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Sample records for 3-acetic acid iaa

  1. Immunohistochemical observation of indole-3-acetic acid at the IAA synthetic maize coleoptile tips

    PubMed Central

    Nishimura, Takeshi; Toyooka, Kiminori; Sato, Mayuko; Matsumoto, Sachiko; Lucas, M. Mercedes; Strnad, Miroslav; Baluška, František; Koshiba, Tomokazu

    2011-01-01

    To investigate the distribution of IAA (indole-3-acetic acid) and the IAA synthetic cells in maize coleoptiles, we established immunohistochemistry of IAA using an anti-IAA-C-monoclonal antibody. We first confirmed the specificity of the antibody by comparing the amounts of endogenous free and conjugated IAA to the IAA signal obtained from the IAA antibody. Depletion of endogenous IAA showed a corresponding decrease in immuno-signal intensity and negligible cross-reactivity against IAA-related compounds, including tryptophan, indole-3-acetamide, and conjugated-IAA was observed. Immunolocalization showed that the IAA signal was intense in the approximately 1 mm region and the outer epidermis at the approximately 0.5 mm region from the top of coleoptiles treated with 1-N-naphthylphthalamic acid. By contrast, the IAA immuno-signal in the outer epidermis almost disappeared after 5-methyl-tryptophan treatment. Immunogold labeling of IAA with an anti-IAA-N-polyclonal antibody in the outer-epidermal cells showed cytoplasmic localization of free-IAA, but none in cell walls or vacuoles. These findings indicated that IAA is synthesized in the 0–2.0 mm region of maize coleoptile tips from Trp, in which the outer-epidermal cells of the 0.5 mm tip are the most active IAA synthetic cells. PMID:22112455

  2. Interactions between indole-3-acetic acid (IAA) with a lectin from Canavalia maritima seeds reveal a new function for lectins in plant physiology.

    PubMed

    Delatorre, Plinio; Silva-Filho, José Caetano; Rocha, Bruno Anderson Matias; Santi-Gadelha, Tatiane; da Nóbrega, Raphael Batista; Gadelha, Carlos Alberto Almeida; do Nascimento, Kyria Santiago; Nagano, Celso Shiniti; Sampaio, Alexandre Holanda; Cavada, Benildo Sousa

    2013-09-01

    Indole-3-acetic acid (IAA) bound is considered a storage molecule and is inactive. However, some studies have proposed an additional possible regulatory mechanism based on the ability of lectins to form complexes with IAA. We report the first crystal structure of ConM in complex with IAA at 2.15 Å resolution. Based on a tetrameric model of the complex, we hypothesize how the lectin controls the availability of IAA during the early seedling stages, indicating a possible new physiological role for these proteins. A free indole group is also bound to the protein. The ConM interaction with different forms of IAA is a strategy to render the phytohormone unavailable to the cell. Thus, this new physiological role proposed for legume lectins might be a novel mechanism by which IAA levels are decreased in addition to the destruction and formation of new complexes in the later stages of seed germination. PMID:23727478

  3. Simultaneous detection and quantification of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) produced by rhizobacteria from l-tryptophan (Trp) using HPTLC.

    PubMed

    Goswami, Dweipayan; Thakker, Janki N; Dhandhukia, Pinakin C

    2015-03-01

    A simple, quick and reliable method is proposed for the detection and quantitation of indole-3-acetate (IAA) and indole-3-butyrate (IBA), an auxin phytohormone produced by rhizobacteria from l-tryptophan (Trp) metabolism using high performance thin-layer chromatography (HPTLC). Microbial auxin biosynthesis routes involve Trp as a precursor where other than IAA and IBA, products such as indole-3-pyruvate (IPA), indole-3-acetamide (IAM), tryptamine, indole-3-acetonitrile (IAN), indole-3-lactic acid (ILA) and indole-3-acetaldehyde (IAAld) are also produced. In traditional spectrophotometric method, Salkowski reagent develops color by reacting with indolic compounds. The color development is non-specific contributed by several Trp derivatives produced by rhizobacteria rather than IAA only. To overcome this limitation, HPTLC based protocol is developed to precisely detect and quantify IAA and IBA in the range of 100 to 1000ng per spot. This protocol is applicable to detect and quantify IAA and IBA from microbial samples ignoring other Trp derivatives. For microbial samples, the spectrophotometric method gives larger values as compared to HPTLC derived values which may be attributed by total indolic compounds reacting with Salkowski reagent rather than only IAA and/or IBA. PMID:25573587

  4. IAA-synthase, an enzyme complex from Arabidopsis thaliana catalyzing the formation of indole-3-acetic acid from (S)-tryptophan.

    PubMed

    Müller, A; Weiler, E W

    2000-08-01

    An enzyme complex was isolated from Arabidopsis thaliana that catalyzes the entire pathway of biosynthesis of the major plant growth hormone, indole-3-acetic acid (IAA), from (S)-tryptophan. The 160-180 kDa, soluble complex catalyzes a strictly O2-dependent reaction which requires no further added factors and is stereospecific for the substrate (S)-tryptophan (app. Km = 120 microM). H2(18)O labeling proved that both oxygen atoms of IAA were delivered via H2O. This, as well as immunological evidence for the presence of a nitrilase-like protein in the complex, suggests the reaction to proceed via the intermediate indole-3-acetonitrile. IAA-synthase forms a tight metabolite channel committed to IAA production and occurs in shoots, roots and cell cultures of A. thaliana. PMID:11030425

  5. Effects of Indole-3-Acetic Acid (IAA), a Plant Hormone, on the Ryegrass Yield and the Removal of Fluoranthene from Soil.

    PubMed

    Li, Weiming; Xu, Li; Wu, Jun; Ma, Lili; Liu, Manqiang; Jiao, Jiaguo; Li, Huixin; Hu, Feng

    2015-01-01

    A soil culture experiment was conducted to determine whether a plant hormone, indole-3-acetic acid (IAA), could influence fluoranthene (Flu) removal from soil. Four treatments were utilized: (i) unplanted soil (CK), (ii) soil planted with ryegrass (P), (iii) soil planted with ryegrass and treated with 0.24 mg kg(-1) IAA (P+0.24), (iv) soil planted with ryegrass and treated with 2.4 mg kg(-1) IAA (P+2.4). The Flu initial concentration was 200 mg kg(-1). After 3 months, the percentage of Flu removal and plant root biomass were significantly increased under the P+2.4 and the removal rate was 35.68%. The total Flu content in plants was higher than that in the other treatments. The Flu concentration was significantly increased in the shoots, but not significantly altered in the roots. The highest translocation factor was observed in the P+2.4. Increase in number of bacteria, actinomycetes and fungi were observed in the planted treatments, and the amount of fungi was significantly increased in P+2.4. Flu removal was related to the Flu in ryegrass, and was insignificantly correlated with the stimulation of soil microflora, which suggesting that IAA may work mainly on improving plant growth, the Flu uptake, and eventually leading to enhanced remediation of Flu polluted soil. PMID:25495932

  6. Indole-3-acetic acid (IAA) induced changes in oil content, fatty acid profiles and expression of four fatty acid biosynthetic genes in Chlorella vulgaris at early stationary growth phase.

    PubMed

    Jusoh, Malinna; Loh, Saw Hong; Chuah, Tse Seng; Aziz, Ahmad; Cha, Thye San

    2015-03-01

    Microalgae lipids and oils are potential candidates for renewable biodiesel. Many microalgae species accumulate a substantial amount of lipids and oils under environmental stresses. However, low growth rate under these adverse conditions account for the decrease in overall biomass productivity which directly influence the oil yield. This study was undertaken to investigate the effect of exogenously added auxin (indole-3-acetic acid; IAA) on the oil content, fatty acid compositions, and the expression of fatty acid biosynthetic genes in Chlorella vulgaris (UMT-M1). Auxin has been shown to regulate growth and metabolite production of several microalgae. Results showed that oil accumulation was highest on days after treatment (DAT)-2 with enriched levels of palmitic (C16:0) and stearic (C18:0) acids, while the linoleic (C18:2) and α-linolenic (C18:3n3) acids levels were markedly reduced by IAA. The elevated levels of saturated fatty acids (C16:0 and C18:0) were consistent with high expression of the β-ketoacyl ACP synthase I (KAS I) gene, while low expression of omega-6 fatty acid desaturase (ω-6 FAD) gene was consistent with low production of C18:2. However, the increment of stearoyl-ACP desaturase (SAD) gene expression upon IAA induction did not coincide with oleic acid (C18:1) production. The expression of omega-3 fatty acid desaturase (ω-3 FAD) gene showed a positive correlation with the synthesis of PUFA and C18:3n3. PMID:25583439

  7. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by etiolated and green corn tissues

    SciTech Connect

    Reinecke, D. )

    1989-04-01

    Etiolated corn tissues oxidase indole-3-acetic acid (IAA) to oxindole-3-acetic acid (OxIAA). This oxidation results in loss of auxin activity and may plant a role in regulating IAA-stimulated growth. The enzyme has been partially purified and characterized and shown to require O{sub 2}, and a heat-stable lipid-soluble corn factor which can be replaced by linolenic or linoleic acids in the oxidation of IAA. Corn oil was tested as a cofactor in the IAA oxidation reaction. Corn oil stimulated enzyme activity by 30% while trilinolein was inactive. The capacity of green tissue to oxidize IAA was examined by incubating leaf sections from 2 week old light-grown corn seedlings with {sup 14}C-IAA. OxIAA and IAA were separated from other IAA metabolites on a 3 ml anion exchange column. Of the IAA taken up by the sections, 13% was oxidized to OxIAA. This is the first evidence that green tissue of corn may also regulate IAA levels by oxidizing IAA to OxIAA.

  8. Indole-3-acetic acid (IAA) production trait, a useful screening to select endophytic and rhizosphere competent bacteria for rice growth promoting agents

    PubMed Central

    Etesami, Hassan; Alikhani, Hossein Ali; Hosseini, Hossein Mirseyed

    2015-01-01

    Plants select plant growth promoting rhizobacteria (PGPR) that are competitively fit to occupy compatible niches without causing pathological stress on them. However, when screening bacteria for plant growth promoting (PGP) agents, it is better to select bacteria for achieving the most promising isolates having suitable colonization and PGP traits. In most researches, it has been seen that following incubation, bacterial flora are taken at random from petri dishes for further study. However, this type of selection may remove some superior bacteria in terms of PGP traits and high colonization ability. Therefore, it is essential to study all the isolated bacteria in an economic way and select the best bacteria in terms of PGP traits and high colonization rate. A simple screening method to detect endophytic and rhizosphere bacteria, isolated from the plants in rotation with rice, for rice PGP agents based on a root colonization bioassay and a PGP trait is characterized. • Selected bacterial isolates based on their IAA producing trait have the potential for more PGP and colonization of rice plant. • IAA may be the first PGP trait for screening bacteria isolated from plant rotated with rice for rice PGP agents. • The screening procedure appears to be very effective and less time consuming. PMID:26150974

  9. Metabolic regulation of the plant hormone indole-3-acetic acid

    SciTech Connect

    Jerry D. Cohen

    2009-11-01

    The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research questions. A critical issue concerning the biosynthesis if IAA in plants is that redundant pathways for IAA biosynthesis exist in plants. We showed that these redundant pathways and their relative contribution to net IAA production are under both developmental and environmental control. We worked on three fundamental problems related to how plants get their IAA: 1) An in vitro biochemical approach was used to define the tryptophan dependent pathway to IAA using maize endosperm, where relatively large amounts of IAA are produced over a short developmental period. Both a stable isotope dilution and a protein MS approach were used to identify intermediates and enzymes in the reactions. 2) We developed an in vitro system for analysis of tryptophan-independent IAA biosynthesis in maize seedlings and we used a metabolite profiling approach to isolate intermediates in this reaction. 3) Arabidopsis contains a small family of genes that encode potential indolepyruvate decarboxylase enzymes. We cloned these genes and studied plants that are mutant in these genes and that over-express each member in the family in terms of the level and route of IAA biosynthesis. Together, these allowed further development of a comprehensive picture of the pathways and regulatory components that are involved in IAA homeostasis in higher plants.

  10. Identification of Indole-3-Acetic Acid in the Basidiomycete Schizophyllum commune 1

    PubMed Central

    Epstein, Ephraim; Miles, Philip G.

    1967-01-01

    Indole-3-acetic acid (IAA) was detected in the ether extracts of culture filtrates of indigotin-producing strains of the basidiomycete Schizophyllum commune. Several solvents, known to give distinctly different RF values for IAA, and 3 location reagents gave identical results with synthetic IAA and IAA found in the extract. Confirmation was obtained by the Avena straight growth test, split pea test, and ultraviolet absorption spectrum. PMID:16656596

  11. Molecular Cloning and Biochemical Characterization of Indole-3-acetic Acid Methyltransferase from Poplar (Populus trichocarpa)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Indole-3-acetic acid (IAA) is the most active endogenous auxin involved in various physiological processes in higher plants. Concentrations of IAA in plant tissues are regulated at multiple levels including de novo biosynthesis, degradation, and conjugation/deconjugation. In this paper, we report id...

  12. Determination of Endogenous Indole-3-Acetic Acid in Plagiochila arctica (Hepaticae) 1

    PubMed Central

    Law, David M.; Basile, Dominick V.; Basile, Margaret R.

    1985-01-01

    Endogenous indole-3-acetic acid (IAA) was found in axenically cultured gametophytes of the leafy liverwort, Plagiochila arctica Bryhn and Kaal., by high-performance liquid chromatography with electrochemical detection. Identification of the methylated auxin was confirmed by gas chromatography-mass spectrometry. Addition of 57 micromolar IAA to cultures increased relative production of ethylene. This is the first definitive (gas chromatography-mass spectrometry) demonstration of the natural occurrence of IAA in a bryophyte. PMID:16664164

  13. Indole-3-acetic acid: A widespread physiological code in interactions of fungi with other organisms

    PubMed Central

    Fu, Shih-Feng; Wei, Jyuan-Yu; Chen, Hung-Wei; Liu, Yen-Yu; Lu, Hsueh-Yu; Chou, Jui-Yu

    2015-01-01

    Plants as well as microorganisms, including bacteria and fungi, produce indole-3-acetic acid (IAA). IAA is the most common plant hormone of the auxin class and it regulates various aspects of plant growth and development. Thus, research is underway globally to exploit the potential for developing IAA-producing fungi for promoting plant growth and protection for sustainable agriculture. Phylogenetic evidence suggests that IAA biosynthesis evolved independently in bacteria, microalgae, fungi, and plants. Present studies show that IAA regulates the physiological response and gene expression in these microorganisms. The convergent evolution of IAA production leads to the hypothesis that natural selection might have favored IAA as a widespread physiological code in these microorganisms and their interactions. We summarize recent studies of IAA biosynthetic pathways and discuss the role of IAA in fungal ecology. PMID:26179718

  14. Auxin Biosynthesis: Are the Indole-3-Acetic Acid and Phenylacetic Acid Biosynthesis Pathways Mirror Images?

    PubMed

    Cook, Sam D; Nichols, David S; Smith, Jason; Chourey, Prem S; McAdam, Erin L; Quittenden, Laura; Ross, John J

    2016-06-01

    The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway. PMID:27208245

  15. Temperature-Sensitive Plant Cells with Shunted Indole-3-Acetic Acid Conjugation.

    PubMed Central

    Oetiker, J. H.; Aeschbacher, G.

    1997-01-01

    Cells of henbane (Hyoscyamus muticus L.) grow indefinitely in culture without exogenous auxin. Cells of its temperature-sensitive variant XIIB2 grow like the wild type at 26[deg]C but die rapidly at 33[deg]C unless auxin is added to the medium. Despite this temperature-sensitive auxin auxotrophy, XIIB2 produces wild-type amounts of indole-3-acetic acid (IAA). IAA is the predominant auxin and is important for plant growth and development. Since the IAA production of the variant is functional, we investigated whether the synthesis or degradation of IAA metabolites, possibly active auxins themselves, is altered. The IAA metabolites were IAA-aspartate (IAAsp) and IAA-glucose. The wild type converted IAA mainly to IAAsp, whereas the variant produced mainly IAA-glucose. Exogenous auxin corrected the shunted IAA metabolism of the variant. The half-life of labeled IAAsp in the variant was reduced 21-fold, but in the presence of exogenous auxin it was not different from the wild type. The temperature sensitivity of XIIB2 was also corrected by supplying IAAsp. Pulse-chase experiments revealed that henbane rapidly metabolizes IAAsp to compounds not identical to IAA. The data show that the variant XIIB2 is a useful tool to study the function of IAA conjugates to challenge the popular hypothesis that IAA conjugates are merely slow-release storage forms of IAA. PMID:12223777

  16. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    NASA Technical Reports Server (NTRS)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

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

    PubMed

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

    2001-02-01

    Biochemical characterization of recombinant gene products following a phylogenetic analysis of the UDP-glucosyltransferase (UGT) multigene family of Arabidopsis has identified one enzyme (UGT84B1) with high activity toward the plant hormone indole-3-acetic acid (IAA) and three related enzymes (UGT84B2, UGT75B1, and UGT75B2) with trace activities. The identity of the IAA conjugate has been confirmed to be 1-O-indole acetyl glucose ester. A sequence annotated as a UDP-glucose:IAA glucosyltransferase (IAA-UGT) in the Arabidopsis genome and expressed sequence tag data bases given its similarity to the maize iaglu gene sequence showed no activity toward IAA. This study describes the first biochemical analysis of a recombinant IAA-UGT and provides the foundation for future genetic approaches to understand the role of 1-O-indole acetyl glucose ester in Arabidopsis. PMID:11042207

  18. Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

    1986-01-01

    Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

  19. Translocation of radiolabeled indole-3-acetic acid and indole-3-acetyl-myo-inositol from kernel to shoot of Zea mays L

    NASA Technical Reports Server (NTRS)

    Chisnell, J. R.; Bandurski, R. S.

    1988-01-01

    Either 5-[3H]indole-3-acetic acid (IAA) or 5-[3H]indole-3-acetyl-myo-inositol was applied to the endosperm of kernels of dark-grown Zea mays seedlings. The distribution of total radioactivity, radiolabeled indole-3-acetic acid, and radiolabeled ester conjugated indole-3-acetic acid, in the shoots was then determined. Differences were found in the distribution and chemical form of the radiolabeled indole-3-acetic acid in the shoot depending upon whether 5-[3H]indole-3-acetic acid or 5-[3H]indole-3-acetyl-myo-inositol was applied to the endosperm. We demonstrated that indole-3-acetyl-myo-inositol applied to the endosperm provides both free and ester conjugated indole-3-acetic acid to the mesocotyl and coleoptile. Free indole-3-acetic acid applied to the endosperm supplies some of the indole-3-acetic acid in the mesocotyl but essentially no indole-3-acetic acid to the coleoptile or primary leaves. It is concluded that free IAA from the endosperm is not a source of IAA for the coleoptile. Neither radioactive indole-3-acetyl-myo-inositol nor IAA accumulates in the tip of the coleoptile or the mesocotyl node and thus these studies do not explain how the coleoptile tip controls the amount of IAA in the shoot.

  20. UGT74D1 catalyzes the glucosylation of 2-oxindole-3-acetic acid in the auxin metabolic pathway in Arabidopsis.

    PubMed

    Tanaka, Keita; Hayashi, Ken-ichiro; Natsume, Masahiro; Kamiya, Yuji; Sakakibara, Hitoshi; Kawaide, Hiroshi; Kasahara, Hiroyuki

    2014-01-01

    IAA is a naturally occurring auxin that plays a crucial role in the regulation of plant growth and development. The endogenous concentration of IAA is spatiotemporally regulated by biosynthesis, transport and its inactivation in plants. Previous studies have shown that the metabolism of IAA to 2-oxindole-3-acetic acid (OxIAA) and OxIAA-glucoside (OxIAA-Glc) may play an important role in IAA homeostasis, but the genes involved in this metabolic pathway are still unknown. In this study, we show that UGT74D1 catalyzes the glucosylation of OxIAA in Arabidopsis. By screening yeasts transformed with Arabidopsis UDP-glycosyltransferase (UGT) genes, we found that OxIAA-Glc accumulates in the culture media of yeasts expressing UGT74D1 in the presence of OxIAA. Further, we showed that UGT74D1 expressed in Escherichia coli converts OxIAA to OxIAA-Glc. The endogenous concentration of OxIAA-Glc decreased by 85% while that of OxIAA increased 2.5-fold in ugt74d1-deficient mutants, indicating the major role of UGT74D1 in OxIAA metabolism. Moreover, the induction of UGT74D1 markedly increased the level of OxIAA-Glc and loss of root gravitropism. These results indicate that UGT74D1 catalyzes a committed step in the OxIAA-dependent IAA metabolic pathway in Arabidopsis. PMID:24285754

  1. Modulation of endogenous indole-3-acetic acid biosynthesis in bacteroids within Medicago sativa nodules.

    PubMed

    Bianco, C; Senatore, B; Arbucci, S; Pieraccini, G; Defez, R

    2014-07-01

    To evaluate the dose-response effects of endogenous indole-3-acetic acid (IAA) on Medicago plant growth and dry weight production, we increased the synthesis of IAA in both free-living and symbiosis-stage rhizobial bacteroids during Rhizobium-legume symbiosis. For this purpose, site-directed mutagenesis was applied to modify an 85-bp promoter sequence, driving the expression of iaaM and tms2 genes for IAA biosynthesis. A positive correlation was found between the higher expression of IAA biosynthetic genes in free-living bacteria and the increased production of IAA under both free-living and symbiotic conditions. Plants nodulated by RD65 and RD66 strains, synthetizing the highest IAA concentration, showed a significant (up to 73%) increase in the shoot fresh weight and upregulation of nitrogenase gene, nifH, compared to plants nodulated by the wild-type strain. When these plants were analyzed by confocal microscopy, using an anti-IAA antibody, the strongest signal was observed in bacteroids of Medicago sativa RD66 (Ms-RD66) plants, even when they were located in the senescent nodule zone. We show here a simple system to modulate endogenous IAA biosynthesis in bacteria nodulating legumes suitable to investigate which is the maximum level of IAA biosynthesis, resulting in the maximal increase of plant growth. PMID:24814784

  2. Biosynthesis of the halogenated auxin, 4-chloroindole-3-acetic acid.

    PubMed

    Tivendale, Nathan D; Davidson, Sandra E; Davies, Noel W; Smith, Jason A; Dalmais, Marion; Bendahmane, Abdelhafid I; Quittenden, Laura J; Sutton, Lily; Bala, Raj K; Le Signor, Christine; Thompson, Richard; Horne, James; Reid, James B; Ross, John J

    2012-07-01

    Seeds of several agriculturally important legumes are rich sources of the only halogenated plant hormone, 4-chloroindole-3-acetic acid. However, the biosynthesis of this auxin is poorly understood. Here, we show that in pea (Pisum sativum) seeds, 4-chloroindole-3-acetic acid is synthesized via the novel intermediate 4-chloroindole-3-pyruvic acid, which is produced from 4-chlorotryptophan by two aminotransferases, TRYPTOPHAN AMINOTRANSFERASE RELATED1 and TRYPTOPHAN AMINOTRANSFERASE RELATED2. We characterize a tar2 mutant, obtained by Targeting Induced Local Lesions in Genomes, the seeds of which contain dramatically reduced 4-chloroindole-3-acetic acid levels as they mature. We also show that the widespread auxin, indole-3-acetic acid, is synthesized by a parallel pathway in pea. PMID:22573801

  3. Indole-3-acetic acid in Fusarium graminearum: Identification of biosynthetic pathways and characterization of physiological effects.

    PubMed

    Luo, Kun; Rocheleau, Hélène; Qi, Peng-Fei; Zheng, You-Liang; Zhao, Hui-Yan; Ouellet, Thérèse

    2016-09-01

    Fusarium graminearum is a devastating pathogenic fungus causing fusarium head blight (FHB) of wheat. This fungus can produce indole-3-acetic acid (IAA) and a very large amount of IAA accumulates in wheat head tissues during the first few days of infection by F. graminearum. Using liquid culture conditions, we have determined that F. graminearum can use tryptamine (TAM) and indole-3-acetonitrile (IAN) as biosynthetic intermediates to produce IAA. It is the first time that F. graminearum is shown to use the l-tryptophan-dependent TAM and IAN pathways rather than the indole-3-acetamide or indole-3-pyruvic acid pathways to produce IAA. Our experiments also showed that exogenous IAA was metabolized by F. graminearum. Exogenous IAA, TAM, and IAN inhibited mycelial growth; IAA and IAN also affected the hyphae branching pattern and delayed macroconidium germination. IAA and TAM had a small positive effect on the production of the mycotoxin 15-ADON while IAN inhibited its production. Our results showed that IAA and biosynthetic intermediates had a significant effect on F. graminearum physiology and suggested a new area of exploration for fungicidal compounds. PMID:27567719

  4. Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S.

    1984-01-01

    Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.

  5. Indole-3-acetic acid biosynthetic pathways in the basidiomycetous yeast Rhodosporidium paludigenum.

    PubMed

    Nutaratat, Pumin; Srisuk, Nantana; Arunrattiyakorn, Panarat; Limtong, Savitree

    2016-07-01

    Microorganisms produce plant growth regulators, such as auxins, cytokinins and gibberellins, to promote plant growth. Auxins are a group of compounds with an indole ring that have a positive effect on plant growth. Indole-3-acetic acid (IAA) is a plant growth hormone classified as an indole derivative of the auxin family. IAA biosynthesis pathways have been reported and widely studied in several groups of bacteria. Only a few studies on IAA biosynthesis pathways have been conducted in yeast. This study aimed to investigate IAA biosynthesis pathways in a basidiomycetous yeast (Rhodosporidium paludigenum DMKU-RP301). Investigations were performed both with and without a tryptophan supplement. Indole compound intermediates were detected by gas chromatography-mass spectrometry. Indole-3-lactic acid and indole-3-ethanol were found as a result of the enzymatic reduction of indole-3-pyruvic acid and indole-3-acetaldehyde, in IAA biosynthesis via an indole-3-pyruvic acid pathway. In addition, we also found indole-3-pyruvic acid in culture supernatants determined by high-performance liquid chromatography. Identification of tryptophan aminotransferase activity supports indole-3-pyruvic acid-routed IAA biosynthesis in R. paludigenum DMKU-RP301. We hence concluded that R. paludigenum DMKU-RP301 produces IAA through an indole-3-pyruvic acid pathway. PMID:26899734

  6. New insights into the role of indole-3-acetic acid in the virulence of Pseudomonas savastanoi pv. savastanoi.

    PubMed

    Aragón, Isabel M; Pérez-Martínez, Isabel; Moreno-Pérez, Alba; Cerezo, Miguel; Ramos, Cayo

    2014-07-01

    Indole-3-acetic acid (IAA) is a widespread phytohormone among plant-associated bacteria, including the tumour-inducing pathogen of woody hosts, Pseudomonas savastanoi pv. savastanoi. A phylogenetic analysis of the iaaM/iaaH operon, which is involved in the biosynthesis of IAA, showed that one of the two operons encoded by Pseudomonas savastanoi pv. savastanoi NCPPB 3335, iaaM-1/iaaH-1, is horizontally transferred among bacteria belonging to the Pseudomonas syringae complex. We also show that biosynthesis of the phytohormone, virulence and full fitness of this olive pathogen depend only on the functionality of the iaaM-1/iaaH-1 operon. In contrast, the iaaM-2/iaaH-2 operon, which carries a 22-nt insertion in the iaaM-2 gene, does not contribute to the production of IAA by this bacterium. A residual amount of IAA was detected in the culture supernatants of a double mutant affected in both iaaM/iaaH operons, suggesting that a different pathway might also contribute to the total pool of the phytohormone produced by this pathogen. Additionally, we show that exogenously added IAA negatively and positively regulates the expression of genes related to the type III and type VI secretion systems, respectively. Together, these results suggest a role of IAA as a signalling molecule in this pathogen. PMID:24606017

  7. Transport of the two natural auxins, indole-3-butyric acid and indole-3-acetic acid, in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Rashotte, Aaron M.; Poupart, Julie; Waddell, Candace S.; Muday, Gloria K.; Brown, C. S. (Principal Investigator)

    2003-01-01

    Polar transport of the natural auxin indole-3-acetic acid (IAA) is important in a number of plant developmental processes. However, few studies have investigated the polar transport of other endogenous auxins, such as indole-3-butyric acid (IBA), in Arabidopsis. This study details the similarities and differences between IBA and IAA transport in several tissues of Arabidopsis. In the inflorescence axis, no significant IBA movement was detected, whereas IAA is transported in a basipetal direction from the meristem tip. In young seedlings, both IBA and IAA were transported only in a basipetal direction in the hypocotyl. In roots, both auxins moved in two distinct polarities and in specific tissues. The kinetics of IBA and IAA transport appear similar, with transport rates of 8 to 10 mm per hour. In addition, IBA transport, like IAA transport, is saturable at high concentrations of auxin, suggesting that IBA transport is protein mediated. Interestingly, IAA efflux inhibitors and mutations in genes encoding putative IAA transport proteins reduce IAA transport but do not alter IBA movement, suggesting that different auxin transport protein complexes are likely to mediate IBA and IAA transport. Finally, the physiological effects of IBA and IAA on hypocotyl elongation under several light conditions were examined and analyzed in the context of the differences in IBA and IAA transport. Together, these results present a detailed picture of IBA transport and provide the basis for a better understanding of the transport of these two endogenous auxins.

  8. A mutation affecting the synthesis of 4-chloroindole-3-acetic acid.

    PubMed

    Ross, John J; Tivendale, Nathan D; Davidson, Sandra E; Reid, James B; Davies, Noel W; Quittenden, Laura J; Smith, Jason A

    2012-12-01

    Traditionally, schemes depicting auxin biosynthesis in plants have been notoriously complex. They have involved up to four possible pathways by which the amino acid tryptophan might be converted to the main active auxin, indole-3-acetic acid (IAA), while another pathway was suggested to bypass tryptophan altogether. It was also postulated that different plants use different pathways, further adding to the complexity. In 2011, however, it was suggested that one of the four tryptophan-dependent pathways, via indole-3-pyruvic acid (IPyA), is the main pathway in Arabidopsis thaliana, although concurrent operation of one or more other pathways has not been excluded. We recently showed that, for seeds of Pisum sativum (pea), it is possible to go one step further. Our new evidence indicates that the IPyA pathway is the only tryptophan-dependent IAA synthesis pathway operating in pea seeds. We also demonstrated that the main auxin in developing pea seeds, 4-chloroindole-3-acetic acid (4-Cl-IAA), which accumulates to levels far exceeding those of IAA, is synthesized via a chlorinated version of the IPyA pathway. PMID:23073010

  9. Auxin Biosynthesis: Are the Indole-3-Acetic Acid and Phenylacetic Acid Biosynthesis Pathways Mirror Images?1[OPEN

    PubMed Central

    Nichols, David S.; Smith, Jason; Chourey, Prem S.; McAdam, Erin L.; Quittenden, Laura

    2016-01-01

    The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA. However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway. PMID:27208245

  10. Endohyphal Bacterium Enhances Production of Indole-3-Acetic Acid by a Foliar Fungal Endophyte

    PubMed Central

    Hoffman, Michele T.; Gunatilaka, Malkanthi K.; Wijeratne, Kithsiri; Gunatilaka, Leslie; Arnold, A. Elizabeth

    2013-01-01

    Numerous plant pathogens, rhizosphere symbionts, and endophytic bacteria and yeasts produce the important phytohormone indole-3-acetic acid (IAA), often with profound effects on host plants. However, to date IAA production has not been documented among foliar endophytes -- the diverse guild of primarily filamentous Ascomycota that live within healthy, above-ground tissues of all plant species studied thus far. Recently bacteria that live within hyphae of endophytes (endohyphal bacteria) have been detected, but their effects have not been studied previously. Here we show not only that IAA is produced in vitro by a foliar endophyte (here identified as Pestalotiopsis aff. neglecta, Xylariales), but that IAA production is enhanced significantly when the endophyte hosts an endohyphal bacterium (here identified as Luteibacter sp., Xanthomonadales). Both the endophyte and the endophyte/bacterium complex appear to rely on an L-tryptophan dependent pathway for IAA synthesis. The bacterium can be isolated from the fungus when the symbiotic complex is cultivated at 36°C. In pure culture the bacterium does not produce IAA. Culture filtrate from the endophyte-bacterium complex significantly enhances growth of tomato in vitro relative to controls and to filtrate from the endophyte alone. Together these results speak to a facultative symbiosis between an endophyte and endohyphal bacterium that strongly influences IAA production, providing a new framework in which to explore endophyte-plant interactions. PMID:24086270

  11. Production of indole-3-acetic acid by the cyanobacterium Arthrospira platensis strain MMG-9.

    PubMed

    Ahmed, Mehboob; Stal, Lucas; Hasnain, Shahida

    2010-09-01

    The filamentous cyanobacterium Arthrospira platensis strain MMG-9 was isolated from a rice field. The ability of this strain to synthesize the bioactive compound indole-3-acetic acid (IAA) was demonstrated. IAA was extracted from the culture A. platensis strain MMG-9 and its identity was confirmed by thin layer chromatography (TLC) as well as by high performance liquid chromatography (HPLC). The IAA precursor L-tryptophan was required for IAA biosynthesis. Released IAA increased with the increase of the initial concentration of L-tryptophan in the medium and with the incubation time. A. platensis strain MMG-9 accumulates more IAA than it released it into the medium. The bioactivity of the secreted IAA was shown by its effect on the formation of roots by Pisum sativum. There was a significant positive effect of the supernatant of cultures of A. platensis strain MMG-9 on the number of lateral roots of P. sativum while a negative effect on root length was observed. PMID:20890089

  12. Hydrolysis of Indole-3-Acetic Acid Esters Exposed to Mild Alkaline Conditions 1

    PubMed Central

    Baldi, Bruce G.; Maher, Barbara R.; Cohen, Jerry D.

    1989-01-01

    Ester conjugates of indole-3-acetic acid are hydrolyzed easily in basic solutions; however, quantitative data have not been available on the relationship between pH and rate of hydrolysis of the known ester conjugates. The use of basic conditions during extraction or purification of IAA by several laboratories suggested that a more systematic analysis of this process was needed. In this report we present data indicating: (a) that measurable hydrolysis of IAA-glucose (from standard solutions) and IAA-esters (from maize kernel extracts) occurs with only a few hours of treatment at pH 9 or above; (b) that the lability of some ester conjugates is even greater than that of IAA-glucose; and (c) that ester hydrolysis of standard compounds, IAA-glucose and IAA-p-nitrophenol, occurs in the `three phase extraction system' proposed by Liu and Tillberg ([1983] Physiol Plant 57: 441-447). These data indicate that the potential for problems with inadvertent hydrolysis of ester conjugates of IAA exists even at moderate pH values and in the multiphase system where exposure to basic conditions was thought to be limited. PMID:16667049

  13. Cloning and biochemical characterization of indole-3-acetic acid-amino acid synthetase PsGH3 from pea.

    PubMed

    Ostrowski, Maciej; Mierek-Adamska, Agnieszka; Porowińska, Dorota; Goc, Anna; Jakubowska, Anna

    2016-10-01

    Phytohormone conjugation is one of the mechanisms that maintains a proper hormonal homeostasis and that is necessary for the realization of physiological responses. Gretchen Hagen 3 (GH3) acyl acid amido synthetases convert indole-3-acetic acid (IAA) to IAA-amino acid conjugates by ATP-dependent reactions. IAA-aspartate (IAA-Asp) exists as a predominant amide conjugate of auxin in pea tissues and acts as an intermediate during IAA catabolism. Here we report a novel recombinant indole-3-acetic acid-amido synthetase in Pisum sativum. In silico analysis shows that amino acid sequence of PsGH3 has the highest homology to Medicago truncatula GH3.3. The recombinant His-tag-PsGH3 fusion protein has been obtained in E. coli cells and is a soluble monomeric polypeptide with molecular mass of 69.18 kDa. The PsGH3 was purified using Ni(2+)-affinity chromatography and native PAGE. Kinetic analysis indicates that the enzyme strongly prefers IAA and L-aspartate as substrates for conjugation revealing Km(ATP) = 0.49 mM, Km(L-Asp) = 2.2 mM, and Km(IAA) = 0.28 mM. Diadenosine pentaphosphate (Ap5A) competes with ATP for catalytic site and diminishes the PsGH3 affinity toward ATP approximately 1.11-fold indicating Ki = 8.5 μM. L-Tryptophan acts as an inhibitor of IAA-amido synthesizing activity by competition with L-aspartate. Inorganic pyrophosphatase (PPase) hydrolyzing pyrophosphate to two phosphate ions, potentiates IAA-Asp synthetase activity of PsGH3. Our results demonstrate that PsGH3 is a novel enzyme that is involved in auxin metabolism in pea seeds. PMID:27235647

  14. Indole-3-acetic acid protein conjugates: novel players in auxin homeostasis.

    PubMed

    Seidel, C; Walz, A; Park, S; Cohen, J D; Ludwig-Müller, J

    2006-05-01

    Indole-3-acetic acid (IAA) is found in plants in both free and conjugated forms. Within the group of conjugated IAA there is a unique class of proteins and peptides where IAA is attached directly to the polypeptide structure as a prosthetic group. The first gene, IAP1, encoding for a protein with IAA as a prosthetic group, was cloned from bean (Phaseolus vulgaris). It was shown that the expression of IAP1 as a major IAA modified protein in bean seed (PvIAP1) was correlated to a developmental period of rapid growth during seed development. Moreover, this protein underwent rapid degradation during germination. Since further molecular analysis was difficult in bean, the IAP1 gene was transformed into Arabidopsis thaliana and Medicago truncatula. Expression of the bean IAP1 gene in both plant species under the control of its native promoter targeted protein expression to the seeds. In Arabidopsis no IAA was found to be attached to PvIAP1. These results show that there is specificity to protein modification by IAA and suggests that protein conjugation may be catalyzed by species specific enzymes. Furthermore, subcellular localization showed that in Arabidopsis PvIAP1 was predominantly associated with the microsomal fraction. In addition, a related protein and several smaller peptides that are conjugated to IAA were identified in Arabidopsis. Further research on this novel class of proteins from Arabidopsis will both advance our knowledge of IAA proteins and explore aspects of auxin homeostasis that were not fully revealed by studies of free IAA and lower molecular weight conjugates. PMID:16807826

  15. Preparation of a novel colorimetric luminescence sensor strip for the detection of indole-3-acetic acid.

    PubMed

    Liu, Yan; Dong, Haitao; Zhang, Wenzhu; Ye, Zhiqiang; Wang, Guilan; Yuan, Jingli

    2010-06-15

    A novel colorimetric luminescence sensor strip for the detection of indole-3-acetic acid (IAA) has been fabricated by using green emissive quantum dots of cadmium telluride (CdTe QDs) as a background layer and a red emissive europium chelate, [4'-(9-anthryl)-2,2':6',2''-terpyridine-6,6''-diyl]bis(methylenenitrilo) tetrakis(acetate)-Eu(3+) (ATTA-Eu(3+)), as a specific sensing layer coated on the surface of glass slide, respectively. The luminescence response of the sensor strip is given by the dramatic changes in emission colors from green to red at different IAA concentrations. This approach provides a simple, rapid, sensitive and accurate method for the detection of IAA without using any special scientific instruments. PMID:20353890

  16. An in vitro system from maize seedlings for tryptophan-independent indole-3-acetic acid biosynthesis

    SciTech Connect

    Oestin, A.; Ilic, N.; Cohen, J.D.

    1999-01-01

    The enzymatic synthesis of indole-3-acetic acid (IAA) from indole by an in vitro preparation from maize (Zea mays L.) that does not use tryptophan (Trp) as an intermediate is described. Light-grown seedlings of normal maize and the maize mutant orange pericarp were shown to contain the necessary enzymes to convert [{sup 14}C]indole to IAA. The reaction was not inhibited by unlabeled Trp and neither [{sup 14}C]Trp nor [{sup 14}C]serine substituted for [{sup 14}C]indole in this in vitro system. The reaction had a pH optimum greater than 8.0, required a reducing environment, and had an oxidation potential near that of ascorbate. The results obtained with this in vitro enzyme preparation provide strong, additional evidence for the presence of a Trp-independent IAA biosynthesis pathway in plants.

  17. Rate Motifs Tune Auxin/Indole-3-Acetic Acid Degradation Dynamics1[OPEN

    PubMed Central

    Moss, Britney L.; Mao, Haibin; Guseman, Jessica M.; Hinds, Thomas R.; Hellmuth, Antje; Kovenock, Marlies; Noorassa, Anisa; Lanctot, Amy; Villalobos, Luz Irina A. Calderón; Zheng, Ning; Nemhauser, Jennifer L.

    2015-01-01

    Ubiquitin-mediated protein degradation is a common feature in diverse plant cell signaling pathways; however, the factors that control the dynamics of regulated protein turnover are largely unknown. One of the best-characterized families of E3 ubiquitin ligases facilitates ubiquitination of auxin (aux)/indole-3-acetic acid (IAA) repressor proteins in the presence of auxin. Rates of auxin-induced degradation vary widely within the Aux/IAA family, and sequences outside of the characterized degron (the minimum region required for auxin-induced degradation) can accelerate or decelerate degradation. We have used synthetic auxin degradation assays in yeast (Saccharomyces cerevisiae) and in plants to characterize motifs flanking the degron that contribute to tuning the dynamics of Aux/IAA degradation. The presence of these rate motifs is conserved in phylogenetically distant members of the Arabidopsis (Arabidopsis thaliana) Aux/IAA family, as well as in their putative Brassica rapa orthologs. We found that rate motifs can act by enhancing interaction between repressors and the E3, but that this is not the only mechanism of action. Phenotypes of transgenic plants expressing a deletion in a rate motif in IAA28 resembled plants expressing degron mutations, underscoring the functional relevance of Aux/IAA degradation dynamics in regulating auxin responses. PMID:26149575

  18. Rate Motifs Tune Auxin/Indole-3-Acetic Acid Degradation Dynamics.

    PubMed

    Moss, Britney L; Mao, Haibin; Guseman, Jessica M; Hinds, Thomas R; Hellmuth, Antje; Kovenock, Marlies; Noorassa, Anisa; Lanctot, Amy; Villalobos, Luz Irina A Calderón; Zheng, Ning; Nemhauser, Jennifer L

    2015-09-01

    Ubiquitin-mediated protein degradation is a common feature in diverse plant cell signaling pathways; however, the factors that control the dynamics of regulated protein turnover are largely unknown. One of the best-characterized families of E3 ubiquitin ligases facilitates ubiquitination of auxin (aux)/indole-3-acetic acid (IAA) repressor proteins in the presence of auxin. Rates of auxin-induced degradation vary widely within the Aux/IAA family, and sequences outside of the characterized degron (the minimum region required for auxin-induced degradation) can accelerate or decelerate degradation. We have used synthetic auxin degradation assays in yeast (Saccharomyces cerevisiae) and in plants to characterize motifs flanking the degron that contribute to tuning the dynamics of Aux/IAA degradation. The presence of these rate motifs is conserved in phylogenetically distant members of the Arabidopsis (Arabidopsis thaliana) Aux/IAA family, as well as in their putative Brassica rapa orthologs. We found that rate motifs can act by enhancing interaction between repressors and the E3, but that this is not the only mechanism of action. Phenotypes of transgenic plants expressing a deletion in a rate motif in IAA28 resembled plants expressing degron mutations, underscoring the functional relevance of Aux/IAA degradation dynamics in regulating auxin responses. PMID:26149575

  19. Effects of Indole-3-Acetic Acid on the Transcriptional Activities and Stress Tolerance of Bradyrhizobium japonicum

    PubMed Central

    Donati, Andrew J.; Lee, Hae-In; Leveau, Johan H. J.; Chang, Woo-Suk

    2013-01-01

    A genome-wide transcriptional profile of Bradyrhizobium japonicum, the nitrogen-fixing endosymbiont of the soybean plant, revealed differential expression of approximately 15% of the genome after a 1 mM treatment with the phytohormone indole-3-acetic acid (IAA). A total of 1,323 genes were differentially expressed (619 up-regulated and 704 down-regulated) at a two-fold cut off with q value ≤ 0.05. General stress response genes were induced, such as those involved in response to heat, cold, oxidative, osmotic, and desiccation stresses and in exopolysaccharide (EPS) biosynthesis. This suggests that IAA is effective in activating a generalized stress response in B. japonicum. The transcriptional data were corroborated by the finding that stress tolerance of B. japonicum in cell viability assays was enhanced when pre-treated with 1 mM IAA compared to controls. The IAA treatment also stimulated biofilm formation and EPS production by B. japonicum, especially acidic sugar components in the total EPS. The IAA pre-treatment did not influence the nodulation ability of B. japonicum. The data provide a comprehensive overview of the potential transcriptional responses of the symbiotic bacterium when exposed to the ubiquitous hormone of its plant host. PMID:24098533

  20. Identification of enzyme activity that conjugates indole-3-acetic acid to aspartate in immature seeds of pea (Pisum sativum).

    PubMed

    Ostrowski, Maciej; Jakubowska, Anna

    2008-01-01

    This study describes the first identification of plant enzyme activity catalyzing the conjugation of indole-3-acetic acid to amino acids. Enzymatic synthesis of indole-3-acetylaspartate (IAA-Asp) by a crude enzyme preparation from immature seeds of pea (Pisum sativum) was observed. The reaction yielded a product with the same Rf as IAA-Asp standard after thin layer chromatography. The identity of IAA-Asp was verified by HPLC analysis. IAA-Asp formation was dependent on ATP and Mg2+, and was linear during a 60 min period. The enzyme preparation obtained after poly(ethylene glycol) 6000 fractionation showed optimum activity at pH 8.0, and the temperature optimum for IAA-Asp synthesis was 30 degrees C. PMID:17920159

  1. Effects of indole-3-acetic acid on Botrytis cinerea isolates obtained from potted plants.

    PubMed

    Martínez, J A; Valdés, R; Gómez-Bellot, M J; Bañón, S

    2011-01-01

    We study the growth of different isolates of Botrytis cinerea collected from potted plants which were affected by Botrytis blight in southern Spain during recent years. These isolates, which show widely phenotypic differences when grown in vitro, are differentially affected by growth temperature, gibberellic acid applications and paclobutrazol, an efficient plant growth retardant and fungicide at the same time. In this work, we have evaluated the effect of the auxin indole-3-acetic acid (IAA) dose (0, 1, 10, and 100 mg/plate) on the growth of the collection of B. cinerea isolates obtained from the following potted plants: Cyclamen persicum, Hydrangea macrophylla, Lantona camara, and Lonicera japonica. B. cinerea produces indolacetic acid, but so far the precise biosynthetic pathway and some effects on this fungal species are still unclear, although recent studies have revealed an antifungal activity of IAA on several fungi, including B. cinerea isolated from harvested fruits. Mycelial growth curves and growth rates assessed from difference in colony areas during the both linear and deceleration phase, conidiation (measured as time of appearance), conidia length (microm), and sclerotia production (number/plate) were evaluated in the isolates, which were grown at 26 degrees C on Petri dishes containing potato dextrose agar for up to 35 days. Mycelial growth curves fitted a typical kinetic equation of fungi grown on solid media. B. cinerea isolates showed a high degree of variability in their growth kinetics, depending on the isolate and auxin dose. This plant growth substance delayed mycelial growth during the linear phase in an isolate-dependent manner, thus isolates from C. persicum, H. macrophylla and L. camara were more affected by IAA than L. japonica. On the other hand, 100 mg of IAA was the critical dose to significantly reduce the growth rate in all isolates and to promote brown-striped hyphae development, especially in isolate from C. persicum. 10 and 100 mg

  2. Simultaneous determination of 2-naphthoxyacetic acid and indole-3-acetic acid by first derivation synchronous fluorescence spectroscopy.

    PubMed

    Liu, Xiangxiang; Wan, Yiqun

    2013-07-01

    A simple, rapid, sensitive and selective method for simultaneously determining 2-naphthoxyacetic acid (BNOA) and Indole-3-Acetic Acid (IAA) in mixtures has been developed using derivation synchronous fluorescence spectroscopy based on their synchronous fluorescence. The synchronous fluorescence spectra were obtained with Δλ=100 nm in a pH 8.5 NaH2PO4-NaOH buffer solution, and the detected wavelengths of quantitative analysis were set at 239 nm for BNOA and 293 nm for IAA respectively. The over lapped fluorescence spectra were well separated by the synchronous derivative method. Under optimized conditions, the limits of detection (LOD) were 0.003 μg/mL for BNOA and 0.012 μg/mL for IAA. This method is simple and expeditious, and it has been successfully applied to the determination of 2-naphthoxyacetic acid and indole-3-acetic acid in fruit juice samples with satisfactory results. The samples were only filtrated through a 0.45 μm membrane filter, which was free from the tedious separation procedures. The obtaining recoveries were in the range of 83.88-87.43% for BNOA and 80.76-86.68% for IAA, and the relative standard deviations were all less than 5.0%. Statistical comparison of the results with high performance liquid chromatography Mass Spectrometry (HPLC-MS) method revealed good agreement and proved that there were no significant difference in the accuracy and precision between these two methods. PMID:23651742

  3. Simultaneous determination of 2-naphthoxyacetic acid and indole-3-acetic acid by first derivation synchronous fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Xiangxiang; Wan, Yiqun

    2013-07-01

    A simple, rapid, sensitive and selective method for simultaneously determining 2-naphthoxyacetic acid (BNOA) and Indole-3-Acetic Acid (IAA) in mixtures has been developed using derivation synchronous fluorescence spectroscopy based on their synchronous fluorescence. The synchronous fluorescence spectra were obtained with Δλ = 100 nm in a pH 8.5 NaH2PO4-NaOH buffer solution, and the detected wavelengths of quantitative analysis were set at 239 nm for BNOA and 293 nm for IAA respectively. The over lapped fluorescence spectra were well separated by the synchronous derivative method. Under optimized conditions, the limits of detection (LOD) were 0.003 μg/mL for BNOA and 0.012 μg/mL for IAA. This method is simple and expeditious, and it has been successfully applied to the determination of 2-naphthoxyacetic acid and indole-3-acetic acid in fruit juice samples with satisfactory results. The samples were only filtrated through a 0.45 μm membrane filter, which was free from the tedious separation procedures. The obtaining recoveries were in the range of 83.88-87.43% for BNOA and 80.76-86.68% for IAA, and the relative standard deviations were all less than 5.0%. Statistical comparison of the results with high performance liquid chromatography Mass Spectrometry (HPLC-MS) method revealed good agreement and proved that there were no significant difference in the accuracy and precision between these two methods.

  4. Occurrence and metabolism of 7-hydroxy-2-indolinone-3-acetic acid in Zea mays

    NASA Technical Reports Server (NTRS)

    Lewer, P.; Bandurski, R. S.

    1987-01-01

    7-Hydroxy-2-indolinone-3-acetic acid was identified as a catabolite of indole-3-acetic acid in germinating kernels of Zea mays and found to be present in amounts of ca 3.1 nmol/kernel. 7-Hydroxy-2-indolinone-3-acetic acid was shown to be a biosynthetic intermediate between 2-indolinone-3-acetic acid and 7-hydroxy-2-indolinone-3-acetic acid-7'-O-glucoside in both kernels and roots of Zea mays. Further metabolism of 7-hydroxy-2-[5-3H]-indolinone-3-acetic acid-7'-O-glucoside occurred to yield tritiated water plus, as yet, uncharacterized products.

  5. Dynamics and control of phloem loading of indole-3-acetic acid in seedling cotyledons of Ricinus communis

    PubMed Central

    Tamas, Imre A.; Davies, Peter J.

    2016-01-01

    During seed germination, sugars and auxin are produced from stored precursors or conjugates respectively, and transported to the seedling axis. To elucidate the mode of travel of indole-3-acetic acid (IAA) into the phloem, a solution of [3H]IAA, together with [14C]sucrose, was injected into the endosperm cavity harboring the cotyledons of germinating seedlings of Ricinus communis. Phloem exudate from the cut hypocotyl was collected and the radioactivity recorded. Sucrose loading into the phloem was inhibited at higher IAA levels, and the rate of filling of the transient pool(s) was reduced by IAA. IAA was detected within 10min, with the concentration increasing over 30min and reaching a steady-state by 60min. The kinetics indicated that phloem loading of IAA involving both an active, carrier-based, and a passive, diffusion-based component, with IAA traveling along a pathway containing an intermediary pool, possibly the protoplasts of mesophyll cells. Phloem loading of IAA was altered by sucrose, K+, and a range of non-specific and IAA-specific analogs and inhibitors in a manner that showed that IAA moves into the phloem from the extra cotyledonary solution by multiple pathways, with a carrier-mediated pathway playing a principal role. PMID:27371947

  6. Dynamics and control of phloem loading of indole-3-acetic acid in seedling cotyledons of Ricinus communis.

    PubMed

    Tamas, Imre A; Davies, Peter J

    2016-08-01

    During seed germination, sugars and auxin are produced from stored precursors or conjugates respectively, and transported to the seedling axis. To elucidate the mode of travel of indole-3-acetic acid (IAA) into the phloem, a solution of [(3)H]IAA, together with [(14)C]sucrose, was injected into the endosperm cavity harboring the cotyledons of germinating seedlings of Ricinus communis Phloem exudate from the cut hypocotyl was collected and the radioactivity recorded. Sucrose loading into the phloem was inhibited at higher IAA levels, and the rate of filling of the transient pool(s) was reduced by IAA. IAA was detected within 10min, with the concentration increasing over 30min and reaching a steady-state by 60min. The kinetics indicated that phloem loading of IAA involving both an active, carrier-based, and a passive, diffusion-based component, with IAA traveling along a pathway containing an intermediary pool, possibly the protoplasts of mesophyll cells. Phloem loading of IAA was altered by sucrose, K(+), and a range of non-specific and IAA-specific analogs and inhibitors in a manner that showed that IAA moves into the phloem from the extra cotyledonary solution by multiple pathways, with a carrier-mediated pathway playing a principal role. PMID:27371947

  7. Global effect of indole-3-acetic acid biosynthesis on multiple virulence factors of Erwinia chrysanthemi 3937.

    PubMed

    Yang, Shihui; Zhang, Qiu; Guo, Jianhua; Charkowski, Amy O; Glick, Bernard R; Ibekwe, A Mark; Cooksey, Donald A; Yang, Ching-Hong

    2007-02-01

    Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway. PMID:17189441

  8. ANTIFUNGAL AND SPROUT REGULATORY BIOACTIVITIES OF PHENYLACETIC ACID, INDOLE-3-ACETIC ACID, AND TYROSOL ISOLATED FROM THE POTATO DRY ROT SUPPRESSIVE BACTERIUM ENTEROBACTER CLOACAE S11:T:07

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enterobacter cloacae S11:T:07 (NRRL B-21050) is a promising biological control agent which has significantly reduced both fungal dry rot disease and sprouting in lab and pilot potato storages. The metabolites phenylacetic acid (PAA), indole-3-acetic acid (IAA), and tyrosol (TSL) were isolated from ...

  9. Seed and 4-chloroindole-3-acetic acid regulation of gibberellin metabolism in pea pericarp.

    PubMed Central

    van Huizen, R; Ozga, J A; Reinecke, D M; Twitchin, B; Mander, L N

    1995-01-01

    In this study, we investigated seed and auxin regulation of gibberellin (GA) biosynthesis in pea (Pisum sativum L.) pericarp tissue in situ, specifically the conversion of [14C]GA19 to [14C]GA20. [14C]GA19 metabolism was monitored in pericarp with seeds, deseeded pericarp, and deseeded pericarp treated with 4-chloroindole-3-acetic acid (4-CI-IAA). Pericarp with seeds and deseeded pericarp treated with 4-CI-IAA continued to convert [14C]GA19 to [14C]GA20 throughout the incubation period (2-24 h). However, seed removal resulted in minimal or no accumulation of [14C]GA20 in pericarp tissue. [14C]GA29 was also identified as a product of [14C]GA19 metabolism in pea pericarp. The ratio of [14C]GA29 to [14C]GA20 was significantly higher in deseeded pericarp (with or without exogenous 4-CI-IAA) than in pericarp with seeds. Therefore, conversion of [14C]GA20 to [14C]GA29 may also be seed regulated in pea fruit. These data support the hypothesis that the conversion of GA19 to GA20 in pea pericarp is seed regulated and that the auxin 4-CI-IAA can substitute for the seeds in the stimulation of pericarp growth and the conversion of GA19 to GA20. PMID:8539289

  10. Tryptophan regulates thaxtomin A and indole-3-acetic acid production in Streptomyces scabiei and modifies its interactions with radish seedlings.

    PubMed

    Legault, Geneviève S; Lerat, Sylvain; Nicolas, Philippe; Beaulieu, Carole

    2011-09-01

    The virulence of Streptomyces scabiei, the causal agent of common scab, depends mainly on the production of the toxin thaxtomin A. S. scabiei also produces indole-3-acetic acid (IAA) but the role of this hormone in the interaction between pathogenic streptomycetes and plants has not yet been elucidated. Tryptophan is a biosynthetic precursor of both IAA and thaxtomin A. In this study, the effect of tryptophan on thaxtomin A and IAA production as well as its effect on the transcription of the corresponding biosynthetic genes in S. scabiei has been analyzed. In vitro IAA production depended on the availability of tryptophan. However, addition of this amino acid to the culture medium inhibited the biosynthesis of thaxtomin A. Expression of thaxtomin A biosynthetic genes nos and txtA were strongly repressed in the presence of tryptophan; however, modulation of the expression was not observed for the IAA biosynthetic genes iaaM and iaaH. The effects of an exogenous tryptophan supply on S. scabiei virulence were assessed on radish seedlings. Addition of tryptophan reduced symptoms on inoculated radish roots compared with seedlings grown in the absence of the bacterium, by way of inhibition of thaxtomin A production and increase of IAA biosynthesis. PMID:21521002

  11. Biofilm formation and indole-3-acetic acid production by two rhizospheric unicellular cyanobacteria.

    PubMed

    Ahmed, Mehboob; Stal, Lucas J; Hasnain, Shahida

    2014-08-01

    Microorganisms that live in the rhizosphere play a pivotal role in the functioning and maintenance of soil ecosystems. The study of rhizospheric cyanobacteria has been hampered by the difficulty to culture and maintain them in the laboratory. The present work investigated the production of the plant hormone indole-3-acetic acid (IAA) and the potential of biofilm formation on the rhizoplane of pea plants by two cyanobacterial strains, isolated from rice rhizosphere. The unicellular cyanobacteria Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 that were isolated from a rice rhizosphere, were investigated. Production of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 was measured under experimental conditions (pH and light). The bioactivity of the cyanobacterial auxin was demonstrated through the alteration of the rooting pattern of Pisum sativum seedlings. The increase in the concentration of L-tryptophan and the time that this amino acid was present in the medium resulted in a significant enhancement of the synthesis of IAA (r > 0.900 at p = 0.01). There was also a significant correlation between the concentration of IAA in the supernatant of the cyanobacteria cultures and the root length and number of the pea seedlings. Observations made by confocal laser scanning microscopy revealed the presence of cyanobacteria on the surface of the roots and also provided evidence for the penetration of the cyanobacteria in the endorhizosphere. We show that the synthesis of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 occurs under different environmental conditions and that the auxin is important for the development of the seedling roots and for establishing an intimate symbiosis between cyanobacteria and host plants. PMID:24705871

  12. Biosynthesis and Secretion of Indole-3-Acetic Acid and Its Morphological Effects on Tricholoma vaccinum-Spruce Ectomycorrhiza.

    PubMed

    Krause, Katrin; Henke, Catarina; Asiimwe, Theodore; Ulbricht, Andrea; Klemmer, Sandra; Schachtschabel, Doreen; Boland, Wilhelm; Kothe, Erika

    2015-10-01

    Fungus-derived indole-3-acetic acid (IAA), which is involved in development of ectomycorrhiza, affects both partners, i.e., the tree and the fungus. The biosynthesis pathway, excretion from fungal hyphae, the induction of branching in fungal cultures, and enhanced Hartig net formation in mycorrhiza were shown. Gene expression studies, incorporation of labeled compounds into IAA, heterologous expression of a transporter, and bioinformatics were applied to study the effect of IAA on fungal morphogenesis and on ectomycorrhiza. Tricholoma vaccinum produces IAA from tryptophan via indole-3-pyruvate, with the last step of this biosynthetic pathway being catalyzed by an aldehyde dehydrogenase. The gene ald1 was found to be highly expressed in ectomycorrhiza and induced by indole-3-acetaldehyde. The export of IAA from fungal cells is supported by the multidrug and toxic extrusion (MATE) transporter Mte1 found in T. vaccinum. The addition of IAA and its precursors induced elongated cells and hyphal ramification of mycorrhizal fungi; in contrast, in saprobic fungi such as Schizophyllum commune, IAA did not induce morphogenetic changes. Mycorrhiza responded by increasing its Hartig net formation. The IAA of fungal origin acts as a diffusible signal, influencing root colonization and increasing Hartig net formation in ectomycorrhiza. PMID:26231639

  13. Influence of 5-Methyltryptophan-Resistant Bradyrhizobium japonicum on Soybean Root Nodule Indole-3-Acetic Acid Content †

    PubMed Central

    Hunter, William J.

    1987-01-01

    Bradyrhizobium japonicum mutants resistant to 5-methyltryptophan were isolated. Some of these mutants were found to accumulate indole-3-acetic acid (IAA) and tryptophan in culture. In greenhouse studies, nodules from control plants inoculated with wild-type bradyrhizobia contained 0.04, 0.10, and 0.58 μg of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules−1, respectively. Nodules from plants inoculated with 5-methyltryptophan-resistant bradyrhizobia contained 0.94, 1.30, and 10.6 μg of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules−1, respectively. This manyfold increase in nodule IAA content indicates that the Bradyrhizobium inoculum can have a considerable influence on the endogenous IAA level of the nodule. Further, these data imply that much of the IAA that accumulated in the high-IAA-containing nodules was of bacterial rather than plant origin. These high-IAA-producing 5-methyltryptophan-resistant bacteria were poor symbiotic nitrogen fixers. Plants inoculated with these bacteria had a lower nodule mass and fixed less nitrogen per gram of nodule than did plants inoculated with wild-type bacteria. PMID:16347335

  14. Biosynthesis and Secretion of Indole-3-Acetic Acid and Its Morphological Effects on Tricholoma vaccinum-Spruce Ectomycorrhiza

    PubMed Central

    Krause, Katrin; Henke, Catarina; Asiimwe, Theodore; Ulbricht, Andrea; Klemmer, Sandra; Schachtschabel, Doreen; Boland, Wilhelm

    2015-01-01

    Fungus-derived indole-3-acetic acid (IAA), which is involved in development of ectomycorrhiza, affects both partners, i.e., the tree and the fungus. The biosynthesis pathway, excretion from fungal hyphae, the induction of branching in fungal cultures, and enhanced Hartig net formation in mycorrhiza were shown. Gene expression studies, incorporation of labeled compounds into IAA, heterologous expression of a transporter, and bioinformatics were applied to study the effect of IAA on fungal morphogenesis and on ectomycorrhiza. Tricholoma vaccinum produces IAA from tryptophan via indole-3-pyruvate, with the last step of this biosynthetic pathway being catalyzed by an aldehyde dehydrogenase. The gene ald1 was found to be highly expressed in ectomycorrhiza and induced by indole-3-acetaldehyde. The export of IAA from fungal cells is supported by the multidrug and toxic extrusion (MATE) transporter Mte1 found in T. vaccinum. The addition of IAA and its precursors induced elongated cells and hyphal ramification of mycorrhizal fungi; in contrast, in saprobic fungi such as Schizophyllum commune, IAA did not induce morphogenetic changes. Mycorrhiza responded by increasing its Hartig net formation. The IAA of fungal origin acts as a diffusible signal, influencing root colonization and increasing Hartig net formation in ectomycorrhiza. PMID:26231639

  15. Systematic profiling of indole-3-acetic acid biosynthesis in bacteria using LC-MS/MS.

    PubMed

    Lin, Guang-Huey; Chang, Chung-Yu; Lin, Huei-Ru

    2015-04-15

    Indole-3-acetic acid (IAA) is produced from tryptophan through five synthesis pathways. A comprehensive method for the quantification of IAA and biosynthesis-related intermediates in a culture medium was developed. Sample preparation was simple with protein precipitation. The analytes were separated on a superficially porous C18 silica column and detected by electrospray ionization-tandem mass spectrometry in the positive ion multiple reaction monitoring mode. The limit of detection was 0.05 μM, and the lower limits of quantification ranged from 0.05 to 2 μM. The intra-day and inter-day precision and accuracy were less than 13.96%. Ion suppression was observed, and the deuterated internal standards were used to compensate for the matrix effect. The method was applied to analyze changes in tryptophan catabolism in a culture medium of Pseudomonas putida. The proposed method is robust and suitable for the systematic profiling of IAA biosynthesis in culture supernatant. PMID:25746752

  16. A diverse assemblage of indole-3-acetic acid producing bacteria associate with unicellular green algae.

    PubMed

    Bagwell, Christopher E; Piskorska, Magdalena; Soule, Tanya; Petelos, Angela; Yeager, Chris M

    2014-08-01

    Microalgae have tremendous potential as a renewable feedstock for the production of liquid transportation fuels. In natural waters, the importance of physical associations and biochemical interactions between microalgae and bacteria is generally well appreciated, but the significance of these interactions to algal biofuels production have not been investigated. Here, we provide a preliminary report on the frequency of co-occurrence between indole-3-acetic acid (IAA)-producing bacteria and green algae in natural and engineered ecosystems. Growth experiments with unicellular algae, Chlorella and Scenedesmus, revealed IAA concentration-dependent responses in chlorophyll content and dry weight. Importantly, discrete concentrations of IAA resulted in cell culture synchronization, suggesting that biochemical priming of cellular metabolism could vastly improve the reliability of high density cultivation. Bacterial interactions may have an important influence on algal growth and development; thus, the preservation or engineered construction of the algal-bacterial assembly could serve as a control point for achieving low input, reliable production of algal biofuels. PMID:24879600

  17. Ethylene-enhanced catabolism of ( sup 14 C)indole-3-acetic acid to indole-3-carboxylic acid in citrus leaf tissues. [Citrus sinensis

    SciTech Connect

    Sagee, O.; Riov, J.; Goren, J. )

    1990-01-01

    Exogenous ({sup 14}C)indole-3-acetic acid (IAA) is conjugated in citrus (Citrus sinensis) leaf tissues to one major substance which has been identified as indole-3-acetylaspartic acid (IAAsp). Ethylene pretreatment enhanced the catabolism of ({sup 14}C)IAA to indole-3-carboxylic acid (ICA), which accumulated as glucose esters (ICGlu). Increased formation of ICGlu by ethylene was accompanied by a concomitant decrease in IAAsp formation. IAAsp and ICGlu were identified by combined gas chromatography-mass spectrometry. Formation of ICGlu was dependent on the concentration of ethylene and the duration of the ethylene pretreatment. It is suggested that the catabolism of IAA to ICA may be one of the mechanisms by which ethylene endogenous IAA levels.

  18. Biosynthesis of Indole-3-Acetic Acid by New Klebsiella oxytoca Free and Immobilized Cells on Inorganic Matrices

    PubMed Central

    Celloto, Valéria R.; Oliveira, Arildo J. B.; Gonçalves, José E.; Watanabe, Cecília S. F.; Matioli, Graciette; Gonçalves, Regina A. C.

    2012-01-01

    While many natural and synthetic compounds exhibit auxin-like activity in bioassays, indole-3-acetic acid (IAA) is recognized as the key auxin in most plants. IAA has been implicated in almost all aspects of plant growth and development and a large array of bacteria have been reported to enhance plant growth. Cells of Klebsiella oxytoca isolated from the rhizosphere of Aspidosperma polyneuron and immobilized by adsorption on different inorganic matrices were used for IAA production. The matrices were prepared by the sol-gel method and the silica-titanium was the most suitable matrix for effective immobilization. In operational stability assays, IAA production was maintained after four cycles of production, obtaining 42.80 ± 2.03 μg mL−1 of IAA in the third cycle, which corresponds to a 54% increase in production in relation to the first cycle, whereas free cells began losing activity after the first cycle. After 90 days of storage at 4°C the immobilized cells showed the slight reduction of IAA production without significant loss of activity. PMID:22623901

  19. Antibody-targeted horseradish peroxidase associated with indole-3-acetic acid induces apoptosis in vitro in hematological malignancies.

    PubMed

    Dalmazzo, Leandro F F; Santana-Lemos, Bárbara A; Jácomo, Rafael H; Garcia, Aglair B; Rego, Eduardo M; da Fonseca, Luiz M; Falcão, Roberto P

    2011-05-01

    Indole-3-acetic acid (IAA), when oxidized by horseradish peroxidase (HRP), is transformed into cytotoxic molecules capable of inducing cell injury. The aim of this study was to test if, by targeting hematopoietic tumors with HRP-conjugated antibodies in association with IAA treatment, there is induction of apoptosis. We used two lineages of hematologic tumors: NB4, derived from acute promyelocytic leukemia (APL) and Granta-519 from mantle cell lymphoma (MCL). We also tested cells from 12 patients with acute myeloid leukemia (AML) and from 10 patients with chronic lymphocytic leukemia (CLL). HRP targeting was performed with anti-CD33 or anti-CD19 antibodies (depending on the origin of the cell), followed by incubation with goat anti-mouse antibody conjugated with HRP. Eight experimental groups were analyzed: control, HRP targeted, HRP targeted and incubated with 1, 5 and 10mM IAA, and cells not HRP targeted but incubated with 1, 5 and 10mM IAA. Apoptosis was analyzed by flow cytometry using annexin V-FITC and propidium iodide labeling. Results showed that apoptosis was dependent on the dose of IAA utilized, the duration of exposure to the prodrug and the origin of the neoplasia. Targeting HRP with antibodies was efficient in activating IAA and inducing apoptosis. PMID:21168913

  20. Involvement of indole-3-acetic acid produced by Azospirillum brasilense in accumulating intracellular ammonium in Chlorella vulgaris.

    PubMed

    Meza, Beatriz; de-Bashan, Luz E; Bashan, Yoav

    2015-01-01

    Accumulation of intracellular ammonium and activities of the enzymes glutamine synthetase (GS) and glutamate dehydrogenase (GDH) were measured when the microalgae Chlorella vulgaris was immobilized in alginate with either of two wild type strains of Azospirillum brasilense or their corresponding indole-3-acetic acid (IAA)-attenuated mutants. After 48 h of immobilization, both wild types induced higher levels of intracellular ammonium in the microalgae than their respective mutants; the more IAA produced, the higher the intracellular ammonium accumulated. Accumulation of intracellular ammonium in the cells of C. vulgaris followed application of four levels of exogenous IAA reported for A. brasilense and its IAA-attenuated mutants, which had a similar pattern for the first 24 h. This effect was transient and disappeared after 48 h of incubation. Immobilization of C. vulgaris with any bacteria strain induced higher GS activity. The bacterial strains also had GS activity, comparable to the activity detected in C. vulgaris, but weaker than when immobilized with the bacteria. When net activity was calculated, the wild type always induced higher GS activity than IAA-attenuated mutants. GDH activity in most microalgae/bacteria interactions resembled GS activity. When complementing IAA-attenuated mutants with exogenous IAA, GS activity in co-immobilized cultures matched those of the wild type A. brasilense immobilized with the microalga. Similarity occurred when the net GS activity was measured, and was higher with greater quantities of exogenous IAA. It is proposed that IAA produced by A. brasilense is involved in ammonium uptake and later assimilation by C. vulgaris. PMID:25554489

  1. Circadian changes in endogenous concentrations of indole-3-acetic acid, melatonin, serotonin, abscisic acid and jasmonic acid in Characeae (Chara australis Brown)

    PubMed Central

    Beilby, Mary J; Turi, Christina E; Baker, Teesha C; Tymm, Fiona JM; Murch, Susan J

    2015-01-01

    Giant-celled Characeae (Chara australis Brown), grown for 4 months on 12/12 hr day/night cycle and summer/autumn temperatures, exhibited distinct concentration maxima in auxin (indole-3-acetic acid; IAA), melatonin and serotonin about 4 hr after subjective daybreak. These concentration peaks persisted after 3 day pretreatment in continuous darkness: confirming a circadian rhythm, rather than a response to “light on.” The plants pretreated for 3 d in continuous light exhibited several large IAA concentration maxima throughout the 24 hr. The melatonin and serotonin concentrations decreased and were less synchronized with IAA. Chara plants grown on 9/15 hr day/night cycle for 4 months and winter/spring temperatures contained much smaller concentrations of IAA, melatonin and serotonin. The IAA concentration maxima were observed in subjective dark phase. Serotonin concentration peaks were weakly correlated with those of IAA. Melatonin concentration was low and mostly independent of circadian cycle. The “dark” IAA concentration peaks persisted in plants treated for 3 d in the dark. The plants pretreated for 3 d in the light again developed more IAA concentration peaks. In this case the concentration maxima in melatonin and serotonin became more synchronous with those in IAA. The abscisic acid (ABA) and jasmonic acid (JA) concentrations were also measured in plants on winter regime. The ABA concentration did not exhibit circadian pattern, while JA concentration peaks were out of phase with those of IAA. The data are discussed in terms of crosstalk between metabolic pathways. PMID:26382914

  2. Variation in Indole-3-Acetic Acid Production by Wild Saccharomyces cerevisiae and S. paradoxus Strains from Diverse Ecological Sources and Its Effect on Growth

    PubMed Central

    Liu, Yen-Yu; Chen, Hung-Wei; Chou, Jui-Yu

    2016-01-01

    Phytohormone indole-3-acetic acid (IAA) is the most common naturally occurring and most thoroughly studied plant growth regulator. Microbial synthesis of IAA has long been known. Microbial IAA biosynthesis has been proposed as possibly occurring through multiple pathways, as has been proven in plants. However, the biosynthetic pathways of IAA and the ecological roles of IAA in yeast have not been widely studied. In this study, we investigated the variation in IAA production and its effect on the growth of Saccharomyces cerevisiae and its closest relative Saccharomyces paradoxus yeasts from diverse ecological sources. We found that almost all Saccharomyces yeasts produced IAA when cultured in medium supplemented with the primary precursor of IAA, L-tryptophan (L-Trp). However, when cultured in medium without L-Trp, IAA production was only detected in three strains. Furthermore, exogenous added IAA exerted stimulatory and inhibitory effects on yeast growth. Interestingly, a negative correlation was observed between the amount of IAA production in the yeast cultures and the IAA inhibition ratio of their growth. PMID:27483373

  3. Tryptophan, thiamine and indole-3-acetic acid exchange between Chlorella sorokiniana and the plant growth-promoting bacterium Azospirillum brasilense.

