificity of recombination events, we examined cross-sections of leaves, stems and roots. We found that nearly 30% of recombination events in plants grown under normal conditions and nearly 50% of events in plants grown on salt were undetected by the conventional method. Most of the recombination events represented a cluster/group of cells (12 on average), although events with single cells were also detected. Recombination events were very frequent in leaf mesophyll cells. On average, individual recombination events located on leaves contained more cells than events located on roots or stems. Analysis of recombination events in cross-sectioned tissue of salt-treated plants revealed a shift in the distribution of recombination events towards the vascular tissue. We discuss the significance of the finding for plant stress physiology.

  7. Competing mechanisms for perfluoroalkyl acid accumulation in plants revealed using an Arabidopsis model system.

    PubMed

    Müller, Claudia E; LeFevre, Gregory H; Timofte, Anca E; Hussain, Fatima A; Sattely, Elizabeth S; Luthy, Richard G

    2016-05-01

    Perfluoroalkyl acids (PFAAs) bioaccumulate in plants, presenting a human exposure route if present in irrigation water. Curiously, accumulation of PFAAs in plant tissues is greatest for both the short-chain and long-chain PFAAs, generating a U-shaped relationship with chain length. In the present study, the authors decouple competing mechanisms of PFAA accumulation using a hydroponic model plant system (Arabidopsis thaliana) exposed to a suite of 10 PFAAs to determine uptake, depuration, and translocation kinetics. Rapid saturation of root concentrations occurred for all PFAAs except perfluorobutanoate, the least-sorptive (shortest-chain) PFAA. Shoot concentrations increased continuously, indicating that PFAAs are efficiently transported and accumulate in shoots. Tissue concentrations of PFAAs during depuration rapidly declined in roots but remained constant in shoots, demonstrating irreversibility of the translocation process. Root and shoot concentration factors followed the U-shaped trend with perfluoroalkyl chain length; however, when normalized to dead-tissue sorption, this relationship linearized. The authors therefore introduce a novel term, the "sorption normalized concentration factor," to describe PFAA accumulation in plants; because of their hydrophobicity, sorption is the determining factor for long-chain PFAAs, whereas the shortest-chain PFAAs are most effectively transported in the plant. The present study provides a mechanistic explanation for previously unexplained PFAA accumulation trends in plants and suggests that shorter-chained PFAAs may bioaccumulate more readily in edible portions. © 2015 SETAC.

  8. Arabidopsis thaliana, a plant model organism for the neuronal microtubule cytoskeleton?

    PubMed

    Gardiner, John; Marc, Jan

    2011-01-01

    The microtubule cytoskeleton is an important component of both neuronal cells and plant cells. While there are large differences in the function of microtubules between the two groups of organisms, for example plants coordinate the ordered deposition of cellulose through the microtubule cytoskeleton, there are also some notable similarities. It is suggested that Arabidopsis thaliana, with its superior availability of knockout lines, may be a suitable model organism for some aspects of the neuronal microtubule cytoskeleton. Some cellular processes that involve the neuronal microtubule cytoskeleton including neurotransmitter signalling and neurotrophic support may have homologous processes in plant cells. A number of microtubule-associated proteins (MAPs) are conserved, including katanin, EB1, CLASP, spastin, gephyrin, CRIPT, Atlastin/RHD3, and ELP3. As a demonstration of the usefulness of a plant model system for neuronal biology, an analysis of plant tubulin-binding proteins was used to show that Charcot-Marie-Tooth disease type 2D and spinal muscular atrophy may be due to microtubule dysfunction and suggest that indeed the plant microtubule cytoskeleton may be particularly similar to that of motor neurons as both are heavily reliant upon motor proteins.

  9. Quantifying the dynamics of light tolerance in Arabidopsis plants during ontogenesis.

    PubMed

    Carvalho, Fabricio E L; Ware, Maxwell A; Ruban, Alexander V

    2015-12-01

    The amount of light plants can tolerate during different phases of ontogenesis remains largely unknown. This was addressed here employing a novel methodology that uses the coefficient of photochemical quenching (qP) to assess the intactness of photosystem II reaction centres. Fluorescence quenching coefficients, total chlorophyll content and concentration of anthocyanins were determined weekly during the juvenile, adult, reproductive and senescent phases of plant ontogenesis. This enabled quantification of the protective effectiveness of non-photochemical fluorescence quenching (NPQ) and determination of light tolerance. The light intensity that caused photoinhibition in 50% of leaf population increased from ∼70 μmol m(-2)  s(-1) , for 1-week-old seedlings, to a maximum of 1385 μmol m(-2)  s(-1) for 8-week-old plants. After 8 weeks, the tolerated light intensity started to gradually decline, becoming only 332 μmol m(-2)  s(-1) for 13-week-old plants. The dependency of light tolerance on plant age was well-related to the amplitude of protective NPQ (pNPQ) and the electron transport rates (ETRs). Light tolerance did not, however, show a similar trend to chlorophyll a/b ratios and content of anthocyanins. Our data suggest that pNPQ is crucial in defining the capability of high light tolerance by Arabidopsis plants during ontogenesis. © 2015 John Wiley & Sons Ltd.

  10. Human Norovirus and Its Surrogates Induce Plant Immune Response in Arabidopsis thaliana and Lactuca sativa.

    PubMed

    Markland, Sarah M; Bais, Harsh; Kniel, Kalmia E

    2017-08-01

    Human norovirus is the leading cause of foodborne illness worldwide with the majority of outbreaks linked to fresh produce and leafy greens. It is essential that we thoroughly understand the type of relationship and interactions that take place between plants and human norovirus to better utilize control strategies to reduce transmission of norovirus in the field onto plants harvested for human consumption. In this study the expression of gene markers for the salicylic acid (SA) and jasmonic acid (JA) plant defense pathways was measured and compared in romaine lettuce (Lactuca sativa) and Arabidopsis thaliana Col-0 plants that were inoculated with Murine Norovirus-1, Tulane Virus, human norovirus GII.4, or Hank's Balanced Salt Solution (control). Genes involving both the SA and JA pathways were expressed in both romaine lettuce and A. thaliana for all three viruses, as well as controls. Studies, including gene expression of SA- and JA-deficient A. thaliana mutant lines, suggest that the JA pathway is more likely involved in the plant immune response to human norovirus. This research provides the first pieces of information regarding how foodborne viruses interact with plants in the preharvest environment.

  11. Identification of plant defence regulators through transcriptional profiling of Arabidopsis thaliana cdd1 mutant.

    PubMed

    Swain, Swadhin; Singh, Nidhi; Nandi, Ashis Kumar

    2015-03-01

    A sustainable balance between defence and growth is essential for optimal fitness under pathogen stress. Plants activate immune response at the cost of normal metabolic requirements. Thus, plants that constitutively activate defence are deprived of growth. Arabidopsis thaliana mutant constitutive defence without defect in growth and development1 (cdd1) is an exception. The cdd1 mutant is constitutive for salicylic acid accumulation, signalling, and defence against biotrophic and hemibiotrophic pathogens, without having much impact on growth. Thus, cdd1 offers an ideal genetic background to identify novel regulators of plant defence. Here we report the differential gene expression profile between cdd1 and wild-type plants as obtained by microarray hybridization. Expression of several defence-related genes also supports constitutive activation of defence in cdd1. We screened T-DNA insertion mutant lines of selected genes, for resistance against virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Through bacterial resistance, callose deposition and pathogenesis-associated expression analyses, we identified four novel regulators of plant defence. Resistance levels in the mutants suggest that At2g19810 and [rom] At5g05790 are positive regulators, whereas At1g61370 and At3g42790 are negative regulators of plant defence against bacterial pathogens.

  12. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development

    SciTech Connect

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M.; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L.

    2016-07-06

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development.

  13. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development

    DOE PAGES

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; ...

    2016-07-06

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi andmore » is required for proper plant growth and development.« less

  14. Arabidopsis Thaliana and Zea Mays Data from the Plant Proteome Database (PPDB) at Cornell University

    DOE Data Explorer

    The main objective is to provide a centralized, curated, data deposit for predicted and experimentally determined proteins in Arabidopsis thaliana and maize (Zea mays), their annotated functions, as well as their experimental and predicted molecular and biophysical properties. Importantly, information from mass spectrometry-based identifications is available for each identified protein accession; this will allow the database user to determine the significance the experimental identification and also evaluate information of post-translational modification. Multiple search methods are provided so that the user can retrieve information based on gene identification number, functional annotation or various protein properties. Initiated in 2004, PPDB was originally dedicated to plant plastids, but has now expanded to the whole plant proteome. The database includes data generated in Cornell labs, external published data sets, and deposited data from contributors.[Taken from PPDB website at http://ppdb.tc.cornell.edu/introduction.aspx

  15. Plant growth homeostasis is controlled by the Arabidopsis BON1 and BAP1 genes

    PubMed Central

    Hua, Jian; Grisafi, Paula; Cheng, Shu-Hua; Fink, Gerald R.

    2001-01-01

    Wild-type Arabidopsis plants maintain a relatively constant size over a wide range of temperatures. Here we show that this homeostasis requires the BONZAI1 (BON1) gene because bon1 null mutants make miniature fertile plants at 22°C but have wild-type appearance at 28°C. The expression of BON1 and a BON1-associated protein (BAP1) is modulated by temperature. Thus BON1 and BAP1 may have a direct role in regulating cell expansion and cell division at lower temperatures. BON1 contains a Ca2+-dependent phospholipid-binding domain and is associated with the plasma membrane. It belongs to the copine gene family, which is conserved from protozoa to humans. Our data suggest that this gene family may function in the pathway of membrane trafficking in response to external conditions. PMID:11544183

  16. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development.

    PubMed

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L

    2016-07-06

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development.

  17. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development

    PubMed Central

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M.; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L.

    2016-01-01

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development. PMID:27381418

  18. Long-term protection against tobacco mosaic virus induced by the marine alga oligo-sulphated-galactan Poly-Ga in tobacco plants.

    PubMed

    Vera, Jeannette; Castro, Jorge; González, Alberto; Barrientos, Herna; Matsuhiro, Betty; Arce, Patricio; Zuñiga, Gustavo; Moenne, Alejandra

    2011-06-01

    In order to study the antiviral effect of the oligo-sulphated galactan Poly-Ga, the leaves of tobacco plants Xhanti(NN) were sprayed with water (control), with increasing concentrations of Poly-Ga, for increasing numbers of treatments or cultivated for increasing times after treatment. Control and treated plants were infected with tobacco mosaic virus (TMV) and the numbers of necrotic lesions were measured in infected leaves. The number of necrotic lesions decreased with increasing concentrations of Poly-Ga, with increasing numbers of treatments and with increasing time after treatment, indicating a long-term protection against TMV that mimicks vaccination. In addition, control Xhanti(nn) plants and plants treated with Poly-Ga and cultivated for increasing times after treatment were infected with TMV in the middle part of the plant, and the levels of TMV-capsid protein (CP) transcripts were measured in apical leaves. TMV-CP transcripts decreased in distant leaves, indicating that Poly-Ga induces systemic protection against TMV. The activities of the defence enzymes phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) and the amounts of several phenylpropanoid compounds (PPCs) were measured in control and treated plants without infection. A progressive increase in PAL activity was observed with increasing time after treatment, together with the accumulation of free and conjugated PPCs. In contrast, LOX activity remained unchanged. Interestingly, the increase in PAL activity showed a linear correlation with the decrease in necrotic lesions and the decrease in TMV-CP transcript level. Thus, Poly-Ga induced systemic and long-term protection against TMV in tobacco plants that is determined, at least in part, by a sustained activation of PAL and the accumulation of PPCs with potential antiviral activity.

  19. Expression of a calmodulin methylation mutant affects the growth and development of transgenic tobacco plants.

    PubMed Central

    Roberts, D M; Besl, L; Oh, S H; Masterson, R V; Schell, J; Stacey, G

    1992-01-01

    Transgenic plants were constructed that express two foreign calmodulins (VU-1 and VU-3 calmodulins) derived from a cloned synthetic calmodulin gene. VU-1 calmodulin, similar to endogenous plant calmodulin, possesses a lysine residue at position 115 and undergoes posttranslational methylation. VU-3 calmodulin is a site-directed mutant of VU-1 calmodulin that is identical in sequence except for the substitution of an arginine at position 115 and thus is incapable of methylation. Both calmodulin genes, under the control of the cauliflower mosaic virus 35S promoter, were expressed in transgenic tobacco. Foreign calmodulin protein accumulated in plant tissues to levels equivalent to that of the endogenous calmodulin. All transformed lines of VU-1 plants were indistinguishable from untransformed controls with respect to growth and development. However, all transformed lines of VU-3 plants were characterized by decreased stem internode growth, reduced seed production, and reduced seed and pollen viability. The data suggest that these phenotypes are the result of the expression of the calmodulin mutant rather than the position of transferred DNA insertion or the overall alteration of calmodulin levels. Analyses of the activity of the purified transgenic calmodulins suggest that calmodulin-dependent NAD kinase is among the potential targets that may have altered regulation in VU-3 transgenic plants. Images PMID:1325656

  20. Chloride regulates leaf cell size and water relations in tobacco plants

    PubMed Central

    Franco-Navarro, Juan D.; Brumós, Javier; Rosales, Miguel A.; Cubero-Font, Paloma; Talón, Manuel; Colmenero-Flores, José M.