    PubMed

    Palacios, Oskar A; Gomez-Anduro, Gracia; Bashan, Yoav; de-Bashan, Luz E

    2016-06-01

    During synthetic mutualistic interactions between the microalga Chlorella sorokiniana and the plant growth-promoting bacterium (PGPB) Azospirillum brasilense, mutual exchange of resources involved in producing and releasing the phytohormone indole-3-acetic acid (IAA) by the bacterium, using tryptophan and thiamine released by the microalga, were measured. Although increased activities of tryptophan synthase in C. sorokiniana and indole pyruvate decarboxylase (IPDC) in A. brasilense were observed, we could not detect tryptophan or IAA in the culture medium when both organisms were co-immobilized. This indicates that no extra tryptophan or IAA is produced, apart from the quantities required to sustain the interaction. Over-expression of the ipdC gene occurs at different incubation times: after 48 h, when A. brasilense was immobilized alone and grown in exudates of C. sorokiniana and at 96 h, when A. brasilense was co-immobilized with the microalga. When A. brasilense was cultured in exudates of C. sorokiniana, increased expression of the ipdC gene, corresponding increase in activity of IPDC encoded by the ipdC gene, and increase in IAA production were measured during the first 48 h of incubation. IAA production and release by A. brasilense was found only when tryptophan and thiamine were present in a synthetic growth medium (SGM). The absence of thiamine in SGM yielded no detectable IAA. In summary, this study demonstrates that C. sorokiniana can exude sufficient tryptophan and thiamine to allow IAA production by a PGPB during their interaction. Thiamine is essential for IAA production by A. brasilense and these three metabolites are part of a communication between the two microorganisms. PMID:27090758

  4. Cloning and characterization of a locus encoding an indolepyruvate decarboxylase involved in indole-3-acetic acid synthesis in Erwinia herbicola.

    PubMed Central

    Brandl, M T; Lindow, S E

    1996-01-01

    Erwinia herbicola 299R synthesizes indole-3-acetic acid (IAA) primarily by the indole-3-pyruvic acid pathway. A gene involved in the biosynthesis of IAA was cloned from strain 299R. This gene (ipdC) conferred the synthesis of indole-3-acetaldehyde and tryptophol upon Escherichia coli DH5 alpha in cultures supplemented with L-tryptophan. The deduced amino acid sequence of the gene product has high similarity to that of the indolepyruvate decarboxylase of Enterobacter cloacae. Regions within pyruvate decarboxylases of various fungal and plant species also exhibited considerable homology to portions of this gene. This gene therefore presumably encodes an indolepyruvate decarboxylase (IpdC) which catalyzes the conversion of indole-3-pyruvic acid to indole-3-acetaldehyde. Insertions of Tn3-spice within ipdC abolished the ability of strain 299R to synthesize indole-3-acetaldehyde and tryptophol and reduced its IAA production in tryptophan-supplemented minimal medium by approximately 10-fold, thus providing genetic evidence for the role of the indolepyruvate pathway in IAA synthesis in this strain. An ipdC probe hybridized strongly with the genomic DNA of all E. herbicola strains tested in Southern hybridization studies, suggesting that the indolepyruvate pathway is common in this species. Maximum parsimony analysis revealed that the ipdC gene is highly conserved within this group and that strains of diverse geographic origin were very similar with respect to ipdC. PMID:8900003

  5. A mutation in the indole-3-acetic acid biosynthesis pathway of Pseudomonas syringae pv. syringae affects growth in Phaseolus vulgaris and syringomycin production.

    PubMed Central

    Mazzola, M; White, F F

    1994-01-01

    Homologs of the genes for indole-3-acetic acid (IAA) biosynthesis from Pseudomonas syringae pv. savastanoi were retrieved from a genomic library of P. syringae pv. syringae, and their nucleotide sequences were determined. Sequence relatedness between the P. syringae pv. syringae and P. syringae pv. savastanoi iaa operons is greater than 90% within the iaaM and iaaH loci but declines dramatically at a position approximately 200 bp 5' of the iaaM translation initiation codon. A third open reading frame was detected downstream of iaaH. Production of IAA was undetectable in mutant strain Y30-53.29, which was generated by transposition of Tn5 into the iaaM gene of P. syringae pv. syringae Y30. The IAA-deficient (IAA-) mutant retained the ability to colonize the bean phylloplane and induced disease symptoms on bean which were similar to those produced by the parental strain. However, the population dynamics of the IAA- strain during the parasitic phase in leaves differed from those of both the parental strain and the mutant genetically restored for IAA biosynthesis. The mutant was capable of inducing disease symptoms when established in bean tissues at a lower initial cell density than either IAA-producing strain. Syringomycin biosynthesis by the IAA- strain was diminished in comparison with the parental strain or the mutant genetically restored for IAA production. The results indicate that bacterially derived IAA, or its biosynthesis, is involved in the regulation of in planta growth and in the expression of other factors that affect the host-pathogen interaction. Images PMID:8113177

  6. Indole-3-Acetic Acid-Producing Yeasts in the Phyllosphere of the Carnivorous Plant Drosera indica L

    PubMed Central

    Shin, Li-Ying; Wei, Jyuan-Yu; Fu, Shih-Feng; Chou, Jui-Yu

    2014-01-01

    Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture. PMID:25464336

  7. Indole-3-acetic acid-induced oxidative burst and an increase in cytosolic calcium ion concentration in rice suspension culture.

    PubMed

    Nguyen, Hieu T H; Umemura, Kenji; Kawano, Tomonori

    2016-08-01

    Indole-3-acetic acid (IAA) is the major natural auxin involved in the regulation of a variety of growth and developmental processes such as division, elongation, and polarity determination in growing plant cells. It has been shown that dividing and/or elongating plant cells accompanies the generation of reactive oxygen species (ROS) and a number of reports have suggested that hormonal actions can be mediated by ROS through ROS-mediated opening of ion channels. Here, we surveyed the link between the action of IAA, oxidative burst, and calcium channel activation in a transgenic cells of rice expressing aequorin in the cytosol. Application of IAA to the cells induced a rapid and transient generation of superoxide which was followed by a transient increase in cytosolic Ca(2+) concentration ([Ca(2+)]c). The IAA-induced [Ca(2+)]c elevation was inhibited by Ca(2+) channel blockers and a Ca(2+) chelator. Furthermore, ROS scavengers effectively blocked the action of IAA on [Ca(2+)]c elevation. PMID:27149194

  8. Indole-3-acetic acid-producing yeasts in the phyllosphere of the carnivorous plant Drosera indica L.

    PubMed

    Sun, Pei-Feng; Fang, Wei-Ta; Shin, Li-Ying; Wei, Jyuan-Yu; Fu, Shih-Feng; Chou, Jui-Yu

    2014-01-01

    Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture. PMID:25464336

  9. Indole-3-Acetic Acid Is Produced by Emiliania huxleyi Coccolith-Bearing Cells and Triggers a Physiological Response in Bald Cells

    PubMed Central

    Labeeuw, Leen; Khey, Joleen; Bramucci, Anna R.; Atwal, Harjot; de la Mata, A. Paulina; Harynuk, James; Case, Rebecca J.

    2016-01-01

    Indole-3-acetic acid (IAA) is an auxin produced by terrestrial plants which influences development through a variety of cellular mechanisms, such as altering cell orientation, organ development, fertility, and cell elongation. IAA is also produced by bacterial pathogens and symbionts of plants and algae, allowing them to manipulate growth and development of their host. They do so by either producing excess exogenous IAA or hijacking the IAA biosynthesis pathway of their host. The endogenous production of IAA by algae remains contentious. Using Emiliania huxleyi, a globally abundant marine haptophyte, we investigated the presence and potential role of IAA in algae. Homologs of genes involved in several tryptophan-dependent IAA biosynthesis pathways were identified in E. huxleyi. This suggests that this haptophyte can synthesize IAA using various precursors derived from tryptophan. Addition of L-tryptophan to E. huxleyi stimulated IAA production, which could be detected using Salkowski's reagent and GC × GC-TOFMS in the C cell type (coccolith bearing), but not in the N cell type (bald). Various concentrations of IAA were exogenously added to these two cell types to identify a physiological response in E. huxleyi. The N cell type, which did not produce IAA, was more sensitive to it, showing an increased variation in cell size, membrane permeability, and a corresponding increase in the photosynthetic potential quantum yield of Photosystem II (PSII). A roseobacter (bacteria commonly associated with E. huxleyi) Ruegeria sp. R11, previously shown to produce IAA, was co-cultured with E. huxleyi C and N cells. IAA could not be detected from these co-cultures, and even when stimulated by addition of L-tryptophan, they produced less IAA than axenic C type culture similarly induced. This suggests that IAA plays a novel role signaling between different E. huxleyi cell types, rather than between a bacteria and its algal host. PMID:27375567

  10. A Microscale Technique for Gas Chromatography-Mass Spectrometry Measurements of Picogram Amounts of Indole-3-Acetic Acid in Plant Tissues.

    PubMed Central

    Edlund, A.; Eklof, S.; Sundberg, B.; Moritz, T.; Sandberg, G.

    1995-01-01

    A microscale technique has been developed for routine quantifications of picogram amounts of indole-3-acetic acid (IAA) in plant tissues by combined gas chromatography-mass spectrometry. Low- and high-resolution selected-ion-monitoring and selected-reaction-monitoring mass spectrometry techniques were compared for selectivity and precision. The best selectivity was obtained with selected-reaction-monitoring analysis, and 1-mg samples containing 500 fg of IAA could be analyzed accurately with this method. This technique was used to investigate the IAA distribution pattern along the longitudinal axis of tobacco (Nicotiana tabacum [L.]) leaves. In young, developing leaves an increase of endogenous IAA from the leaf tip to the base of the leaf was observed, whereas the level of IAA was uniform along this axis in mature leaves. PMID:12228526

  11. Indole-3-Acetic Acid Biosynthesis in Colletotrichum gloeosporioides f. sp. aeschynomene

    PubMed Central

    Robinson, M.; Riov, J.; Sharon, A.

    1998-01-01

    We characterized the biosynthesis of indole-3-acetic acid by the mycoherbicide Colletotrichum gloeosporioides f. sp. aeschynomene. Auxin production was tryptophan dependent. Compounds from the indole-3-acetamide and indole-3-pyruvic acid pathways were detected in culture filtrates. Feeding experiments and in vitro assay confirmed the presence of both pathways. Indole-3-acetamide was the major pathway utilized by the fungus to produce indole-3-acetic acid in culture. PMID:9835603

  12. The role of calcium in growth induced by indole-3-acetic acid and gravity in the leaf-sheath pulvinus of oat (Avena sativa)

    NASA Technical Reports Server (NTRS)

    Brock, T. G.; Burg, J.; Ghosheh, N. S.; Kaufman, P. B.

    1992-01-01

    Leaf-sheath pulvini of excised segments from oat (Avena sativa L.) were induced to grow by treatment with 10 micromoles indole-3-acetic acid (IAA), gravistimulation, or both, and the effects of calcium, EGTA, and calcium channel blockers on growth were evaluated. Unilaterally applied calcium (10 mM CaCl2) significantly inhibited IAA-induced growth in upright pulvini but had no effect on growth induced by either gravity or gravity plus IAA. Calcium alone had no effect on upright pulvini. The calcium chelator EGTA alone (10 mM) stimulated growth in upright pulvini. However, EGTA had no effect on either IAA- or gravity-induced growth but slightly diminished growth in IAA-treated gravistimulated pulvini. The calcium channel blockers lanthanum chloride (25 mM), verapamil (2.5 mM), and nifedipine (2.5 mM) greatly inhibited growth as induced by IAA (> or = 50% inhibition) or IAA plus gravity (20% inhibition) but had no effect on gravistimulated pulvini. Combinations of channel blockers were similar in effect on IAA action as individual blockers. Since neither calcium ions nor EGTA significantly affected the graviresponse of pulvini, we conclude that apoplastic calcium is unimportant in leaf-sheath pulvinus gravitropism. The observation that calcium ions and calcium channel blockers inhibit IAA-induced growth, but have no effect on gravistimulated pulvini, further supports previous observations that gravistimulation alters the responsiveness of pulvini to IAA.

  13. Global Effect of Indole-3-Acetic Acid Biosynthesis on Multiple Virulence Factors of Erwinia chrysanthemi 3937▿

    PubMed Central

    Yang, Shihui; Zhang, Qiu; Guo, Jianhua; Charkowski, Amy O.; Glick, Bernard R.; Ibekwe, A. Mark; Cooksey, Donald A.; Yang, Ching-Hong

    2007-01-01

    Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway. PMID:17189441

  14. Biosynthesis of the Halogenated Auxin, 4-Chloroindole-3-Acetic Acid1[W][OA

    PubMed Central

    Tivendale, Nathan D.; Davidson, Sandra E.; Davies, Noel W.; Smith, Jason A.; Dalmais, Marion; Bendahmane, Abdelhafid I.; Quittenden, Laura J.; Sutton, Lily; Bala, Raj K.; Le Signor, Christine; Thompson, Richard; Horne, James; Reid, James B.; Ross, John J.

    2012-01-01

    Seeds of several agriculturally important legumes are rich sources of the only halogenated plant hormone, 4-chloroindole-3-acetic acid. However, the biosynthesis of this auxin is poorly understood. Here, we show that in pea (Pisum sativum) seeds, 4-chloroindole-3-acetic acid is synthesized via the novel intermediate 4-chloroindole-3-pyruvic acid, which is produced from 4-chlorotryptophan by two aminotransferases, TRYPTOPHAN AMINOTRANSFERASE RELATED1 and TRYPTOPHAN AMINOTRANSFERASE RELATED2. We characterize a tar2 mutant, obtained by Targeting Induced Local Lesions in Genomes, the seeds of which contain dramatically reduced 4-chloroindole-3-acetic acid levels as they mature. We also show that the widespread auxin, indole-3-acetic acid, is synthesized by a parallel pathway in pea. PMID:22573801

  15. Development of indole-3-acetic acid-producing Escherichia coli by functional expression of IpdC, AspC, and Iad1.

    PubMed

    Romasi, Elisa Friska; Lee, Jinho

    2013-12-01

    Biosynthesis of indole-3-acetic acid (IAA) via the indole-3-pyruvic acid pathway involves three kinds of enzymes; aminotransferase encoded by aspC, indole-3-pyruvic acid decarboxylase encoded by ipdC, and indole-3-acetic acid dehydrogenase encoded by iad1. The ipdC from Enterobacter cloacae ATCC 13047, aspC from Escherichia coli, and iad1 from Ustilago maydis were cloned and expressed under the control of the tac and sod promoters in E. coli. According to SDS-PAGE and enzyme activity, IpdC and Iad1 showed good expression under the control of P(tac), whereas AspC was efficiently expressed by P(sod) originating from Corynebacterium glutamicum. The activities of IpdC, AspC, and Iad1 from the crude extracts of recombinant E. coli Top 10 were 215.6, 5.7, and 272.1 nmol/min/mg-protein, respectively. The recombinant E. coli DH5α expressing IpdC, AspC, and Iad1 produced about 1.1 g/l of IAA and 0.13 g/l of tryptophol (TOL) after 48 h of cultivation in LB medium with 2 g/l tryptophan. To improve IAA production, a tnaA gene mediating indole formation from tryptophan was deleted. As a result, E. coli IAA68 with expression of the three genes produced 1.8 g/l of IAA, which is a 1.6- fold increase compared with wild-type DH5α harboring the same plasmids. Moreover, the complete conversion of tryptophan to IAA was achieved by E. coli IAA68. Finally, E. coli IAA68 produced 3.0 g/l of IAA after 24 h cultivation in LB medium supplemented with 4 g/l of tryptophan. PMID:24043123

  16. Effect of exogenous indole-3-acetic acid and naphthalene acetic acid on regeneration of damask rose cuttings in three growing media.

    PubMed

    Khan, Rahmat Ullah; Khan, Muhammad Sohail; Rashid, Abdur; Farooq, Arshad

    2007-10-15

    An experiment was conducted to evaluate the performance of various levels of indole-3-acetic acid (IAA) and naphthalene acetic acid (NAA) treatments i.e., 0, 25, 50, 75, 100 mg L(-1) on the regeneration of damask rose (Rosa damascena Mill.) cuttings in different growing media at the research farm of Arid Zone Research Institute D.I. Khan during 2004. The data revealed significant effect of different levels of growth regulators and growing media on the rose establishment parameters viz., plant height, plant spread, number of primary shoots, secondary shoots and survival percentage. Maximum plant height (134.2 cm), plant spread (46.3 cm), primary shoots (6.3), secondary shoots (25) and survival percentage (94.72%) were recorded when the rose cuttings were applied with NAA at the rate of 50 mg L(-1). Among the plant growth regulators, Naphthalene Acetic Acid (NAA) was found to be superior to indole-3-acetic acid (IAA) for its stronger effect regarding all parameters. The optimum level of Naphthalene Acetic Acid (NAA) was found in the range of 50 and 75 mg L(-1), while no such conclusion could be drawn for indole-3-acetic acid (IAA) as all growth parameters were linearly increased up to the highest concentrations of IAA i.e., 100 mg L(-1). Regarding growing media, the leaf mould appeared the best in terms of its positive effect on establishment of rose cuttings by giving the maximum plant height (125.1 cm), plant spread (37 cm), primary shoots (5.2), secondary shoots (19.48) and survival percentage (85.67%), followed by soil + leaf mould, while soil media was least effective. PMID:19093472

  17. Amide-conjugated indole-3-acetic acid and adventitious root formation in mung bean cuttings

    SciTech Connect

    Norcini, J.G.

    1986-01-01

    The purpose of this research was to investigate further the relationship between amide-conjugated auxin and adventitious root formation. Indoleacetylaspartic acid (IAA-aspartate) was positively identified as the predominant conjugate isolated from mung bean cuttings after the cuttings has been treated with 10/sup -3/ M IAA. In cuttings treated with (1-/sup 14/C)IAA immediately after excision (0 hr), the percent of extractable /sup 14/C in IAA-aspartate in the hypocotyl sharply increased until 36 hr, then steadily declined. (/sup 14/C)IAA was completely metabolized between 12 and 24 hr. The rooting activities of IAA-L-aspartate, IAA-L-alanine, and IAA-glycine were determined at various stages of root formation; some cuttings were pretreated with 10/sup -3/ M IAA at 0 hr. Pretreated cuttings that were treated with IAA-glycine at 12, 24, 36 hr exhibited the greatest consistency between replications, the greatest number of long roots, and the longest roots. The conjugates did not stimulate rooting as effectively as IAA, yet like IAA, generally enhanced rooting the greatest when applied before the first cell division (24 hr).

  18. Distinct Characteristics of Indole-3-Acetic Acid and Phenylacetic Acid, Two Common Auxins in Plants.

    PubMed

    Sugawara, Satoko; Mashiguchi, Kiyoshi; Tanaka, Keita; Hishiyama, Shojiro; Sakai, Tatsuya; Hanada, Kousuke; Kinoshita-Tsujimura, Kaori; Yu, Hong; Dai, Xinhua; Takebayashi, Yumiko; Takeda-Kamiya, Noriko; Kakimoto, Tatsuo; Kawaide, Hiroshi; Natsume, Masahiro; Estelle, Mark; Zhao, Yunde; Hayashi, Ken-Ichiro; Kamiya, Yuji; Kasahara, Hiroyuki

    2015-08-01

    The phytohormone auxin plays a central role in many aspects of plant growth and development. IAA is the most studied natural auxin that possesses the property of polar transport in plants. Phenylacetic acid (PAA) has also been recognized as a natural auxin for >40 years, but its role in plant growth and development remains unclear. In this study, we show that IAA and PAA have overlapping regulatory roles but distinct transport characteristics as auxins in plants. PAA is widely distributed in vascular and non-vascular plants. Although the biological activities of PAA are lower than those of IAA, the endogenous levels of PAA are much higher than those of IAA in various plant tissues in Arabidopsis. PAA and IAA can regulate the same set of auxin-responsive genes through the TIR1/AFB pathway in Arabidopsis. IAA actively forms concentration gradients in maize coleoptiles in response to gravitropic stimulation, whereas PAA does not, indicating that PAA is not actively transported in a polar manner. The induction of the YUCCA (YUC) genes increases PAA metabolite levels in Arabidopsis, indicating that YUC flavin-containing monooxygenases may play a role in PAA biosynthesis. Our results provide new insights into the regulation of plant growth and development by different types of auxins. PMID:26076971

  19. Distinct Characteristics of Indole-3-Acetic Acid and Phenylacetic Acid, Two Common Auxins in Plants

    PubMed Central

    Sugawara, Satoko; Mashiguchi, Kiyoshi; Tanaka, Keita; Hishiyama, Shojiro; Sakai, Tatsuya; Hanada, Kousuke; Kinoshita-Tsujimura, Kaori; Yu, Hong; Dai, Xinhua; Takebayashi, Yumiko; Takeda-Kamiya, Noriko; Kakimoto, Tatsuo; Kawaide, Hiroshi; Natsume, Masahiro; Estelle, Mark; Zhao, Yunde; Hayashi, Ken-ichiro; Kamiya, Yuji; Kasahara, Hiroyuki

    2015-01-01

    The phytohormone auxin plays a central role in many aspects of plant growth and development. IAA is the most studied natural auxin that possesses the property of polar transport in plants. Phenylacetic acid (PAA) has also been recognized as a natural auxin for >40 years, but its role in plant growth and development remains unclear. In this study, we show that IAA and PAA have overlapping regulatory roles but distinct transport characteristics as auxins in plants. PAA is widely distributed in vascular and non-vascular plants. Although the biological activities of PAA are lower than those of IAA, the endogenous levels of PAA are much higher than those of IAA in various plant tissues in Arabidopsis. PAA and IAA can regulate the same set of auxin-responsive genes through the TIR1/AFB pathway in Arabidopsis. IAA actively forms concentration gradients in maize coleoptiles in response to gravitropic stimulation, whereas PAA does not, indicating that PAA is not actively transported in a polar manner. The induction of the YUCCA (YUC) genes increases PAA metabolite levels in Arabidopsis, indicating that YUC flavin-containing monooxygenases may play a role in PAA biosynthesis. Our results provide new insights into the regulation of plant growth and development by different types of auxins. PMID:26076971

  20. Relationship between Indole-3-Acetic Acid Levels in Apple (Malus pumila Mill) Rootstocks Cultured in Vitro and Adventitious Root Formation in the Presence of Indole-3-Butyric Acid.

    PubMed

    Alvarez, R; Nissen, S J; Sutter, E G

    1989-02-01

    In vitro rooting response and indole-3-acetic acid (IAA) levels were examined in two genetically related dwarfing apple (Malus pumila Mill) rootstocks. M.26 and M.9 were cultured in vitro using Linsmaier-Skoog medium supplemented with benzyladenine (BA), indole-3-butyric acid (IBA), and 1,3,5-trihydroxybenzoic acid (PG). Rooting response was tested in Lepoivre medium supplemented with IBA and PG. IBA concentrations of 12.0 and 4.0 micromolar induced the maximum rooting percentages for M.9 and M.26, respectively. At these concentrations rooting response was 100% for M.26 and 80% for M.9. Free and conjugated IAA levels were determined in M.26 and M.9 shoots prior to root inducing treatment by high performance liquid chromatography with fluorescence detection and validated by gas chromatography-mass spectrometry using (13)[C(6)]IAA as internal standard. Basal sections of M.26 shoots contained 2.8 times more free IAA than similar tissue in M.9 (477.1 +/- 6.5 versus 166.6 +/- 6.7 nanograms per gram fresh weight), while free IAA levels in apical sections of M.26 and M.9 shoots were comparable (298.0 +/- 4.4 versus 263.7 +/- 9.3 nanograms per gram fresh weight). Conjugated IAA levels were significantly higher in M.9 than in M.26 indicating that a greater proportion of total IAA was present as a conjugate in M.9. These data suggest that differences between M.26 and M.9 rooting responses may be related to differences in free IAA levels in the shoot base. PMID:16666562

  1. Indole-3-Acetic Acid Produced by Burkholderia heleia Acts as a Phenylacetic Acid Antagonist to Disrupt Tropolone Biosynthesis in Burkholderia plantarii

    PubMed Central

    Wang, Mengcen; Tachibana, Seiji; Murai, Yuta; Li, Li; Lau, Sharon Yu Ling; Cao, Mengchao; Zhu, Guonian; Hashimoto, Makoto; Hashidoko, Yasuyuki

    2016-01-01

    Burkholderia heleia PAK1-2 is a potent biocontrol agent isolated from rice rhizosphere, as it prevents bacterial rice seedling blight disease caused by Burkholderia plantarii. Here, we isolated a non-antibacterial metabolite from the culture fluid of B. heleia PAK1-2 that was able to suppress B. plantarii virulence and subsequently identified as indole-3-acetic acid (IAA). IAA suppressed the production of tropolone in B. plantarii in a dose-dependent manner without any antibacterial and quorum quenching activity, suggesting that IAA inhibited steps of tropolone biosynthesis. Consistent with this, supplementing cultures of B. plantarii with either L-[ring-2H5]phenylalanine or [ring-2H2~5]phenylacetic acid revealed that phenylacetic acid (PAA), which is the dominant metabolite during the early growth stage, is a direct precursor of tropolone. Exposure of B. plantarii to IAA suppressed production of both PAA and tropolone. These data particularly showed that IAA produced by B. heleia PAK1-2 disrupts tropolone production during bioconversion of PAA to tropolone via the ring-rearrangement on the phenyl group of the precursor to attenuate the virulence of B. plantarii. B. heleia PAK1-2 is thus likely a microbial community coordinating bacterium in rhizosphere ecosystems, which never eliminates phytopathogens but only represses production of phytotoxins or bacteriocidal substances. PMID:26935539

  2. Indole-3-Acetic Acid Produced by Burkholderia heleia Acts as a Phenylacetic Acid Antagonist to Disrupt Tropolone Biosynthesis in Burkholderia plantarii.

    PubMed

    Wang, Mengcen; Tachibana, Seiji; Murai, Yuta; Li, Li; Lau, Sharon Yu Ling; Cao, Mengchao; Zhu, Guonian; Hashimoto, Makoto; Hashidoko, Yasuyuki

    2016-01-01

    Burkholderia heleia PAK1-2 is a potent biocontrol agent isolated from rice rhizosphere, as it prevents bacterial rice seedling blight disease caused by Burkholderia plantarii. Here, we isolated a non-antibacterial metabolite from the culture fluid of B. heleia PAK1-2 that was able to suppress B. plantarii virulence and subsequently identified as indole-3-acetic acid (IAA). IAA suppressed the production of tropolone in B. plantarii in a dose-dependent manner without any antibacterial and quorum quenching activity, suggesting that IAA inhibited steps of tropolone biosynthesis. Consistent with this, supplementing cultures of B. plantarii with either L-[ring-(2)H5]phenylalanine or [ring-(2)H2~5]phenylacetic acid revealed that phenylacetic acid (PAA), which is the dominant metabolite during the early growth stage, is a direct precursor of tropolone. Exposure of B. plantarii to IAA suppressed production of both PAA and tropolone. These data particularly showed that IAA produced by B. heleia PAK1-2 disrupts tropolone production during bioconversion of PAA to tropolone via the ring-rearrangement on the phenyl group of the precursor to attenuate the virulence of B. plantarii. B. heleia PAK1-2 is thus likely a microbial community coordinating bacterium in rhizosphere ecosystems, which never eliminates phytopathogens but only represses production of phytotoxins or bacteriocidal substances. PMID:26935539

  3. Laterally applied Ethrel causes local increases in radial growth and indole-3-acetic acid concentration in Abies balsamea shoots.

    PubMed

    Eklund, L; Anthony Little, C H

    1996-05-01

    The terminal (1-year-old) shoot of quiescent, two-year-old balsam fir (Abies balsamea (L.) Mill.) seedlings was ringed with lanolin containing 0, 1 or 10 mg g(-1) Ethrel, an ethylene-generating compound, and cultured for 6 weeks under environmental conditions favorable for growth. Bud break and the elongation of the current-year terminal shoot were monitored, and the subjacent previous-year terminal shoot that had been treated with Ethrel was harvested to measure stem radial growth by microscopy, shoot ethylene evolution by gas chromatography, and cambial region indole-3-acetic acid (IAA) concentration by combined gas chromatography-mass spectrometry. Compared with the lanolin controls, Ethrel at 1 and 10 mg g(-1) did not affect bud break or longitudinal growth, but stimulated tracheid production and bark increment up to about 2-fold at the application site, though not above or below it. In addition, the 1 and 10 mg g(-1) Ethrel treatments increased the cambial region IAA concentration about 3-fold and the evolution of ethylene at least 40-fold at the application site, compared with unwounded portions of both treated and control shoots. The 10 mg g(-1) Ethrel treatment also stimulated ethylene evolution about 10-fold, both above and below the application site. However, this stimulation was not associated with an elevation in cambial region IAA concentration. Similarly, the lanolin control treatment increased ethylene evolution at the application site about 10-fold, without affecting the cambial region IAA concentration. Our results suggest that the localized stimulation of radial growth in woody shoots ringed with Ethrel is mediated by an increase in IAA concentration, which in turn is induced by a threshold, abnormally high concentration of Ethrel-derived ethylene. PMID:14871721

  4. First chemoenzymatic synthesis of (+)-2-carboxypyrrolidine-3-acetic acid, the nucleus of kainoid amino acids.

    PubMed

    Felluga, Fulvia; Forzato, Cristina; Nitti, Patrizia; Pitacco, Giuliana; Ghelfi, Franco; Valentin, Ennio

    2012-02-01

    The distinctive nucleus of kainoid amino acids, (2S,3R)-(+)-2-carboxypyrrolidine-3-acetic acid 6, was synthesized by a chemoenzymatic process, exploiting the diastereomeric cis/trans methyl pyroglutamate derivatives 10a-c/11a-c as key intermediates. These mixtures, when subjected to a kinetic resolution mediated by α-chymotrypsin, reacted diastereo-, regio-, and enantioselectively to give the trans derivatives (+)-10a-c possessing the correct (2S,3R) configuration. Subsequently, the desired product (2S,3R)-(+)-6 could be obtained after well-established transformations. PMID:22180179

  5. A genome-wide analysis of the auxin/indole-3-acetic acid gene family in hexaploid bread wheat (Triticum aestivum L.)

    PubMed Central

    Qiao, Linyi; Zhang, Xiaojun; Han, Xiao; Zhang, Lei; Li, Xin; Zhan, Haixian; Ma, Jian; Luo, Peigao; Zhang, Wenping; Cui, Lei; Li, Xiaoyan; Chang, Zhijian

    2015-01-01

    The Auxin/indole-3-acetic acid (Aux/IAA) gene family plays key roles in the primary auxin-response process and controls a number of important traits in plants. However, the characteristics of the Aux/IAA gene family in hexaploid bread wheat (Triticum aestivum L.) have long been unknown. In this study, a comprehensive identification of the Aux/IAA gene family was performed using the latest draft genome sequence of the bread wheat “Chinese Spring.” Thirty-four Aux/IAA genes were identified, 30 of which have duplicated genes on the A, B or D sub-genome, with a total of 84 Aux/IAA sequences. These predicted Aux/IAA genes were non-randomly distributed in all the wheat chromosomes except for chromosome 2D. The information of wheat Aux/IAA proteins is also described. Based on an analysis of phylogeny, expression and adaptive evolution, we prove that the Aux/IAA family in wheat has been replicated twice in the two allopolyploidization events of bread wheat, when the tandem duplication also occurred. The duplicated genes have undergone an evolutionary process of purifying selection, resulting in the high conservation of copy genes among sub-genomes and functional redundancy among several members of the TaIAA family. However, functional divergence probably existed in most TaIAA members due to the diversity of the functional domain and expression pattern. Our research provides useful information for further research into the function of Aux/IAA genes in wheat. PMID:26483801

  6. Location of transported auxin in etiolated maize shoots using 5-azidoindole-3-acetic acid. [Zea mays L

    SciTech Connect

    Jones, A.M. )

    1990-07-01

    A study was undertaken using the photoaffinity labeling agent, tritiated 5-azidoindole-3-acetic acid (({sup 3}H),5-N{sub 3}IAA), to identify cells in the etiolated maize (Zea mays L.) shoot which transport auxin. Transport of ({sup 3}H),5-N{sub 3}IAA was shown to be polar, inhibited by 2,3,5-triiodobenzoic acid (TIBA) and essentially freely mobile. There was no detectable radiodecomposition of ({sup 3}H),5-N{sub 3}IAA within tissue kept in darkness for 4 hours. Shoot tissue which had taken up ({sup 3}H),5-N{sub 3}IAA was irradiated with ultraviolet light to covalently fix the photoaffinity labeling agent within cells that contained it at the time of photolysis. Subsequent microautoradiography showed that all cells contained radioactivity; however, the amount of radioactivity varied among different cell types. Epidermal cells contained the most radioactivity per area, approximately twofold more than other cells. Parenchyma cells in the mature stelar region contained the next largest amount and cortical cells, sieve tube cells, tracheary cells, and all cells in the leaf base contained the least amount of the radioactive label. Two observations suggest that the auxin within the epidermal cells is transported in a polar manner: (a) the amount of auxin in the epidermal cells is greatly reduced in the presence of TIBA, and (b) auxin accumulates on the apical side of a wound in the epidermis and is absent on the basal side. While these results indicate that auxin in the epidermis is polarly transported, this tissue cannot be the only pathway since the epidermis is only a small fraction of the shoot volume.

  7. Comparative Indole-3-Acetic Acid Levels in the Slender Pea and Other Pea Phenotypes 1

    PubMed Central

    Law, David M.; Davies, Peter J.

    1990-01-01

    Free indole-3-acetic acid levels were measured by gas chromatography-mass spectrometry in three ultra-tall `slender' Pisum sativum L. lines differing in gibberellin content. Measurements were made for apices and stem elongation zones of light-grown plants and values were compared with wild-type, dwarf, and nana phenotypes in which internode length is genetically regulated, purportedly via the gibberellin level. Indole-3-acetic acid levels of growing stems paralleled growth rates in all lines, and were high in all three slender genotypes. Growth was inhibited by p-chlorophenoxyisobutyric acid, demonstrating the requirement of auxin activity for stem elongation, and also by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid. It is concluded that the slender phenotype may arise from constant activation of a gibberellin receptor or transduction chain event leading directly or indirectly to elevated levels of indole-3-acetic acid, and that increased indole-3-acetic acid levels are a significant factor in the promotion of stem elongation. PMID:16667653

  8. Stable isotope labeling, in vivo, of D- and L-tryptophan pools in lemna gibba and the low incorporation of label into indole-3-acetic acid

    SciTech Connect

    Baldi, B.G. ); Maher, B.R. ); Slovin, J.P.; Cohen, J.D. Univ. of Maryland, College Park )

    1991-04-01

    The authors present evidence that the role of tryptophan and other potential intermediates in the pathways that could lead to indole derivatives needs to be reexamined. Two lines of Lemna gibba were tested for uptake of ({sup 15}N-indole)-labeled tryptophan isomers and incorporation of that label into free indole-3-acetic acid (IAA). Both lines required levels of L-({sup 15}N)tryptophan 2 to 3 orders of magnitude over endogenous levels in order to obtain measurable incorporation of label into IAA. Labeled L-tryptophan was extractable from plant tissue after feeding and showed no measurable isomerization into D-tryptophan. D-({sup 15}N)trytophan supplied to Lemna at rates of approximately 400 times excess of endogenous D-tryptophan levels (to yield an isotopic enrichment equal to that which allowed detection of the incorporation of L-tryptophan into IAA), did not result in measurable incorporation of label into free IAA. These results demonstrate that L-tryptophan is a more direct precursor to IAA than the D isomer and suggest (a) that the availability of tryptophan in vivo is not a limiting factor in the biosynthesis of IAA, thus implying that other regulatory mechanisms are in operation and (b) that L-tryptophan also may not be a primary precursor to IAA in plants.

  9. Differential involvement of indole-3-acetic acid biosynthetic pathways in pathogenicity and epiphytic fitness of Erwinia herbicola pv. gypsophilae.

    PubMed

    Manulis, S; Haviv-Chesner, A; Brandl, M T; Lindow, S E; Barash, I

    1998-07-01

    Erwinia herbicola pv. gypsophilae (Ehg), which induces galls on Gypsophila paniculata, harbors two major pathways for indole-3-acetic acid (IAA) synthesis, the indole-3-acetamide (IAM) and indole-3-pyruvate (IPyA) routes, as well as cytokinin biosynthetic genes. Mutants were generated in which the various biosynthetic routes were disrupted separately or jointly in order to assess the contribution of IAA of various origins and cytokinins to pathogenicity and epiphytic fitness. Inactivation of the IAM pathway or cytokinin biosynthesis caused the largest reduction in gall size. Inactivation of the IPyA pathway caused a minor, nonsignificant decrease in pathogenicity. No further reduction in gall size was observed by the simultaneous inactivation of both IAA pathways only or in combination with that of cytokinin production. However, inactivation of the IPyA pathway caused a 14-fold reduction in the population of Ehg on bean plants. Inactivation of the IAM pathway or cytokinin production did not affect epiphytic fitness. While the apparent transcriptional activity of iaaM-inaZ fusion increased slightly in cells of Ehg on bean and gypsophila leaves, compared with that in culture, very high levels of induction were observed in cells injected into gypsophila stems. In contrast, moderate levels of induction of ipdC-inaZ in Ehg were observed on leaves of these plants and in gypsophila stems, when compared with that in culture. These results suggest that the IAM pathway is involved primarily in gall formation and support the main contribution of the IpyA pathway to the epiphytic fitness of this bacterial species. PMID:9650296

  10. 7-Azaindole-3-acetic acid derivatives: potent and selective CRTh2 receptor antagonists.

    PubMed

    Sandham, David A; Adcock, Claire; Bala, Kamlesh; Barker, Lucy; Brown, Zarin; Dubois, Gerald; Budd, David; Cox, Brian; Fairhurst, Robin A; Furegati, Markus; Leblanc, Catherine; Manini, Jodie; Profit, Rachael; Reilly, John; Stringer, Rowan; Schmidt, Alfred; Turner, Katharine L; Watson, Simon J; Willis, Jennifer; Williams, Gareth; Wilson, Caroline

    2009-08-15

    High throughput screening identified a 7-azaindole-3-acetic acid scaffold as a novel CRTh2 receptor antagonist chemotype, which could be optimised to furnish a highly selective compound with good functional potency for inhibition of human eosinophil shape change in whole blood and oral bioavailability in the rat. PMID:19592244

  11. Isolation and characterization of esters of indole-3-acetic acid from the liquid endosperm of the horse chestnut (Aesculus species)

    NASA Technical Reports Server (NTRS)

    Domagalski, W.; Schulze, A.; Bandurski, R. S.

    1987-01-01

    Esters of indole-3-acetic acid were extracted and purified from the liquid endosperm of immature fruits of various species of the horse chestnut (Aesculus parviflora, A. baumanni, A. pavia rubra, and A. pavia humulis). The liquid endosperm contained, at least 12 chromatographically distinct esters. One of these compounds was purified and characterized as an ester of indole-3-acetic acid and myo-inositol. A second compound was found to be an ester of indole-3-acetic acid and the disaccharide rutinose (glucosyl-rhamnose). A third compound was partially characterized as an ester of indole-3-acetic acid and a desoxyaminohexose.

  12. Overproduction of Indole-3-Acetic Acid in Free-Living Rhizobia Induces Transcriptional Changes Resembling Those Occurring in Nodule Bacteroids.

    PubMed

    Defez, Roberto; Esposito, Roberta; Angelini, Claudia; Bianco, Carmen

    2016-06-01

    Free-living bacteria grown under aerobic conditions were used to investigate, by next-generation RNA sequencing analysis, the transcriptional profiles of Sinorhizobium meliloti wild-type 1021 and its derivative, RD64, overproducing the main auxin indole-3-acetic acid (IAA). Among the upregulated genes in RD64 cells, we detected the main nitrogen-fixation regulator fixJ, the two intermediate regulators fixK and nifA, and several other genes known to be FixJ targets. The gene coding for the sigma factor RpoH1 and other genes involved in stress response, regulated in a RpoH1-dependent manner in S. meliloti, were also induced in RD64 cells. Under microaerobic condition, quantitative real-time polymerase chain reaction analysis revealed that the genes fixJL and nifA were up-regulated in RD64 cells as compared with 1021 cells. This work provided evidence that the overexpression of IAA in S. meliloti free-living cells induced many of the transcriptional changes that normally occur in nitrogen-fixing root nodule. PMID:27003799

  13. Influence of tryptophan and indole-3-acetic acid on starch accumulation in the synthetic mutualistic Chlorella sorokiniana-Azospirillum brasilense system under heterotrophic conditions.

    PubMed

    Palacios, Oskar A; Choix, Francisco J; Bashan, Yoav; de-Bashan, Luz E

    2016-06-01

    This study measured the relations between tryptophan production, the phytohormone indole-3-acetic acid (IAA) and the metabolism and accumulation of starch during synthetic mutualism between the microalgae Chlorella sorokiniana and the microalgae growth-promoting bacteria Azospirillum brasilense, created by co-immobilization in alginate beads. Experiments used two wild-type A. brasilense strains (Cd and Sp6) and an IAA-attenuated mutant (SpM7918) grown under nitrogen-replete and nitrogen-starved conditions tested under dark, heterotrophic and aerobic growth conditions. Under all incubating conditions, C. sorokiniana, but not A. brasilense, produced tryptophan. A significant correlation between IAA-production by A. brasilense and starch accumulation in C. sorokiniana was found, since the IAA-attenuated mutant was not producing increased starch levels. The highest ADP-glucose pyrophosphorylase (AGPase) activity, starch content and glucose uptake were found during the interaction of A. brasilense wild type strains with the microalgae. When the microalgae were grown alone, they produced only small amounts of starch. Supplementation with synthetic IAA to C. sorokiniana grown alone enhanced the above parameters, but only transiently. Activity of α-amylase decreased under nitrogen-replete conditions, but increased under nitrogen-starved conditions. In summary, this study demonstrated that, during synthetic mutualism, the exchange of tryptophan and IAA between the partners is a mechanism that governs several changes in starch metabolism of C. sorokiniana, yielding an increase in starch content. PMID:26924113

  14. Diversity of culturable yeasts in phylloplane of sugarcane in Thailand and their capability to produce indole-3-acetic acid.

    PubMed

    Limtong, Savitree; Kaewwichian, Rungluk; Yongmanitchai, Wichien; Kawasaki, Hiroko

    2014-06-01

    Yeasts were isolated by the enrichment technique from the phylloplane of 94 samples of sugarcane leaf collected from seven provinces in Thailand. All sugarcane leaf samples contained yeasts and 158 yeast strains were obtained. On the basis of the D1/D2 domain of the large subunit rRNA gene sequence analysis, 144 strains were identified to 24 known species in 14 genera belonging to the Ascomycota viz. Candida akabanensis, Candida dendronema, Candida mesorugosa, Candida michaelii, Candida nivariensis, Candida rugosa, Candida orthopsilosis, Candida quercitrusa, Candida tropicalis, Candida xylopsoci, Cyberlindnera fabianii, Cyberlindnera rhodanensis, Debaryomyces nepalensis, Hannaella aff. coprosmaensis, Hanseniaspora guilliermondii, Kluyveromyces marxianus, Lachancea thermotolerans, Lodderomyces elongisporus, Metschnikowia koreensis, Meyerozyma caribbica, Millerozyma koratensis, Pichia kudriavzevii, Torulaspora delbrueckii and Wickerhamomyces edaphicus, and 12 species in six genera of the Basidiomycota viz . Cryptococcus flavescens, Cryptococcus laurentii, Cryptococcus rajasthanensis, Kwoniella heveanensis, Rhodosporidium fluviale, Rhodosporidium paludigenum, Rhodotorula mucilaginosa, Rhodotorula sesimbrana, Rhodotorula taiwanensis, Sporidiobolus ruineniae, Sporobolomyces carnicolor and Sporobolomyces nylandii. Seven strains were identical or similar to four undescribed species. Another seven strains represented four novels species in the genus Metschnikowia, Nakazawaea, Wickerhamomyces and Yamadazyma. The results revealed 69 % of the isolated strains were ascomycete yeasts and 31 % were basidiomycete yeast. The most prevalent species was M. caribbica with a 23 % frequency of occurrence followed by Rh. taiwanensis (11 %) and C. tropicalis (10 %). All strains were assessed for indole-3-acetic acid (IAA) producing capability showing that 69 strains had the capability of producing IAA when cultivated in yeast extract peptone dextrose broth supplemented with 1

  15. Effect of Exogenous Indole-3-Acetic Acid and Indole-3-Butyric Acid on Internal Levels of the Respective Auxins and Their Conjugation with Aspartic Acid during Adventitious Root Formation in Pea Cuttings.

    PubMed

    Nordström, A C; Jacobs, F A; Eliasson, L

    1991-07-01

    The influence of exogenous indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on the internal levels of these auxins was studied during the first 4 days of adventitious root formation in cuttings of Pisum sativum L. The quantitations were done by high performance liquid chromatography with spectrofluorometric detection. IBA, identified by combined gas chromatography-mass spectrometry (GC-MS), was found to naturally occur in this plant material. The root inducing ability of exogenous IBA was superior to that of IAA. The IAA level in the tissue increased considerably on the first day after application of IAA, but rapidly decreased again, returning to a level twice the control by day 3. The predominant metabolic route was conjugation with aspartic acid, as reflected by the increase in the level of indole-3-acetylaspartic acid. The IBA treatment resulted in increases in the levels of IBA, IAA, and indole-3-acetylaspartic acid. The IAA content rapidly returned to control levels, whereas the IBA level remained high throughout the experimental period. High amounts of indole-3-butyrylaspartic acid were found in the tissue after feeding with IBA. The identity of the conjugate was confirmed by (1)H-nuclear magnetic resonance and GC-MS. IBA was much more stable in solution than IAA. No IAA was detected after 48 hours, whereas 70% IBA was still recovered after this time. The relatively higher root inducing ability of IBA is ascribed to the fact that its level remained elevated longer than that of IAA, even though IBA was metabolized in the tissue. Adventitious root formation is discussed on the basis of these findings. PMID:16668265

  16. Studies on the hormonal relationships of algae in pure culture : I. The effect of indole-3-acetic acid on the growth of blue-green and green algae.

    PubMed

    Ahmad, M R; Winter, A

    1968-09-01

    Indole-3-acetic acid (IAA) stimulated the growth (increase in dry weight) of the blue-green algae Anacystis nidulans, Chlorogloea fritschii, Phormidium foveolarum, Nostoc muscorum, Anabaena cylindrica, and Tolypothrix tenuis and the green algae Chlorella pyrenoidosa, Ankistrodesmus falcatus and Scenedesmus obliquus growing under as sterile conditions as possible. The optimum concentration varied from species to species; in the blue-green algae it ranged from 10(-5) to 10(-9) M and in the green algae it was 10(-3) M. These results are discussed in the light of present studies in this field. PMID:24522736

  17. Characterization of a Nitrilase and a Nitrile Hydratase from Pseudomonas sp. Strain UW4 That Converts Indole-3-Acetonitrile to Indole-3-Acetic Acid

    PubMed Central

    Rose, David R.; Glick, Bernard R.

    2014-01-01

    Indole-3-acetic acid (IAA) is a fundamental phytohormone with the ability to control many aspects of plant growth and development. Pseudomonas sp. strain UW4 is a rhizospheric plant growth-promoting bacterium that produces and secretes IAA. While several putative IAA biosynthetic genes have been reported in this bacterium, the pathways leading to the production of IAA in strain UW4 are unclear. Here, the presence of the indole-3-acetamide (IAM) and indole-3-acetaldoxime/indole-3-acetonitrile (IAOx/IAN) pathways of IAA biosynthesis is described, and the specific role of two of the enzymes (nitrilase and nitrile hydratase) that mediate these pathways is assessed. The genes encoding these two enzymes were expressed in Escherichia coli, and the enzymes were isolated and characterized. Substrate-feeding assays indicate that the nitrilase produces both IAM and IAA from the IAN substrate, while the nitrile hydratase only produces IAM. The two nitrile-hydrolyzing enzymes have very different temperature and pH optimums. Nitrilase prefers a temperature of 50°C and a pH of 6, while nitrile hydratase prefers 4°C and a pH of 7.5. Based on multiple sequence alignments and motif analyses, physicochemical properties and enzyme assays, it is concluded that the UW4 nitrilase has an aromatic substrate specificity. The nitrile hydratase is identified as an iron-type metalloenzyme that does not require the help of a P47K activator protein to be active. These data are interpreted in terms of a preliminary model for the biosynthesis of IAA in this bacterium. PMID:24837382

  18. Enterococcus faecium LKE12 Cell-Free Extract Accelerates Host Plant Growth via Gibberellin and Indole-3-Acetic Acid Secretion.

    PubMed

    Lee, Ko-Eun; Radhakrishnan, Ramalingam; Kang, Sang-Mo; You, Young-Hyun; Joo, Gil-Jae; Lee, In-Jung; Ko, Jae-Hwan; Kim, Jin-Ho

    2015-09-01

    The use of microbial extracts containing plant hormones is a promising technique to improve crop growth. Little is known about the effect of bacterial cell-free extracts on plant growth promotion. This study, based on phytohormonal analyses, aimed at exploring the potential mechanisms by which Enterococcus faecium LKE12 enhances plant growth in oriental melon. A bacterial strain, LKE12, was isolated from soil, and further identified as E. faecium by 16S rDNA sequencing and phylogenetic analysis. The plant growth-promoting ability of an LKE12 bacterial culture was tested in a gibberellin (GA)-deficient rice dwarf mutant (waito-C) and a normal GA biosynthesis rice cultivar (Hwayongbyeo). E. faecium LKE12 significantly improved the length and biomass of rice shoots in both normal and dwarf cultivars through the secretion of an array of gibberellins (GA1, GA3, GA7, GA8, GA9, GA12, GA19, GA20, GA24, and GA53), as well as indole-3-acetic acid (IAA). To the best of our knowledge, this is the first study indicating that E. faecium can produce GAs. Increases in shoot and root lengths, plant fresh weight, and chlorophyll content promoted by E. faecium LKE12 and its cell-free extract inoculated in oriental melon plants revealed a favorable interaction of E. faecium LKE12 with plants. Higher plant growth rates and nutrient contents of magnesium, calcium, sodium, iron, manganese, silicon, zinc, and nitrogen were found in cell-free extract-treated plants than in control plants. The results of the current study suggest that E. faecium LKE12 promotes plant growth by producing GAs and IAA; interestingly, the exogenous application of its cell-free culture extract can be a potential strategy to accelerate plant growth. PMID:25907061

  19. Indole-3-acetic acid biosensor based on G-rich DNA labeled AuNPs as chemiluminescence probe coupling the DNA signal amplification

    NASA Astrophysics Data System (ADS)

    Hun, Xu; Mei, Zhenghua; Wang, Zhouping; He, Yunhua

    2012-09-01

    A highly sensitive chemiluminescence (CL) method for detection of phytohormone indole-3-acetic acid (IAA) was developed by using G-rich DNA labeled gold nanoparticles (AuNPs) as CL probe coupling the DNA signal amplification technology. The IAA antibody was immobilized on carboxyl terminated magnetic beads (MBs). In the presence of IAA, antibody labeled AuNPs were captured by antibody functionalized MBs. The DNA on AuNPs is released by a ligand exchange process induced by the addition of DTT. The released DNA is then acted as the linker and hybridized with the capture DNA on MBs and probe DNA on AuNPs CL probe. The CL signal is obtained via the instantaneous derivatization reaction between a specific CL reagent, 3,4,5-trimethoxyl-phenylglyoxal (TMPG), and the G-rich DNA on AuNPs CL probe. IAA can be detected in the concentration range from 0.02 ng/mL to 30 ng/mL, and the limit of detection is 0.01 ng/mL.

  20. The involvement of indole-3-acetic acid in the control of stem elongation in dark- and light-grown pea (Pisum sativum) seedlings.

    PubMed

    Sorce, Carlo; Picciarelli, Piero; Calistri, Gianni; Lercari, Bartolomeo; Ceccarelli, Nello

    2008-01-01

    We investigated the role of auxin on stem elongation in pea (Pisum sativum L.) grown for 10d in continuous darkness or under low-irradiance blue, red, far red and white light. The third internode of treated seedlings was peeled and the tissues (epidermis and cortex+central cylinder) were separately analyzed for the concentration of free and conjugated indole-3-acetic acid (IAA). Under red, far red and white light internode elongation was linearly related with the free IAA content of all internode tissues, suggesting that phytochrome-dependent inhibition of stem growth may be mediated by a decrease of free IAA levels in pea seedlings. The correlation between IAA and internode elongation, however, did not hold for blue light-grown seedlings. The hypothesis that the growth response under low-irradiance blue light might be correlated with the lack of phytochrome B signalling and changes in gibberellin metabolism is discussed in view of current knowledge on hormonal control of stem growth. PMID:17706834

  1. Pseudomonas induces salinity tolerance in cotton (Gossypium hirsutum) and resistance to Fusarium root rot through the modulation of indole-3-acetic acid

    PubMed Central

    Egamberdieva, Dilfuza; Jabborova, Dilfuza; Hashem, Abeer

    2015-01-01

    Abiotic stresses cause changes in the balance of phytohormones in plants and result in inhibited root growth and an increase in the susceptibility of plants to root rot disease. The aim of this work was to ascertain whether microbial indole-3-acetic acid (IAA) plays a role in the regulation of root growth and microbially mediated control of root rot of cotton caused by Fusarium solani. Seed germination and seedling growth were improved by both NaCl and Mg2SO4 (100 mM) solutions when treated with root-associated bacterial strains Pseudomonas putida R4 and Pseudomonas chlororaphis R5, which are able to produce IAA. These bacterial strains were also able to reduce the infection rate of cotton root rot (from 70 to 39%) caused by F. solani under gnotobiotic conditions. The application of a low concentration of IAA (0.01 and 0.001 μg/ml) stimulated plant growth and reduced disease incidence caused by F. solani (from 70 to 41–56%, respectively). Shoot and root growth and dry matter increased significantly and disease incidence was reduced by bacterial inoculants in natural saline soil. These results suggest that bacterial IAA plays a major role in salt stress tolerance and may be involved in induced resistance against root rot disease of cotton. PMID:26587006

  2. Indole-3-acetic acid biosynthetic pathway and aromatic amino acid aminotransferase activities in Pantoea dispersa strain GPK.

    PubMed

    Kulkarni, G B; Nayak, A S; Sajjan, S S; Oblesha, A; Karegoudar, T B

    2013-05-01

    This investigation deals with the production of IAA by a bacterial isolate Pantoea dispersa strain GPK (PDG) identified by 16S rRNA gene sequence analysis. HPLC and Mass spectral analysis of metabolites from bacterial spent medium revealed that, IAA production by PDG is Trp-dependent and follows indole-3-pyruvic acid (IPyA) pathway. Substrate specificity study of aromatic amino acid aminotransferase (AAT) showed high activities, only when tryptophan (Trp) and α-ketoglutarate (α-kg) were used as substrates. AAT is highly specific for Trp and α-kg as amino group donor and acceptor, respectively. The effect of exogenous IAA on bacterial growth was established. Low concentration of exogenous IAA induced the growth, whereas high concentration decreased the growth of bacterium. PDG treatment significantly increased the root length, shoot length and dry mass of the chickpea and pigeon pea plants. PMID:23448265

  3. Ultrasensitive photoelectrochemical immunoassay of indole-3-acetic acid based on the MPA modified CdS/RGO nanocomposites decorated ITO electrode.

    PubMed

    Sun, Bing; Chen, Lijian; Xu, Yan; Liu, Min; Yin, Huanshun; Ai, Shiyun

    2014-01-15

    A novel ultrasensitive photoelectrochemical immunosensor was fabricated based on 3-mercaptopropionic acid stabilized CdS/reduced graphene oxide (MPA-CdS/RGO) nanocomposites for indole-3-acetic acid (IAA) detection. The MPA-CdS/RGO nanocomposites were synthesized by in situ solvothermal growth of triangulated pyramidal CdS nanoparticles on the RGO sheet. 3-Mercaptopropionic acid (MPA) was employed as the modifier and bridge to immobilize the antibody. The nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and UV/vis spectra. The results showed that the MPA-CdS/RGO nanocomposites revealed enhanced photocurrent response due to excellent electron transport properties of RGO and the improved assembly of CdS nanoparticles onto RGO sheet with the introduction of MPA. Based on the dependence of the photocurrent decline on the concentration of IAA, the proposed photoelectrochemical immunosensor for IAA depicted a linear range from 0.1 to 1000 ng/mL with a lower detection limit (0.05 ng/mL). The high sensitivity, reproducibility and specificity of the method permitted the method suitable to be used in real samples. PMID:23954674

  4. Effect of K+ and Ca2+ on the indole-3-acetic acid- and fusicoccin-induced growth and membrane potential in maize coleoptile cells

    PubMed Central

    Siemieniuk, Agnieszka; Karcz, Waldemar

    2015-01-01

    The role of potassium (K+) and calcium (Ca2+) in the regulation of plant growth and development is complex and needs a diverse range of physiological studies. Both elements are essential for satisfactory crop production. Here, the effects of K+ and Ca2+ ions on endogenous growth and growth in the presence of either indole-3-acetic acid (IAA) or fusicoccin (FC) were studied in maize (Zea mays) coleoptiles. Membrane potentials of coleoptile parenchymal cells, incubated in media containing IAA, FC and different concentrations of K+ and Ca2+, were also determined. Growth experiments have shown that in the absence of K+ in the incubation medium, both endogenous and IAA- or FC-induced growth were significantly inhibited by 0.1 and 1 mM Ca2+, respectively, while in the presence of 1 mM K+ they were inhibited only by 1 mM Ca2+. At 10 mM K+, endogenous growth and growth induced by either IAA or FC did not depend on Ca2+ concentration. TEA-Cl, a potassium channel blocker, added 1 h before IAA or FC, caused a reduction of growth by 59 or 45 %, respectively. In contrast to TEA-Cl, verapamil, the Ca2+ channel blocker, did not affect IAA- and FC-induced growth. It was also found that in parenchymal cells of maize coleoptile segments, membrane potential (Em) was strongly affected by the medium K+, independently of Ca2+. However, lack of Ca2+ in the incubation medium significantly reduced the IAA- and FC-induced membrane potential hyperpolarization. TEA-Cl applied to the control medium in the same way as in growth experiments caused Em hyperpolarization synergistic with hyperpolarization produced by IAA or FC. Verapamil did not change either the Em of parenchymal cells incubated in the control medium or the IAA- and FC-induced membrane hyperpolarization. The data presented here have been discussed considering the role of K+ uptake channels in regulation of plant cell growth. PMID:26134122

  5. Effect of K+ and Ca2+ on the indole-3-acetic acid- and fusicoccin-induced growth and membrane potential in maize coleoptile cells.

    PubMed

    Siemieniuk, Agnieszka; Karcz, Waldemar

    2015-01-01

    The role of potassium (K(+)) and calcium (Ca(2+)) in the regulation of plant growth and development is complex and needs a diverse range of physiological studies. Both elements are essential for satisfactory crop production. Here, the effects of K(+) and Ca(2+) ions on endogenous growth and growth in the presence of either indole-3-acetic acid (IAA) or fusicoccin (FC) were studied in maize (Zea mays) coleoptiles. Membrane potentials of coleoptile parenchymal cells, incubated in media containing IAA, FC and different concentrations of K(+) and Ca(2+), were also determined. Growth experiments have shown that in the absence of K(+) in the incubation medium, both endogenous and IAA- or FC-induced growth were significantly inhibited by 0.1 and 1 mM Ca(2+), respectively, while in the presence of 1 mM K(+) they were inhibited only by 1 mM Ca(2+). At 10 mM K(+), endogenous growth and growth induced by either IAA or FC did not depend on Ca(2+) concentration. TEA-Cl, a potassium channel blocker, added 1 h before IAA or FC, caused a reduction of growth by 59 or 45 %, respectively. In contrast to TEA-Cl, verapamil, the Ca(2+) channel blocker, did not affect IAA- and FC-induced growth. It was also found that in parenchymal cells of maize coleoptile segments, membrane potential (Em) was strongly affected by the medium K(+), independently of Ca(2+). However, lack of Ca(2+) in the incubation medium significantly reduced the IAA- and FC-induced membrane potential hyperpolarization. TEA-Cl applied to the control medium in the same way as in growth experiments caused Em hyperpolarization synergistic with hyperpolarization produced by IAA or FC. Verapamil did not change either the Em of parenchymal cells incubated in the control medium or the IAA- and FC-induced membrane hyperpolarization. The data presented here have been discussed considering the role of K(+) uptake channels in regulation of plant cell growth. PMID:26134122

  6. Differential regulation of genes encoding 1-aminocyclopropane-1-carboxylate (ACC) synthase in etiolated pea seedlings: effects of indole-3-acetic acid, wounding, and ethylene.

    PubMed

    Peck, S C; Kende, H

    1998-12-01

    Treatment of 5- to 6-day-old etiolated pea (Pisum sativum L.) seedlings with indole-3-acetic acid (IAA) induced within 15 min an increase in the transcript levels of two genes encoding 1-aminocyclopropane-1-carboxylate (ACC) synthase, Ps-ACS1 and Ps-ACS2. Simultaneous treatment with ethylene inhibited this increase and also caused a decrease in ACC synthase enzyme activity as compared to that of seedlings treated with IAA alone. These results indicate that ethylene inhibits its own biosynthesis by decreasing ACC synthase transcript levels via a negative feedback loop. Wounding of pea stems had no effect on the expression of Ps-ACS1, but led within 10 min to an increase in the mRNA levels of Ps-ACS2. This increase was also inhibited by ethylene. The wound signal was transmitted over a distance of at least 4 cm through the stem with no delay in induction or response intensity. The rapid transmission of the wound response is consistent with the possibility that a hydraulic or electric signal is responsible for the spread of the wound response. PMID:9869404

  7. Indole-3-acetic acid UDP-glucosyltransferase from immature seeds of pea is involved in modification of glycoproteins.

    PubMed

    Ostrowski, Maciej; Hetmann, Anna; Jakubowska, Anna

    2015-09-01

    The glycosylation of auxin is one of mechanisms contributing to hormonal homeostasis. The enzyme UDPG: indole-3-ylacetyl-β-D-glucosyltransferase (IAA glucosyltransferase, IAGlc synthase) catalyzes the reversible reaction: IAA+UDPG↔1-O-IA-glucose+UDP, which is the first step in the biosynthesis of IAA-ester conjugates in monocotyledonous plants. In this study, we report IAA-glucosyltransferase isolated using a biochemical approach from immature seed of pea (Pisum sativum). The enzyme was purified by PEG fractionation, DEAE-Sephacel anion-exchange chromatography and preparative PAGE. LC-MS/MS analysis of tryptic peptides of the enzyme revealed the high identity with maize IAGlc synthase, but lack of homology with other IAA-glucosyltransferases from dicots. Biochemical characterization showed that of several acyl acceptors tested, the enzyme had the highest activity on IAA as the glucosyl acceptor (Km=0.52 mM, Vmax=161 nmol min(-1), kcat/Km=4.36 mM s(-1)) and lower activity on indole-3-propionic acid and 1-naphthalene acetic acid. Whereas indole-3-butyric acid and indole-3-propionic acid were competitive inhibitors of IAGlc synthase, D-gluconic acid lactone, an inhibitor of β-glucosidase activity, potentiated the enzyme activity at the optimal concentration of 0.3mM. Moreover, we demonstrated that the 1-O-IA-glucose synthesized by IAGlc synthase is the substrate for IAA labeling of glycoproteins from pea seeds indicating a possible role of this enzyme in the covalent modification of a class of proteins by a plant hormone. PMID:26057226

  8. Production of Indole-3-Acetic Acid via the Indole-3-Acetamide Pathway in the Plant-Beneficial Bacterium Pseudomonas chlororaphis O6 Is Inhibited by ZnO Nanoparticles but Enhanced by CuO Nanoparticles

    PubMed Central

    Zeng, Jia; McLean, Joan E.; Britt, David W.; Zhan, Jixun; Anderson, Anne J.

    2012-01-01

    The beneficial bacterium Pseudomonas chlororaphis O6 produces indole-3-acetic acid (IAA), a plant growth regulator. However, the pathway involved in IAA production in this bacterium has not been reported. In this paper we describe the involvement of the indole-3-acetamide (IAM) pathway in IAA production in P. chlororaphis O6 and the effects of CuO and ZnO nanoparticles (NPs). Sublethal levels of CuO and ZnO NPs differentially affected the levels of IAA secreted in medium containing tryptophan as the precursor. After 15 h of growth, CuO NP-exposed cells had metabolized more tryptophan than the control and ZnO NP-challenged cells. The CuO NP-treated cells produced higher IAA levels than control cultures lacking NPs. In contrast, ZnO NPs inhibited IAA production. Mixing of CuO and ZnO NPs resulted in an intermediate level of IAA production relative to the levels in the separate CuO and ZnO NP treatments. The effect of CuO NPs on IAA levels could be duplicated by ions at the concentrations released from the NPs. However, ion release did not account for the inhibition caused by the ZnO NPs. The mechanism underlying changes in IAA levels cannot be accounted for by effects on transcript accumulation from genes encoding a tryptophan permease or the IAM hydrolase in 15-h cultures. These findings raise the issue of whether sublethal doses of NPs would modify the beneficial effects of association between plants and bacteria. PMID:22210218

  9. Structural, Biochemical, and Phylogenetic Analyses Suggest That Indole-3-Acetic Acid Methyltransferase Is an Evolutionarily Ancient Member of the SABATH Family1[W][OA

    PubMed Central

    Zhao, Nan; Ferrer, Jean-Luc; Ross, Jeannine; Guan, Ju; Yang, Yue; Pichersky, Eran; Noel, Joseph P.; Chen, Feng

    2008-01-01

    The plant SABATH protein family encompasses a group of related small-molecule methyltransferases (MTs) that catalyze the S-adenosyl-l-methionine-dependent methylation of natural chemicals encompassing widely divergent structures. Indole-3-acetic acid (IAA) methyltransferase (IAMT) is a member of the SABATH family that modulates IAA homeostasis in plant tissues through methylation of IAA's free carboxyl group. The crystal structure of Arabidopsis (Arabidopsis thaliana) IAMT (AtIAMT1) was determined and refined to 2.75 Å resolution. The overall tertiary and quaternary structures closely resemble the two-domain bilobed monomer and the dimeric arrangement, respectively, previously observed for the related salicylic acid carboxyl methyltransferase from Clarkia breweri (CbSAMT). To further our understanding of the biological function and evolution of SABATHs, especially of IAMT, we analyzed the SABATH gene family in the rice (Oryza sativa) genome. Forty-one OsSABATH genes were identified. Expression analysis showed that more than one-half of the OsSABATH genes were transcribed in one or multiple organs. The OsSABATH gene most similar to AtIAMT1 is OsSABATH4. Escherichia coli-expressed OsSABATH4 protein displayed the highest level of catalytic activity toward IAA and was therefore named OsIAMT1. OsIAMT1 exhibited kinetic properties similar to AtIAMT1 and poplar IAMT (PtIAMT1). Structural modeling of OsIAMT1 and PtIAMT1 using the experimentally determined structure of AtIAMT1 reported here as a template revealed conserved structural features of IAMTs within the active-site cavity that are divergent from functionally distinct members of the SABATH family, such as CbSAMT. Phylogenetic analysis revealed that IAMTs from Arabidopsis, rice, and poplar (Populus spp.) form a monophyletic group. Thus, structural, biochemical, and phylogenetic evidence supports the hypothesis that IAMT is an evolutionarily ancient member of the SABATH family likely to play a critical role in IAA

  10. Structural, Biochemical, and Phylogenetic Analyses Suggest That Indole-3-Acetic Acid Methyltransferase Is an Evolutionarily Ancient Member of the SABATH Family

    SciTech Connect

    Zhao,N.; Ferrer, J.; Ross, J.; Guan, J.; Yang, Y.; Pichersky, E.; Noel, J.; Chen, F.

    2008-01-01

    The plant SABATH protein family encompasses a group of related small-molecule methyltransferases (MTs) that catalyze the S-adenosyl-L-methionine-dependent methylation of natural chemicals encompassing widely divergent structures. Indole-3-acetic acid (IAA) methyltransferase (IAMT) is a member of the SABATH family that modulates IAA homeostasis in plant tissues through methylation of IAA's free carboxyl group. The crystal structure of Arabidopsis (Arabidopsis thaliana) IAMT (AtIAMT1) was determined and refined to 2.75 Angstroms resolution. The overall tertiary and quaternary structures closely resemble the two-domain bilobed monomer and the dimeric arrangement, respectively, previously observed for the related salicylic acid carboxyl methyltransferase from Clarkia breweri (CbSAMT). To further our understanding of the biological function and evolution of SABATHs, especially of IAMT, we analyzed the SABATH gene family in the rice (Oryza sativa) genome. Forty-one OsSABATH genes were identified. Expression analysis showed that more than one-half of the OsSABATH genes were transcribed in one or multiple organs. The OsSABATH gene most similar to AtIAMT1 is OsSABATH4. Escherichia coli-expressed OsSABATH4 protein displayed the highest level of catalytic activity toward IAA and was therefore named OsIAMT1. OsIAMT1 exhibited kinetic properties similar to AtIAMT1 and poplar IAMT (PtIAMT1). Structural modeling of OsIAMT1 and PtIAMT1 using the experimentally determined structure of AtIAMT1 reported here as a template revealed conserved structural features of IAMTs within the active-site cavity that are divergent from functionally distinct members of the SABATH family, such as CbSAMT. Phylogenetic analysis revealed that IAMTs from Arabidopsis, rice, and poplar (Populus spp.) form a monophyletic group. Thus, structural, biochemical, and phylogenetic evidence supports the hypothesis that IAMT is an evolutionarily ancient member of the SABATH family likely to play a critical role in

  11. Myo-inositol esters of indole-3-acetic acid are endogenous components of Zea mays L. shoot tissue

    NASA Technical Reports Server (NTRS)

    Chisnell, J. R.

    1984-01-01

    Indole-3-acetyl-myo-inositol esters have been demonstrated to be endogenous components of etiolated Zea mays shoots tissue. This was accomplished by comparison of the putative compounds with authentic, synthetic esters. The properties compared were liquid and gas-liquid chromatographic retention times and the 70-ev mass spectral fragmentation pattern of the pentaacetyl derivative. The amount of indole-3-acetyl-myo-inositol esters in the shoots was determined to be 74 nanomoles per kilogram fresh weight as measured by isotope dilution, accounting for 19% of the ester indole-3-acetic acid of the shoot. This work is the first characterization of an ester conjugate of indole-3-acetate acid from vegetative shoot tissue using multiple chromatographic properties and mass spectral identification. The kernel and the seedling shoot both contain indole-3-acetyl-myo-inositol esters, and these esters comprise approximately the same percentage of the total ester content of the kernel and of the shoot.

  12. Synthesis of new chalcone derivatives containing a rhodanine-3-acetic acid moiety with potential anti-bacterial activity.

    PubMed

    Chen, Zhen-Hua; Zheng, Chang-Ji; Sun, Liang-Peng; Piao, Hu-Ri

    2010-12-01

    With an intention to synergize the anti-bacterial activity of chalcones and rhodanine-3-acetic acid, several hybrid compounds possessing chalcone and rhodanine-3-acetic acid moieties were synthesized and tested for their anti-bacterial activity. Some compounds presented great anti-microbial activities against Gram-positive bacteria (including the multidrug-resistant clinical isolates). This class of compounds presented high potency against Staphylococcus aureus, among which the derivatives 5k with a MIC of 2 μg/mL was as active as the standard drug (norfloxacin) and less active than oxacillin. Compounds 5a-s did not inhibit the growth of Gram-negative bacteria Escherichia coli CCARM 1924 or E. coli CCARM 1356 at 64 μg/mL. PMID:20889240

  13. Effect of indole-3-acetic acid (plant auxin) on the preservation at 15 degrees C of boar semen for artificial insemination.

    PubMed

    Toniolli, R; Bussière, J; Courot, M; Magistrini, M; Combarnous, Y

    1996-01-01

    In order to extend the duration of boar sperm survival at 15 degrees C for artificial insemination, we tested the effect of indole-3-acetic acid (IAA), which appeared to be the main sperm protective substance present in the Coco nucifera endosperm (coconut water). Two IAA concentrations (10 and 100 ng/mL) in Beltsville extender (BTS) were studied for their in vitro effects. The motility, the percentage of motile spermatozoa and the acrosome morphology of sperm were recorded each day over 13 days of storage at 15 degrees C, after 5 min and 3 h of incubation at 39 degrees C. The IAA effect on sperm preservation was also studied in vivo at a concentration of 10 ng/mL in BTS by inseminating groups of females twice at 24 h intervals either at D0 (day of sperm collection) and D1 (D0/1) or at D5 and D6 (D5/6). At D0/1, the two groups of females (control and IAA) were inseminated with a total of 6.3 x 10(9) spermatozoa (3.15 x 10(9) at D0 and the same dose at D1) whereas at D5/6, on IAA group was inseminated with a total of 6.3 x 10(9) spermatozoa and another one with 12.6 x 10(9) spermatozoa. The animals in the D5/6 control group were inseminated each with a total of 12.6 x 10(9) spermatozoa. For each group of females (n = 106-140), fertility rate (% farrowing) and prolificacy rate (litter size) were recorded. No effect of IAA in vitro on the motility rate and on the percentage of motile spermatozoa was observed over a 13 day storage. However, IAA (10 ng/mL) had a significant positive effect on the percentage of living spermatozoa with intact acrosomes after 13 days (66 vs 54%, P < 0.05). The fertility and prolificacy rates after 5-6 days of sperm preservation in BTS extender alone did not differ significantly between D5/6 and D0/1 but the total number of inseminated spermatozoa was 12.6 x 10(9) at D5/6 instead of 6.3 x 10(9) at D0/1. When the spermatozoa were stored in the presence of 10 ng/mL IAA for 5-6 days at 15 degrees C, the fertility and prolificacy of the females

  14. Studies on the growth and indole-3-acetic acid and abscisic acid content of Zea mays seedlings grown in microgravity

    NASA Technical Reports Server (NTRS)

    Schulze, A.; Jensen, P. J.; Desrosiers, M.; Buta, J. G.; Bandurski, R. S.

    1992-01-01

    Measurements were made of the fresh weight, dry weight, dry weight-fresh weight ratio, free and conjugated indole-3-acetic acid, and free and conjugated abscisic acid in seedlings of Zea mays grown in darkness in microgravity and on earth. Imbibition of the dry kernels was 17 h prior to launch. Growth was for 5 d at ambient orbiter temperature and at a chronic accelerational force of the order of 3 x 10(-5) times earth gravity. Weights and hormone content of the microgravity seedlings were, with minor exceptions, not statistically different from seedlings grown in normal gravity. The tissues of the shuttle-grown plants appeared normal and the seedlings differed only in the lack of orientation of roots and shoots. These findings, based upon 5 d of growth in microgravity, cannot be extrapolated to growth in microgravity for weeks, months, and years, as might occur on a space station. Nonetheless, it is encouraging, for prospects of bioregeneration of the atmosphere and food production in a space station, that no pronounced differences in the parameters measured were apparent during the 5 d of plant seedling growth in microgravity.

  15. Epibrassinolide ameliorates Cr (VI) stress via influencing the levels of indole-3-acetic acid, abscisic acid, polyamines and antioxidant system of radish seedlings.

    PubMed

    Choudhary, Sikander Pal; Kanwar, Mukesh; Bhardwaj, Renu; Gupta, B D; Gupta, R K

    2011-07-01

    The present investigation determined the effects of epibrassinolide (EBL) on the levels of indole-3-acetic acid (IAA), abscisic acid (ABA), and polyamine (PA) and antioxidant potential of 7-d old Raphanus sativus L. cv. 'Pusa chetki' seedlings grown under Cr (VI) metal stress. Reduced titers of free (0.767 μg g(-1) FW) and bound (0.545 μg g(-1) FW) IAA in Cr (VI) stressed seedlings were observed over untreated control. Supplementations of EBL to Cr (VI) stressed seedlings were able to enhance both free (2.14-5.68 μg g(-1) FW) and bound IAA (2.45-7.78 μg g(-1) FW) concentrations in comparison to Cr (VI) metal treatment alone. Significant rise in free (13.49 μg g(-1) FW) and bound (12.17 μg g(-1) FW) ABA contents were noticed for Cr (VI) stressed seedlings when compared to untreated control. No significant increase in ABA contents were recorded for Cr (VI) stressed seedlings upon supplementation with EBL over Cr (VI) treatment alone. A significant increase in Put (18.40 μg g(-1) FW) and Cad (9.08 μg g(-1) FW) contents were found for 10(-9)M EBL plus Cr (VI) metal treatments when compared to Cr (VI) treatment alone. Spermidine (Spd) contents were found to decline significantly for EBL treatment alone or when supplemented with Cr (VI) treatments over untreated controls and Cr (VI) treatment alone. Antioxidant levels were found to enhance, with glutathione (57.98 mg g(-1) FW), proline (4.97 mg g(-1) FW), glycinebetaine (39.01 μmol mL(-1)), ascorbic acid (3.17 mg g(-1) FW) and phytochelatins (65.69 μmol g(-1) FW) contents noted for EBL supplemented to Cr (VI) metal solution over Cr (VI) treatment alone. Reduced activities of guaiacol peroxidase (0.391 U mg(-1) protein) and catalase (0.221 U mg(-1) protein) and enhanced activities of glutathione reductase (7.14 U mg(-1) protein), superoxide dismutase (15.20 U mg(-1) protein) and ascorbate peroxidase (4.31 U mg(-1) protein) were observed in seedlings treated with EBL plus Cr (VI) over Cr metal treatment alone

  16. Oligo-carrageenan kappa-induced reducing redox status and activation of TRR/TRX system increase the level of indole-3-acetic acid, gibberellin A3 and trans-zeatin in Eucalyptus globulus trees.

    PubMed

    González, Alberto; Contreras, Rodrigo A; Zúiga, Gustavo; Moenne, Alejandra

    2014-01-01

    Eucalyptus globulus trees treated with oligo-carrageenan (OC) kappa showed an increase in NADPH, ascorbate and glutathione levels and activation of the thioredoxin reductase (TRR)/thioredoxin (TRX) system which enhance photosynthesis, basal metabolism and growth. In order to analyze whether the reducing redox status and the activation of thioredoxin reductase (TRR)/thioredoxin (TRX) increased the level of growth-promoting hormones, trees were treated with water (control), with OC kappa, or with inhibitors of ascorbate synthesis, lycorine, glutathione synthesis, buthionine sulfoximine (BSO), NADPH synthesis, CHS-828, and thioredoxin reductase activity, auranofine, and with OC kappa, and cultivated for four additional months. Eucalyptus trees treated with OC kappa showed an increase in the levels of the auxin indole 3-acetic acid (IAA), gibberellin A3 (GA3) and the cytokinin trans-zeatin (t-Z) as well as a decrease in the level of the brassinosteroid epi-brassinolide (EB). In addition, treatment with lycorine, BSO, CHS-828 and auranofine inhibited the increase in IAA, GA3 and t-Z as well as the decrease in EB levels. Thus, the reducing redox status and the activation of TRR/TRX system induced by OC kappa increased the levels of IAA, GA3 and t-Z levels determining, at least in part, the stimulation of growth in Eucalyptus trees. PMID:25140447

  17. Crystal structure of 3-acet-oxy-2-methyl-benzoic acid.

    PubMed

    Saranya, Matheswaran; Subashini, Annamalai; Arunagiri, Chidambaram; Muthiah, Packianathan Thomas

    2015-07-01

    In the title mol-ecule, C10H10O4, the carb-oxy-lic acid group is twisted by 11.37 (15)° from the plane of the benzene ring and the acet-oxy group is twisted from this plane by 86.60 (17)°. In the crystal, mol-ecules are linked by pairs of O-H⋯O hydrogen bonds, forming inversion dimers with the expected R 2 (2)(8) graph-set motif. PMID:26279915

  18. A gain-of-function mutation in IAA8 alters Arabidopsis floral organ development by change of jasmonic acid level.

    PubMed

    Wang, Jing; Yan, Da-Wei; Yuan, Ting-Ting; Gao, Xiang; Lu, Ying-Tang

    2013-05-01

    Auxin regulates a variety of physiological processes via its downstream factors included Aux/IAAs. In this study, one of these Aux/IAAs, IAA8 is shown to play its role in Arabidopsis development with transgenic plants expressing GFP-mIAA8 under the control of IAA8 promoter, in which IAA8 protein was mutated by changing Pro170 to Leu170 in its conserved domain II. These transgenic dwarfed plants had more lateral branches, short primary inflorescence stems, decreased shoot apical dominance, curled leaves and abnormal flower organs (short petal and stamen, and bent stigmas). Further experiments revealed that IAA8::GFP-mIAA8 plants functioned as gain-of-function mutation to increase GFP-mIAA8 amount probably by stabilizing IAA8 protein against proteasome-mediated protein degradation with IAA8::GFP-IAA8 plants as control. The searching for its downstream factors indicated its interaction with both ARF6 and ARF8, suggesting that IAA8 may involve in flower organ development. This was further evidenced by analyzing the expression of jasmonic acid (JA) biosynthetic genes and JA levels because ARF6 and ARF8 are required for normal JA production. These results indicated that in IAA8::GFP-mIAA8 plants, JA biosynthetic genes including DAD1 (AT2G44810), AOS (AT5G42650) and ORP3 (AT2G06050) were dramatically down-regulated and JA level in the flowers was reduced to 70 % of that in wild-type. Furthermore, exogenous JA application can partially rescue short petal and stamen observed IAA8::GFP-mIAA8 plants. Thus, IAA8 plays its role in floral organ development by changes in JA levels probably via its interaction with ARF6/8 proteins. PMID:23483289

  19. A new titanium biofunctionalized interface based on poly(pyrrole-3-acetic acid) coating: proliferation of osteoblast-like cells and future perspectives.

    PubMed

    De Giglio, Elvira; Cometa, Stefania; Calvano, Cosima-Damiana; Sabbatini, Luigia; Zambonin, Pier Giorgio; Colucci, Silvia; Benedetto, Adriana Di; Colaianni, Graziana

    2007-09-01

    In recent years, many procedures based on surface modification have been suggested to improve the biocompatibility and biofunctionality of orthopedic titanium-based implants. In this contest, the development of a new titanium-based biomaterial that could be covalently modified with biologically active molecules (i.e., RGD-peptides, growth factors, etc.) able to improve osteoblasts response was investigated. The strategy followed was based on a preliminary coating of the implant material by an adherent thin polymer film to which bioactive molecules could be grafted exploiting the polymer surface chemical reactivity. In this work, we focused our attention on pyrrole-3-acetic acid (Py-3-acetic), a pyrrole with carboxylic acid substituent, whose electrosynthesis and characterization on titanium substrates were already accomplished and whose potentialities in the design of new biocompatible surfaces are well evident. As first step, the biocompatibility of the electrochemically grown PPy-3-acetic films was investigated performing in vitro tests (adhesion and proliferation) with mouse bone marrow cells. Successively, the availability and reactivity of surface carboxylic groups were tested through the grafting of an aminoacidic residue to PPy-3-acetic films. PMID:17483896

  20. On the role of calcium in indole-3-acetic acid movement and graviresponse in etiolated pea epicotyls

    NASA Technical Reports Server (NTRS)

    Migliaccio, F.; Galston, A. W.

    1989-01-01

    To determine whether Ca2+ plays a special role in the early graviresponse of shoots, as has been reported for roots, we treated etiolated pea epicotyls with substances known to antagonize Ca2+ (La3+), to remove Ca2+ from the wall (spermidine, EGTA), to inhibit calmodulin mediated reactions (chlorpromazine), or to inhibit IAA transport (TIBA). We studied the effect of these substances on IAA and Ca2+ uptake into 7 mm long subapical 3rd internode etiolated pea epicotyl sections and pea leaf protoplasts, on pea epicotyl growth, and graviresponse and on lateral IAA redistribution during gravistimulation. Our results support the view that adequate Ca2+ in the apoplast is required for normal IAA uptake, transport and graviresponse. Experiments with protoplasts indicate that Ca2+ may be controlling a labile membrane porter, possibly located on the external surface of cell membrane, while inhibitor experiments suggest that calmodulin is also implicated in both the movement of IAA and graviresponse. Since a major transfer of Ca2+ through free space during graviresponse has not yet been demonstrated, and since inhibition of calcium channels does not affect IAA redistribution (Migliaccio and Galston, 1987, Plant Physiology 85:542), we conclude that no clear evidence links prior Ca2+ movement with IAA redistribution during graviresponse in stems.

  1. Preparation of magnetic indole-3-acetic acid imprinted polymer beads with 4-vinylpyridine and β-cyclodextrin as binary monomer via microwave heating initiated polymerization and their application to trace analysis of auxins in plant tissues.

    PubMed

    Zhang, Yi; Li, Yuanwen; Hu, Yuling; Li, Gongke; Chen, Yueqin

    2010-11-19

    Auxin is a crucial phytohormone for precise control of growth and development of plants. Due to its low concentration in plant tissues which are rich in interfering substances, the accurate determination of auxins remains a challenge. In this paper, a new strategy for isolation and enrichment of auxins from plant tissues was obtained by the magnetic molecularly imprinted polymer (mag-MIP) beads, which were prepared by microwave heating initiated suspension polymerization using indole-3-acetic acid (IAA) as template. In order to obtain higher selective recognition cavities, an enhanced imprinting method based on binary functional monomers, 4-vinylpyridine (4-VP) and β-cyclodextrin (β-CD), was adopted for IAA imprinting. The morphological and magnetic characteristics of the mag-MIP beads were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy and vibrating sample magnetometry. A majority of resultant beads were within the size range of 80-150μm. Porous surface morphology and good magnetic property were observed. Furthermore, the mag-MIP beads fabricated with 4-VP and β-CD as binary functional monomers exhibited improved recognition ability to IAA, as compared with the mag-MIP beads prepared with the individual monomer separately. Competitive rebinding experiment results revealed that the mag-MIP beads exhibited a higher specific recognition for the template than the non-imprinted polymer (mag-NIP) beads. An extraction method by mag-MIP beads coupled with high performance liquid chromatography (HPLC) was developed for determination of IAA and indole-3-butyric acid (IBA) in plant tissues. Linear ranges for IAA and IBA were in the range of 7.00-100.0μgL(-1) and 10.0-100.0μgL(-1), and the detection limits were 3.9 and 7.4μgL(-1), respectively. The analytical performance was also estimated by seedlings or immature embryos samples from three different plant tissues, pea, rice and wheat. Recoveries were in the range of 70

  2. Concurrent profiling of indole-3-acetic acid, abscisic acid, and cytokinins and structurally related purines by high-performance-liquid-chromatography tandem electrospray mass spectrometry

    PubMed Central

    2012-01-01

    Background Cytokinins (CKs) are a group of plant growth regulators that are involved in several plant developmental processes. Despite the breadth of knowledge surrounding CKs and their diverse functions, much remains to be discovered about the full potential of CKs, including their relationship with the purine salvage pathway, and other phytohormones. The most widely used approach to query unknown facets of CK biology utilized functional genomics coupled with CK metabolite assays and screening of CK associated phenotypes. There are numerous different types of assays for determining CK quantity, however, none of these methods screen for the compendium of metabolites that are necessary for elucidating all roles, including purine salvage pathway enzymes in CK metabolism, and CK cross-talk with other phytohormones. Furthermore, all published analytical methods have drawbacks ranging from the required use of radiolabelled compounds, or hazardous derivatization reagents, poor sensitivity, lack of resolution between CK isomers and lengthy run times. Results In this paper, a method is described for the concurrent extraction, purification and analysis of several CKs (freebases, ribosides, glucosides, nucleotides), purines (adenosine monophosphate, inosine, adenosine, and adenine), indole-3-acetic acid, and abscisic acid from hundred-milligram (mg) quantities of Arabidopsis thaliana leaf tissue. This method utilizes conventional Bieleski solvents extraction, solid phase purification, and is unique because of its diverse range of detectable analytes, and implementation of a conventional HPLC system with a fused core column that enables good sensitivity without the requirement of a UHPLC system. Using this method we were able to resolve CKs about twice as fast as our previous method. Similarly, analysis of adenosine, indole-3-acetic acid, and abscisic acid, was comparatively rapid. A further enhancement of the method was the utilization of a QTRAP 5500 mass analyzer, which

  3. Diversity of Stability, Localization, Interaction and Control of Downstream Gene Activity in the Maize Aux/IAA Protein Family

    PubMed Central

    Ludwig, Yvonne; Berendzen, Kenneth W.; Xu, Changzheng; Piepho, Hans-Peter; Hochholdinger, Frank

    2014-01-01

    AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins are central regulators of auxin signal transduction. They control many aspects of plant development, share a conserved domain structure and are localized in the nucleus. In the present study, five maize Aux/IAA proteins (ZmIAA2, ZmIAA11, ZmIAA15, ZmIAA20 and ZmIAA33) representing the evolutionary, phylogenetic and expression diversity of this gene family were characterized. Subcellular localization studies revealed that ZmIAA2, ZmIAA11 and ZmIAA15 are confined to the nucleus while ZmIAA20 and ZmIAA33 are localized in both the nucleus and the cytoplasm. Introduction of specific point mutations in the degron sequence (VGWPPV) of domain II by substituting the first proline by serine or the second proline by leucine stabilized the Aux/IAA proteins. While protein half-life times between ∼11 min (ZmIAA2) to ∼120 min (ZmIAA15) were observed in wild-type proteins, the mutated forms of all five proteins were almost as stable as GFP control proteins. Moreover, all five maize Aux/IAA proteins repressed downstream gene expression in luciferase assays to different degrees. In addition, bimolecular fluorescence complementation (BiFC) analyses demonstrated interaction of all five Aux/IAA proteins with RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1, ZmIAA10) while only ZmIAA15 and ZmIAA33 interacted with the RUM1 paralog RUL1 (RUM-LIKE 1, ZmIAA29). Moreover, ZmIAA11, ZmIAA15 ZmIAA33 displayed homotypic interaction. Hence, despite their conserved domain structure, maize Aux/IAA proteins display a significant variability in their molecular characteristics which is likely associated with the wide spectrum of their developmental functions. PMID:25203637

  4. Rapid Initiation of Thymidine Incorporation into Deoxyribonucleic Acid in Vegetative Tobacco Stem Segments Treated with Indole-3-acetic Acid 1

    PubMed Central

    Wardell, William L.

    1975-01-01

    The short term effect of 11.4 μm indoleacetic acid on the incorporation of (methyl-3H)thymidine into DNA in vegetative tobacco (Nicotiana tabacum cv. Wis. 38) stem segments has been investigated. In segments that are defoliated, inverted, and kept in the dark for 7 hours, indoleacetic acid very rapidly (about 60 minutes) and strikingly initiates thymidine incorporation into DNA. The time required before enough indoleacetic acid (2.8 μm) to enhance thymidine incorporation moves into a segment has been found to be about 35 minutes. The initiation response time for segment tissue that already contains 2.8 μm indoleacetic acid should be no more than about 25 minutes. The rate of labeled thymidine incorporation into DNA is affected by physiological treatments of segments. Moving segments from the light into the dark or defoliating segments or inverting defoliated segments decreases the rate of thymidine incorporation. For segments given all three treatments, indoleacetic acid restores the rate of thymidine incorporation as compared to controls. Darkness, or defoliation or inversion of segments, therefore, may decrease thymidine incorporation into DNA by effecting reduced auxin levels in stem segments. PMID:16659268

  5. Effect of surface and membrane potentials on IAA (indoleactic acid) uptake and binding by zucchini membrane vesicles

    SciTech Connect

    Clark, K.A.; Goldsmith, M.H.M.

    1986-08-01

    The polar transport of the endogenous hormone controlling extension growth of plant cells, indoleacetic acid (IAA), is thought to depend on transmembrane pH and electrical gradients resulting in part from the action of proton ATPases in the plasma membrane. Elements of this transport process are permeation of the membrane by the undissociated lipophilic indoleacetic acid (IAAH) from the acidic apoplast, followed by dissociation of the weak acid and accumulation of the IAA anion (IAA/sup -/) in the alkaline cytoplasm; a saturable symport of IAA/sup -/ with one or more protons; a carrier-mediated efflux of IAA/sup -/ down a considerable electrochemical gradient. The efflux is greater from the basal than the apical end of cells and is thought to be responsible for the overall polarity of the process. This step is also the site of action of napthylphthalamic acid (NPA) and herbicides that inhibit polar transport but stimulate net accumulation of auxin by tissues and cells. We are using membrane vesicles as a simplified system for studying the mechanisms involved in the transport and accumulation of auxin. In particular, we are interested in determining the involvement of the transmembrane pH (pH/sub o/ < pH/sub i/) and voltage gradients (K/sup +/ diffusion potential, (K/sup +/)/sub in/ > (K/sup +/)/sub out/) in IAA uptake. 19 refs., 6 figs.

  6. The Tomato Aux/IAA Transcription Factor IAA9 Is Involved in Fruit Development and Leaf MorphogenesisW⃞

    PubMed Central

    Wang, Hua; Jones, Brian; Li, Zhengguo; Frasse, Pierre; Delalande, Corinne; Regad, Farid; Chaabouni, Salma; Latché, Alain; Pech, Jean-Claude; Bouzayen, Mondher

    2005-01-01

    Auxin/indole-3-acetic acid (Aux/IAA) proteins are transcriptional regulators that mediate many aspects of plant responses to auxin. While functions of most Aux/IAAs have been defined mainly by gain-of-function mutant alleles in Arabidopsis thaliana, phenotypes associated with loss-of-function mutations have been scarce and subtle. We report here that the downregulation of IAA9, a tomato (Solanum lycopersicum) gene from a distinct subfamily of Aux/IAA genes, results in a pleiotropic phenotype, consistent with its ubiquitous expression pattern. IAA9-inhibited lines have simple leaves instead of wild-type compound leaves, and fruit development is triggered before fertilization, giving rise to parthenocarpy. This indicates that IAA9 is a key mediator of leaf morphogenesis and fruit set. In addition, antisense plants displayed auxin-related growth alterations, including enhanced hypocotyl/stem elongation, increased leaf vascularization, and reduced apical dominance. Auxin dose–response assays revealed that IAA9 downregulated lines were hypersensitive to auxin, although the only early auxin-responsive gene that was found to be upregulated in the antisense lines was IAA3. The activity of the IAA3 promoter was stimulated in the IAA9 antisense genetic background, indicating that IAA9 acts in planta as a transcriptional repressor of auxin signaling. While no mutation in any member of subfamily IV has been reported to date, the phenotypes associated with the downregulation of IAA9 reveal distinct and novel roles for members of the Aux/IAA gene family. PMID:16126837

  7. Cloning and expression analysis of novel Aux/IAA family genes in Gossypium hirsutum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Members of the auxin/indole-3-acetic acid (Aux/IAA) gene family encode proteins to mediate the responses of auxin gene expression and to regulate various aspects of plant morphological development. In this paper, we report the identification of nine cDNAs that contain complete open reading frame (OR...

  8. Solanum lycopersicum IAA15 functions in the 2,4-dichlorophenoxyacetic acid herbicide mechanism of action by mediating abscisic acid signalling.

    PubMed

    Xu, Tao; Wang, Yanling; Liu, Xin; Gao, Song; Qi, Mingfang; Li, Tianlai

    2015-07-01

    2,4-Dichlorophenoxyacetic acid (2,4-D), an important plant growth regulator, is the herbicide most commonly used worldwide to control weeds. However, broad-leaf fruits and vegetables are extremely sensitive to herbicides, which can cause damage and result in lost crops when applied in a manner inconsistent with the directions. Despite detailed knowledge of the mechanism of 2,4-D, the regulation of auxin signalling is still unclear. For example, although the major mediators of auxin signalling, including auxin/indole acetic acid (AUX/IAA) proteins and auxin response factors (ARFs), are known to mediate auxinic herbicides, the underlying mechanisms are still unclear. In this study, the effects of 2,4-D on AUX/IAA gene expression in tomato were investigated, and the two most notably up-regulated genes, SlIAA15 and SlIAA29, were selected for further study. Western blotting revealed the substantial accumulation of both SlIAA15 and SlIAA29, and the expression levels of the corresponding genes were increased following abscisic acid (ABA) and ethylene treatment. Overexpressing SlIAA15, but not SlIAA29, induced a 2,4-D herbicide damage phenotype. The 35S::SlIAA15 line exhibited a strong reduction in leaf stomatal density and altered expression of some R2R3 MYB genes that are putatively involved in the regulation of stomatal differentiation. Further study revealed that root elongation in 35S::SlIAA15 was sensitive to ABA treatment, and was most probably due to the altered expression of an ABA signal transduction gene. In addition, the altered auxin sensitivities of SlIAA15 transformants were also explored. These results suggested that SlIAA15 plays an important role in determining the effects of the herbicide 2,4-D. PMID:25948703

  9. A simple method for simultaneous RP-HPLC determination of indolic compounds related to bacterial biosynthesis of indole-3-acetic acid.

    PubMed

    Szkop, Michał; Bielawski, Wiesław

    2013-03-01

    In this short technical report, we present a fast and simple procedure for sample preparation and a single-run Reversed Phase High Performance Liquid Chromatography (RP-HPLC) determination of seven indoles (indole-3-acetic acid, indole-3-acetamide, indole-3-acetonitrile, indole-3-ethanol, indole-3-lactic acid, tryptamine and tryptophan) in bacterial culture supernatants. The separation of the analytes, after a single centrifugal filtration clean-up step, was performed using a gradient elution on a symmetry C8 column followed by fluorimetric detection (λ(ex) = 280/λ(em) = 350 nm). The calibration curves were linear for all of the studied compounds over the concentration range of 0.0625-125 μg mL(-1) (r ( 2 ) ≥ 0.998) and the limits of detection were below 0.015 μg mL(-1). The applicability of the method was confirmed by analysis of Pseudomonas putida culture supernatants. PMID:23111785

  10. Expression of Auxin Response Genes SlIAA1 and SlIAA9 in Solanum lycopersicum During Interaction with Acinetobacter guillouiae SW5.

    PubMed

    Kwon, Hyeok-Do; Song, Hong-Gyu

    2015-06-01

    Indole-3-acetic acid (IAA) production is a typical mechanism of plant growth promotion by some rhizobacteria. However, a functional genomic study is necessary to unravel the function and mechanism of IAA signaling during rhizobacteria-plant interactions. In this study, the expression of SlIAA1 and SlIAA9 among the auxin response genes in tomato was examined during the interaction between IAA-producing Acinetobacter guillouiae SW5 and tomato plants. When 3-day grown tomato seedlings were treated for 30 min with 10~100 µM of IAA produced by bacteria from tryptophan, the relative mRNA levels of SlIAA1 and SlIAA9 increased significantly compared with those of the control, demonstrating that IAA produced by this bacterium can induce the expressions of both genes. Inoculation of live A. guillouiae SW5 to tomato seedlings also increased the expressions of SlIAA1 and SlIAA9, with more mRNA produced at higher bacterial density. In contrast, treatment of tomato seedlings with dead A. guillouiae SW5 did not significantly affect the expression of SlIAA1and SlIAA9. When 3-day bacterial culture in tomato root exudates was administered to tomato seedlings, the relative mRNA level of SlIAA1 increased. This result indicated that the plant may take up IAA produced by bacteria in plant root exudates, which may increase the expression of the auxin response genes, with resulting promotion of plant growth. PMID:25588558

  11. Effect of gibberellic acid (GA), indole acetic acid (IAA) and benzylaminopurine (BAP) on the synthesis of essential oils and the isomerization of methyl chavicol and trans-anethole in Ocimum gratissimum L.

    PubMed

    Hazzoumi, Zakaria; Moustakime, Youssef; Amrani Joutei, Khalid

    2014-01-01

    Basil (O. gratissimum L) is a aromatic and medicinal plant widely used in traditional medicine in Morocco. The aim of this work was to study the effect of three plant growth regulators gibberellic acid (GA), indole 3-acetic acid (IAA) and benzylaminopurine (BAP) on the content and composition of essential oils of this plant, especially on the main compound (methyl chavicol) and its isomer (the trans-anethole). The results showed a wide variation on yield, content and range of the molecule constituent of oil, with a balance of appearances and/or disappearances of a few molecules. GA caused a slight decrease in the oil yield (0.2%), but it increased the diversity of compounds (17 molecules) with the appearance of four new compounds (naphthalene, camphor, germacrene-D, and ledene) and disappearance of (β cedrene, azulene). This variation also caused a very important decrease in the main compound (methyl chavicol) and increases its isomer (trans-anethole). IAA and BAP caused an increase in the yield of essential oil (0.30% and 0.32% respectively) without much influence on the main compounds, but with some change in the composition such as the appearance of (germacrene-D) and the disappearance of (aristolene). PMID:25045609

  12. Involvement of Peroxidase and Indole-3-acetic Acid Oxidase Isozymes from Pear, Tomato, and Blueberry Fruit in Ripening

    PubMed Central

    Frenkel, Chaim

    1972-01-01

    Protein extracts were obtained from climacteric fruits (pear, tomato) and nonclimacteric fruits (blueberry) during various stages of ripening. The use of a gel electrophoresis technique revealed a consistent reinforcement in indoleacetic acid oxidase but not in peroxidase isozymes during ripening. The significance of the results is discussed in relation to the resistance of fruits to ripening and ethylene action. Images PMID:16658043

  13. Phosphate solubilizing and indole-3-acetic acid producing bacteria from the soil of Garhwal Himalaya aimed to improve the growth of rice.

    PubMed

    Gusain, Yogendra Singh; Kamal, Ranveer; Mehta, C M; Singh, U S; Sharma, A K

    2015-01-01

    In the present study, soil bacteria from rainfed agriculture field of Garhwal Himalaya, just prior to sowing of summer crop, were isolated and initially tested for solubilization of inorganic phosphate, production of indole acetic acid (IAA) and siderophore. Two bacterial isolates, having efficient P- solubilizing activity in solid medium, were identified using 16S rRNA sequence analysis as Pseudomonas koreensis strainYB1 Arthrobacter nitroguajacolicus strainYB3 and three bacterial isolates, producing high amount of IAA in liquid medium, were identified as Klebsiella oxytoca strainYB2 and two strain of Arthrobacter nitroguajacolicus, strainYB4 and YB5, respectively. In culture medium supplemented with L-Tryptophan, Klebsiella oxytoca produced high amount of IAA (337.44 μg l(-1)). The selected five bacterial strains were further tested for tricalcium phosphate (TCP) solubilizing abilities at three different incubation temperature viz., 4 degrees C, 10 degrees C and 28 degrees C, under in vitro conditions. At 28 degrees C, three bacterial strains Pseudomonas koreensis, Arthrobacter nitroguajacolicus strainYB4 and Klebsiella oxytoca solubilized the phosphate efficiently. At 10 degrees C only two strains, Pseudomonas koreensis and Arthrobacter nitroguajacolicus strainYB4 solubilized phosphate efficiently as compared to other strains. These five bacterial strains were tested for nitrogen, catalase activity, starch and cellulose hydrolysis as well as growth promotion activity on rice, under controlled conditions. All the five bacterial strains efficiently increased the biomass and phosphorus uptake in Swama and Swarna sub1 varieties of rice. PMID:26536808

  14. Genome-wide analysis of Aux/IAA and ARF gene families in Populus trichocarpa

    SciTech Connect

    Kalluri, Udaya C; DiFazio, Stephen P; Brunner, A.; Tuskan, Gerald A

    2007-01-01

    Auxin/Indole-3-Acetic Acid (Aux/IAA) and Auxin Response Factor (ARF) transcription factors are key regulators of auxin responses in plants. A total of 35 Aux/IAA and 39 ARF genes were identified in the Populus genome. Comparative phylogenetic analysis revealed that the subgroups PoptrARF2, 6, 9 and 16 and PoptrIAA3, 16, 27 and 29 have differentially expanded in Populus relative to Arabidopsis. Activator ARFs were found to be two fold-overrepresented in the Populus genome. PoptrIAA and PoptrARF gene families appear to have expanded due to high segmental and low tandem duplication events. Furthermore, expression studies showed that genes in the expanded PoptrIAA3 subgroup display differential expression. The gene-family analysis reported here will be useful in conducting future functional genomics studies to understand how the molecular roles of these large gene families translate into a diversity of biologically meaningful auxin effects.

  15. Accumulation of intra-cellular polyphosphate in Chlorella vulgaris cells is related to indole-3-acetic acid produced by Azospirillum brasilense.

    PubMed

    Meza, Beatriz; de-Bashan, Luz E; Hernandez, Juan-Pablo; Bashan, Yoav

    2015-06-01

    Accumulation of intra-cellular phosphate, as polyphosphate, was measured when the microalga Chlorella vulgaris was immobilized in alginate with either of two wild-type strains of the microalgae growth-promoting bacterium Azospirillum brasilense or their corresponding IAA-attenuated mutants. Wild type strains of A. brasilense induced higher amounts of intra-cellular phosphate in Chlorella than their respective mutants. Calculations comparing intra-cellular phosphate accumulation by culture or net accumulation by the cell and the amount of IAA that was produced by each of these strains revealed that higher IAA was linked to higher accumulations of intra-cellular phosphate. Application of four levels of exogenous IAA reported for A. brasilense and their IAA-attenuated mutants to cultures of C. vulgaris enhanced accumulation of intra-cellular phosphate; the higher the content of IAA per culture or per single cell, the higher was the amount of accumulated phosphate. When an IAA-attenuated mutant was complemented with exogenous IAA, accumulation of intra-cellular phosphate at the culture level was even higher than phosphate accumulation with the respective wild type strains. When calculating the net accumulation of intra-cellular phosphate in the complementation experiment, net intra-cellular phosphate induced by the IAA-attenuated mutant was completely restored and was similar to the wild strains. We propose that IAA produced by A. brasilense is linked to polyphosphate accumulation in C. vulgaris. PMID:25797155

  16. AXR2 Encodes a Member of the Aux/IAA Protein Family1

    PubMed Central

    Nagpal, Punita; Walker, Loni M.; Young, Jeff C.; Sonawala, Ami; Timpte, Candace; Estelle, Mark; Reed, Jason W.

    2000-01-01

    The dominant gain-of-function axr2-1 mutation of Arabidopsis causes agravitropic root and shoot growth, a short hypocotyl and stem, and auxin-resistant root growth. We have cloned the AXR2 gene using a map-based approach, and find that it is the same as IAA7, a member of the IAA (indole-3-acetic acid) family of auxin-inducible genes. The axr2-1 mutation changes a single amino acid in conserved domain II of AXR2/IAA7. We isolated loss-of-function mutations in AXR2/IAA7 as intragenic suppressors of axr2-1 or in a screen for insertion mutations in IAA genes. A null mutant has a slightly longer hypocotyl than wild-type plants, indicating that AXR2/IAA7 controls development in light-grown seedlings, perhaps in concert with other gene products. Dark-grown axr2-1 mutant plants have short hypocotyls and make leaves, suggesting that activation of AXR2/IAA7 is sufficient to induce morphological responses normally elicited by light. Previously described semidominant mutations in two other Arabidopsis IAA genes cause some of the same phenotypes as axr2-1, but also cause distinct phenotypes. These results illustrate functional differences among members of the Arabidopsis IAA gene family. PMID:10859186

  17. Both Free Indole-3-Acetic Acid and Photosynthetic Performance are Important Players in the Response of Medicago truncatula to Urea and Ammonium Nutrition Under Axenic Conditions.

    PubMed

    Esteban, Raquel; Royo, Beatriz; Urarte, Estibaliz; Zamarreño, Ángel M; Garcia-Mina, José M; Moran, Jose F

    2016-01-01

    We aimed to identify the early stress response and plant performance of Medicago truncatula growing in axenic medium with ammonium or urea as the sole source of nitrogen, with respect to nitrate-based nutrition. Biomass measurements, auxin content analyses, root system architecture (RSA) response analyses, and physiological parameters were determined. Both ammonium and ureic nutrition severely affected the RSA, resulting in changes in the main elongation rate, lateral root development, and insert position from the root base. The auxin content decreased in both urea- and ammonium-treated roots; however, only the ammonium-treated plants were affected at the shoot level. The analysis of chlorophyll a fluorescence transients showed that ammonium affected photosystem II, but urea did not impair photosynthetic activity. Superoxide dismutase isoenzymes in the plastids were moderately affected by urea and ammonium in the roots. Overall, our results showed that low N doses from different sources had no remarkable effects on M. truncatula, with the exception of the differential phenotypic root response. High doses of both ammonium and urea caused great changes in plant length, auxin contents and physiological measurements. Interesting correlations were found between the shoot auxin pool and both plant length and the "performance index" parameter, which is obtained from measurements of the kinetics of chlorophyll a fluorescence. Taken together, these data demonstrate that both the indole-3-acetic acid pool and performance index are important components of the response of M. truncatula under ammonium or urea as the sole N source. PMID:26909089

  18. Both Free Indole-3-Acetic Acid and Photosynthetic Performance are Important Players in the Response of Medicago truncatula to Urea and Ammonium Nutrition Under Axenic Conditions

    PubMed Central

    Esteban, Raquel; Royo, Beatriz; Urarte, Estibaliz; Zamarreño, Ángel M.; Garcia-Mina, José M.; Moran, Jose F.

    2016-01-01

    We aimed to identify the early stress response and plant performance of Medicago truncatula growing in axenic medium with ammonium or urea as the sole source of nitrogen, with respect to nitrate-based nutrition. Biomass measurements, auxin content analyses, root system architecture (RSA) response analyses, and physiological parameters were determined. Both ammonium and ureic nutrition severely affected the RSA, resulting in changes in the main elongation rate, lateral root development, and insert position from the root base. The auxin content decreased in both urea- and ammonium-treated roots; however, only the ammonium-treated plants were affected at the shoot level. The analysis of chlorophyll a fluorescence transients showed that ammonium affected photosystem II, but urea did not impair photosynthetic activity. Superoxide dismutase isoenzymes in the plastids were moderately affected by urea and ammonium in the roots. Overall, our results showed that low N doses from different sources had no remarkable effects on M. truncatula, with the exception of the differential phenotypic root response. High doses of both ammonium and urea caused great changes in plant length, auxin contents and physiological measurements. Interesting correlations were found between the shoot auxin pool and both plant length and the “performance index” parameter, which is obtained from measurements of the kinetics of chlorophyll a fluorescence. Taken together, these data demonstrate that both the indole-3-acetic acid pool and performance index are important components of the response of M. truncatula under ammonium or urea as the sole N source. PMID:26909089

  19. Recognition of the folded conformation of plant hormone (auxin, IAA) conjugates with glutamic and aspartic acids and their amides

    NASA Astrophysics Data System (ADS)

    Antolić, S.; Kveder, M.; Klaić, B.; Magnus, V.; Kojić-Prodić, B.

    2001-01-01

    The molecular structure of the endogenous plant hormone (auxin) conjugate, N-(indol-3-ylacetyl)- L-glutamic acid, is deduced by comparison with N2-(indol-3-ylacetyl)glutamine (IAA-Gln), N2-(indol-3-ylacetyl)asparagine (IAA-Asn) and N-(indol-3-ylacetyl)- L-aspartic acid using X-ray structure analysis, 1H-NMR spectroscopy (NOE measurements) and molecular modelling. The significance of the overall molecular shape, and of the resulting amphiphilic properties, of the compounds studied are discussed in terms of possible implications for trafficking between cell compartments. Both in the solid state and in solution, the molecules are in the hair-pin (folded) conformation in which the side chain is folded over the indole ring. While extended conformations can be detected by molecular dynamics simulations, they are so short-lived that any major influence on the biological properties of the compounds studied is unlikely.

  20. Cleavage of INDOLE-3-ACETIC ACID INDUCIBLE28 mRNA by MicroRNA847 Upregulates Auxin Signaling to Modulate Cell Proliferation and Lateral Organ Growth in Arabidopsis

    PubMed Central

    Wang, Jing-Jing; Guo, Hui-Shan

    2015-01-01

    MicroRNAs function in a range of developmental processes. Here, we demonstrate that miR847 targets the mRNA of the auxin/indole acetic acid (Aux/IAA) repressor-encoding gene IAA28 for cleavage. The rapidly increased accumulation of miR847 in Arabidopsis thaliana coincided with reduced IAA28 mRNA levels upon auxin treatment. This induction of miR847 by auxin was abolished in auxin receptor tir1-1 and auxin-resistant axr1-3 mutants. Further analysis demonstrates that miR847 functions as a positive regulator of auxin-mediated lateral organ development by cleaving IAA28 mRNA. Importantly, the ectopic expression of miR847 increases the expression of cell cycle genes as well as the neoplastic activity of leaf cells, prolonging later-stage rosette leaf growth and producing leaves with serrated margins. Moreover, both miR847 and IAA28 mRNAs are specifically expressed in marginal meristems of rosette leaves and lateral root initiation sites. Our data indicate that auxin-dependent induction of miR847 positively regulates meristematic competence by clearing IAA28 mRNA to upregulate auxin signaling, thereby determining the duration of cell proliferation and lateral organ growth in Arabidopsis. IAA28 mRNA encodes an Aux/IAA repressor protein, which is degraded through the proteasome in response to auxin. Altered signal sensitization to IAA28 mRNA levels, together with targeted IAA28 degradation, ensures a robust signal derepression. PMID:25794935

  1. Cleavage of INDOLE-3-ACETIC ACID INDUCIBLE28 mRNA by microRNA847 upregulates auxin signaling to modulate cell proliferation and lateral organ growth in Arabidopsis.

    PubMed

    Wang, Jing-Jing; Guo, Hui-Shan

    2015-03-01

    MicroRNAs function in a range of developmental processes. Here, we demonstrate that miR847 targets the mRNA of the auxin/indole acetic acid (Aux/IAA) repressor-encoding gene IAA28 for cleavage. The rapidly increased accumulation of miR847 in Arabidopsis thaliana coincided with reduced IAA28 mRNA levels upon auxin treatment. This induction of miR847 by auxin was abolished in auxin receptor tir1-1 and auxin-resistant axr1-3 mutants. Further analysis demonstrates that miR847 functions as a positive regulator of auxin-mediated lateral organ development by cleaving IAA28 mRNA. Importantly, the ectopic expression of miR847 increases the expression of cell cycle genes as well as the neoplastic activity of leaf cells, prolonging later-stage rosette leaf growth and producing leaves with serrated margins. Moreover, both miR847 and IAA28 mRNAs are specifically expressed in marginal meristems of rosette leaves and lateral root initiation sites. Our data indicate that auxin-dependent induction of miR847 positively regulates meristematic competence by clearing IAA28 mRNA to upregulate auxin signaling, thereby determining the duration of cell proliferation and lateral organ growth in Arabidopsis. IAA28 mRNA encodes an Aux/IAA repressor protein, which is degraded through the proteasome in response to auxin. Altered signal sensitization to IAA28 mRNA levels, together with targeted IAA28 degradation, ensures a robust signal derepression. PMID:25794935

  2. Cambial-Region-Specific Expression of the Agrobacterium iaa Genes in Transgenic Aspen Visualized by a Linked uidA Reporter Gene1

    PubMed Central

    Tuominen, Hannele; Puech, Laurence; Regan, Sharon; Fink, Siegfried; Olsson, Olof; Sundberg, Björn

    2000-01-01

    The level of indole-3-acetic acid (IAA) was locally modified in cambial tissues of transgenic aspen (Populus tremula L. × Populus tremuloides Michx.). We also demonstrate the use of a linked reporter gene to visualize the expression of the iaa genes. The rate-limiting bacterial IAA-biosynthetic gene iaaM and the reporter gene for β-glucuronidase (GUS), uidA, were each fused to the cambial-region-specific Agrobacterium rhizogenes rolC promoter and linked on the same T-DNA. In situ hybridization of the iaaM gene confirmed that histochemical analysis of GUS activity could be used to predict iaaM gene expression. Moreover, quantitative fluorometric analysis of GUS activity allowed estimation of the level of de novo production of IAA in transgenic lines carrying a single-copy insert of the iaaM, uidA T-DNA. Microscale analysis of the IAA concentration across the cambial region tissues showed an increase in IAA concentration of about 35% to 40% in the two transgenic lines, but no changes in the radial distribution pattern of IAA compared with wild-type plants. This increase did not result in any changes in the developmental pattern of cambial derivatives or the cambial growth rate, which emphasizes the importance of the radial distribution pattern of IAA in controlling the development of secondary xylem, and suggests that a moderate increase in IAA concentration does not necessarily stimulate growth. PMID:10859183

  3. Genome-wide survey of Aux/IAA gene family members in potato (Solanum tuberosum): Identification, expression analysis, and evaluation of their roles in tuber development.

    PubMed

    Gao, Junpeng; Cao, Xiaoli; Shi, Shandang; Ma, Yuling; Wang, Kai; Liu, Shengjie; Chen, Dan; Chen, Qin; Ma, Haoli

    2016-03-01

    The Auxin/indole-3-acetic acid (Aux/IAA) genes encode short-lived nuclear proteins that are known to be involved in the primary cellular responses to auxin. To date, systematic analysis of the Aux/IAA genes in potato (Solanum tuberosum) has not been conducted. In this study, a total of 26 potato Aux/IAA genes were identified (designated from StIAA1 to StIAA26), and the distribution of four conserved domains shared by the StIAAs were analyzed based on multiple sequence alignment and a motif-based sequence analysis. A phylogenetic analysis of the Aux/IAA gene families of potato and Arabidopsis was also conducted. In order to assess the roles of StIAA genes in tuber development, the results of RNA-seq studies were reformatted to analyze the expression patterns of StIAA genes, and then verified by quantitative real-time PCR. A large number of StIAA genes (12 genes) were highly expressed in stolon organs and in during the tuber initiation and expansion developmental stages, and most of these genes were responsive to indoleacetic acid treatment. Our results suggested that StIAA genes were involved in the process of tuber development and provided insights into functional roles of potato Aux/IAA genes. PMID:26869512

  4. Genome-Wide Analysis and Characterization of Aux/IAA Family Genes in Brassica rapa.

    PubMed

    Paul, Parameswari; Dhandapani, Vignesh; Rameneni, Jana Jeevan; Li, Xiaonan; Sivanandhan, Ganesan; Choi, Su Ryun; Pang, Wenxing; Im, Subin; Lim, Yong Pyo

    2016-01-01

    Auxins are the key players in plant growth development involving leaf formation, phototropism, root, fruit and embryo development. Auxin/Indole-3-Acetic Acid (Aux/IAA) are early auxin response genes noted as transcriptional repressors in plant auxin signaling. However, many studies focus on Aux/ARF gene families and much less is known about the Aux/IAA gene family in Brassica rapa (B. rapa). Here we performed a comprehensive genome-wide analysis and identified 55 Aux/IAA genes in B. rapa using four conserved motifs of Aux/IAA family (PF02309). Chromosomal mapping of the B. rapa Aux/IAA (BrIAA) genes facilitated understanding cluster rearrangement of the crucifer building blocks in the genome. Phylogenetic analysis of BrIAA with Arabidopsis thaliana, Oryza sativa and Zea mays identified 51 sister pairs including 15 same species (BrIAA-BrIAA) and 36 cross species (BrIAA-AtIAA) IAA genes. Among the 55 BrIAA genes, expression of 43 and 45 genes were verified using Genebank B. rapa ESTs and in home developed microarray data from mature leaves of Chiifu and RcBr lines. Despite their huge morphological difference, tissue specific expression analysis of BrIAA genes between the parental lines Chiifu and RcBr showed that the genes followed a similar pattern of expression during leaf development and a different pattern during bud, flower and siliqua development stages. The response of the BrIAA genes to abiotic and auxin stress at different time intervals revealed their involvement in stress response. Single Nucleotide Polymorphisms between IAA genes of reference genome Chiifu and RcBr were focused and identified. Our study examines the scope of conservation and divergence of Aux/IAA genes and their structures in B. rapa. Analyzing the expression and structural variation between two parental lines will significantly contribute to functional genomics of Brassica crops and we belive our study would provide a foundation in understanding the Aux/IAA genes in B. rapa. PMID

  5. Indole-3-acetic acid producing root-associated bacteria on growth of Brazil Pine (Araucaria angustifolia) and Slash Pine (Pinus elliottii).

    PubMed

    Gumiere, Thiago; Ribeiro, Carlos Marcelo; Vasconcellos, Rafael Leandro Figueiredo; Cardoso, Elke Jurandy Bran Nogueira

    2014-04-01

    Araucaria forests in Brazil today correspond to only 0.7 % of the original 200 km(2) of natural forest that covered a great part of the southern and southeastern area of the Atlantic Forest and, although Araucaria angustifolia is an endangered species, illegal exploitation is still going on. As an alternative to the use of hardwoods, Pinus elliottii presents rapid growth and high tolerance to climatic stress and low soil fertility or degraded areas. Thus, the objective of this study was to evaluate the effect of IAA-producing bacteria on the development of A. angustifolia and P. elliottii. We used five bacterial strains previously isolated from the rhizosphere of A. angustifolia, which produce quantities of IAA ranging from 3 to 126 μg mL(-1). Microbiolized seeds were sown in a new gnotobiotic system developed for this work, that allowed the quantification of the plant hormone IAA produced by bacteria, and the evaluation of its effect on seedling development. Also, it was shown that P. elliottii roots were almost as satisfactory as hosts for these IAA producers as A. angustifolia, while different magnitudes of mass increases were found for each species. Thus, we suggest that these microbial groups can be helpful for the development and reestablishment of already degraded forests and that PGPR isolated from Araucaria rhizosphere have the potential to be beneficial in seedling production of P. elliottii. Another finding is that our newly developed gnotobiotic system is highly satisfactory for the evaluation of this effect. PMID:24481491

  6. Constitutive Expression of OsIAA9 Affects Starch Granules Accumulation and Root Gravitropic Response in Arabidopsis

    PubMed Central

    Luo, Sha; Li, Qianqian; Liu, Shanda; Pinas, Nicholaas M.; Tian, Hainan; Wang, Shucai

    2015-01-01

    Auxin/Indole-3-Acetic Acid (Aux/IAA) genes are early auxin response genes ecoding short-lived transcriptional repressors, which regulate auxin signaling in plants by interplay with Auxin Response Factors (ARFs). Most of the Aux/IAA proteins contain four different domains, namely Domain I, Domain II, Domain III, and Domain IV. So far all Aux/IAA mutants with auxin-related phenotypes identified in both Arabidopsis and rice (Oryza sativa) are dominant gain-of-function mutants with mutations in Domain II of the corresponding Aux/IAA proteins, suggest that Aux/IAA proteins in both Arabidopsis and rice are largely functional redundantly, and they may have conserved functions. We report here the functional characterization of a rice Aux/IAA gene, OsIAA9. RT-PCR results showed that expression of OsIAA9 was induced by exogenously applied auxin, suggesting that OsIAA9 is an auxin response gene. Bioinformatic analysis showed that OsIAA9 has a repressor motif in Domain I, a degron in Domain II, and the conserved amino acid signatures for protein-protein interactions in Domain III and Domain IV. By generating transgenic plants expressing GFP-OsIAA9 and examining florescence in the transgenic plants, we found that OsIAA9 is localized in the nucleus. When transfected into protoplasts isolated from rosette leaves of Arabidopsis, OsIAA9 repressed reporter gene expression, and the repression was partially released by exogenously IAA. These results suggest that OsIAA9 is a canonical Aux/IAA protein. Protoplast transfection assays showed that OsIAA9 interacted ARF5, but not ARF6, 7, 8 and 19. Transgenic Arabidopsis plants expressing OsIAA9 have increased number of lateral roots, and reduced gravitropic response. Further analysis showed that OsIAA9 transgenic Arabidopsis plants accumulated fewer granules in their root tips and the distribution of granules was also affected. Taken together, our study showed that OsIAA9 is a transcriptional repressor, and it regulates gravitropic

  7. Protein-protein interaction and gene co-expression maps of ARFs and Aux/IAAs in Arabidopsis

    PubMed Central

    Piya, Sarbottam; Shrestha, Sandesh K.; Binder, Brad; Stewart, C. Neal; Hewezi, Tarek

    2014-01-01

    The phytohormone auxin regulates nearly all aspects of plant growth and development. Based on the current model in Arabidopsis thaliana, Auxin/indole-3-acetic acid (Aux/IAA) proteins repress auxin-inducible genes by inhibiting auxin response transcription factors (ARFs). Experimental evidence suggests that heterodimerization between Aux/IAA and ARF proteins are related to their unique biological functions. The objective of this study was to generate the Aux/IAA-ARF protein-protein interaction map using full length sequences and locate the interacting protein pairs to specific gene co-expression networks in order to define tissue-specific responses of the Aux/IAA-ARF interactome. Pairwise interactions between 19 ARFs and 29 Aux/IAAs resulted in the identification of 213 specific interactions of which 79 interactions were previously unknown. The incorporation of co-expression profiles with protein-protein interaction data revealed a strong correlation of gene co-expression for 70% of the ARF-Aux/IAA interacting pairs in at least one tissue/organ, indicative of the biological significance of these interactions. Importantly, ARF4-8 and 19, which were found to interact with almost all Aux-Aux/IAA showed broad co-expression relationships with Aux/IAA genes, thus, formed the central hubs of the co-expression network. Our analyses provide new insights into the biological significance of ARF-Aux/IAA associations in the morphogenesis and development of various plant tissues and organs. PMID:25566309

  8. Genome-Wide Analysis and Characterization of Aux/IAA Family Genes in Brassica rapa

    PubMed Central

    Rameneni, Jana Jeevan; Li, Xiaonan; Sivanandhan, Ganesan; Choi, Su Ryun; Pang, Wenxing; Im, Subin; Lim, Yong Pyo

    2016-01-01

    Auxins are the key players in plant growth development involving leaf formation, phototropism, root, fruit and embryo development. Auxin/Indole-3-Acetic Acid (Aux/IAA) are early auxin response genes noted as transcriptional repressors in plant auxin signaling. However, many studies focus on Aux/ARF gene families and much less is known about the Aux/IAA gene family in Brassica rapa (B. rapa). Here we performed a comprehensive genome-wide analysis and identified 55 Aux/IAA genes in B. rapa using four conserved motifs of Aux/IAA family (PF02309). Chromosomal mapping of the B. rapa Aux/IAA (BrIAA) genes facilitated understanding cluster rearrangement of the crucifer building blocks in the genome. Phylogenetic analysis of BrIAA with Arabidopsis thaliana, Oryza sativa and Zea mays identified 51 sister pairs including 15 same species (BrIAA—BrIAA) and 36 cross species (BrIAA—AtIAA) IAA genes. Among the 55 BrIAA genes, expression of 43 and 45 genes were verified using Genebank B. rapa ESTs and in home developed microarray data from mature leaves of Chiifu and RcBr lines. Despite their huge morphological difference, tissue specific expression analysis of BrIAA genes between the parental lines Chiifu and RcBr showed that the genes followed a similar pattern of expression during leaf development and a different pattern during bud, flower and siliqua development stages. The response of the BrIAA genes to abiotic and auxin stress at different time intervals revealed their involvement in stress response. Single Nucleotide Polymorphisms between IAA genes of reference genome Chiifu and RcBr were focused and identified. Our study examines the scope of conservation and divergence of Aux/IAA genes and their structures in B. rapa. Analyzing the expression and structural variation between two parental lines will significantly contribute to functional genomics of Brassica crops and we belive our study would provide a foundation in understanding the Aux/IAA genes in B. rapa. PMID

  9. Exogenous IAA treatment enhances phytoremediation of soil contaminated with phenanthrene by promoting soil enzyme activity and increasing microbial biomass.

    PubMed

    Li, Weiming; Wang, Dongsheng; Hu, Feng; Li, Huixin; Ma, Lili; Xu, Li

    2016-06-01

    In this study, we aimed to confirm that indole-3-acetic acid promotes plant uptake of phenanthrene (PHE), stimulates the activity of soil enzymes or microflora, and thereby accelerates the dissipation of PHE in soil. Four treatments were evaluated: PHE-contaminated soil planted with (1) ryegrass (T0), (2) ryegrass and supplemented with 1 mg kg(-1) indole-3-acetic acid (IAA) (T1), (3) ryegrass and supplemented with 5 mg kg(-1) IAA (T5), and (4) ryegrass and supplemented with 10 mg kg(-1) IAA (T10). After 30 days, PHE concentrations were lower for all treatments and the removal rate was 70.19, 89.17, 91.26, and 97.07 % for T0, T1, T5, and T10, respectively. PHE was only detected in the roots and not in the shoots. IAA facilitated the accumulation of PHE in the roots, and plants subjected to the T10 treatment had the highest levels. Exogenous IAA stimulated soil peroxidase activity in a dose-dependent manner, whereas soil polyphenoloxidase activity was not significantly increased, except in T10. Soil microbial biomass also increased in response to IAA treatment, particularly in T10. Furthermore, phospholipid fatty acid analysis showed that IAA treatment increased microbial biomass and alleviated environmental stress. Gram-positive bacteria are largely responsible for polycyclic aromatic hydrocarbon degradation, and we found that the ratio of gram-positive to gram-negative bacteria in the soil significantly increased as the IAA concentrations increased (P < 0.05). Correlation analysis indicated that the increase in soil microbial biomass, enzyme activity, and plant uptake of PHE promotes removal of PHE from the soil. PMID:26884240

  10. How phytohormone IAA and chelator EDTA affect lead uptake by Zn/Cd hyperaccumulator Picris divaricata.

    PubMed

    Du, Rui-Jun; He, Er-Kai; Tang, Ye-Tao; Hu, Peng-Jie; Ying, Rong-Rong; Morel, Jean-Louis; Qiu, Rong-Liang

    2011-01-01

    In this paper, the effects of indole-3-acetic acid (IAA) and/or ethylenediaminetetraacetic acid (EDTA) on lead uptake by a Zn/Cd hyperaccumulator Picris divaricata were studied. P. divaricata responded to Pb by better root system and increased biomass in presence of phytohormone IAA, which was able to reduce the inhibiting effects of Pb on transpiration without reducing the uptake of Pb The application of 100 microM IAA increased plant transpiration rate by about 20% and Pb concentration in leaves by about 37.3% as compared to treatment exposed to Pb alone. The enhanced phytoextraction efficiency could be attributed to the mechanisms played by IAA through alleviating Pb toxicity, creating better root system and plant biomass, promoting a higher transpiration rate as well as regulating the level of nutrient elements. On the contrary, inefficiency of phytoextraction was found with EDTA or the combination of IAA and EDTA probably because most Pb was in the form of Pb-EDTA complex which blocked the uptake by P. divaricata. The present study demonstrated that IAA was able to enhance the phytoextraction of Pb by Zn/Cd hyperaccumulator P. divaricata, providing a feasible method for the phytoremediation of polymetallic contaminated soils. PMID:21972569

  11. Solution structure of the PsIAA4 oligomerization domain reveals interaction modes for transcription factors in early auxin response.

    PubMed

    Dinesh, Dhurvas Chandrasekaran; Kovermann, Michael; Gopalswamy, Mohanraj; Hellmuth, Antje; Calderón Villalobos, Luz Irina A; Lilie, Hauke; Balbach, Jochen; Abel, Steffen

    2015-05-12

    The plant hormone auxin activates primary response genes by facilitating proteolytic removal of auxin/indole-3-acetic acid (AUX/IAA)-inducible repressors, which directly bind to transcriptional auxin response factors (ARF). Most AUX/IAA and ARF proteins share highly conserved C-termini mediating homotypic and heterotypic interactions within and between both protein families. The high-resolution NMR structure of C-terminal domains III and IV of the AUX/IAA protein PsIAA4 from pea (Pisum sativum) revealed a globular ubiquitin-like β-grasp fold with homologies to the Phox and Bem1p (PB1) domain. The PB1 domain of wild-type PsIAA4 features two distinct surface patches of oppositely charged amino acid residues, mediating front-to-back multimerization via electrostatic interactions. Mutations of conserved basic or acidic residues on either face suppressed PsIAA4 PB1 homo-oligomerization in vitro and confirmed directional interaction of full-length PsIAA4 in vivo (yeast two-hybrid system). Mixing of oppositely mutated PsIAA4 PB1 monomers enabled NMR mapping of the negatively charged interface of the reconstituted PsIAA4 PB1 homodimer variant, whose stoichiometry (1:1) and equilibrium binding constant (KD ∼ 6.4 μM) were determined by isothermal titration calorimetry. In silico protein-protein docking studies based on NMR and yeast interaction data derived a model of the PsIAA4 PB1 homodimer, which is comparable with other PB1 domain dimers, but indicated considerable differences between the homodimeric interfaces of AUX/IAA and ARF PB1 domains. Our study provides an impetus for elucidating the molecular determinants that confer specificity to complex protein-protein interaction circuits between members of the two central families of transcription factors important to the regulation of auxin-responsive gene expression. PMID:25918389

  12. Dynamics of the concentration of IAA and some of its conjugates during the induction of somatic embryogenesis in Coffea canephora.

    PubMed

    Ayil-Gutiérrez, Benajmín; Galaz-Ávalos, Rosa; Peña-Cabrera, Eduardo; Loyola-Vargas, Victor

    2013-11-01

    Most of the somatic embryogenesis (SE) process requires the presence, either before or during the embryogenic process, of at least one exogenous auxin. This exogenous auxin induces the presence of endogenous auxins, which appears to be essential for SE induction. We found that during the preincubation period of SE in Coffea canephora, there is an important increase in both free and conjugated indole-3-acetic acid (IAA), as well as indole-3-butyric acid. This increase is accompanied by an increase in the expression of YUCCA (CcYUC), TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (CcTAA1), and GRETCHEN HAGEN 3 (GH3) genes. On the other hand, most of the IAA compounds decreased during the induction of SE. The results presented in this research suggest that a balance between free IAA and its amide conjugates is necessary to allow the expression of SE-related genes. PMID:24299659

  13. Dynamics of the concentration of IAA and some of its conjugates during the induction of somatic embryogenesis in Coffea canephora

    PubMed Central

    Ayil-Gutiérrez, Benajmín; Galaz-Ávalos, Rosa María; Peña-Cabrera, Eduardo; Loyola-Vargas, Victor Manuel

    2013-01-01

    Most of the somatic embryogenesis (SE) process requires the presence, either before or during the embryogenic process, of at least one exogenous auxin. This exogenous auxin induces the presence of endogenous auxins, which appears to be essential for SE induction. We found that during the preincubation period of SE in Coffea canephora, there is an important increase in both free and conjugated indole-3-acetic acid (IAA), as well as indole-3-butyric acid. This increase is accompanied by an increase in the expression of YUCCA (CcYUC), TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (CcTAA1), and GRETCHEN HAGEN 3 (GH3) genes. On the other hand, most of the IAA compounds decreased during the induction of SE. The results presented in this research suggest that a balance between free IAA and its amide conjugates is necessary to allow the expression of SE-related genes. PMID:24299659

  14. Studies on the longitudinal and lateral transport of IAA in the shoots of etiolated corn seedlings

    NASA Technical Reports Server (NTRS)

    Epel, B. L.; Warmbrodt, R. P.; Bandurski, R. S.

    1992-01-01

    The auxin, indole-3-acetic acid, and the symplastic probe, carboxyfluorescein diacetate, were applied to the cut mesocotyl base or coleoptile apex of etiolated Zea mays seedlings and their transport measured and tissue distribution determined. The longitudinal transport of indole-3-acetate was strongly basipolar, while that of carboxyfluorescein was essentially apolar. The longitudinal transport of IAA, like carboxyfluorescein, was mainly in the stele. IAA exhibited a much higher lateral mobility from stele to cortex than did carboxyfluorescein. Based on the calculation of moles probe/kg fw, IAA is 4 times more concentrated in the stele than in the cortex while CF is 24 times higher in concentration in the stele than in the cortex. The structure of the node and the mesocotyl regions just below the node, regions of maximum growth, were examined and plasmodesmatal structure and frequency in these regions determined. The plasmodesmatal frequency, about 3 per micrometer2, between all cell types of the mesocotyl was found to be about 5-8 fold higher than that found for the root. Hypotheses of lateral auxin transport are discussed.

  15. IAA Correlator Center

    NASA Technical Reports Server (NTRS)

    Surkis, Igor; Ken, Voitsekh; Melnikov, Alexey; Mishin, Vladimir; Sokolova, Nadezda; Shantyr, Violet; Zimovsky, Vladimir

    2013-01-01

    The activities of the six-station IAA RAS correlator include regular processing of national geodetic VLBI programs Ru-E, Ru-U, and Ru-F. The Ru-U sessions have been transferred in e-VLBI mode and correlated in the IAA Correlator Center automatically since 2011. The DiFX software correlator is used at the IAA in some astrophysical experiments.

  16. Genome-wide survey and comprehensive expression profiling of Aux/IAA gene family in chickpea and soybean

    PubMed Central

    Singh, Vikash K.; Jain, Mukesh

    2015-01-01

    Auxin plays a central role in many aspects of plant growth and development. Auxin/Indole-3-Acetic Acid (Aux/IAA) genes cooperate with several other components in the perception and signaling of plant hormone auxin. An investigation of chickpea and soybean genomes revealed 22 and 63 putative Aux/IAA genes, respectively. These genes were classified into six subfamilies on the basis of phylogenetic analysis. Among 63 soybean Aux/IAA genes, 57 (90.5%) were found to be duplicated via whole genome duplication (WGD)/segmental events. Transposed duplication played a significant role in tandem arrangements between the members of different subfamilies. Analysis of Ka/Ks ratio of duplicated Aux/IAA genes revealed purifying selection pressure with restricted functional divergence. Promoter sequence analysis revealed several cis-regulatory elements related to auxin, abscisic acid, desiccation, salt, seed, and endosperm, indicating their role in development and stress responses. Expression analysis of chickpea and soybean Aux/IAA genes in various tissues and stages of development demonstrated tissue/stage specific differential expression. In soybean, at least 16 paralog pairs, duplicated via WGD/segmental events, showed almost indistinguishable expression pattern, but eight pairs exhibited significantly diverse expression patterns. Under abiotic stress conditions, such as desiccation, salinity and/or cold, many Aux/IAA genes of chickpea and soybean revealed differential expression. qRT-PCR analysis confirmed the differential expression patterns of selected Aux/IAA genes in chickpea. The analyses presented here provide insights on putative roles of chickpea and soybean Aux/IAA genes and will facilitate elucidation of their precise functions during development and abiotic stress responses. PMID:26579165

  17. Rice Dwarf Virus P2 Protein Hijacks Auxin Signaling by Directly Targeting the Rice OsIAA10 Protein, Enhancing Viral Infection and Disease Development.

    PubMed

    Jin, Lian; Qin, Qingqing; Wang, Yu; Pu, Yingying; Liu, Lifang; Wen, Xing; Ji, Shaoyi; Wu, Jianguo; Wei, Chunhong; Ding, Biao; Li, Yi

    2016-09-01

    The phytohormone auxin plays critical roles in regulating myriads of plant growth and developmental processes. Microbe infection can disturb auxin signaling resulting in defects in these processes, but the underlying mechanisms are poorly understood. Auxin signaling begins with perception of auxin by a transient co-receptor complex consisting of an F-box transport inhibitor response 1/auxin signaling F-box (TIR1/AFB) protein and an auxin/indole-3-acetic acid (Aux/IAA) protein. Auxin binding to the co-receptor triggers ubiquitination and 26S proteasome degradation of the Aux/IAA proteins, leading to subsequent events, including expression of auxin-responsive genes. Here we report that Rice dwarf virus (RDV), a devastating pathogen of rice, causes disease symptoms including dwarfing, increased tiller number and short crown roots in infected rice as a result of reduced sensitivity to auxin signaling. The RDV capsid protein P2 binds OsIAA10, blocking the interaction between OsIAA10 and OsTIR1 and inhibiting 26S proteasome-mediated OsIAA10 degradation. Transgenic rice plants overexpressing wild-type or a dominant-negative (degradation-resistant) mutant of OsIAA10 phenocopy RDV symptoms are more susceptible to RDV infection; however, knockdown of OsIAA10 enhances the resistance of rice to RDV infection. Our findings reveal a previously unknown mechanism of viral protein reprogramming of a key step in auxin signaling initiation that enhances viral infection and pathogenesis. PMID:27606959

  18. Participation of IAA in transduction of gravistimulus in apical cells of moss protonema

    NASA Astrophysics Data System (ADS)

    Oksyniuk, U. A.; Khorkavtsiv, O. Y.; Lesniak, Y. I.

    Growth movements of vascular plant axis organs -- photo-, gravi- and other tropisms -- are tightly connected with IAA transport (Hertel, 1983; Medvedev, 1996; Kiss, 2000). Moss protonema synthesizes IAA (indole-3-acetic acid) and transports it basipetally favouring growth and differentiation of caulonema (Bopp, 1979; Rose, Bopp, 1983; Rose et al., 1983). We aimed at studying the role of IAA in moss protonema gravitropism using exogenous IAA, 1-NAA (1-naphthaleneacetic acid), 2,4D (2,4-dichlorophenoxyacetic acid) and inhibitors of polar IAA transport -- phytotropins NPA (N-1-naphthylphthalamic acid) and TIBA (2,3,5-triiodobenzoic acid). Six-day gravitropic protonema of Ceratodon purpureus and Pohlia nutans were taken for experiments. Auxin and phytotropins solutions were laid on protonema mats the latters being kept in solutions for 30 min. Then the surplus of solutions were poured off and Petri dishes were placed vertically for 6 h. 20 μ M of IAA and of other synthetic auxins did not significantly influence the angle of protonema gravity bending, 40 μ M of the agents, howewer, reduced the per cent of apical cells bendings and their angles. The most expressed influence on the angles of bending had the inhibitors of polar IAA transport -- NPA. 0,1 -- 3,0 μ M of this phytotropin did not change the form of apical cell, did not disturb the general distribution of amyloplasts and did not significantly lower the per cent and the value of gravity bending angle, though 10 μ M of the phytotropin - inhibited gravity bending. The mixture of 1-NAA and NPA having been added into the medium the influence of NPA was lowered and gravitropic growth renewed in course of time. 10 μ M of other phytopropin TIBA also inhibited gravitropism of Ceratodon purpureus and Pohlia nutans protonema. The analysis of basipetal transport of IAA in moss rhizoids and protonema may indicate the availability of special IAA transport in these structures (Bopp, Cerier, 1988). On the basis of the

  19. Effect of IAA on in vitro growth and colonization of Nostoc in plant roots

    PubMed Central

    Hussain, Anwar; Shah, Syed T.; Rahman, Hazir; Irshad, Muhammad; Iqbal, Amjad

    2015-01-01

    Nostoc is widely known for its ability to fix atmospheric nitrogen and the establishment of symbiotic relationship with a wide range of plants from various taxonomic groups. Several strains of Nostoc produce phytohormones that promote growth of its plant partners. Nostoc OS-1 was therefore selected for study because of the presence of putative ipdC gene that encodes a key enzyme to produce Indole-3-acetic acid (IAA). The results indicated that both cellular and released IAA was found high with increasing incubation time and reached to a peak value (i.e., 21 pmol mg-1ch-a) on the third week as determined by UPLC-ESI-MS/MS. Also the Nostoc OS-1 strain efficiently colonized the roots and promoted the growth of rice as well as wheat under axenic conditions and induced ipdC gene that suggested the possible involvement of IAA in these phenotypes. To confirm the impact of IAA on root colonization efficiency and plant promoting phenotypes of Nostoc OS-1, an ipdC knockout mutant was generated by homologous recombinant method. The amount of releasing IAA, in vitro growth, root colonization, and plant promoting efficiency of the ipdC knockout mutant was observed significantly lower than wild type strain under axenic conditions. Importantly, these phenotypes were restored to wild-type levels when the ipdC knockout mutant was complemented with wild type ipdC gene. These results together suggested that ipdC and/or synthesized IAA of Nostoc OS-1 is required for its efficient root colonization and plant promoting activity. PMID:25699072

  20. Assessing the effects of heavy metals in ACC deaminase and IAA production on plant growth-promoting bacteria.

    PubMed

    Carlos, Mendoza-Hernández José; Stefani, Perea-Vélez Yazmin; Janette, Arriola-Morales; Melani, Martínez-Simón Sara; Gabriela, Pérez-Osorio

    2016-01-01

    This study poses a methodology in order to simultaneously quantify ACC deaminase and IAA levels in the same culture medium. Ten bacterial strains isolated from plant rhizosphere naturally settled in mining residues were chosen. These bacterial strains were characterized as PGPB, and all of them showed at least three characteristics (indole-3 acetic acid and siderophore production, ACC deaminase enzyme activity, and inorganic phosphate solubilization). Taxonomic identification showed that the strains belong to Enterobacter, Serratia, Klebsiella, and Escherichia genera. Similarly, both the ACC deaminase enzyme activity and the IAA synthesis in the presence of Cu, As, Pb, Ni, Cd, and Mn were measured. The results showed that both the ACC deaminase enzyme activity and the IAA synthesis were higher with the Pb, As, and Cu treatments than with the Escherichia N16, Enterobacter K131, Enterobacter N9, and Serratia K120 control treatments. On the other hand, Ni, Cd, and Mn negatively affected both the ACC deaminase enzyme activity and the IAA production on every bacterium except on the Klebsiella Mc173 strain. Serratia K120 bacterium got a positive correlation between ACC deaminase and IAA in the presence of every heavy metal, and it also promoted Helianthus annuus plant growth, showing a potential use in phytoremediation systems. PMID:27296962

  1. IAA-producing rhizobacteria from chickpea (Cicer arietinum L.) induce changes in root architecture and increase root biomass.