    2016-01-01

    Chloride (Cl–) is a micronutrient that accumulates to macronutrient levels since it is normally available in nature and actively taken up by higher plants. Besides a role as an unspecific cell osmoticum, no clear biological roles have been explicitly associated with Cl– when accumulated to macronutrient concentrations. To address this question, the glycophyte tobacco (Nicotiana tabacum L. var. Habana) has been treated with a basal nutrient solution supplemented with one of three salt combinations containing the same cationic balance: Cl–-based (CL), nitrate-based (N), and sulphate+phosphate-based (SP) treatments. Under non-saline conditions (up to 5mM Cl–) and no water limitation, Cl– specifically stimulated higher leaf cell size and led to a moderate increase of plant fresh and dry biomass mainly due to higher shoot expansion. When applied in the 1–5mM range, Cl– played specific roles in regulating leaf osmotic potential and turgor, allowing plants to improve leaf water balance parameters. In addition, Cl– also altered water relations at the whole-plant level through reduction of plant transpiration. This was a consequence of a lower stomatal conductance, which resulted in lower water loss and greater photosynthetic and integrated water-use efficiency. In contrast to Cl–, these effects were not observed for essential anionic macronutrients such as nitrate, sulphate, and phosphate. We propose that the abundant uptake and accumulation of Cl– responds to adaptive functions improving water homeostasis in higher plants. PMID:26602947

  1. Exploration of horizontal gene transfer between transplastomic tobacco and plant-associated bacteria.

    PubMed

    Demanèche, Sandrine; Monier, Jean-Michel; Dugat-Bony, Eric; Simonet, Pascal

    2011-10-01

    The likelihood of gene transfer from transgenic plants to bacteria is dependent on the transgene copy number and on the presence of homologous sequences for recombination. The large number of chloroplast genomes in a plant cell as well as the prokaryotic origin of the transgene may thus significantly increase the likelihood of gene transfer from transplastomic plants to bacteria. In order to assess the probability of such a transfer, bacterial isolates, screened for their ability to colonize decaying tobacco plant tissue and possessing DNA sequence similarity to the chloroplastic genes accD and rbcL flanking the transgene (aadA), were tested for their ability to take up extracellular DNA (broad host-range pBBR1MCS-3-derived plasmid, transplastomic plant DNA and PCR products containing the genes accD-aadA-rbcL) by natural or electrotransformation. The results showed that among the 16 bacterial isolates tested, six were able to accept foreign DNA and acquire the spectinomycin resistance conferred by the aadA gene on plasmid, but none of them managed to integrate transgenic DNA in their chromosome. Our results provide no indication that the theoretical gene transfer-enhancing properties of transplastomic plants cause horizontal gene transfer at rates above those found in other studies with nuclear transgenes.

  2. Chloride regulates leaf cell size and water relations in tobacco plants.

    PubMed

    Franco-Navarro, Juan D; Brumós, Javier; Rosales, Miguel A; Cubero-Font, Paloma; Talón, Manuel; Colmenero-Flores, José M

    2016-02-01

    Chloride (Cl(-)) is a micronutrient that accumulates to macronutrient levels since it is normally available in nature and actively taken up by higher plants. Besides a role as an unspecific cell osmoticum, no clear biological roles have been explicitly associated with Cl(-) when accumulated to macronutrient concentrations. To address this question, the glycophyte tobacco (Nicotiana tabacum L. var. Habana) has been treated with a basal nutrient solution supplemented with one of three salt combinations containing the same cationic balance: Cl(-)-based (CL), nitrate-based (N), and sulphate+phosphate-based (SP) treatments. Under non-saline conditions (up to 5 mM Cl(-)) and no water limitation, Cl(-) specifically stimulated higher leaf cell size and led to a moderate increase of plant fresh and dry biomass mainly due to higher shoot expansion. When applied in the 1-5 mM range, Cl(-) played specific roles in regulating leaf osmotic potential and turgor, allowing plants to improve leaf water balance parameters. In addition, Cl(-) also altered water relations at the whole-plant level through reduction of plant transpiration. This was a consequence of a lower stomatal conductance, which resulted in lower water loss and greater photosynthetic and integrated water-use efficiency. In contrast to Cl(-), these effects were not observed for essential anionic macronutrients such as nitrate, sulphate, and phosphate. We propose that the abundant uptake and accumulation of Cl(-) responds to adaptive functions improving water homeostasis in higher plants.

  3. Use of buckwheat seed protease inhibitor gene for improvement of tobacco and potato plant resistance to biotic stress.

    PubMed

    Khadeeva, N V; Kochieva, E Z; Tcherednitchenko, M Yu; Yakovleva, E Yu; Sydoruk, K V; Bogush, V G; Dunaevsky, Y E; Belozersky, M A

    2009-03-01

    The possibility to use agrobacterial transformation of leaf discs to produce resistance to bacterial infections in tobacco and potato plants by introduction of a single gene encoding the serine proteinase inhibitor BWI-1a (ISP) from buckwheat seeds is shown. All studied PCR-positive transgenic plants exhibited antibacterial activity in biotests. It was shown that the presence of just a single gene of serine proteinase inhibitor provides sufficient protection at least against two bacterial phytopathogens, Pseudomonas syringae pv. tomato and Clavibacter michiganensis sbsp. michiganensis. The biotest including tobacco plant infection by the white wings butterfly in the green house has also demonstrated the existence of protective effect in transgenic tobacco plants. Significant genotypic variations in the protection efficiency were found between members of different genera of the same family (potato and tobacco) as well as between different lines of the same species. Northern blot analysis of four transgenic potato lines and three tobacco lines transformed by a vector plasmid containing the ISP gene of serine proteinases BWI-1a from buckwheat seeds has shown the presence of the expected size mRNA transcript.

  4. Alkamides isolated from plants promote growth and alter root development in Arabidopsis.

    PubMed

    Ramírez-Chávez, Enrique; López-Bucio, José; Herrera-Estrella, Luis; Molina-Torres, Jorge

    2004-03-01

    To date, several classes of hormones have been described that influence plant development, including auxins, cytokinins, ethylene, and, more recently, brassinosteroids. However, it is known that many fungal and bacterial species produce substances that alter plant growth that, if naturally present in plants, might represent novel classes of plant growth regulators. Alkamides are metabolites widely distributed in plants with a broad range of biological activities. In this work, we investigated the effects of affinin, an alkamide naturally occurring in plants, and its derivates, N-isobutyl-2E-decenamide and N-isobutyl-decanamide, on plant growth and early root development in Arabidopsis. We found that treatments with affinin in the range of 10(-6) to 10(-4) m alter shoot and root biomass production. This effect correlated with alteration on primary root growth, lateral root formation, and root hair elongation. Low concentrations of affinin (7 x 10(-6)-2.8 x 10(-5) m) enhanced primary root growth and root hair elongation, whereas higher concentrations inhibited primary root growth that related with a reduction in cell proliferating activity and cell elongation. N-isobutyl-2E-decenamide and N-isobutyl-decanamide were found to stimulate root hair elongation at concentrations between 10(-8) to 10(-7) m. Although the effects of alkamides were similar to those produced by auxins on root growth and cell parameters, the ability of the root system to respond to affinin was found to be independent of auxin signaling. Our results suggest that alkamides may represent a new group of plant growth promoting substances with significant impact on root development and opens the possibility of using these compounds for improved plant production.

  5. Alkamides Isolated from Plants Promote Growth and Alter Root Development in Arabidopsis1

    PubMed Central

    Ramírez-Chávez, Enrique; López-Bucio, José; Herrera-Estrella, Luis; Molina-Torres, Jorge

    2004-01-01

    To date, several classes of hormones have been described that influence plant development, including auxins, cytokinins, ethylene, and, more recently, brassinosteroids. However, it is known that many fungal and bacterial species produce substances that alter plant growth that, if naturally present in plants, might represent novel classes of plant growth regulators. Alkamides are metabolites widely distributed in plants with a broad range of biological activities. In this work, we investigated the effects of affinin, an alkamide naturally occurring in plants, and its derivates, N-isobutyl-2E-decenamide and N-isobutyl-decanamide, on plant growth and early root development in Arabidopsis. We found that treatments with affinin in the range of 10-6 to 10-4 m alter shoot and root biomass production. This effect correlated with alteration on primary root growth, lateral root formation, and root hair elongation. Low concentrations of affinin (7 × 10-6–2.8 × 10-5 m) enhanced primary root growth and root hair elongation, whereas higher concentrations inhibited primary root growth that related with a reduction in cell proliferating activity and cell elongation. N-isobutyl-2E-decenamide and N-isobutyl-decanamide were found to stimulate root hair elongation at concentrations between 10-8 to 10-7 m. Although the effects of alkamides were similar to those produced by auxins on root growth and cell parameters, the ability of the root system to respond to affinin was found to be independent of auxin signaling. Our results suggest that alkamides may represent a new group of plant growth promoting substances with significant impact on root development and opens the possibility of using these compounds for improved plant production. PMID:14988477

  6. Development of tobacco ringspot virus-based vectors for foreign gene expression and virus-induced gene silencing in a variety of plants.

    PubMed

    Zhao, Fumei; Lim, Seungmo; Igori, Davaajargal; Yoo, Ran Hee; Kwon, Suk-Yoon; Moon, Jae Sun

    2016-05-01

    We report here the development of tobacco ringspot virus (TRSV)-based vectors for the transient expression of foreign genes and for the analysis of endogenous gene function in plants using virus-induced gene silencing. The jellyfish green fluorescent protein (GFP) gene was inserted between the TRSV movement protein (MP) and coat protein (CP) regions, resulting in high in-frame expression of the RNA2-encoded viral polyprotein. GFP was released from the polyprotein via an N-terminal homologous MP-CP cleavage site and a C-terminal foot-and-mouth disease virus (FMDV) 2 A catalytic peptide in Nicotiana benthamiana. The VIGS target gene was introduced in the sense and antisense orientations into a SnaBI site, which was created by mutating the sequence following the CP stop codon. VIGS of phytoene desaturase (PDS) in N. benthamiana, Arabidopsis ecotype Col-0, cucurbits and legumes led to obvious photo-bleaching phenotypes. A significant reduction in PDS mRNA levels in silenced plants was confirmed by semi-quantitative RT-PCR. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. 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

  8. Colocalization of barley lectin and sporamin in vacuoles of transgenic tobacco plants

    SciTech Connect

    Schroeder, M.R.; Borkhsenious, O.N.; Raikhel, N.V. ); Matsuoka, K.; Nakamura, K. )

    1993-02-01

    Various targeting motifs have been identified for plant proteins delivered to the vacuole. For barley (Hordeum vulgare) lectin, a typical Gramineae lectin and defense-related protein, the vacuolar information is contained in a carboxyl-terminal propeptide. In contrast, the vacuolar targeting information of sporamin, a storage protein from the tuberous roots of the sweet potato (Ipomoea batatas), is encoded in an amino-terminal propeptide. Both proteins were expressed simultaneously in transgenic tobacco plants to enable analysis of their posttranslational processing and subcellular localization by pulse-chase labeling and electron-microscopic immunocytochemical methods. The pulse-chase experiments demonstrated that processing and delivery to the vacuole are not impaired by the simultaneous expression of barley lectin and sporamin. Both proteins were targeted quantitatively to the vacuole, indication that the carboxyl-terminal and amino-terminal propeptided are equally recognized by the vacuolar protein-sorting machinery. Double-labeling experiments showed that barley lectin and sporamin accumulate in the same vacuole of transgenic tobacco (Nicotiana tabacum) leaf and root cells. 35 refs., 5 figs., 3 tabs.

  9. Contribution of AM inoculation and cattle manure to lead and cadmium phytoremediation by tobacco plants.

    PubMed

    Wang, Fa Yuan; Shi, Zhao Yong; Xu, Xiao Feng; Wang, Xu Gang; Li, You Jun

    2013-04-01

    Lead and cadmium are both highly toxic pollutants and pose potential risks to the environment and human health. Arbuscular mycorrhizal (AM) inoculation and organic amendments may make a potential contribution to phytoremediation of these toxic metals, but their effects remain unclear. We conducted a pot culture experiment to study the contribution of AM inoculation and/or cattle manure to phytoremediation of two soils artificially polluted with 0, 350, 500 and 1000 mg Pb per kg soil or 0, 1, 10, 100 mg Cd per kg soil using tobacco plants. Results showed that AM colonization was greatly reduced when exposed to more heavy metals especially Cd, whereas organic amendment alleviated metal stress and showed protective effects. In general, AM inoculation and cattle manure, singly or in combination, all significantly increased tobacco growth and Pb and Cd accumulation in shoots and roots, while decreased DTPA-extractable Pb and Cd concentrations in soil, and combination treatments (MN) produced the most pronounced positive effects. Improved plant P nutrition, higher soil pH and lower available metal concentrations contributed by AM inoculation and/or organic amendment may be the main strategies to alleviate metal toxicity and enhance phytoremediation efficiency. Our results indicate that AM fungi and organic manure play a synergistic positive role both in phytoextraction and phytostabilization of Cd and Pb.

  10. Heterodimerization of Arabidopsis calcium/proton exchangers contributes to regulation of guard cell dynamics and plant defense responses

    USDA-ARS?s Scientific Manuscript database

    "Arabidopsis thaliana" cation exchangers (CAX1 and CAX3) are closely related tonoplast-localized calcium/proton (Ca(2+)/H+) antiporters that contribute to cellular Ca(2+) homeostasis. CAX1 and CAX3 were previously shown to interact in yeast; however, the function of this complex in plants has remain...

  11. Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana

    PubMed Central

    Noutoshi, Yoshiteru; Ikeda, Mika; Saito, Tamio; Osada, Hiroyuki; Shirasu, Ken

    2012-01-01

    Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened two different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds – sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine – among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 μM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties. PMID:23118736

  12. Arabidopsis thaliana Glyoxalase 2-1 Is Required during Abiotic Stress but Is Not Essential under Normal Plant Growth

    PubMed Central

    Devanathan, Sriram; Erban, Alexander; Perez-Torres, Rodolfo; Kopka, Joachim; Makaroff, Christopher A.

    2014-01-01

    The glyoxalase pathway, which consists of the two enzymes, GLYOXALASE 1 (GLX 1) (E.C.: 4.4.1.5) and 2 (E.C.3.1.2.6), has a vital role in chemical detoxification. In Arabidopsis thaliana there are at least four different isoforms of glyoxalase 2, two of which, GLX2-1 and GLX2-4 have not been characterized in detail. Here, the functional role of Arabidopsis thaliana GLX2-1 is investigated. Glx2-1 loss-of-function mutants and plants that constitutively over-express GLX2-1 resemble wild-type plants under normal growth conditions. Insilico analysis of publicly available microarray datasets with ATTEDII, Mapman and Genevestigator indicate potential role(s) in stress response and acclimation. Results presented here demonstrate that GLX2-1 gene expression is up-regulated in wild type Arabidopsis thaliana by salt and anoxia stress, and by excess L-Threonine. Additionally, a mutation in GLX2-1 inhibits growth and survival during abiotic stresses. Metabolic profiling studies show alterations in the levels of sugars and amino acids during threonine stress in the plants. Elevated levels of polyamines, which are known stress markers, are also observed. Overall our results suggest that Arabidopsis thaliana GLX2-1 is not essential during normal plant life, but is required during specific stress conditions. PMID:24760003

  13. Arabidopsis thaliana is a susceptible host plant for the holoparasite Cuscuta spec.

    PubMed

    Birschwilks, Mandy; Sauer, Norbert; Scheel, Dierk; Neumann, Stefanie

    2007-10-01

    Arabidopsis thaliana and Cuscuta spec. represent a compatible host-parasite combination. Cuscuta produces a haustorium that penetrates the host tissue. In early stages of development the searching hyphae on the tip of the haustorial cone are connected to the host tissue by interspecific plasmodesmata. Ten days after infection, translocation of the fluorescent dyes, Texas Red (TR) and 5,6-carboxyfluorescein (CF), demonstrates the existence of a continuous connection between xylem and phloem of the host and parasite. Cuscuta becomes the dominant sink in this host-parasite system. Transgenic Arabidopsis plants expressing genes encoding the green fluorescent protein (GFP; 27 kDa) or a GFP-ubiquitin fusion (36 kDa), respectively, under the companion cell (CC)-specific AtSUC2 promoter were used to monitor the transfer of these proteins from the host sieve elements to those of Cuscuta. Although GFP is transferred unimpedly to the parasite, the GFP-ubiquitin fusion could not be detected in Cuscuta. A translocation of the GFP-ubiquitin fusion protein was found to be restricted to the phloem of the host, although a functional symplastic pathway exists between the host and parasite, as demonstrated by the transport of CF. These results indicate a peripheral size exclusion limit (SEL) between 27 and 36 kDa for the symplastic connections between host and Cuscuta sieve elements. Forty-six accessions of A. thaliana covering the entire range of its genetic diversity, as well as Arabidopsis halleri, were found to be susceptible towards Cuscuta reflexa.

  14. Arabidopsis purple acid phosphatase 10 is a component of plant adaptive mechanism to phosphate limitation.

    PubMed

    Wang, Liangsheng; Liu, Dong

    2012-03-01

    When grown with inadequate quantities of inorganic phosphate (Pi), plants synthesize and secret acid phosphatases into the rhizosphere. These secreted acid phosphatases are thought to release the Pi group from organophosphates present in the surrounding environment and to thereby increase Pi availability to plants. So far, however, the genetic evidence to support this hypothesis is still lacking. Previously, we showed that overexpression of Arabidopsis purple acid phosphatase 10 (AtPAP10) improved the growth of plants on Pi-deficient medium (P⁻ medium) supplemented with the organophosphate compound ADP; in contrast, the growth of atpap10 mutant lines was reduced on the same medium. In the current research, we determined the growth performance of these lines on P⁻ medium supplemented with four other organophosphates. The results showed that AtPAP10 could utilize rhizosphere organophosphates other than ADP for plant growth but with different utilization efficiencies. This work provides further genetic evidence that AtPAP10 phosphatase is a component of plant adaptive mechanism to Pi limitation.

  15. Overexpression of PSP1 enhances growth of transgenic Arabidopsis plants under ambient air conditions.

    PubMed

    Han, Xiaofang; Peng, Keli; Wu, Haixia; Song, Shanshan; Zhu, Yerong; Bai, Yanling; Wang, Yong

    2017-07-01

    The importance of the phosphorylated pathway (PPSB) of L-serine (Ser) biosynthesis in plant growth and development has been demonstrated, but its specific role in leaves and interaction with photorespiration, the main leaf Ser biosynthetic pathway at daytime, are still unclear. To investigate whether changes in biosynthesis of Ser by the PPSB in leaves could have an impact on photorespiration and plant growth, we overexpressed PSP1, the last enzyme of this pathway, under control of the Cauliflower Mosaic Virus 35S promoter in Arabidopsis thaliana. Overexpressor plants grown in normal air displayed larger rosette diameter and leaf area as well as higher fresh and dry weight than the wild type. By contrast, no statistically significant differences to the wild type were observed when the overexpressor seedlings were transferred to elevated CO2, indicating a relationship between PSP1 overexpression and photorespiration. Additionally, the transgenic plants displayed higher photorespiration, an increase in CO2 net-uptake and stronger expression in the light of genes encoding enzymes involved in photorespiration. We further demonstrated that expression of many genes involved in nitrogen assimilation was also promoted in leaves of transgenic plants and that leaf nitrate reductase activity increased in the light, too, although not in the dark. Our results suggest a close correlation between the function of PPSB and photorespiration, and also nitrogen metabolism in leaves.

  16. Arsenic and mercury tolerance and cadmium sensitivity in Arabidopsis plants expressing bacterial gamma-glutamylcysteine synthetase.

    PubMed

    Li, Yujing; Dhankher, Om Parkash; Carreira, Laura; Balish, Rebecca S; Meagher, Richard B

    2005-06-01

    Cysteine sulfhydryl-rich peptide thiols are believed to play important roles in the detoxification of many heavy metals and metalloids such as arsenic, mercury, and cadmium in plants. The gamma-glutamylcysteine synthetase (gamma-ECS) catalyzes the synthesis of the dipeptidethiol gamma-glu-cys (gamma-EC), the first step in the biosynthesis of phytochelatins (PCs). Arabidopsis thaliana, engineered to express the bacterial gamma-ECS gene under control of a strong constitutive actin regulatory sequence (A2), expressed gamma-ECS at levels approaching 0.1% of total protein. In response to arsenic, mercury, and cadmium stresses, the levels of gamma-EC and its derivatives, glutathione (GSH) and PCs, were increased in the A2::ECS transgenic plants to three- to 20-fold higher concentrations than the increases that occurred in wild-type (WT). Compared to cadmium and mercury treatments, arsenic treatment most significantly increased levels of gamma-EC and PCs in both the A2::ECS transgenic and WT plants. The A2::ECS transgenic plants were highly resistant to arsenic and weakly resistant to mercury. Although exposure to cadmium produced three- to fivefold increases in levels of gamma-EC-related peptides in the A2::ECS lines, these plants were significantly more sensitive to Cd(II) than WT and trace levels of Cd(II) blocked resistance to arsenic and mercury. A few possible mechanisms for gamma-ECS-enhanced arsenic and mercury resistance and cadmium hypersensitivity are discussed.

  17. Overexpression of cotton PYL genes in Arabidopsis enhances the transgenic plant tolerance to drought stress.

    PubMed

    Chen, Yun; Feng, Li; Wei, Ning; Liu, Zhi-Hao; Hu, Shan; Li, Xue-Bao

    2017-03-30

    PYR/PYL/RCAR proteins are putative abscisic acid (ABA) receptors that play important roles in plant responses to biotic and abiotic stresses. In this study, 27 predicted PYL proteins were identified in cotton (Gossypium hirsutum). Sequence analysis showed they are conserved in structures. Phylogenetic analysis showed that cotton PYL family could be categorized into three groups. Yeast two-hybrid assay revealed that the GhPYL proteins selectively interacted with some GhPP2C proteins. Quantitative RT-PCR analysis indicated that the most of nine GhPYL genes were down-regulated, while the other three were up-regulated in cotton under drought stress. Overexpression of GhPYL10/12/26 in Arabidopsis conferred the transgenic plants increased ABA sensitivity during seed germination and early seedling growth. On the contrary, the transgenic seedlings displayed better growth status and longer primary roots under normal conditions and mannitol stress, compared with wild type. Furthermore, the transgenic plants showed the enhanced drought tolerance, relative to wild type, when they were suffered from drought stress. Expression of some stress-related genes in transgenic plants was significant higher than that in wild type under osmotic stress. Thus, our data suggested that these cotton PYL genes may be involved in plant response and defense to drought/osmotic stress.

  18. Plant proximity perception dynamically modulates hormone levels and sensitivity in Arabidopsis

    PubMed Central

    Bou-Torrent, Jordi; Galstyan, Anahit; Gallemí, Marçal; Cifuentes-Esquivel, Nicolás; Molina-Contreras, Maria José; Salla-Martret, Mercè; Jikumaru, Yusuke; Yamaguchi, Shinjiro; Kamiya, Yuji; Martínez-García, Jaime F.

    2014-01-01

    The shade avoidance syndrome (SAS) refers to a set of plant responses initiated after perception by the phytochromes of light enriched in far-red colour reflected from or filtered by neighbouring plants. These varied responses are aimed at anticipating eventual shading from potential competitor vegetation. In Arabidopsis thaliana, the most obvious SAS response at the seedling stage is the increase in hypocotyl elongation. Here, we describe how plant proximity perception rapidly and temporally alters the levels of not only auxins but also active brassinosteroids and gibberellins. At the same time, shade alters the seedling sensitivity to hormones. Plant proximity perception also involves dramatic changes in gene expression that rapidly result in a new balance between positive and negative factors in a network of interacting basic helix–loop–helix proteins, such as HFR1, PAR1, and BIM and BEE factors. Here, it was shown that several of these factors act as auxin- and BR-responsiveness modulators, which ultimately control the intensity or degree of hypocotyl elongation. It was deduced that, as a consequence of the plant proximity-dependent new, dynamic, and local balance between hormone synthesis and sensitivity (mechanistically resulting from a restructured network of SAS regulators), SAS responses are unleashed and hypocotyls elongate. PMID:24609653

  19. Cadmium localization and quantification in the plant Arabidopsis thaliana using micro-PIXE

    NASA Astrophysics Data System (ADS)

    Ager, F. J.; Ynsa, M. D.; Domínguez-Solís, J. R.; Gotor, C.; Respaldiza, M. A.; Romero, L. C.

    2002-04-01

    Remediation of metal-contaminated soils and waters poses a challenging problem due to its implications in the environment and the human health. The use of metal-accumulating plants to remove toxic metals, including Cd, from soil and aqueous streams has been proposed as a possible solution to this problem. The process of using plants for environmental restoration is termed phytoremediation. Cd is a particularly favourable target metal for this technology because it is readily transported and accumulated in the shoots of several plant species. This paper investigates the sites of metal localization within Arabidopsis thaliana leaves, when plants are grown in a cadmium-rich environment, by making use of nuclear microscopy techniques. Micro-PIXE, RBS and SEM analyses were performed on the scanning proton microprobe at the CNA in Seville (Spain), showing that cadmium is sequestered within the trichomes on the leaf surface. Additionally, regular PIXE analyses were performed on samples prepared by an acid digestion method in order to assess the metal accumulation of such plants.

  20. Brassinosteroids stimulate plant tropisms through modulation of polar auxin transport in Brassica and Arabidopsis.

    PubMed

    Li, Li; Xu, Jian; Xu, Zhi-Hong; Xue, Hong-Wei

    2005-10-01

    Brassinosteroids (BRs) are important plant growth regulators in multiple developmental processes. Previous studies have indicated that BR treatment enhanced auxin-related responses, but the underlying mechanisms remain unknown. Using (14)C-labeled indole-3-acetic acid and Arabidopsis thaliana plants harboring an auxin-responsive reporter construct, we show that the BR brassinolide (BL) stimulates polar auxin transport capacities and modifies the distribution of endogenous auxin. In plants treated with BL or defective in BR biosynthesis or signaling, the transcription of PIN genes, which facilitate functional auxin transport in plants, was differentially regulated. In addition, BL enhanced plant tropistic responses by promoting the accumulation of the PIN2 protein from the root tip to the elongation zone and stimulating the expression and dispersed localization of ROP2 during tropistic responses. Constitutive overexpression of ROP2 results in enhanced polar accumulation of PIN2 protein in the root elongation region and increased gravitropism, which is significantly affected by latrunculin B, an inhibitor of F-actin assembly. The ROP2 dominant negative mutants (35S-ROP2-DA/DN) show delayed tropistic responses, and this delay cannot be reversed by BL addition, strongly supporting the idea that ROP2 modulates the functional localization of PIN2 through regulation of the assembly/reassembly of F-actins, thereby mediating the BR effects on polar auxin transport and tropistic responses.

  1. Plant proximity perception dynamically modulates hormone levels and sensitivity in Arabidopsis.

    PubMed

    Bou-Torrent, Jordi; Galstyan, Anahit; Gallemí, Marçal; Cifuentes-Esquivel, Nicolás; Molina-Contreras, Maria José; Salla-Martret, Mercè; Jikumaru, Yusuke; Yamaguchi, Shinjiro; Kamiya, Yuji; Martínez-García, Jaime F

    2014-06-01

    The shade avoidance syndrome (SAS) refers to a set of plant responses initiated after perception by the phytochromes of light enriched in far-red colour reflected from or filtered by neighbouring plants. These varied responses are aimed at anticipating eventual shading from potential competitor vegetation. In Arabidopsis thaliana, the most obvious SAS response at the seedling stage is the increase in hypocotyl elongation. Here, we describe how plant proximity perception rapidly and temporally alters the levels of not only auxins but also active brassinosteroids and gibberellins. At the same time, shade alters the seedling sensitivity to hormones. Plant proximity perception also involves dramatic changes in gene expression that rapidly result in a new balance between positive and negative factors in a network of interacting basic helix-loop-helix proteins, such as HFR1, PAR1, and BIM and BEE factors. Here, it was shown that several of these factors act as auxin- and BR-responsiveness modulators, which ultimately control the intensity or degree of hypocotyl elongation. It was deduced that, as a consequence of the plant proximity-dependent new, dynamic, and local balance between hormone synthesis and sensitivity (mechanistically resulting from a restructured network of SAS regulators), SAS responses are unleashed and hypocotyls elongate.

  2. [Morphological analysis of transgenic tobacco plants expressing the PnEXPA3 gene of black poplar (Populus nigra)].

    PubMed

    Kuluev, B R; Safiullina, M G; Kniazev, A V; Chemeris, A V

    2013-01-01

    Transgenic tobacco plants overexpressing the PnEXPA3 gene of black poplar (Populus nigra), which encodes alpha-expansin, were obtained. The transgenic plants were characterized by increased size of epidermic and mesophyll cells of leaves. However, the size of leaves remained normal. Overexpression of the PnEXPA3 gene provided stimulatory effect only on the stem length. Other morphological traits of the transgenic plants remained unchanged.