    PubMed

    Fierro-Coronado, Rosario Alicia; Quiroz-Figueroa, Francisco Roberto; García-Pérez, Luz María; Ramírez-Chávez, Enrique; Molina-Torres, Jorge; Maldonado-Mendoza, Ignacio Eduardo

    2014-10-01

    Rhizobacteria promote and have beneficial effects on plant growth, making them useful to agriculture. Nevertheless, the rhizosphere of the chickpea plant has not been extensively examined. The aim of the present study was to select indole-3-acetic acid (IAA) producing rhizobacteria from the rhizosphere of chickpea plants for their potential use as biofertilizers. After obtaining a collection of 864 bacterial isolates, we performed a screen using the Salkowski reaction for the presence of auxin compounds (such as IAA) in bacterial Luria-Bertani supernatant (BLBS). Our results demonstrate that the Salkowski reaction has a greater specificity for detecting IAA than other tested auxins. Ten bacterial isolates displaying a wide range of auxin accumulation were selected, producing IAA levels of 5 to 90 μmol/L (according to the Salkowski reaction). Bacterial isolates were identified on the basis of 16S rDNA partial sequences: 9 isolates belonged to Enterobacter, and 1 isolate was classified as Serratia. The effect of BLBS on root morphology was evaluated in Arabidopsis thaliana. IAA production by rhizobacteria was confirmed by means of a DR5::GFP construct that is responsive to IAA, and also by HPLC-GC/MS. Finally, we observed that IAA secreted by rhizobacteria (i) modified the root architecture of A. thaliana, (ii) caused an increase in chickpea root biomass, and (iii) activated the green fluorescent protein (GFP) reporter gene driven by the DR5 promoter. These findings provide evidence that these novel bacterial isolates may be considered as putative plant-growth-promoting rhizobacteria modifying root architecture and increasing root biomass. PMID:25231840

  2. Influence of zygomycete-derived D'orenone on IAA signalling in Tricholoma-spruce ectomycorrhiza.

    PubMed

    Wagner, Katharina; Krause, Katrin; David, Anja; Kai, Marco; Jung, Elke-Martina; Sammer, Dominik; Kniemeyer, Olaf; Boland, Wilhelm; Kothe, Erika

    2016-09-01

    Despite the rising interest in microbial communication, only few studies relate to mycorrhization and the pool of potential morphogenic substances produced by the surrounding soil community. Here, we investigated the effect exerted by the C18 - ketone β-apo-13-carotenone, D'orenone, on the ectomycorrhizal basidiomycete Tricholoma vaccinum and its symbiosis with the economically important host tree, spruce (Picea abies). D'orenone is an early intermediate in the biosynthesis of morphogens in sexual development of mucoromycetes, the trisporoids. In the ectomycorrhizal fungus T. vaccinum, D'orenone increased the production and/or release of the phytohormone indole-3-acetic acid (IAA) which had been proposed to be involved in the mutual symbiosis. The induced expression of the fungal aldehyde dehydrogenase, Ald5 is associated with IAA synthesis and excretion. In the host tree, D'orenone modulated root architecture by increasing lateral root length and hypertrophy of root cortex cells, likely via changed IAA concentrations and flux. Thus, we report for the first time on carotenoid metabolites from soil fungi affecting both ectomycorrhizal partners. The data imply a complex network of functions for secondary metabolites which act in an inter-kingdom signalling in soil. PMID:26636983

  3. Acyl substrate preferences of an IAA-amido synthetase account for variations in grape (Vitis vinifera L.) berry ripening caused by different auxinic compounds indicating the importance of auxin conjugation in plant development

    PubMed Central

    Böttcher, Christine; Boss, Paul K.; Davies, Christopher

    2011-01-01

    Nine Gretchen Hagen (GH3) genes were identified in grapevine (Vitis vinifera L.) and six of these were predicted on the basis of protein sequence similarity to act as indole-3-acetic acid (IAA)-amido synthetases. The activity of these enzymes is thought to be important in controlling free IAA levels and one auxin-inducible grapevine GH3 protein, GH3-1, has previously been implicated in the berry ripening process. Ex planta assays showed that the expression of only one other GH3 gene, GH3-2, increased following the treatment of grape berries with auxinic compounds. One of these was the naturally occurring IAA and the other two were synthetic, α-naphthalene acetic acid (NAA) and benzothiazole-2-oxyacetic acid (BTOA). The determination of steady-state kinetic parameters for the recombinant GH3-1 and GH3-2 proteins revealed that both enzymes efficiently conjugated aspartic acid (Asp) to IAA and less well to NAA, while BTOA was a poor substrate. GH3-2 gene expression was induced by IAA treatment of pre-ripening berries with an associated increase in levels of IAA-Asp and a decrease in free IAA levels. This indicates that GH3-2 responded to excess auxin to maintain low levels of free IAA. Grape berry ripening was not affected by IAA application prior to veraison (ripening onset) but was considerably delayed by NAA and even more so by BTOA. The differential effects of the three auxinic compounds on berry ripening can therefore be explained by the induction and acyl substrate specificity of GH3-2. These results further indicate an important role for GH3 proteins in controlling auxin-related plant developmental processes. PMID:21543520

  4. The ipdC, hisC1 and hisC2 genes involved in indole-3-acetic production used as alternative phylogenetic markers in Azospirillum brasilense.

    PubMed

    Jijón-Moreno, Saúl; Marcos-Jiménez, Cynthia; Pedraza, Raúl O; Ramírez-Mata, Alberto; de Salamone, I García; Fernández-Scavino, Ana; Vásquez-Hernández, Claudia A; Soto-Urzúa, Lucia; Baca, Beatriz E

    2015-06-01

    Plant growth-promoting bacteria of the genus Azospirillum are present in the rhizosphere and as endophytes of many crops. In this research we studied 40 Azospirillum strains isolated from different plants and geographic regions. They were first characterized by 16S rDNA restriction analysis, and their phylogenetic position was established by sequencing the genes 16S rDNA, ipdC, hisC1, and hisC2. The latter three genes are involved in the indole-3-pyruvic acid (IPyA) biosynthesis pathway of indole-3-acetic acid (IAA). Furthermore, the suitability of the 16S-23S rDNA intergenic spacer sequence (IGS) for the differentiation of closely related Azospirillum taxa and development of PCR protocols allows for specific detection of strains. The IGS-RFLP analysis enabled intraspecies differentiation, particularly of Azospirillum brasilense and Azospirillum lipoferum strains. Results demonstrated that the ipdC, hisC1, and hisC2 genes are highly conserved in all the assessed A. brasilense isolates, suggesting that these genes can be used as an alternative phylogenetic marker. In addition, IAA production determined by HPLC ranged from 0.17 to 98.2 μg mg(-1) protein. Southern hybridization with the A. brasilense ipdC gene probe did not show, a hybridization signal with A. lipoferum, Azospirillum amazonense, Azospirillum halopreferans and Azospirillum irakense genomic DNA. This suggests that these species produce IAA by other pathways. Because IAA is mainly synthesized via the IPyA pathway in A. brasilense strains, a species that is used worldwide in agriculture, the identification of ipdC, hisC1, and hisC2 genes by PCR may be suitable for selecting exploitable strains. PMID:25842039

  5. A large increase in IAA during development of rice grains correlates with the expression of tryptophan aminotransferase OsTAR1 and a grain-specific YUCCA.

    PubMed

    Abu-Zaitoon, Yousef M; Bennett, Karina; Normanly, Jennifer; Nonhebel, Heather M

    2012-12-01

    The indole-3-acetic acid (IAA) content of developing grains of Oryza sativa subsp. japonica was measured by combined liquid chromatography, tandem mass spectrometry in multiple-reaction-monitoring mode. The increase from 50 ng g(-1) fresh weight to 2.9 µg g(-1) fresh weight from 1 to 14 days after pollination was much larger than that previously reported by enzyme-linked immunoassay methods. The largest increase in IAA content coincided with the start of the major starch deposition phase of grain-fill. The increase in IAA content was strongly correlated with the expression of putative IAA biosynthesis genes, OsYUC9, OsYUC11 and OsTAR1, measured by quantitative reverse transcriptase polymerase chain reaction. These results confirm the importance of the tryptophan aminotransferase/YUCCA pathway in this system. All three genes were expressed in endosperm; expression of OsYUC11 appeared to be confined to endosperm tissue. Phylogenetic analysis indicated that OsYUC11 and AtYUC10 belong to a separate clade of YUCCAs, which do not have orthologues outside the Angiosperms. This clade may have evolved with a specific role in endosperm. Expression of tryptophan decarboxylase in developing rice grains did not correlate with IAA levels, indicating that tryptamine is unlikely to be important for IAA synthesis in this system. In light of these observations, we hypothesize that IAA production in developing rice grains is controlled via expression of OsTAR1, OsYUC9, OsYUC11 and that IAA may be important during starch deposition in addition to its previously suggested role early in grain development. PMID:22582989

  6. [Cloning and expression analysis of differentially expressed genes in Chinese fir stems treated by different concentrations of exogenous IAA].

    PubMed

    Yang, Li-Wei; Shi, Ji-Sen

    2012-04-01

    To reveal the potential genetic mechanisms of indole-3-acetic acid (IAA) that regulate Chinese fir wood formation, cloned the differentially expressed genes via suppress subtractive hybridization (SSH) using the truncated stems treated by 0 and 3 mg IAA/g lanolin as the driver and tester, respectively. A total of 332 unigenes that were involved in cell organization and biosynthesis, developmental processes control, electron transport, stress response, and signal transduction. To further test the results from SSH, we selected those unigenes, whose putative encoding proteins showed significantly homologous with HIRA, PGY1, SMP1, TCT, TRN2, and ARF4, and analyzed their expressed specificity in the wood formative tissues and their response to the secondary developmental changes of vascular cambium stimulated by 0, 1, and 3 mg.IAA/g.lanolin treatment. The results showed that ClHIRA, ClPGY1, and ClARF4, which were specifically expressed in the adaxial zone of stem, were positively response to the activities of cell division and tracheid differentiation stimulated by exogenous IAA treatment. However, ClSMP1, ClTCTP1, and ClTRN2, which were mainly expressed in the abaxial zones of stems, showed negative correlation with the treated levels of exogenous IAA and activities of vascular cambium secondary development at the transcriptional level. This result showed that the differential response of developmental regulatory genes located in different vascular tissues to the level changes of edogenous IAA in stems is likely to be an important molecular mechanism of auxin regulating wood formation. PMID:22522165

  7. Combination of the auxins NAA, IBA, and IAA with GA3 improves the commercial seed-tuber production of potato (Solanum tuberosum L.) under in vitro conditions.

    PubMed

    Kumlay, Ahmet Metin

    2014-01-01

    The study compared the effects of 1.0 × MS medium containing various concentrations of α-naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA), alone or in combination with gibberellic acid (GA3) in micropropagation of three potato (Solanum tuberosum L.) cultivars Pasinler, Granola, and Caspar using binodal stem cuttings. The results testified improved regeneration on 1.0 × MS medium containing variants of NAA, IAA, and IBA plus GA3 on all cultivars. The minimum days to shoot induction on three cultivars ranged 4.25-5 d on 1.0 × MS medium containing 0.25 mg L(-1) GA3 + 1 mg L(-1) NAA. The longest shoots (11.8 cm), maximum number of nodes (13.50), and maximum number of leaves (11.00) were recorded on cv. Caspar on 1.0 × MS medium containing 1 mg L(-1) NAA + 0.25 mg L(-1) GA3. The minimum time to root induction (12.25 d) was noted on cv. Pasinler on the same medium. All of the regenerated shoots could be easily rooted. The results showed that the combined effect of various concentrations of NAA, IAA, and IBA plus GA3 was more pronounced compared to the auxins used alone. The results of this research are of significant importance for potato breeders. PMID:25028654

  8. FTIR spectroscopic study of the phytohormone auxin (Indol-3-ylacetic Acid, IAA) and its n-alkylated and monohalogenated derivatives

    NASA Astrophysics Data System (ADS)

    Lutz, Bert T. G.; van der Windt, Erik; Kanters, Jan; Klämbt, Dieter; Kojić-Prodić, Biserka; Ramek, Michael

    1996-09-01

    In the framework of structure/activity correlation studies the plant growth hormone auxin and its natural analogue 4-Cl-IAA, as well as their synthetic congeners, were studied by FTIR spectroscopy. The analysis was focused on the NH and CO stretching vibrations which can be the most sensitive probes of intra- and intermolecular interactions, particularly to hydrogen bonds. However, it emerged that vC = O vibrations of both monomer and dimer are not affected by substitution. The aliphatic CH 2 group acts as an insulator between the conjugated π-system of indole and the carboxylic group, thus prohibiting a direct effect on the vibration CO. On the contrary, the stretching vibrations NH are influenced by halogenation and hydrogen bonding. The experimental data are in good agreement with the results of quantum chemical ab initio calculations of NH vibrations for IAA and several chlorine substituted IAAs. However, a simple correlation between substitution and spectral properties of indole NH cannot be found. The measurements were performed in the solid state (KBr pellets) and in polar (diethylether) and nonpolar (CDCI 3) solutions. From the measurements in diethylether, it follows that in dilute solution IAA and derivatives are predominantly present as monomer, whereas in CDCl 3 the equilibrium is in favour of the dimer form. In aqueous solution at the concentrations used in growth experiments solvated monomer will be the active component. Bioactivity of auxin and analogues with their NH stretching frequency shifts cannot be correlated in a simple way.

  9. Fruit load induces changes in global gene expression and in abscisic acid (ABA) and indole acetic acid (IAA) homeostasis in citrus buds.

    PubMed

    Shalom, Liron; Samuels, Sivan; Zur, Naftali; Shlizerman, Lyudmila; Doron-Faigenboim, Adi; Blumwald, Eduardo; Sadka, Avi

    2014-07-01

    Many fruit trees undergo cycles of heavy fruit load (ON-Crop) in one year, followed by low fruit load (OFF-Crop) the following year, a phenomenon known as alternate bearing (AB). The mechanism by which fruit load affects flowering induction during the following year (return bloom) is still unclear. Although not proven, it is commonly accepted that the fruit or an organ which senses fruit presence generates an inhibitory signal that moves into the bud and inhibits apical meristem transition. Indeed, fruit removal from ON-Crop trees (de-fruiting) induces return bloom. Identification of regulatory or metabolic processes modified in the bud in association with altered fruit load might shed light on the nature of the AB signalling process. The bud transcriptome of de-fruited citrus trees was compared with those of ON- and OFF-Crop trees. Fruit removal resulted in relatively rapid changes in global gene expression, including induction of photosynthetic genes and proteins. Altered regulatory mechanisms included abscisic acid (ABA) metabolism and auxin polar transport. Genes of ABA biosynthesis were induced; however, hormone analyses showed that the ABA level was reduced in OFF-Crop buds and in buds shortly following fruit removal. Additionally, genes associated with Ca(2+)-dependent auxin polar transport were remarkably induced in buds of OFF-Crop and de-fruited trees. Hormone analyses showed that auxin levels were reduced in these buds as compared with ON-Crop buds. In view of the auxin transport autoinhibition theory, the possibility that auxin distribution plays a role in determining bud fate is discussed. PMID:24706719

  10. Fruit load induces changes in global gene expression and in abscisic acid (ABA) and indole acetic acid (IAA) homeostasis in citrus buds

    PubMed Central

    Shalom, Liron; Samuels, Sivan; Zur, Naftali; Shlizerman, Lyudmila; Doron-Faigenboim, Adi; Blumwald, Eduardo; Sadka, Avi

    2014-01-01

    Many fruit trees undergo cycles of heavy fruit load (ON-Crop) in one year, followed by low fruit load (OFF-Crop) the following year, a phenomenon known as alternate bearing (AB). The mechanism by which fruit load affects flowering induction during the following year (return bloom) is still unclear. Although not proven, it is commonly accepted that the fruit or an organ which senses fruit presence generates an inhibitory signal that moves into the bud and inhibits apical meristem transition. Indeed, fruit removal from ON-Crop trees (de-fruiting) induces return bloom. Identification of regulatory or metabolic processes modified in the bud in association with altered fruit load might shed light on the nature of the AB signalling process. The bud transcriptome of de-fruited citrus trees was compared with those of ON- and OFF-Crop trees. Fruit removal resulted in relatively rapid changes in global gene expression, including induction of photosynthetic genes and proteins. Altered regulatory mechanisms included abscisic acid (ABA) metabolism and auxin polar transport. Genes of ABA biosynthesis were induced; however, hormone analyses showed that the ABA level was reduced in OFF-Crop buds and in buds shortly following fruit removal. Additionally, genes associated with Ca2+-dependent auxin polar transport were remarkably induced in buds of OFF-Crop and de-fruited trees. Hormone analyses showed that auxin levels were reduced in these buds as compared with ON-Crop buds. In view of the auxin transport autoinhibition theory, the possibility that auxin distribution plays a role in determining bud fate is discussed. PMID:24706719

  11. Isolation and characterization of mutants of Arabidopsis thaliana with increased resistance to growth inhibition by indoleacetic acid-amino acid conjugates.

    PubMed Central

    Campanella, J J; Ludwig-Mueller, J; Town, C D

    1996-01-01

    Two mutants of Arabidopsis thaliana that are resistant to growth inhibition by indole-3-acetic acid (IAA)-phenylalanine have been isolated. Both mutants were 2- to 3-fold more resistant than wild type to inhibition by IAA-phenylalanine, IAA-alanine, and IAA-glycine in root growth assays. The mutant icr1 (but not icr2) also shows some resistance to IAA-aspartate. Studies using 3H-labeled IAA-phenylalanine showed that the uptake of conjugate from the medium by icr1 was the same as wild type and was reduced by about 25% in icr2. No differences in hydrolysis of the exogenous conjugate were detected between the mutants and their wild-type parents. There was no significant metabolism of the IAA released from the [3H]IAA-phenylalanine, whereas exogenous [3H]IAA was rapidly metabolized to two unidentified products considerably more polar than IAA. Analysis of a cross between icr1 and icr2 indicated that these mutations were at distinct loci and that their effects were additive, and preliminary mapping data indicated that icr1 and icr2 were located at the top and bottom of chromosome V, respectively. PMID:8883385

  12. Quantitation of Indoleacetic Acid Conjugates in Bean Seeds by Direct Tissue Hydrolysis 1

    PubMed Central

    Bialek, Krystyna; Cohen, Jerry D.

    1989-01-01

    Gas chromatography-selected ion monitoring-mass spectral analysis using [13C6]indole-3-acetic acid (IAA) as an internal standard provides an effective means for quantitation of IAA liberated during direct strong basic hydrolysis of bean (Phaseolus vulgaris L.) seed powder, provided that extra precautions are undertaken to exclude oxygen from the reaction vial. Direct seed powder hydrolysis revealed that the major portion of amide IAA conjugates in bean seeds are not extractable by aqueous acetone, the solvent used commonly for IAA conjugate extraction from seeds and other plant tissues. Strong basic hydrolysis of plant tissue can be used to provide new information on IAA content. Images Figure 1 PMID:16666783

  13. Nitric oxide metabolism and indole acetic acid biosynthesis cross-talk in Azospirillum brasilense SM.

    PubMed

    Koul, Vatsala; Tripathi, Chandrakant; Adholeya, Alok; Kochar, Mandira

    2015-04-01

    Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase (nosZ), nitrous oxide reductase regulator (nosR) and nitric oxide reductase (norB) were identified in the plant-associated bacterium (PAB) Azospirillum brasilense SM. NO presence was confirmed in all overexpressing strains, while improvement in the plant growth response of these strains was mediated by increased NO and indole-3-acetic acid (IAA) levels in the strains. Electron microscopy showed random distribution to biofilm, with surface colonization of pleiomorphic Azospirilla. Quantitative IAA estimation highlighted a crucial role of nosR and norBC in regulating IAA biosynthesis. The NO quencher and donor reduced/blocked IAA biosynthesis by all strains, indicating their common regulatory role in IAA biosynthesis. Tryptophan (Trp) and l-Arginine (Arg) showed higher expression of NO genes tested, while in the case of ipdC, only Trp and IAA increased expression, while Arg had no significant effect. The highest nosR expression in SMnosR in the presence of IAA and Trp, along with its 2-fold IAA level, confirmed the relationship of nosR overexpression with Trp in increasing IAA. These results indicate a strong correlation between IAA and NO in A. brasilense SM and suggest the existence of cross-talk or shared signaling mechanisms in these two growth regulators. PMID:25700632

  14. Identification of IAA-oxidase in peroxidase isozymes from cotton plant leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the functions of plant peroxidase is to regulate the indole acetic acid (IAA) hormonal level by oxidizing it to inactive 3-methyleneoxyindole. IAA-binding proteins and plant peroxidase revealed five structurally similar fragments. We have isolated peroxidase isozymes with IAA-oxidase activit...

  15. Canalization of auxin flow by Aux/IAA-ARF-dependent feedback regulation of PIN polarity.

    PubMed

    Sauer, Michael; Balla, Jozef; Luschnig, Christian; Wisniewska, Justyna; Reinöhl, Vilém; Friml, Jirí; Benková, Eva

    2006-10-15

    Plant development is characterized by a profound ability to regenerate and form tissues with new axes of polarity. An unsolved question concerns how the position within a tissue and cues from neighboring cells are integrated to specify the polarity of individual cells. The canalization hypothesis proposes a feedback effect of the phytohormone auxin on the directionality of intercellular auxin flow as a means to polarize tissues. Here we identify a cellular and molecular mechanism for canalization. Local auxin application, wounding, or auxin accumulation during de novo organ formation lead to rearrangements in the subcellular polar localization of PIN auxin transport components. This auxin effect on PIN polarity is cell-specific, does not depend on PIN transcription, and involves the Aux/IAA-ARF (indole-3-acetic acid-auxin response factor) signaling pathway. Our data suggest that auxin acts as polarizing cue, which links individual cell polarity with tissue and organ polarity through control of PIN polar targeting. This feedback regulation provides a conceptual framework for polarization during multiple regenerative and patterning processes in plants. PMID:17043314

  16. Combination of the Auxins NAA, IBA, and IAA with GA3 Improves the Commercial Seed-Tuber Production of Potato (Solanum tuberosum L.) under In Vitro Conditions

    PubMed Central

    Kumlay, Ahmet Metin

    2014-01-01

    The study compared the effects of 1.0 × MS medium containing various concentrations of α-naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA), alone or in combination with gibberellic acid (GA3) in micropropagation of three potato (Solanum tuberosum L.) cultivars Pasinler, Granola, and Caspar using binodal stem cuttings. The results testified improved regeneration on 1.0 × MS medium containing variants of NAA, IAA, and IBA plus GA3 on all cultivars. The minimum days to shoot induction on three cultivars ranged 4.25–5 d on 1.0 × MS medium containing 0.25 mg L−1  GA3 + 1 mg L−1 NAA. The longest shoots (11.8 cm), maximum number of nodes (13.50), and maximum number of leaves (11.00) were recorded on cv. Caspar on 1.0 × MS medium containing 1 mg L−1  NAA + 0.25 mg L−1 GA3. The minimum time to root induction (12.25 d) was noted on cv. Pasinler on the same medium. All of the regenerated shoots could be easily rooted. The results showed that the combined effect of various concentrations of NAA, IAA, and IBA plus GA3 was more pronounced compared to the auxins used alone. The results of this research are of significant importance for potato breeders. PMID:25028654

  17. PpYUC11, a strong candidate gene for the stony hard phenotype in peach (Prunus persica L. Batsch), participates in IAA biosynthesis during fruit ripening.

    PubMed

    Pan, Lei; Zeng, Wenfang; Niu, Liang; Lu, Zhenhua; Liu, Hui; Cui, Guochao; Zhu, Yunqin; Chu, Jinfang; Li, Weiping; Fang, Weichao; Cai, Zuguo; Li, Guohuai; Wang, Zhiqiang

    2015-12-01

    High concentrations of indole-3-acetic acid (IAA) are required for climacteric ethylene biosynthesis to cause fruit softening in melting flesh peaches at the late ripening stage. By contrast, the fruits of stony hard peach cultivars do not soften and produce little ethylene due to the low IAA concentrations. To investigate the regulation of IAA accumulation during peach ripening [the transition from stage S3 to stage S4 III (climacteric)], a digital gene expression (DGE) analysis was performed. The expression patterns of auxin-homeostasis-related genes were compared in fruits of the melting flesh peach 'Goldhoney 3' and the stony hard flesh peach 'Yumyeong' during the ripening stage. It is revealed here that a YUCCA flavin mono-oxygenase gene (PpYUC11, ppa008176m), a key gene in auxin biosynthesis, displayed an identical differential expression profile to the profiles of IAA accumulation and PpACS1 transcription: the mRNA transcripts increased at the late ripening stage in melting flesh peaches but were below the limit of detection in mature fruits of stony hard peaches. In addition, the strong association between intron TC microsatellite genotypes of PpYUC11 and the flesh texture (normal or stony hard) is described in 43 peach varieties, indicating that this locus may be responsible for the stony hard phenotype in peach. These findings support the hypothesis that PpYUC11 may play an essential role in auxin biosynthesis during peach fruit ripening and is a candidate gene for the control of the stony hard phenotype in peach. PMID:26307136

  18. PpYUC11, a strong candidate gene for the stony hard phenotype in peach (Prunus persica L. Batsch), participates in IAA biosynthesis during fruit ripening

    PubMed Central

    Pan, Lei; Zeng, Wenfang; Niu, Liang; Lu, Zhenhua; Liu, Hui; Cui, Guochao; Zhu, Yunqin; Chu, Jinfang; Li, Weiping; Fang, Weichao; Cai, Zuguo; Li, Guohuai; Wang, Zhiqiang

    2015-01-01

    High concentrations of indole-3-acetic acid (IAA) are required for climacteric ethylene biosynthesis to cause fruit softening in melting flesh peaches at the late ripening stage. By contrast, the fruits of stony hard peach cultivars do not soften and produce little ethylene due to the low IAA concentrations. To investigate the regulation of IAA accumulation during peach ripening [the transition from stage S3 to stage S4 III (climacteric)], a digital gene expression (DGE) analysis was performed. The expression patterns of auxin-homeostasis-related genes were compared in fruits of the melting flesh peach ‘Goldhoney 3’ and the stony hard flesh peach ‘Yumyeong’ during the ripening stage. It is revealed here that a YUCCA flavin mono-oxygenase gene (PpYUC11, ppa008176m), a key gene in auxin biosynthesis, displayed an identical differential expression profile to the profiles of IAA accumulation and PpACS1 transcription: the mRNA transcripts increased at the late ripening stage in melting flesh peaches but were below the limit of detection in mature fruits of stony hard peaches. In addition, the strong association between intron TC microsatellite genotypes of PpYUC11 and the flesh texture (normal or stony hard) is described in 43 peach varieties, indicating that this locus may be responsible for the stony hard phenotype in peach. These findings support the hypothesis that PpYUC11 may play an essential role in auxin biosynthesis during peach fruit ripening and is a candidate gene for the control of the stony hard phenotype in peach. PMID:26307136

  19. IAA-Ala Resistant3, an evolutionarily conserved target of miR167, mediates Arabidopsis root architecture changes during high osmotic stress.

    PubMed

    Kinoshita, Natsuko; Wang, Huan; Kasahara, Hiroyuki; Liu, Jun; Macpherson, Cameron; Machida, Yasunori; Kamiya, Yuji; Hannah, Matthew A; Chua, Nam-Hai

    2012-09-01

    The functions of microRNAs and their target mRNAs in Arabidopsis thaliana development have been widely documented; however, roles of stress-responsive microRNAs and their targets are not as well understood. Using small RNA deep sequencing and ATH1 microarrays to profile mRNAs, we identified IAA-Ala Resistant3 (IAR3) as a new target of miR167a. As expected, IAR3 mRNA was cleaved at the miR167a complementary site and under high osmotic stress miR167a levels decreased, whereas IAR3 mRNA levels increased. IAR3 hydrolyzes an inactive form of auxin (indole-3-acetic acid [IAA]-alanine) and releases bioactive auxin (IAA), a central phytohormone for root development. In contrast with the wild type, iar3 mutants accumulated reduced IAA levels and did not display high osmotic stress-induced root architecture changes. Transgenic plants expressing a cleavage-resistant form of IAR3 mRNA accumulated high levels of IAR3 mRNAs and showed increased lateral root development compared with transgenic plants expressing wild-type IAR3. Expression of an inducible noncoding RNA to sequester miR167a by target mimicry led to an increase in IAR3 mRNA levels, further confirming the inverse relationship between the two partners. Sequence comparison revealed the miR167 target site on IAR3 mRNA is conserved in evolutionarily distant plant species. Finally, we showed that IAR3 is required for drought tolerance. PMID:22960911

  20. The virtual machine (VM) scaler: an infrastructure manager supporting environmental modeling on IaaS clouds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrastructure-as-a-service (IaaS) clouds provide a new medium for deployment of environmental modeling applications. Harnessing advancements in virtualization, IaaS clouds can provide dynamic scalable infrastructure to better support scientific modeling computational demands. Providing scientific m...

  1. Sphere of influence of indole acetic acid and nitric oxide in bacteria.

    PubMed

    Koul, Vatsala; Adholeya, Alok; Kochar, Mandira

    2015-05-01

    Bacterial biosynthesis of the phytohormone, indole-3-acetic acid (IAA) is well established and along with the diffusible gaseous molecule, nitric oxide (NO) is known to positively regulate the developmental processes of plant roots. IAA and NO act as signaling molecules in plant-microbe interactions as they modulate the gene expression in both, plants and microorganisms. Although IAA and NO may not be required for essential bacterial physiological processes, numerous studies point towards a crosstalk between IAA and NO in the rhizosphere. In this review, we describe various IAA and NO-responsive or sensing genes/proteins/regulators. There is also growing evidence for the interaction of IAA and NO with other plant growth regulators and the involvement of NO with the quorum sensing system in biofilm formation and virulence. This interactive network can greatly impact the host plant-microbe interactions in the soil. Coupled with this, the specialized σ(54) -dependent transcription observed in some of the IAA and NO-influenced genes can confer inducibility to these traits in bacteria and may allow the expression of IAA and NO-influenced microbial genes in nutrient limiting or changing environmental conditions for the benefit of plants. PMID:24913042

  2. GA3 and other signal regulators (MeJA and IAA) improve xanthumin biosynthesis in different manners in Xanthium strumarium L.

    PubMed

    Li, Changfu; Chen, Fangfang; Zhang, Yansheng

    2014-01-01

    Xanthanolides from Xanthium strumarium L. exhibit various pharmacological activities and these compounds are mainly produced in the glandular trichomes of aerial plant parts. The regulation of xanthanolide biosynthesis has never been reported in the literature. In this study, the effects of phytohormonal stimulation on xanthumin (a xanthanolide compound) biosynthesis, glandular trichomes and germacrene A synthase (GAS) gene expression in X. strumarium L. young leaves were investigated. The exogenous applications of methyl jasmonate (MeJA), indole-3-acetic acid (IAA), and gibberrellin A3 (GA3) at appropriate concentrations were all found to improve xanthumin biosynthesis, but in different ways. It was suggested that a higher gland density stimulated by MeJA (400 µM) or IAA (200 µM) treatment caused at least in part an improvement in xanthumin production, whereas GA3 (10 µM) led to an improvement by up-regulating xanthumin biosynthetic genes within gland cells, not by forming more glandular trichomes. Compared to the plants before the flowering stage, plants that had initiated flowering showed enhanced xanthumin biosynthesis, but no higher gland density, an effect was similar to that caused by exogenous GA3 treatment. PMID:25157461

  3. The Systemic Acquired Resistance Regulator OsNPR1 Attenuates Growth by Repressing Auxin Signaling through Promoting IAA-Amido Synthase Expression.

    PubMed

    Li, Xiaozun; Yang, Dong-Lei; Sun, Li; Li, Qun; Mao, Bizeng; He, Zuhua

    2016-09-01

    Systemic acquired resistance is a long-lasting and broad-spectrum disease resistance to pathogens. Our previous study demonstrated that overexpression of NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (OsNPR1), a master gene for systemic acquired resistance in rice (Oryza sativa), greatly enhanced resistance to bacterial blight caused by Xanthomonas oryzae pv oryzae However, the growth and development of the OsNPR1 overexpression (OsNPR1-OX) plants were restrained, and the mechanism remained elusive. In this study, we dissected the OsNPR1-induced growth inhibition. We found that the OsNPR1-OX lines displayed phenotypes mimicking auxin-defective mutants, with decreases in root system, seed number and weight, internode elongation, and tiller number. Whole-genome expression analysis revealed that genes related to the auxin metabolism and signaling pathway were differentially expressed between the OsNPR1-OX and wild-type plants. Consistently, the indole-3-acetic acid (IAA) content was decreased and the auxin distribution pattern was altered in OsNPR1-OX plants. Importantly, we found that some GH3 family members, in particular OsGH3.8 coding IAA-amido synthetase, were constitutively up-regulated in OsNPR1-OX plants. Decreased OsGH3.8 expression by RNA interference could partially restore IAA level and largely rescue the restrained growth and development phenotypes but did not affect the disease resistance of OsNPR1-OX plants. Taken together, we revealed that OsNPR1 affects rice growth and development by disrupting the auxin pathway at least partially through indirectly up-regulating OsGH3.8 expression. PMID:27378815

  4. Dynamic web cache publishing for IaaS clouds using Shoal

    NASA Astrophysics Data System (ADS)

    Gable, Ian; Chester, Michael; Armstrong, Patrick; Berghaus, Frank; Charbonneau, Andre; Leavett-Brown, Colin; Paterson, Michael; Prior, Robert; Sobie, Randall; Taylor, Ryan

    2014-06-01

    We have developed a highly scalable application, called Shoal, for tracking and utilizing a distributed set of HTTP web caches. Our application uses the Squid HTTP cache. Squid servers advertise their existence to the Shoal server via AMQP messaging by running Shoal Agent. The Shoal server provides a simple REST interface that allows clients to determine their closest Squid cache. Our goal is to dynamically instantiate Squid caches on IaaS clouds in response to client demand. Shoal provides the VMs on IaaS clouds with the location of the nearest dynamically instantiated Squid Cache.

  5. Apigenin and quercetin promote. Delta. pH-dependent accumulation of IAA in membrane vesicles

    SciTech Connect

    Woolard, D.D.; Clark, K.A. )

    1990-05-01

    Flavonoids may act as regulators of polar auxin transport. In the presence of a pH gradient (pH 8{sub in}/6{sub out}) the flavonoids quercetin and apigenin, as well as the synthetic herbicide napthylphthalamic acid (NPA), promote the accumulation of IAA in membrane vesicles from dark-grown zucchini hypocotyls. Simultaneous accumulation of {sup 3}H-IAA (10 nM) and {sup 14}C-butyric acid (5 {mu}M; included as a pH probe) was determined by a filtration assay after incubating the vesicles with 3 nM to 100 {mu}M quercetin, apigenin, NPA or unlabeled IAA. Maximal stimulation (% of Control) was observed with 3 {mu}M NPA (130%), 1 {mu}M quercetin (120%), or 3 {mu}M apigenin (115%); {Delta}pH was not affected by these concentrations. As reported by others, IAA uptake was saturable: 1 {mu}M unlabeled IAA eliminated {Delta}pH-dependent uptake of {sup 3}H-IAA without altering {Delta}pH. However, at 30 to 100 {mu}M, every compound tested collapsed the imposed pH gradient and therefore abolished specific {sup 3}H-IAA uptake.

  6. VM Capacity-Aware Scheduling within Budget Constraints in IaaS Clouds

    PubMed Central

    Thanasias, Vasileios; Lee, Choonhwa; Hanif, Muhammad; Kim, Eunsam; Helal, Sumi

    2016-01-01

    Recently, cloud computing has drawn significant attention from both industry and academia, bringing unprecedented changes to computing and information technology. The infrastructure-as-a-Service (IaaS) model offers new abilities such as the elastic provisioning and relinquishing of computing resources in response to workload fluctuations. However, because the demand for resources dynamically changes over time, the provisioning of resources in a way that a given budget is efficiently utilized while maintaining a sufficing performance remains a key challenge. This paper addresses the problem of task scheduling and resource provisioning for a set of tasks running on IaaS clouds; it presents novel provisioning and scheduling algorithms capable of executing tasks within a given budget, while minimizing the slowdown due to the budget constraint. Our simulation study demonstrates a substantial reduction up to 70% in the overall task slowdown rate by the proposed algorithms. PMID:27501046

  7. VM Capacity-Aware Scheduling within Budget Constraints in IaaS Clouds.

    PubMed

    Thanasias, Vasileios; Lee, Choonhwa; Hanif, Muhammad; Kim, Eunsam; Helal, Sumi

    2016-01-01

    Recently, cloud computing has drawn significant attention from both industry and academia, bringing unprecedented changes to computing and information technology. The infrastructure-as-a-Service (IaaS) model offers new abilities such as the elastic provisioning and relinquishing of computing resources in response to workload fluctuations. However, because the demand for resources dynamically changes over time, the provisioning of resources in a way that a given budget is efficiently utilized while maintaining a sufficing performance remains a key challenge. This paper addresses the problem of task scheduling and resource provisioning for a set of tasks running on IaaS clouds; it presents novel provisioning and scheduling algorithms capable of executing tasks within a given budget, while minimizing the slowdown due to the budget constraint. Our simulation study demonstrates a substantial reduction up to 70% in the overall task slowdown rate by the proposed algorithms. PMID:27501046

  8. The Aux/IAA, Sl-IAA17 regulates quality parameters over tomato fruit development

    PubMed Central

    Su, LY; Audran, C; Bouzayen, M; Roustan, JP; Chervin, C

    2015-01-01

    Auxin is known to be involved in all the stages of fruit development. Aux/IAAs are regulators of the auxin signaling at the transcription level. In a recent study, using RNAi strategy to limit the expression Sl-IAA17, it was shown that this tomato AuxIAA regulates fruit size mainly through altering the ploidy level of pericarp cells. Indeed, Sl-IAA17 down-regulated lines showed fruit with larger diameter, bigger volume and heavier weight than wild-type. The increase in fruit size was associated with thicker pericarp rather than larger locular spaces. The thicker pericarp was linked to larger cells harboring higher ploidy level, probably due to more active endoreduplication at the beginning of fruit development. The present report describes some additional phenotypes, not described in the initial article, among which are soluble solid content, juice pH, firmness, seed weight and fruit morphology. PMID:26317283

  9. Cinnamic acid increases lignin production and inhibits soybean root growth.

    PubMed

    Salvador, Victor Hugo; Lima, Rogério Barbosa; dos Santos, Wanderley Dantas; Soares, Anderson Ricardo; Böhm, Paulo Alfredo Feitoza; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth. PMID:23922685

  10. Anti-inflammatory effects of alpinone 3-acetate from Alpinia japonica seeds.

    PubMed

    Kakegawa, Tomohito; Miyazaki, Aya; Yasukawa, Ken

    2016-07-01

    We aimed to investigate the bioactive components of Alpinia japonica as anti-inflammatory compounds using searches of the Alpinia genus, and subsequently demonstrated that alpinone 3-acetate markedly inhibits 12-O-tetradecanoyiphorbol 13-acetate-induced inflammation in a mouse model of ear edema. To assess other bioactivities of alpinone 3-acetate, we performed translatome analyses and compared them with those of hydrocortisone. Polysome-associated mRNAs were prepared from alpinone 3-acetate- or hydrocortisone-treated and control cells from 12-O-tetradecanoyiphorbol 13-acetate-induced THP-1-derived macrophages cultured in the presence of Escherichia coli O-111 lipopolysaccharide. Subsequent microarray analysis revealed that alpinone 3-acetate and hydrocortisone upregulated and downregulated the same 155 and 41 genes, respectively. Moreover, direct comparisons of translationally regulated genes indicated 5 and 10 gene probes that were upregulated and downregulated by alpinone 3-acetate and hydrocortisone, respectively. In conclusion, assays of 12-O-tetradecanoyiphorbol 13-acetate-induced inflammation ear edema in mice and polysome profiling of alpinone 3-acetate bioactivities indicated similar medicinal possibilities to those of hydrocortisone. PMID:27137785

  11. IAA RAS Radio Telescope Monitoring System

    NASA Astrophysics Data System (ADS)

    Mikhailov, A.; Lavrov, A.

    2007-07-01

    Institute of Applied Astronomy of the Russian Academy of Sciences (IAA RAS) has three identical radio telescopes, the receiving complex of which consists of five two-channel receivers of different bands, six cryogen systems, and additional devices: four local oscillators, phase calibration generators and IF commutator. The design, hardware and data communication protocol are described. The most convenient way to join the devices of the receiving complex into the common monitoring system is to use the interface which allows to connect numerous devices to the data bus. For the purpose of data communication regulation and to exclude conflicts, a data communication protocol has been designed, which operates with complex formatted data sequences. Formation of such sequences requires considerable data processing capability. That is provided by a microcontroller chip in each slave device. The test version of the software for the central computer has been developed in IAA RAS. We are developing the Mark IV FS software extension modules, which will allow us to control the receiving complex of the radio telescope by special SNAP commands from both operator input and schedule files. We are also developing procedures of automatic measurements of SEFD, system noise temperature and other parameters, available both in VLBI and single-dish modes of operation. The system described has been installed on all IAA RAS radio telescopes at "Svetloe", "Zelenchukskaya" and "Badary" observatories. It has proved to be working quite reliably and to show the perfonmance expected.

  12. Monitoring of IaaS and scientific applications on the Cloud using the Elasticsearch ecosystem

    NASA Astrophysics Data System (ADS)

    Bagnasco, S.; Berzano, D.; Guarise, A.; Lusso, S.; Masera, M.; Vallero, S.

    2015-05-01

    The private Cloud at the Torino INFN computing centre offers IaaS services to different scientific computing applications. The infrastructure is managed with the OpenNebula cloud controller. The main stakeholders of the facility are a grid Tier-2 site for the ALICE collaboration at LHC, an interactive analysis facility for the same experiment and a grid Tier-2 site for the BES-III collaboration, plus an increasing number of other small tenants. Besides keeping track of the usage, the automation of dynamic allocation of resources to tenants requires detailed monitoring and accounting of the resource usage. As a first investigation towards this, we set up a monitoring system to inspect the site activities both in terms of IaaS and applications running on the hosted virtual instances. For this purpose we used the Elasticsearch, Logstash and Kibana stack. In the current implementation, the heterogeneous accounting information is fed to different MySQL databases and sent to Elasticsearch via a custom Logstash plugin. For the IaaS metering, we developed sensors for the OpenNebula API. The IaaS level information gathered through the API is sent to the MySQL database through an ad-hoc developed RESTful web service, which is also used for other accounting purposes. Concerning the application level, we used the Root plugin TProofMonSenderSQL to collect accounting data from the interactive analysis facility. The BES-III virtual instances used to be monitored with Zabbix, as a proof of concept we also retrieve the information contained in the Zabbix database. Each of these three cases is indexed separately in Elasticsearch. We are now starting to consider dismissing the intermediate level provided by the SQL database and evaluating a NoSQL option as a unique central database for all the monitoring information. We setup a set of Kibana dashboards with pre-defined queries in order to monitor the relevant information in each case. In this way we have achieved a uniform monitoring

  13. Partial purification and characterization of an inducible indole-3-acetyl-L-aspartic acid hydrolase from Enterobacter agglomerans

    SciTech Connect

    Chou, Jyh-Ching |; Cohen, J.D.; Mulbry, W.W.

    1996-11-01

    Indole-3-acetyl-amino acid conjugate hydrolases are believed to be important in the regulation of indole-3-acetic acid (IAA) metabolism in plants and therefore have potential uses for the alteration of plant IAA metabolism. To isolate bacterial strains exhibiting significant indole-3-acetyl-aspartate (IAA-Asp) hydrolase activity, a sewage sludge inoculation was cultured under conditions in which IAA-Asp served as the sole source of carbon and nitrogen. One isolate, Enterobacter agglomerans, showed hydrolase activity inducible by IAA-L-Asp or N-acetyl-L-Asp but not by IAA, (NH{sub 4}){sub 2}SO{sub 4}, urea, or indoleacetamide. Among a total of 17 IAA conjugates tested as potential substrates, the enzyme had an exclusively high substrate specificity for IAA-L-Asp of 13.5 mM. The optimal pH for this enzyme was between 8.0 and 8.5. In extraction buffer containing 0.8 mM Mg{sup 2+} the hydrolase activity was inhibited to 80% by 1 mM dithiothreitol and to 60% by 1 mm CuSO{sub 4}; the activity was increased by 40% with 1mM MnSO{sub 4}. However, in extraction buffer with no trace elements, the hydrolase activity was inhibited to 50% by either 1 mM dithiothreitol or 1% Triton X-100 (Sigma). These results suggest that disulfide bonding might be essential for enzyme activity. Purification of the hydrolase by hydroxyapatite and TSK-phenyl (HP-Genenchem, South San Francisco, CA) preparative high-performance liquid chromatography yielded a major 45-kD polypeptide as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 45 refs., 5 figs., 3 tabs.

  14. Gibberellin application at pre-bloom in grapevines down-regulates the expressions of VvIAA9 and VvARF7, negative regulators of fruit set initiation, during parthenocarpic fruit development.

    PubMed

    Jung, Chan Jin; Hur, Youn Young; Yu, Hee-Ju; Noh, Jung-Ho; Park, Kyo-Sun; Lee, Hee Jae

    2014-01-01

    Fruit set is initiated only after fertilization and is tightly regulated primarily by gibberellins (GAs) and auxins. The application of either of these hormones induces parthenocarpy, fruit set without fertilization, but the molecular mechanism underlying this induction is poorly understood. In the present study, we have shown that the parthenocarpic fruits induced by GA application at pre-bloom result from the interaction of GA with auxin signaling. The transcriptional levels of the putative negative regulators of fruit set initiation, including Vitis auxin/indole-3-acetic acid transcription factor 9 (VvIAA9), Vitis auxin response factor 7 (VvARF7), and VvARF8 were monitored during inflorescence development in seeded diploid 'Tamnara' grapevines with or without GA application. Without GA application, VvIAA9, VvARF7, and VvARF8 were expressed at a relatively high level before full bloom, but decreased thereafter following pollination. After GA application at 14 days before full bloom (DBF); however, the expression levels of VvIAA9 and VvARF7 declined at 5 DBF prior to pollination. The effects of GA application on auxin levels or auxin signaling were also analyzed by monitoring the expression patterns of auxin biosynthesis genes and auxin-responsive genes with or without GA application. Transcription levels of the auxin biosynthesis genes Vitis anthranilate synthase β subunit (VvASB1-like), Vitis YUCCA2 (VvYUC2), and VvYUC6 were not significantly changed by GA application. However, the expressions of Vitis Gretchen Hagen3.2 (VvGH3.2) and VvGH3.3, auxin-responsive genes, were up-regulated from 2 DBF to full bloom with GA application. Furthermore, the Vitis GA signaling gene, VvDELLA was up-regulated by GA application during 12 DBF to 7 DBF, prior to down-regulation of VvIAA9 and VvARF7. These results suggest that VvIAA9 and VvARF7 are negative regulators of fruit set initiation in grapevines, and GA signaling is integrated with auxin signaling via VvDELLA during

  15. Gibberellin Application at Pre-Bloom in Grapevines Down-Regulates the Expressions of VvIAA9 and VvARF7, Negative Regulators of Fruit Set Initiation, during Parthenocarpic Fruit Development

    PubMed Central

    Jung, Chan Jin; Hur, Youn Young; Yu, Hee-Ju; Noh, Jung-Ho; Park, Kyo-Sun; Lee, Hee Jae

    2014-01-01

    Fruit set is initiated only after fertilization and is tightly regulated primarily by gibberellins (GAs) and auxins. The application of either of these hormones induces parthenocarpy, fruit set without fertilization, but the molecular mechanism underlying this induction is poorly understood. In the present study, we have shown that the parthenocarpic fruits induced by GA application at pre-bloom result from the interaction of GA with auxin signaling. The transcriptional levels of the putative negative regulators of fruit set initiation, including Vitis auxin/indole-3-acetic acid transcription factor 9 (VvIAA9), Vitis auxin response factor 7 (VvARF7), and VvARF8 were monitored during inflorescence development in seeded diploid ‘Tamnara’ grapevines with or without GA application. Without GA application, VvIAA9, VvARF7, and VvARF8 were expressed at a relatively high level before full bloom, but decreased thereafter following pollination. After GA application at 14 days before full bloom (DBF); however, the expression levels of VvIAA9 and VvARF7 declined at 5 DBF prior to pollination. The effects of GA application on auxin levels or auxin signaling were also analyzed by monitoring the expression patterns of auxin biosynthesis genes and auxin-responsive genes with or without GA application. Transcription levels of the auxin biosynthesis genes Vitis anthranilate synthase β subunit (VvASB1-like), Vitis YUCCA2 (VvYUC2), and VvYUC6 were not significantly changed by GA application. However, the expressions of Vitis Gretchen Hagen3.2 (VvGH3.2) and VvGH3.3, auxin-responsive genes, were up-regulated from 2 DBF to full bloom with GA application. Furthermore, the Vitis GA signaling gene, VvDELLA was up-regulated by GA application during 12 DBF to 7 DBF, prior to down-regulation of VvIAA9 and VvARF7. These results suggest that VvIAA9 and VvARF7 are negative regulators of fruit set initiation in grapevines, and GA signaling is integrated with auxin signaling via VvDELLA during

  16. Increased IAA transport in axillary buds upon release from apical dominance

    SciTech Connect

    Tamas, I.A.; Reimels, A.J. )

    1989-04-01

    To investigate the transport of indoleacetic acid (IAA) simultaneously in the stem and the axillary bud, bud-bearing nodal stem segments of Phaseolus vulgaris L. were excised and agar blocks containing {sup 14}C-IAA or {sup 3}H-IAA were placed on the apical cut surface and the bud stump respectively. A plain receiver block was placed on the basal end. After a period of transport, the stem segment and the attached bud stump were sectioned, and the activity of sections and agar blocks was counted. We found that the transport of {sup 3}H-IAA from the bud stump to the receiver was greatly accelerated in plants decapitated one or two days prior to the experiment, compared to the intact controls. Decapitation also caused a decrease in the ability of the stem axis to transport {sup 14}C-IAA from the apical to the basal end of the stem segment. The increased ability of the axillary bud to transport IAA, relative to that of the stem axis, may play a role int he release of the bud from apical dominance.

  17. The IAA RAS Correlator First Results

    NASA Technical Reports Server (NTRS)

    Surkis, Igor; Melnikov, Alexey; Shantyr, Violet; Zimovsky, Vladimir

    2010-01-01

    In 2009 the national Russian VLBI observations were processed by the new correlator ARC (Astrometric Radiointerferometric Correlator). The ARC is a VSI-H correlator and equipped with Mark 5B playback terminals. During 2009 ARC was used to process a series of VLBI sessions, observed on stations Svetloe, Zelenchukskaya, and Badary. NGS files were formed, and EOP parameters were obtained by IAA RAS Analysis Center. The accuracies of the pole coordinates and UT1-UTC were 1-2 mas and 0.07-0.1 ms, respectively.

  18. NGAP: A (Brief) Update PaaS, IaaS, Onbording, and the Future

    NASA Technical Reports Server (NTRS)

    McLaughlin, Brett; Pawloski, Andrew

    2016-01-01

    NASA ESDIS has charged the EED2 program with delivering a NASA-compliant, secure, cloud-based platform for application hosting. More than just a move to the cloud, this has forced us to examine all aspects of application hosting, from resource management to system administration, patching to monitoring, deployment to multiple environments. The result of this mandate is NGAP, the NASA General Application Platform. In this presentation, we will also discuss the various applications we are supporting and targeting, and their architectures including NGAPs move to support both PaaS and IaaS architectures.

  19. A batch system for HEP applications on a distributed IaaS cloud

    NASA Astrophysics Data System (ADS)

    Gable, I.; Agarwal, A.; Anderson, M.; Armstrong, P.; Fransham, K.; Leavett-Brown, D. Harris C.; Paterson, M.; Penfold-Brown, D.; Sobie, R. J.; Vliet, M.; Charbonneau, A.; Impey, R.; Podaima, W.

    2011-12-01

    The emergence of academic and commercial Infrastructure-as-a-Service (IaaS) clouds is opening access to new resources for the HEP community. In this paper we will describe a system we have developed for creating a single dynamic batch environment spanning multiple IaaS clouds of different types (e.g. Nimbus, OpenNebula, Amazon EC2). A HEP user interacting with the system submits a job description file with a pointer to their VM image. VM images can either be created by users directly or provided to the users. We have created a new software component called Cloud Scheduler that detects waiting jobs and boots the user VM required on any one of the available cloud resources. As the user VMs appear, they are attached to the job queues of a central Condor job scheduler, the job scheduler then submits the jobs to the VMs. The number of VMs available to the user is expanded and contracted dynamically depending on the number of user jobs. We present the motivation and design of the system with particular emphasis on Cloud Scheduler. We show that the system provides the ability to exploit academic and commercial cloud sites in a transparent fashion.

  20. Evolution of ephemerides EPM of IAA RAS

    NASA Astrophysics Data System (ADS)

    Pitjeva, E.

    2015-08-01

    The evolution of numerical EPM ephemerides of the IAA RAS from available EPM2004, EPM2008, EPM2011, to the new EPM2014 version is presented briefly. The comparison progress of ephemerides includes: the growing database of different types of observations from classical optical to radio technical of spacecraft from 1913 to 2014, enlarged up to more 800000 measurements; improved dynamical model from mutual perturbations of all planets, the Sun, the Moon, 301 largest asteroids to additional perturbations from of 30 largest trans-neptunian objects (TNO) and perturbations from remaining smaller asteroids and TNO modeled by the two-dimensional asteroid ring and the one-dimensional TNO ring; program software ERA-7 to ERA-8.

  1. G2LC: Resources Autoscaling for Real Time Bioinformatics Applications in IaaS

    PubMed Central

    Hu, Rongdong; Liu, Guangming; Jiang, Jingfei; Wang, Lixin

    2015-01-01

    Cloud computing has started to change the way how bioinformatics research is being carried out. Researchers who have taken advantage of this technology can process larger amounts of data and speed up scientific discovery. The variability in data volume results in variable computing requirements. Therefore, bioinformatics researchers are pursuing more reliable and efficient methods for conducting sequencing analyses. This paper proposes an automated resource provisioning method, G2LC, for bioinformatics applications in IaaS. It enables application to output the results in a real time manner. Its main purpose is to guarantee applications performance, while improving resource utilization. Real sequence searching data of BLAST is used to evaluate the effectiveness of G2LC. Experimental results show that G2LC guarantees the application performance, while resource is saved up to 20.14%. PMID:26504488

  2. G2LC: Resources Autoscaling for Real Time Bioinformatics Applications in IaaS.

    PubMed

    Hu, Rongdong; Liu, Guangming; Jiang, Jingfei; Wang, Lixin

    2015-01-01

    Cloud computing has started to change the way how bioinformatics research is being carried out. Researchers who have taken advantage of this technology can process larger amounts of data and speed up scientific discovery. The variability in data volume results in variable computing requirements. Therefore, bioinformatics researchers are pursuing more reliable and efficient methods for conducting sequencing analyses. This paper proposes an automated resource provisioning method, G2LC, for bioinformatics applications in IaaS. It enables application to output the results in a real time manner. Its main purpose is to guarantee applications performance, while improving resource utilization. Real sequence searching data of BLAST is used to evaluate the effectiveness of G2LC. Experimental results show that G2LC guarantees the application performance, while resource is saved up to 20.14%. PMID:26504488

  3. Determining Overhead, Variance & Isolation Metrics in Virtualization for IaaS Cloud

    NASA Astrophysics Data System (ADS)

    Ismail, Bukhary Ikhwan; Jagadisan, Devendran; Khalid, Mohammad Fairus

    Infrastructure as a Service cloud provides an open avenue for consumer to easily own computing and storage infrastructure. User can invent new services and have it deploy in a fraction of a time. As services being consumed, user expect consistent performance of their virtual machines. To host an IaaS, virtualization performance and behaviour need to be understood first. In this paper we present virtualization benchmarking methods, results and analysis in various resource utilization scenarios. The scenarios are Performance Overhead; the cost of virtualization compared to physical, Performance Variance; the VM instance performance when more VM is instantiate and Performance Fairness or Isolation; the study of fairness on each of the guest instances under stress environment. These studies provides us the fundamental understanding of virtualization technology.

  4. Tetraethylene glycol promoted two-step, one-pot rapid synthesis of indole-3-[1-11C]acetic acid

    SciTech Connect

    Lee, Sojeong; Qu, Wenchao; Alexoff, David L.; Shea, Colleen; Kim, Dohyun; Schueller, Michael; Fowler, Joanna S.

    2014-12-12

    An operationally friendly, two-step, one-pot process has been developed for the rapid synthesis of carbon-11 labeled indole-3-acetic acid ([11]IAA or [11]auxin). By replacing an aprotic polar solvent with tetraethylene glycol, nucleophilic [11]cyanation and alkaline hydrolysis reactions were performed consecutively in a single pot without a time-consuming intermediate purification step. The entire production time for this updated procedure is 55 min, which dramatically simplifies the entire synthesis and reduces the starting radioactivity required for a whole plant imaging study.

  5. Tetraethylene glycol promoted two-step, one-pot rapid synthesis of indole-3-[1-11C]acetic acid

    DOE PAGESBeta

    Lee, Sojeong; Qu, Wenchao; Alexoff, David L.; Shea, Colleen; Kim, Dohyun; Schueller, Michael; Fowler, Joanna S.

    2014-12-12

    An operationally friendly, two-step, one-pot process has been developed for the rapid synthesis of carbon-11 labeled indole-3-acetic acid ([11]IAA or [11]auxin). By replacing an aprotic polar solvent with tetraethylene glycol, nucleophilic [11]cyanation and alkaline hydrolysis reactions were performed consecutively in a single pot without a time-consuming intermediate purification step. The entire production time for this updated procedure is 55 min, which dramatically simplifies the entire synthesis and reduces the starting radioactivity required for a whole plant imaging study.

  6. The new IAA Light Scattering Facility

    NASA Astrophysics Data System (ADS)

    Muñoz, O.; Moreno, F.; Molina, A.; Guirado, D.; Ramos, J. L.; López, A.; Girela, F.; Costillo, L. P.

    2005-05-01

    We are building up a light scattering setup at the Instituto de Astrofísica de Andalucía (IAA), Granada, Spain. The design of this new setup is based on the well known apparatus currently located at the Astronomical Institute "Anton Pannekoek", University of Amsterdam, The Neteherlands [1],[2]. By using a polarization modulation technique, all scattering matrix elements as function of the scattering angle are obtained from 8 separate measurement runs. In this new setup we use an Argon-Kripton laser (483 nm, 488 nm, 514 nm, 568 nm, and 647 nm) as light source. The detectors are mounted on dove tails that allow their movement backward and forward. In addition, the detectors have been designed to minimize blockage of the laser beam at positions close to the forward and backward directions. In this way we intend to do measurements covering an angle range from 3 to 177 degrees. The alignment of the optics is automatically done and controlled from the computer reducing the measurement time.

  7. myo-Inositol 1,3-acetals as early intermediates during the synthesis of cyclitol derivatives.

    PubMed

    Gurale, Bharat P; Sardessai, Richa S; Shashidhar, Mysore S

    2014-11-18

    Synthetic sequences starting from commercially available myo-inositol necessarily involve protection-deprotection strategies of its six hydroxyl groups. Several strategies have been developed/attempted over the last several decades leading to the synthesis of naturally occurring phosphoinositols, their analogs, and cyclitol derivatives. Of late, myo-inositol 1,3-acetals, which can be obtained by the reductive cleavage of myo-inositol orthoesters have emerged as early intermediates for the synthesis of phosphorylated and other inositol derivatives. This mini-review is an attempt to illustrate the economy and convenience of using myo-inositol 1,3-acetals as early intermediates during syntheses from myo-inositol. PMID:25216930

  8. The rib1 Mutant of Arabidopsis Has Alterations in Indole-3-Butyric Acid Transport, Hypocotyl Elongation, and Root Architecture1

    PubMed Central

    Poupart, Julie; Rashotte, Aaron M.; Muday, Gloria K.; Waddell, Candace S.

    2005-01-01

    Polar transport of the auxin indole-3-butyric acid (IBA) has recently been shown to occur in Arabidopsis (Arabidopis thaliana) seedlings, yet the physiological importance of this process has yet to be fully resolved. Here we describe the first demonstration of altered IBA transport in an Arabidopsis mutant, and show that the resistant to IBA (rib1) mutation results in alterations in growth, development, and response to exogenous auxin consistent with an important physiological role for IBA transport. Both hypocotyl and root IBA basipetal transport are decreased in rib1 and root acropetal IBA transport is increased. While indole-3-acetic acid (IAA) transport levels are not different in rib1 compared to wild type, root acropetal IAA transport is insensitive to the IAA efflux inhibitor naphthylphthalamic acid in rib1, as is the dependent physiological process of lateral root formation. These observed changes in IBA transport are accompanied by altered rib1 phenotypes. Previously, rib1 roots were shown to be less sensitive to growth inhibition by IBA, but to have a wild-type response to IAA in root elongation. rib1 is also less sensitive to IBA in stimulation of lateral root formation and in hypocotyl elongation under most, but not all, light and sucrose conditions. rib1 has wild-type responses to IAA, except under one set of conditions, low light and 1.5% sucrose, in which both hypocotyl elongation and lateral root formation show altered IAA response. Taken together, our results support a model in which endogenous IBA influences wild-type seedling morphology. Modifications in IBA distribution in seedlings affect hypocotyl and root elongation, as well as lateral root formation. PMID:16258013

  9. The Arabidopsis PLEIOTROPIC DRUG RESISTANCE8/ABCG36 ATP Binding Cassette Transporter Modulates Sensitivity to the Auxin Precursor Indole-3-Butyric Acid[C][W

    PubMed Central

    Strader, Lucia C.; Bartel, Bonnie

    2009-01-01

    Plants have developed numerous mechanisms to store hormones in inactive but readily available states, enabling rapid responses to environmental changes. The phytohormone auxin has a number of storage precursors, including indole-3-butyric acid (IBA), which is apparently shortened to active indole-3-acetic acid (IAA) in peroxisomes by a process similar to fatty acid β-oxidation. Whereas metabolism of auxin precursors is beginning to be understood, the biological significance of the various precursors is virtually unknown. We identified an Arabidopsis thaliana mutant that specifically restores IBA, but not IAA, responsiveness to auxin signaling mutants. This mutant is defective in PLEIOTROPIC DRUG RESISTANCE8 (PDR8)/PENETRATION3/ABCG36, a plasma membrane–localized ATP binding cassette transporter that has established roles in pathogen responses and cadmium transport. We found that pdr8 mutants display defects in efflux of the auxin precursor IBA and developmental defects in root hair and cotyledon expansion that reveal previously unknown roles for IBA-derived IAA in plant growth and development. Our results are consistent with the possibility that limiting accumulation of the IAA precursor IBA via PDR8-promoted efflux contributes to auxin homeostasis. PMID:19648296

  10. Light inhibits gravity-regulated peg formation and asymmetric mRNA accumulation of auxin-inducible CsIAA1 in the cortex of the transition zone in cucumber seedlings

    NASA Astrophysics Data System (ADS)

    Fujii, Nobuharu; Saito, Yuko; Miyazawa, Yutaka; Takahashi, Hideyuki

    When cucumber seedlings are grown horizontally, a specialized protuberance, termed the peg, develops on the lower side of the transition zone between the hypocotyl and the root. Gravimorphogenesis regulates the lateral positioning of the peg in the transition zone and it has been suggested that auxin plays an important role in peg formation in cucumber seedlings. Here, we found that light inhibited auxin-regulated peg formation. In the transition zone of horizontally positioned cucumber seedlings grown in the dark, we detected an asymmetric accumulation of mRNA from the auxin-inducible gene CsIAA1 in the epidermis and cortex. However, in seedlings grown under illumination, this asymmetry was greatly reduced. In dark- and light-grown seedlings, application of 10 -3 M indole-3-acetic acid induced peg formation on both the lower and upper sides of the transition zone. These results suggest that light inhibits peg formation via modification of auxin distribution and/or levels in the transition zone of cucumber seedlings.

  11. Oligomerization of SCFTIR1 Is Essential for Aux/IAA Degradation and Auxin Signaling in Arabidopsis.

    PubMed

    Dezfulian, Mohammad H; Jalili, Espanta; Roberto, Don Karl A; Moss, Britney L; Khoo, Kerry; Nemhauser, Jennifer L; Crosby, William L

    2016-09-01

    The phytohormone auxin is a key regulator of plant growth and development. Molecular studies in Arabidopsis have shown that auxin perception and signaling is mediated via TIR1/AFB-Aux/IAA co-receptors that assemble as part of the SCFTIR1/AFB E3 ubiquitin-ligase complex and direct the auxin-regulated degradation of Aux/IAA transcriptional repressors. Despite the importance of auxin signaling, little is known about the functional regulation of the TIR1/AFB receptor family. Here we show that TIR1 can oligomerize in planta via a set of spatially clustered amino acid residues. While none of the residues identified reside in the interaction interface of the TIR1-Aux/IAA degron, they nonetheless regulate the binding of TIR1 to Aux/IAA substrate proteins and their subsequent degradation in vivo as an essential aspect of auxin signaling. We propose oligomerization of TIR1 as a novel regulatory mechanism in the regulation of auxin-mediated plant patterning and development. PMID:27618443

  12. The rib1 Mutant Is Resistant to Indole-3-Butyric Acid, an Endogenous Auxin in Arabidopsis1

    PubMed Central

    Poupart, Julie; Waddell, Candace S.

    2000-01-01

    The presence of indole-3-butyric acid (IBA) as an endogenous auxin in Arabidopsis has been recently demonstrated. However, the in vivo role of IBA remains to be elucidated. We present the characterization of a semi-dominant mutant that is affected in its response to IBA, but shows a wild-type response to indole-3-acetic acid (IAA), the predominant and most studied form of auxin. We have named this mutant rib1 for resistant to IBA. Root elongation assays show that rib1 is specifically resistant to IBA, to the synthetic auxin 2,4-dichlorophenoxyacetic acid, and to auxin transport inhibitors. rib1 does not display increased resistance to IAA, to the synthetic auxin naphthalene acetic acid, or to other classes of plant hormones. rib1 individuals also have other root specific phenotypes including a shortened primary root, an increased number of lateral roots, and a more variable response than wild type to a change in gravitational vector. Adult rib1 plants are morphologically indistinguishable from wild-type plants. These phenotypes suggest that rib1 alters IBA activity in the root, thereby affecting root development and response to environmental stimuli. We propose models in which RIB1 has a function in either IBA transport or response. Our experiments also suggest that IBA does not use the same mechanism to exit cells as does IAA and we propose a model for IBA transport. PMID:11115890

  13. Low irradiances affect abscisic acid, indole-3-acidic acid, and cytokinin levels of wheat (Triticum aestivum L.) tissues

    NASA Technical Reports Server (NTRS)

    Nan, R.; Carman, J. G.; Salisbury, F. B.

    1999-01-01

    Wheat (Triticum aestivum L.) plants were grown under four irradiance levels: 1,400, 400, 200, and 100 micromol m-2 s-1. Leaves and roots were sampled before, during, and after the boot stage, and levels of abscisic acid (ABA), indole-3-acetic acid (IAA), zeatin, zeatin riboside, dihydrozeatin, dihydrozeatin riboside, isopentenyl adenine, and isopentenyl adenosine were quantified using noncompetitive indirect ELISA systems. Levels of IAA in leaves and roots of plants exposed to 100 micromol m-2 s-1 of irradiance were 0.7 and 2.9 micromol kg-1 dry mass (DM), respectively. These levels were 0.2 and 1.0 micromol kg-1 DM, respectively, when plants were exposed to 1,400 micromol m-2 s-1. Levels of ABA in leaves and roots of plants exposed to 100 micromol m-2 s-1 were 0.65 and 0.55 micromol kg-1 DM, respectively. They were 0.24 micromol kg-1 DM (both leaves and roots) when plants were exposed to 1,400 micromol m-2 s-1. Levels of isopentenyl adenosine in leaves (24.3 nmol kg-1 DM) and roots (29.9 nmol kg-1 DM) were not affected by differences in the irradiance regime. Similar values were obtained in a second experiment. Other cytokinins could not be detected (<10 nmol kg 1 DM) in either experiment with the sample sizes used (150-600 mg DM for roots and shoots, respectively).

  14. IAA multilingual space dictionary, current status and future prospects

    NASA Astrophysics Data System (ADS)

    Yoshimitsu, Tetsuo; McKenna-Lawlor, Susan; Candel, Danielle; Ninomiya, Keiken; Contant, Jean-Michel

    2015-12-01

    Terminology is a key issue for a better understanding among people using various languages. Since 1986, when the International Academy of Astronautics (IAA) multilingual terminology database committee on astronautics was formed, the committee and its successor IAA study groups on the IAA multilingual space dictionary have made a continuous effort to construct a multilingual dictionary database on astronautical terms. In 2002, the dictionary was computerized using a database server and some recent internet technologies. The database is accessible from all over the world via the internet. You can search for terms at your home and office using a web browser installed on the computer with an internet connection. Since then, the number of terms and languages included in the database has increased. The current version includes about 3500 terms in 22 languages. The flexibility of the database enables the addition and the revision of new terms without much effort. The computerization has also demonstrated another possibility to utilize the database. When total of four paper books about the multilingual space terminology were published on the 50th anniversary of IAA in 2010, one of the lexicon books was edited by a computer program which accessed to the database. In this paper, the authors present the current status of the IAA multilingual database as well as the future possibilities on the utilization of the database.

  15. Implementation and use of a highly available and innovative IaaS solution: the Cloud Area Padovana

    NASA Astrophysics Data System (ADS)

    Aiftimiei, C.; Andreetto, P.; Bertocco, S.; Biasotto, M.; Dal Pra, S.; Costa, F.; Crescente, A.; Dorigo, A.; Fantinel, S.; Fanzago, F.; Frizziero, E.; Gulmini, M.; Michelotto, M.; Sgaravatto, M.; Traldi, S.; Venaruzzo, M.; Verlato, M.; Zangrando, L.

    2015-12-01

    While in the business world the cloud paradigm is typically implemented purchasing resources and services from third party providers (e.g. Amazon), in the scientific environment there's usually the need of on-premises IaaS infrastructures which allow efficient usage of the hardware distributed among (and owned by) different scientific administrative domains. In addition, the requirement of open source adoption has led to the choice of products like OpenStack by many organizations. We describe a use case of the Italian National Institute for Nuclear Physics (INFN) which resulted in the implementation of a unique cloud service, called ’Cloud Area Padovana’, which encompasses resources spread over two different sites: the INFN Legnaro National Laboratories and the INFN Padova division. We describe how this IaaS has been implemented, which technologies have been adopted and how services have been configured in high-availability (HA) mode. We also discuss how identity and authorization management were implemented, adopting a widely accepted standard architecture based on SAML2 and OpenID: by leveraging the versatility of those standards the integration with authentication federations like IDEM was implemented. We also discuss some other innovative developments, such as a pluggable scheduler, implemented as an extension of the native OpenStack scheduler, which allows the allocation of resources according to a fair-share based model and which provides a persistent queuing mechanism for handling user requests that can not be immediately served. Tools, technologies, procedures used to install, configure, monitor, operate this cloud service are also discussed. Finally we present some examples that show how this IaaS infrastructure is being used.

  16. Auxin Produced by the Indole-3-Pyruvic Acid Pathway Regulates Development and Gemmae Dormancy in the Liverwort Marchantia polymorpha.