  3. Enhancement of naphthalene tolerance in transgenic Arabidopsis plants overexpressing the ferredoxin-like protein (ADI1) from rice.

    PubMed

    Fu, Xiao-Yan; Zhu, Bo; Han, Hong-Juan; Zhao, Wei; Tian, Yong-Sheng; Peng, Ri-He; Yao, Quan-Hong

    2016-01-01

    The ADI1 Arabidopsis plants enhanced tolerance and degradation efficiency to naphthalene and had great potential for phytoremediation of naphthalene in the plant material before composting or harvesting and removal. Naphthalene is a global environmental concern, because this substance is assumed to contribute considerably to human cancer risk. Cleaning up naphthalene contamination in the environment is crucial. Phytoremediation is an efficient technology to clean up contaminants. However, no gene that can efficiently degrade exogenous recalcitrant naphthalene in plants has yet been discovered. Ferredoxin (Fd) is a key player of biological electron transfer reaction in the PAH degradation process. The biochemical pathway for bacterial degradation of naphthalene has been well investigated. In this study, a rice gene, ADI1, which codes for a putative photosynthetic-type Fd, has been transformed into Arabidopsis thaliana. The transgenic Arabidopsis plants enhanced tolerance and degradation efficiency of naphthalene. Compared with wild-type plants, transgenic plants assimilated naphthalene from the culture media faster and removed more of this substance. When taken together, our findings suggest that breeding plants with overexpressed ADI1 gene is an effective strategy to degrade naphthalene in the environment.

  4. Arabidopsis ECERIFERUM9 involvement in cuticle formation and maintenance of plant water status.

    PubMed

    Lü, Shiyou; Zhao, Huayan; Des Marais, David L; Parsons, Eugene P; Wen, Xiaoxue; Xu, Xiaojing; Bangarusamy, Dhinoth K; Wang, Guangchao; Rowland, Owen; Juenger, Thomas; Bressan, Ray A; Jenks, Matthew A

    2012-07-01

    Mutation of the ECERIFERUM9 (CER9) gene in Arabidopsis (Arabidopsis thaliana) causes elevated amounts of 18-carbon-length cutin monomers and a dramatic shift in the cuticular wax profile (especially on leaves) toward the very-long-chain free fatty acids tetracosanoic acid (C₂₄) and hexacosanoic acid (C₂₆). Relative to the wild type, cer9 mutants exhibit elevated cuticle membrane thickness over epidermal cells and cuticular ledges with increased occlusion of the stomatal pore. The cuticular phenotypes of cer9 are associated with delayed onset of wilting in plants experiencing water deficit, lower transpiration rates, and improved water use efficiency measured as carbon isotope discrimination. The CER9 protein thus encodes a novel determinant of plant drought tolerance-associated traits, one whose deficiency elevates cutin synthesis, redistributes wax composition, and suppresses transpiration. Map-based cloning identified CER9, and sequence analysis predicted that it encodes an E3 ubiquitin ligase homologous to yeast Doa10 (previously shown to target endoplasmic reticulum proteins for proteasomal degradation). To further elucidate CER9 function, the impact of CER9 deficiency on interactions with other genes was examined using double mutant and transcriptome analyses. For both wax and cutin, cer9 showed mostly additive effects with cer6, long-chain acyl-CoA synthetase1 (lacs1), and lacs2 and revealed its role in early steps of both wax and cutin synthetic pathways. Transcriptome analysis revealed that the cer9 mutation affected diverse cellular processes, with primary impact on genes associated with diverse stress responses. The discovery of CER9 lays new groundwork for developing novel cuticle-based strategies for improving the drought tolerance and water use efficiency of crop plants.

  5. Low-temperature-induced transcription factors in grapevine enhance cold tolerance in transgenic Arabidopsis plants.

    PubMed

    Takuhara, Yuki; Kobayashi, Masayuki; Suzuki, Shunji

    2011-06-15

    We report the characterization of low-temperature-induced transcription factors in grapevine (Vitis vinifera). Four transcription factors were identified in low-temperature-treated grapevine. The expression of V. vinifera C-repeat-binding factors, VvCBF2, VvCBF4, and VvCBFL, and V. vinifera B-box-type zinc finger protein, VvZFPL, was immediately induced and upregulated in leaves by the low-temperature treatment. Similar induction of the gene expression was observed in low-temperature-treated stems and flowers, although VvZFPL was constitutively expressed in flowers. Tendrils expressed all the four genes constitutively. In berry skin, VvCBF2 and VvCBFL were induced by the low-temperature treatment before the onset of véraison, while only VvCBF2 was induced under the low-temperature condition after the onset of véraison. The overexpression of VvCBF2 and VvZFPL in Arabidopsis plants led to longer hypocotyls than the control plants. The rosette leaves of these plants were smaller and had lower chlorophyll contents than those of the control plants, resulting in a pale green color. Finally, the VvCBF2- and VvZFPL-overexpressing plants revealed growth retardation. These results suggest that VvCBF2 and VvZFPL may affect photomorphogenesis and growth in grapevine. Meanwhile, no morphological changes were detected in the VvCBF4- and VvCBFL-overexpressing plants. The cold tolerance test demonstrated that all of the overexpressing plants remained viable and noticeably healthy compared with the control plants even after exposure to severe cold treatment, suggesting that VvCBF2, VvCBF4, VvCBFL, or VvZFPL may enhance cold tolerance in grapevine.

  6. Serendipitous solution to the problem of culturing Arabidopsis plants in sealed containers for spaceflights of long duration

    NASA Technical Reports Server (NTRS)

    Brown, A. H.; Odowd, P.; Loercher, L.; Kuniewicz, R.; Dahl, A. O.

    1979-01-01

    The Arabidopsis thaliana plant species is tested to determine how a higher plant will develop from seed to maturity when deprived of all gravitational information that it might use to control its growth. Experimental results show that Arabidopsis seedlings can develop to maturity by means of a light-dependent but CO2-independent metabolism that feeds on organic compounds derived from the culture medium. This process is identified as photoassimilation. The ability of a higher plant to nourish itself by photoassimilation and thereby to survive in a heremetically sealed chamber of small dimensions is more than a biochemical curiosity. It allows the botanical investigator to design a culture system convenient for space-flight applications, which ensures isolation of each test plant from the gaseous environment of the spacecraft.

  7. Expression of wheat expansin driven by the RD29 promoter in tobacco confers water-stress tolerance without impacting growth and development.

    PubMed

    Li, Feng; Han, Yangyang; Feng, Yanan; Xing, Shichao; Zhao, Meirong; Chen, Yanhui; Wang, Wei

    2013-02-10

    Expansins are the key regulators of cell wall extension during plant growth. Previously, we produced transgenic tobacco plants with increased tolerance to water stress by overexpressing the wheat expansin gene TaEXPB23 driven by the constitutive 35S cauliflower mosaic virus (CaMV) promoter. However, the growth and development of 35S::TaEXPB23 transgenic tobacco plants were altered under normal growth conditions, with a faster growth rate at the seedling stage, earlier flowering and maturation, and a shorter plant height compared to WT. In the current study, we determined that cellular characteristics and carbohydrate metabolism were altered in 35S::TaEXPB23 transgenic tobacco plants. We also generated transgenic Arabidopsis plants using the same vector. The transgenic Arabidopsis plants had the same phenotype as the transgenic tobacco plants, which may have resulted from the altered expression of several flowering-related genes. We then produced TaEXPB23 transgenic tobacco plants using the stress-inducible RD29A promoter. The use of this promoter reduced the negative effects of TaEXPB23 on plant growth and development. The RD29A::TaEXPB23 transgenic tobacco plants had greater tolerance to water stress than WT, as determined by examining physiological and biochemical parameters. Therefore, the use of stress-inducible promoters, such as RD29A, may minimize the negative effects of constitutive transgene expression and improve the water-stress tolerance of plants.

  8. Pathogen Phytosensing: Plants to Report Plant Pathogens.

    PubMed

    Mazarei, Mitra; Teplova, Irina; Hajimorad, M Reza; Stewart, C Neal

    2008-04-14

    Real-time systems that provide evidence of pathogen contamination in crops can be an important new line of early defense in agricultural centers. Plants possess defense mechanisms to protect against pathogen attack. Inducible plant defense is controlled by signal transduction pathways, inducible promoters and cis-regulatory elements corresponding to key genes involved in defense, and pathogen-specific responses. Identified inducible promoters and cis-acting elements could be utilized in plant sentinels, or 'phytosensors', by fusing these to reporter genes to produce plants with altered phenotypes in response to the presence of pathogens. Here, we have employed cis-acting elements from promoter regions of pathogen inducible genes as well as those responsive to the plant defense signal molecules salicylic acid, jasmonic acid, and ethylene. Synthetic promoters were constructed by combining various regulatory elements supplemented with the enhancer elements from the Cauliflower mosaic virus (CaMV) 35S promoter to increase basal level of the GUS expression. The inducibility of each synthetic promoter was first assessed in transient expression assays using Arabidopsis thaliana protoplasts and then examined for efficacy in stably transgenic Arabidopsis and tobacco plants. Histochemical and fluorometric GUS expression analyses showed that both transgenic Arabidopsis and tobacco plants responded to elicitor and phytohormone treatments with increased GUS expression when compared to untreated plants. Pathogen-inducible phytosensor studies were initiated by analyzing the sensitivity of the synthetic promoters against virus infection. Transgenic tobacco plants infected with Alfalfa mosaic virus showed an increase in GUS expression when compared to mock-inoculated control plants, whereas Tobacco mosaic virus infection caused no changes in GUS expression. Further research, using these transgenic plants against a range of different pathogens with the regulation of detectable

  9. 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

  10. 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.

  11. Osmotic stress responses and plant growth controlled by potassium transporters in Arabidopsis.

    PubMed

    Osakabe, Yuriko; Arinaga, Naoko; Umezawa, Taishi; Katsura, Shogo; Nagamachi, Keita; Tanaka, Hidenori; Ohiraki, Haruka; Yamada, Kohji; Seo, So-Uk; Abo, Mitsuru; Yoshimura, Etsuro; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2013-02-01

    Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K(+) uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K(+) channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using (86)radioactive rubidium ion ((86)Rb(+)) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses.

  12. Osmotic Stress Responses and Plant Growth Controlled by Potassium Transporters in Arabidopsis[C][W

    PubMed Central

    Osakabe, Yuriko; Arinaga, Naoko; Umezawa, Taishi; Katsura, Shogo; Nagamachi, Keita; Tanaka, Hidenori; Ohiraki, Haruka; Yamada, Kohji; Seo, So-Uk; Abo, Mitsuru; Yoshimura, Etsuro; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2013-01-01

    Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K+ uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K+ channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using 86radioactive rubidium ion (86Rb+) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses. PMID:23396830

  13. Immunodiagnostic Properties of Wucheraria bancrofti SXP-1, a Potential Filarial Diagnostic Candidate Expressed in Tobacco Plant, Nicotiana tabacum.

    PubMed

    Ganapathy, Mathangi; Chakravarthi, M; Charles, S Jason; Harunipriya, P; Jaiganesh, S; Subramonian, N; Kaliraj, P

    2015-08-01

    Transgenic tobacco plants were developed expressing WbSXP-1, a diagnostic antigen isolated from the cDNA library of L3 stage larvae of Wucheraria bancrofti. This antigen produced by recombinant Escherichia coli has been demonstrated by to be successful as potential diagnostic candidate against lymphatic filariasis. A rapid format simple and qualitative flow through immune-filtration diagnostic kit has been developed for the identification of IgG antibodies to the recombinant WbSXP-1 and is being marketed by M/S Span Diagnostics Ltd in India and Africa. Here, we present the results of experiments on the transformation and expression of the same filarial antigen, WbSXP-1, in tobacco plant, Nicotiana tabacum, to produce plant-based diagnostic antigen. It was possible to successfully transform the tobacco plant with WbSXP-1, the integration of the parasite-specific gene in plants was confirmed by PCR amplification and the expression of the filarial protein by Western blotting. The immunoreactivity of the plant-produced WbSXP-1 was assessed based on its reaction with the monoclonal antibodies developed against the E. coli-produced protein. Immunological screening using clinical sera from patients indicates that the plant-produced protein is comparable to E. coli-produced diagnostic antigen. The result demonstrated that plants can be used as suitable expression systems for the production of diagnostic proteins against lymphatic filariasis, a neglected tropical infectious disease which has a negative impact on socioeconomic development. This is the first report of the integration, expression and efficacy of a diagnostic candidate of lymphatic filariasis in plants.Key MessageTransgenic tobacco plants with WbSXP-1, a filarial diagnostic candidate, were developed. The plant-produced protein showed immunoreactivity on par with the E. coli product.

  14. Identification of a Retroelement from the Resurrection Plant Boea hygrometrica That Confers Osmotic and Alkaline Tolerance in Arabidopsis thaliana

    PubMed Central

    Shen, Chun-Ying; Xu, Guang-Hui; Chen, Shi-Xuan; Song, Li-Zhen; Li, Mei-Jing; Wang, Li-Li; Zhu, Yan; Lv, Wei-Tao; Gong, Zhi-Zhong; Liu, Chun-Ming; Deng, Xin

    2014-01-01

    Functional genomic elements, including transposable elements, small RNAs and non-coding RNAs, are involved in regulation of gene expression in response to plant stress. To identify genomic elements that regulate dehydration and alkaline tolerance in Boea hygrometrica, a resurrection plant that inhabits drought and alkaline Karst areas, a genomic DNA library from B. hygrometrica was constructed and subsequently transformed into Arabidopsis using binary bacterial artificial chromosome (BIBAC) vectors. Transgenic lines were screened under osmotic and alkaline conditions, leading to the identification of Clone L1-4 that conferred osmotic and alkaline tolerance. Sequence analyses revealed that L1-4 contained a 49-kb retroelement fragment from B. hygrometrica, of which only a truncated sequence was present in L1-4 transgenic Arabidopsis plants. Additional subcloning revealed that activity resided in a 2-kb sequence, designated Osmotic and Alkaline Resistance 1 (OAR1). In addition, transgenic Arabidopsis lines carrying an OAR1-homologue also showed similar stress tolerance phenotypes. Physiological and molecular analyses demonstrated that OAR1-transgenic plants exhibited improved photochemical efficiency and membrane integrity and biomarker gene expression under both osmotic and alkaline stresses. Short transcripts that originated from OAR1 were increased under stress conditions in both B. hygrometrica and Arabidopsis carrying OAR1. The relative copy number of OAR1 was stable in transgenic Arabidopsis under stress but increased in B. hygrometrica. Taken together, our results indicated a potential role of OAR1 element in plant tolerance to osmotic and alkaline stresses, and verified the feasibility of the BIBAC transformation technique to identify functional genomic elements from physiological model species. PMID:24851859

  15. Identification of a retroelement from the resurrection plant Boea hygrometrica that confers osmotic and alkaline tolerance in Arabidopsis thaliana.