    PubMed

    Eklund, D Magnus; Ishizaki, Kimitsune; Flores-Sandoval, Eduardo; Kikuchi, Saya; Takebayashi, Yumiko; Tsukamoto, Shigeyuki; Hirakawa, Yuki; Nonomura, Maiko; Kato, Hirotaka; Kouno, Masaru; Bhalerao, Rishikesh P; Lagercrantz, Ulf; Kasahara, Hiroyuki; Kohchi, Takayuki; Bowman, John L

    2015-06-01

    The plant hormone auxin (indole-3-acetic acid [IAA]) has previously been suggested to regulate diverse forms of dormancy in both seed plants and liverworts. Here, we use loss- and gain-of-function alleles for auxin synthesis- and signaling-related genes, as well as pharmacological approaches, to study how auxin regulates development and dormancy in the gametophyte generation of the liverwort Marchantia polymorpha. We found that M. polymorpha possess the smallest known toolkit for the indole-3-pyruvic acid (IPyA) pathway in any land plant and that this auxin synthesis pathway mainly is active in meristematic regions of the thallus. Previously a Trp-independent auxin synthesis pathway has been suggested to produce a majority of IAA in bryophytes. Our results indicate that the Trp-dependent IPyA pathway produces IAA that is essential for proper development of the gametophyte thallus of M. polymorpha. Furthermore, we show that dormancy of gemmae is positively regulated by auxin synthesized by the IPyA pathway in the apex of the thallus. Our results indicate that auxin synthesis, transport, and signaling, in addition to its role in growth and development, have a critical role in regulation of gemmae dormancy in M. polymorpha. PMID:26036256

  17. Demonstrations at School Level of the Effects of IAA

    ERIC Educational Resources Information Center

    Falk, Peter

    1973-01-01

    Describes demonstrations suitable for secondary school biology classes relating to the effects of the hormone IAA on plant growth. Demonstrations illustrate how hormone treatments affect stem elongation, callus formation, inhibition of axillary buds, stimulation of secondary growth and initiation of adventitious root development, root elongation,…

  18. Division IAA Football Players and Risk Factors for Metabolic Syndrome

    ERIC Educational Resources Information Center

    Repovich, Wendy E. S.; Babcock, Garth J.

    2012-01-01

    The purpose of this study was to determine if body composition and blood pressure (BP), two markers for Metabolic Syndrome (MetS), were correlated in college football players. Height, weight, BMI, systolic (SBP) and Diastolic (DBP) blood pressure and body composition (three measures) were assessed in a Division IAA football team (N = 55). Data…

  19. GA4 and IAA were involved in the morphogenesis and development of flowers in Agapanthus praecox ssp. orientalis.

    PubMed

    Zhang, Di; Ren, Li; Yue, Jian-hua; Wang, Ling; Zhuo, Li-huan; Shen, Xiao-hui

    2014-07-01

    The transition from vegetative to reproductive growth represents a major phase change in angiosperms. Hormones play important roles in this process. In this study, gibberellic acid (GA), cytokinins (CKs), indoleacetic acid (IAA), and abscisic acid (ABA) were analyzed during the flowering in Agapanthus praecox ssp. orientalis. Eleven types of endogenous gibberellins in addition to GA1 were detected in various organs. GA9 was detected with the highest concentrations, followed by GA5, GA8, and GA19. However, GA4 was the main bioactive GA that was involved in the regulation of flowering. Eight types of endogenous cytokinins were detected in A. praecox ssp. orientalis, and zeatin, zeatin riboside, zeatin-O-glucoside, and N(6)-isopentenyladenosine-5-monophosphate were present at higher levels throughout the study, of which zeatin plays an important role in the development of various organs. IAA increased by 581% in the shoot tips from the vegetative to inflorescence bud stages and had the most significant changes during flowering. Phytohormone immunolocalization analysis suggested that IAA involved in differentiation and development of each floral organs, GA and zeatin play important roles in floret primordia differentiation and ovule development. Using exogenous plant growth regulators proved that GA signaling regulate the scape elongation and stimulate early-flowering, and IAA signaling is involved in the pedicel and corolla elongation and delay flowering slightly. PMID:24913054

  20. Auxin Produced by the Indole-3-Pyruvic Acid Pathway Regulates Development and Gemmae Dormancy in the Liverwort Marchantia polymorpha[OPEN

    PubMed Central

    Eklund, D. Magnus; Ishizaki, Kimitsune; Flores-Sandoval, Eduardo; Kikuchi, Saya; Takebayashi, Yumiko; Tsukamoto, Shigeyuki; Hirakawa, Yuki; Nonomura, Maiko; Kato, Hirotaka; Kouno, Masaru; Bhalerao, Rishikesh P.; Lagercrantz, Ulf; Kasahara, Hiroyuki; Kohchi, Takayuki; Bowman, John L.

    2015-01-01

    The plant hormone auxin (indole-3-acetic acid [IAA]) has previously been suggested to regulate diverse forms of dormancy in both seed plants and liverworts. Here, we use loss- and gain-of-function alleles for auxin synthesis- and signaling-related genes, as well as pharmacological approaches, to study how auxin regulates development and dormancy in the gametophyte generation of the liverwort Marchantia polymorpha. We found that M. polymorpha possess the smallest known toolkit for the indole-3-pyruvic acid (IPyA) pathway in any land plant and that this auxin synthesis pathway mainly is active in meristematic regions of the thallus. Previously a Trp-independent auxin synthesis pathway has been suggested to produce a majority of IAA in bryophytes. Our results indicate that the Trp-dependent IPyA pathway produces IAA that is essential for proper development of the gametophyte thallus of M. polymorpha. Furthermore, we show that dormancy of gemmae is positively regulated by auxin synthesized by the IPyA pathway in the apex of the thallus. Our results indicate that auxin synthesis, transport, and signaling, in addition to its role in growth and development, have a critical role in regulation of gemmae dormancy in M. polymorpha. PMID:26036256

  1. Exogenous IAA differentially affects growth, oxidative stress and antioxidants system in Cd stressed Trigonella foenum-graecum L. seedlings: Toxicity alleviation by up-regulation of ascorbate-glutathione cycle.

    PubMed

    Bashri, Gausiya; Prasad, Sheo Mohan

    2016-10-01

    In the present study, effect of exogenous indole-3-acetic acid at their different levels (i.e. low; IAAL, 10µM and high; IAAH, 100µM) were studied on growth, oxidative stress biomarkers and antioxidant enzymes (SOD, POD, CAT and GST), and metabolites (AsA and GSH) as well as enzymes (APX, GR and DHAR) of ascorbate-glutathione cycle in Trigonella foenum-graecum L. seedlings grown under cadmium (Cd1, 3mgCd kg(-1) soil and Cd2, 9mgCd kg(-1) soil) stress. Cadmium (Cd) at both doses caused reduction in growth which was correlated with enhanced lipid peroxidation and damage to membrane as a result of excess accumulation of O2(•-) and H2O2. Cd also enhanced the oxidation of AsA and GSH to DHA and GSSG, respectively which give a clear sign of oxidative stress, despite of accelerated activity of enzymatic antioxidants: SOD, CAT, POD, GST as well as APX, DHAR (except in Cd2 stress) and GR. Exogenous application of IAAL resulted further rise in the activities of these enzymes, and maintained the redox status (> ratios: AsA/DHA and GSH/GSSG) of cells. The maintained redox status of cells under IAAL treatment declined the level of ROS in Cd1 and Cd2 treated seedlings thereby alleviated the Cd toxicity and this effect was more pronounced under Cd1 stress. Contrary to this, exogenous IAAH suppressed the activity of DHAR and GR and disturbed the redox status (< ratios: AsA/DHA and GSH/GSSG) of cells, hence excess accumulation of ROS further aggravated the Cd induced damage. Thus, overall results suggest that IAA at low (IAAL) and high (IAAH) doses affected the Cd toxicity differently by regulating the ascorbate-glutathione cycle as well as activity of other antioxidants in Trigonella seedlings. PMID:27344401

  2. Effects of Kinetin, IAA, and Gibberellin on Ethylene Production, and Their Interactions in Growth of Seedlings.

    PubMed

    Fuchs, Y; Lieberman, M

    1968-12-01

    Kinetin in concentrations of 10(-8) to 10(-4)m, stimulated ethylene production in 3 and 4-day old etiolated seedlings of Alaska pea (Pisum sativum L. var. Alaska). Seedlings of other species responded similarly. The response to kinetin depended on the age of the seedlings.Kinetin alone did not influence ethylene production in 6-day old stem sections, but it greatly increased the enhancing effect of IAA.Gibberellic acid had no effect on ethylene production by pea seedlings during the first 6 days of growth. Ethylene and gibberellic acid are antagonistic in their effects on growth of the seedlings; ethylene interfered severely with the action of gibberellic acid but did not completely suppress it.The inhibitors cycloheximide, cupferron, and N-ethylmaleimide, caused considerable inhibition of kinetin-induced ethylene production but were much less effective in the endogenous ethylene-forming system. PMID:16657004

  3. Effects of abscisic acid and xanthoxin on elongation and gravitropism in primary roots of Zea mays

    NASA Technical Reports Server (NTRS)

    Lee, J. S.; Hasenstein, K. H.; Mulkey, T. J.; Yang, R. L.; Evans, M. L.

    1990-01-01

    We examined the involvement of abscisic acid (ABA) and xanthoxin (Xan) in maize root gravitropism by (1) testing the ability of ABA to allow positive gravitropism in dark-grown seedlings of the maize cultivar LG11, a cultivar known to require light for positive gravitropism of the primary root, (2) comparing curvature in roots in which half of the cap had been excised and replaced with agar containing either ABA or indole-3-acetic acid (IAA), (3) measuring gravitropism in roots of seedlings submerged in oxygenated solutions of ABA or IAA and (4) testing the effect of Xan on root elongation. Using a variety of methods of applying ABA to the root, we found that ABA did not cause horizontally-oriented primary roots of dark-grown seedlings to become positively gravitropic. Replacing half of the root cap of vertically oriented roots with an agar block containing ABA had little or no effect on curvature relative to that of controls in which the half cap was replaced by a plain agar block. Replacement of the removed half cap with IAA either canceled or reversed the curvature displayed by controls. When light-grown seedlings were submerged in ABA they responded strongly to gravistimulation while those in IAA did not. Xan (up to 0.1 mM) did not affect root elongation. The results indicate that ABA is not a likely mediator of root gravitropism and that the putative ABA precursor, Xan, lacks the appropriate growth-inhibiting properties to serve as a mediator of root gravitropism.

  4. Auxin promotes susceptibility to Pseudomonas syringae via a mechanism independent of suppression of salicylic acid-mediated defenses.

    PubMed

    Mutka, Andrew M; Fawley, Stephen; Tsao, Tiffany; Kunkel, Barbara N

    2013-06-01

    Auxin is a key plant growth regulator that also impacts plant-pathogen interactions. Several lines of evidence suggest that the bacterial plant pathogen Pseudomonas syringae manipulates auxin physiology in Arabidopsis thaliana to promote pathogenesis. Pseudomonas syringae strategies to alter host auxin biology include synthesis of the auxin indole-3-acetic acid (IAA) and production of virulence factors that alter auxin responses in host cells. The application of exogenous auxin enhances disease caused by P. syringae strain DC3000. This is hypothesized to result from antagonism between auxin and salicylic acid (SA), a major regulator of plant defenses, but this hypothesis has not been tested in the context of infected plants. We further investigated the role of auxin during pathogenesis by examining the interaction of auxin and SA in the context of infection in plants with elevated endogenous levels of auxin. We demonstrated that elevated IAA biosynthesis in transgenic plants overexpressing the YUCCA 1 (YUC1) auxin biosynthesis gene led to enhanced susceptibility to DC3000. Elevated IAA levels did not interfere significantly with host defenses, as effector-triggered immunity was active in YUC1-overexpressing plants, and we observed only minor effects on SA levels and SA-mediated responses. Furthermore, a plant line carrying both the YUC1-overexpression transgene and the salicylic acid induction deficient 2 (sid2) mutation, which impairs SA synthesis, exhibited additive effects of enhanced susceptibility from both elevated auxin levels and impaired SA-mediated defenses. Thus, in IAA overproducing plants, the promotion of pathogen growth occurs independently of suppression of SA-mediated defenses. PMID:23521356

  5. An Auxin-Conjugated Strawberry Fruit Protein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strawberry fruit contain indole-3-acetic acid (IAA) covalently attached to specific strawberry proteins. Immunoblotting using a specific antibody to IAA-glycine linked to BSA detected IAA proteins in both achenes and receptacles. Protein-conjugated IAA accounts for the majority of the total IAA pool...

  6. IAA transport in corn roots includes the root cap

    SciTech Connect

    Hasenstein, K.H. )

    1989-04-01

    In earlier reports we concluded that auxin is the growth regulator that controls gravicurvature in roots and that the redistribution of auxin occurs within the root cap. Since other reports did not detect auxin in the root cap, we attempted to confirm the IAA does move through the cap. Agar blocks containing {sup 3}H-IAA were applied to the cut surface of 5 mm long apical segments of primary roots of corn (mo17xB73). After 30 to 120 min radioactivity (RA) of the cap and root tissue was determined. While segments suspended in water-saturated air accumulated very little RA in the cap, application of 0.5 {mu}1 of dist. water to the cap (=controls) increased RA of the cap dramatically. Application to the cap of 0.5 {mu}1 of sorbitol or the Ca{sup 2+} chelator EGTA reduced cap RA to 46% and 70% respectively compared to water, without affecting uptake. Control root segments gravireacted faster than non-treated or osmoticum or EGTA treated segments. The data indicate that both the degree of hydration and calcium control the amount of auxin moving through the cap.

  7. ACC deaminase and IAA producing growth promoting bacteria from the rhizosphere soil of tropical rice plants.

    PubMed

    Bal, Himadri Bhusan; Das, Subhasis; Dangar, Tushar K; Adhya, Tapan K

    2013-12-01

    Beneficial plant-associated bacteria play a key role in supporting and/or promoting plant growth and health. Plant growth promoting bacteria present in the rhizosphere of crop plants can directly affect plant metabolism or modulate phytohormone production or degradation. We isolated 355 bacteria from the rhizosphere of rice plants grown in the farmers' fields in the coastal rice field soil from five different locations of the Ganjam district of Odisha, India. Six bacteria producing both ACC deaminase (ranging from 603.94 to 1350.02 nmol α-ketobutyrate mg(-1)  h(-1) ) and indole acetic acid (IAA; ranging from 10.54 to 37.65 μM ml(-1) ) in pure cultures were further identified using polyphasic taxonomy including BIOLOG((R)) , FAME analysis and the 16S rRNA gene sequencing. Phylogenetic analyses of the isolates resulted into five major clusters to include members of the genera Bacillus, Microbacterium, Methylophaga, Agromyces, and Paenibacillus. Seed inoculation of rice (cv. Naveen) by the six individual PGPR isolates had a considerable impact on different growth parameters including root elongation that was positively correlated with ACC deaminase activity and IAA production. The cultures also had other plant growth attributes including ammonia production and at least two isolates produced siderophores. Study indicates that presence of diverse rhizobacteria with effective growth-promoting traits, in the rice rhizosphere, may be exploited for a sustainable crop management under field conditions. PMID:23681643

  8. cis-Cinnamic acid selective suppressors distinct from auxin inhibitors.

    PubMed

    Okuda, Katsuhiro; Nishikawa, Keisuke; Fukuda, Hiroshi; Fujii, Yoshiharu; Shindo, Mitsuru

    2014-01-01

    The activity of cis-cinnamic acid (cis-CA), one of the allelochemicals, in plants is very similar to that of indole-3-acetic acid (IAA), a natural auxin, and thus cis-CA has long been believed to be an analog of auxin. We have reported some structure-activity relationships studies by synthesizing over 250 cis-CA derivatives and estimating their inhibitory activities on root growth inhibition in lettuce. In this study, the compounds that showed low- or no-activity on root growth inhibition were recruited as candidates suppressors against cis-CA and/or auxin and tested for their activity. In the presence of cis-CA, lettuce root growth was inhibited; however, the addition of some cis-CA derivatives restored control-level root growth. Four compounds, (Z)-3-(4-isopropylphenyl)acrylic acid, (Z)-3-(3-butoxyphenyl)acrylic acid, (Z)-3-[3-(pentyloxy)phenyl]acrylic acid, and (Z)-3-(naphthalen-1-yl)acrylic acid were selected as candidates for a cis-CA selective suppressor they allowed the recovery of root growth from inhibition by cis-CA treatment without any effects on the IAA-induced effect or elongating activity by themselves. Three candidates significantly ameliorated the root shortening by the potent inhibitor derived from cis-CA. In brief, we have found some cis-CA selective suppressors which have never been reported from inactive cis-CA derivatives for root growth inhibition. cis-CA selective suppressors will play an important role in elucidating the mechanism of plant growth regulation. PMID:24881667

  9. Characterization of an Indole-3-Acetamide Hydrolase from Alcaligenes faecalis subsp. parafaecalis and Its Application in Efficient Preparation of Both Enantiomers of Chiral Building Block 2,3-Dihydro-1,4-Benzodioxin-2-Carboxylic Acid.

    PubMed

    Mishra, Pradeep; Kaur, Suneet; Sharma, Amar Nath; Jolly, Ravinder S

    2016-01-01

    Both the enantiomers of 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid are valuable chiral synthons for enantiospecific synthesis of therapeutic agents such as (S)-doxazosin mesylate, WB 4101, MKC 242, 2,3-dihydro-2-hydroxymethyl-1,4-benzodioxin, and N-[2,4-oxo-1,3-thiazolidin-3-yl]-2,3-dihydro-1,4-benzodioxin-2-carboxamide. Pharmaceutical applications require these enantiomers in optically pure form. However, currently available methods suffer from one drawback or other, such as low efficiency, uncommon and not so easily accessible chiral resolving agent and less than optimal enantiomeric purity. Our interest in finding a biocatalyst for efficient production of enantiomerically pure 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid lead us to discover an amidase activity from Alcaligenes faecalis subsp. parafaecalis, which was able to kinetically resolve 2,3-dihydro-1,4-benzodioxin-2-carboxyamide with E value of >200. Thus, at about 50% conversion, (R)-2,3-dihydro-1,4-benzodioxin-2-carboxylic acid was produced in >99% e.e. The remaining amide had (S)-configuration and 99% e.e. The amide and acid were easily separated by aqueous (alkaline)-organic two phase extraction method. The same amidase was able to catalyse, albeit at much lower rate the hydrolysis of (S)-amide to (S)-acid without loss of e.e. The amidase activity was identified as indole-3-acetamide hydrolase (IaaH). IaaH is known to catalyse conversion of indole-3-acetamide (IAM) to indole-3-acetic acid (IAA), which is phytohormone of auxin class and is widespread among plants and bacteria that inhabit plant rhizosphere. IaaH exhibited high activity for 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which was about 65% compared to its natural substrate, indole-3-acetamide. The natural substrate for IaaH indole-3-acetamide shared, at least in part a similar bicyclic structure with 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which may account for high activity of enzyme towards this un-natural substrate. To the best of

  10. Characterization of an Indole-3-Acetamide Hydrolase from Alcaligenes faecalis subsp. parafaecalis and Its Application in Efficient Preparation of Both Enantiomers of Chiral Building Block 2,3-Dihydro-1,4-Benzodioxin-2-Carboxylic Acid

    PubMed Central

    Mishra, Pradeep; Kaur, Suneet; Sharma, Amar Nath; Jolly, Ravinder S.

    2016-01-01

    Both the enantiomers of 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid are valuable chiral synthons for enantiospecific synthesis of therapeutic agents such as (S)-doxazosin mesylate, WB 4101, MKC 242, 2,3-dihydro-2-hydroxymethyl-1,4-benzodioxin, and N-[2,4-oxo-1,3-thiazolidin-3-yl]-2,3-dihydro-1,4-benzodioxin-2-carboxamide. Pharmaceutical applications require these enantiomers in optically pure form. However, currently available methods suffer from one drawback or other, such as low efficiency, uncommon and not so easily accessible chiral resolving agent and less than optimal enantiomeric purity. Our interest in finding a biocatalyst for efficient production of enantiomerically pure 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid lead us to discover an amidase activity from Alcaligenes faecalis subsp. parafaecalis, which was able to kinetically resolve 2,3-dihydro-1,4-benzodioxin-2-carboxyamide with E value of >200. Thus, at about 50% conversion, (R)-2,3-dihydro-1,4-benzodioxin-2-carboxylic acid was produced in >99% e.e. The remaining amide had (S)-configuration and 99% e.e. The amide and acid were easily separated by aqueous (alkaline)-organic two phase extraction method. The same amidase was able to catalyse, albeit at much lower rate the hydrolysis of (S)-amide to (S)-acid without loss of e.e. The amidase activity was identified as indole-3-acetamide hydrolase (IaaH). IaaH is known to catalyse conversion of indole-3-acetamide (IAM) to indole-3-acetic acid (IAA), which is phytohormone of auxin class and is widespread among plants and bacteria that inhabit plant rhizosphere. IaaH exhibited high activity for 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which was about 65% compared to its natural substrate, indole-3-acetamide. The natural substrate for IaaH indole-3-acetamide shared, at least in part a similar bicyclic structure with 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which may account for high activity of enzyme towards this un-natural substrate. To the best of

  11. Phloem-specific expression of a melon Aux/IAA in tomato plants alters auxin sensitivity and plant development

    PubMed Central

    Golan, Guy; Betzer, Rotem; Wolf, Shmuel

    2013-01-01

    Phloem sap contains a large repertoire of macromolecules in addition to sugars, amino acids, growth substances and ions. The transcription profile of melon phloem sap contains over 1000 mRNA molecules, most of them associated with signal transduction, transcriptional control, and stress and defense responses. Heterografting experiments have established the long-distance trafficking of numerous mRNA molecules. Interestingly, several trafficking transcripts are involved in the auxin response, including two molecules coding for auxin/indole acetic acid (Aux/IAA). To further explore the biological role of the melon Aux/IAA transcript CmF-308 in the vascular tissue, a cassette containing the coding sequence of this gene under a phloem-specific promoter was introduced into tomato plants. The number of lateral roots was significantly higher in transgenic plants expressing CmF-308 under the AtSUC2 promoter than in controls. A similar effect on root development was obtained after transient expression of CmF-308 in source leaves of N. benthamiana plants. An auxin-response assay showed that CmF-308-transgenic roots are more sensitive to auxin than control roots. In addition to the altered root development, phloem-specific expression of CmF-308 resulted in shorter plants, a higher number of lateral shoots and delayed flowering, a phenotype resembling reduced apical dominance. In contrast to the root response, cotyledons of the transgenic plants were less sensitive to auxin than control cotyledons. The reduced auxin sensitivity in the shoot tissue was confirmed by lower relative expression of several Aux/IAA genes in leaves and an increase in the relative expression of a cytokinin-response regulator, TRR8/9b. The accumulated data suggest that expression of Aux/IAA in the phloem modifies auxin sensitivity in a tissue-specific manner, thereby altering plant development. PMID:23986770

  12. An attempt to localize and identify the gravity sensing mechanism of plants

    NASA Technical Reports Server (NTRS)

    Bandurski, R. S.

    1984-01-01

    Gravistimulation causes an asymmetric distribution of the plant growth hormone, indole-3-acetic acid (IAA). In what tissue of the plant the IAA asymmetry arises will be determined so as to better localize the gravity sensing device.

  13. Bioactives derived from ripe corn tassels: a possible new natural skin whitener, 4-hydroxy-1-oxindole-3-acetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previously, we showed that extracts of ripe seasonal sweet corn tassels possess anti-irritant and anti-oxidant activities. The chemical identification of corn tassel bioactives were investigated by HPLC analysis. The hydroalcoholic extracts are composed primarily (>85%) phenolic-type compounds. The ...

  14. Stimulatory effect of cytokinins and interaction with IAA on the release of lateral buds of pea plants from apical dominance.

    PubMed

    Li, Chunjian; Bangerth, Fritz

    2003-09-01

    Lateral buds of pea plants can be released from apical dominance and even be transformed into dominant shoots when repeatedly treated with synthetic exogenous cytokinins (CKs). The mechanism of the effect of CKs, however, is not clear. The results in this work showed that the stimulatory effects of CKs on the growth of lateral buds and the increase in their fresh weights in pea plants depended on the structure and concentration of the CKs used. The effect of N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) was stronger than that of 6-benzylaminopurine (6-BA). Indoleacetic acid (IAA) concentration in shoot, IAA export out of the treated apex and basipetal transport in stems were markedly increased after the application of CPPU or 6-BA to the apex or the second node of pea plant. This increase was positively correlated with the increased concentration of the applied CKs. These results suggest that the increased IAA synthesis and export induced by CKs application might be responsible for the growth of lateral shoots in intact pea plants. PMID:14593807

  15. The IAA Cosmic Study 'Protecting the Environment of Celestial Bodies'

    NASA Astrophysics Data System (ADS)

    Rettberg, Petra; Hofmann, Mahulena; Williamson, Mark

    The study group tasked with producing this International Academy of Astronautics (IAA) `Cosmic Study' on Protecting the Environment of Celestial Bodies was formed under the aus-pices of IAA Commission V (Space Policy, Law Economy). The members of the international, multidisciplinary team assembled to undertake the Study accept, as a premise, the Planetary Protection Policy guidelines developed by COSPAR, which differentiate the degree of protec-tion according to the type of space activity and the celestial body under investigation (such that fly-by missions have less stringent requirements than lander missions, while Mars is `better protected' than the Moon). However, this Study goes deliberately beyond the interpretation of `Planetary Protection' as a set of methods for protecting the planets from biological con-tamination and extends consideration to the geophysical, industrial and cultural realms. The Study concludes that, from the perspective of current and future activities in outer space, present measures aimed at protecting the space environment are insufficient. Deficiencies in-clude a lack of suitable in-situ methods of chemical and biological detection and the absence of a systematic record of radioactive contaminants. Other issues identified by the Study include an insufficient legal framework, a shortage of effective economic tools and a lack of political will to address these concerns. It is expected that new detection methods under development, and the resultant increase in microbiological knowledge of the planetary surfaces, will lead to changes in the COSPAR planetary protection guidelines and bioburden limits. It is important, however, that any new approaches should not hamper future exploration and exploitation of celestial bodies more than absolutely necessary. The Study addresses the need to find a balance between protection and freedom of action. From a legal perspective, the Study concludes that a general consensus on protection of the

  16. The Arabidopsis YUCCA1 Flavin Monooxygenase Functions in the Indole-3-Pyruvic Acid Branch of Auxin Biosynthesis[W

    PubMed Central

    Stepanova, Anna N.; Yun, Jeonga; Robles, Linda M.; Novak, Ondrej; He, Wenrong; Guo, Hongwei; Ljung, Karin; Alonso, Jose M.

    2011-01-01

    The effects of auxins on plant growth and development have been known for more than 100 years, yet our understanding of how plants synthesize this essential plant hormone is still fragmentary at best. Gene loss- and gain-of-function studies have conclusively implicated three gene families, CYTOCHROME P450 79B2/B3 (CYP79B2/B3), YUCCA (YUC), and TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1/TRYPTOPHAN AMINOTRANSFERASE-RELATED (TAA1/TAR), in the production of this hormone in the reference plant Arabidopsis thaliana. Each of these three gene families is believed to represent independent routes of auxin biosynthesis. Using a combination of pharmacological, genetic, and biochemical approaches, we examined the possible relationships between the auxin biosynthetic pathways defined by these three gene families. Our findings clearly indicate that TAA1/TARs and YUCs function in a common linear biosynthetic pathway that is genetically distinct from the CYP79B2/B3 route. In the redefined TAA1-YUC auxin biosynthetic pathway, TAA1/TARs are required for the production of indole-3-pyruvic acid (IPyA) from Trp, whereas YUCs are likely to function downstream. These results, together with the extensive genetic analysis of four pyruvate decarboxylases, the putative downstream components of the TAA1 pathway, strongly suggest that the enzymatic reactions involved in indole-3-acetic acid (IAA) production via IPyA are different than those previously postulated, and a new and testable model for how IAA is produced in plants is needed. PMID:22108406

  17. Possible involvement of abscisic acid in the induction of secondary somatic embryogenesis on seed-coat-derived carrot somatic embryos.

    PubMed

    Ogata, Yumiko; Iizuka, Misato; Nakayama, Daisuke; Ikeda, Miho; Kamada, Hiroshi; Koshiba, Tomokazu

    2005-06-01

    When seed coats (pericarps) were picked from 14-day-old carrot (Daucus carota) seedlings and cultured on agar plates, embryogenic cell clusters were produced very rapidly at a high frequency on the open side edge. Embryo induction progressed without auxin treatment; indeed treatment caused the formation of non-embryogenic callus. The embryogenic tissues (primary embryos) developed normally until the torpedo stage; however, after this a number of secondary somatic embryos were produced in the hypocotyl and root regions. "Tertiary" embryos were formed on some of the secondary embryos, but many developed into normal plantlets. The primary embryos contained significantly higher levels of abscisic acid (ABA) than the hypocotyl-derived normal and seed-coat-derived secondary embryos. Fluridone inhibited the induction of secondary embryogenesis, while exogenously supplied ABA induced not only "tertiary" embryogenesis on the seed-coat-derived secondary embryos, but also secondary embryos on the hypocotyl-derived normal somatic embryos. These results indicate that ABA is one of the important endogenous factors for the induction of secondary embryogenesis on carrot somatic embryos. Higher levels of indole-3-acetic acid (IAA) in primary embryos also suggest the presence of some concerted effect of ABA and IAA on the induction of secondary embryogenesis in primary embryos. PMID:15770487

  18. Abscisic Acid Is a General Negative Regulator of Arabidopsis Axillary Bud Growth1[OPEN

    PubMed Central

    Yao, Chi; Finlayson, Scott A.

    2015-01-01

    Branching is an important process controlled by intrinsic programs and by environmental signals transduced by a variety of plant hormones. Abscisic acid (ABA) was previously shown to mediate Arabidopsis (Arabidopsis thaliana) branching responses to the ratio of red light (R) to far-red light (FR; an indicator of competition) by suppressing bud outgrowth from lower rosette positions under low R:FR. However, the role of ABA in regulating branching more generally was not investigated. This study shows that ABA restricts lower bud outgrowth and promotes correlative inhibition under both high and low R:FR. ABA was elevated in buds exhibiting delayed outgrowth resulting from bud position and low R:FR and decreased in elongating buds. ABA was reduced in lower buds of hyperbranching mutants deficient in auxin signaling (AUXIN RESISTANT1), MORE AXILLARY BRANCHING (MAX) signaling (MAX2), and BRANCHED1 (BRC1) function, and partial suppression of branch elongation in these mutants by exogenous ABA suggested that ABA may act downstream of these components. Bud BRC1 expression was not altered by exogenous ABA, consistent with a downstream function for ABA. However, the expression of genes encoding the indole-3-acetic acid (IAA) biosynthesis enzyme TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1, the auxin transporter PIN-FORMED1, and the cell cycle genes CYCLIN A2;1 and PROLIFERATING CELL NUCLEAR ANTIGEN1 in buds was suppressed by ABA, suggesting that it may inhibit bud growth in part by suppressing elements of the cell cycle machinery and bud-autonomous IAA biosynthesis and transport. ABA was found to suppress bud IAA accumulation, thus confirming this aspect of its action. PMID:26149576

  19. Auxin-Induced Ethylene Triggers Abscisic Acid Biosynthesis and Growth Inhibition1

    PubMed Central

    Hansen, Hauke; Grossmann, Klaus

    2000-01-01

    The growth-inhibiting effects of indole-3-acetic acid (IAA) at high concentration and the synthetic auxins 7-chloro-3-methyl-8-quinolinecarboxylic acid (quinmerac), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 4-amino-3,6,6-trichloropicolinic acid (picloram), and naphthalene acetic acid, were investigated in cleavers (Galium aparine). When plants were root treated with 0.5 mm IAA, shoot epinasty and inhibition of root and shoot growth developed during 24 h. Concomitantly, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity, and ACC and ethylene production were transiently stimulated in the shoot tissue within 2 h, followed by increases in immunoreactive (+)-abscisic acid (ABA) and its precursor xanthoxal (xanthoxin) after 5 h. After 24 h of treatment, levels of xanthoxal and ABA were elevated up to 2- and 24-fold, relative to control, respectively. In plants treated with IAA, 7-chloro-3-methyl-8-quinolinecarboxylic acid, naphthalene acetic acid, 2-methoxy-3,6-dichlorobenzoic acid, and 4-amino-3,6,6-trichloropicolinic acid, levels of ethylene, ACC, and ABA increased in close correlation with inhibition of shoot growth. Aminoethoxyvinyl-glycine and cobalt ions, which inhibit ethylene synthesis, decreased ABA accumulation and growth inhibition, whereas the ethylene-releasing ethephon promoted ABA levels and growth inhibition. In accordance, tomato mutants defective in ethylene perception (never ripe) did not produce the xanthoxal and ABA increases and growth inhibition induced by auxins in wild-type plants. This suggests that auxin-stimulated ethylene triggers ABA accumulation and the consequent growth inhibition. Reduced catabolism most probably did not contribute to ABA increase, as indicated by immunoanalyses of ABA degradation and conjugation products in shoot tissue and by pulse experiments with [3H]-ABA in cell suspensions of G. aparine. In contrast, studies using inhibitors of ABA biosynthesis (fluridone, naproxen, and tungstate), ABA

  20. The optimal design of service level agreement in IAAS based on BDIM

    NASA Astrophysics Data System (ADS)

    Liu, Xiaochen; Zhan, Zhiqiang

    2013-03-01

    Cloud Computing has become more and more prevalent over the past few years, and we have seen the importance of Infrastructure-as-a-service (IaaS). This kind of service enables scaling of bandwidth, memory, computing power and storage. But the SLA in IaaS also faces complexity and variety. Users also consider the business of the service. To meet the most users requirements, a methodology for designing optimal SLA in IaaS from the business perspectives is proposed. This method is different from the conventional SLA design method, It not only focuses on service provider perspective, also from the customer to carry on the design. This methodology better captures the linkage between service provider and service client by considering minimizing the business loss originated from performance degradation and IT infrastructure failures and maximizing profits for service provider and clients. An optimal design in an IaaS model is provided and an example are analyzed to show this approach obtain higher profit.

  1. Effect of gibberellic acid on growth and indole metabolism of dwarf-pea plants

    SciTech Connect

    Husain, Z.

    1987-01-01

    A study was conducted to describe the pathway of biosynthesis of indole-3-acetic acid (IAA) from tryptophan (TPP) and determine the effect of gibberellic acid (GA/sub 3/) on this system. Treatment of dwarf peas (Pisum sativum L. var Little Marvel) with 0.8 ..mu..g GA/sub 3//plant resulted in increase in plant height along with increased auxin level. A cell-free preparation of pea shoot tissue was able to convert D,L-tryptophan-3-/sup 14/C into different indole metabolites. The acidic and neutral fractions obtained after TPP incubation were subjected to thin-layer chromatography. In the neutral fraction, two peaks of radioactivity were found and these matched the Rfs for indole-acetaldehyde (IAAId) and indole-3-ethanol (IEt). One major peak of radioactivity was observed in the radiochromatograms of the acidic fraction and it corresponded with a authentic IAA. The enzymes involved in the conversion of TPP to IAA involved, in the first step, a transaminase (tryptophan aminotransferase, EC 2 x 6 x 1) reaction. The aminotransferase was purified about 82-fold by acetone precipitation and Sephadex G-200 filtration. It had a pH optimum of 8.5 and a temperature optimum of 40/sup 0/C. With ..cap alpha..-ketoglutarate a co-substrate, the enzyme transaminated aromatic as well as aliphatic amino acids including D,L-tryptophan, D,L-alanine and D,L leucine. D-TPP was found to be more effective than L-TPP as a substrate. GA/sub 3/ treatment to dwarf pea plants results in increase in the specific activity of the enzyme over the observation period. In the second step of TPP conversion, IPyA is decarboxylated by an enzyme to IAAId. In plants treated with GA/sub 3/, the enzyme activity was significantly higher three days after treatment but remained unaffected at all other stages when observations were made. The final step enzyme is a dehydrogenase that can convert IAAId to IAA in the presence of MAD as a co-factor.

  2. Polyamines, IAA and ABA during germination in two recalcitrant seeds: Araucaria angustifolia (Gymnosperm) and Ocotea odorifera (Angiosperm)

    PubMed Central

    Pieruzzi, Fernanda P.; Dias, Leonardo L. C.; Balbuena, Tiago S.; Santa-Catarina, Claudete; dos Santos, André L. W.; Floh, Eny I. S.

    2011-01-01

    Background and Aims Plant growth regulators play an important role in seed germination. However, much of the current knowledge about their function during seed germination was obtained using orthodox seeds as model systems, and there is a paucity of information about the role of plant growth regulators during germination of recalcitrant seeds. In the present work, two endangered woody species with recalcitrant seeds, Araucaria angustifolia (Gymnosperm) and Ocotea odorifera (Angiosperm), native to the Atlantic Rain Forest, Brazil, were used to study the mobilization of polyamines (PAs), indole-acetic acid (IAA) and abscisic acid (ABA) during seed germination. Methods Data were sampled from embryos of O. odorifera and embryos and megagametophytes of A. angustifolia throughout the germination process. Biochemical analyses were carried out in HPLC. Key Results During seed germination, an increase in the (Spd + Spm) : Put ratio was recorded in embryos in both species. An increase in IAA and PA levels was also observed during seed germination in both embryos, while ABA levels showed a decrease in O. odorifera and an increase in A. angustifolia embryos throughout the period studied. Conclusions The (Spd + Spm) : Put ratio could be used as a marker for germination completion. The increase in IAA levels, prior to germination, could be associated with variations in PA content. The ABA mobilization observed in the embryos could represent a greater resistance to this hormone in recalcitrant seeds, in comparison to orthodox seeds, opening a new perspective for studies on the effects of this regulator in recalcitrant seeds. The gymnosperm seed, though without a connective tissue between megagametophyte and embryo, seems to be able to maintain communication between the tissues, based on the likely transport of plant growth regulators. PMID:21685432

  3. Validation of MIPAS IMK/IAA methane profiles

    NASA Astrophysics Data System (ADS)

    Laeng, A.; Plieninger, J.; von Clarmann, T.; Grabowski, U.; Stiller, G.; Eckert, E.; Glatthor, N.; Haenel, F.; Kellmann, S.; Kiefer, M.; Linden, A.; Lossow, S.; Deaver, L.; Engel, A.; Hervig, M.; Levin, I.; McHugh, M.; Noël, S.; Toon, G.; Walker, K.

    2015-06-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) was an infra-red (IR) limb emission spectrometer on the Envisat platform. It measured during day and night, pole-to-pole, over an altitude range from 6 to 70 km in nominal mode and up to 170 km in special modes, depending on the measurement mode, producing more than 1000 profiles day-1. We present the results of a validation study of methane version V5R_CH4_222 retrieved with the IMK/IAA MIPAS scientific level 2 processor. The level 1 spectra are provided by ESA, the version 5 was used. The time period covered corresponds to the period when MIPAS measured at reduced spectral resolution, i.e. 2005-2012. The comparison with satellite instruments includes the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), the HALogen Occultation Experiment (HALOE), the Solar Occultation For Ice Experiment (SOFIE) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). Furthermore, comparisons with MkIV balloon-borne solar occultation measurements and with air sampling measurements performed by the University of Frankfurt are presented. The validation activities include bias determination, in selected cases, assessment of histograms and comparison of corresponding climatologies. Above 50 km altitude, MIPAS methane mixing ratios agree within 3% with ACE-FTS and SOFIE. Between 30 and 40 km an agreement within 3% with SCIAMACHY has been found. In the middle stratosphere, there is no clear indication of a MIPAS bias since comparisons with various instruments contradict each other. In the lower stratosphere (below about 25-30 km) MIPAS CH4 is biased high with respect to satellite instruments, and the most likely estimate of this bias is 14%. However, in the comparison with CH4 data obtained from cryosampler measurements, there is no evidence of a MIPAS high bias between 20 and 25 km altitude. Precision validation is performed on collocated MIPAS-MIPAS pairs

  4. Validation of MIPAS IMK/IAA methane profiles

    NASA Astrophysics Data System (ADS)

    Laeng, A.; Plieninger, J.; von Clarmann, T.; Grabowski, U.; Stiller, G.; Eckert, E.; Glatthor, N.; Haenel, F.; Kellmann, S.; Kiefer, M.; Linden, A.; Lossow, S.; Deaver, L.; Engel, A.; Hervig, M.; Levin, I.; McHugh, M.; Noël, S.; Toon, G.; Walker, K.

    2015-12-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is an infrared (IR) limb emission spectrometer on the Envisat platform. It measures trace gas distributions during day and night, pole-to-pole, over an altitude range from 6 to 70 km in nominal mode and up to 170 km in special modes, depending on the measurement mode, producing more than 1000 profiles day-1. We present the results of a validation study of methane, version V5R_CH4_222, retrieved with the IMK/IAA (Institut für Meteorologie und Klimaforschung, Karlsruhe/Instituto de Astrofisica de Andalucia, Grenada) MIPAS scientific level 2 processor. The level 1 spectra are provided by the ESA (European Space Agency) and version 5 was used. The time period covered is 2005-2012, which corresponds to the period when MIPAS measured trace gas distributions at a reduced spectral resolution of 0.0625 cm-1. The comparison with satellite instruments includes the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), the HALogen Occultation Experiment (HALOE), the Solar Occultation For Ice Experiment (SOFIE) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). Furthermore, comparisons with MkIV balloon-borne solar occultation measurements and with air sampling measurements performed by the University of Frankfurt are presented. The validation activities include bias determination, assessment of stability, precision validation, analysis of histograms and comparison of corresponding climatologies. Above 50 km altitude, MIPAS methane mixing ratios agree within 3 % with ACE-FTS and SOFIE. Between 30 and 40 km an agreement within 3 % with SCIAMACHY has been found. In the middle stratosphere, there is no clear indication of a MIPAS bias since comparisons with various instruments contradict each other. In the lower stratosphere (below 25 km) MIPAS CH4 is biased high with respect to satellite instruments, and the most likely estimate of this bias is 14

  5. Aminooxy-naphthylpropionic acid and its derivatives are inhibitors of auxin biosynthesis targeting l-tryptophan aminotransferase: structure-activity relationships.

    PubMed

    Narukawa-Nara, Megumi; Nakamura, Ayako; Kikuzato, Ko; Kakei, Yusuke; Sato, Akiko; Mitani, Yuka; Yamasaki-Kokudo, Yumiko; Ishii, Takahiro; Hayashi, Ken-Ichiro; Asami, Tadao; Ogura, Takehiko; Yoshida, Shigeo; Fujioka, Shozo; Kamakura, Takashi; Kawatsu, Tsutomu; Tachikawa, Masanori; Soeno, Kazuo; Shimada, Yukihisa

    2016-08-01

    We previously reported l-α-aminooxy-phenylpropionic acid (AOPP) to be an inhibitor of auxin biosynthesis, but its precise molecular target was not identified. In this study we found that AOPP targets TRYPTOPHAN AMINOTRANSFERASE of ARABIDOPSIS 1 (TAA1). We then synthesized 14 novel compounds derived from AOPP to study the structure-activity relationships of TAA1 inhibitors in vitro. The aminooxy and carboxy groups of the compounds were essential for inhibition of TAA1 in vitro. Docking simulation analysis revealed that the inhibitory activity of the compounds was correlated with their binding energy with TAA1. These active compounds reduced the endogenous indole-3-acetic acid (IAA) content upon application to Arabidopsis seedlings. Among the compounds, we selected 2-(aminooxy)-3-(naphthalen-2-yl)propanoic acid (KOK1169/AONP) and analyzed its activities in vitro and in vivo. Arabidopsis seedlings treated with KOK1169 showed typical auxin-deficient phenotypes, which were reversed by exogenous IAA. In vitro and in vivo experiments indicated that KOK1169 is more specific for TAA1 than other enzymes, such as phenylalanine ammonia-lyase. We further tested 41 novel compounds with aminooxy and carboxy groups to which we added protection groups to increase their calculated hydrophobicity. Most of these compounds decreased the endogenous auxin level to a greater degree than the original compounds, and resulted in a maximum reduction of about 90% in the endogenous IAA level in Arabidopsis seedlings. We conclude that the newly developed compounds constitute a class of inhibitors of TAA1. We designated them 'pyruvamine'. PMID:27147230

  6. Constitutive auxin response in Physcomitrella reveals complex interactions between Aux/IAA and ARF proteins

    PubMed Central

    Lavy, Meirav; Prigge, Michael J; Tao, Sibo; Shain, Stephanie; Kuo, April; Kirchsteiger, Kerstin; Estelle, Mark

    2016-01-01

    The coordinated action of the auxin-sensitive Aux/IAA transcriptional repressors and ARF transcription factors produces complex gene-regulatory networks in plants. Despite their importance, our knowledge of these two protein families is largely based on analysis of stabilized forms of the Aux/IAAs, and studies of a subgroup of ARFs that function as transcriptional activators. To understand how auxin regulates gene expression we generated a Physcomitrella patens line that completely lacks Aux/IAAs. Loss of the repressors causes massive changes in transcription with misregulation of over a third of the annotated genes. Further, we find that the aux/iaa mutant is blind to auxin indicating that auxin regulation of transcription occurs exclusively through Aux/IAA function. We used the aux/iaa mutant as a simplified platform for studies of ARF function and demonstrate that repressing ARFs regulate auxin-induced genes and fine-tune their expression. Further the repressing ARFs coordinate gene induction jointly with activating ARFs and the Aux/IAAs. DOI: http://dx.doi.org/10.7554/eLife.13325.001 PMID:27247276

  7. Constitutive auxin response in Physcomitrella reveals complex interactions between Aux/IAA and ARF proteins.

    PubMed

    Lavy, Meirav; Prigge, Michael J; Tao, Sibo; Shain, Stephanie; Kuo, April; Kirchsteiger, Kerstin; Estelle, Mark

    2016-01-01

    The coordinated action of the auxin-sensitive Aux/IAA transcriptional repressors and ARF transcription factors produces complex gene-regulatory networks in plants. Despite their importance, our knowledge of these two protein families is largely based on analysis of stabilized forms of the Aux/IAAs, and studies of a subgroup of ARFs that function as transcriptional activators. To understand how auxin regulates gene expression we generated a Physcomitrella patens line that completely lacks Aux/IAAs. Loss of the repressors causes massive changes in transcription with misregulation of over a third of the annotated genes. Further, we find that the aux/iaa mutant is blind to auxin indicating that auxin regulation of transcription occurs exclusively through Aux/IAA function. We used the aux/iaa mutant as a simplified platform for studies of ARF function and demonstrate that repressing ARFs regulate auxin-induced genes and fine-tune their expression. Further the repressing ARFs coordinate gene induction jointly with activating ARFs and the Aux/IAAs. PMID:27247276

  8. Graphene oxide modulates root growth of Brassica napus L. and regulates ABA and IAA concentration.

    PubMed

    Cheng, Fan; Liu, Yu-Feng; Lu, Guang-Yuan; Zhang, Xue-Kun; Xie, Ling-Li; Yuan, Cheng-Fei; Xu, Ben-Bo

    2016-04-01

    Researchers have proven that nanomaterials have a significant effect on plant growth and development. To better understand the effects of nanomaterials on plants, Zhongshuang 11 was treated with different concentrations of graphene oxide. The results indicated that 25-100mg/l graphene oxide treatment resulted in shorter seminal root length compared with the control samples. The fresh root weight decreased when treated with 50-100mg/l graphene oxide. The graphene oxide treatment had no significant effect on the Malondialdehyde (MDA) content. Treatment with 50mg/l graphene oxide increased the transcript abundance of genes involved in ABA biosynthesis (NCED, AAO, and ZEP) and some genes involved in IAA biosynthesis (ARF2, ARF8, IAA2, and IAA3), but inhibited the transcript levels of IAA4 and IAA7. The graphene oxide treatment also resulted in a higher ABA content, but a lower IAA content compared with the control samples. The results indicated that graphene oxide modulated the root growth of Brassica napus L. and affected ABA and IAA biosynthesis and concentration. PMID:26945480

  9. 5'-azido-N-1-naphthylphthalamic acid, a photolabile analog of the auxin transport inhibitor, N-1-naphthylphthalamic acid: synthesis and binding properties

    SciTech Connect

    Voet, J.G.; Howley, K.; Shumsky, J.S.

    1987-05-01

    The polar transport of the plant growth regulator, auxin (indole-3-acetic acid, IAAH), is thought to involve the participation of several proteins in the plasma membrane, including a specific, saturable, voltage independent H/sup +//IAA/sup -/ efflux carrier located preferentially at the basal end of each cell. Auxin transport is specifically inhibited by the herbicide, N-1-naphthylphthalamic acid (NPA), which binds specifically to a protein in the plasma membrane, thought to be either the IAA/sup -/ efflux carrier or an allosteric effector protein. They have synthesized and characterized a photolabile analog of NPA, 5'-azido-N-1-naphthylphthalamic acid (Az-NPA). This potential photoaffinity label for the NPA binding protein competes with /sup 3/H-NPA for binding sites on Curcurbita pepo L. (zucchini) stem cell membranes with K/sub j/ = 1.5 x 10/sup -7/ M. The K/sub i/ for NPA under these conditions is 2 x 10/sup -8/M, indicating that the affinity of Az-NPA for the membranes is only 7.5 fold lower than NPA. While the binding of 4.6 x 10/sup -6/ M Az-NPA to NPA binding sites is reversible in the dark, exposure to light results in a 30% loss in /sup 3/H-NPA binding ability. Pretreatment with 10/sup -4/ M NPA protects the membranes against photodestruction of /sup 3/H-NPA binding sites by Az-NPA, supporting the conclusion that Az-NPA destroys these sites by specific covalent attachment.

  10. Dual Regulation Role of GH3.5 in Salicylic Acid and Auxin Signaling during Arabidopsis-Pseudomonas syringae Interaction1[W][OA

    PubMed Central

    Zhang, Zhongqin; Li, Qun; Li, Zhimiao; Staswick, Paul E.; Wang, Muyang; Zhu, Ying; He, Zuhua

    2007-01-01

    Salicylic acid (SA) plays a central role in plant disease resistance, and emerging evidence indicates that auxin, an essential plant hormone in regulating plant growth and development, is involved in plant disease susceptibility. GH3.5, a member of the GH3 family of early auxin-responsive genes in Arabidopsis (Arabidopsis thaliana), encodes a protein possessing in vitro adenylation activity on both indole-3-acetic acid (IAA) and SA. Here, we show that GH3.5 acts as a bifunctional modulator in both SA and auxin signaling during pathogen infection. Overexpression of the GH3.5 gene in an activation-tagged mutant gh3.5-1D led to elevated accumulation of SA and increased expression of PR-1 in local and systemic tissues in response to avirulent pathogens. In contrast, two T-DNA insertional mutations of GH3.5 partially compromised the systemic acquired resistance associated with diminished PR-1 expression in systemic tissues. The gh3.5-1D mutant also accumulated high levels of free IAA after pathogen infection and impaired different resistance-gene-mediated resistance, which was also observed in the GH3.6 activation-tagged mutant dfl1-D that impacted the auxin pathway, indicating an important role of GH3.5/GH3.6 in disease susceptibility. Furthermore, microarray analysis showed that the SA and auxin pathways were simultaneously augmented in gh3.5-1D after infection with an avirulent pathogen. The SA pathway was amplified by GH3.5 through inducing SA-responsive genes and basal defense components, whereas the auxin pathway was derepressed through up-regulating IAA biosynthesis and down-regulating auxin repressor genes. Taken together, our data reveal novel regulatory functions of GH3.5 in the plant-pathogen interaction. PMID:17704230

  11. Hydrogen bonding in phytohormone-auxin (IAA) and its derivatives

    NASA Astrophysics Data System (ADS)

    Kojić-Prodić, Biserka; Kroon, Jan; Puntarec, Vitomir

    1994-06-01

    The significant importance of hydrogen bonds in biological structures and enzymatic reactions has been demonstrated in many examples. As a part of the molecular recognition study of auxins (plant growth hormones) the influence of hydrogen bonding on molecular conformation, particularly of the carboxyl group, which is one of the biologically active ligand sites, has been studied by X-ray diffraction and computational chemistry methods. The survey includes about 40 crystal structures of free auxins such as indol-3-ylacetic acid and its n-alkylated and halogenated derivatives but also bound auxins such as N-(indol-3-ylacetyl)- L-amino acids, and carbohydrate conjugates. The study includes hydrogen bonds of the NH⋯O and OH⋯O types. The classification of hydrogen bond patterns based on the discrimination between the centrosymmetric and non-centrosymmetric space groups and several examples of hydrogen bond systematics on graph set analysis are also shown.

  12. Origin and basipetal transport of the IAA responsible for rooting of carnation cuttings.

    PubMed

    Garrido, Germán; Ramón Guerrero, Juan; Angel Cano, Emilio; Acosta, Manuel; Sánchez-Bravo, José

    2002-02-01

    The origin and transport of the IAA responsible for rooting was studied in carnation (Dianthus caryophyllus L.) cuttings obtained from secondary shoots of the mother plants. The presence of mature leaves in the cuttings was essential for rooting. Removal of the apex and/or the youngest leaves did not reduce the rooting percentage as long as mature leaves remained attached. Removal of mature leaves inhibited rooting for a 24-day period during which the basal leaves grew and reached maturity. After this period rooting progressed as in intact cuttings. Auxin (NAA + IBA) applied to the stem base of defoliated cuttings was about 60% as effective as mature leaves in stimulating rooting. Application of NPA to the basal internode resulted in full inhibition of rooting. The view, deduced from these results, that auxin from mature leaves is the main factor controlling the rooting process was reinforced by the fact that mature leaves contained IAA and exported labelled IAA to the stem. The distribution of radioactivity after application of (5-3H)-IAA to mature leaves showed that auxin movement in the stem was basipetal and sensitive to NPA inhibition. The features of this transport were studied by applying 3H-IAA to the apical cut surface of stem sections excised from cuttings. The intensity of the transport was lower in the oldest node than in the basal internode, probably due to the presence of vascular traces of leaves. Irrespective of the localization of the sections and the carnation cultivar used, basipetal IAA transport was severely reduced when the temperature was lowered from 25 to 4 degrees C. The polar nature of the IAA transport in the sections was confirmed by the inhibition produced by NPA. Local application of IAA to different tissues of the sections revealed that polar auxin transport was associated with the vascular cylinder, the transport in the pith and cortex being low and apolar. The present results strongly support the conclusion that IAA originating

  13. Localization of IAA transporting tissue by tissue printing and autoradiography. [Coleus; maize

    SciTech Connect

    Mee-Rye Cha; Evans, M.L.; Hangarter, R.P. )

    1991-05-01

    Tissue printing on nitrocellulose membranes provides a useful technique for visualizing anatomical details of tissue morphology of cut ends of stem segments. Basal ends of Coleus stem and corn coleoptile segments that were transporting {sup 14}C-IAA were gently blotted onto DEAE-nitrocellulose for several minutes to allow {sup 14}C-IAA to efflux from the tissue. Because of the anion exchange properties of DEAE-nitrocellulose the {sup 14}C-IAA remains on the membrane at the point it leaves the transporting tissue. Autoradiography of the DEAE membrane allowed indirect visualization of the tissues preferentially involved in auxin transport. The authors observed that polar transport through the stem segments occurred primarily through or in association with vascular tissues. However, in Coleus stems, substantial amounts of the label appeared to move through the tissue by diffusion as well as by active transport.

  14. Synthesis and characterization of ( sup 3 H)-5 prime azido-N-1-naphthylphthlamic acid, a photolabile N-1-naphthylphthalamic acid analog

    SciTech Connect

    Voet, J.G.; Dodge, B.; Harris, K.; Jacobs, M.; Larkin, L.; Bader, S.; Schnitzler, G.; Sutherland, J. )

    1990-05-01

    The NPA (N-1-naphthylphthalamic acid) receptor is an important protein involved in the regulation of transport of indole-3-acetic acid (IAA). In our attempt to isolate and characterize this protein we have previously synthesized and characterized a photolabile analog of NPA, 5{prime}-azido-NPA (Az-NPA) and shown it to be a competitor of NPA for binding sites on the NPA receptor as well as an inhibitor of auxin transport. We have now synthesized and characterized ({sup 3}H)-Az-NPA. The precursor, 2,3,4,5-Br-5{prime}-amino-NPA was dehydrohalogenated with tritium gas by Research Products International. The amino group was converted to an azido group and the product purified by HPLC. ({sup 3}H)-Az-NPA was found to be photolabile and to co-chromatograph with our synthetic unlabeled Az-NPA. Furthermore, the tritiated material was found to bind to zucchini hypocotyl cell membranes in a manner competitive with NPA as well as unlabeled Az-NPA. Photolysis of zucchini phase-partitioned plasma membranes in the presence of ({sup 3}H)-Az-NPA resulted in covalent association of tritium with the membranes. Much of this covalent association could be prevented by prior treatment of the membranes with excess NPA.

  15. Production of Thermostable Organic Solvent Tolerant Keratinolytic Protease from Thermoactinomyces sp. RM4: IAA Production and Plant Growth Promotion

    PubMed Central

    Verma, Amit; Singh, Hukum; Anwar, Mohammad S.; Kumar, Shailendra; Ansari, Mohammad W.; Agrawal, Sanjeev

    2016-01-01

    There are several reports about the optimization of protease production, but only few have optimized the production of organic solvent tolerant keratinolytic proteases that show remarkable exploitation in the development of the non-polluting processes in biotechnological industries. The present study was carried with aim to optimize the production of a thermostable organic solvent tolerant keratinolytic protease Thermoactinomyces sp. RM4 utilizing chicken feathers. Thermoactinomyces sp. RM4 isolated from the soil sample collected from a rice mill wasteyard site near Kashipur, Uttrakhand was identified on the basis of 16S rDNA analysis. The production of organic solvent tolerant keratinolytic protease enzyme by Thermoactinomyces sp. RM4 was optimized by varying physical culture conditions such as pH (10.0), temperature (60°C), inoculum percentage (2%), feather concentration (2%) and agitation rate (2 g) for feather degradation. The result showed that Thermoactinomyces sp. RM4 potentially produces extra-cellular thermostable organic solvent tolerant keratinolytic protease in the culture medium. Further, the feather hydrolysate from keratinase production media showed plant growth promoting activity by producing indole-3-acetic acid itself. The present findings suggest that keratinolytic protease from Thermoactinomyces sp. RM4 offers enormous industrial applications due to its organic solvent tolerant property in peptide synthesis, practical role in feather degradation and potential function in plant growth promoting activity, which might be a superior candidate to keep ecosystem healthy and functional. PMID:27555836

  16. Production of Thermostable Organic Solvent Tolerant Keratinolytic Protease from Thermoactinomyces sp. RM4: IAA Production and Plant Growth Promotion.

    PubMed

    Verma, Amit; Singh, Hukum; Anwar, Mohammad S; Kumar, Shailendra; Ansari, Mohammad W; Agrawal, Sanjeev

    2016-01-01

    There are several reports about the optimization of protease production, but only few have optimized the production of organic solvent tolerant keratinolytic proteases that show remarkable exploitation in the development of the non-polluting processes in biotechnological industries. The present study was carried with aim to optimize the production of a thermostable organic solvent tolerant keratinolytic protease Thermoactinomyces sp. RM4 utilizing chicken feathers. Thermoactinomyces sp. RM4 isolated from the soil sample collected from a rice mill wasteyard site near Kashipur, Uttrakhand was identified on the basis of 16S rDNA analysis. The production of organic solvent tolerant keratinolytic protease enzyme by Thermoactinomyces sp. RM4 was optimized by varying physical culture conditions such as pH (10.0), temperature (60°C), inoculum percentage (2%), feather concentration (2%) and agitation rate (2 g) for feather degradation. The result showed that Thermoactinomyces sp. RM4 potentially produces extra-cellular thermostable organic solvent tolerant keratinolytic protease in the culture medium. Further, the feather hydrolysate from keratinase production media showed plant growth promoting activity by producing indole-3-acetic acid itself. The present findings suggest that keratinolytic protease from Thermoactinomyces sp. RM4 offers enormous industrial applications due to its organic solvent tolerant property in peptide synthesis, practical role in feather degradation and potential function in plant growth promoting activity, which might be a superior candidate to keep ecosystem healthy and functional. PMID:27555836

  17. Synthesis, Crystal Structure and Biological Activity of 2-Hydroxyethylammonium Salt of p-Aminobenzoic Acid

    PubMed Central

    Crisan, Manuela E.; Bourosh, Paulina; Maffei, Massimo E.; Forni, Alessandra; Pieraccini, Stefano; Sironi, Maurizio; Chumakov, Yurii M.

    2014-01-01

    p-Aminobenzoic acid (pABA) plays important roles in a wide variety of metabolic processes. Herein we report the synthesis, theoretical calculations, crystallographic investigation, and in vitro determination of the biological activity and phytotoxicity of the pABA salt, 2-hydroxyethylammonium p-aminobenzoate (HEA-pABA). The ability of neutral and anionic forms of pABA to interact with TIR1 pocket was investigated by calculation of molecular electrostatic potential maps on the accessible surface area, docking experiments, Molecular Dynamics and Quantum Mechanics/Molecular Mechanics calculations. The docking study of the folate precursor pABA, its anionic form and natural auxin (indole-3-acetic acid, IAA) with the auxin receptor TIR1 revealed a similar binding mode in the active site. The phytotoxic evaluation of HEA-pABA, pABA and 2-hydroxyethylamine (HEA) was performed on the model plant Arabidopsis thaliana ecotype Col 0 at five different concentrations. HEA-pABA and pABA acted as potential auxin-like regulators of root development in Arabidopsis thaliana (0.1 and 0.2 mM) and displayed an agravitropic root response at high concentration (2 mM). This study suggests that HEA-pABA and pABA might be considered as potential new regulators of plant growth. PMID:25054237

  18. Synthesis, crystal structure and biological activity of 2-hydroxyethylammonium salt of p-aminobenzoic acid.

    PubMed

    Crisan, Manuela E; Bourosh, Paulina; Maffei, Massimo E; Forni, Alessandra; Pieraccini, Stefano; Sironi, Maurizio; Chumakov, Yurii M

    2014-01-01

    p-Aminobenzoic acid (pABA) plays important roles in a wide variety of metabolic processes. Herein we report the synthesis, theoretical calculations, crystallographic investigation, and in vitro determination of the biological activity and phytotoxicity of the pABA salt, 2-hydroxyethylammonium p-aminobenzoate (HEA-pABA). The ability of neutral and anionic forms of pABA to interact with TIR1 pocket was investigated by calculation of molecular electrostatic potential maps on the accessible surface area, docking experiments, Molecular Dynamics and Quantum Mechanics/Molecular Mechanics calculations. The docking study of the folate precursor pABA, its anionic form and natural auxin (indole-3-acetic acid, IAA) with the auxin receptor TIR1 revealed a similar binding mode in the active site. The phytotoxic evaluation of HEA-pABA, pABA and 2-hydroxyethylamine (HEA) was performed on the model plant Arabidopsis thaliana ecotype Col 0 at five different concentrations. HEA-pABA and pABA acted as potential auxin-like regulators of root development in Arabidopsis thaliana (0.1 and 0.2 mM) and displayed an agravitropic root response at high concentration (2 mM). This study suggests that HEA-pABA and pABA might be considered as potential new regulators of plant growth. PMID:25054237

  19. Superiority of radiobinding assay over ELISA for detection of IAAs in newly diagnosed type I diabetic children

    SciTech Connect

    Levy-Marchal, C.; Bridel, M.P.; Sodoyez-Goffaux, F.; Koch, M.; Tichet, J.; Czernichow, P.; Sodoyez, J.C. )

    1991-01-01

    Liquid- or solid-phase assays have been used for insulin autoantibody (IAA) determination, and the method of IAA measurement has not been standardized. IAAs were determined by radiobinding assay (RBA) and enzyme-linked immunosorbent assay (ELISA) in two large age-matched groups of nondiabetic and newly diagnosed insulin-dependent (type I) diabetic children. Positivity for IAA by RBA (greater than or equal to nondiabetic mean + 3SD) was 2 of 178 (1.1%) and 55 of 173 (32%) in nondiabetic and diabetic children, respectively. Prevalence of IAA by RBA was significantly higher in the youngest age-group (63% between 0-4 yr). Positivity for IAA by ELISA was 1 of 178 (0.6%) and 8 of 169 (4.7%) in nondiabetic and diabetic children, respectively. Concordance rates between both assays were 0 of 3 (0%) in control subjects and 5 of 58 (8.6%) in diabetic children. We conclude that RBA is more appropriate than ELISA for IAA detection at the onset of the disease. In addition, because available data suggest that IAAs detected by RBA only are high-affinity antibodies, it is tempting to speculate that IAAs reflect a mature immune reaction against endogenous insulin.

  20. Light-dependent gravitropism and negative phototropism of inflorescence stems in a dominant Aux/IAA mutant of Arabidopsis thaliana, axr2.

    PubMed

    Sato, Atsuko; Sasaki, Shu; Matsuzaki, Jun; Yamamoto, Kotaro T

    2014-09-01

    Gravitropism and phototropism of the primary inflorescence stems were examined in a dominant Aux/IAA mutant of Arabidopsis, axr2/iaa7, which did not display either tropism in hypocotyls. axr2-1 stems completely lacked gravitropism in the dark but slowly regained it in light condition. Though wild-type stems showed positive phototropism, axr2 stems displayed negative phototropism with essentially the same light fluence-response curve as the wild type (WT). Application of 1-naphthaleneacetic acid-containing lanolin to the stem tips enhanced the positive phototropism of WT, and reduced the negative phototropism of axr2. Decapitation of stems caused a small negative phototropism in WT, but did not affect the negative phototropism of axr2. p-glycoprotein 1 (pgp1) pgp19 double mutants showed no phototropism, while decapitated double mutants exhibited negative phototropism. Expression of auxin-responsive IAA14/SLR, IAA19/MSG2 and SAUR50 genes was reduced in axr2 and pgp1 pgp19 stems relative to that of WT. These suggest that the phototropic response of stem is proportional to the auxin supply from the shoot apex, and that negative phototropism may be a basal response to unilateral blue-light irradiation when the levels of auxin or auxin signaling are reduced to the minimal level in the primary stems. In contrast, all of these treatments reduced or did not affect gravitropism in wild-type or axr2 stems. Tropic responses of the transgenic lines that expressed axr2-1 protein by the endodermis-specific promoter suggest that AXR2-dependent auxin response in the endodermis plays a more crucial role in gravitropism than in phototropism in stems but no significant roles in either tropism in hypocotyls. PMID:24938853

  1. 2,4-D and IAA Amino Acid Conjugates Show Distinct Metabolism in Arabidopsis

    PubMed Central

    Eyer, Luděk; Vain, Thomas; Pařízková, Barbora; Oklestkova, Jana; Barbez, Elke; Kozubíková, Hana; Pospíšil, Tomáš; Wierzbicka, Roksana; Kleine-Vehn, Jürgen; Fránek, Milan; Strnad, Miroslav; Robert, Stéphanie

    2016-01-01

    The herbicide 2,4-D exhibits an auxinic activity and therefore can be used as a synthetic and traceable analog to study auxin-related responses. Here we identified that not only exogenous 2,4-D but also its amide-linked metabolite 2,4-D-Glu displayed an inhibitory effect on plant growth via the TIR1/AFB auxin-mediated signaling pathway. To further investigate 2,4-D metabolite conversion, identity and activity, we have developed a novel purification procedure based on the combination of ion exchange and immuno-specific sorbents combined with a sensitive liquid chromatography-mass spectrometry method. In 2,4-D treated samples, 2,4-D-Glu and 2,4-D-Asp were detected at 100-fold lower concentrations compared to 2,4-D levels, showing that 2,4-D can be metabolized in the plant. Moreover, 2,4-D-Asp and 2,4-D-Glu were identified as reversible forms of 2,4-D homeostasis that can be converted to free 2,4-D. This work paves the way to new studies of auxin action in plant development. PMID:27434212

  2. Status of the IAA study group on traffic management rules for space operations

    NASA Astrophysics Data System (ADS)

    Contant, Corinne; Lala, Petr; Schrogl, Kai-Uwe

    2007-10-01

    The investigation of space traffic and its management has only recently become a point of wider discussion. In particular, the series of workshops organized by the American Institute of Aeronautics and Astronautics (AIAA) and other international organizations on international cooperation highlighted the issue. It was discussed thoroughly at the workshops, which took place in 1999 and 2001, respectively. It was at the 2001 workshop, when the suggestion was made that an International Academy of Astronautics (IAA) Study on the subject of space traffic management should be prepared. This suggestion was taken up and a proposal was presented to the Board of Trustees of IAA, which, in late 2001, accepted this proposal. Following this, an interdisciplinary study group of around 20 persons was composed. One early milestone in the process of work was the conduct of an International Institute of Space Law (IISL)/European Center of Space Law (ECSL) Symposium alongside the 2002 session of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) Legal Subcommittee. This symposium consisted of presentations of members of the IAA study group. Also, close coordination with other study projects of IAA, in particular with the one on space debris, is sought. This paper presents the status of work of the study group, in particular, the approach and the scope of the study as well as its preliminary findings. The study group intends to finalize its work in early 2004, in order to be able to put the study before IAA and launch its review process before the 2004 International Astronautical Congress. Following this review, the study will be published and may be expected to make an impact in fora like the UNCOPUOS. The authors of this paper act as the coordinators/the rapporteur to this study. The paper will be presented in the IAA—as well as the IISL—session dealing with space traffic, by that bridging the two areas and seeking input from various sources.

  3. Strawberry Fruit Protein With a Novel Post-Translational Indole-acyl Modification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit of the diploid strawberry, Fragaria vesca, L. ‘Yellow Wonder’ contain indole-3-acetic acid (IAA) covalently attached to specific strawberry proteins. Protein-conjugated IAA accounts for between 0.4 and 4 ng of IAA per gram fresh weight of tissue in achenes, and in receptacle tissue. Immunob...

  4. Auxin Chemical and Molecular Biology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Auxins function as key regulators at the intersection between developmental and environmental events and the response pathways that they trigger. Naturally occurring members of this hormone group include indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and 4-chloro-indole-3-acetic acid (4-Cl...

  5. Oxidative Stress Induced by Pt(IV) Pro-drugs Based on the Cisplatin Scaffold and Indole Carboxylic Acids in Axial Position

    PubMed Central

    Tolan, Dina; Gandin, Valentina; Morrison, Liam; El-Nahas, Ahmed; Marzano, Cristina; Montagner, Diego; Erxleben, Andrea

    2016-01-01

    The use of Pt(IV) complexes as pro-drugs that are activated by intracellular reduction is a widely investigated approach to overcome the limitations of Pt(II) anticancer agents. A series of ten mono- and bis-carboxylated Pt(IV) complexes with axial indole-3-acetic acid (IAA) and indole-3-propionic acid (IPA) ligands were synthesized and characterized by elemental analysis, ESI-MS, FT-IR, 1H and 195Pt NMR spectroscopy. Cellular uptake, DNA platination and cytotoxicity against a panel of human tumor cell lines were evaluated. All the complexes are able to overcome cisplatin-resistance and the most potent complex, cis,cis,trans-[Pt(NH3)2Cl2(IPA)(OH)] was on average three times more active than cisplatin. Mechanistic studies revealed that the trend in cytotoxicity of the Pt(IV) complexes is primarily consistent with their ability to accumulate into cancer cells and to increase intracellular basal reactive oxygen species levels, which in turn results in the loss of mitochondrial membrane potential and apoptosis induction. The role of the indole acid ligand as a redox modulator is discussed. PMID:27404565

  6. Oxidative Stress Induced by Pt(IV) Pro-drugs Based on the Cisplatin Scaffold and Indole Carboxylic Acids in Axial Position

    NASA Astrophysics Data System (ADS)

    Tolan, Dina; Gandin, Valentina; Morrison, Liam; El-Nahas, Ahmed; Marzano, Cristina; Montagner, Diego; Erxleben, Andrea

    2016-07-01

    The use of Pt(IV) complexes as pro-drugs that are activated by intracellular reduction is a widely investigated approach to overcome the limitations of Pt(II) anticancer agents. A series of ten mono- and bis-carboxylated Pt(IV) complexes with axial indole-3-acetic acid (IAA) and indole-3-propionic acid (IPA) ligands were synthesized and characterized by elemental analysis, ESI-MS, FT-IR, 1H and 195Pt NMR spectroscopy. Cellular uptake, DNA platination and cytotoxicity against a panel of human tumor cell lines were evaluated. All the complexes are able to overcome cisplatin-resistance and the most potent complex, cis,cis,trans-[Pt(NH3)2Cl2(IPA)(OH)] was on average three times more active than cisplatin. Mechanistic studies revealed that the trend in cytotoxicity of the Pt(IV) complexes is primarily consistent with their ability to accumulate into cancer cells and to increase intracellular basal reactive oxygen species levels, which in turn results in the loss of mitochondrial membrane potential and apoptosis induction. The role of the indole acid ligand as a redox modulator is discussed.