    PubMed

    Zhao, Yan; Xu, Tao; Shen, Chun-Ying; Xu, Guang-Hui; Chen, Shi-Xuan; Song, Li-Zhen; Li, Mei-Jing; Wang, Li-Li; Zhu, Yan; Lv, Wei-Tao; Gong, Zhi-Zhong; Liu, Chun-Ming; Deng, Xin

    2014-01-01

    Functional genomic elements, including transposable elements, small RNAs and non-coding RNAs, are involved in regulation of gene expression in response to plant stress. To identify genomic elements that regulate dehydration and alkaline tolerance in Boea hygrometrica, a resurrection plant that inhabits drought and alkaline Karst areas, a genomic DNA library from B. hygrometrica was constructed and subsequently transformed into Arabidopsis using binary bacterial artificial chromosome (BIBAC) vectors. Transgenic lines were screened under osmotic and alkaline conditions, leading to the identification of Clone L1-4 that conferred osmotic and alkaline tolerance. Sequence analyses revealed that L1-4 contained a 49-kb retroelement fragment from B. hygrometrica, of which only a truncated sequence was present in L1-4 transgenic Arabidopsis plants. Additional subcloning revealed that activity resided in a 2-kb sequence, designated Osmotic and Alkaline Resistance 1 (OAR1). In addition, transgenic Arabidopsis lines carrying an OAR1-homologue also showed similar stress tolerance phenotypes. Physiological and molecular analyses demonstrated that OAR1-transgenic plants exhibited improved photochemical efficiency and membrane integrity and biomarker gene expression under both osmotic and alkaline stresses. Short transcripts that originated from OAR1 were increased under stress conditions in both B. hygrometrica and Arabidopsis carrying OAR1. The relative copy number of OAR1 was stable in transgenic Arabidopsis under stress but increased in B. hygrometrica. Taken together, our results indicated a potential role of OAR1 element in plant tolerance to osmotic and alkaline stresses, and verified the feasibility of the BIBAC transformation technique to identify functional genomic elements from physiological model species.

  16. Effects of root-zone acidity on utilization of nitrate and ammonium in tobacco plants

    NASA Technical Reports Server (NTRS)

    Henry, L. T.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1989-01-01

    Tobacco (Nicotiana tabacum L., cv. 'Coker 319') plants were grown for 28 days in flowing nutrient culture containing either 1.0 mM NO3- or 1.0 mM NH4+ as the nitrogen source in a complete nutrient solution. Acidities of the solutions were controlled at pH 6.0 or 4.0 for each nitrogen source. Plants were sampled at intervals of 6 to 8 days for determination of dry matter and nitrogen accumulation. Specific rates of NO3- or NH4+ uptake (rate of uptake per unit root mass) were calculated from these data. Net photosynthetic rates per unit leaf area were measured on attached leaves by infrared gas analysis. When NO3- [correction of NO-] was the sole nitrogen source, root growth and nitrogen uptake rate were unaffected by pH of the solution, and photosynthetic activity of leaves and accumulation of dry matter and nitrogen in the whole plant were similar. When NH4+ was the nitrogen source, photosynthetic rate of leaves and accumulation of dry matter and nitrogen in the whole plant were not statistically different from NO3(-) -fed plants when acidity of the solution was controlled at pH 6.0. When acidity for NH4(+) -fed plants was increased to pH 4.0, however, specific rate of NH4+ uptake decreased by about 50% within the first 6 days of treatment. The effect of acidity on root function was associated with a decreased rate of accumulation of nitrogen in shoots that was accompanied by a rapid cessation of leaf development between days 6 and 13. The decline in leaf growth rate of NH4(+) -fed plants at pH 4.0 was followed by reductions in photosynthetic rate per unit leaf area. These responses of NH4(+) -fed plants to increased root-zone acidity are characteristic of the sequence of responses that occur during onset of nitrogen stress.

  17. Effects of root-zone acidity on utilization of nitrate and ammonium in tobacco plants

    NASA Technical Reports Server (NTRS)

    Henry, L. T.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1989-01-01

    Tobacco (Nicotiana tabacum L., cv. 'Coker 319') plants were grown for 28 days in flowing nutrient culture containing either 1.0 mM NO3- or 1.0 mM NH4+ as the nitrogen source in a complete nutrient solution. Acidities of the solutions were controlled at pH 6.0 or 4.0 for each nitrogen source. Plants were sampled at intervals of 6 to 8 days for determination of dry matter and nitrogen accumulation. Specific rates of NO3- or NH4+ uptake (rate of uptake per unit root mass) were calculated from these data. Net photosynthetic rates per unit leaf area were measured on attached leaves by infrared gas analysis. When NO3- [correction of NO-] was the sole nitrogen source, root growth and nitrogen uptake rate were unaffected by pH of the solution, and photosynthetic activity of leaves and accumulation of dry matter and nitrogen in the whole plant were similar. When NH4+ was the nitrogen source, photosynthetic rate of leaves and accumulation of dry matter and nitrogen in the whole plant were not statistically different from NO3(-) -fed plants when acidity of the solution was controlled at pH 6.0. When acidity for NH4(+) -fed plants was increased to pH 4.0, however, specific rate of NH4+ uptake decreased by about 50% within the first 6 days of treatment. The effect of acidity on root function was associated with a decreased rate of accumulation of nitrogen in shoots that was accompanied by a rapid cessation of leaf development between days 6 and 13. The decline in leaf growth rate of NH4(+) -fed plants at pH 4.0 was followed by reductions in photosynthetic rate per unit leaf area. These responses of NH4(+) -fed plants to increased root-zone acidity are characteristic of the sequence of responses that occur during onset of nitrogen stress.

  18. [Effects of soil, climate, and their interaction on some neutral volatile aroma components in flue-cured tobacco leaves from high quality tobacco planting regions of Hunan Province].

    PubMed

    Deng, Xiao-Hua; Xie, Peng-Fei; Peng, Xin-Hui; Yi, Jian-Hua; Zhou, Ji-Heng; Zhou, Qing-Ming; Pu, Wen-Xuan; Dai, Yuan-Gang

    2010-08-01

    A pot experiment with the soils from Yongzhou, Liuyang, and Sangzhi, the high-quality tobacco planting regions of Hunan Province, was conducted to study the effects of climate, soil, and their interaction on some neutral volatile aroma components in flue-cured tobacco leaves. The contents of test neutral volatile aroma components in the flue-cured tobacco leaves were of medium variation, and the variation intensity was decreased in the order of dihydroactinolide, damascenone, furfural, total megastigmatrienone, and beta-ionone. Climate, soil, and their interaction affected the neutral volatile aroma components in different degrees. The furfural content was most affected by climate, the damascenone content was most affected by climate and by soil, the total megastigmatrienone and beta-ionone contents were most affected by the interaction of soil and climate, while the dihydroactinolide content was less affected by soil, climate, and their interaction. The contribution of climate, soil, and their interaction to the contents of the five aroma components was 40.82%, 20.67%, and 38.51%, respectively. During different growth periods of tobacco, different climate factors had different effects on the neutral volatile aroma components. The rainfall, cloudiness, and mean air temperature at rooting stage, the diurnal temperature amplitude, sunshine time, and evaporation at vigorous growth stage, and the rainfall, evaporation, and mean air temperature at maturing stage were the top three climate factors affecting the contents of the neutral volatile aroma components in flue-tobacco leaves. For the soil factors, the available potassium, available phosphorus, and pH were the top three factors affecting the contents of the five components.

  19. The major leaf ferredoxin Fd2 regulates plant innate immunity in Arabidopsis.

    PubMed

    Wang, Mo; Rui, Lu; Yan, Haojie; Shi, Hua; Zhao, Wanying; Lin, Jinshan Ella; Zhang, Kai; Blakeslee, Joshua J; Mackey, David; Tang, Dingzhong; Wei, Zhongmin; Wang, Guo-Liang

    2017-10-04

    Ferredoxins, the major distributors for electrons to various acceptor systems in plastids, contribute to redox regulation and antioxidant defense in plants. However, their function in plant immunity has not been fully understood. In this study, we show that expression of the major leaf ferredoxin gene Fd2 is suppressed by Pseudomonas syringae pv tomato (Pst) DC3000 infection, and that knock out of Fd2 (Fd2-KO) in Arabidopsis increases the plant's susceptibility to both Pst DC3000 and Golovinomyces cichoracearum. Upon Pst DC3000 infection, the Fd2-KO mutant accumulates increased levels of jasmonic acid and displays compromised salicylic acid-related immune responses. Fd2-KO also shows defects in accumulation of reactive oxygen species induced by pathogen-associated molecular pattern-triggered immunity. However, Fd2-KO shows enhanced R-protein-mediated resistance to Pst DC3000/AvrRpt2 infection, suggesting that Fd2 plays a negative role in effector-triggered immunity. Furthermore, Fd2 interacts with FIBRILLIN4 (FIB4), a harpin-binding protein localized in chloroplasts. Interestingly, Fd2, but not FIB4, localizes to stromules that extend from chloroplasts. Taken together, our results demonstrate that Fd2 play an important role in plant immunity. This article is protected by copyright. All rights reserved. © 2017 BSPP and John Wiley & Sons Ltd.

  20. Common gas phase molecules from fungi affect seed germination and plant health in Arabidopsis thaliana

    PubMed Central

    2014-01-01

    Fungal volatile organic compounds (VOCs) play important ecophysiological roles in mediating inter-kingdom signaling with arthropods but less is known about their interactions with plants. In this study, Arabidopsis thaliana was used as a model in order to test the physiological effects of 23 common vapor-phase fungal VOCs that included alcohols, aldehydes, ketones, and other chemical classes. After exposure to a shared atmosphere with the 23 individual VOCs for 72 hrs, seeds were assayed for rate of germination and seedling formation; vegetative plants were assayed for fresh weight and chlorophyll concentration. All but five of the VOCs tested (1-decene, 2-n-heptylfuran, nonanal, geosmin and -limonene) had a significant effect in inhibiting either germination, seedling formation or both. Seedling formation was entirely inhibited by exposure to 1-octen-3-one, 2-ethylhexanal, 3-methylbutanal, and butanal. As assayed by a combination of fresh weight and chlorophyll concentration, 2-ethylhexanal had a negative impact on two-week-old vegetative plants. Three other compounds (1-octen-3-ol, 2-ethylhexanal, and 2-heptylfuran) decreased fresh weight alone. Most of the VOCs tested did not change the fresh weight or chlorophyll concentration of vegetative plants. In summary, when tested as single compounds, fungal VOCs affected A. thaliana in positive, negative or neutral ways. PMID:25045602

  1. Modification of starch metabolism in transgenic Arabidopsis thaliana increases plant biomass and triples oilseed production.

    PubMed

    Liu, Fushan; Zhao, Qianru; Mano, Noel; Ahmed, Zaheer; Nitschke, Felix; Cai, Yinqqi; Chapman, Kent D; Steup, Martin; Tetlow, Ian J; Emes, Michael J

    2016-03-01

    We have identified a novel means to achieve substantially increased vegetative biomass and oilseed production in the model plant Arabidopsis thaliana. Endogenous isoforms of starch branching enzyme (SBE) were substituted by either one of the endosperm-expressed maize (Zea mays L.) branching isozymes, ZmSBEI or ZmSBEIIb. Transformants were compared with the starch-free background and with the wild-type plants. Each of the maize-derived SBEs restored starch biosynthesis but both morphology and structure of starch particles were altered. Altered starch metabolism in the transformants is associated with enhanced biomass formation and more-than-trebled oilseed production while maintaining seed oil quality. Enhanced oilseed production is primarily due to an increased number of siliques per plant whereas oil content and seed number per silique are essentially unchanged or even modestly decreased. Introduction of cereal starch branching isozymes into oilseed plants represents a potentially useful strategy to increase biomass and oilseed production in related crops and manipulate the structure and properties of leaf starch.