  7. Defining Binding Efficiency and Specificity of Auxins for SCFTIR1/AFB-Aux/IAA Co-receptor Complex Formation

    PubMed Central

    2013-01-01

    Structure–activity profiles for the phytohormone auxin have been collected for over 70 years, and a number of synthetic auxins are used in agriculture. Auxin classification schemes and binding models followed from understanding auxin structures. However, all of the data came from whole plant bioassays, meaning the output was the integral of many different processes. The discovery of Transport Inhibitor-Response 1 (TIR1) and the Auxin F-Box (AFB) proteins as sites of auxin perception and the role of auxin as molecular glue in the assembly of co-receptor complexes has allowed the development of a definitive quantitative structure–activity relationship for TIR1 and AFB5. Factorial analysis of binding activities offered two uncorrelated factors associated with binding efficiency and binding selectivity. The six maximum-likelihood estimators of Efficiency are changes in the overlap matrixes, inferring that Efficiency is related to the volume of the electronic system. Using the subset of compounds that bound strongly, chemometric analyses based on quantum chemical calculations and similarity and self-similarity indices yielded three classes of Specificity that relate to differential binding. Specificity may not be defined by any one specific atom or position and is influenced by coulomb matrixes, suggesting that it is driven by electrostatic forces. These analyses give the first receptor-specific classification of auxins and indicate that AFB5 is the preferred site for a number of auxinic herbicides by allowing interactions with analogues having van der Waals surfaces larger than that of indole-3-acetic acid. The quality factors are also examined in terms of long-standing models for the mechanism of auxin binding. PMID:24313839

  8. Aboveground Whitefly Infestation Modulates Transcriptional Levels of Anthocyanin Biosynthesis and Jasmonic Acid Signaling-Related Genes and Augments the Cope with Drought Stress of Maize

    PubMed Central

    Park, Yong-Soon; Bae, Dong-Won; Ryu, Choong-Min

    2015-01-01

    Up to now, the potential underlying molecular mechanisms by which maize (Zea mays L.) plants elicit defense responses by infestation with a phloem feeding insect whitefly [Bemisia tabaci (Genn.)] have been barely elucidated against (a)biotic stresses. To fill this gap of current knowledge maize plants were infested with whitefly and these plants were subsequently assessed the levels of water loss. To understand the mode of action, plant hormone contents and the stress-related mRNA expression were evaluated. Whitefly-infested maize plants did not display any significant phenotypic differences in above-ground tissues (infested site) compared with controls. By contrast, root (systemic tissue) biomass was increased by 2-fold by whitefly infestation. The levels of endogenous indole-3-acetic acid (IAA), jasmonic acid (JA), and hydrogen peroxide (H2O2) were significantly higher in whitefly-infested plants. The biosynthetic or signaling-related genes for JA and anthocyanins were highly up-regulated. Additionally, we found that healthier plants were obtained in whitefly-infested plants under drought conditions. The weight of whitefly-infested plants was approximately 20% higher than that of control plants at 14 d of drought treatment. The drought tolerance-related genes, ZmbZIP72, ZmSNAC1, and ZmABA1, were highly expressed in the whitefly-infected plants. Collectively, our results suggest that IAA/JA-derived maize physiological changes and correlation of H2O2 production and water loss are modulated by above-ground whitefly infestation in maize plants. PMID:26630288

  9. Aboveground Whitefly Infestation Modulates Transcriptional Levels of Anthocyanin Biosynthesis and Jasmonic Acid Signaling-Related Genes and Augments the Cope with Drought Stress of Maize.

    PubMed

    Park, Yong-Soon; Bae, Dong-Won; Ryu, Choong-Min

    2015-01-01

    Up to now, the potential underlying molecular mechanisms by which maize (Zea mays L.) plants elicit defense responses by infestation with a phloem feeding insect whitefly [Bemisia tabaci (Genn.)] have been barely elucidated against (a)biotic stresses. To fill this gap of current knowledge maize plants were infested with whitefly and these plants were subsequently assessed the levels of water loss. To understand the mode of action, plant hormone contents and the stress-related mRNA expression were evaluated. Whitefly-infested maize plants did not display any significant phenotypic differences in above-ground tissues (infested site) compared with controls. By contrast, root (systemic tissue) biomass was increased by 2-fold by whitefly infestation. The levels of endogenous indole-3-acetic acid (IAA), jasmonic acid (JA), and hydrogen peroxide (H2O2) were significantly higher in whitefly-infested plants. The biosynthetic or signaling-related genes for JA and anthocyanins were highly up-regulated. Additionally, we found that healthier plants were obtained in whitefly-infested plants under drought conditions. The weight of whitefly-infested plants was approximately 20% higher than that of control plants at 14 d of drought treatment. The drought tolerance-related genes, ZmbZIP72, ZmSNAC1, and ZmABA1, were highly expressed in the whitefly-infected plants. Collectively, our results suggest that IAA/JA-derived maize physiological changes and correlation of H2O2 production and water loss are modulated by above-ground whitefly infestation in maize plants. PMID:26630288

  10. Influence of age and composition of shelterbelts plants on enzyme activity and auxine - phytophormone IAA concentrations in soils

    NASA Astrophysics Data System (ADS)

    Wojciech Szajdak, Lech; Gaca, Wioletta; Meysner, Teresa; Styła, Katarzyna; Maryganova, Victoria

    2010-05-01

    The investigations were carried out in Dezydery Chlapowski Agroecological Landscape Park in Turew (40 km South-West of Poznań, West Polish Lowlands, 16° 45 E and 52° 01 N). The soil samples were taken from two shelterbelts differing the age and the composition of trees. First 200-years-old shelterbelt is consisting mainly by Robinia pseudacacia and small admixture of Quercus robur and Larix deciduas. It has 2 kilometers of length and 36 meters of width. The second one new shelterbelt (many species) was created in 1993 and consists of several species of plants such as: Quercus pertraea and Quercus robur, Larix decidua, Pinus silvestris, Sorbus aucuparia, Sorbus intermedia and Tilia cordata. Its length is 340 meters and its width is 17.5 meters. All shelterbelts and adjoining cultivated fields were introduced on Hapludalfs soils (according to FAO classification). In soil under two shelterbelts and adjoining cultivated fields the activity of the following enzymes nitrate reductase, urease, xanthine oxidase, phenol oxidase, peroxidase activity were measured. In addition, the concentrations of iron ions, indole-3-acetic acids, total organic carbon, dissolved organic carbon, total nitrogen, ammonium and nitrates were determined. In soils under shelterbelts compared to adjoining cultivated fields higher content of organic matter was observed, because the accumulation of soil organic matter under shelterbelts is suggested to be the main mechanism of long-term withdrawal of various chemical elements from cycling in the agroecosystems. However, many chemical, biochemical, physical and biological processes control conversions of organic compounds in soils and finally these processes depend on the organic matter content and particularly on humic substances. Due to a very good developed root system of trees in shelterbelts than cultivated plants, they transpire more than 34% water than cultivated fields and intensively take up nutrients and finally improve quality of ground

  11. Magnesium deficiency effects on IAA-1-/sup 14/C decarboxylation in Alaska and Little Marvel pea tissues

    SciTech Connect

    Henry, E.W.; Haduck, P.; Haduck, W.; Joyner, M.

    1987-04-01

    This investigation seeks to determine the effects of magnesium deficiency on light and dark exposed Alaska (normal) and Little Marvel (dwarf) pea tissue, with respect to IAA-1-/sup 14/C decarboxylation, in root, stem, and leaf tissues. There is both a higher rate of IAA-1-/sup 14/C decarboxylation and enhanced stem growth in Alaska, vs. Little Marvel pea tissue. The decarboxylation of IAA-1-/sup 14/C is highest in roots, slightly lower in leaves, followed by the proximal and distal designated stem tissues. With respect to light effects, the absence of light causes a decrease in IAA-1-/sup 14/C decarboxylation, the effect being most prominent in the leaves, with the least effect being exhibited in the root tissue. In summary, magnesium deficiency causes a decrease in IAA-1-/sup 14/C decarboxylation in both Alaska and Little Marvel pea tissues. It is suggested that the lack of available magnesium causes general physiological stress, with the plant attempting to redistribute any of the still available endogenous ion. The rate and pathway of IAA metabolism may vary significant between different types of cells in magnesium deficient tissues.

  12. IAA stimulates pollen tube growth and mediates the modification of its wall composition and structure in Torenia fournieri

    PubMed Central

    Wu, Juan-Zi; Lin, Yi; Zhang, Xue-Lian; Pang, Dai-Wen; Zhao, Jie

    2008-01-01

    The effects of several hormones on pollen tube growth were compared in Torenia fournieri and it was found that IAA was the most effective, stimulating pollen tube growth and causing the shank part of pollen tubes to be slender and straighter. The role of IAA was investigated by studying the changes in ultrastructure and PM H+-ATPase distribution in the pollen tubes and the modification of the tube wall. Using the fluorescent marker FM4-64, together with transmission electron microscopy, it was shown that secretory vesicles and mitochondria increased in IAA-treated tubes. Immunolocalization and fluorescence labelling, together with Fourier-transform infrared analysis, detected that IAA enhanced the level of PM H+-ATPase and the synthesis of pectins, and reduced the cellulose density in pollen tubes. Importantly, to observe the orientation of cellulose microfibrils in pollen tubes in situ, atomic force microscopy was used to examine the ‘intact’ tube wall. Atomic force microscopy images showed that cellulose microfibrils were parallel to each other in the subapical region of IAA-treated tubes, but disorganized in control tubes. All results provided new insights into the functions of cellulose microfibrils in pollen tube growth and direction, and revealed that the IAA-induced changes of pollen tubes were attributed to the increase in secretory vesicles, mitochondria, and PM H+-ATPase, and the modification of pectin and cellulose microfibrils in the tube wall. PMID:18544613

  13. Numerical ephemerides of planets and natural satellites of IAA RAS and their uses for scientific research

    NASA Astrophysics Data System (ADS)

    Pitjeva, E.; Kosmodamianskiy, G.; Pavlov, D.; Pitjev, N.; Poroshina, A.; Skripnichenko, V.

    2014-12-01

    The dynamical model of the planetary part of the EPM2013 ephemerides of the IAA RAS has been fitted to about 800000 observations of different types (1913-2013). Their reference frame has been established with 321 ICRF-based VLBI measurements of spacecrafts near planets taken into account. EPM ephemerides serve as the basis for the Russian Astronomical and Nautical Astronomical Yearbooks, are planned to be used in the GLONASS and LUNA-RESOURCE programs, and are used for determination of physical parameters (asteroids masses, planet rotation, topography), GM_Sun and its secular variation, the PPN parameters, the upper limit on mass of the dark matter in the Solar System. Moreover, numerical ephemerides of the 22 main planet satellites have been constructed; they also provide the basis for improving positions of the outer planets. Files containing polynomial approximation for EPM ephemerides (EPM2004, EPM2008, EPM2011) along with TT-TDB and ephemerides of Ceres, Pallas, Vesta, Eris, Haumea, Makemake, and Sedna are available from ftp://quasar.ipa.nw.ru/incoming/ EPM/. The files are provided in IAA's binary and ASCII formats, as well as SPK and PCK formats.

  14. SAR imaging in the presence of spectrum notches via fast missing data IAA

    NASA Astrophysics Data System (ADS)

    Rowe, William; Karlsson, Johan; Xu, Luzhou; Glentis, George-Othon; Li, Jian

    2013-05-01

    A synthetic aperture radar system operating in congested frequency bands suffers from radio frequency inter­ ference (RFI) from narrowband sources. When RFI interference is suppressed by frequency notching, gaps are introduced into the fast time phase history. This results in a missing data spectral estimation problem, where the missing data increases sidelobe energy and degrades image quality. The adaptive spectral estimation method Iterative Adaptive Approach (IAA) has been shown to provide higher resolution and lower sidelobes than comparable methods, but at the cost of higher computationally complexity. Current fast IAA algorithms reduce the computational complexity using Toeplitz /Vandermonde structures, but are not applicable for missing data cases because these structures are lost. When the number of missing data samples is small, which often is the case in SAR with RFI, we use a low rank completion to restore the Toeplitz/ Vandermonde structures. We show that the computational complexity of the proposed algorithm is considerably lower than the state-of-the-art and demonstrate the utility on a simulated frequency notched SAR imaging problem.

  15. WITHDRAWN: Erythrodiol-3-acetate isolated from Styrax japonica elicits the inhibition of UV-induced gelatinases B in cultured human keratinocyte cells.

    PubMed

    Moon, Hyungin; Jung, Jae-Chul

    2007-02-26

    Methanol and aqueous extracts of Styrax japonica Sieb. et Zucc used traditionally for the treatments of skin elastic materials were screened in vitro for the gelatinases B inhibitor actions. Erythrodiol-3-acetate (E) from the stem barks of S. japonica showed significant gelatinase B inhibition in human keratinocyte cells caused by ultraviolet irradiation. Here we investigated the effect of E, which was isolated from S. japonica on UV-induced premature skin aging. We studied the effect of E on UV-induced gelatinase B expression in an immortalized human keratinocyte cell line, in vitro. Acute UV irradiation induced gelatinase B expression at the protein levels and E suppressed this UV-induced gelatinase B expression in a dose-dependent manner. Taken together, these results show that E can prevent the harmful effects of UV that lead to skin aging or skin cancer. Therefore, we suggest that E should be viewed as a potential therapeutic agent for preventing and/or treating premature skin aging. PMID:17329089

  16. Transport of stele-associated IAA in gravistimulated roots of maize

    SciTech Connect

    Stinemetz, C.L.; Evans, M.L. )

    1989-04-01

    We tested the redistribution of label from a pulse of {sup 3}H IAA applied to the cut surface of 5 mm apical root segments. We determined the amount of label in the stele, meristematic region (MR), root cap, and cortical tissue on the lower and upper sides of gravistimulated vs control roots. Label entered the stele and moved into the MR prior to accumulating in the elongation zone (EZ). Little label moved into the cap. Gravistimulation did not increase the amount of label moving from the stele, but it increased the amount of label accumulating on the lower side of the EZ. Removal of the cap immediately following gravistimulation rendered the roots insensitive to gravity and prevented gravi-induced asymmetric redistribution of label. The results suggest that a signal originating in the root cap directs auxin redistribution in tissue behind the cap.

  17. EPM-ERA 2013 - The new version of lunar ephemeris developed in IAA RAS

    NASA Astrophysics Data System (ADS)

    Yagudina, E.; Vasiliev, M.

    2014-12-01

    EPM-ERA 2013 is the newest version of the lunar ephemeris developed in IAA RAS after 2011. New Lunar ephemeris EPM-ERA 2013 was compared with USA DE405, DE421, DE423, DE430 and French INPOP10e lunar ephemerides. Comparison showed that EPM-ERA 2013 is still slightly worse than all of these ephemerides, suggesting the necessity of further improving the dynamical model of EPMERA. The fact that all modern lunar ephemerides evidently cannot adequately describe most accurate LLR observations makes this task especially pressing for authors. Several practical applications were also considered to estimate the impact of the using different lunar ephemerides on the orbit determination accuracy of such objects as GNSS satellites and Near-Earth asteroids.

  18. The jasmonic acid signaling pathway is linked to auxin homeostasis through the modulation of YUCCA8 and YUCCA9 gene expression.

    PubMed

    Hentrich, Mathias; Böttcher, Christine; Düchting, Petra; Cheng, Youfa; Zhao, Yunde; Berkowitz, Oliver; Masle, Josette; Medina, Joaquín; Pollmann, Stephan

    2013-05-01

    Interactions between phytohormones play important roles in the regulation of plant growth and development, but knowledge of the networks controlling hormonal relationships, such as between oxylipins and auxins, is just emerging. Here, we report the transcriptional regulation of two Arabidopsis YUCCA genes, YUC8 and YUC9, by oxylipins. Similar to previously characterized YUCCA family members, we show that both YUC8 and YUC9 are involved in auxin biosynthesis, as demonstrated by the increased auxin contents and auxin-dependent phenotypes displayed by gain-of-function mutants as well as the significantly decreased indole-3-acetic acid (IAA) levels in yuc8 and yuc8/9 knockout lines. Gene expression data obtained by qPCR analysis and microscopic examination of promoter-reporter lines reveal an oxylipin-mediated regulation of YUC9 expression that is dependent on the COI1 signal transduction pathway. In support of these findings, the roots of the analyzed yuc knockout mutants displayed a reduced response to methyl jasmonate (MeJA). The similar response of the yuc8 and yuc9 mutants to MeJA in cotyledons and hypocotyls suggests functional overlap of YUC8 and YUC9 in aerial tissues, while their function in roots shows some specificity, probably in part related to different spatio-temporal expression patterns of the two genes. These results provide evidence for an intimate functional relationship between oxylipin signaling and auxin homeostasis. PMID:23425284

  19. The ARF, AUX/IAA and GH3 gene families in citrus: genome-wide identification and expression analysis during fruitlet drop from abscission zone A.

    PubMed

    Xie, Rangjin; Pang, Shaoping; Ma, Yanyan; Deng, Lie; He, Shaolan; Yi, Shilai; Lv, Qiang; Zheng, Yongqiang

    2015-12-01

    Completion of the whole genome sequencing of citrus enabled us to perform genome-wide identification and functional analysis of the gene families involved in agronomic traits and morphological diversity of citrus. In this study, 22 CitARF, 11 CitGH3 and 26 CitAUX/IAA genes were identified in citrus, respectively. Phylogenetic analysis revealed that all the genes of each gene family could be subdivided into three groups and showed strong evolutionary conservation. The GH3 and AUX/IAA gene families shrank and ARF gene family was highly conserved in the citrus genome after speciation from Arabidopsis thaliana. Tissue-specific expression profiles revealed that 54 genes were expressed in at least one tissue while just 5 genes including CitARF07, CitARF20, CitGH3.04, CitAUX/IAA25 and CitAUX/IAA26 with very low expression level in all tissues tested, suggesting that the CitARF, CitGH3 and CitAUX/IAA gene families played important roles in the development of citrus organs. In addition, our data found that the expression of 2 CitARF, 4 CitGH3 and 4 AUX/IAA genes was affected by IAA treatment, and 7 genes including, CitGH3.04, CitGH3.07, CitAUX/IAA03, CitAUX/IAA04, CitAUX/IAA18, CitAUX/IAA19 and CitAUX/IAA23 were related to fruitlet abscission. This study provides a foundation for future studies on elucidating the precise role of citrus ARF, GH3 and AUX/IAA genes in early steps of auxin signal transduction and open up a new opportunity to uncover the molecular mechanism underlying citrus fruitlet abscission. PMID:25982744

  20. Conserved and unique features of the homeologous maize Aux/IAA proteins ROOTLESS WITH UNDETECTABLE MERISTEM 1 and RUM1-like 1

    PubMed Central

    Zhang, Yanxiang; Marcon, Caroline; Tai, Huanhuan; von Behrens, Inga; Ludwig, Yvonne; Hey, Stefan; Berendzen, Kenneth W.; Hochholdinger, Frank

    2016-01-01

    The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1) is a key regulator of lateral and seminal root formation. An ancient maize genome duplication resulted in the emergence of its homeolog rum1-like1 (rul1), which displays 92% amino acid sequence identity with RUM1. Both, RUL1 and RUM1 exhibit the canonical four domain structure of Aux/IAA proteins. Moreover, both are localized to the nucleus, are instable and have similar short half-lives of ~23min. Moreover, RUL1 and RUM1 can be stabilized by specific mutations in the five amino acid degron sequence of domain II. In addition, proteins encoded by both genes interact in vivo with auxin response factors (ARFs) such as ZmARF25 and ZmARF34 in protoplasts. Although it was demonstrated that RUL1 and RUM1 can homo and heterodimerize in vivo, rul1 expression is independent of rum1. Moreover, on average rul1 expression is ~84-fold higher than rum1 in the 12 tested tissues and developmental stages, although the relative expression levels in different root tissues are very similar. While RUM1 and RUL1 display conserved biochemical properties, yeast-two-hybrid in combination with BiFC experiments identified a RUM1-associated protein 1 (RAP1) that specifically interacts with RUM1 but not with RUL1. This suggests that RUM1 and RUL1 are at least in part interwoven into different molecular networks. PMID:26672614

  1. Conserved and unique features of the homeologous maize Aux/IAA proteins ROOTLESS WITH UNDETECTABLE MERISTEM 1 and RUM1-like 1.

    PubMed

    Zhang, Yanxiang; Marcon, Caroline; Tai, Huanhuan; von Behrens, Inga; Ludwig, Yvonne; Hey, Stefan; Berendzen, Kenneth W; Hochholdinger, Frank

    2016-02-01

    The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1) is a key regulator of lateral and seminal root formation. An ancient maize genome duplication resulted in the emergence of its homeolog rum1-like1 (rul1), which displays 92% amino acid sequence identity with RUM1. Both, RUL1 and RUM1 exhibit the canonical four domain structure of Aux/IAA proteins. Moreover, both are localized to the nucleus, are instable and have similar short half-lives of ~23min. Moreover, RUL1 and RUM1 can be stabilized by specific mutations in the five amino acid degron sequence of domain II. In addition, proteins encoded by both genes interact in vivo with auxin response factors (ARFs) such as ZmARF25 and ZmARF34 in protoplasts. Although it was demonstrated that RUL1 and RUM1 can homo and heterodimerize in vivo, rul1 expression is independent of rum1. Moreover, on average rul1 expression is ~84-fold higher than rum1 in the 12 tested tissues and developmental stages, although the relative expression levels in different root tissues are very similar. While RUM1 and RUL1 display conserved biochemical properties, yeast-two-hybrid in combination with BiFC experiments identified a RUM1-associated protein 1 (RAP1) that specifically interacts with RUM1 but not with RUL1. This suggests that RUM1 and RUL1 are at least in part interwoven into different molecular networks. PMID:26672614

  2. Transport of sup 14 C-IAA and sup 14 C-ACC within floral organs of Ipomoea nil

    SciTech Connect

    Kiss, H.G. ); Maurice, H.R. ); Koning, R.E. ); Daie, J. )

    1989-04-01

    The transport of {sup 14}C-IAA {sup 14}C-ACC from agarose donor blocks applied to I. nil filaments their recovery as {sup 14}C-accumulation into floral organs was examined. The accumulation of the isotopes in the corolla tissue was greater when {sup 14}C-ACC was applied than {sup 14}C-IAA in intact isolated flower buds. Greater levels of the isotopes accumulated in the pistil, with minimal levels in receptacle and calyx tissues from isolated buds. With intact buds, greater levels of the isotopes were recovered in pistil, calyx receptacle tissues. This study provides further evidence for the role of the filaments as transport vectors for IAA ACC for the production of ethylene.

  3. Evidence That Chlorinated Auxin Is Restricted to the Fabaceae But Not to the Fabeae1[OPEN

    PubMed Central

    McAdam, Scott A.M.; McAdam, Erin L.

    2015-01-01

    Auxin is a pivotal plant hormone, usually occurring in the form of indole-3-acetic acid (IAA). However, in maturing pea (Pisum sativum) seeds, the level of the chlorinated auxin, 4-chloroindole-3-acetic acid (4-Cl-IAA), greatly exceeds that of IAA. A key issue is how plants produce halogenated compounds such as 4-Cl-IAA. To better understand this topic, we investigated the distribution of the chlorinated auxin. We show for the first time, to our knowledge, that 4-Cl-IAA is found in the seeds of Medicago truncatula, Melilotus indicus, and three species of Trifolium. Furthermore, we found no evidence that Pinus spp. synthesize 4-Cl-IAA in seeds, contrary to a previous report. The evidence indicates a single evolutionary origin of 4-Cl-IAA synthesis in the Fabaceae, which may provide an ideal model system to further investigate the action and activity of halogenating enzymes in plants. PMID:25971549

  4. Evidence That Chlorinated Auxin Is Restricted to the Fabaceae But Not to the Fabeae.

    PubMed

    Lam, Hong Kiat; McAdam, Scott A M; McAdam, Erin L; Ross, John J

    2015-07-01

    Auxin is a pivotal plant hormone, usually occurring in the form of indole-3-acetic acid (IAA). However, in maturing pea (Pisum sativum) seeds, the level of the chlorinated auxin, 4-chloroindole-3-acetic acid (4-Cl-IAA), greatly exceeds that of IAA. A key issue is how plants produce halogenated compounds such as 4-Cl-IAA. To better understand this topic, we investigated the distribution of the chlorinated auxin. We show for the first time, to our knowledge, that 4-Cl-IAA is found in the seeds of Medicago truncatula, Melilotus indicus, and three species of Trifolium. Furthermore, we found no evidence that Pinus spp. synthesize 4-Cl-IAA in seeds, contrary to a previous report. The evidence indicates a single evolutionary origin of 4-Cl-IAA synthesis in the Fabaceae, which may provide an ideal model system to further investigate the action and activity of halogenating enzymes in plants. PMID:25971549

  5. Space Weather Research at IAA/NOA: Solar Energetic Particle Investigations

    NASA Astrophysics Data System (ADS)

    Malandraki, O.; Tylka, A. J.; Ng, C. K.; Marsden, R. G.; Tranquille, C.; Klein, K. L.; Patterson, J. D.; Armstrong, T. P.; Lanzerotti, L. J.; Papaioannou, A.; Marhavilas, P. K.; Tziotziou, K.; Crosby, N.; Vainio, R.

    2012-01-01

    During an eleven year cycle the Sun goes from quiet conditions at minimum to levels of high activity at maximum. In the latter case, energetic phenomena such as coronal mass ejections (CMEs) and solar flares (SFs) accompanied by explosive releases of mass, magnetic flux and solar energetic particles (SEPs) are common. Damaging effects, as a result of these phenomena, have been recorded on satellites, on-board detectors and in extreme cases on ground based systems (e.g. oil and natural gas pipelines, communication systems, aircraft electronics, power-grids). Furthermore, the intense SEP radiation can damage human DNA and cause cell replications. To this end, ensuring the safety of astronauts working in the extreme conditions of space, especially the energetic particle environments, is a key goal for both ESA and NASA. The analysis, the risk assessment and management and the possible forecasting of such events constitutes the scientific field of Space Weather. The Institute of Astronomy and Astrophysics (IAA) of the National Observatory of Athens (NOA) is currently strongly involved in two collaborative projects funded by the seventh framework program of the European Union, namely: 'SEPServer' and 'COMESEP'. 'SEPServer' focuses on the implementation of a comprehensive and up to date SEP analysis service including scientific data driven analysis both for 1 AU and for > 1 AU using data from the SOHO/ ERNE, SOHO/EPHIN, ACE/EPAM, ACE/SIS, WIND/3DP, Ulysses/HISCALE, Ulysses/COSPIN/LET and Ulysses/COSPIN/KET experiments. SEPServer will also provide for the first time the release of the HELIOS data set in a reasonable format and in full time resolution, thus making available data also for orbits inside 1 AU (down to 0.3 AU). Observational data-driven analysis methods such as: onset determination, velocity dispersion, and/or time-shifting analysis, direct comparison of observed SEP fluxes, spectra and abundance ratios with the associated electromagnetic emission data will be

  6. Two-dimensional solar spectropolarimetry with the KIS/IAA Visible Imaging Polarimeter

    NASA Astrophysics Data System (ADS)

    Beck, C.; Bellot Rubio, L. R.; Kentischer, T. J.; Tritschler, A.; Del Toro Iniesta, J. C.

    2010-09-01

    Context. Spectropolarimetry at high spatial and spectral resolution is a basic tool to characterize the magnetic properties of the solar atmosphere. Aims: We introduce the KIS/IAA Visible Imaging Polarimeter (VIP), a new post-focus instrument that upgrades the TESOS spectrometer at the German Vacuum Tower Telescope (VTT) into a full vector polarimeter. VIP is a collaboration between the Kiepenheuer Institut für Sonnenphysik (KIS) and the Instituto de Astrofísica de Andalucía (IAA-CSIC). Methods: We describe the optical setup of VIP, the data acquisition procedure, and the calibration of the spectropolarimetric measurements. We show examples of data taken between 2005 and 2008 to illustrate the potential of the instrument. Results: VIP is capable of measuring the four Stokes profiles of spectral lines in the range from 420 to 700 nm with a spatial resolution better than 0farcs5. Lines can be sampled at 40 wavelength positions in 60 s, achieving a noise level of about 2 × 10-3 with exposure times of 300 ms and pixel sizes of 0farcs17 × 0farcs17 (2 × 2 binning). The polarization modulation is stable over periods of a few days, ensuring high polarimetric accuracy. The excellent spectral resolution of TESOS allows the use of sophisticated data analysis techniques such as Stokes inversions. One of the first scientific results of VIP presented here is that the ribbon-like magnetic structures of the network are associated with a distinct pattern of net circular polarization away from disk center. Conclusions: VIP performs spectropolarimetric measurements of solar magnetic fields at a spatial resolution that is only slightly worse than that of the Hinode spectropolarimeter, while providing a 2D field field of view and the possibility to observe up to four spectral regions sequentially with high cadence. VIP can be used as a stand-alone instrument or in combination with other spectropolarimeters and imaging systems of the VTT for extended wavelength coverage.

  7. A genetic screen for mutants defective in IAA1-LUC degradation in Arabidopsis thaliana reveals an important requirement for TOPOISOMERASE6B in auxin physiology

    PubMed Central

    Gilkerson, Jonathan; Callis, Judy

    2014-01-01

    Many plant growth and developmental processes are modulated by the hormone auxin. Auxin-modulated proteolysis of Aux/IAAs, a family of transcriptional repressors, represents a major mode of auxin action. Auxin facilitates the interaction of Aux/IAAs with TIR1/AFB F-box proteins, promoting their ubiquitination by the SCFTIR1/AFB ubiquitin E3 ligase leading to subsequent degradation by the 26S proteasome. To identify new genes regulating Aux/IAA proteolysis in Arabidopsis thaliana, we took a genetic approach, identifying individuals with altered degradation of an IAA1-luciferase fusion protein (IAA1-LUC). A mutant with 2-fold slower IAA1-LUC degradation rate compared with wild-type was isolated. Positional cloning identified the mutant as an allele of TOPOISOMERASE6B, named top6b-7. TOP6B encodes a subunit of a plant and archea-specific enzyme regulating endoreduplication, DNA damage repair and transcription in plants. T-DNA insertion alleles (top6b-8 and top6b-9) were also analyzed. top6b-7 seedlings are less sensitive to exogenous auxin than wild-type siblings in primary root growth assays, and experiments with DR5:GUS. Additionally, top6b-7 seedlings have a 40% reduction in the amount of endogenous IAA. These data suggest that increased IAA1-LUC half-life in top6b-7 probably results from a combination of both lower endogenous IAA levels and reduced sensitivity to auxin. PMID:25482814

  8. Early Fuel Cell Market Deployments: ARRA and Combined (IAA, DLA, ARRA); Quarter 3 2012 Composite Data Products

    SciTech Connect

    Kurtz, J.; Wipke, K.; Sprik, S.; Ramsden, T.; Ainscough, C.; Saur, G.; Post, M.

    2013-01-01

    This report from the U.S. Department of Energy's National Renewable Energy Laboratory includes early fuel cell market composite data products for the third quarter of 2012 for American Recovery and Reinvestment Act (ARRA) and combined (IAA, DLA, ARRA) deployment projects.

  9. Early Fuel Cell Market Deployments: ARRA and Combined (IAA, DLA, ARRA): Quarter 4 2013 Composite Data Products

    SciTech Connect

    Kurtz, J.; Sprik, S.

    2014-06-01

    This report includes the composite data products (CDPs) for early fuel cell market deployments in quarter 4 of 2013. Results are presented for ARRA (projects funded by the American Recovery and Reinvestment Act of 2009 [ARRA]) and Combined (projects funded by DOE Interagency Agreements [IAA], Department of Defense Defense Logistics Agency [DLA], and ARRA).

  10. Validation of MIPAS IMK/IAA V5R_O3_224 ozone profiles

    NASA Astrophysics Data System (ADS)

    Laeng, A.; Grabowski, U.; von Clarmann, T.; Stiller, G.; Glatthor, N.; Höpfner, M.; Kellmann, S.; Kiefer, M.; Linden, A.; Lossow, S.; Sofieva, V.; Petropavlovskikh, I.; Hubert, D.; Bathgate, T.; Bernath, P.; Boone, C. D.; Clerbaux, C.; Coheur, P.; Damadeo, R.; Degenstein, D.; Frith, S.; Froidevaux, L.; Gille, J.; Hoppel, K.; McHugh, M.; Kasai, Y.; Lumpe, J.; Rapoe, N.; Toon, G.; Sano, T.; Suzuki, M.; Tamminen, J.; Urban, J.; Walker, K.; Weber, M.; Zawodny, J.

    2014-04-01

    We present the results of an extensive validation program of the most recent version of ozone vertical profiles retrieved with the IMK/IAA MIPAS research level 2 processor from version 5 spectral Level 1 data. The time period covered corresponds to the reduced spectral resolution period of the MIPAS instrument, i.e. January 2005-April 2012. The comparison with satellite instruments includes all post-2005 satellite limb and occultation sensors having measured the vertical profiles of tropospheric and stratospheric ozone: ACE-FTS, GOMOS, HALOE, HIRDLS, MLS, OSIRIS, POAM, SAGE II, SCIAMACHY, SMILES, and SMR. In addition, balloon-borne MkIV solar occultation measurements and groundbased Umkehr measurements have been included, as well as two nadir sensors: IASI and SBUV. For each reference dataset, bias determination and precision assessment are performed. Better agreement with reference instruments than for the previous data version, V5R_O3_220 (Laeng et al., 2013), is found: the known high bias around the ozone vmr peak is significantly reduced and the vertical resolution at 35 km has been improved. The agreement with limb and solar occultation reference instruments that have a known small bias vs. ozone sondes is within 7% in the lower and middle stratosphere and 5% in the upper troposphere. Around the ozone vmr peak, the agreement with most of satellite reference instruments is within 5%; this bias is as low as 3% for ACE-FTS, MLS, OSIRIS, POAM and SBUV.

  11. Final Report

    SciTech Connect

    Normanly, J.

    1999-11-29

    The primary goal was the characterization of tryptophan (Trp)-independent biosynthesis of the auxin indole-3-acetic acid (IAA). Our work and that of others indicates that indole is a precursor to IAA in a Trp-independent pathway and the objectives of this grant have been the isolation of indole-metabolizing genes from Arabidopsis.

  12. The defH9-iaaM auxin-synthesizing gene increases plant fecundity and fruit production in strawberry and raspberry

    PubMed Central

    Mezzetti, Bruno; Landi, Lucia; Pandolfini, Tiziana; Spena, Angelo

    2004-01-01

    Background The DefH9-iaaM gene fusion which is expressed specifically in placenta/ovules and promotes auxin-synthesis confers parthenocarpic fruit development to eggplant, tomato and tobacco. Transgenic DefH9-iaaM eggplants and tomatoes show increased fruit production due mainly to an improved fruit set. However, the weight of the fruits is also frequently increased. Results DefH9-iaaM strawberry and raspberry plants grown under standard cultivation conditions show a significant increase in fruit number and size and fruit yield. In all three Rosaceae species tested, Fragaria vesca, Fragaria x ananassa and Rubus idaeus, DefH9-iaaM plants have an increased number of flowers per inflorescence and an increased number of inflorescences per plant. This results in an increased number of fruits per plant. Moreover, the weight and size of transgenic fruits was also increased. The increase in fruit yield was approximately 180% in cultivated strawberry, 140% in wild strawberry, and 100% in raspberry. The DefH9-iaaM gene is expressed in the flower buds of all three species. The total IAA (auxin) content of young flower buds of strawberry and raspberry expressing the DefH9-iaaM gene is increased in comparison to untransformed flower buds. The DefH9-iaaM gene promotes parthenocarpy in emasculated flowers of both strawberry and raspberry. Conclusions The DefH9-iaaM gene is expressed and biologically active in Rosaceae. The DefH9-iaaM gene can be used, under cultivation conditions that allow pollination and fertilization, to increase fruit productivity significantly in Rosaceae species. The finding that the DefH9-iaaM auxin-synthesizing gene increases the number of inflorescences per plant and the number of flowers per inflorescence indicates that auxin plays a role in plant fecundity in these three perennial Rosaceae species. PMID:15113427

  13. Validation of MIPAS IMK/IAA V5R_O3_224 ozone profiles

    NASA Astrophysics Data System (ADS)

    Laeng, A.; Grabowski, U.; von Clarmann, T.; Stiller, G.; Glatthor, N.; Höpfner, M.; Kellmann, S.; Kiefer, M.; Linden, A.; Lossow, S.; Sofieva, V.; Petropavlovskikh, I.; Hubert, D.; Bathgate, T.; Bernath, P.; Boone, C. D.; Clerbaux, C.; Coheur, P.; Damadeo, R.; Degenstein, D.; Frith, S.; Froidevaux, L.; Gille, J.; Hoppel, K.; McHugh, M.; Kasai, Y.; Lumpe, J.; Rahpoe, N.; Toon, G.; Sano, T.; Suzuki, M.; Tamminen, J.; Urban, J.; Walker, K.; Weber, M.; Zawodny, J.

    2014-11-01

    We present the results of an extensive validation program of the most recent version of ozone vertical profiles retrieved with the IMK/IAA (Institute for Meteorology and Climate Research/Instituto de Astrofísica de Andalucía) MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) research level 2 processor from version 5 spectral level 1 data. The time period covered corresponds to the reduced spectral resolution period of the MIPAS instrument, i.e., January 2005-April 2012. The comparison with satellite instruments includes all post-2005 satellite limb and occultation sensors that have measured the vertical profiles of tropospheric and stratospheric ozone: ACE-FTS, GOMOS, HALOE, HIRDLS, MLS, OSIRIS, POAM, SAGE II, SCIAMACHY, SMILES, and SMR. In addition, balloon-borne MkIV solar occultation measurements and ground-based Umkehr measurements have been included, as well as two nadir sensors: IASI and SBUV. For each reference data set, bias determination and precision assessment are performed. Better agreement with reference instruments than for the previous data version, V5R_O3_220 (Laeng et al., 2014), is found: the known high bias around the ozone vmr (volume mixing ratio) peak is significantly reduced and the vertical resolution at 35 km has been improved. The agreement with limb and solar occultation reference instruments that have a known small bias vs. ozonesondes is within 7% in the lower and middle stratosphere and 5% in the upper troposphere. Around the ozone vmr peak, the agreement with most of the satellite reference instruments is within 5%; this bias is as low as 3% for ACE-FTS, MLS, OSIRIS, POAM and SBUV.

  14. Estimated quantitative amino acid requirements for Florida pompano reared in low-salinity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As with most marine carnivores, Florida pompano require relatively high crude protein diets to obtain optimal growth. Precision formulations to match the dietary indispensable amino acid (IAA) pattern to a species’ requirements can be used to lower the overall dietary protein. However IAA requirem...

  15. Protein quality as determined by the Digestible Indispensable Amino Acid Score: evaluation of factors underlying the calculation.

    PubMed

    Wolfe, Robert R; Rutherfurd, Shane M; Kim, Il-Young; Moughan, Paul J

    2016-09-01

    The Food and Agriculture Organization of the United Nations recently recommended the adoption of a new and improved scoring system (Digestible Indispensable Amino Acid Score [DIAAS]) to quantify dietary protein quality. The DIAAS is based on the relative digestible content of the indispensable amino acids (IAAs) and the amino acid requirement pattern. Factors involved in calculation of the DIAAS include: use of the content and profile of IAAs as the basis for quality; methods for determination of the protein and amino acid content of the protein source; accuracy of individual requirement values for IAAs; normalization of IAA requirements by the estimated average requirement for protein; and basing the DIAAS on the true ileal digestibility of each IAA in the test protein. This review outlines the rationale for including each of these factors in the calculation of the DIAAS and describes associated potential errors. PMID:27452871

  16. Effects of IAA, IBA, NAA, and GA3 on Rooting and Morphological Features of Melissa officinalis L. Stem Cuttings

    PubMed Central

    Guney, Kerim

    2013-01-01

    This study analyzed the potential of producing Melissa officinalis L. using stem cuttings. Four different hormones (IAA, IBA, NAA, and GA3) were applied to the cuttings, with and without buds, in two doses (1000 mg/L and 5000 mg/L), and after 60 days, 10 morphological characteristics of newly generated plants were detected, and a statistical analysis was carried out. The results of the study show that the cuttings with at least one bud must be used in order to produce M. officinalis using stem cuttings. Even though the auxin group hormones (IAA, IBA, and NAA) do not have an apparent effect on rooting percentage, these hormones were detected to affect the morphological characteristics of the newly generated plants, especially root generation. GA3 application has a considerable effect on stem height. PMID:23818834

  17. Effects of IAA, IBA, NAA, and GA3 on rooting and morphological features of Melissa officinalis L. stem cuttings.

    PubMed

    Sevik, Hakan; Guney, Kerim

    2013-01-01

    This study analyzed the potential of producing Melissa officinalis L. using stem cuttings. Four different hormones (IAA, IBA, NAA, and GA3) were applied to the cuttings, with and without buds, in two doses (1000 mg/L and 5000 mg/L), and after 60 days, 10 morphological characteristics of newly generated plants were detected, and a statistical analysis was carried out. The results of the study show that the cuttings with at least one bud must be used in order to produce M. officinalis using stem cuttings. Even though the auxin group hormones (IAA, IBA, and NAA) do not have an apparent effect on rooting percentage, these hormones were detected to affect the morphological characteristics of the newly generated plants, especially root generation. GA3 application has a considerable effect on stem height. PMID:23818834

  18. OCCURRENCE OF IODO-ACID AND IODO-THM DBPS IN U. S. CHLORAMINATED DRINKING WATERS

    EPA Science Inventory

    Iodo-acids were recently identified for the first time as DBPs in drinking water disinfected with chloramines. The iodo-acids identified included iodoacetic acid (IAA), bromoiodoacetic acid, (E)-3-bromo-3-iodo-propenoic acid, (Z)-3-bromo-3-iodo-propenoic acid, and (E)-2-iodo-3...

  19. Uptake and incorporation of labeled tryptophan isomers into IAA in the jsR sub 1 mutant of Lemna gibba

    SciTech Connect

    Baldi, B.G.; Maher, B.R.; Cohen, J.D. )

    1989-04-01

    Analyses of the IAA-overproducing mutant of Lemna have been initiated in order to study in vivo biosynthesis of IAA. Using radiolabelled tryptophan isomers prepared from commercial sources of {sup 14}C-D,L tryptophan by chiral separation kinetics of uptake of L and D tryptophan were determined for sterile cultures of individual jsR{sub 1} four-frond colonies. Over a 24 h period, about 50% of the radioactivity from {sup 14}C-L-TRP in media, or about 25% from {sup 14}C-D-TRP, was found in the plant tissue. Maximal rates of uptake were seen in the first six hors for both isomers. Endogenous levels of tryptophan determined in jsR{sub 1} as measures of pool sizes in vivo show 5 to 10 ug/g FW total tryptophan with less than 1% in the D isomer form. Information on uptake and endogenous pool sizes of tryptophan isomers is being used for feeding of stable isotope labeled tryptophan ({sup 13}C, {sup 14}N) to jsR{sub 1} at physiological levels. Analyses of incorporation of label into IAA using GC-MS and high resolution mass spectrometry are currently underway.

  20. IAA production by Bacillus sp. JH 2-2 promotes Indian mustard growth in the presence of hexavalent chromium.

    PubMed

    Shim, Jaehong; Kim, Jin-Won; Shea, Patrick J; Oh, Byung-Taek

    2015-05-01

    Bacillus sp. strain JH 2-2, isolated from the rhizosphere of plants at a multi-metal contaminated mine site, has the potential to reduce Cr(VI) to Cr(III) and promote plant growth by reducing Cr toxicity and producing IAA. The minimum inhibitory concentration of Cr(VI) to Bacillus sp. JH 2-2 was 1000 mg L(-1) and the strain reduced 99% of 10 mg Cr(VI) L(-1) to Cr(IV) within 24 h. Lower Cr(VI) stress (10 mg L(-1) ) stimulated IAA production, but much less IAA was produced at 30 or 50 mg Cr(VI) L(-1) . Inoculation with Bacillus sp. JH 2-2 increased the length of Brassica juncea L. roots by 364% and stems by 735% in the presence of 10 mg Cr(VI) L(-1) from those of uninoculated control plants. These findings suggest potential use of Bacillus sp. JH 2-2 to promote phytoremediation of soil contaminated with Cr(VI). PMID:25283159

  1. Identification of candidate genes JcARF19 and JcIAA9 associated with seed size traits in Jatropha.

    PubMed

    Ye, Jian; Liu, Peng; Zhu, Chengsong; Qu, Jing; Wang, Xianghua; Sun, Yanwei; Sun, Fei; Jiang, Yulin; Yue, Genhua; Wang, Chunming

    2014-12-01

    Jatropha curcas is a new promising bioenergy crop due to the high oil content in its seeds that can be converted into biodiesel. Seed size, a major determinant of Jatropha oil yield, is a target trait for Jatropha breeding. Due to the vital roles of phytohormone auxin in controlling seed and fruit development, we screened key genes in auxin pathway including ARF and IAA families and downstream effectors to identify candidate genes controlling seed size in Jatropha. As a result, JcARF19 was mapped in the major quantitative trait locus (QTL) region and significantly associated with seed length. By using expression QTL (eQTL) analysis to link variants with functional candidate genes, we provided evidences that seed traits were affected by the interaction of JcARF19 and JcIAA9. ARF19 and IAA9, involved in auxin signal transduction, were conserved in higher plants. These data including the single-nucleotide polymorphisms (SNPs) in the two genes could lead to utilization of the genes by integrating favored alleles into elite varieties through marker-assisted selection. PMID:25228410

  2. Bacteria isolated from roots and rhizosphere of Vitis vinifera retard water losses, induce abscisic acid accumulation and synthesis of defense-related terpenes in in vitro cultured grapevine.

    PubMed

    Salomon, María Victoria; Bottini, Rubén; de Souza Filho, Gonçalo Apolinário; Cohen, Ana Carmen; Moreno, Daniela; Gil, Mariana; Piccoli, Patricia

    2014-08-01

    Eleven bacterial strains were isolated at different soil depths from roots and rhizosphere of grapevines from a commercial vineyard. By 16S rRNA gene sequencing 10 different genera and 8 possible at species level were identified. From them, Bacillus licheniformis Rt4M10 and Pseudomonas fluorescens Rt6M10 were selected according to their characteristics as plant growth promoting rhizobacteria (PGPR). Both produced abscisic acid (ABA), indole-3-acetic acid (IAA) and the gibberellins A1 and A3 in chemically-defined medium. They also colonized roots of in vitro grown Vitis vinifera cv. Malbec plants. As result of bacterization ABA levels in 45 days-old in vitro plants were increased 76-fold by B. licheniformis and 40-fold by P. fluorescens as compared to controls. Both bacteria diminished plant water loss rate in correlation with increments of ABA. Twenty and 30 days post bacterization the plants incremented terpenes. The monoterpenes α-pinene, terpinolene, 4-carene, limonene, eucalyptol and lilac aldehyde A, and the sesquiterpenes α-bergamotene, α-farnesene, nerolidol and farnesol were assessed by gas chromatography-electron impact mass spectrometry analysis. α-Pinene and nerolidol were the most abundant (µg per g of tissue in plants bacterized with P. fluorescens). Only α-pinene, eucalyptol and farnesol were identified at low concentration in non-bacterized plants treated with ABA, while no terpenes were detected in controls. The results obtained along with others from literature suggest that B. licheniformis and P. fluorescens act as stress alleviators by inducing ABA synthesis so diminishing water losses. These bacteria also elicit synthesis of compounds of plant defense via an ABA independent mechanism. PMID:24118032

  3. Perturbation of Auxin Homeostasis by Overexpression of Wild-Type IAA15 Results in Impaired Stem Cell Differentiation and Gravitropism in Roots

    PubMed Central

    Yan, Da-Wei; Wang, Jing; Yuan, Ting-Ting; Hong, Li-Wei; Gao, Xiang; Lu, Ying-Tang

    2013-01-01

    Aux/IAAs interact with auxin response factors (ARFs) to repress their transcriptional activity in the auxin signaling pathway. Previous studies have focused on gain-of-function mutations of domain II and little is known about whether the expression level of wild-type Aux/IAAs can modulate auxin homeostasis. Here we examined the perturbation of auxin homeostasis by ectopic expression of wild-type IAA15. Root gravitropism and stem cell differentiation were also analyzed. The transgenic lines were less sensitive to exogenous auxin and exhibited low-auxin phenotypes including failures in gravity response and defects in stem cell differentiation. Overexpression lines also showed an increase in auxin concentration and reduced polar auxin transport. These results demonstrate that an alteration in the expression of wild-type IAA15 can disrupt auxin homeostasis. PMID:23472140

  4. OCCURRENCE OF IODO-ACID AND IODO-THM DISINFECTION BY-PRODUCTS IN CHLORAMINATED DRINKING WATER

    EPA Science Inventory

    Iodo-acids were recently identified for the first time as DBPs in drinking water disinfected with chloramines. The iodo-acids identified included iodoacetic acid (IAA), bromoiodoacetic acid, (E)-3-bromo-3-iodo-propenoic acid, (Z)-3-bromo-3-iodo-propenoic acid, and (E)-2-iodo-3...

  5. Amino acid profiles and digestible indispensable amino acid scores of proteins from the prioritized key foods in Bangladesh.

    PubMed

    Shaheen, Nazma; Islam, Saiful; Munmun, Sarah; Mohiduzzaman, Md; Longvah, Thingnganing

    2016-12-15

    Concentrations of standard amino acids were determined in the composite samples (representing 30 agro-ecological zones of Bangladesh) of six prioritized key dietary protein sources: Oryza sativa (rice), Triticum aestivum (wheat flour), Lens culinaris (lentils), Pangusius pangusius (pangas), Labeo rohita (rohu) and Oreochromis mossambicus (tilapia). Digestible indispensable amino acid scores (DIAAS) was calculated using published data on amino acids' digestibility to evaluate the protein quality of these foods. Indispensable amino acid (IAA) contents (mg IAA/g protein), found to be highest in pangas (430) and lowest in wheat (336), of all these analyzed foods exceeded the FAO recommended daily allowance (277mg IAA/g protein) and contributed on average 40% to total amino acid contents. Untruncated DIAAS values ranged from 51% (lysine) in wheat to 106% (histidine) in pangas and distinguished pangas, rohu, and tilapia containing 'excellent quality' protein (DIAAS>100%) with potential to complement lower quality protein of cereals, fruits, and vegetables. PMID:27451158

  6. Protective Effect of Edaravone in Primary Cerebellar Granule Neurons against Iodoacetic Acid-Induced Cell Injury

    PubMed Central

    Zhou, Xinhua; Zhu, Longjun; Wang, Liang; Guo, Baojian; Zhang, Gaoxiao; Sun, Yewei; Zhang, Zaijun; Lee, Simon Ming-Yuen; Yu, Pei; Wang, Yuqiang

    2015-01-01

    Edaravone (EDA) is clinically used for treatment of acute ischemic stroke in Japan and China due to its potent free radical-scavenging effect. However, it has yet to be determined whether EDA can attenuate iodoacetic acid- (IAA-) induced neuronal death in vitro. In the present study, we investigated the effect of EDA on damage of IAA-induced primary cerebellar granule neurons (CGNs) and its possible underlying mechanisms. We found that EDA attenuated IAA-induced cell injury in CGNs. Moreover, EDA significantly reduced intracellular reactive oxidative stress production, loss of mitochondrial membrane potential, and caspase 3 activity induced by IAA. Taken together, EDA protected CGNs against IAA-induced neuronal damage, which may be attributed to its antiapoptotic and antioxidative activities. PMID:26557222

  7. Blockage by gibberellic Acid of phytochrome effects on growth, auxin responses, and flavonoid synthesis in etiolated pea internodes.

    PubMed

    Russell, D W; Galston, A W

    1969-09-01

    Red light inhibits the growth of etiolated pea internodes, causes a shift toward higher indoleacetic acid (IAA) concentrations in the IAA dose-response curve of excised sections, and promotes the synthesis in intact internodes of kaempferol-3-triglucoside. Gibberellic acid (GA(3)) prevents all 3 effects, the first effect substantially and the last 2 completely. This suggests GA(3) blockage of an early or basic event initiated by the active form of phytochrome. The red light-induced shift in the IAA dose-response curve of excised sections is consistent with a light-induced increase in the activity of an IAA destruction system, since the magnitude of the red light inhibition varied with IAA concentration. The red light and GA(3) effects on growth and on flavonoid synthesis are consistent with the view that phytochrome may control growth by regulating the synthesis of phenolic compounds which act as cofactors in an IAA-oxidase system. GA(3) reversal of the red light-induced shift in the IAA dose-response curve involves both growth promotion and inhibition by GA(3) at different IAA concentrations and this, together with the GA(3) reversal of light-induced flavonoid synthesis, supports the suggested regulatory role of phenolic compounds in growth. PMID:16657193

  8. OCCURRENCE AND TOXICITY OF IODO-ACID DISINFECTION BY-PRODUCTS IN CHLORAMINATED DRINKING WATER

    EPA Science Inventory

    As part of a recent Nationwide Disinfection By-Product (DBP) Occurrence Study, iodo-acids were identified for the first time as DBPs in drinking water disinfected with chloramines. The iodo-acids identified included iodoacetic acid (IAA), bromoiodoacetic acid, (E)-3-bromo-3-iodo...

  9. Bacterial endophyte Sphingomonas sp. LK11 produces gibberellins and IAA and promotes tomato plant growth.

    PubMed

    Khan, Abdul Latif; Waqas, Muhammad; Kang, Sang-Mo; Al-Harrasi, Ahmed; Hussain, Javid; Al-Rawahi, Ahmed; Al-Khiziri, Salima; Ullah, Ihsan; Ali, Liaqat; Jung, Hee-Young; Lee, In-Jung

    2014-08-01

    Plant growth promoting endophytic bacteria have been identified as potential growth regulators of crops. Endophytic bacterium, Sphingomonas sp. LK11, was isolated from the leaves of Tephrosia apollinea. The pure culture of Sphingomonas sp. LK11 was subjected to advance chromatographic and spectroscopic techniques to extract and isolate gibberellins (GAs). Deuterated standards of [17, 17-(2)H2]-GA4, [17, 17-(2)H2]-GA9 and [17, 17-(2)H2]-GA20 were used to quantify the bacterial GAs. The analysis of the culture broth of Sphingomonas sp. LK11 revealed the existence of physiologically active gibberellins (GA4: 2.97 ± 0.11 ng/ml) and inactive GA9 (0.98 ± 0.15 ng/ml) and GA20 (2.41 ± 0.23). The endophyte also produced indole acetic acid (11.23 ± 0.93 μM/ml). Tomato plants inoculated with endophytic Sphingomonas sp. LK11 showed significantly increased growth attributes (shoot length, chlorophyll contents, shoot, and root dry weights) compared to the control. This indicated that such phyto-hormones-producing strains could help in increasing crop growth. PMID:24994010

  10. The Brain’s Response to an Essential Amino Acid-Deficient Diet and the Circuitous Route to a Better Meal

    PubMed Central

    Gietzen, Dorothy W.; Aja, Susan M.

    2012-01-01

    The essential (indispensable) amino acids (IAA) are neither synthesized nor stored in metazoans, yet they are the building blocks of protein. Survival depends on availability of these protein precursors, which must be obtained in the diet; it follows that food selection is critical for IAA homeostasis. If even one of the IAA is depleted, its tRNA becomes quickly deacylated and the levels of charged tRNA fall, leading to disruption of global protein synthesis. As they have priority in the diet, second only to energy, the missing IAA must be restored promptly or protein catabolism ensues. Animals detect and reject an IAA-deficient meal in 20 min, but how? Here, we review the molecular basis for sensing IAA depletion and repletion in the brain’s IAA chemosensor, the anterior piriform cortex (APC). As animals stop eating an IAA-deficient meal, they display foraging and altered choice behaviors, to improve their chances of encountering a better food. Within 2 h, sensory cues are associated with IAA depletion or repletion, leading to learned aversions and preferences that support better food selection. We show neural projections from the APC to appetitive and consummatory motor control centers, and to hedonic, motivational brain areas that reinforce these adaptive behaviors. PMID:22674217

  11. Enzymic synthesis of indole-3-acetyl-1-O-beta-d-glucose. II. Metabolic characteristics of the enzyme

    NASA Technical Reports Server (NTRS)

    Leznicki, A. J.; Bandurski, R. S.

    1988-01-01

    The synthesis of indole-3-acetyl-1-O-beta-D-glucose from indole-3-acetic acid (IAA) and uridine diphosphoglucose (UDPG) has been shown to be a reversible reaction with the equilibrium away from ester formation and toward formation of IAA. The enzyme occurs primarily in the liquid endosperm of the corn kernel but some activity occurs in the embryo. It is relatively specific showing no glucose ester formation with oxindole-3-acetic acid or 7-hydroxy-oxindole-3-acetic acid, and low activity with phenylpropene acids, such as rho-coumaric acid. The enzyme is also specific for the nucleotide sugar showing no activity with UDPGalactose or UDPXylose. The enzyme is inhibited by inorganic pyrophosphate, by phosphate esters and by phospholipids, particularly phosphatidyl ethanolamine. The enzyme is inhibited by zeatin, by 2,4-dichlorophenoxy-acetic acid, by IAA-myo-inositol and IAA-glucan, but not by zeatin riboside, and only weakly by gibberellic acid, abscisic acid and kinetin. The reaction is slightly stimulated by both calcium and calmodulin and, in some cases, by thiol compounds. The role of this enzyme in the homeostatic control of indole-3-acetic acid levels in Zea mays is discussed.

  12. Patterns of auxin and abscisic acid movement in the tips of gravistimulated primary roots of maize.

    PubMed

    Young, L M; Evans, M L

    1996-01-01

    Because both abscisic acid (ABA) and auxin (IAA) have been suggested as possible chemical mediators of differential growth during root gravitropism, we compared with redistribution of label from applied 3H-IAA and 3H-ABA during maize root gravitropism and examined the relative basipetal movement of 3H-IAA and 3H-ABA applied to the caps of vertical roots. Lateral movement of 3H-ABA across the tips of vertical roots was non-polar and about 2-fold greater than lateral movement of 3H-IAA (also non-polar). The greater movement of ABA was not due to enhanced uptake since the uptake of 3H-IAA was greater than that of 3H-ABA. Basipetal movement of label from 3H-IAA or 3H-ABA applied to the root cap was determined by measuring radioactivity in successive 1 mm sections behind the tip 90 minutes after application. ABA remained largely in the first mm (point of application) whereas IAA was concentrated in the region 2-4 mm from the tip with substantial levels found 7-8 mm from the tip. Pretreatment with inhibitors of polar auxin transport decreased both gravicurvature and the basipetal movement of IAA. When roots were placed horizontally, the movement of 3H-IAA from top to bottom across the cap was enhanced relative to movement from bottom to top whereas the pattern of movement of label from 3H-ABA was unaffected. These results are consistent with the hypothesis that IAA plays a role in root gravitropism but contrary to the idea that gravi-induced asymmetric distribution of ABA contributes to the response. PMID:11540494

  13. Patterns of auxin and abscisic acid movement in the tips of gravistimulated primary roots of maize

    NASA Technical Reports Server (NTRS)

    Young, L. M.; Evans, M. L.

    1996-01-01

    Because both abscisic acid (ABA) and auxin (IAA) have been suggested as possible chemical mediators of differential growth during root gravitropism, we compared with redistribution of label from applied 3H-IAA and 3H-ABA during maize root gravitropism and examined the relative basipetal movement of 3H-IAA and 3H-ABA applied to the caps of vertical roots. Lateral movement of 3H-ABA across the tips of vertical roots was non-polar and about 2-fold greater than lateral movement of 3H-IAA (also non-polar). The greater movement of ABA was not due to enhanced uptake since the uptake of 3H-IAA was greater than that of 3H-ABA. Basipetal movement of label from 3H-IAA or 3H-ABA applied to the root cap was determined by measuring radioactivity in successive 1 mm sections behind the tip 90 minutes after application. ABA remained largely in the first mm (point of application) whereas IAA was concentrated in the region 2-4 mm from the tip with substantial levels found 7-8 mm from the tip. Pretreatment with inhibitors of polar auxin transport decreased both gravicurvature and the basipetal movement of IAA. When roots were placed horizontally, the movement of 3H-IAA from top to bottom across the cap was enhanced relative to movement from bottom to top whereas the pattern of movement of label from 3H-ABA was unaffected. These results are consistent with the hypothesis that IAA plays a role in root gravitropism but contrary to the idea that gravi-induced asymmetric distribution of ABA contributes to the response.

  14. Draft Genome Sequence of Endophytic Bacterium Enterobacter asburiae PDA134, Isolated from Date Palm (Phoenix dactylifera L.) Roots

    PubMed Central

    2016-01-01

    In this report, a draft of the Enterobacter asburiae strain PDA134 genome was sequenced. This bacterial strain was isolated from the root tissue of a date palm, where it has the ability to produce 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and indole-3-acetic acid (IAA) under salinity stress. PMID:27540071

  15. Draft Genome Sequence of Endophytic Bacterium Enterobacter asburiae PDA134, Isolated from Date Palm (Phoenix dactylifera L.) Roots.

    PubMed

    Yaish, Mahmoud W

    2016-01-01

    In this report, a draft of the Enterobacter asburiae strain PDA134 genome was sequenced. This bacterial strain was isolated from the root tissue of a date palm, where it has the ability to produce 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and indole-3-acetic acid (IAA) under salinity stress. PMID:27540071

  16. Rapid construction of multiple sgRNA vectors and knockout of the Arabidopsis IAA2 gene using the CRISPR/Cas9 genomic editing technology.

    PubMed

    Dingyuan, Liu; Ting, Qiu; Xiaohui, Ding; Miaomiao, Li; Muyuan, Zhu; Junhui, Wang

    2016-08-01

    IAA2 is a member of the Aux/IAA auxin responsive gene family in Arabidopsis thaliana. No iaa2 mutant has been reported until now, thus hindering its further mechanistic investigations. The normal genomic editing technology of CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) uses only a single guide RNA (sgRNA) to target one site in a specific gene, and the gene knockout efficiency is not high. Instead, multiple sgRNAs can target multiple sites; therefore, the efficiency may be improved. In the present investigation, we used the golden-gate cloning strategy and two rounds of PCR reactions to combine three sgRNAs in the same entry vector. The final expression vector was obtained by LR reactions with the destination vector containing the Cas9 expression cassette. Four out of the six sgRNAs were effective, and we also obtained a lot of insertion and deletion mutations. Compared with one sgRNA approach, multiple sgRNAs displayed higher gene-knockout efficiency and produced more germ-line mutants. Thus, we established a more rapid and efficient method and generated five mutants for further studies of IAA2 functions. PMID:27531614

  17. IAA Space Exploration Conference

    NASA Technical Reports Server (NTRS)

    Davis, Jeffrey R.; Richard Elizabeth E.

    2014-01-01

    The NASA Human Health and Performance Center (NHHPC) was established in October 2010 to facilitate development of partnerships and collaborative projects in human health and performance with a focus on Earthspace benefits. The membership, which now stands at over 135 members from around the world, was developed to span the government, academic, industry and non-profit sectors, making the NHHPC a global convener in human health and performance. International members include organizations from Germany, the United Kingdom, Spain, Japan, South Africa, and India. The virtual center facilitates sharing of best practices and development of collaborative opportunities through a variety of vehicles, including annual in-person workshops, Innovation Lecture Series and Member to Member Connect webcasts, quarterly electronic newsletters, web postings, and electronic member announcements. The NHHPC has conducted four workshops leading to several collaborative projects between members, with the most recent workshop held focusing on new organizational business models for accelerating innovation. This short paper will discuss how the NHHPC facilitates partnerships and the collaborative research and technology developments projects with applications to both the NASA mission and life on Earth.

  18. Biosynthetic pathway of the phytohormone auxin in insects and screening of its inhibitors.

    PubMed

    Suzuki, Hiroyoshi; Yokokura, Junpei; Ito, Tsukasa; Arai, Ryoma; Yokoyama, Chiaki; Toshima, Hiroaki; Nagata, Shinji; Asami, Tadao; Suzuki, Yoshihito

    2014-10-01

    Insect galls are abnormal plant tissues induced by galling insects. The galls are used for food and habitation, and the phytohormone auxin, produced by the insects, may be involved in their formation. We found that the silkworm, a non-galling insect, also produces an active form of auxin, indole-3-acetic acid (IAA), by de novo synthesis from tryptophan (Trp). A detailed metabolic analysis of IAA using IAA synthetic enzymes from silkworms indicated an IAA biosynthetic pathway composed of a three-step conversion: Trp → indole-3-acetaldoxime → indole-3-acetaldehyde (IAAld) → IAA, of which the first step is limiting IAA production. This pathway was shown to also operate in gall-inducing sawfly. Screening of a chemical library identified two compounds that showed strong inhibitory activities on the conversion step IAAld → IAA. The inhibitors can be efficiently used to demonstrate the importance of insect-synthesized auxin in gall formation in the future. PMID:25111299

  19. Fluid diversion and sweep improvement with chemical gels in oil recovery processes. [Four types of gels: resorcinol-formaldehyde; colloidal silica; Cr sup 3+ (chloride)-xanthan; and Cr sup 3+ (acetate)-polyacrylamide

    SciTech Connect

    Seright, R.S.; Martin, F.D.

    1992-09-01

    The objectives of this project were to identify the mechanisms by which gel treatments divert fluids in reservoirs and to establish where and how gel treatments are best applied. Several different types of gelants were examined, including polymer-based gelants, a monomer-based gelant, and a colloidal-silica gelant. This research was directed at gel applications in water injection wells, in production wells, and in high-pressure gas floods. The work examined how the flow properties of gels and gelling agents are influenced by permeability, lithology, and wettability. Other goals included determining the proper placement of gelants, the stability of in-place gels, and the types of gels required for the various oil recovery processes and for different scales of reservoir heterogeneity. During this three-year project, a number of theoretical analyses were performed to determine where gel treatments are expected to work best and where they are not expected to be effective. The most important, predictions from these analyses are presented. Undoubtedly, some of these predictions will be controversial. However, they do provide a starting point in establishing guidelines for the selection of field candidates for gel treatments. A logical next step is to seek field data that either confirm or contradict these predictions. The experimental work focused on four types of gels: (1) resorcinol-formaldehyde, (2) colloidal silica, (3) Cr{sup 3+}(chloride)-xanthan, and (4) Cr{sup 3+}(acetate)-polyacrylamide. All experiments were performed at 41{degrees}C.

  20. A method for immunofluorescent demonstration of three coexisting neurotransmitters in rat brain and spinal cord, using the fluorophores fluorescein, lissamine rhodamine, and 7-amino-4-methylcoumarin-3-acetic acid.

    PubMed

    Wessendorf, M W; Appel, N M; Molitor, T W; Elde, R P

    1990-12-01

    Coexistence of neurotransmitters within single nerve fibers or terminals can be convincingly demonstrated by the use of multicolor immunofluorescence. The present study examined whether three-color immunocytochemical localization of coexisting neurotransmitters can be performed using the blue fluorophore AMCA. Spectrofluorometric examination of secondary antibodies conjugated with AMCA, fluorescein, and lissamine rhodamine showed that the peaks of excitation and emission were well separated and that dots of AMCA-conjugated IgG dried on slides were not visible when viewed using microscope filters for rhodamine and fluorescein. These findings suggest that AMCA might be suitable for three-color immunofluorescence. The usefulness of AMCA for triple labeling was tested directly by staining sections of rat brainstem and spinal cord for serotonin (5HT), substance P (SP), and either enkephalin (ENK) or prepro-thyrotropin-releasing hormone 160-169 (ppT), a marker peptide for thyrotropin-releasing hormone. Triple labeling for 5HT, SP, and ppT was observed in both brainstem and spinal cord but was only very rarely observed for 5HT,SP, and ENK. No evidence was found for artifactual triple labeling, although false negatives appeared to be possible in some circumstances. We conclude that AMCA can be combined with fluorescein and lissamine rhodamine for three-color immunofluorescent studies of coexisting neurotransmitters. In addition, the coexistence of 5HT with ENK appears to be much less common than the coexistence of 5HT with either SP or ppT. PMID:1701460

  1. The sensing of essential amino acid deficiency in the anterior piriform cortex, that requires the uncharged tRNA/GCN2 pathway, is sensitive to wortmannin but not rapamycin

    PubMed Central

    Hao, S.; Ross-Inta, C.M.; Gietzen, D.W.

    2013-01-01

    Animals detect and reject their first essential/indispensable amino acid (IAA) deficient meal within 20 min; this IAA sensing requires an intact anterior piriform cortex (APC). In the biochemical responses to IAA deficiency in the APC we have shown that: uncharged tRNA is the primary sensor; IAA transport is increased; and signaling, including the extracellular-regulated kinase (ERK1/2), is activated. The mammalian target of rapamycin (mTOR) is a potential AA sensor and is regulated by AA transport. Previously, the inhibitors, rapamycin for mTOR, wortmannin for phosphoinositide 3 kinase (PI3K) and PD98059 for ERK, each blocked the upregulation of the System A transporter in IAA depleted APC neurons. Here we injected these same inhibitors into the APC and measured intake of an IAA deficient diet. Rapamycin had no effect on the rejection of the IAA deficient diet, but wortmannin increased ERK activation and intake of the deficient diet before 40 min and PD98059 acted after 40 min to increase the second meal. While the specific wortmannin target involved in blocking the behavioral response remains unclear, we conclude that mTOR is dispensable for sensing IAA deficiency in the APC, and that ERK is associated with the secondary learned responses to IAA deficient diets. PMID:19800362

  2. The Impact of Reclassification from Division II to DI-AA and from Division I-AA to I-A on NCAA Member Institutions from 1993 to 2003

    ERIC Educational Resources Information Center

    Frieder, Laura L., Comp.; Fulks, Daniel L., Comp.

    2007-01-01

    Recent years have seen a number of National Collegiate Athletic Association (NCAA) Division II institutions seeking reclassification to Division I-AA and Division I-AA institutions moving to Division I-A. Yet, other schools that seem like natural candidates to reclassify have resisted. The purpose of this study is to investigate the impact of the…

  3. Transport of indoleacetic acid in intact corn coleoptiles. [Zea mays L

    SciTech Connect

    Parker, K.E.; Briggs, W.R. )

    1990-10-01

    We have characterized the transport of ({sup 3}H)indoleacetic acid (IAA) in intact corn (Zea mays L.) coleoptiles. We have used a wide range of concentrations of added IAA (28 femtomoles to 100 picomoles taken up over 60 minutes). The shape of the transport curve varies with the concentration of added IAA, although the rate of movement of the observed front of tracer is invariant with concentration. At the lowest concentration of tracer used, the labeled IAA in the transport stream is not detectably metabolized or immobilized, curvature does not develop as a result of tracer application, and normal phototropic and gravitropic responsiveness are not affected. Therefore we believe we are observing the transport of true tracer quantities of labeled auxin at this lowest concentration.

  4. Space traffic management: The new comprehensive approach for regulating the use of outer space—Results from the 2006 IAA cosmic study

    NASA Astrophysics Data System (ADS)

    Schrogl, Kai-Uwe

    2008-01-01

    October 2007 held two anniversaries: 50 years ago, Sputnik was launched and 40 years ago, the Outer Space Treaty entered into force. The first satellite and the foundation of the legal regime governing outer space mark the two decisive points for the use of outer space and its international regulation. During the past decades, space activities have taken a tremendous development in quantity and scope. Regulation has, however, not been able to keep pace with technology, so that today the legal environment shows more and more shortcomings. This paper argues that the growing problems of space law cannot be solved by "piecemeal engineering" any more but can only be overcome through a "big bang" comprehensive approach for regulating space activities: Space traffic management (STM). The debate on this issue has recently been strongly invigorated by the publication of the IAA Cosmic Study on STM. [IAA "Cosmic Study on Space Traffic Management", Paris 2006, in: edited by C. Contant-Jorgensen (Secretary of the Study Group), P. Lala, K.-U. Schrogl (Coordinators of the Study Group) (Eds.), The Study Group consisted of 16 contributors from numerous countries covering engineering, policy and legal aspects. Download at iaa/Studies/spacetraffic.pdf>[1].

  5. Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements

    NASA Astrophysics Data System (ADS)

    Stiller, G. P.; Kiefer, M.; Eckert, E.; von Clarmann, T.; Kellmann, S.; García-Comas, M.; Funke, B.; Leblanc, T.; Fetzer, E.; Froidevaux, L.; Gomez, M.; Hall, E.; Hurst, D.; Jordan, A.; Kämpfer, N.; Lambert, A.; McDermid, I. S.; McGee, T.; Miloshevich, L.; Nedoluha, G.; Read, W.; Schneider, M.; Schwartz, M.; Straub, C.; Toon, G.; Twigg, L. W.; Walker, K.; Whiteman, D. N.

    2011-07-01

    MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofisica de Andalucia (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radio sondes, frost point hygrometers, lidars, microwave radiometers and FTIR spectrometers. For MIPAS temperatures (version V4O_T_204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203) is well within 10 % of the data of all correlative instruments, while a high bias of up to 10 % is found in comparison to ground-based microwave instruments around 45 km. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40 % around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further significant biases have been detected. Cross-comparison to co-located observations of other satellite instruments (Aura/MLS, ACE-FTS, AIRS) is provided as well.