  2. Blocking histone deacetylation in Arabidopsis induces pleiotropic effects on plant gene regulation and development

    PubMed Central

    Tian, Lu; Chen, Z. Jeffrey

    2001-01-01

    Histone acetylation and deacetylation play essential roles in eukaryotic gene regulation. Reversible modifications of core histones are catalyzed by two intrinsic enzymes, histone acetyltransferase and histone deacetylase (HD). In general, histone deacetylation is related to transcriptional gene silencing, whereas acetylation correlates with gene activation. We produced transgenic plants expressing the antisense Arabidopsis HD (AtHD1) gene. AtHD1 is a homolog of human HD1 and RPD3 global transcriptional regulator in yeast. Expression of the antisense AtHD1 caused dramatic reduction in endogenous AtHD1 transcription, resulting in accumulation of acetylated histones, notably tetraacetylated H4. Reduction in AtHD1 expression and AtHD1 production and changes in acetylation profiles were associated with various developmental abnormalities, including early senescence, ectopic expression of silenced genes, suppression of apical dominance, homeotic changes, heterochronic shift toward juvenility, flower defects, and male and female sterility. Some of the phenotypes could be attributed to ectopic expression of tissue-specific genes (e.g., SUPERMAN) in vegetative tissues. No changes in genomic DNA methylation were detected in the transgenic plants. These results suggest that AtHD1 is a global regulator, which controls gene expression during development through DNA-sequence independent or epigenetic mechanisms in plants. In addition to DNA methylation, histone modifications may be involved in a general regulatory mechanism responsible for plant plasticity and variation in nature. PMID:11134508

  3. Arabidopsis Transcriptome Analysis Reveals Key Roles of Melatonin in Plant Defense Systems

    PubMed Central

    Weeda, Sarah; Zhang, Na; Zhao, Xiaolei; Ndip, Grace; Guo, Yangdong; Buck, Gregory A.; Fu, Conggui; Ren, Shuxin

    2014-01-01

    Melatonin is a ubiquitous molecule and exists across kingdoms including plant species. Studies on melatonin in plants have mainly focused on its physiological influence on growth and development, and on its biosynthesis. Much less attention has been drawn to its affect on genome-wide gene expression. To comprehensively investigate the role(s) of melatonin at the genomics level, we utilized mRNA-seq technology to analyze Arabidopsis plants subjected to a 16-hour 100 pM (low) and 1 mM (high) melatonin treatment. The expression profiles were analyzed to identify differentially expressed genes. 100 pM melatonin treatment significantly affected the expression of only 81 genes with 51 down-regulated and 30 up-regulated. However, 1 mM melatonin significantly altered 1308 genes with 566 up-regulated and 742 down-regulated. Not all genes altered by low melatonin were affected by high melatonin, indicating different roles of melatonin in regulation of plant growth and development under low and high concentrations. Furthermore, a large number of genes altered by melatonin were involved in plant stress defense. Transcript levels for many stress receptors, kinases, and stress-associated calcium signals were up-regulated. The majority of transcription factors identified were also involved in plant stress defense. Additionally, most identified genes in ABA, ET, SA and JA pathways were up-regulated, while genes pertaining to auxin responses and signaling, peroxidases, and those associated with cell wall synthesis and modifications were mostly down-regulated. Our results indicate critical roles of melatonin in plant defense against various environmental stresses, and provide a framework for functional analysis of genes in melatonin-mediated signaling pathways. PMID:24682084

  4. Characterization of photosystem II photochemistry in transgenic tobacco plants with lowered Rubisco activase content.

    PubMed

    Cai, Bin; Zhang, Aihong; Yang, Zhipan; Lu, Qingtao; Wen, Xiaogang; Lu, Congming

    2010-11-15

    Rubisco activase plays an important role in the regulation of CO(2) assimilation. However, it is unknown how activase regulates photosystem II (PSII) photochemistry. To investigate the effects of Rubisco activase on PSII photochemistry, we obtained transgenic tobacco (Nicotiana tabacum) plants with 50% (i7), 25% (i28), and 5% (i46) activase levels as compared to wild type plants by using a gene encoding tobacco activase for the RNAi construct. Both CO(2) assimilation and PSII activity were significantly reduced only in transgenic i28 and i46 plants, suggesting that activase deficiency led to decreased PSII activity. Flash-induced fluorescence kinetics indicated that activase deficiency resulted in a slow electron transfer between Q(A) (primary quinine electron acceptor of PSII) and Q(B) (secondary quinone electron acceptor of PSII). Thermoluminescence measurements revealed that activase deficiency induced a shift of S(2)Q(A)(-) and S(2)Q(B)(-) recombinations to higher temperatures in parallel, and a decrease in the intensities of the thermoluminescence emissions. Activase deficiency also dampened the period-four oscillation of the thermoluminescence B-band. Protein gel blot analysis showed that activase deficiency resulted in a significant decrease in the content of D1, D2, CP43, CP47, and PsbO proteins. Transmission electron microscopy analysis demonstrated that activase deficiency induced a significant decrease in the number of grana stacks per chloroplast and discs per grana stack. Our results suggest that activase plays an important role in maintaining PSII function and chloroplast development.

  5. Mechanisms of the light-dependent induction of cell death in tobacco plants with delayed senescence.

    PubMed

    Wingler, Astrid; Brownhill, Emily; Pourtau, Nathalie

    2005-11-01

    The relationship between leaf senescence and cell death was investigated using tobacco with delayed senescence due to auto-regulated production of cytokinin (SAG12-IPT). Although leaf senescence ultimately results in cell death, the results show that senescence and cell death can be uncoupled: in nutrient-deficient, but not in fertilized SAG12-IPT plants, necrotic lesions were detected in old, but otherwise green leaves. By contrast, wild-type leaves of the same age were yellow, but not necrotic. Chlorophyll fluorescence analysis revealed an over-reduction of the electron transport chain in old SAG12-IPT leaves, in combination with characteristic spatial patterns of minimum fluorescence (F0) quantum efficiency of open photosystem II centres (F(v)/F(m)) and non-photochemical quenching (NPQ), as determined by fluorescence imaging. The same patterns of F0, F(v)/F(m), and NPQ were induced by incubation of leaf discs from nutrient-deficient SAG12-IPT plants under illumination, but not in the dark, indicating that light-dependent reactions were responsible for the cell death. RT-PCR analysis showed that the pathogenesis-related (PR) genes PR-1b and PR-Q were strongly induced in old SAG12-IPT tobacco leaves with necrotic lesions. In addition, the ethylene-synthesis gene ACO was induced before lesions became visible in SAG12-IPT. It is proposed that over-reduction of the electron transport chain in combination with decreased electron consumption due to nutrient-deficiency led to oxidative stress, which, mediated by ethylene formation, can induce PR gene expression and hypersensitive cell death. Probably as a consequence of inefficient nutrient mobilization, flower development was prematurely aborted and reproduction thereby impaired in nutrient-deficient SAG12-IPT plants.

  6. The allotetraploid Arabidopsis thaliana-Arabidopsis lyrata subsp. petraea as an alternative model system for the study of polyploidy in plants.

    PubMed

    Beaulieu, Julien; Jean, Martine; Belzile, François

    2009-04-01

    Polyploidy is known to be common in plants and recent work has focused on the rapid changes in genome structure and expression that occur upon polyploidization. In Arabidopsis, much of this work has been done on a synthetic allotetraploid obtained by crossing a tetraploid Arabidopsis thaliana (2n = 4x = 20) with A. arenosa (2n = 4x = 32). To explore an alternative route to polyploidy in this model species, we have developed a synthetic allopolyploid by crossing two diploid species: A. thaliana (2n = 2x = 10) and Arabidopsis lyrata subsp. petraea (2n = 2x = 16). F(1) hybrids were easy to obtain and phenotypically more similar to A. lyrata. Spontaneous chromosome doubling events occurred in about 25% of the F(1)s, thus restoring fertility. The resulting allotetraploids (2n = 26) exhibited many genomic changes typically reported upon polyploidization. Nucleolar dominance was observed as only the A. lyrata rDNA loci were expressed in the F(1) and allotetraploids. Changes in the degree of methylation were observed at almost 25% of the loci examined by MSAP analysis. Finally, structural genomic alterations did occur as a large deletion covering a significant portion of the upper arm of chromosome II was detected but no evidence of increased mobility of transposons was obtained. Such allotetraploids derived from two parents with sequenced (or soon to be sequenced) genomes offer much promise in elucidating the various changes that occur in newly synthesized polyploids.

  7. The role of K+ channels in uptake and redistribution of potassium in the model plant Arabidopsis thaliana

    PubMed Central

    Sharma, Tripti; Dreyer, Ingo; Riedelsberger, Janin

    2013-01-01

    Potassium (K+) is inevitable for plant growth and development. It plays a crucial role in the regulation of enzyme activities, in adjusting the electrical membrane potential and the cellular turgor, in regulating cellular homeostasis and in the stabilization of protein synthesis. Uptake of K+ from the soil and its transport to growing organs is essential for a healthy plant development. Uptake and allocation of K+ are performed by K+ channels and transporters belonging to different protein families. In this review we summarize the knowledge on the versatile physiological roles of plant K+ channels and their behavior under stress conditions in the model plant Arabidopsis thaliana. PMID:23818893

  8. Plant development. Arabidopsis NAC45/86 direct sieve element morphogenesis culminating in enucleation.

    PubMed

    Furuta, Kaori Miyashima; Yadav, Shri Ram; Lehesranta, Satu; Belevich, Ilya; Miyashima, Shunsuke; Heo, Jung-ok; Vatén, Anne; Lindgren, Ove; De Rybel, Bert; Van Isterdael, Gert; Somervuo, Panu; Lichtenberger, Raffael; Rocha, Raquel; Thitamadee, Siripong; Tähtiharju, Sari; Auvinen, Petri; Beeckman, Tom; Jokitalo, Eija; Helariutta, Ykä

    2014-08-22

    Photoassimilates such as sugars are transported through phloem sieve element cells in plants. Adapted for effective transport, sieve elements develop as enucleated living cells. We used electron microscope imaging and three-dimensional reconstruction to follow sieve element morphogenesis in Arabidopsis. We show that sieve element differentiation involves enucleation, in which the nuclear contents are released and degraded in the cytoplasm at the same time as other organelles are rearranged and the cytosol is degraded. These cellular reorganizations are orchestrated by the genetically redundant NAC domain-containing transcription factors, NAC45 and NAC86 (NAC45/86). Among the NAC45/86 targets, we identified a family of genes required for enucleation that encode proteins with nuclease domains. Thus, sieve elements differentiate through a specialized autolysis mechanism.

  9. Cell Proliferation Analysis Using EdU Labeling in Whole Plant and Histological Samples of Arabidopsis.

    PubMed

    Kazda, Anita; Akimcheva, Svetlana; Watson, J Matthew; Riha, Karel

    2016-01-01

    The ability to analyze cell division in both spatial and temporal dimensions within an organism is a key requirement in developmental biology. Specialized cell types within individual organs, such as those within shoot and root apical meristems, have often been identified by differences in their rates of proliferation prior to the characterization of distinguishing molecular markers. Replication-dependent labeling of DNA is a widely used method for assaying cell proliferation. The earliest approaches used radioactive labeling with tritiated thymidine, which were later followed by immunodetection of bromodeoxyuridine (BrdU). A major advance in DNA labeling came with the use of 5-ethynyl-2'deoxyuridine (EdU) which has proven to have multiple advantages over BrdU. Here we describe the methodology for analyzing EdU labeling and retention in whole plants and histological sections of Arabidopsis.

  10. Expression of a chitinase gene from Metarhizium anisopliae in tobacco plants confers resistance against Rhizoctonia solani.

    PubMed

    Kern, Marcelo Fernando; Maraschin, Simone de Faria; Vom Endt, Débora; Schrank, Augusto; Vainstein, Marilene Henning; Pasquali, Giancarlo

    2010-04-01

    The chit1 gene from the entomopathogenic fungus Metarhizium anisopliae, encoding the endochitinase CHIT42, was placed under the control of the CaMV 35S promoter, and the resulting construct was transferred to tobacco. Seventeen kanamycin-resistant transgenic lines were recovered, and the presence of the transgene was confirmed by polymerase chain reactions and Southern blot hybridization. The number of chit1 copies was determined to be varying from one to four. Copy number had observable effects neither on plant growth nor development. Substantial heterogeneity concerning production of the recombinant chitinase, and both general and specific chitinolytic activities were detected in leaf extracts from primary transformants. The highest chitinase activities were found in plants harboring two copies of chit1 inserts at different loci. Progeny derived from self-pollination of the primary transgenics revealed a stable inheritance pattern, with transgene segregation following a mendelian dihybrid ratio. Two selected plants expressing high levels of CHIT42 were consistently resistant to the soilborne pathogen Rhizoctonia solani, suggesting a direct relationship between enzyme activity and reduction of foliar area affected by fungal lesions. To date, this is the first report of resistance to fungal attack in plants mediated by a recombinant chitinase from an entomopathogenic and acaricide fungus.

  11. Light-dependent regulation of chlorophyll b biosynthesis in chlorophyllide a oxygenase overexpressing tobacco plants.

    PubMed

    Pattanayak, Gopal K; Biswal, Ajaya K; Reddy, Vanga S; Tripathy, Baishnab C

    2005-01-14

    Chlorophyllide a oxygenase (CAO) that converts chlorophyllide a to chlorophyllide b was overexpressed in tobacco to increase chlorophyll (Chl) b biosynthesis and alter the Chl a/b ratio. Transgenic plants along with their wild-type cultivars were grown in low and high light intensities. In low light there was 20% increase in chlorophyll b contents in transgenic plants, which resulted in 16% reduction in the Chl a/b ratio. In high light, total Chl contents were 31% higher in transgenic plants than those of wild type. The increase in Chl a was 19% and that of Chl b was 72% leading to 31% decline of Chl a/b ratio. The increase in Chl b contents was accompanied by enhanced CAO expression that was highly pronounced in low light. As compared to low light, in high light Lhcb1 and Chl a/b transcripts abundance was significantly increased in transgenic plants suggesting a close relationship between Chl b synthesis and cab gene expression. However, there was a small increase in expression of LHCII proteins, which did not correspond to 72% increase in Chl b content in transgenic line, implying that LHCPII has the ability to bind more Chl b molecules.

  12. Exploitation of natural genetic diversity to study plant-virus interactions: what can we learn from Arabidopsis thaliana?

    PubMed

    Ouibrahim, Laurence; Caranta, Carole

    2013-10-01

    The development and use of cultivars that are genetically resistant to viruses is an efficient strategy to tackle the problems of virus diseases. Over the past two decades, the model plant Arabidopsis thaliana has been documented as a host for a broad range of viral species, providing access to a large panel of resources and tools for the study of viral infection processes and resistance mechanisms. Exploration of its natural genetic diversity has revealed a wide range of genes conferring virus resistance. The molecular characterization of some of these genes has unveiled resistance mechanisms distinct from those described in crops. In these respects, Arabidopsis represents a rich and largely untapped source of new genes and mechanisms involved in virus resistance. Here, we review the current status of our knowledge concerning natural virus resistance in Arabidopsis. We also address the impact of environmental conditions on Arabidopsis-virus interactions and resistance mechanisms, and discuss the potential of applying the knowledge gained from the study of Arabidopsis natural diversity for crop improvement.

  13. Expression of root glutamate dehydrogenase genes in tobacco plants subjected to boron deprivation.

    PubMed

    Beato, Víctor M; Teresa Navarro-Gochicoa, M; Rexach, Jesús; Begoña Herrera-Rodríguez, M; Camacho-Cristóbal, Juan J; Kempa, Stefan; Weckwerth, Wolfram; González-Fontes, Agustín

    2011-11-01

    Recently it has been reported that boron (B) deficiency increases the expression of Nicotiana tabacum asparagine synthetase (AS) gene in roots, and that AS might play a main role as a detoxifying mechanism to convert ammonium into asparagine. Interestingly, glutamate dehydrogenase (GDH) genes, Ntgdh-NAD;A1 and Ntgdh-NAD;B2, were up-regulated when tobacco roots were subjected to B deprivation for 8 and 24 h. In addition, aminating and deaminating GDH (EC 1.4.1.2) activities were higher in B-deficient than in B-sufficient plants after 24 h of B deficiency. Ammonium concentrations were kept sufficiently low and with similar values in B-deficient roots when compared to control. Glucose and fructose contents decreased after 24 h of B deprivation. This drop in hexoses, which was corroborated by metabolomic analysis, correlated with higher GDH gene expression. Furthermore, metabolomic profiling showed that concentrations of several organic acids, phenolics, and amino acids increased after 24 h of B deficiency. Our results suggest that GDH enzyme plays an important role in metabolic acclimation of tobacco roots to B deprivation. A putative model to explain these results is proposed and discussed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  14. Female sterile tobacco plants are produced by stigma-specific cell ablation.

    PubMed Central

    Goldman, M H; Goldberg, R B; Mariani, C

    1994-01-01

    We identified a tobacco stigma-specific gene, designated STIG1. The STIG1 gene is developmentally regulated and expressed specifically in the stigmatic secretory zone. We used a chimeric STIG1-GUS gene to show that the stigma-specific STIG1 gene expression pattern is controlled primarily at the transcriptional level. We constructed a stigma-specific cytotoxic gene by fusing the STIG1 gene 5' regulatory region with the coding sequence of the Bacillus amyloliquefaciens barnase gene, to assess the role of the stigmatic secretory zone in the pollination process. Pistils of transgenic STIG1-barnase tobacco plants undergo normal development, but lack the stigmatic secretory zone and are female sterile. Pollen grains germinate on the ablated 'stigmatic' surface, but are unable to penetrate the transmitting tissue of the style. Application of stigmatic exudate from wild-type pistils to the ablated surface increases the efficiency of pollen tube germination and growth and restores the capacity of pollen tubes to penetrate the style. Our data demonstrate the importance of the stigmatic secretory zone in the pollination process and provide an approach to identify compounds produced by the stigma that are critical for successful pollination and fertilization to occur. Images PMID:8039494

  15. Protocol: optimising hydroponic growth systems for nutritional and physiological analysis of Arabidopsis thaliana and other plants

    PubMed Central

    2013-01-01

    Background Hydroponic growth systems are a convenient platform for studying whole plant physiology. However, we found through trialling systems as they are described in the literature that our experiments were frequently confounded by factors that affected plant growth, including algal contamination and hypoxia. We also found the way in which the plants were grown made them poorly amenable to a number of common physiological assays. Results The drivers for the development of this hydroponic system were: 1) the exclusion of light from the growth solution; 2) to simplify the handling of individual plants, and 3) the growth of the plant to allow easy implementation of multiple assays. These aims were all met by the use of pierced lids of black microcentrifuge tubes. Seed was germinated on a lid filled with an agar-containing germination media immersed in the same solution. Following germination, the liquid growth media was exchanged with the experimental solution, and after 14-21 days seedlings were transferred to larger tanks with aerated solution where they remained until experimentation. We provide details of the protocol including composition of the basal growth solution, and separate solutions with altered calcium, magnesium, potassium or sodium supply whilst maintaining the activity of the majority of other ions. We demonstrate the adaptability of this system for: gas exchange measurement on single leaves and whole plants; qRT-PCR to probe the transcriptional response of roots or shoots to altered nutrient composition in the growth solution (we demonstrate this using high and low calcium supply); producing highly competent mesophyll protoplasts; and, accelerating the screening of Arabidopsis transformants. This system is also ideal for manipulating plants for micropipette techniques such as electrophysiology or SiCSA. Conclusions We present an optimised plant hydroponic culture system that can be quickly and cheaply constructed, and produces plants with similar

  16. Enhanced Whitefly Resistance in Transgenic Tobacco Plants Expressing Double Stranded RNA of v-ATPase A Gene

    PubMed Central

    Thakur, Nidhi; Upadhyay, Santosh Kumar; Verma, Praveen C.; Chandrashekar, Krishnappa; Tuli, Rakesh; Singh, Pradhyumna K.

    2014-01-01

    Background Expression of double strand RNA (dsRNA) designed against important insect genes in transgenic plants have been shown to give protection against pests through RNA interference (RNAi), thus opening the way for a new generation of insect-resistant crops. We have earlier compared the efficacy of dsRNAs/siRNAs, against a number of target genes, for interference in growth of whitefly (Bemisia tabaci) upon oral feeding. The v-ATPase subunit A (v-ATPaseA) coding gene was identified as a crucial target. We now report the effectiveness of transgenic tobacco plants expressing siRNA to silence v-ATPaseA gene expression for the control of whitefly infestation. Methodology/Principal Findings Transgenic tobacco lines were developed for the expression of long dsRNA precursor to make siRNA and knock down the v-ATPaseA mRNA in whitefly. Molecular analysis and insecticidal properties of the transgenic plants established the formation of siRNA targeting the whitefly v-ATPaseA, in the leaves. The transcript level of v-ATPaseA in whiteflies was reduced up to 62% after feeding on the transgenic plants. Heavy infestation of whiteflies on the control plants caused significant loss of sugar content which led to the drooping of leaves. The transgenic plants did not show drooping effect. Conclusions/Significance Host plant derived pest resistance was achieved against whiteflies by genetic transformation of tobacco which generated siRNA against the whitefly v-ATPaseA gene. Transgenic tobacco lines expressing dsRNA of v-ATPaseA, delivered sufficient siRNA to whiteflies feeding on them, mounting a significant silencing response, leading to their mortality. The transcript level of the target gene was reduced in whiteflies feeding on transgenic plants. The strategy can be taken up for genetic engineering of plants to control whiteflies in field crops. PMID:24595215

  17. Enhanced whitefly resistance in transgenic tobacco plants expressing double stranded RNA of v-ATPase A gene.

    PubMed

    Thakur, Nidhi; Upadhyay, Santosh Kumar; Verma, Praveen C; Chandrashekar, Krishnappa; Tuli, Rakesh; Singh, Pradhyumna K

    2014-01-01

    Expression of double strand RNA (dsRNA) designed against important insect genes in transgenic plants have been shown to give protection against pests through RNA interference (RNAi), thus opening the way for a new generation of insect-resistant crops. We have earlier compared the efficacy of dsRNAs/siRNAs, against a number of target genes, for interference in growth of whitefly (Bemisia tabaci) upon oral feeding. The v-ATPase subunit A (v-ATPaseA) coding gene was identified as a crucial target. We now report the effectiveness of transgenic tobacco plants expressing siRNA to silence v-ATPaseA gene expression for the control of whitefly infestation. Transgenic tobacco lines were developed for the expression of long dsRNA precursor to make siRNA and knock down the v-ATPaseA mRNA in whitefly. Molecular analysis and insecticidal properties of the transgenic plants established the formation of siRNA targeting the whitefly v-ATPaseA, in the leaves. The transcript level of v-ATPaseA in whiteflies was reduced up to 62% after feeding on the transgenic plants. Heavy infestation of whiteflies on the control plants caused significant loss of sugar content which led to the drooping of leaves. The transgenic plants did not show drooping effect. Host plant derived pest resistance was achieved against whiteflies by genetic transformation of tobacco which generated siRNA against the whitefly v-ATPaseA gene. Transgenic tobacco lines expressing dsRNA of v-ATPaseA, delivered sufficient siRNA to whiteflies feeding on them, mounting a significant silencing response, leading to their mortality. The transcript level of the target gene was reduced in whiteflies feeding on transgenic plants. The strategy can be taken up for genetic engineering of plants to control whiteflies in field crops.

  18. Plant Vascular Architecture Determines the Pattern of Herbivore-Induced Systemic Responses in Arabidopsis thaliana

    PubMed Central

    Ferrieri, Abigail P.; Appel, Heidi M.; Schultz, Jack C.

    2015-01-01

    The induction of systemic responses in plants is associated with the connectivity between damaged and undamaged leaves, as determined by vascular architecture. Despite the widespread appreciation for studying variation in induced plant defense, few studies have characterized spatial variability of induction in the model species, Arabidopsis thaliana. Here we show that plant architecture generates fine scale spatial variation in the systemic induction of invertase and phenolic compounds. We examined whether the arrangement of leaves along the stem (phyllotaxy) produces predictable spatial patterns of cell-wall bound and soluble invertase activities, and downstream phenolic accumulation following feeding by the dietary specialist herbivore, Pieris rapae and the generalist, Spodoptera exigua. Responses were measured in leaves within and outside of the damaged orthostichy (leaves sharing direct vascular connections), and compared to those from plants where source-sink transport was disrupted by source leaf removal and by an insertional mutation in a sucrose transporter gene (suc2-1). Following herbivore damage to a single, middle-aged leaf, induction of cell-wall and soluble invertase was most pronounced in young and old leaves within the damaged orthostichy. The pattern of accumulation of phenolics was also predicted by these vascular connections and was, in part, dependent on the presence of source leaves and intact sucrose transporter function. Induction also occurred in leaves outside of the damaged orthostichy, suggesting that mechanisms may exist to overcome vascular constraints in this system. Our results demonstrate that systemic responses vary widely according to orthostichy, are often herbivore-specific, and partially rely on transport between source and sink leaves. We also provide evidence that patterns of induction are more integrated in A. thaliana than previously described. This work highlights the importance of plant vascular architecture in determining

  19. Interaction between parental environment and genotype affects plant and seed performance in Arabidopsis.

    PubMed

    He, Hanzi; de Souza Vidigal, Deborah; Snoek, L Basten; Schnabel, Sabine; Nijveen, Harm; Hilhorst, Henk; Bentsink, Leónie

    2014-12-01

    Seed performance after dispersal is highly dependent on parental environmental cues, especially during seed formation and maturation. Here we examine which environmental factors are the most dominant in this respect and whether their effects are dependent on the genotypes under investigation. We studied the influence of light intensity, photoperiod, temperature, nitrate, and phosphate during seed development on five plant attributes and thirteen seed attributes, using 12 Arabidopsis genotypes that have been reported to be affected in seed traits. As expected, the various environments during seed development resulted in changed plant and/or seed performances. Comparative analysis clearly indicated that, overall, temperature plays the most dominant role in both plant and seed performance, whereas light has a prominent impact on plant traits. In comparison to temperature and light, nitrate mildly affected some of the plant and seed traits while phosphate had even less influence on those traits. Moreover, clear genotype-by-environment interactions were identified. This was shown by the fact that individual genotypes responded differentially to the environmental conditions. Low temperature significantly increased seed dormancy and decreased seed longevity of NILDOG1 and cyp707a1-1, whereas low light intensity increased seed dormancy and decreased seed longevity of NILDOG3 and NILDOG6. This also indicates that different genetic and molecular pathways are involved in the plant and seed responses. By identifying environmental conditions that affect the dormancy vs longevity correlation in the same way as previously identified naturally occurring loci, we have identified selective forces that probably shaped evolution for these important seed traits.

  20. Interaction between parental environment and genotype affects plant and seed performance in Arabidopsis

    PubMed Central

    He, Hanzi; de Souza Vidigal, Deborah; Snoek, L. Basten; Schnabel, Sabine; Nijveen, Harm; Hilhorst, Henk; Bentsink, Leónie

    2014-01-01

    Seed performance after dispersal is highly dependent on parental environmental cues, especially during seed formation and maturation. Here we examine which environmental factors are the most dominant in this respect and whether their effects are dependent on the genotypes under investigation. We studied the influence of light intensity, photoperiod, temperature, nitrate, and phosphate during seed development on five plant attributes and thirteen seed attributes, using 12 Arabidopsis genotypes that have been reported to be affected in seed traits. As expected, the various environments during seed development resulted in changed plant and/or seed performances. Comparative analysis clearly indicated that, overall, temperature plays the most dominant role in both plant and seed performance, whereas light has a prominent impact on plant traits. In comparison to temperature and light, nitrate mildly affected some of the plant and seed traits while phosphate had even less influence on those traits. Moreover, clear genotype-by-environment interactions were identified. This was shown by the fact that individual genotypes responded differentially to the environmental conditions. Low temperature significantly increased seed dormancy and decreased seed longevity of NILDOG1 and cyp707a1-1, whereas low light intensity increased seed dormancy and decreased seed longevity of NILDOG3 and NILDOG6. This also indicates that different genetic and molecular pathways are involved in the plant and seed responses. By identifying environmental conditions that affect the dormancy vs longevity correlation in the same way as previously identified naturally occurring loci, we have identified selective forces that probably shaped evolution for these important seed traits. PMID:25240065

  1. Plant vascular architecture determines the pattern of herbivore-induced systemic responses in Arabidopsis thaliana.

    PubMed

    Ferrieri, Abigail P; Appel, Heidi M; Schultz, Jack C

    2015-01-01

    The induction of systemic responses in plants is associated with the connectivity between damaged and undamaged leaves, as determined by vascular architecture. Despite the widespread appreciation for studying variation in induced plant defense, few studies have characterized spatial variability of induction in the model species, Arabidopsis thaliana. Here we show that plant architecture generates fine scale spatial variation in the systemic induction of invertase and phenolic compounds. We examined whether the arrangement of leaves along the stem (phyllotaxy) produces predictable spatial patterns of cell-wall bound and soluble invertase activities, and downstream phenolic accumulation following feeding by the dietary specialist herbivore, Pieris rapae and the generalist, Spodoptera exigua. Responses were measured in leaves within and outside of the damaged orthostichy (leaves sharing direct vascular connections), and compared to those from plants where source-sink transport was disrupted by source leaf removal and by an insertional mutation in a sucrose transporter gene (suc2-1). Following herbivore damage to a single, middle-aged leaf, induction of cell-wall and soluble invertase was most pronounced in young and old leaves within the damaged orthostichy. The pattern of accumulation of phenolics was also predicted by these vascular connections and was, in part, dependent on the presence of source leaves and intact sucrose transporter function. Induction also occurred in leaves outside of the damaged orthostichy, suggesting that mechanisms may exist to overcome vascular constraints in this system. Our results demonstrate that systemic responses vary widely according to orthostichy, are often herbivore-specific, and partially rely on transport between source and sink leaves. We also provide evidence that patterns of induction are more integrated in A. thaliana than previously described. This work highlights the importance of plant vascular architecture in determining

  2. Arabidopsis plants exposed to gamma radiation in two successive generations show a different oxidative stress response.