  6. Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements

    NASA Astrophysics Data System (ADS)

    Stiller, G. P.; Kiefer, M.; Eckert, E.; von Clarmann, T.; Kellmann, S.; García-Comas, M.; Funke, B.; Leblanc, T.; Fetzer, E.; Froidevaux, L.; Gomez, M.; Hall, E.; Hurst, D.; Jordan, A.; Kämpfer, N.; Lambert, A.; McDermid, I. S.; McGee, T.; Miloshevich, L.; Nedoluha, G.; Read, W.; Schneider, M.; Schwartz, M.; Straub, C.; Toon, G.; Twigg, L. W.; Walker, K.; Whiteman, D. N.

    2012-02-01

    MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofísica de Andalucía (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infra-red (FTIR) spectrometers. For MIPAS temperatures (version V4O_T_204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203) is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further

  7. Validation of MIPAS IMK-IAA Temperature, Water Vapor, and Ozone Profiles with MOHAVE-2009 Campaign Measurements

    NASA Technical Reports Server (NTRS)

    Stiller, Gabrielle; Kiefer, M.; Eckert, E.; von Clarmann, T.; Kellmann, S.; Garcia-Comas, M.; Funke, B.; Leblanc, T.; Fetzer, E.; Froidevaux, L.; Gomez, M.; Hall, E.; Hurst, D.; Jordan, A.; Kampfer, N.; Lambert, A.; McDermid, I. S.; McGee, T.; Miloshevich, L.; Nedoluha, G.; Read, W.; Schneider, M.; Schwartz, M.; Straub, C.; Toon, G.; Twigg, L. W.; Walker, K.; Whiteman, D. N.

    2012-01-01

    MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofisica de Andalucia (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infrared (FTIR) spectrometers. For MIPAS temperatures (version V4O_T_204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203) is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further

  8. Altered growth response to exogenous auxin and gibberellic acid by gravistimulation in pulvini of Avena sativa

    NASA Technical Reports Server (NTRS)

    Brock, T. G.; Kaufman, P. B.

    1988-01-01

    Pulvini of excised segments from oats (Avena sativa L. cv Victory) were treated unilaterally with indoleacetic acid (IAA) or gibberellic acid (GA3) with or without gravistimulation to assess the effect of gravistimulation on hormone action. Optimum pulvinus elongation growth (millimeters) and segment curvature (degrees) over 24 hours were produced by 100 micromolar IAA in vertical segments. The curvature response to IAA at levels greater than 100 micromolar, applied to the lower sides of gravistimulated (90 degrees) pulvini, was significantly less than the response to identical levels in vertical segments. Furthermore, the bending response of pulvini to 100 micromolar IAA did not vary significantly over a range of presentation angles between 0 and 90 degrees. In contrast, the response to IAA at levels less than 10 micromolar, with gravistimulation, was approximately the sum of the responses to gravistimulation alone and to IAA without gravistimulation. This was observed over a range of presentation angles. Also, GA3 (0.3-30 micromolar) applied to the lower sides of horizontal segments significantly enhanced pulvinus growth and segment curvature, although exogenous GA3 over a range of concentrations had no effect on pulvinus elongation growth or segment curvature in vertical segments. The response to GA3 (10 micromolar) plus IAA (1.0 or 100 micromolar) was additive for either vertical or horizontal segments. These results indicate that gravistimulation produces changes in pulvinus responsiveness to both IAA and GA3 and that the changes are unique for each growth regulator. It is suggested that the changes in responsiveness may result from processes at the cellular level other than changes in hormonal sensitivity.

  9. Bud emergence and shoot growth from mature citrus nodal segments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bud emergence and shoot growth from adult phase citrus nodal cultures were studied using Citrus mitis (calamondin), Citrus paradisi (grapefruit), and Citrus sinensis (sweet orange). The effects of 6-benzylaminopurine (BA), indole 3-acetic acid (IAA), and citrus type on shoot quality and growth fro...

  10. Current aspects of auxin biosynthesis in plants.

    PubMed

    Kasahara, Hiroyuki

    2015-01-01

    Auxin is an important plant hormone essential for many aspects of plant growth and development. Indole-3-acetic acid (IAA) is the most studied auxin in plants, and its biosynthesis pathway has been investigated for over 70 years. Although the complete picture of auxin biosynthesis remains to be elucidated, remarkable progress has been made recently in understanding the mechanism of IAA biosynthesis. Genetic and biochemical studies demonstrate that IAA is mainly synthesized from l-tryptophan (Trp) via indole-3-pyruvate by two-step reactions in Arabidopsis. While IAA is also produced from Trp via indole-3-acetaldoxime in Arabidopsis, this pathway likely plays an auxiliary role in plants of the family Brassicaceae. Recent studies suggest that the Trp-independent pathway is not a major route for IAA biosynthesis, but they reveal an important role for a cytosolic indole synthase in this pathway. In this review, I summarize current views and future prospects of IAA biosynthesis research in plants. PMID:26364770

  11. Enhancement of heavy metal accumulation by tissue specific co-expression of iaaM and ACC deaminase genes in plants.

    PubMed

    Zhang, Yong; Zhao, Lihong; Wang, Yao; Yang, Baoyu; Chen, Shiyun

    2008-06-01

    1-Aminocyclopropane deaminase (ACC) and tryptophan monooxygenase are two enzymes involved in plant senescence-inhibiting and growth-promoting regulation, respectively. In this study, two binary vectors were constructed in which the Agrobacterium iaaM gene was under the transcriptional control of a xylem-specific glycine-rich protein promoter alone, or co-expressed with the bacterial ACC deaminase gene, which was driven by the constitutive CaMV 35S promoter. Transgenic petunia shoots co-expressing both genes were able to root on medium supplemented with 7.5 mg l(-1) CoCl2. When T1 transgenic tobacco plants were grown in sand supplemented with Cu2+ and Co2+, tissue specific co-expression of both iaaM and ACC deaminase genes showed faster growth with larger biomass with a more extensive root system, and accumulated a greater amount of heavy metals than the empty vector control plants. When T1 transgenic tobacco plants were grown in soil watered with different concentrations of CuSO4, xylem specific expression of the iaaM gene caused the accumulation of more Cu2+ than the empty vector control at lower CuSO4 concentrations, but showed severe toxic symptoms at concentration of 100 mg l(-1) CuSO4. T1 transgenic plants co-expressing both genes accumulated more heavy metals into the plant shoots and can tolerate CuSO4 at 150 mg l(-1). In addition, plants co-expressing these two genes can grow well in a complex contaminated soil containing both inorganic and organic pollutants, while the growth of the control plants was greatly inhibited. PMID:18471863

  12. Structures and functions of insect arylalkylamine N-acetyltransferase (iaaNAT); a key enzyme for physiological and behavioral switch in arthropods

    PubMed Central

    Hiragaki, Susumu; Suzuki, Takeshi; Mohamed, Ahmed A. M.; Takeda, Makio

    2015-01-01

    The evolution of N-acetyltransfeases (NATs) seems complex. Vertebrate arylalkylamine N-acetyltransferase (aaNAT) has been extensively studied since it leads to the synthesis of melatonin, a multifunctional neurohormone prevalent in photoreceptor cells, and is known as a chemical token of the night. Melatonin also serves as a scavenger for reactive oxygen species. This is also true with invertebrates. NAT therefore has distinct functional implications in circadian function, as timezymes (aaNAT), and also xenobiotic reactions (arylamine NAT or simply NAT). NATs belong to a broader enzyme group, the GCN5-related N-acetyltransferase superfamily. Due to low sequence homology and a seemingly fast rate of structural differentiation, the nomenclature for NATs can be confusing. The advent of bioinformatics, however, has helped to classify this group of enzymes; vertebrates have two distinct subgroups, the timezyme type and the xenobiotic type, which has a wider substrate range including imidazolamine, pharmacological drugs, environmental toxicants and even histone. Insect aaNAT (iaaNAT) form their own clade in the phylogeny, distinct from vertebrate aaNATs. Arthropods are unique, since the phylum has exoskeleton in which quinones derived from N-acetylated monoamines function in coupling chitin and arthropodins. Monoamine oxidase (MAO) activity is limited in insects, but NAT-mediated degradation prevails. However, unexpectedly iaaNAT occurs not only among arthropods but also among basal deuterostomia, and is therefore more apomorphic. Our analyses illustrate that iaaNATs has unique physiological roles but at the same time it plays a role in a timezyme function, at least in photoperiodism. Photoperiodism has been considered as a function of circadian system but the detailed molecular mechanism is not well understood. We propose a molecular hypothesis for photoperiodism in Antheraea pernyi based on the transcription regulation of NAT interlocked by the circadian system

  13. An attempt to localize and identify the gravity sensing mechanism of plants

    NASA Technical Reports Server (NTRS)

    Bandurski, R. S.; Schulze, A.; Reinecke, D.

    1985-01-01

    The oxidation and transport of indole-3-acetic acid (IAA) in Zea mays is examined towards an understanding of the gravity-influenced promotion of growth in plants. An enzyme that oxidizes IAA to a nongrowth-promoting species has been partially purified, and determined to be stimulated by a lipoidal factor. Data suggest that the upward transport of IAA in the stele and outward movement from the stele into the mesophyll cortex is metabolically mediated, and possibly affected by the gravitational stimulus. It is postulated that hormone assymmetries can arise by 'potential-gating' of the transport channels between the various plant tissues.

  14. Patterns of auxin distribution during gravitational induction of reaction wood in poplar and pine.

    PubMed

    Hellgren, Jenny M; Olofsson, Kjell; Sundberg, Björn

    2004-05-01

    Gravistimulation of tree stems affects wood development by unilaterally inducing wood with modified properties, called reaction wood. Commonly, it also stimulates cambial growth on the reaction wood side. Numerous experiments involving applications of indole-3-acetic acid (IAA) or IAA-transport inhibitors have suggested that reaction wood is induced by a redistribution of IAA around the stem. However, in planta proof for this model is lacking. Therefore, we have mapped endogenous IAA distribution across the cambial region tissues in both aspen (Populus tremula, denoted poplar) and Scots pine (Pinus sylvestris) trees forming reaction wood, using tangential cryosectioning combined with sensitive gas chromatography-mass spectrometry analysis. Moreover, we have documented the kinetics of IAA during reaction wood induction in these species. Our analysis of endogenous IAA demonstrates that reaction wood is formed without any obvious alterations in IAA balance. This is in contrast to gravitropic responses in roots and shoots where a redistribution of IAA has been documented. It is also of interest that cambial growth on the tension wood side was stimulated without an increase in IAA. Taken together, our results suggest a role for signals other than IAA in the reaction wood response, or that the gravitational stimulus interacts with the IAA signal transduction pathway. PMID:15122024

  15. The rapid identification and quantification of iso-α-acids and reduced iso-α-acids in blood using UHPLC-MS/MS: validation of a novel marker for beer consumption.

    PubMed

    Rodda, Luke N; Gerostamoulos, Dimitri; Drummer, Olaf H

    2013-12-01

    A method for the detection of iso-α-acid (IAA) type ingredient congeners that are derived from the hop plant (Humulus lupulus L.) was developed to detect recent consumption of beer in blood. Three structurally similar but chemically altered IAA, also used as beer-specific ingredients, are known as "reduced IAA", consisting of the rho-, tetrahydro-, and hexahydro-IAA were also targeted. The use of a simple protein precipitation extraction and ultrahigh-performance liquid chromatography system coupled with a tandem mass spectrometer system enabled detection of these analytes in both antemortem and postmortem blood. Extracts were injected onto a C18 solid-core column under gradient elution to achieve separation of isobaric analogs and isomers within a 10-min run time. Electrospray ionization in negative multiple reaction monitoring mode was used to monitor three transitions for each of the analytes that were ultimately grouped together to form a calibration curve for quantification of each of the four IAA groups. The method was fully validated according to international guidelines that included extraction efficiency, matrix effects, process efficiency, ion suppression/enhancement of co-eluting analytes, selectivity, crosstalk, accuracy and precision, stabilities, and lower limits of quantification. Finally, applicability of the method described was demonstrated by the detection of IAA ingredient congeners in the blood of a volunteer following the consumption of a relatively small amount of beer in a pilot study. PMID:24177342

  16. Mechanism of specific inhibition of phototropism by phenylacetic acid in corn seedling

    SciTech Connect

    Vierstra, R.D.; Poff, K.L.

    1981-05-01

    Using geotropism as a control for phototropism, compounds similar to phenylacetic acid that phototreact with flavins and/or have auxin-like activity were examined for their ability to specifically inhibit phototropism in corn seedlings using geotropism as a control. Results using indole-3-acetic acid, napthalene-1-acetic acid, naphthalene-2-acetic acid, phenylacetic acid, and ..beta..-phenylpyruvic acid suggest that such compounds will specifically inhibit phototropism primarily because of their photoreactivity with flavins and not their auxin activity. In addition, the in vivo concentration of phenylacetic acid required to induce specificity was well below that required to stimulate coleoptile growth. Estimates of the percentage of photoreceptor pigment inactivated by phenylacetic acid (>10%) suggest that phenylacetic acid could be used to photoaffinity label the flavoprotein involved in corn seedling phototropism.

  17. IAA Producing Enterobacter sp. I-3 as a Potent Bio-herbicide Candidate for Weed Control: A Special Reference with Lettuce Growth Inhibition.

    PubMed

    Park, Jae-Man; Radhakrishnan, Ramalingam; Kang, Sang-Mo; Lee, In-Jung

    2015-06-01

    Development of bio-herbicides is an emerging method to weed management in agricultural field. Very few studies were conducted on identification of microbial bio-herbicides to weed control. The present study was aimed to isolate and identify the effective bio-herbicide potential bacterium from soil and assess their role on plant growth inhibition. Three-hundred and one rhizobacteria were isolated from agriculture field soil samples collected from various parts of Republic of Korea. Two bacterial strains, I-4-5 and I-3 were significantly reduced the seedling growth of radish when compared to their controls. The highest rate of seedling growth inhibition was observed in I-3 bacterial isolate treatment in lettuce and radish. The mechanism of an effective bio-herbicide I-3 to plant growth inhibition was determined by analyzing IAA in their culture medium. IAA biosynthesis pathway of Enterobacter sp. I-3 was identified as tryptophan-dependent pathway and its production was increased due to addition of tryptophan in culture medium as quantified by using GC-MS SIM. In an in vitro study revealed that I-3 bacterial culture exudate combined with tryptophan significantly decreased leaf length, leaf width, root length and increased the number of lateral roots of lettuce. Indeed, the genomic DNA of I-3 bacterium was isolated and 16S rDNA was sequenced to find out the name of the bacterium. Based on phylogenetic analysis, I-3 isolate was identified and named into Enterobacter sp. I-3. The results of this study suggest that the utilization of Enterobacter sp. I-3 to crop field can be act as a potential bio-herbicide against weed growth. PMID:25805908

  18. The auxin concentration in sixteen Chinese marine algae

    NASA Astrophysics Data System (ADS)

    Han, Lijun

    2006-09-01

    The author determined the occurrence of indole-3-acetic acid in sixteen Chinese marine algae collected from the east coast of China with fluorescence spectrophotometry (FS) and wheat coleoptile bioanalysis methods (WCB). The concentration of indole-3-acetic acid (IAA) presented was from 1.1 46.9 ng/g Fw (fresh weight) with FS and 5.3 110.2 ng/g Fw with WCB. The results by the two methods were in the orders of 10-3 103 ng/g Fw reported previously from multiple references.

  19. vProtein: Identifying Optimal Amino Acid Complements from Plant-Based Foods

    PubMed Central

    Woolf, Peter J.; Fu, Leeann L.; Basu, Avik

    2011-01-01

    Background Indispensible amino acids (IAAs) are used by the body in different proportions. Most animal-based foods provide these IAAs in roughly the needed proportions, but many plant-based foods provide different proportions of IAAs. To explore how these plant-based foods can be better used in human nutrition, we have created the computational tool vProtein to identify optimal food complements to satisfy human protein needs. Methods vProtein uses 1251 plant-based foods listed in the United States Department of Agriculture standard release 22 database to determine the quantity of each food or pair of foods required to satisfy human IAA needs as determined by the 2005 daily recommended intake. The quantity of food in a pair is found using a linear programming approach that minimizes total calories, total excess IAAs, or the total weight of the combination. Results For single foods, vProtein identifies foods with particularly balanced IAA patterns such as wheat germ, quinoa, and cauliflower. vProtein also identifies foods with particularly unbalanced IAA patterns such as macadamia nuts, degermed corn products, and wakame seaweed. Although less useful alone, some unbalanced foods provide unusually good complements, such as Brazil nuts to legumes. Interestingly, vProtein finds no statistically significant bias toward grain/legume pairings for protein complementation. These analyses suggest that pairings of plant-based foods should be based on the individual foods themselves instead of based on broader food group-food group pairings. Overall, the most efficient pairings include sweet corn/tomatoes, apple/coconut, and sweet corn/cherry. The top pairings also highlight the utility of less common protein sources such as the seaweeds laver and spirulina, pumpkin leaves, and lambsquarters. From a public health perspective, many of the food pairings represent novel, low cost food sources to combat malnutrition. Full analysis results are available online at http

  20. Iodoacetic acid, but not sodium iodate, creates an inducible swine model of photoreceptor damage.

    PubMed

    Noel, Jennifer M; Fernandez de Castro, Juan P; Demarco, Paul J; Franco, Luisa M; Wang, Wei; Vukmanic, Eric V; Peng, Xiaoyan; Sandell, Julie H; Scott, Patrick A; Kaplan, Henry J; McCall, Maureen A

    2012-04-01

    Our purpose was to find a method to create a large animal model of inducible photoreceptor damage. To this end, we tested in domestic swine the efficacy of two chemical toxins, known to create photoreceptor damage in other species: Iodoacetic Acid (IAA) and Sodium Iodate (NaIO(3)). Intravenous (IV) administration of NaIO(3) up to 90 mg/kg had no effect on retinal function and 110 mg/kg was lethal. IV administration of IAA (5-20 mg/kg) produced concentration-dependent changes in visual function as measured by full-field and multi-focal electroretinograms (ffERG and mfERG), and 30 mg/kg IAA was lethal. The IAA-induced effects measured at two weeks were stable through eight weeks post-injection, the last time point investigated. IAA at 7.5, 10, and 12 mg/kg produce a concentration-dependent reduction in both ffERG b-wave and mfERG N1-P1 amplitudes compared to baseline at all post-injection times. Comparisons of dark- and light-adapted ffERG b-wave amplitudes show a more significant loss of rod relative to cone function. The fundus of swine treated with ≥10 mg/kg IAA was abnormal with thinner retinal vessels and pale optic discs, and we found no evidence of bone spicule formation. Histological evaluations show concentration-dependent outer retinal damage that correlates with functional changes. We conclude that NaIO(3,) is not an effective toxin in swine. In contrast, IAA can be used to create a rapidly inducible, selective, stable and concentration-dependent model of photoreceptor damage in swine retina. Because of these attributes this large animal model of controlled photoreceptor damage should be useful in the investigation of treatments to replace damaged photoreceptors. PMID:22251455

  1. Response to gravity by Zea mays seedlings. I. Time course of the response

    NASA Technical Reports Server (NTRS)

    Bandurski, R. S.; Schulze, A.; Dayanandan, P.; Kaufman, P. B.

    1984-01-01

    Gravistimulation induces an asymmetric distribution of free indole-3-acetic acid (IAA) in the cortex-epidermis of the Zea mays L. cv 'Stowells Evergreen' mesocotyl within 15 minutes, the shortest time tested. IAA was measured by an isotope dilution method as the pentaflurobenzyl ester. The per cent IAA in the lower half of the mescotyl cortex was 56 to 57% at 15, 30, and 90 minutes after stimulus initiation. Curvature is detectable in the mescotyl within 3 minutes after beginning gravitropic stimulation. The rate of curvature of the mesocotyl increases during the first 60 minutes to maximum of about 30 degrees per hour. Thus, the growth asymmetry continues to increase for 45 minutes after hormone asymmetry is established. Free IAA occurs predominantly in the stele of the mesocotyl whereas esterified IAA is mainly in the mesocotyl cortex-epidermis. This compartmentation may permit determining in which tissue the hormone asymmetry arises. Current data suggest the asymmetry originated in the stele.

  2. Tobacco mosaic virus-directed reprogramming of auxin/indole acetic acid protein transcriptional responses enhances virus phloem loading.

    PubMed

    Collum, Tamara D; Padmanabhan, Meenu S; Hsieh, Yi-Cheng; Culver, James N

    2016-05-10

    Vascular phloem loading has long been recognized as an essential step in the establishment of a systemic virus infection. In this study, an interaction between the replication protein of tobacco mosaic virus (TMV) and phloem-specific auxin/indole acetic acid (Aux/IAA) transcriptional regulators was found to modulate virus phloem loading in an age-dependent manner. Promoter expression studies show that in mature tissues TMV 126/183-kDa-interacting Aux/IAAs predominantly express and accumulate within the nuclei of phloem companion cells (CCs). Furthermore, CC Aux/IAA nuclear localization is disrupted upon infection with an interacting virus. In situ analysis of virus spread shows that the inability to disrupt Aux/IAA CC nuclear localization correlates with a reduced ability to load into the vascular tissue. Subsequent systemic movement assays also demonstrate that a virus capable of disrupting Aux/IAA localization is significantly more competitive at moving out of older plant tissues than a noninteracting virus. Similarly, CC expression and overaccumulation of a degradation-resistant Aux/IAA-interacting protein was found to inhibit TMV accumulation and phloem loading selectively in flowering plants. Transcriptional expression studies demonstrate a role for Aux/IAA-interacting proteins in the regulation of salicylic and jasmonic acid host defense responses as well as virus-specific movement factors, including pectin methylesterase, that are involved in regulating plasmodesmata size-exclusion limits and promoting virus cell-to-cell movement. Combined, these findings indicate that TMV directs the reprogramming of auxin-regulated gene expression within the vascular phloem of mature tissues as a means to enhance phloem loading and systemic spread. PMID:27118842

  3. A comparison of gamma-aminobutyric acid and the semi-rigid analogues 4-aminotetrolic acid, 4-aminocrotonic acid and imidazole-4-acetic acid on the isolated superior cervical ganglion of the rat.

    PubMed Central

    Bowery, N G; Jones, G P

    1976-01-01

    1 The rat superior cervical ganglion possesses receptors for gamma-aminobutyric acid (GABA). This can be demonstrated in vitro by recording the changes in ganglionic surface potential which occur after the addition of GABA to the bathing solution. 2 The action of three conformationally-restricted analogues of GABA namely 4-aminotetrolic acid (4-ATA), trans 4-aminocrotonic acid (4-ACA) and imidazole-4-acetic acid (IAA) have been examined for activity at this peripheral receptor. 3 All three analogues depolarized the ganglion in a manner similar to GABA. Their actions were transient and were 'occluded' by GABA; also the dose-response curve in each case was parallel to that of GABA. Molar potencies relative to GABA (= 1) were 4-ACA = 1.48, IAA = 0.100, 4-ATA = 0.0028. 4 The action of each analogue could be blocked by the GABA antagonists bicuculline and tetramethylenedisulphotetramine at doses which had relatively little effect on responses to the cholinomimetic carbachol. 5 4-ACA and IAA (1 mM) significantly reduced the ganglionic accumulation of [3H]-GABA (0.2 muM) by 88% and 58% respectively whereas 4-ATA (1 mM), caused no significant reduction in [3H]-GABA accumulation. PMID:1260178

  4. Indoleacetic Acid and the Synthesis of Glucanases and Pectic Enzymes

    PubMed Central

    Datko, Anne Harmon; Maclachlan, G. A.

    1968-01-01

    Indoleacetic acid (IAA) and/or inhibitors of DNA, RNA or protein synthesis were added to the apex of decapitated seedlings of Pisum sativum L. var. Alaska. At various times up to 4 days, enzymic protein was extracted from a segment of epicotyl immediately below the apex and assayed for its ability to hydrolyse polysaccharides or their derivatives. With the exception of amylase, the total amounts per segment of all of the tested enzymes increased due to IAA treatment. The development of β-1,4-glucanase (cellulase) activity per unit of protein or fresh weight proceeded according to a typical sigmoid induction curve. Pectinase was formed for about 2 days in control segments and IAA treatment resulted in continued synthesis for at least another 2 days provided cell division took place. β-1,3-glucanase and pectinesterase activities were only enhanced by IAA to the extent that total protein levels increased. Reaction mechanisms for these effects and functions for the enzymes during growth are discussed. PMID:16656834

  5. Metabolism of tryptophol in higher and lower plants.

    PubMed

    Laćan, G; Magnus, V; Simaga, S; Iskrić, S; Hall, P J

    1985-07-01

    Bacteria, thallophytes, and seed plants (107 species), supplied with exogenous indole-3-ethanol (tryptophol), formed one or more of the following metabolites: O-acetyl tryptophol, an unknown tryptophol ester (or a set of structurally closely related esters), tryptophol glucoside, tryptophol galactoside, indole-3-acetic acid (IAA), and indole-3-carboxylic acid. The unknown ester was formed by all species examined; O-acetyl tryptophol appeared sporadically in representatives of most major taxonomic groups. Tryptophol galactoside was found in the algae Chlorella, Euglena, and Ochromonas. The glucoside was formed by many eucaryotic plants, but not by bacteria; it was a significant tryptophol metabolite in vascular plants. IAA, if detectable at all, was usually a minor metabolite, as should be expected, if tryptophol oxidase responds to feedback inhibition by IAA. Indole-3-carboxylic acid, formed by a few fungi and mosses, was the only tryptophol metabolite detected which is likely to be formed via IAA. PMID:16664264

  6. Metabolism of Tryptophol in Higher and Lower Plants 1

    PubMed Central

    Laćan, Goran; Magnus, Volker; Šimaga, Šumski; Iskrić, Sonja; Hall, Prudence J.

    1985-01-01

    Bacteria, thallophytes, and seed plants (107 species), supplied with exogenous indole-3-ethanol (tryptophol), formed one or more of the following metabolites: O-acetyl tryptophol, an unknown tryptophol ester (or a set of structurally closely related esters), tryptophol glucoside, tryptophol galactoside, indole-3-acetic acid (IAA), and indole-3-carboxylic acid. The unknown ester was formed by all species examined; O-acetyl tryptophol appeared sporadically in representatives of most major taxonomic groups. Tryptophol galactoside was found in the algae Chlorella, Euglena, and Ochromonas. The glucoside was formed by many eucaryotic plants, but not by bacteria; it was a significant tryptophol metabolite in vascular plants. IAA, if detectable at all, was usually a minor metabolite, as should be expected, if tryptophol oxidase responds to feedback inhibition by IAA. Indole-3-carboxylic acid, formed by a few fungi and mosses, was the only tryptophol metabolite detected which is likely to be formed via IAA. PMID:16664264

  7. Evidence for differential action of indoleacetic acid upon ion fluxes in single cells of Petroselinum sativum.

    PubMed

    Bentrup, F W; Pfrüner, H; Wagner, G

    1973-12-01

    The apparent influx of (36)Cl(-) and (86)Rb(+)/K(+) into cells from the higher plant Petroselinum sativum has been measured during the presence and absence in the culture medium of indolacetic acid (IAA) which is an essential auxin of these cells. While 10(-5) M IAA did not significantly affect the influx of (86)Rb(+)/K(+), it substantially reduced that of (36)Cl(-), i.e. by a factor 0.25 within 30 min. This differential action of IAA, which holds for a reasonable range of external pH, is assumed to bear on current hypotheses that the primary events of auxin action involve plasmalemma functions. PMID:24474466

  8. Ultrastructure of Sheep Primordial Follicles Cultured in the Presence of Indol Acetic Acid, EGF, and FSH

    PubMed Central

    Andrade, Evelyn Rabelo; Maddox-Hyttel, Poul; Landim-Alvarenga, Fernanda Da Cruz; Viana Silva, José Roberto; Alfieri, Amauri Alcindo; Seneda, Marcelo Marcondes; Figueiredo, José Ricardo; Toniolli, Ricardo

    2011-01-01

    The aim of this study was to investigate the ultrastructural characteristics of primordial follicles after culturing of sheep ovarian cortical slices in the presence of indol acetic acid (IAA), Epidermal Growth Factor (EGF), and FSH. To evaluate ultrastructure of primordial follicles cultured in MEM (control) or in MEM containing IAA, EGF, and FSH, fragments of cultured tissue were processes for transmission electron microscopy. Except in the control, primordial follicles cultured in supplemented media for 6 d were ultrastructurally normal. They had oocyte with intact nucleus and the cytoplasm contained heterogeneous-sized lipid droplets and numerous round or elongated mitochondria with intact parallel cristae were observed. Rough endoplasmic reticulum (RER) was rarely found. The granulosa cells cytoplasm contained a great number of mitochondria and abundant RER. In conclusion, the presence of IAA, EGF, and FSH helped to maintain ultrastructural integrity of sheep primordial follicles cultured in vitro. PMID:21188166

  9. Auxin Is Rapidly Induced by Herbivore Attack and Regulates a Subset of Systemic, Jasmonate-Dependent Defenses.

    PubMed

    Machado, Ricardo A R; Robert, Christelle A M; Arce, Carla C M; Ferrieri, Abigail P; Xu, Shuqing; Jimenez-Aleman, Guillermo H; Baldwin, Ian T; Erb, Matthias

    2016-09-01

    Plant responses to herbivore attack are regulated by phytohormonal networks. To date, the role of the auxin indole-3-acetic acid (IAA) in this context is not well understood. We quantified and manipulated the spatiotemporal patterns of IAA accumulation in herbivore-attacked Nicotiana attenuata plants to unravel its role in the regulation of plant secondary metabolism. We found that IAA is strongly, rapidly, and specifically induced by herbivore attack. IAA is elicited by herbivore oral secretions and fatty acid conjugate elicitors and is accompanied by a rapid transcriptional increase of auxin biosynthetic YUCCA-like genes. IAA accumulation starts 30 to 60 s after local induction and peaks within 5 min after induction, thereby preceding the jasmonate (JA) burst. IAA accumulation does not require JA signaling and spreads rapidly from the wound site to systemic tissues. Complementation and transport inhibition experiments reveal that IAA is required for the herbivore-specific, JA-dependent accumulation of anthocyanins and phenolamides in the stems. In contrast, IAA does not affect the accumulation of nicotine or 7-hydroxygeranyllinalool diterpene glycosides in the same tissue. Taken together, our results uncover IAA as a rapid and specific signal that regulates a subset of systemic, JA-dependent secondary metabolites in herbivore-attacked plants. PMID:27485882

  10. Auxin Input Pathway Disruptions Are Mitigated by Changes in Auxin Biosynthetic Gene Expression in Arabidopsis.

    PubMed

    Spiess, Gretchen M; Hausman, Amanda; Yu, Peng; Cohen, Jerry D; Rampey, Rebekah A; Zolman, Bethany K

    2014-06-01

    Auxin is a phytohormone involved in cell elongation and division. Levels of indole-3-acetic acid (IAA), the primary auxin, are tightly regulated through biosynthesis, degradation, sequestration, and transport. IAA is sequestered in reversible processes by adding amino acids, polyol or simple alcohols, or sugars, forming IAA conjugates, or through a two-carbon elongation forming indole-3-butyric acid. These sequestered forms of IAA alter hormone activity. To gain a better understanding of how auxin homeostasis is maintained, we have generated Arabidopsis (Arabidopsis thaliana) mutants that combine disruptions in the pathways, converting IAA conjugates and indole-3-butyric acid to free IAA. These mutants show phenotypes indicative of low auxin levels, including delayed germination, abnormal vein patterning, and decreased apical dominance. Root phenotypes include changes in root length, root branching, and root hair growth. IAA levels are reduced in the cotyledon tissue but not meristems or hypocotyls. In the combination mutants, auxin biosynthetic gene expression is increased, particularly in the YUCCA/Tryptophan Aminotransferase of Arabidopsis1 pathway, providing a feedback mechanism that allows the plant to compensate for changes in IAA input pathways and maintain cellular homeostasis. PMID:24891612

  11. Indole acetic acid production by fluorescent Pseudomonas spp. from the rhizosphere of Plectranthus amboinicus (Lour.) Spreng. and their variation in extragenic repetitive DNA sequences.

    PubMed

    Sethia, Bedhya; Mustafa, Mariam; Manohar, Sneha; Patil, Savita V; Jayamohan, Nellickal Subramanian; Kumudini, Belur Satyan

    2015-06-01

    Fluorescent Pseudomonas (FP) is a heterogenous group of growth promoting rhizobacteria that regulate plant growth by releasing secondary metabolic compounds viz., indole acetic acid (IAA), siderophores, ammonia and hydrogen cyanide. In the present study, IAA producing FPs from the rhizosphere of Plectranthus amboinicus were characterized morphologically, biochemically and at the molecular level. Molecular identification of the isolates were carried out using Pseudomonas specific primers. The effect of varying time (24, 48, 72 and 96 h), Trp concentrations (100, 200, 300, 400 and 500 μg x ml(-1)), temperature (10, 26, 37 and 50 ± 2 degrees C) and pH (6, 7 and 8) on IAA production by 10 best isolates were studied. Results showed higher IAA production at 72 h incubation, at 300 μg x ml(-1) Trp concentration, temperature 26 ± 2 degrees C and pH 7. TLC with acidified ethyl acetate extract showed that the IAA produced has a similar Rf value to that of the standard IAA. Results of TLC were confirmed by HPLC analysis. Genetic diversity of the isolates was also studied using 40 RAPD and 4 Rep primers. Genetic diversity parameters such as dominance, Shannon index and Simpson index were calculated. Out of 40 RAPD primers tested, 9 (2 OP-D series and 7 OP-E series) were shortlisted for further analysis. Studies using RAPD, ERIC, BOX, REP and GTG5 primers revealed that isolates exhibit significant diversity in repetitive DNA sequences irrespective of the rhizosphere. PMID:26155673

  12. Investigating organic molecules responsible of auxin-like activity of humic acid fraction extracted from vermicompost.

    PubMed

    Scaglia, Barbara; Nunes, Ramom Rachide; Rezende, Maria Olímpia Oliveira; Tambone, Fulvia; Adani, Fabrizio

    2016-08-15

    This work studied the auxin-like activity of humic acids (HA) obtained from vermicomposts produced using leather wastes plus cattle dung at different maturation stages (fresh, stable and mature). Bioassays were performed by testing HA concentrations in the range of 100-6000mgcarbonL(-1). (13)C CPMAS-NMR and GC-MS instrumental methods were used to assess the effect of biological processes and starting organic mixtures on HA composition. Not all HAs showed IAA-like activity and in general, IAA-like activity increased with the length of the vermicomposting process. The presence of leather wastes was not necessary to produce the auxin-like activity of HA, since HA extracted from a mix of cattle manure and sawdust, where no leather waste was added, showed IAA-like activity as well. CPMAS (13)CNMR revealed that HAs were similar independently of the mix used and that the humification process involved the increasing concentration of pre-existing alkali soluble fractions in the biomass. GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids and amino acids. The concentration of active molecules, rather than their simple presence in HA, determined the bio-stimulating effect, and a good linear regression between auxin-like activity and active stimulating molecules concentration was found (R(2)=-0.85; p<0.01, n=6). PMID:27100009

  13. Negative phototropism is seen in Arabidopsis inflorescences when auxin signaling is reduced to a minimal level by an Aux/IAA dominant mutation, axr2

    PubMed Central

    Sato, Atsuko; Sasaki, Shu; Matsuzaki, Jun; Yamamoto, Kotaro T.

    2015-01-01

    Inflorescences of a dominant mutant of Arabidopsis Aux/IAA7, axr2, showed negative phototropism with a similar fluence response curve to the positive phototropism of wild-type stems. Application of a synthetic auxin, NAA, and an inhibitor of polar auxin transport, NPA, increased and decreased respectively the magnitude of the phototropic response in the wild type, while in axr2 application of NAA reduced the negative phototropic response and NPA had no effect. Decapitation of the apex induced a small negative phototropism in wild-type stems, and had no effect in axr2 plants. Inflorescences of the double mutants of auxin transporters, pgp1 pgp19, showed no phototropic response, while decapitation resulted in a negative phototropic response. These results suggest that negative phototropism can occur when the level of auxin or of auxin signaling is reduced to a minimal level, and that in plant axial organs the default phototropic response to unilateral blue light may be negative. Expression of axr2 protein by an endodermis-specific promoter resulted in agravitropism of inflorescences in a similar way to that of axr2, but phototropism was normal, confirming that the endodermis does not play a critical role in phototropism. PMID:25738325

  14. Negative phototropism is seen in Arabidopsis inflorescences when auxin signaling is reduced to a minimal level by an Aux/IAA dominant mutation, axr2.

    PubMed

    Sato, Atsuko; Sasaki, Shu; Matsuzaki, Jun; Yamamoto, Kotaro T

    2015-01-01

    Inflorescences of a dominant mutant of Arabidopsis Aux/IAA7, axr2, showed negative phototropism with a similar fluence response curve to the positive phototropism of wild-type stems. Application of a synthetic auxin, NAA, and an inhibitor of polar auxin transport, NPA, increased and decreased respectively the magnitude of the phototropic response in the wild type, while in axr2 application of NAA reduced the negative phototropic response and NPA had no effect. Decapitation of the apex induced a small negative phototropism in wild-type stems, and had no effect in axr2 plants. Inflorescences of the double mutants of auxin transporters, pgp1 pgp19, showed no phototropic response, while decapitation resulted in a negative phototropic response. These results suggest that negative phototropism can occur when the level of auxin or of auxin signaling is reduced to a minimal level, and that in plant axial organs the default phototropic response to unilateral blue light may be negative. Expression of axr2 protein by an endodermis-specific promoter resulted in agravitropism of inflorescences in a similar way to that of axr2, but phototropism was normal, confirming that the endodermis does not play a critical role in phototropism. PMID:25738325

  15. Evidence of oxidative attenuation of auxin signalling.

    PubMed

    Peer, Wendy Ann; Cheng, Yan; Murphy, Angus S

    2013-06-01

    Indole-3-acetic acid (IAA) is the principle auxin in Arabidopsis and is synthesized primarily in meristems and nodes. Auxin is transported to distal parts of the plant in response to developmental programming or environmental stimuli to activate cell-specific responses. As with any signalling event, the signal must be attenuated to allow the system to reset. Local auxin accumulations are thus reduced by conjugation or catabolism when downstream responses have reached their optima. In most cell types, localized auxin accumulation increases both reactive oxygen species (ROS) and an irreversible catabolic product 2-oxindole-3-acid acid (oxIAA). oxIAA is inactive and does not induce expression of the auxin-responsive reporters DR5 or 2XD0. Here it is shown that oxIAA is not transported from cell to cell, although it appears to be a substrate for the ATP-binding cassette subfamily G (ABCG) transporters that are positioned primarily on the outer lateral surface of the root epidermis. However, oxIAA and oxIAA-Glc levels are higher in ABCB mutants that accumulate auxin due to defective cellular export. Auxin-induced ROS production appears to be at least partially mediated by the NAD(P)H oxidase RbohD. oxIAA levels are higher in mutants that lack ROS-scavenging flavonoids (tt4) and are lower in mutants that accumulate excess flavonols (tt3). These data suggest a model where IAA signalling is attenuated by IAA catabolism to oxIAA. Flavonoids appear to buffer ROS accumulations that occur with localized increases in IAA. This buffering of IAA oxidation would explain some growth responses observed in flavonoid-deficient mutants that cannot be explained by their established role in partially inhibiting auxin transport. PMID:23709674

  16. Protocol: High-throughput and quantitative assays of auxin and auxin precursors from minute tissue samples

    PubMed Central

    2012-01-01

    Background The plant hormone auxin, indole-3-acetic acid (IAA), plays important roles in plant growth and development. The signaling response to IAA is largely dependent on the local concentration of IAA, and this concentration is regulated by multiple mechanisms in plants. Therefore, the precise quantification of local IAA concentration provides insights into the regulation of IAA and its biological roles. Meanwhile, pathways and genes involved in IAA biosynthesis are not fully understood, so it is necessary to analyze the production of IAA at the metabolite level for unbiased studies of IAA biosynthesis. Results We have developed high-throughput methods to quantify plant endogenous IAA and its biosynthetic precursors including indole, tryptophan, indole-3-pyruvic acid (IPyA), and indole-3-butyric acid (IBA). The protocol starts with homogenizing plant tissues with stable-labeled internal standards added, followed by analyte purification using solid phase extraction (SPE) tips and analyte derivatization. The derivatized analytes are finally analyzed by selected reaction monitoring on a gas chromatograph-mass spectrometer (GC-MS/MS) to determine the precise abundance of analytes. The amount of plant tissue required for the assay is small (typically 2–10 mg fresh weight), and the use of SPE tips is simple and convenient, which allows preparation of large sets of samples within reasonable time periods. Conclusions The SPE tips and GC-MS/MS based method enables high-throughput and accurate quantification of IAA and its biosynthetic precursors from minute plant tissue samples. The protocol can be used for measurement of these endogenous compounds using isotope dilution, and it can also be applied to analyze IAA biosynthesis and biosynthetic pathways using stable isotope labeling. The method will potentially advance knowledge of the role and regulation of IAA. PMID:22883136

  17. Identification of a 23 kDa protein from maize photoaffinity-labelled with 5-azido-[7-3H]indol-3-ylacetic acid.

    PubMed Central

    Feldwisch, J; Zettl, R; Campos, N; Palme, K

    1995-01-01

    A 23 kDa protein (p23) was identified in microsomal extracts from maize coleoptiles by photoaffinity labelling with 5-azido-[7-3H]indol-3-ylacetic acid ([3H]N3IAA). Labelling of p23 was blocked by unlabelled IAA, N3IAA, indol-3-ylbutyric acid and indol-3-yl-lactate. In addition, labelling was efficiently decreased by tryptophan, as well as by the scavenger p-aminobenzoic acid. Labelling was, however, not affected by synthetic auxins such as 1-naphthylacetic acid or 2,4-dichlorophenoxyacetic acid. Competition data suggest that the label was probably bound via the indole ring, and hence labelling was not specific for auxins. The 23 kDa protein was solubilized from crude microsomes by extraction with Triton X-100 and purified to homogeneity by ion-exchange, size-exclusion and reversed-phase chromatography. After electroblotting, the amino acid sequences of the p23 N-terminus as well as the several tryptic peptides were obtained. Database comparisons revealed sequence identity with a maize manganese superoxide dismutase. We conclude that photoaffinity labelling of p23 was pseudo-affinity, and therefore the binding site for IAA is not specific. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:7848285

  18. Translation Start Sequences Affect the Efficiency of Silencing of Agrobacterium tumefaciens T-DNA Oncogenes1

    PubMed Central

    Lee, Hyewon; Humann, Jodi L.; Pitrak, Jennifer S.; Cuperus, Josh T.; Parks, T. Dawn; Whistler, Cheryl A.; Mok, Machteld C.; Ream, L. Walt

    2003-01-01

    Agrobacterium tumefaciens oncogenes cause transformed plant cells to overproduce auxin and cytokinin. Two oncogenes encode enzymes that convert tryptophan to indole-3-acetic acid (auxin): iaaM (tryptophan mono-oxygenase) and iaaH (indole-3-acetamide hydrolase). A third oncogene (ipt) encodes AMP isopentenyl transferase, which produces cytokinin (isopentenyl-AMP). Inactivation of ipt and iaaM (or iaaH) abolishes tumorigenesis. Because adequate means do not exist to control crown gall, we created resistant plants by introducing transgenes designed to elicit posttranscriptional gene silencing (PTGS) of iaaM and ipt. Transgenes that elicit silencing trigger sequence-specific destruction of the inducing RNA and messenger RNAs with related sequences. Although PTGS has proven effective against a variety of target genes, we found that a much higher percentage of transgenic lines silenced iaaM than ipt, suggesting that transgene sequences influenced the effectiveness of PTGS. Sequences required for oncogene silencing included a translation start site. A transgene encoding a translatable sense-strand RNA from the 5′ end of iaaM silenced the iaaM oncogene, but deletion of the translation start site abolished the ability of the transgene to silence iaaM. Silencing A. tumefaciens T-DNA oncogenes is a new and effective method to produce plants resistant to crown gall disease. PMID:12972655

  19. Urban and semi-rural observations of carboxylic acids and carbonyls

    NASA Astrophysics Data System (ADS)

    Granby, Kit; Christensen, Carsten S.; Lohse, Christian

    In a busy street in Central Copenhagen winter mean concentrations (ppbv) were for formic acid, (0.7 ± 0.3); acetic acid, (1.2 ± 0.5); formaldehyde, (2.6 ± 0.7); acetaldehyde, (1.0 ± 0.7); and acetone, (1.0 ± 0.5). Simultaneous measurements at a semi-rural site 30 km west of Copenhagen showed mean concentrations (ppbv) of: formic acid, (0.6 ± 0.3); acetic acid, (1.0 ± 0.5); formaldehyde, (0.9 ± 0.5); acetaldehyde, (0.7 ± 0.4); and acetone, (0.9 ± 0.4). The similar concentrations of formic acid and acetic acid at the two sites in Denmark when NO y concentrations were one order of magnitude lower at the semi-rural site indicate that primary emission from automobiles was not an important source of the carboxylic acids. In a busy street in Brussels, Belgium summer mean concentrations (ppbv) were for formic acid, (3.6 ± 1.6) and acetic acid, (4.0 ± 2.0). Weaker diurnal variation of formic acid and acetic acid than of the directly emitted NO y and CO in both Copenhagen and Brussels further support sources of the carboxylic acids other than car traffic. For formaldehyde the strong correlations with gas NO y and CO indicate that direct emission from automobile is a source. Acetone shows similar concentrations at the urban and semirural sites and weak correlations with CO and gas NO y which indicate other sources than traffic emission. For acetone and the carboxylic acids the similar concentrations at the urban and semi-rural site may be explained by a regional photochemical source, i.e. oxidation of reactive hydrocarbons in polluted air masses carried to the region by long-range transport.

  20. The bHLH Transcription Factor bHLH104 Interacts with IAA-LEUCINE RESISTANT3 and Modulates Iron Homeostasis in Arabidopsis

    PubMed Central

    Zhang, Jie; Liu, Bing; Li, Mengshu; Feng, Dongru; Jin, Honglei; Wang, Peng; Liu, Jun; Xiong, Feng; Wang, Jinfa; Wang, Hong-Bin

    2015-01-01

    Iron (Fe) is an indispensable micronutrient for plant growth and development. The regulation of Fe homeostasis in plants is complex and involves a number of transcription factors. Here, we demonstrate that a basic helix-loop-helix (bHLH) transcription factor, bHLH104, belonging to the IVc subgroup of bHLH family, acts as a key component positively regulating Fe deficiency responses. Knockout of bHLH104 in Arabidopsis thaliana greatly reduced tolerance to Fe deficiency, whereas overexpression of bHLH104 had the opposite effect and led to accumulation of excess Fe in soil-grown conditions. The activation of Fe deficiency-inducible genes was substantially suppressed by loss of bHLH104. Further investigation showed that bHLH104 interacted with another IVc subgroup bHLH protein, IAA-LEUCINE RESISTANT3 (ILR3), which also plays an important role in Fe homeostasis. Moreover, bHLH104 and ILR3 could bind directly to the promoters of Ib subgroup bHLH genes and POPEYE (PYE) functioning in the regulation of Fe deficiency responses. Interestingly, genetic analysis showed that loss of bHLH104 could decrease the tolerance to Fe deficiency conferred by the lesion of BRUTUS, which encodes an E3 ligase and interacts with bHLH104. Collectively, our data support that bHLH104 and ILR3 play pivotal roles in the regulation of Fe deficiency responses via targeting Ib subgroup bHLH genes and PYE expression. PMID:25794933

  1. The bHLH transcription factor bHLH104 interacts with IAA-LEUCINE RESISTANT3 and modulates iron homeostasis in Arabidopsis.

    PubMed

    Zhang, Jie; Liu, Bing; Li, Mengshu; Feng, Dongru; Jin, Honglei; Wang, Peng; Liu, Jun; Xiong, Feng; Wang, Jinfa; Wang, Hong-Bin

    2015-03-01

    Iron (Fe) is an indispensable micronutrient for plant growth and development. The regulation of Fe homeostasis in plants is complex and involves a number of transcription factors. Here, we demonstrate that a basic helix-loop-helix (bHLH) transcription factor, bHLH104, belonging to the IVc subgroup of bHLH family, acts as a key component positively regulating Fe deficiency responses. Knockout of bHLH104 in Arabidopsis thaliana greatly reduced tolerance to Fe deficiency, whereas overexpression of bHLH104 had the opposite effect and led to accumulation of excess Fe in soil-grown conditions. The activation of Fe deficiency-inducible genes was substantially suppressed by loss of bHLH104. Further investigation showed that bHLH104 interacted with another IVc subgroup bHLH protein, IAA-LEUCINE RESISTANT3 (ILR3), which also plays an important role in Fe homeostasis. Moreover, bHLH104 and ILR3 could bind directly to the promoters of Ib subgroup bHLH genes and POPEYE (PYE) functioning in the regulation of Fe deficiency responses. Interestingly, genetic analysis showed that loss of bHLH104 could decrease the tolerance to Fe deficiency conferred by the lesion of BRUTUS, which encodes an E3 ligase and interacts with bHLH104. Collectively, our data support that bHLH104 and ILR3 play pivotal roles in the regulation of Fe deficiency responses via targeting Ib subgroup bHLH genes and PYE expression. PMID:25794933

  2. Early embryo development in Fucus distichus is auxin sensitive

    NASA Technical Reports Server (NTRS)

    Basu, Swati; Sun, Haiguo; Brian, Leigh; Quatrano, Ralph L.; Muday, Gloria K.

    2002-01-01

    Auxin and polar auxin transport have been implicated in controlling embryo development in land plants. The goal of these studies was to determine if auxin and auxin transport are also important during the earliest stages of development in embryos of the brown alga Fucus distichus. Indole-3-acetic acid (IAA) was identified in F. distichus embryos and mature tissues by gas chromatography-mass spectroscopy. F. distichus embryos accumulate [(3)H]IAA and an inhibitor of IAA efflux, naphthylphthalamic acid (NPA), elevates IAA accumulation, suggesting the presence of an auxin efflux protein complex similar to that found in land plants. F. distichus embryos normally develop with a single unbranched rhizoid, but growth on IAA leads to formation of multiple rhizoids and growth on NPA leads to formation of embryos with branched rhizoids, at concentrations that are active in auxin accumulation assays. The effects of IAA and NPA are complete before 6 h after fertilization (AF), which is before rhizoid germination and cell division. The maximal effects of IAA and NPA are between 3.5 and 5 h AF and 4 and 5.5 h AF, respectively. Although, the location of the planes of cell division was significantly altered in NPA- and IAA-treated embryos, these abnormal divisions occurred after abnormal rhizoid initiation and branching was observed. The results of this study suggest that auxin acts in the formation of apical basal patterns in F. distichus embryo development.

  3. Early Embryo Development in Fucus distichus Is Auxin Sensitive1

    PubMed Central

    Basu, Swati; Sun, Haiguo; Brian, Leigh; Quatrano, Ralph L.; Muday, Gloria K.

    2002-01-01

    Auxin and polar auxin transport have been implicated in controlling embryo development in land plants. The goal of these studies was to determine if auxin and auxin transport are also important during the earliest stages of development in embryos of the brown alga Fucus distichus. Indole-3-acetic acid (IAA) was identified in F. distichus embryos and mature tissues by gas chromatography-mass spectroscopy. F. distichus embryos accumulate [3H]IAA and an inhibitor of IAA efflux, naphthylphthalamic acid (NPA), elevates IAA accumulation, suggesting the presence of an auxin efflux protein complex similar to that found in land plants. F. distichus embryos normally develop with a single unbranched rhizoid, but growth on IAA leads to formation of multiple rhizoids and growth on NPA leads to formation of embryos with branched rhizoids, at concentrations that are active in auxin accumulation assays. The effects of IAA and NPA are complete before 6 h after fertilization (AF), which is before rhizoid germination and cell division. The maximal effects of IAA and NPA are between 3.5 and 5 h AF and 4 and 5.5 h AF, respectively. Although, the location of the planes of cell division was significantly altered in NPA- and IAA-treated embryos, these abnormal divisions occurred after abnormal rhizoid initiation and branching was observed. The results of this study suggest that auxin acts in the formation of apical basal patterns in F. distichus embryo development. PMID:12226509

  4. Sites and homeostatic control of auxin biosynthesis in Arabidopsis during vegetative growth.

    PubMed

    Ljung, K; Bhalerao, R P; Sandberg, G

    2001-11-01

    The distribution and biosynthesis of indole-3-acetic acid (IAA) was investigated during early plant development in Arabidopsis. The youngest leaves analysed, less than 0.5 mm in length, contained 250 pg mg(-1) of IAA and also exhibited the highest relative capacity to synthesize this hormone. A decrease of nearly one hundred-fold in IAA content occurred as the young leaves expanded to their full size, and this was accompanied by a clear shift in both pool size and IAA synthesis capacity. The correlation between high IAA content and intense cell division was further verified in tobacco leaves, where a detailed analysis revealed that dividing mesophyll tissue contained ten-fold higher IAA levels than tissue growing solely by elongation. We demonstrated that all parts of the young Arabidopsis plant can potentially contribute to the auxin needed for growth and development, as not only young leaves, but also all other parts of the plant such as cotyledons, expanding leaves and root tissues have the capacity to synthesize IAA de novo. We also observed that naphthylphthalamic acid (NPA) treatment induced tissue-dependent feedback inhibition of IAA biosynthesis in expanding leaves and cotyledons, but intriguingly not in young leaves or in the root system. This observation supports the hypothesis that there is a sophisticated tissue-specific regulatory mechanism for auxin biosynthesis. Finally, a strict requirement for maintaining the pool sizes of IAA was revealed as reductions in leaf expansion followed both decreases and increases in the IAA levels in developing leaves. This indicates that leaves are not only important sources for IAA synthesis, but that normal leaf expansion depends on rigorous control of IAA homeostasis. PMID:11737783

  5. A fast, simple, and reliable hydrophilic interaction liquid chromatography method for the determination of ascorbic and isoascorbic acids.

    PubMed

    Barros, Ana I R N A; Silva, Ana P; Gonçalves, Berta; Nunes, Fernando M

    2010-03-01

    A reliable method for the determination of total vitamin C must be able to resolve ascorbic acid (AA) and the epimeric isoascorbic acid (IAA) and determine the sum of AA and its oxidized form dehydroascorbic acid. AA and IAA are polar molecules with a low retention time in conventional reversed phase systems, and hence of difficult resolution. Hydrophilic interaction chromatography using a TSKgel Amide-80 stationary phase with isocratic elution was successful in resolving the two epimers. The column was compatible with injections of high concentrations of metaphosphoric acid, tris(2-carboxyethyl)-phosphine, and EDTA without drift of baseline and retention time. Total AA and IAA were extracted, stabilized, and reduced in one step at 40 °C, using 5% m-phosphoric acid, 2 mM of EDTA, and 2 mM of tris(2-carboxyethyl)-phosphine as reducing agent. This simple, fast, and robust hydrophilic interaction chromatography-DAD method was applied for the analysis of food products namely fruit juices, chestnut, and ham and also in pharmaceutical and multivitamin tablets. Method validation was performed on the food products, including parameters of precision, accuracy, linearity, limit of detection, and quantification (LOQ). The absence of matrix interferences was assessed by the standard addition method and Youden calibration. The method was fast, accurate, and precise with a LOQ(AA) of 1.5 mg/L and LOQ(IAA) of 3.7 mg/L. The simple experimental procedure, completed in 1 h, the possibility of using IAA as an internal standard, and low probability of artifacts are the major advantages of the proposed method for the routine determination of these compounds in a large number of samples. PMID:20091158

  6. Auxin distribution and transport during embryonic pattern formation in wheat.

    PubMed

    Fischer-Iglesias, C; Sundberg, B; Neuhaus, G; Jones, A M

    2001-04-01

    Inhibitors of auxin polar transport disrupt normal embryogenesis and thus specific spatial auxin distribution due to auxin movement may be important in establishing embryonic pattern formation in plants. In the present study, the distribution of the photoaffinity labeling agent tritiated 5-azidoindole-3-acetic acid ([3H],5-N3IAA), an analog of indole-3-acetic acid (IAA), was visualized in zygotic wheat (Triticum aestivum L.) embryos grown in vitro and in planta, and used to deduce auxin transport pathways in these embryos. This study provides the first direct evidence that the distribution of auxin, here [3H],5-N3IAA, is heterogeneous and changes during embryo development. In particular, the shift from radial to bilateral symmetry was correlated with a redistribution of [3H],5-N3IAA in the embryo. Furthermore, in bilaterally symmetrical embryos, that is, embryos in the late transition stage or older, the localization of [3H],5-N3IAA was altered by N-1-naphthylphthalamic acid, a specific inhibitor of auxin polar transport. No significant effect was observed in radially symmetrical embryos, that is, globular embryos, or very early transition embryos. Thus, the shift from radial to bilateral symmetry is associated with the onset of active, directed auxin transport involved in auxin redistribution. A change in the distribution of [3H],5-N3IAA was also observed in morphologically abnormal embryos induced on media supplemented with auxin or auxin polar transport inhibitors. By means of a microscale technique, free IAA concentration was measured in in vitro- and in planta-grown embryos and was found to increase during development. Therefore, IAA may be synthesized or released from conjugates in bilaterally symmetrical embryos, although import from surrounding tissues cannot be excluded. PMID:11389754

  7. Retention, Molecular Evolution, and Expression Divergence of the Auxin/Indole Acetic Acid and Auxin Response Factor Gene Families in Brassica Rapa Shed Light on Their Evolution Patterns in Plants

    PubMed Central

    Huang, Zhinan; Duan, Weike; Song, Xiaoming; Tang, Jun; Wu, Peng; Zhang, Bei; Hou, Xilin

    2016-01-01

    Auxin/indole acetic acids (Aux/IAAs) and auxin response factors (ARFs), major components of the Aux signaling network, are involved in many developmental processes in plants. Investigating their evolution will provide new sight on the relationship between the molecular evolution of these genes and the increasing morphotypes of plants. We constructed comparative analyses of the retention, structure, expansion, and expression patterns of Aux/IAAs and ARFs in Brassica rapa and their evolution in eight other plant species, including algae, bryophytes, lycophytes, and angiosperms. All 33 of the ARFs, including 1 ARF-like (AL) (a type of ARF-like protein) and 53 Aux/IAAs, were identified in the B. rapa genome. The genes mainly diverged approximately 13 Ma. After the split, no Aux/IAA was completely lost, and they were more preferentially retained than ARFs. In land plants, compared with ARFs, which increased in stability, Aux/IAAs expanded more rapidly and were under more relaxed selective pressure. Moreover, BraIAAs were expressed in a more tissue-specific fashion than BraARFs and demonstrated functional diversification during gene duplication under different treatments, which enhanced the cooperative interaction of homologs to help plants adapt to complex environments. In addition, ALs existed widely and had a closer relationship with ARFs, suggesting that ALs might be the initial structure of ARFs. Our results suggest that the rapid expansion and preferential retention of Aux/IAAs are likely paralleled by the increasingly complex morphotypes in Brassicas and even in land plants. Meanwhile, the data support the hypothesis that the PB1 domain plays a key role in the origin of both Aux/IAAs and ARFs. PMID:26721260

  8. Retention, Molecular Evolution, and Expression Divergence of the Auxin/Indole Acetic Acid and Auxin Response Factor Gene Families in Brassica Rapa Shed Light on Their Evolution Patterns in Plants.

    PubMed

    Huang, Zhinan; Duan, Weike; Song, Xiaoming; Tang, Jun; Wu, Peng; Zhang, Bei; Hou, Xilin

    2016-02-01

    Auxin/indole acetic acids (Aux/IAAs) and auxin response factors (ARFs), major components of the Aux signaling network, are involved in many developmental processes in plants. Investigating their evolution will provide new sight on the relationship between the molecular evolution of these genes and the increasing morphotypes of plants. We constructed comparative analyses of the retention, structure, expansion, and expression patterns of Aux/IAAs and ARFs in Brassica rapa and their evolution in eight other plant species, including algae, bryophytes, lycophytes, and angiosperms. All 33 of the ARFs, including 1 ARF-like (AL) (a type of ARF-like protein) and 53 Aux/IAAs, were identified in the B. rapa genome. The genes mainly diverged approximately 13 Ma. After the split, no Aux/IAA was completely lost, and they were more preferentially retained than ARFs. In land plants, compared with ARFs, which increased in stability, Aux/IAAs expanded more rapidly and were under more relaxed selective pressure. Moreover, BraIAAs were expressed in a more tissue-specific fashion than BraARFs and demonstrated functional diversification during gene duplication under different treatments, which enhanced the cooperative interaction of homologs to help plants adapt to complex environments. In addition, ALs existed widely and had a closer relationship with ARFs, suggesting that ALs might be the initial structure of ARFs. Our results suggest that the rapid expansion and preferential retention of Aux/IAAs are likely paralleled by the increasingly complex morphotypes in Brassicas and even in land plants. Meanwhile, the data support the hypothesis that the PB1 domain plays a key role in the origin of both Aux/IAAs and ARFs. PMID:26721260

  9. Auxin carriers in membranes of lupin hypocotyls.

    PubMed

    Sabater, M; Sabater, F

    1986-01-01

    The pH-driven accumulation of [(3)H]indolyl-3-acetic acid (IAA) has been found to occur in membrane vesicles of lupin (Lupinus albus L.) hypocotyls. Most of this association of auxin with membranes is very sensitive to osmotic shock, high concentrations of permeable weak acids, incubation at 20° C for 20 min and to some ionophores. Long incubation times also depress the ability to accumulate radioactive IAA but this ability can be partially restored by a treatment that presumably reconstitutes the pH gradient across the membranes. Two specific inhibitors of auxin transport, N-1-naphtylphthalamic acid and 2,3,5-triiodobenzoic acid, stimulate net IAA uptake with an optimum at about 10(-6) M (pH 5.0). At least two auxin carriers appear to be present in the lupin membrane vesicles. An uptake carrier seems to be saturated at 10(-7) M IAA in the presence of N-1-naphtylphthalamic acid, but higher IAA concentrations are needed to saturate an efflux carrier. The uptake carrier also shows a high affinity for IAA and 2,4-dichlorophenoxyacetic acid and a low affinity for 1-naphthylacetic acid. PMID:24241734

  10. Dynamics of auxin movement in the gravistimulated leaf-sheath pulvinus of oat (Avena sativa)

    NASA Technical Reports Server (NTRS)

    Brock, Thomas C.; Kapen, E. H.; Ghosheh, Najati S.; Kaufman, Peter B.

    1991-01-01

    The role of auxin redistribution in the graviresponse of the leaf-sheath pulvinus of oat was evaluated using H-3-indole-3-acetic acid (H-3-IAA) preloaded into isolated pulvini. Results obtained reveal that, while lateral transport of auxin occurs following gravistimulation, it is not necessary for a graviresponse. Localized changes in tissue responsiveness or the conversion of conjugated hormone to free hormone may suffice to drive the graviresponse.

  11. Complete Genome Sequence of the Rhizobacterium Pseudomonas trivialis Strain IHBB745 with Multiple Plant Growth-Promoting Activities and Tolerance to Desiccation and Alkalinity.

    PubMed

    Gulati, Arvind; Swarnkar, Mohit Kumar; Vyas, Pratibha; Rahi, Praveen; Thakur, Rishu; Thakur, Namika; Singh, Anil Kumar

    2015-01-01

    The complete genome sequence of 6.45 Mb is reported here for Pseudomonas trivialis strain IHBB745 (MTCC 5336), which is an efficient, stress-tolerant, and broad-spectrum plant growth-promoting rhizobacterium. The gene-coding clusters predicted the genes for phosphate solubilization, siderophore production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, indole-3-acetic acid (IAA) production, and stress response. PMID:26337878

  12. Regulation of auxin, abscisic acid and salicylic acid levels by ascorbate application under heat stress in sensitive and tolerant maize leaves.

    PubMed

    Dinler, Burcu Seckin; Demir, Emel; Kompe, Yasemin Ozdener

    2014-12-01

    In the present study, the effect of ascorbic acid (5 mM) on some physiological parameters and three hormones (auxin, abscisic acid, salicylic acid) was determined under heat stress (40 °C) in maize tolerant cv. (MAY 69) and sensitive cv. SHEMAL (SH) at 0 h, 4 h and 8 h. Heat stress reduced total chlorophyll content (CHL), relative water content (RWC) and stomatal conductance (gs) in SH but did not lead to changes in MAY 69 at 4 h and 8 h. However, pretreatment with ascorbic acid increased (CHL), (RWC) and (gs) in SH under heat stress while it reduced MDA content significantly in both cv. We also observed that heat stress led to a reduction in SA level but increased ABA and IAA levels in SH, whereas it increased SA and IAA levels but did not change ABA level in MAY 69 at 4 h. Furthermore, in SH, ASC application under heat stress increased SA level and decreased IAA and ABA levels at 4 h, but it had no effect on SA and ABA at 8 h. PMID:25475985

  13. Insights into Auxin Signaling in Plant–Pathogen Interactions

    PubMed Central

    Fu, Jing; Wang, Shiping

    2011-01-01

    The phytohormone auxin has been known to be a regulator of plant growth and development ever since its discovery. Recent studies on plant–pathogen interactions identify auxin as a key character in pathogenesis and plant defense. Like plants, diverse pathogens possess the capacity to synthesize indole-3-acetic acid (IAA), the major form of auxin in plants. The emerging knowledge on auxin-signaling components, auxin metabolic processes, and indole-derived phytoalexins in plant responses to pathogen invasion has provided putative mechanisms of IAA in plant susceptibility and resistance to non-gall- or tumor-inducing pathogens. PMID:22639609

  14. Localize and identify the gravity sensing mechanism of plants

    NASA Technical Reports Server (NTRS)

    Bandurski, Robert S.

    1990-01-01

    The machinery by which a plant transduces the gravity stimulus into a growth response is localized and identified at the cellular level. The fact that a plant grows unequally on the lower side of a horizontally placed stem implies that there must be an asymmetric distribution of some of the chemical substances involved in the growth response. The three most likely chemicals to cause this growth were determined to be potassium, calcium, or the growth hormone, indole-3-acetic acid (IAA). IAA was chosen for this study and the results present a fairly complete understanding of the transduction of the gravity stimulus.

  15. Enzymic synthesis of indole-3-acetyl-1-O-beta-d-glucose. I. Partial purification and characterization of the enzyme from Zea mays

    NASA Technical Reports Server (NTRS)

    Leznicki, A. J.; Bandurski, R. S.

    1988-01-01

    The first enzyme-catalyzed reaction leading from indole-3-acetic acid (IAA) to the myo-inositol esters of IAA is the synthesis of indole-3-acetyl-1-O-beta-D-glucose from uridine-5'-diphosphoglucose (UDPG) and IAA. The reaction is catalyzed by the enzyme, UDPG-indol-3-ylacetyl glucosyl transferase (IAA-glucose-synthase). This work reports methods for the assay of the enzyme and for the extraction and partial purification of the enzyme from kernels of Zea mays sweet corn. The enzyme has an apparent molecular weight of 46,500 an isoelectric point of 5.5, and its pH optimum lies between 7.3 and 7.6. The enzyme is stable to storage at zero degrees but loses activity during column chromatographic procedures which can be restored only fractionally by addition of column eluates. The data suggest either multiple unknown cofactors or conformational changes leading to activity loss.

  16. Characterization of a tryptophan 2-monooxygenase gene from Puccinia graminis f. sp. tritici involved in auxin biosynthesis and rust pathogenicity.

    PubMed

    Yin, Chuntao; Park, Jeong-Jin; Gang, David R; Hulbert, Scot H

    2014-03-01

    The plant hormone indole-3-acetic acid (IAA) is best known as a regulator of plant growth and development but its production can also affect plant-microbe interactions. Microorganisms, including numerous plant-associated bacteria and several fungi, are also capable of producing IAA. The stem rust fungus Puccinia graminis f. sp. tritici induced wheat plants to accumulate auxin in infected leaf tissue. A gene (Pgt-IaaM) encoding a putative tryptophan 2-monooxygenase, which makes the auxin precursor indole-3-acetamide (IAM), was identified in the P. graminis f. sp. tritici genome and found to be expressed in haustoria cells in infected plant tissue. Transient silencing of the gene in infected wheat plants indicated that it was required for full pathogenicity. Expression of Pgt-IaaM in Arabidopsis caused a typical auxin expression phenotype and promoted susceptibility to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. PMID:24350783

  17. Gravitational effects on plant growth hormone concentration

    NASA Technical Reports Server (NTRS)

    Bandurski, R. S.; Schulze, A.

    1983-01-01

    Dolk's (1936) finding that more growth hormone diffuses from the lower side of a gravity-stimulated plant shoot than from the upper side is presently confirmed by means of both an isotope dilution assay and selected ion monitoring-gas chromatography-mass spectrometry, and it is established that the asymmetrically distributed hormone is indole-3-acetic acid (IAA). This is the first physicochemical demonstration that there is more IAA on the lower sides of a geostimulated plant shoot. It is also found that free IAA primarily occurs in the conductive vascular tissues of the shoot, while IAA esters predominate in the growing cortical cells. A highly sensitive gas chromatographic isotope dilution assay shows that the hormone asymmetry also occurs in the nonvascular tissue.

  18. Gravitational effects on plant growth hormone concentration

    NASA Astrophysics Data System (ADS)

    Bandurski, Robert S.; Schulze, Aga

    Numerous studies, particularly those of H. Dolk in the 1930's, established by means of bio-assay, that more growth hormone diffused from the lower, than from the upper side of a gravity-stimulated plant shoot. Now, using an isotope dilution assay, with 4,5,6,7 tetradeutero indole-3-acetic acid as internal standard, and selected ion monitoring-gas chromatography-mass spectrometry as the method of determination, we have confirmed Dolk's finding and established that the asymmetrically distributed hormone is, in fact, indole-3-acetic acid (IAA). This is the first physico-chemical demonstration that there is more free IAA on the lower sides of a geo-stimulated plant shoot. We have also shown that free IAA occurs primarily in the conductive vascular tissues of the shoot, whereas IAA esters predominate in the growing cortical cells. Now, using an especially sensitive gas chromatographic isotope dilution assay we have found that the hormone asymmetry also occurs in the non-vascular tissue. Currently, efforts are directed to developing isotope dilution assays, with picogram sensitivity, to determine how this asymmetry of IAA distribution is attained so as to better understand how the plant perceives the geo-stimulus.

  19. Red light-regulated growth. I. Changes in the abundance of indoleacetic acid and a 22-kilodalton auxin-binding protein in the maize mesocotyl

    NASA Technical Reports Server (NTRS)

    Jones, A. M.; Cochran, D. S.; Lamerson, P. M.; Evans, M. L.; Cohen, J. D.

    1991-01-01

    We examined the changes in the levels of indoleacetic acid (IAA), IAA esters, and a 22-kilodalton subunit auxin-binding protein (ABP1) in apical mesocotyl tissue of maize (Zea mays L.) during continuous red light (R) irradiation. These changes were compared with the kinetics of R-induced growth inhibition in the same tissue. Upon the onset of continuous irradiation, growth decreased in a continuous manner following a brief lag period. The decrease in growth continued for 5 hours, then remained constant at 25% of the dark rate. The abundance of ABP1 and the level of free IAA both decreased in the mesocotyl. Only the kinetics of the decrease in IAA within the apical mesocotyl correlated with the initial change in growth, although growth continued to decrease even after IAA content reached its final level, 50% of the dark control. This decrease in IAA within the mesocotyl probably occurs primarily by a change in its transport within the shoot since auxin applied as a pulse move basipetally in R-irradiated tissue at the same rate but with half the area as dark control tissue. In situ localization of auxin in etiolated maize shoots revealed that R-irradiated shoots contained less auxin in the epidermis than the dark controls. Irradiated mesocotyl grew 50% less than the dark controls even when incubated in an optimal level of auxin. However, irradiated and dark tissue contained essentially the same amount of radioactivity after incubation in [14C]IAA indicating that the light treatment does not affect the uptake into the tissue through the cut end, although it is possible that a small subset of cells within the mesocotyl is affected. These observations support the hypothesis that R causes a decrease in the level of auxin in epidermal cells of the mesocotyl, consequently constraining the growth of the entire mesocotyl.

  20. Development of a semipurified test diet for determining amino acid requirements of Florida pompano Trachinotus carolinus reared under low-salinity conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two trials were conducted to develop a semipurified test diet for determining indispensable amino acid (IAA) requirements for Florida pompano Trachinotus carolinus. The objective of the first trial was to evaluate casein and corn gluten meal as principal intact protein sources, and the ability of F...