    PubMed

    van de Walle, Jorden; Horemans, Nele; Saenen, Eline; Van Hees, May; Wannijn, Jean; Nauts, Robin; van Gompel, Axel; Vangronsveld, Jaco; Vandenhove, Hildegarde; Cuypers, Ann

    2016-12-01

    When terrestrial environments get contaminated with long-lived gamma emitting radionuclides, plants that grow in these contaminated areas are exposed to gamma radiation during consecutive generations. Therefore it is important to evaluate the gamma induced stress response in plants in and between generations. The objective of this research is to reveal differences at the level of the antioxidative stress response between generations with a different radiation history. An experiment was conducted in which 7-days old Arabidopsis thaliana plants were exposed for 14 days to four different gamma dose rates: 22 mGy/h, 38 mGy/h, 86 mGy/h and 457 mGy/h. Two different plant groups were used: plants that were not exposed to gamma radiation before (P0) and plants that received the aforementioned gamma treatment during their previous generation (S1). Growth, the concentration of the antioxidants ascorbate and glutathione, a number of antioxidative enzyme activities and their gene transcript levels were analysed. A dose-rate dependent induction was seen for catalase (CAT) and guaiacol peroxidase (GPX) in the roots and for syringaldazine peroxidase (SPX) in the shoots. Differences between the two generations were observed for CAT and GPX in the roots, where a significantly higher activity of these reactive oxygen species (ROS) detoxifying enzymes was observed in the S1 generation. For SPX in the shoots, a dose dependent upregulation was observed in the P0 generation. However, high SPX activities were present for all doses in the S1 generation. These differences in enzyme activity between generations for SPX and GPX and the involvement of these enzymes in cell wall biosynthesis, suggest an important role for cell wall strengthening in the response to gamma irradiation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Overexpression of the Wheat Expansin Gene TaEXPA2 Improved Seed Production and Drought Tolerance in Transgenic Tobacco Plants.

    PubMed

    Chen, Yanhui; Han, Yangyang; Zhang, Meng; Zhou, Shan; Kong, Xiangzhu; Wang, Wei

    2016-01-01

    Expansins are cell wall proteins that are grouped into two main families, α-expansins and β-expansins, and they are implicated in the control of cell extension via the disruption of hydrogen bonds between cellulose and matrix glucans. TaEXPA2 is an α-expansin gene identified in wheat. Based on putative cis-regulatory elements in the TaEXPA2 promoter sequence and the expression pattern induced when polyethylene glycol (PEG) is used to mimic water stress, we hypothesized that TaEXPA2 is involved in plant drought tolerance and plant development. Through transient expression of 35S::TaEXPA2-GFP in onion epidermal cells, TaEXPA2 was localized to the cell wall. Constitutive expression of TaEXPA2 in tobacco improved seed production by increasing capsule number, not seed size, without having any effect on plant growth patterns. The transgenic tobacco exhibited a significantly greater tolerance to water-deficiency stress than did wild-type (WT) plants. We found that under drought stress, the transgenic plants maintained a better water status. The accumulated content of osmotic adjustment substances, such as proline, in TaEXPA2 transgenic plants was greater than that in WT plants. Transgenic plants also displayed greater antioxidative competence as indicated by their lower malondialdehyde (MDA) content, relative electrical conductivity, and reactive oxygen species (ROS) accumulation than did WT plants. This result suggests that the transgenic plants suffer less damage from ROS under drought conditions. The activities of some antioxidant enzymes as well as expression levels of several genes encoding key antioxidant enzymes were higher in the transgenic plants than in the WT plants under drought stress. Collectively, our results suggest that ectopic expression of the wheat expansin gene TaEXPA2 improves seed production and drought tolerance in transgenic tobacco plants.

  4. How does a plant orchestrate defense in time and space? Using glucosinolates in Arabidopsis as case study.

    PubMed

    Burow, Meike; Halkier, Barbara Ann

    2017-08-01

    The sessile nature of plants has caused plants to develop means to defend themselves against attacking organisms. Multiple strategies range from physical barriers to chemical warfare including pre-formed anticipins as well as phytoalexins produced only upon attack. While phytoalexins require rapid induction, constitutive defenses can impose ecological costs if they deter pollinators or attract specialized herbivores. In the model Arabidopsis thaliana, the well-characterized glucosinolate anticipins are categorized into different classes, aliphatic and indole glucosinolates, depending on their amino acid precursor. Using glucosinolates in Arabidopsis as case study, we will discuss how plants orchestrate synthesis, storage and activation of pre-formed defense compounds spatially and temporally. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Arabidopsis thaliana—Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids

    PubMed Central

    Louis, Joe; Shah, Jyoti

    2013-01-01

    The phloem provides a unique niche for several organisms. Aphids are a large group of Hemipteran insects that utilize stylets present in their mouthparts to pierce sieve elements and drink large volumes of phloem sap. In addition, many aphids also vector viral diseases. Myzus persicae, commonly known as the green peach aphid (GPA), is an important pest of a large variety of plants that includes Arabidopsis thaliana. This review summarizes recent studies that have exploited the compatible interaction between Arabidopsis and GPA to understand the molecular and physiological mechanisms utilized by plants to control aphid infestation, as well as genes and mechanisms that contribute to susceptibility. In addition, recent efforts to identify aphid-delivered elicitors of plant defenses and novel aphid salivary components that facilitate infestation are also discussed. PMID:23847627

  6. The pharmaceutics from the foreign empire: the molecular pharming of the prokaryotic staphylokinase in Arabidopsis thaliana plants.

    PubMed

    Hnatuszko-Konka, Katarzyna; Łuchniak, Piotr; Wiktorek-Smagur, Aneta; Gerszberg, Aneta; Kowalczyk, Tomasz; Gatkowska, Justyna; Kononowicz, Andrzej K

    2016-07-01

    Here, we present the application of microbiology and biotechnology for the production of recombinant pharmaceutical proteins in plant cells. To the best of our knowledge and belief it is one of few examples of the expression of the prokaryotic staphylokinase (SAK) in the eukaryotic system. Despite the tremendous progress made in the plant biotechnology, most of the heterologous proteins still accumulate to low concentrations in plant tissues. Therefore, the composition of expression cassettes to assure economically feasible level of protein production in plants remains crucial. The aim of our research was obtaining a high concentration of the bacterial anticoagulant factor-staphylokinase, in Arabidopsis thaliana seeds. The coding sequence of staphylokinase was placed under control of the β-phaseolin promoter and cloned between the signal sequence of the seed storage protein 2S2 and the carboxy-terminal KDEL signal sequence. The engineered binary vector pATAG-sak was introduced into Arabidopsis thaliana plants via Agrobacterium tumefaciens-mediated transformation. Analysis of the subsequent generations of Arabidopsis seeds revealed both presence of the sak and nptII transgenes, and the SAK protein. Moreover, a plasminogen activator activity of staphylokinase was observed in the protein extracts from seeds, while such a reaction was not observed in the leaf extracts showing seed-specific activity of the β-phaseolin promoter.

  7. The sunflower transcription factor HaHB11 improves yield, biomass and tolerance to flooding in transgenic Arabidopsis plants.

    PubMed

    Cabello, Julieta V; Giacomelli, Jorge I; Piattoni, Claudia V; Iglesias, Alberto A; Chan, Raquel L

    2016-03-20

    HaHB11 is a member of the sunflower homeodomain-leucine zipper I subfamily of transcription factors. The analysis of a sunflower microarray hybridized with RNA from HaHB11-transformed leaf-disks indicated the regulation of many genes encoding enzymes from glycolisis and fermentative pathways. A 1300bp promoter sequence, fused to the GUS reporter gene, was used to transform Arabidopsis plants showing an induction of expression after flooding treatments, concurrently with HaHB11 regulation by submergence in sunflower. Arabidopsis transgenic plants expressing HaHB11 under the control of the CaMV 35S promoter and its own promoter were obtained and these plants exhibited significant increases in rosette and stem biomass. All the lines produced more seeds than controls and particularly, those of high expression level doubled seeds yield. Transgenic plants also showed tolerance to flooding stress, both to submergence and waterlogging. Carbohydrates contents were higher in the transgenics compared to wild type and decreased less after submergence treatments. Finally, transcript levels of selected genes involved in glycolisis and fermentative pathways as well as the corresponding enzymatic activities were assessed both, in sunflower and transgenic Arabidopsis plants, before and after submergence. Altogether, the present work leads us to propose HaHB11 as a biotechnological tool to improve crops yield, biomass and flooding tolerance. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Complete Genome Sequence of Paenibacillus polymyxa YC0136, a Plant Growth–Promoting Rhizobacterium Isolated from Tobacco Rhizosphere

    PubMed Central

    Liu, Hu; Liu, Kai; Li, Yuhuan; Wang, Chengqiang; Hou, Qihui; Xu, Wenfeng; Fan, Lingchao; Zhao, Jian; Gou, Jianyu

    2017-01-01

    ABSTRACT Paenibacillus polymyxa strain YC0136 is a plant growth–promoting rhizobacterium with antimicrobial activity, which was isolated from tobacco rhizosphere. Here, we report the complete genome sequence of P. polymyxa YC0136. Several genes with antifungal and antibacterial activity were discovered. PMID:28183774

  9. [Ectopic expression of the PnANTL1 and PnANTL2 black poplar genes in transgenic tobacco plants].

    PubMed

    Kuluev, B R; Kniazev, A V; Il'iasova, A A; Chemeris, A V

    2012-10-01

    Four putative orthologs of the AINTEGUMENTA gene were found in the poplar (Populus trichocarpa) genome. Two of them, which we called PnANTL1 and PnANTL2, were isolated from black poplar (Populus nigra L.) and transgenic tobacco plants were generated on their basis. Tobacco plants that were transgenic for the PnANTL1 gene were characterized by increased leaf length, smaller flower size, and different defects in the development of the corolla and stamens. Tobacco plants that were transgenic for the PnANTL2 gene were characterized by an increased length of leaves and larger flowers. The increase in the leaf size in all transgenic plants was determined by stimulation of cell expansion; the number of cells was even reduced in the case of the PnANTL1 gene. Ectopic expression of the PnANTL1 and PnANTL2 genes promoted an increase in the level of mRNA of some tobacco expansins. The data we obtained demonstrate the involvement of transcription factors of the AP2 subfamily in the regulation of cell expansion.

  10. [The creation of transgenic tobacco plants expressing fragments of the ARGOS and NtEXPA4 genes in antisense orientation].

    PubMed

    Kuluev, B R; Kniazev, A V; Postrigan', B N; Chemeris, A V

    2014-01-01

    Transgenic tobacco plants expressing the fragments of the ARGOS and NtEXPA4 genes in antisense orientation have been created. Eleven lines of transgenic plants were investigated and five of them were characterized by a decrease in the sizes of the leaves and flowers as compared to control. Stalk sizes decreased when only the NtEXPA4 gene fragment was used. The organ size of the experimental plants decreased because of a reduction in the level of both cell division and cell expansion. Two lines of transgenic tobacco plants expressing the part of the ARGOS gene in antisense orientation were characterized by a reduction in the level of the NtEXPA1 and NtEXPA4 gene expression.

  11. Balancing of B6 Vitamers Is Essential for Plant Development and Metabolism in Arabidopsis.

    PubMed

    Colinas, Maite; Eisenhut, Marion; Tohge, Takayuki; Pesquera, Marta; Fernie, Alisdair R; Weber, Andreas P M; Fitzpatrick, Teresa B

    2016-02-01

    Vitamin B6 comprises a family of compounds that is essential for all organisms, most notable among which is the cofactor pyridoxal 5'-phosphate (PLP). Other forms of vitamin B6 include pyridoxamine 5'-phosphate (PMP), pyridoxine 5'-phosphate (PNP), and the corresponding nonphosphorylated derivatives. While plants can biosynthesize PLP de novo, they also have salvage pathways that serve to interconvert the different vitamers. The selective contribution of these various pathways to cellular vitamin B6 homeostasis in plants is not fully understood. Although biosynthesis de novo has been extensively characterized, the salvage pathways have received comparatively little attention in plants. Here, we show that the PMP/PNP oxidase PDX3 is essential for balancing B6 vitamer levels in Arabidopsis thaliana. In the absence of PDX3, growth and development are impaired and the metabolite profile is altered. Surprisingly, RNA sequencing reveals strong induction of stress-related genes in pdx3, particularly those associated with biotic stress that coincides with an increase in salicylic acid levels. Intriguingly, exogenous ammonium rescues the growth and developmental phenotype in line with a severe reduction in nitrate reductase activity that may be due to the overaccumulation of PMP in pdx3. Our analyses demonstrate an important link between vitamin B6 homeostasis and nitrogen metabolism.

  12. Balancing of B6 Vitamers Is Essential for Plant Development and Metabolism in Arabidopsis

    PubMed Central

    Tohge, Takayuki; Fernie, Alisdair R.

    2016-01-01

    Vitamin B6 comprises a family of compounds that is essential for all organisms, most notable among which is the cofactor pyridoxal 5′-phosphate (PLP). Other forms of vitamin B6 include pyridoxamine 5′-phosphate (PMP), pyridoxine 5′-phosphate (PNP), and the corresponding nonphosphorylated derivatives. While plants can biosynthesize PLP de novo, they also have salvage pathways that serve to interconvert the different vitamers. The selective contribution of these various pathways to cellular vitamin B6 homeostasis in plants is not fully understood. Although biosynthesis de novo has been extensively characterized, the salvage pathways have received comparatively little attention in plants. Here, we show that the PMP/PNP oxidase PDX3 is essential for balancing B6 vitamer levels in Arabidopsis thaliana. In the absence of PDX3, growth and development are impaired and the metabolite profile is altered. Surprisingly, RNA sequencing reveals strong induction of stress-related genes in pdx3, particularly those associated with biotic stress that coincides with an increase in salicylic acid levels. Intriguingly, exogenous ammonium rescues the growth and developmental phenotype in line with a severe reduction in nitrate reductase activity th