  1. Basipetal auxin transport is required for gravitropism in roots of Arabidopsis

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  2. Low-Fluence Red Light Increases the Transport and Biosynthesis of Auxin1[C][W][OA

    PubMed Central

    Liu, Xing; Cohen, Jerry D.; Gardner, Gary

    2011-01-01

    In plants, light is an important environmental signal that induces photomorphogenesis and interacts with endogenous signals, including hormones. We found that light increased polar auxin transport in dark-grown Arabidopsis (Arabidopsis thaliana) and tomato (Solanum lycopersicum) hypocotyls. In tomato, this increase was induced by low-fluence red or blue light followed by 1 d of darkness. It was reduced in phyA, phyB1, and phyB2 tomato mutants and was reversed by far-red light applied immediately after the red or blue light exposure, suggesting that phytochrome is involved in this response. We further found that the free indole-3-acetic acid (IAA) level in hypocotyl regions below the hook was increased by red light, while the level of conjugated IAA was unchanged. Analysis of IAA synthesized from [13C]indole or [13C]tryptophan (Trp) revealed that both Trp-dependent and Trp-independent IAA biosynthesis were increased by low-fluence red light in the top section (meristem, cotyledons, and hook), and the Trp-independent pathway appears to become the primary route for IAA biosynthesis after red light exposure. IAA biosynthesis in tissues below the top section was not affected by red light, suggesting that the increase of free IAA in this region was due to increased transport of IAA from above. Our study provides a comprehensive view of light effects on the transport and biosynthesis of IAA, showing that red light increases both IAA biosynthesis in the top section and polar auxin transport in hypocotyls, leading to unchanged free IAA levels in the top section and increased free IAA levels in the lower hypocotyl regions. PMID:21807888

  3. Rapid auxin-mediated changes in the proteome of the epidermal cells in rye coleoptiles: Implications for the initiation of growth

    PubMed Central

    Deng, Z.; Xu, S.; Chalkley, R. J.; Oses-Prieto, J. A.; Burlingame, A. L.; Wang, Z.-Y.; Kutschera, U.

    2011-01-01

    In axial organs of juvenile plants, the phytohormone auxin (indole-3-acetic acid, IAA) rapidly allows cell wall loosening and hence promotes turgor-driven elongation. In this study, we used rye (Secale cereale) coleoptile sections to investigate possible effects of IAA on the proteome of cells. In a first set of experiments, we document that IAA causes organ elongation via promotion of expansion of the rigid outer wall of the outer epidermis. A quantitative comparison of the proteome (membrane-associated proteins), using two-dimensional difference gel electrophoresis (2-D DIGE), revealed that, within 2 h of auxin treatment, at least 16 protein spots were up- or down-regulated by IAA. These proteins were identified using reverse-phase liquid chromatography electrospray tandem mass spectrometry. Four of these proteins were detected in the growth-controlling outer epidermis and were further analysed. One epidermal polypeptide, a small Ras-related GTP-binding protein, was rapidly down-regulated by IAA (after 0.5 h of incubation) by −35% compared to the control. Concomitantly, a subunit of the 26S proteasome was up-regulated by IAA (+30% within 1 h). In addition, this protein displayed IAA-mediated post-translational modification. The implications of these rapid auxin effects with respect to signal transduction and IAA-mediated secretion of glycoproteins (osmiophilic nano-particles) into the growth-controlling outer epidermal wall are discussed. PMID:22117532

  4. Hydrolases of the ILR1-like family of Arabidopsis thaliana modulate auxin response by regulating auxin homeostasis in the endoplasmic reticulum

    PubMed Central

    Sanchez Carranza, Ana Paula; Singh, Aparajita; Steinberger, Karoline; Panigrahi, Kishore; Palme, Klaus; Dovzhenko, Alexander; Dal Bosco, Cristina

    2016-01-01

    Amide-linked conjugates of indole-3-acetic acid (IAA) have been identified in most plant species. They function in storage, inactivation or inhibition of the growth regulator auxin. We investigated how the major known endogenous amide-linked IAA conjugates with auxin-like activity act in auxin signaling and what role ILR1-like proteins play in this process in Arabidopsis. We used a genetically encoded auxin sensor to show that IAA-Leu, IAA-Ala and IAA-Phe act through the TIR1-dependent signaling pathway. Furthermore, by using the sensor as a free IAA reporter, we followed conjugate hydrolysis mediated by ILR1, ILL2 and IAR3 in plant cells and correlated the activity of the hydrolases with a modulation of auxin response. The conjugate preferences that we observed are in agreement with available in vitro data for ILR1. Moreover, we identified IAA-Leu as an additional substrate for IAR3 and showed that ILL2 has a more moderate kinetic performance than observed in vitro. Finally, we proved that IAR3, ILL2 and ILR1 reside in the endoplasmic reticulum, indicating that in this compartment the hydrolases regulate the rates of amido-IAA hydrolysis which results in activation of auxin signaling. PMID:27063913

  5. Hydrolases of the ILR1-like family of Arabidopsis thaliana modulate auxin response by regulating auxin homeostasis in the endoplasmic reticulum.

    PubMed

    Sanchez Carranza, Ana Paula; Singh, Aparajita; Steinberger, Karoline; Panigrahi, Kishore; Palme, Klaus; Dovzhenko, Alexander; Dal Bosco, Cristina

    2016-01-01

    Amide-linked conjugates of indole-3-acetic acid (IAA) have been identified in most plant species. They function in storage, inactivation or inhibition of the growth regulator auxin. We investigated how the major known endogenous amide-linked IAA conjugates with auxin-like activity act in auxin signaling and what role ILR1-like proteins play in this process in Arabidopsis. We used a genetically encoded auxin sensor to show that IAA-Leu, IAA-Ala and IAA-Phe act through the TIR1-dependent signaling pathway. Furthermore, by using the sensor as a free IAA reporter, we followed conjugate hydrolysis mediated by ILR1, ILL2 and IAR3 in plant cells and correlated the activity of the hydrolases with a modulation of auxin response. The conjugate preferences that we observed are in agreement with available in vitro data for ILR1. Moreover, we identified IAA-Leu as an additional substrate for IAR3 and showed that ILL2 has a more moderate kinetic performance than observed in vitro. Finally, we proved that IAR3, ILL2 and ILR1 reside in the endoplasmic reticulum, indicating that in this compartment the hydrolases regulate the rates of amido-IAA hydrolysis which results in activation of auxin signaling. PMID:27063913

  6. Auxin production by the plant trypanosomatid Phytomonas serpens and auxin homoeostasis in infected tomato fruits.

    PubMed

    Ienne, Susan; Freschi, Luciano; Vidotto, Vanessa F; De Souza, Tiago A; Purgatto, Eduardo; Zingales, Bianca

    2014-09-01

    Previously we have characterized the complete gene encoding a pyruvate decarboxylase (PDC)/indolepyruvate decarboxylase (IPDC) of Phytomonas serpens, a trypanosomatid highly abundant in tomato fruits. Phylogenetic analyses indicated that the clade that contains the trypanosomatid protein behaves as a sister group of IPDCs of γ-proteobacteria. Since IPDCs are key enzymes in the biosynthesis of the plant hormone indole-3-acetic acid (IAA), the ability for IAA production by P. serpens was investigated. Similar to many microorganisms, the production of IAA and related indolic compounds, quantified by high performance liquid chromatography, increased in P. serpens media in response to amounts of tryptophan. The auxin functionality was confirmed in the hypocotyl elongation assay. In tomato fruits inoculated with P. serpens the concentration of free IAA had no significant variation, whereas increased levels of IAA-amide and IAA-ester conjugates were observed. The data suggest that the auxin produced by the flagellate is converted to IAA conjugates, keeping unaltered the concentration of free IAA. Ethanol also accumulated in P. serpens-conditioned media, as the result of a PDC activity. In the article we discuss the hypothesis of the bifunctionality of P. serpens PDC/IPDC and provide a three-dimensional model of the enzyme. PMID:24805281

  7. The branching gene RAMOSUS1 mediates interactions among two novel signals and auxin in pea.

    PubMed

    Foo, Eloise; Bullier, Erika; Goussot, Magali; Foucher, Fabrice; Rameau, Catherine; Beveridge, Christine Anne

    2005-02-01

    In Pisum sativum, the RAMOSUS genes RMS1, RMS2, and RMS5 regulate shoot branching via physiologically defined mobile signals. RMS1 is most likely a carotenoid cleavage enzyme and acts with RMS5 to control levels of an as yet unidentified mobile branching inhibitor required for auxin inhibition of branching. Our work provides molecular, genetic, and physiological evidence that RMS1 plays a central role in a shoot-to-root-to-shoot feedback system that regulates shoot branching in pea. Indole-3-acetic acid (IAA) positively regulates RMS1 transcript level, a potentially important mechanism for regulation of shoot branching by IAA. In addition, RMS1 transcript levels are dramatically elevated in rms3, rms4, and rms5 plants, which do not contain elevated IAA levels. This degree of upregulation of RMS1 expression cannot be achieved in wild-type plants by exogenous IAA application. Grafting studies indicate that an IAA-independent mobile feedback signal contributes to the elevated RMS1 transcript levels in rms4 plants. Therefore, the long-distance signaling network controlling branching in pea involves IAA, the RMS1 inhibitor, and an IAA-independent feedback signal. Consistent with physiological studies that predict an interaction between RMS2 and RMS1, rms2 mutations appear to disrupt this IAA-independent regulation of RMS1 expression. PMID:15659639

  8. Evidence that the mature leaves contribute auxin to the immature tissues of pea (Pisum sativum L.).

    PubMed

    Jager, Corinne E; Symons, Gregory M; Glancy, Naomi E; Reid, James B; Ross, John J

    2007-07-01

    In plants such as the garden pea (Pisum sativum L.), it is widely thought that the auxin indole-3-acetic acid (IAA) is synthesised mainly in the immature tissues of the apical bud and then transported basipetally to other parts of the plant. Consistent with this belief are results showing that removal of the apical bud markedly reduces the IAA content in the stem. However, it has also been suggested that the mature leaves may synthesise substantial amounts of IAA, which enters the basipetal transport stream after being transported to the shoot apex in the phloem (Cambridge and Morris in Planta 99:583-588, 1996). To examine this theory, we defoliated pea plants and measured the effect on IAA content in the remaining shoot tissues. IAA levels were reduced in the internodes, and to a lesser extent in the apical bud, after defoliation, suggesting that mature leaves are indeed an important source of auxin for the shoot. Consistent with this idea, we have demonstrated that mature, fully expanded leaves are capable of de novo IAA synthesis. Furthermore, we report evidence for the presence of IAA in the phloem sap of pea. Together these results support those of Cambridge and Morris, suggesting that mature leaves are a source of the IAA in the basipetal transport stream. PMID:17308928

  9. The mechanism by which an asymmetric distribution of plant growth hormone is attained

    NASA Astrophysics Data System (ADS)

    Bandurski, Robert S.; Schulze, Aga; Jensen, Philip; Desrosiers, Mark; Epel, Bernard; Kowalczyk, Stanley

    Zea mays (sweet corn) seedlings attain an asymmetric distribution of the growth hormone indole-3-acetic acid (IAA) within 3 minutes following a gravity stimulus. Both free and esterified IAA (that is total IAA) accumulate to a greater extent in the lower half of the mesocotyl cortex of a horizontally placed seedling than in the upper half. Thus, changes in the ratio of free IAA to ester IAA cannot account for the asymmetric distribution. Our studies demonstrate there is no de novo synthesis of IAA in young seedlings. We conclude that asymmetric IAA distribution is attained by a gravity-induced, potential-regulated gating of the movement of IAA from kernel to shoot and from stele to cortex. As a working theory, which we call the Potential Gating Theory, we propose that perturbation of the plant's bioelectric field, induced by gravity, causes opening and closing of transport channels in the plasmodesmata connecting the vascular stele to the surrounding cortical tissues. This results in asymmetric growth hormone distribution which results in the asymmetric growth characteristic of the gravitropic response.

  10. MIPAS IMK/IAA CFC-11 (CCl3F) and CFC-12 (CCl2F2) measurements: accuracy, precision and long-term stability

    NASA Astrophysics Data System (ADS)

    Eckert, E.; Laeng, A.; Lossow, S.; Kellmann, S.; Stiller, G.; von Clarmann, T.; Glatthor, N.; Höpfner, M.; Kiefer, M.; Oelhaf, H.; Orphal, J.; Funke, B.; Grabowski, U.; Haenel, F.; Linden, A.; Wetzel, G.; Woiwode, W.; Bernath, P. F.; Boone, C.; Dutton, G. S.; Elkins, J. W.; Engel, A.; Gille, J. C.; Kolonjari, F.; Sugita, T.; Toon, G. C.; Walker, K. A.

    2016-07-01

    Profiles of CFC-11 (CCl3F) and CFC-12 (CCl2F2) of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the European satellite Envisat have been retrieved from versions MIPAS/4.61 to MIPAS/4.62 and MIPAS/5.02 to MIPAS/5.06 level-1b data using the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK) and Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Astrofísica de Andalucía (IAA). These profiles have been compared to measurements taken by the balloon-borne cryosampler, Mark IV (MkIV) and MIPAS-Balloon (MIPAS-B), the airborne MIPAS-STRatospheric aircraft (MIPAS-STR), the satellite-borne Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) and the High Resolution Dynamic Limb Sounder (HIRDLS), as well as the ground-based Halocarbon and other Atmospheric Trace Species (HATS) network for the reduced spectral resolution period (RR: January 2005-April 2012) of MIPAS. ACE-FTS, MkIV and HATS also provide measurements during the high spectral resolution period (full resolution, FR: July 2002-March 2004) and were used to validate MIPAS CFC-11 and CFC-12 products during that time, as well as profiles from the Improved Limb Atmospheric Spectrometer, ILAS-II. In general, we find that MIPAS shows slightly higher values for CFC-11 at the lower end of the profiles (below ˜ 15 km) and in a comparison of HATS ground-based data and MIPAS measurements at 3 km below the tropopause. Differences range from approximately 10 to 50 pptv ( ˜ 5-20 %) during the RR period. In general, differences are slightly smaller for the FR period. An indication of a slight high bias at the lower end of the profile exists for CFC-12 as well, but this bias is far less pronounced than for CFC-11 and is not as obvious in the relative differences between MIPAS and any of the comparison instruments. Differences at the lower end of the profile (below ˜ 15 km) and in

  11. MIPAS IMK/IAA CFC-11 (CCl3F) and CFC-12 (CCl2F2) measurements: accuracy, precision and long-term stability

    NASA Astrophysics Data System (ADS)

    Eckert, E.; Laeng, A.; Lossow, S.; Kellmann, S.; Stiller, G.; von Clarmann, T.; Glatthor, N.; Höpfner, M.; Kiefer, M.; Oelhaf, H.; Orphal, J.; Funke, B.; Grabowski, U.; Haenel, F.; Linden, A.; Wetzel, G.; Woiwode, W.; Bernath, P. F.; Boone, C.; Dutton, G. S.; Elkins, J. W.; Engel, A.; Gille, J. C.; Kolonjari, F.; Sugita, T.; Toon, G. C.; Walker, K. A.

    2015-07-01

    Profiles of CFC-11 (CCl3F) and CFC-12 (CCl2F2) of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) abord the European satellite Envisat have been retrieved from versions MIPAS/4.61-MIPAS/4.62 and MIPAS/5.02-MIPAS/5.06 level-1b data using the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK) and Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Astrofísica de Andalucía (IAA). These profiles have been compared to measurements taken by the balloon borne Cryosampler, Mark IV (MkIV) and MIPAS-Balloon (MIPAS-B), the airborne MIPAS stratospheric aircraft (MIPAS-STR), the satellite borne Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) and the High Resolution Dynamic Limb Sounder (HIRDLS) as well as the ground based Halocarbon and other Atmospheric Trace Species (HATS) network for the reduced spectral resolution period (RR: January 2005-April 2012) of MIPAS Envisat. ACE-FTS, MkIV and HATS also provide measurements during the high spectral resolution period (FR: July 2002-March 2004) and were used to validate MIPAS Envisat CFC-11 and CFC-12 products during that time, as well as ILAS-II profiles. In general, we find that MIPAS Envisat shows slightly higher values for CFC-11 at the lower end of the profiles (below ~ 15 km) and in a comparison of HATS ground-based data and MIPAS Envisat measurements at 3 km below the tropopause. Differences range from approximately 10-50 pptv (~ 5-20 %) during the RR period. In general, differences are slightly smaller for the FR period. An indication of a slight high-bias at the lower end of the profile exists for CFC-12 as well, but this bias is far less pronounced than for CFC-11, so that differences at the lower end of the profile (below ~ 15 km) and in the comparison of HATS and MIPAS Envisat measurements taken at 3 km below the tropopause mainly stay within 10-50 pptv (~ 2-10 %) for the RR and

  12. Indoleacetic Acid biosynthesis in Avena coleoptile tips and excised bean shoots.

    PubMed

    Black, R C; Hamilton, R H

    1971-11-01

    Avena coleoptiles did not elongate when incubated with tryptophan under sterile conditions. Indole, anthranilic acid, and tryptamine promoted elongation. Under the same conditions, the tissue converted tryptophan-(14)C to IAA-(14)C. More IAA-(14)C was produced from indole-(14)C than from tryptophan-(14)C; however, the free tryptophan content of the tissue was also greatly increased by the indole treatment. Tryptophan-(14)C was readily taken up by the tissue but was mainly incorporated into protein and did not increase the free tryptophan level. When bean shoots were labeled with tryptophan-(14)C or indole-(14)C, the label incorporation into IAA-(14)C was very nearly the same. In this tissue the free tryptophan level in the tryptophan-(14)C and indole-(14)C treatments was also about equal. These results suggest that failure of exogenously supplied tryptophan to promote the elongation of Avena coleoptiles is a result of its predominant incorporation into protein and consequent unavailability for conversion to IAA. PMID:16657844

  13. 5'-Azido-[3,6-3H2]-1-napthylphthalamic acid, a photoactivatable probe for naphthylphthalamic acid receptor proteins from higher plants: identification of a 23-kDa protein from maize coleoptile plasma membranes.

    PubMed Central

    Zettl, R; Feldwisch, J; Boland, W; Schell, J; Palme, K

    1992-01-01

    1-Naphthylphthalamic acid (NPA) is a specific inhibitor of polar auxin transport that blocks carrier-mediated auxin efflux from plant cells. To allow identification of the NPA receptor thought to be part of the auxin efflux carrier, we have synthesized a tritiated, photolabile NPA analogue, 5'-azido-[3,6-3H2]NPA ([3H2]N3NPA). This analogue was used to identify NPA-binding proteins in fractions highly enriched for plasma membrane vesicles isolated from maize coleoptiles (Zea mays L.). Competition studies showed that binding of [3H2]N3NPA to maize plasma membrane vesicles was blocked by nonradioactive NPA but not by benzoic acid. After incubation of plasma membrane vesicles with [3H2]N3NPA and exposure to UV light, we observed specific photoaffinity labeling of a protein with an apparent molecular mass of 23 kDa. Pretreatment of the plasma membrane vesicles with indole-3-acetic acid or with the auxin-transport inhibitors NPA and 2,3,5-triiodobenzoic acid strongly reduced specific labeling of this protein. This 23-kDa protein was also labeled by addition of 5-azido-[7-3H]indole-3-acetic acid to plasma membranes prior to exposure to UV light. The 23-kDa protein was solubilized from plasma membranes by 1% Triton X-100. The possibility that this 23-kDa polypeptide is part of the auxin efflux carrier system is discussed. Images PMID:11607252

  14. The Pseudomonas syringae Type III Effector AvrRpt2 Promotes Pathogen Virulence via Stimulating Arabidopsis Auxin/Indole Acetic Acid Protein Turnover1[C][W][OA

    PubMed Central

    Cui, Fuhao; Wu, Shujing; Sun, Wenxian; Coaker, Gitta; Kunkel, Barbara; He, Ping; Shan, Libo

    2013-01-01

    To accomplish successful infection, pathogens deploy complex strategies to interfere with host defense systems and subvert host physiology to favor pathogen survival and multiplication. Modulation of plant auxin physiology and signaling is emerging as a common virulence strategy for phytobacteria to cause diseases. However, the underlying mechanisms remain largely elusive. We have previously shown that the Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis (Arabidopsis thaliana) auxin physiology. Here, we report that AvrRpt2 promotes auxin response by stimulating the turnover of auxin/indole acetic acid (Aux/IAA) proteins, the key negative regulators in auxin signaling. AvrRpt2 acts additively with auxin to stimulate Aux/IAA turnover, suggesting distinct, yet proteasome-dependent, mechanisms operated by AvrRpt2 and auxin to control Aux/IAA stability. Cysteine protease activity is required for AvrRpt2-stimulated auxin signaling and Aux/IAA degradation. Importantly, transgenic plants expressing the dominant axr2-1 mutation recalcitrant to AvrRpt2-mediated degradation ameliorated the virulence functions of AvrRpt2 but did not alter the avirulent function mediated by the corresponding RPS2 resistance protein. Thus, promoting auxin response via modulating the stability of the key transcription repressors Aux/IAA is a mechanism used by the bacterial type III effector AvrRpt2 to promote pathogenicity. PMID:23632856

  15. Novel use of positively charged nylon transfer membranes for trapping indoleacetic acid or other small anions during efflux from plant tissues

    NASA Technical Reports Server (NTRS)

    Evans, M. L.; Hangarter, R. P.

    1993-01-01

    Positively charged nylon blotting membranes were used as an anion binding medium to trap [14C]indoleactic acid (IAA) as it exited cells at the basal ends of Coleus blumei L. stem and Zea mays L. coleoptile segments. Autoradiography was used to visualize where the [14C] that moved out of the cut ends was localized on the nylon membrane. Diffusion of [14C]IAA from the initial point of contact with the nylon membrane was minimal. Comparison of the autoradiograms with anatomical tissue prints of the cut ends of the segments was used to determine what tissues participate in IAA movement. The results of these initial studies were consistent with other reports suggesting that [14C]IAA movement was primarily associated with vascular tissues in both C. blumei stems and corn coleoptiles, but the resolution was not sufficient to identify which vascular tissues were involved in IAA transport. With further refinements, this technique could also be used for studying the movement of other small charged molecules through plant tissues.

  16. Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize

    NASA Technical Reports Server (NTRS)

    Evans, M. L.; Mulkey, T. J.

    1984-01-01

    In order to test the idea that auxin action on root growth may be mediated by H(+) movement, the correlation of auxin action on growth and H(+) movement in roots was examined along with changes in H(+) efflux patterns associated with the asymmetric growth which occurs during gravitropism. The effects of indoleacetic acid (IAA) and abscisic acid (AbA) on growth, H(+) secretion, and gravitropism in roots were compared. Results show a close correlation existent between H(+) efflux and growth in maize roots. In intact roots there is strong H(+) efflux from the elongation zone. Growth-promoting concentrations of IAA stimulate H(+) efflux. During gravitropism the H(+) efflux from the elongation zone becomes asymmetric; the evidence indicates that auxin redistribution contributes to the development of acid efflux asymmetry. That AbA stimulates root growth is reflected in its ability to stimulate H(+) efflux from apical root segments.

  17. Monohaloacetic acid drinking water disinfection by-products inhibit follicle growth and steroidogenesis in mouse ovarian antral follicles in vitro.

    PubMed

    Jeong, Clara H; Gao, Liying; Dettro, Tyler; Wagner, Elizabeth D; Ricke, William A; Plewa, Michael J; Flaws, Jodi A

    2016-07-01

    Water disinfection greatly reduced the incidence of waterborne diseases, but the reaction between disinfectants and natural organic matter in water leads to the formation of drinking water disinfection by-products (DBPs). DBPs have been shown to be toxic, but their effects on the ovary are not well defined. This study tested the hypothesis that monohalogenated DBPs (chloroacetic acid, CAA; bromoacetic acid, BAA; iodoacetic acid, IAA) inhibit antral follicle growth and steroidogenesis in mouse ovarian follicles. Antral follicles were isolated and cultured with either vehicle or DBPs (0.25-1.00mM of CAA; 2-15μM of BAA or IAA) for 48 and 96h. Follicle growth was measured every 24h and the media were analyzed for estradiol levels at 96h. Exposure to DBPs significantly inhibited antral follicle growth and reduced estradiol levels compared to controls. These data demonstrate that DBP exposure caused ovarian toxicity in vitro. PMID:27151372

  18. The role of hormone transport and metabolism in apical dominance in oats

    NASA Technical Reports Server (NTRS)

    Harrison, M. A.; Kaufman, P. B.

    1984-01-01

    14C-benzyladenine (BA) and 14C-indole-3-acetic acid (IAA) were used to study hormone transport to the tiller bud and hormone catabolism in excised oat stem segments. Acropetal BA transport was greatest from upright stem segments to tiller buds suppressed by apical dominance. IAA, abscisic acid (ABA), and C2H4 inhibited BA transport to the tiller bud. IAA transport to the tiller bud site was inhibited by BA, C2H4, or after gravistimulation, which affected BA transport to a lesser extent than IAA transport. Multiple peaks of radioactivity were observed in 14C-BA- or 14C-IAA-treated stem segments after 9 h of transport. IAA, ABA, and C2H4 promoted BA catabolism. Auxin, ABA, and C2H4 may inhibit tiller bud release by inhibiting cytokinin transport to the tiller bud and by promoting cytokinin catabolism. Gravistimulation may promote tiller release by inhibiting IAA transport to the tiller bud and allowing cytokinins to accumulate there preferentially.

  19. Local auxin metabolism regulates environment-induced hypocotyl elongation.

    PubMed

    Zheng, Zuyu; Guo, Yongxia; Novák, Ondřej; Chen, William; Ljung, Karin; Noel, Joseph P; Chory, Joanne

    2016-01-01

    A hallmark of plants is their adaptability of size and form in response to widely fluctuating environments. The metabolism and redistribution of the phytohormone auxin play pivotal roles in establishing active auxin gradients and resulting cellular differentiation. In Arabidopsis thaliana, cotyledons and leaves synthesize indole-3-acetic acid (IAA) from tryptophan through indole-3-pyruvic acid (3-IPA) in response to vegetational shade. This newly synthesized auxin moves to the hypocotyl where it induces elongation of hypocotyl cells. Here we show that loss of function of VAS2 (IAA-amido synthetase Gretchen Hagen 3 (GH3).17) leads to increases in free IAA at the expense of IAA-Glu (IAA-glutamate) in the hypocotyl epidermis. This active IAA elicits shade- and high temperature-induced hypocotyl elongation largely independently of 3-IPA-mediated IAA biosynthesis in cotyledons. Our results reveal an unexpected capacity of local auxin metabolism to modulate the homeostasis and spatial distribution of free auxin in specialized organs such as hypocotyls in response to shade and high temperature. PMID:27249562

  20. Polar Transport Related to Mobilization of Plant Constituents

    PubMed Central

    Zaerr, J. B.; Mitchell, J. W.

    1967-01-01

    Indole-3-acetic acid (IAA), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), sucrose, and mannitol, were tested for polar transport through 5-mm hypocotyl segments of bean (Phaseolus vulgaris var. Pinto) seedlings. All 4 compounds were transported in a polar direction. Autoradiographs of segments through which 14C-labeled compounds were transported indicated areas of 14C concentration near the morphological base of segments. There was a direct correlation of IAA transport with the ability to initiate roots as well as with the degree of 14C accumulation in the morphological base of segments. Unlabeled IAA in lanolin applied to segments appeared to reduce transport of IAA-14C through those segments when measured by the accumulation of 14C in a receiver-block of agar, caused an increase in 14C accumulation in the region to which the unlabeled IAA was applied, and also caused a decrease in accumulation of 14C at the morphological base of upright segments. Histological studies showed that IAA accelerated cell division and the formation of root primordia particularly at the basal ends, and that these responses sometimes occurred at the expense of cell proliferation at the apical ends of segments. The data presented support the hypothesis that polar movement of IAA, and other endogenous and exogenous substances, in isolated stem segments was controlled by mobilization and utilization of plant constituents at the growth centers. Images PMID:16656584

  1. Auxin and Tryptophan Homeostasis Are Facilitated by the ISS1/VAS1 Aromatic Aminotransferase in Arabidopsis

    PubMed Central

    Pieck, Michael; Yuan, Youxi; Godfrey, Jason; Fisher, Christopher; Zolj, Sanda; Vaughan, Dylan; Thomas, Nicholas; Wu, Connie; Ramos, Julian; Lee, Norman; Normanly, Jennifer; Celenza, John L.

    2015-01-01

    Indole-3-acetic acid (IAA) plays a critical role in regulating numerous aspects of plant growth and development. While there is much genetic support for tryptophan-dependent (Trp-D) IAA synthesis pathways, there is little genetic evidence for tryptophan-independent (Trp-I) IAA synthesis pathways. Using Arabidopsis, we identified two mutant alleles of ISS1 (Indole Severe Sensitive) that display indole-dependent IAA overproduction phenotypes including leaf epinasty and adventitious rooting. Stable isotope labeling showed that iss1, but not WT, uses primarily Trp-I IAA synthesis when grown on indole-supplemented medium. In contrast, both iss1 and WT use primarily Trp-D IAA synthesis when grown on unsupplemented medium. iss1 seedlings produce 8-fold higher levels of IAA when grown on indole and surprisingly have a 174-fold increase in Trp. These findings indicate that the iss1 mutant’s increase in Trp-I IAA synthesis is due to a loss of Trp catabolism. ISS1 was identified as At1g80360, a predicted aromatic aminotransferase, and in vitro and in vivo analysis confirmed this activity. At1g80360 was previously shown to primarily carry out the conversion of indole-3-pyruvic acid to Trp as an IAA homeostatic mechanism in young seedlings. Our results suggest that in addition to this activity, in more mature plants ISS1 has a role in Trp catabolism and possibly in the metabolism of other aromatic amino acids. We postulate that this loss of Trp catabolism impacts the use of Trp-D and/or Trp-I IAA synthesis pathways. PMID:26163189

  2. Non-invasive quantification of endogenous root auxin transport using an integrated flux microsensor technique.

    PubMed

    McLamore, Eric S; Diggs, Alfred; Calvo Marzal, Percy; Shi, Jin; Blakeslee, Joshua J; Peer, Wendy A; Murphy, Angus S; Porterfield, D Marshall

    2010-09-01

    Indole-3-acetic acid (IAA) is a primary phytohormone that regulates multiple aspects of plant development. Because polar transport of IAA is an essential determinant of organogenesis and dynamic tropic growth, methods to monitor IAA movement in vivo are in demand. A self-referencing electrochemical microsensor was optimized to non-invasively measure endogenous IAA flux near the surface of Zea mays roots without the addition of exogenous IAA. Enhanced sensor surface modification, decoupling of acquired signals, and integrated flux analyses were combined to provide direct, real time quantification of endogenous IAA movement in B73 maize inbred and brachytic2 (br2) auxin transport mutant roots. BR2 is localized in epidermal and hypodermal tissues at the root apex. br2 roots exhibit reduced shootward IAA transport at the root apex in radiotracer experiments and reduced gravitropic growth. IAA flux data indicates that maximal transport occurs in the distal elongation zone of maize roots, and net transport in/out of br2 roots was decreased compared to B73. Integration of short term real time flux data in this zone revealed oscillatory patterns, with B73 exhibiting shorter oscillatory periods and greater amplitude than br2. IAA efflux and influx were inhibited using 1-N-naphthylphthalamic acid (NPA), and 2-naphthoxyacetic acid (NOA), respectively. A simple harmonic oscillation model of these data produced a correlation between modeled and measured values of 0.70 for B73 and 0.69 for br2. These results indicate that this technique is useful for real-time IAA transport monitoring in surface tissues and that this approach can be performed simultaneously with current live imaging techniques. PMID:20626658

  3. Auxin-induced leaf blade expansion in Arabidopsis requires both wounding and detachment

    PubMed Central

    Keller, Christopher P.; Grundstad, Morgan L.; Evanoff, Michael A.; Keith, Jeremy D.; Lentz, Derek S.; Wagner, Samuel L.; Culler, Angela H.; Cohen, Jerry D.

    2011-01-01

    Elevation of leaf auxin (indole-3-acetic acid; IAA) levels in intact plants has been consistently found to inhibit leaf expansion whereas excised leaf strips grow faster when treated with IAA. Here we test two hypothetical explanations for this difference in growth sensitivity to IAA by expanding leaf tissues in vivo versus in vitro. We asked if, in Arabidopsis, IAA-induced growth of excised leaf strips results from the wounding required to excise tissue and/or results from detachment from the plant and thus loss of some shoot or root derived growth controlling factors. We tested the effect of a range of exogenous IAA concentrations on the growth of intact attached, wounded attached, detached intact, detached wounded as well as excised leaf strips. After 24 h, the growth of intact attached, wounded attached, and detached intact leaves was inhibited by IAA concentrations as little as 1 µM in some experiments. Growth of detached wounded leaves and leaf strips was induced by IAA concentrations as low as 10 µM. Stress, in the form of high light, increased the growth response to IAA by leaf strips and reduced growth inhibition response by intact detached leaves. Endogenous free IAA content of intact attached leaves and excised leaf strips was found not to change over the course of 24 h. Together these results indicate growth induction of Arabidopsis leaf blade tissue by IAA requires both substantial wounding as well as detachment from the plant and suggests in vivo that IAA induces parallel pathways leading to growth inhibition. PMID:22101347

  4. Identification of the cells involved in auxin transport in maize mesocotyl

    SciTech Connect

    Jones, A.M. )

    1989-04-01

    A study was undertaken to identify by a direct method the cells involved in auxin transport through maize mesocotyl tissue. The auxin photoaffinity labeling agent, 7-({sup 3}H), 5-azidoindole 3-acetic acid (N{sub 3}IAA), was loaded into excised stem tissue from a cut end. Polar transport of this analog was demonstrated over 4 hours by comparing uptake into tissue loaded with N{sub 3}IAA from the apical vs. the basal end. Triiodobenzoic acid, an auxin transport inhibitor, inhibited N{sub 3}IAA uptake into tissue. Tissue which had taken up the photoaffinity labeling agent was photolyzed to covalently fix the radioisotope within cells. This tissue was sectioned and subjected to in situ autoradiography. The outermost cell of epidermal tissue and certain files of cells in vascular tissue were densely labeled indicating that on a per cell basis these two cell types are most actively transporting auxin.

  5. A solvent extraction approach to recover acetic acid from mixed waste acids produced during semiconductor wafer process.

    PubMed

    Shin, Chang-Hoon; Kim, Ju-Yup; Kim, Jun-Young; Kim, Hyun-Sang; Lee, Hyang-Sook; Mohapatra, Debasish; Ahn, Jae-Woo; Ahn, Jong-Gwan; Bae, Wookeun

    2009-03-15

    Recovery of acetic acid (HAc) from the waste etching solution discharged from silicon wafer manufacturing process has been attempted by using solvent extraction process. For this purpose 2-ethylhexyl alcohol (EHA) was used as organic solvent. In the pre-treatment stage >99% silicon and hydrofluoric acid was removed from the solution by precipitation. The synthesized product, Na(2)SiF(6) having 98.2% purity was considered of commercial grade having good market value. The waste solution containing 279 g/L acetic acid, 513 g/L nitric acid, 0.9 g/L hydrofluoric acid and 0.030 g/L silicon was used for solvent extraction study. From the batch test results equilibrium conditions for HAc recovery were optimized and found to be 4 stages of extraction at an organic:aqueous (O:A) ratio of 3, 4 stages of scrubbing and 4 stages of stripping at an O:A ratio of 1. Deionized water (DW) was used as stripping agent to elute HAc from organic phase. In the whole batch process 96.3% acetic acid recovery was achieved. Continuous operations were successfully conducted for 100 h using a mixer-settler to examine the feasibility of the extraction system for its possible commercial application. Finally, a complete process flowsheet with material balance for the separation and recovery of HAc has been proposed. PMID:18639982

  6. Effects of bisphenol A, an environmental endocrine disruptor, on the endogenous hormones of plants.

    PubMed

    Wang, Shengman; Wang, Lihong; Hua, Weiqi; Zhou, Min; Wang, Qingqing; Zhou, Qing; Huang, Xiaohua

    2015-11-01

    Bisphenol A (BPA) is a ubiquitous endocrine-disrupting chemical in the environment that exerts potential harm to plants. Phytohormones play important roles both in regulating multiple aspects of plant growth and in plants' responses to environmental stresses. But how BPA affects plant growth by regulating endogenous hormones remains poorly understood. Here, we found that treatment with 1.5 mg L(-1) BPA improved the growth of soybean seedlings, companied by increases in the contents of indole-3-acetic acid (IAA) and zeatin (ZT), and decreases in the ratios of abscisic acid (ABA)/IAA, ABA/gibberellic acid (GA), ABA/ZT, ethylene (ETH)/GA, ETH/IAA, and ETH/ZT. Treatment with higher concentrations of BPA (from 3 to 96 mg L(-1)) inhibited the growth of soybean seedlings, meanwhile, decreased the contents of IAA, GA, ZT, and ETH, and increased the content of ABA and the ratios of ABA/IAA, ABA/GA, ABA/ZT, ETH/GA, ETH/IAA, and ETH/ZT. The increases in the ratios of growth and stress hormones were correlated with the increase in the BPA content of the roots. Thus, BPA could affect plant growth through changing the levels of single endogenous hormone and the ratios of growth and stress hormones in the roots because of BPA absorption by the roots. PMID:26150296

  7. Endogenous Auxin and Ethylene in the Lichen Ramalina duriaei1

    PubMed Central

    Epstein, Ephraim; Sagee, Oded; Cohen, Jerry D.; Garty, Jacob

    1986-01-01

    Indole-3-acetic acid (IAA) levels and ethylene evolution rates were measured in a fruticose lichen Ramalina duriaei collected from carob trees growing in northeast Israel. IAA levels were estimated by gas liquid chromatography with electron capture detection of the pentafluorobenzyl ester and also by enzyme-linked immunosorbent assay following methylation. The identity of the isolated IAA was confirmed by gas chromatography-mass spectrometry of both the methyl and the pentafluorobenzyl ester. IAA levels in lichens 1 year after transplanting to an air-polluted urban site were found to be lower than in the control thalli left at a nonpolluted, rural site. The material from the latter contained about 2.5 micrograms per gram fresh weight free IAA and 0.5 microgram per gram fresh weight conjugated IAA, while the urban material contained 0.3 microgram per gram each of free and conjugated IAA. Ethylene production rate was 1.0 nanoliter per gram fresh weight per hour in the material from the rural site and 1.5 nanoliters per gram fresh weight per hour in material from the urban site. PMID:16665145

  8. Auxin and Cell Wall Invertase Related Signaling during Rice Grain Development

    PubMed Central

    Russell French, Sarah; Abu-Zaitoon, Yousef; Uddin, Md. Myn; Bennett, Karina; Nonhebel, Heather M.

    2014-01-01

    Indole-3-acetic acid (IAA) synthesis is required for grain-fill in maize and appears to be regulated by cell-wall invertase (CWIN) activity. OsYUC12 is one of three IAA biosynthesis genes we previously reported as expressed during early rice grain development, correlating with a large increase in IAA content of the grain. This work aimed to investigate further the role of OsYUC12 and its relationship to CWIN activity and invertase inhibitors (INVINH). The analysis shows a brief peak of OsYUC12 expression early in endosperm development. Meta-analysis of microarray data, confirmed by quantitative expression analysis, revealed that OsYUC12 is coexpressed with OsIAA29, which encodes an unusual AUX/IAA transcription factor previously reported as poorly expressed. Maximum expression of OsYUC12 and OsIAA29 coincided with maximum CWIN activity, but also with a peak in INVINH expression. Unlike ZmYUC1, OsYUC12 expression is not reduced in the rice CWIN mutant, gif1. Several reports have investigated CWIN expression in rice grains but none has reported on expression of INVINH in this species. We show that rice has 54 genes encoding putative invertase/pectin methylesterase inhibitors, seven of which are expressed exclusively during grain development. Our results suggest a more complex relationship between IAA, CWIN, and INVINH than previously proposed. PMID:27135493

  9. Root cap-dependent gravitropic U-turn of maize root requires light-induced auxin biosynthesis via the YUC pathway in the root apex.

    PubMed

    Suzuki, Hiromi; Yokawa, Ken; Nakano, Sayuri; Yoshida, Yuriko; Fabrissin, Isabelle; Okamoto, Takashi; Baluška, František; Koshiba, Tomokazu

    2016-08-01

    Gravitropism refers to the growth or movement of plants that is influenced by gravity. Roots exhibit positive gravitropism, and the root cap is thought to be the gravity-sensing site. In some plants, the root cap requires light irradiation for positive gravitropic responses. However, the mechanisms regulating this phenomenon are unknown. We herein report that maize roots exposed to white light continuously for ≥1-2h show increased indole-3-acetic acid (IAA) levels in the root tips, especially in the transition zone (1-3mm from the tip). Treatment with IAA biosynthesis inhibitors yucasin and l-kynurenine prevented any increases in IAA content and root curvature under light conditions. Analyses of the incorporation of a stable isotope label from tryptophan into IAA revealed that some of the IAA in roots was synthesized in the root apex. Furthermore, Zmvt2 and Zmyuc gene transcripts were detected in the root apex. One of the Zmyuc genes (ZM2G141383) was up-regulated by light irradiation in the 0-1mm tip region. Our findings suggest that IAA accumulation in the transition zone is due to light-induced activation of Zmyuc gene expression in the 0-1mm root apex region. Light-induced changes in IAA levels and distributions mediate the maize root gravitropic U-turn. PMID:27307546

  10. CgOpt1, a putative oligopeptide transporter from Colletotrichum gloeosporioides that is involved in responses to auxin and pathogenicity

    PubMed Central

    2009-01-01

    Background The fungus Colletotrichum gloeosporioides f. sp. aeschynomene produces high levels of indole-3-acetic acid (IAA) in axenic cultures and during plant infection. We generated a suppression subtractive hybridization library enriched for IAA-induced genes and identified a clone, which was highly expressed in IAA-containing medium. Results The corresponding gene showed similarity to oligopeptide transporters of the OPT family and was therefore named CgOPT1. Expression of CgOPT1 in mycelia was low, and was enhanced by external application of IAA. cgopt1-silenced mutants produced less spores, had reduced pigmentation, and were less pathogenic to plants than the wild-type strain. IAA enhanced spore formation and caused changes in colony morphology in the wild-type strain, but had no effect on spore formation or colony morphology of the cgopt1-silenced mutants. Conclusion Our results show that IAA induces developmental changes in C. gloeosporioides. These changes are blocked in cgopt1-silenced mutants, suggesting that this protein is involved in regulation of fungal response to IAA. CgOPT1 is also necessary for full virulence, but it is unclear whether this phenotype is related to auxin. PMID:19698103

  11. Root cap-dependent gravitropic U-turn of maize root requires light-induced auxin biosynthesis via the YUC pathway in the root apex

    PubMed Central

    Suzuki, Hiromi; Yokawa, Ken; Nakano, Sayuri; Yoshida, Yuriko; Fabrissin, Isabelle; Okamoto, Takashi; Baluška, František; Koshiba, Tomokazu

    2016-01-01

    Gravitropism refers to the growth or movement of plants that is influenced by gravity. Roots exhibit positive gravitropism, and the root cap is thought to be the gravity-sensing site. In some plants, the root cap requires light irradiation for positive gravitropic responses. However, the mechanisms regulating this phenomenon are unknown. We herein report that maize roots exposed to white light continuously for ≥1–2h show increased indole-3-acetic acid (IAA) levels in the root tips, especially in the transition zone (1–3mm from the tip). Treatment with IAA biosynthesis inhibitors yucasin and l-kynurenine prevented any increases in IAA content and root curvature under light conditions. Analyses of the incorporation of a stable isotope label from tryptophan into IAA revealed that some of the IAA in roots was synthesized in the root apex. Furthermore, Zmvt2 and Zmyuc gene transcripts were detected in the root apex. One of the Zmyuc genes (ZM2G141383) was up-regulated by light irradiation in the 0–1mm tip region. Our findings suggest that IAA accumulation in the transition zone is due to light-induced activation of Zmyuc gene expression in the 0–1mm root apex region. Light-induced changes in IAA levels and distributions mediate the maize root gravitropic U-turn. PMID:27307546

  12. Amino acids

    MedlinePlus

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  13. The manipulation of auxin in the abscission zone cells of Arabidopsis flowers reveals that indoleacetic acid signaling is a prerequisite for organ shedding.

    PubMed

    Basu, Manojit M; González-Carranza, Zinnia H; Azam-Ali, Sayed; Tang, Shouya; Shahid, Ahmad Ali; Roberts, Jeremy A

    2013-05-01

    A number of novel strategies were employed to examine the role of indoleacetic acid (IAA) in regulating floral organ abscission in Arabidopsis (Arabidopsis thaliana). Analysis of auxin influx facilitator expression in β-glucuronidase reporter plants revealed that AUXIN RESISTANT1, LIKE AUX1, and LAX3 were specifically up-regulated at the site of floral organ shedding. Flowers from mutants where individual family members were down-regulated exhibited a reduction in the force necessary to bring about petal separation; however, the effect was not additive in double or quadruple mutants. Using the promoter of a polygalacturonase (At2g41850), active primarily in cells undergoing separation, to drive expression of the bacterial genes iaaL and iaaM, we have shown that it is possible to manipulate auxin activity specifically within the floral organ abscission zone (AZ). Analysis of petal breakstrength reveals that if IAA AZ levels are reduced, shedding takes place prematurely, while if they are enhanced, organ loss is delayed. The At2g41850 promoter was also used to transactivate the gain-of-function AXR3-1 gene in order to disrupt auxin signaling specifically within the floral organ AZ cells. Flowers from transactivated lines failed to shed their sepals, petals, and anthers during pod expansion and maturity, and these organs frequently remained attached to the plant even after silique desiccation and dehiscence had taken place. These observations support a key role for IAA in the regulation of abscission in planta and reveal, to our knowledge for the first time, a requirement for a functional IAA signaling pathway in AZ cells for organ shedding to take place. PMID:23509178

  14. Distribution and cellular localization of imidazoleacetic acid-ribotide, an endogenous ligand at imidazol(in)e and adrenergic receptors, in rat brain

    PubMed Central

    Friedrich, Victor L.; Martinelli, Giorgio P.; Prell, George D.; Holstein, Gay R.

    2007-01-01

    Imidazoleacetic acid-ribotide (IAA-RP) is a putative neurotransmitter/modulator recently discovered in mammalian brain. The present study examines the distribution of IAA-RP in the rat CNS using a highly specific antiserum raised in rabbit against IAA-RP with immunostaining of aldehyde-fixed rat CNS. IAA-RP-immunoreactive neurons were present throughout the neuraxis; neuroglia were not labeled. In each region, only a subset of the neuronal pool was immunostained. In the forebrain, ribotide-immunolabeled neurons were common in neocortex, in hippocampal formation, and in subcortical structures including basal ganglia, thalamus and hypothalamus. Labeling was prominent limbic areas including olfactory bulb, basal forebrain, pyriform cortex and amygdala. In the mid- and hindbrain, immunolabled neurons were concentrated in specific nuclei and, in some areas, in specific subregions of those nuclei. Structures of the motor system, including cranial nerve motor nuclei, precerebellar nuclei, the substantia nigra, and the red nucleus were clearly labeled. Staining was intense in cells and/or puncta in the rostral and caudal ventrolateral medullary reticular formation, nucleus tractus solitarius and the caudal vestibular nuclear complex. Within neurons, the ribotide was found predominantly in somata and dendrites; some myelinated axons and occasional synaptic terminals were also immunostained. These data indicate that IAA-RP contributes to the neurochemical phenotype of many neuronal populations further support our suggestion that, in autonomic structures, the IAA-RP may serve as a chemical mediator in complex circuits involved in blood pressure regulation and, more generally, sympathetic drive. PMID:17210242

  15. Ectomycorrhizal fungi and exogenous auxins influence root and mycorrhiza formation of Scots pine hypocotyl cuttings in vitro.

    PubMed

    Niemi, K; Vuorinen, T; Ernstsen, A; Häggman, H

    2002-12-01

    We studied the ability of the ectomycorrhizal (ECM) fungi, Pisolithus tinctorius (Pers.) Coker and Couch and Paxillus involutus (Batsch) Fr. (Strain H), to produce indole-3-acetic acid (IAA) and to affect the formation and growth of roots on Scots pine (Pinus sylvestris L.) hypocotyl cuttings in vitro. Effects of indole-3-butyric acid (IBA) and the auxin transport inhibitor, 2,3,5-triiodobenzoic acid (TIBA), on rooting and the cutting-fungus interaction were also studied. Both fungi produced IAA in the absence of exogenous tryptophan, but the mycelium and culture filtrate of Pisolithus tinctorius contained higher concentrations of free and conjugated IAA than the mycelium and culture filtrate of Paxillus involutus. Inoculation with either fungus or short-term application of culture filtrate of either fungus to the base of hypocotyl cuttings enhanced root formation. Inoculation with either fungus was even more effective in enhancing root formation than treatment of the hypocotyl bases with IBA. Fungal IAA production was not directly correlated with root formation, because rooting was enhanced more by Paxillus involutus than by Pisolithus tinctorius. This suggests that, in addition to IAA, other fungal components play an important role in root formation. Treatment with 5 microM TIBA increased the rooting percentage of non-inoculated cuttings, as well as of cuttings inoculated with Pisolithus tinctorius, perhaps as a result of accumulation of IAA at the cutting base. However, the marked reduction in growth of Pisolithus tinctorius in the presence of TIBA suggests that the effects of TIBA on rooting are complicated and not solely related to IAA metabolism. The high IAA-producer, Pisolithus tinctorius, formed mycorrhizas, and the IBA treatment increased mycorrhizal frequency in this species, whereas TIBA decreased it. Paxillus involutus did not form mycorrhizas, indicating that a low concentration of IAA together with other fungal components were sufficient to stimulate

  16. Apoplastic H2 O2 plays a critical role in axillary bud outgrowth by altering auxin and cytokinin homeostasis in tomato plants.

    PubMed

    Chen, Xiao-Juan; Xia, Xiao-Jian; Guo, Xie; Zhou, Yan-Hong; Shi, Kai; Zhou, Jie; Yu, Jing-Quan

    2016-09-01

    Although phytohormones such as indole-3-acetic acid (IAA), cytokinin (CK) and strigolactone are important modulators of plant architecture, it remains unclear whether reactive oxygen species are involved in the regulation of phytohormone-dependent axillary bud outgrowth in plants. We used diverse techniques, including transcriptional suppression, HPLC-MS, biochemical methodologies and gene transcript analysis to investigate the signaling pathway for apoplastic hydrogen peroxide (H2 O2 )-induced axillary bud outgrowth. Silencing of tomato RESPIRATORY BURST OXIDASE HOMOLOG 1 (RBOH1) and WHITEFLY INDUCED 1 (WFI1), two important genes involved in H2 O2 production in the apoplast, enhanced bud outgrowth, decreased transcript of FZY - a rate-limiting gene in IAA biosynthesis and IAA accumulation in the apex - and increased the transcript of IPT2 involved in CK biosynthesis and CK accumulation in the stem node. These effects were fully abolished by the application of exogenous H2 O2 . Both decapitation and the silencing of FZY promoted bud outgrowth, and downregulated and upregulated the transcripts for IAA3 and IAA15, and IPT2, respectively. However, these effects were not blocked by treatment with exogenous H2 O2 but by napthaleneacetic acid (NAA) treatment. These results suggest that RBOHs-dependent apoplastic H2 O2 promotes IAA biosynthesis in the apex, which, in turn, inhibits CK biosynthesis and subsequent bud outgrowth in tomato plants. PMID:27240824

  17. Micropropagation of Madhuca longifolia (Koenig) MacBride var. latifolia Roxb.

    PubMed

    Rout, G R; Das, P

    1993-07-01

    Bud break and multiple shoots were induced in apical and axillary meristems derived from 10-d old seedlings of Madhuca longifolia var. latifolia on Murashige and Skoog (MS) medium supplemented with 1.0 mg/l N(6)-benzyladenine (BA) singly or in combinatiobn with 1-naphthalene acetic acid (NAA), indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA). Excised shoots were rooted on half-strength MS with IBA (1.0 mg/l) after 18d of culture. Regenerated plantlets were acclimatized and successfully transferred to soil. PMID:24196112

  18. Herring roe protein has a high digestible indispensable amino acid score (DIAAS) using a dynamic in vitro gastrointestinal model.

    PubMed

    Havenaar, Robert; Maathuis, Annet; de Jong, Aard; Mancinelli, Daniele; Berger, Alvin; Bellmann, Susann

    2016-08-01

    It is hypothesized that the digestible indispensable amino acid score (DIAAS) can be determined based on dynamic in vitro gastrointestinal digestion experiments as replacement for invasive animal studies. We determined the in vitro DIAAS for immature herring eggs (roe) proteins in comparison with reference proteins. The true ileal digestibility of protein and indispensable amino acids (IAA) was measured under human conditions simulated in a gastrointestinal model (tiny-TIM). The in vitro true ileal digestibility of ovalbumin, cooked and raw chicken egg white, and casein was similar to that found in humans (r(2) = 0.96), providing a casual observation to support the validity of tiny-TIM. The digestibility of the immature herring egg proteins was 71% to 92%. The highest IAA digestibility was found for immature whole herring egg protein (55%-80%) in comparison to immature herring egg membrane and immature de-membraned herring protein (50%-70%). The DIAAS as recommended by FAO for children and adults, but measured in vitro, were 91% for immature whole herring egg protein (lysine first limiting), 71% for immature herring egg membrane protein (histidine first limiting), and 88% for immature herring egg de-membraned protein (sulfur AA first limiting). True ileal protein and amino acid digestibility can be determined in a dynamic gastrointestinal model, such as tiny-TIM, which can be used for estimating the DIAAS. Immature herring egg proteins, a previously underutilized resource, were determined to be an important and valuable source of IAA for human consumption. PMID:27440534

  19. Auxin and plant-microbe interactions.

    PubMed

    Spaepen, Stijn; Vanderleyden, Jos

    2011-04-01

    Microbial synthesis of the phytohormone auxin has been known for a long time. This property is best documented for bacteria that interact with plants because bacterial auxin can cause interference with the many plant developmental processes regulated by auxin. Auxin biosynthesis in bacteria can occur via multiple pathways as has been observed in plants. There is also increasing evidence that indole-3-acetic acid (IAA), the major naturally occurring auxin, is a signaling molecule in microorganisms because IAA affects gene expression in some microorganisms. Therefore, IAA can act as a reciprocal signaling molecule in microbe-plant interactions. Interest in microbial synthesis of auxin is also increasing in yet another recently discovered property of auxin in Arabidopsis. Down-regulation of auxin signaling is part of the plant defense system against phytopathogenic bacteria. Exogenous application of auxin, e.g., produced by the pathogen, enhances susceptibility to the bacterial pathogen. PMID:21084388

  20. The diageotropica mutant of tomato lacks high specific activity auxin sites

    SciTech Connect

    Hicks, G.R.; Lomax, T.L. ); Rayle, D.L. )

    1989-04-01

    Tomato (Lycopersicum esculentum, Mill) plants homozygous for the single gene diageotropica (dgt) mutation have reduced shoot growth, abnormal vascular tissue, altered leaf morphology, and lack of lateral root branching. These and other morphological and physiological abnormalities suggest that dgt plants are unable to respond to the plant growth hormone auxin (indole-3-acetic acid, IAA). The photoaffinity auxin analogue {sup 3}H-5N{sub 3}-IAA specifically labels a polypeptide doublet of 40 ad 42 kD in membrane preparations from stems of the parental variety VFN8, but not from stems of dgt. In elongation tests, excised dgt roots respond in the same manner to IAA an VFN8 roots. These data suggest that the two polypeptides are part of a physiologically important auxin receptor system which is altered in a tissue-specific manner in the mutant.

  1. Possible effects of organelle charge and density on cell metabolism. [chemical response to gravitational stimulus

    NASA Technical Reports Server (NTRS)

    Bandurski, Robert S.; Schulze, Aga; Domagalski, W.

    1986-01-01

    A system of perception and transduction involving the gravity-induced asymmetric distribution of a plant growth hormone is studied. A theory is constructed which assumes that the perception of the gravitational stimulus involved a perturbation of the plant's bioelectric field and that the transduction of the stimulus involved voltage-gating of hormone movement from the plant's vascular tissue into the hormone responsive growing tissue. Particular attention is focused on the barriers to indole-3-acetic acid (IAA) transport from the seed to the mesocotyl cortex, the protoinhibition of IAA movement from the endosperm to the shoot, the effects of the gravitational stimulus on the movement of IAA from the kernel to the shoot, electrochemical gating as a target for the gravity stimulus, and the gravity sensing mechanism.

  2. Auxin and Plant-Microbe Interactions

    PubMed Central

    Spaepen, Stijn; Vanderleyden, Jos

    2011-01-01

    Microbial synthesis of the phytohormone auxin has been known for a long time. This property is best documented for bacteria that interact with plants because bacterial auxin can cause interference with the many plant developmental processes regulated by auxin. Auxin biosynthesis in bacteria can occur via multiple pathways as has been observed in plants. There is also increasing evidence that indole-3-acetic acid (IAA), the major naturally occurring auxin, is a signaling molecule in microorganisms because IAA affects gene expression in some microorganisms. Therefore, IAA can act as a reciprocal signaling molecule in microbe-plant interactions. Interest in microbial synthesis of auxin is also increasing in yet another recently discovered property of auxin in Arabidopsis. Down-regulation of auxin signaling is part of the plant defense system against phytopathogenic bacteria. Exogenous application of auxin, e.g., produced by the pathogen, enhances susceptibility to the bacterial pathogen. PMID:21084388

  3. Alterations of ultrastructure and elemental composition in cultured neonatal rat cardiac myocytes after metabolic inhibition with iodoacetic acid.

    PubMed

    Buja, L M; Hagler, H K; Parsons, D; Chien, K; Reynolds, R C; Willerson, J T

    1985-10-01

    The purpose of this study was to document changes in cellular fine structure and elemental composition, and their relationship to progression of cell injury, in cultured neonatal rat cardiac myocytes in which impaired energy metabolism was produced by the metabolic inhibitor, iodoacetic acid (IAA). In order to quantitate changes in the concentrations of elements and their subcellular distribution in individual myocytes, electron probe x-ray microanalysis was performed on freeze-dried cryosections of rapidly frozen cells. After 1 hour of exposure to IAA, ATP level was not significantly reduced. Most cells exhibited minimal ultrastructural alterations and had normal elemental profiles, whereas some cells (10 to 25%) had increased sodium and calcium in mitochondria and cytoplasm. After exposure to IAA for 1.5, 2, or 4 hours, the ATP level was reduced to below one third of control, and remained decreased 24 hours after removal of IAA, indicating irreversible depression of this variable. After exposure to IAA for 1.5 hours no longer, many cells showed severe ultrastructural alterations, including contraction or swelling of mitochondria and distortion of the cristae, myofibrillar hypercontraction, and formation of fluid-filled blebs. At 1.5 and 2 hours, approximately 75% or more of the myocytes had increased sodium and calcium and decreased potassium and magnesium in mitochondria, nuclei, and cytoplasm. Thus, the development of an increased calcium concentration in cytoplasm as well as mitochondria of most myocytes was a feature of this transitional period. These data indicate that progressive alterations in the levels and distribution of elements accompany the development of severe ultrastructural changes and irreversible injury in response to impaired energy metabolism in cultured myocytes. These elemental alterations include accumulation of calcium in cytoplasm and mitochondria of myocytes in this model. PMID:2413276

  4. Comparative effects of wild type Stenotrophomonas maltophilia and its indole acetic acid-deficient mutants on wheat.

    PubMed

    Hassan, T U; Bano, A

    2016-09-01

    The present investigation evaluated the role of Stenotrophomonas maltophilia and its IAA-deficient mutant on soil health and plant growth under salinity stress in the presence of tryptophan. In the first phase, S. maltophilia isolated from roots of the halo- phytic herb, Cenchrus ciliaris was used as bio-inoculant on wheat grown in saline sodic soil. A field experiment was conducted at Soil Salinity Research Institute during 2010-2011. Treatments included seed inoculation with S. maltophilia with or without tryptophan; uninoculated untreated plants were taken as control. An aqueous solution of tryptophan was added to rhizosphere soil at 1 μg l(_1) after seed germination. Inoculation with S. maltophilia significantly increased soil organic matter, enhanced (20-30%) availability of P, K, Ca and NO3 -N and decreased Na content and electrical conductivity of rhizosphere soil. Plant height, fresh weight, proline and phytohormone content of leaves were increased 30-40% over the control. Activities of superoxide dismutase (SOD) and peroxidase (POD) were 40-50% higher than control. Addition of tryptophan further augmented (10-15%) growth parameters, whereas NO3 -N, P, K and Ca content, proline content and SOD and POD increased 20-30%. In a second phase, indoleacetic acid (IAA)-deficient mutants of S. maltophilia were constructed and evaluated for conversion of tryptophan to IAA at the University of Calgary, Canada, during 2013-2014. About 1800 trans-conjugants were constructed that were unable to produce IAA in the presence of tryptophan. The results suggest that tryptophan assisted S. maltophilia in the amelioration of salt stress, and that IAA played positive role in induction of salt tolerance. PMID:27263526

  5. Hormone crosstalk in wound stress response: wound-inducible amidohydrolases can simultaneously regulate jasmonate and auxin homeostasis in Arabidopsis thaliana

    PubMed Central

    Zhang, Tong; Poudel, Arati N.; Jewell, Jeremy B.; Kitaoka, Naoki; Staswick, Paul; Matsuura, Hideyuki; Koo, Abraham J.

    2016-01-01

    Jasmonate (JA) and auxin are essential hormones in plant development and stress responses. While the two govern distinct physiological processes, their signaling pathways interact at various levels. Recently, members of the Arabidopsis indole-3-acetic acid (IAA) amidohydrolase (IAH) family were reported to metabolize jasmonoyl-isoleucine (JA-Ile), a bioactive form of JA. Here, we characterized three IAH members, ILR1, ILL6, and IAR3, for their function in JA and IAA metabolism and signaling. Expression of all three genes in leaves was up-regulated by wounding or JA, but not by IAA. Purified recombinant proteins showed overlapping but distinct substrate specificities for diverse amino acid conjugates of JA and IAA. Perturbed patterns of the endogenous JA profile in plants overexpressing or knocked-out for the three genes were consistent with ILL6 and IAR3, but not ILR1, being the JA amidohydrolases. Increased turnover of JA-Ile in the ILL6- and IAR3-overexpressing plants created symptoms of JA deficiency whereas increased free IAA by overexpression of ILR1 and IAR3 made plants hypersensitive to exogenous IAA conjugates. Surprisingly, ILL6 overexpression rendered plants highly resistant to exogenous IAA conjugates, indicating its interference with IAA conjugate hydrolysis. Fluorescent protein-tagged IAR3 and ILL6 co-localized with the endoplasmic reticulum-localized JA-Ile 12-hydroxylase, CYP94B3. Together, these results demonstrate that in wounded leaves JA-inducible amidohydrolases contribute to regulate active IAA and JA-Ile levels, promoting auxin signaling while attenuating JA signaling. This mechanism represents an example of a metabolic-level crosstalk between the auxin and JA signaling pathways. PMID:26672615

  6. Arabidopsis WRKY57 functions as a node of convergence for jasmonic acid- and auxin-mediated signaling in jasmonic acid-induced leaf senescence.

    PubMed

    Jiang, Yanjuan; Liang, Gang; Yang, Shizhuo; Yu, Diqiu

    2014-01-01

    Leaf senescence is regulated by diverse developmental and environmental factors. Exogenous jasmonic acid (JA) can induce leaf senescence, whereas auxin suppresses this physiological process. Crosstalk between JA and auxin signaling has been well studied, but not during JA-induced leaf senescence. Here, we found that upon methyl jasmonate treatment, Arabidopsis thaliana wrky57 mutants produced typical leaf senescence symptoms, such as yellowing leaves, low chlorophyll content, and high cell death rates. Further investigation suggested that senescence-associated genes were upregulated in the wrky57 mutants. Chromatin immunoprecipitation experiments revealed that WRKY57 directly binds to the promoters of SENESCENCE4 and SENESCENCE-ASSOCIATED GENE12 and represses their transcription. In vivo and in vitro experiments suggested that WRKY57 interacts with JASMONATE ZIM-DOMAIN4/8 (JAZ4/8) and the AUX/IAA protein IAA29, repressors of the JA and auxin signaling pathways, respectively. Consistent with the opposing functions of JA and auxin in JA-induced leaf senescence, JAZ4/8 and IAA29 also displayed opposite functions in JA-induced leaf senescence and competitively interacted with WRKY57. Our results suggested that the JA-induced leaf senescence process can be antagonized by auxin via WRKY57. Moreover, WRKY57 protein levels were downregulated by JA but upregulated by auxin. Therefore, as a repressor in JA-induced leaf senescence, WRKY57 is a common component of the JA- and auxin-mediated signaling pathways. PMID:24424094

  7. Folic Acid

    MedlinePlus

    Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

  8. Folic Acid

    MedlinePlus

    Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by ... Folic acid comes in tablets. It usually is taken once a day. Follow the directions on your prescription label ...

  9. Aspartic acid

    MedlinePlus

    ... also called asparaginic acid. Aspartic acid helps every cell in the body work. It plays a role in: Hormone production and release Normal nervous system function Plant sources of aspartic acid include: Legumes such as ...

  10. Floral Induction of Vegetative Plants Supplied a Purified Fraction of Deoxyribonucleic Acid from Stems of Flowering Plants 1

    PubMed Central

    Wardell, William L.

    1977-01-01

    It has been found that floral induced stems of flowering tobacco (Nicotiana tabacum cv. Wis. 38) plants contain large amounts of rapidly renaturing DNA, whereas noninduced stems of vegetative plants contain only small amounts. In addition, it has been shown that the striking qualitative difference in DNA between stems of flowering and vegetative plants mimics the over-all quantitative difference in DNA content (on a fresh weight basis). Therefore, the extra DNA in stems of flowering plants seems, at least in part, to represent preferential synthesis of rapidly renaturing DNA. Rapidly renatured DNA (flowering plants) has been purified (cesium chloride gradients) from heated-cooled DNA solution and under noninductive conditions has been tested for floral activity. It has been found that when rapidly renatured DNA in buffer solution is supplied to axillary vegetative buds of vegetative plants and then the axillary buds are defoliated every 4th day for 12 days, the treated buds change into flower buds. On the other hand, control axillary buds supplied buffer solution alone remain vegetative. In stem segments from flowering plants, the concept, discussed in previous reports, that indole-3-acetic acid may modify in vitro bud expression by directly affecting DNA synthesis has been reviewed. On the basis of this report, the concept is elaborated by proposing here that indole-3-acetic acid may act partially in bud expression by directly suppressing synthesis of rapidly renaturing DNA. PMID:16660207

  11. Acid Rain.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  12. Impaired Auxin Biosynthesis in the defective endosperm18 Mutant Is Due to Mutational Loss of Expression in the ZmYuc1 Gene Encoding Endosperm-Specific YUCCA1 Protein in Maize1[C][W][OA

    PubMed Central

    Bernardi, Jamila; Lanubile, Alessandra; Li, Qin-Bao; Kumar, Dibyendu; Kladnik, Aleš; Cook, Sam D.; Ross, John J.; Marocco, Adriano; Chourey, Prem S.

    2012-01-01

    The phytohormone auxin (indole-3-acetic acid [IAA]) plays a fundamental role in vegetative and reproductive plant development. Here, we characterized a seed-specific viable maize (Zea mays) mutant, defective endosperm18 (de18) that is impaired in IAA biosynthesis. de18 endosperm showed large reductions of free IAA levels and is known to have approximately 40% less dry mass, compared with De18. Cellular analyses showed lower total cell number, smaller cell volume, and reduced level of endoreduplication in the mutant endosperm. Gene expression analyses of seed-specific tryptophan-dependent IAA pathway genes, maize Yucca1 (ZmYuc1), and two tryptophan-aminotransferase co-orthologs were performed to understand the molecular basis of the IAA deficiency in the mutant. Temporally, all three genes showed high expression coincident with high IAA levels; however, only ZmYuc1 correlated with the reduced IAA levels in the mutant throughout endosperm development. Furthermore, sequence analyses of ZmYuc1 complementary DNA and genomic clones revealed many changes specific to the mutant, including a 2-bp insertion that generated a premature stop codon and a truncated YUC1 protein of 212 amino acids, compared with the 400 amino acids in the De18. The putative, approximately 1.5-kb, Yuc1 promoter region also showed many rearrangements, including a 151-bp deletion in the mutant. Our concurrent high-density mapping and annotation studies of chromosome 10, contig 395, showed that the De18 locus was tightly linked to the gene ZmYuc1. Collectively, the data suggest that the molecular changes in the ZmYuc1 gene encoding the YUC1 protein are the causal basis of impairment in a critical step in IAA biosynthesis, essential for normal endosperm development in maize. PMID:22961134

  13. Isomerization of 1-O-indol-3-ylacetyl-beta-D-glucose. Enzymatic hydrolysis of 1-O, 4-O, and 6-O-indol-3-ylacetyl-beta-D-glucose and the enzymatic synthesis of indole-3-acetyl glycerol by a hormone metabolizing complex

    NASA Technical Reports Server (NTRS)

    Kowalczyk, S.; Bandurski, R. S.

    1990-01-01

    The first compound in the series of reactions leading to the ester conjugates of indole-3-acetic acid (IAA) in kernels of Zea mays sweet corn is the acyl alkyl acetal, 1-O-indol-3-ylacetyl-beta-D-glucose (1-O-IAGlu). The enzyme catalyzing the synthesis of this compound is UDP-glucose:indol-3-ylacetate glucosyl-transferase (IAGlu synthase). The IAA moiety of the high energy compound 1-O-IAGlu may be enzymatically transferred to myo-inositol or to glycerol or the 1-O-IAGlu may be enzymatically hydrolyzed. Alternatively, nonenzymatic acyl migration may occur to yield the 2-O, 4-O, and 6-O esters of IAA and glucose. The 4-O and 6-O esters may then be enzymatically hydrolyzed to yield free IAA and glucose. This work reports new enzymatic activities, the transfer of IAA from 1-O-IAGlu to glycerol, and the enzyme-catalyzed hydrolysis of 4-O and 6-O-IAGlu. Data is also presented on the rate of non-enzymatic acyl migration of IAA from the 1-O to the 4-O and 6-O positions of glucose. We also report that enzymes catalyzing the synthesis of 1-O-IAGlu and the hydrolysis of 1-O, 4-O, and 6-O-IAGlu fractionate as a hormone metabolizing complex. The association of synthetic and hydrolytic capabilities in enzymes which cofractionate may have physiological significance.

  14. Asymmetric distribution of auxin correlates with gravitropism and phototropism but not with autostraightening (autotropism) in pea epicotyls.

    PubMed

    Haga, Ken; Iino, Moritoshi

    2006-01-01

    The relationships between the distribution of the native auxin indole-3-acetic acid (IAA) and tropisms in the epicotyl of red light-grown pea (Pisum sativum L.) seedlings have been investigated. The distribution measurement was made in a defined zone of the third internode, using (3)H-IAA applied from the plumule as a tracer. The tropisms investigated were gravitropism, pulse-induced phototropism, and time-dependent phototropism. The investigation was extended to the phase of autostraightening (autotropism) that followed gravitropic curvature. It was found that IAA is asymmetrically distributed between the two halves of the zone, with a greater IAA level occurring on the convex side, at early stages of gravitropic and phototropic curvatures. This asymmetry was found in epidermal peels and, except for one case (pulse-induced phototropism), no asymmetry was detected in whole tissues. It was concluded, in support of earlier results, that auxin asymmetry mediates gravitropism and phototropism and that the epidermis or peripheral cell layers play an important role in the establishment of auxin asymmetry in pea epicotyls. During autostraightening, which results from a reversal of growth asymmetry, the extent of IAA asymmetry was reduced, but its direction was not reversed. This result demonstrated that autostraightening is not regulated through auxin distribution. In this study, the growth on either side of the investigated zone was also measured. In some cases, the measured IAA distribution could not adequately explain the local growth rate, necessitating further detailed investigation. PMID:16467412

  15. Small-molecule auxin inhibitors that target YUCCA are powerful tools for studying auxin function.

    PubMed

    Kakei, Yusuke; Yamazaki, Chiaki; Suzuki, Masashi; Nakamura, Ayako; Sato, Akiko; Ishida, Yosuke; Kikuchi, Rie; Higashi, Shouichi; Kokudo, Yumiko; Ishii, Takahiro; Soeno, Kazuo; Shimada, Yukihisa

    2015-11-01

    Auxin is essential for plant growth and development, this makes it difficult to study the biological function of auxin using auxin-deficient mutants. Chemical genetics have the potential to overcome this difficulty by temporally reducing the auxin function using inhibitors. Recently, the indole-3-pyruvate (IPyA) pathway was suggested to be a major biosynthesis pathway in Arabidopsis thaliana L. for indole-3-acetic acid (IAA), the most common member of the auxin family. In this pathway, YUCCA, a flavin-containing monooxygenase (YUC), catalyzes the last step of conversion from IPyA to IAA. In this study, we screened effective inhibitors, 4-biphenylboronic acid (BBo) and 4-phenoxyphenylboronic acid (PPBo), which target YUC. These compounds inhibited the activity of recombinant YUC in vitro, reduced endogenous IAA content, and inhibited primary root elongation and lateral root formation in wild-type Arabidopsis seedlings. Co-treatment with IAA reduced the inhibitory effects. Kinetic studies of BBo and PPBo showed that they are competitive inhibitors of the substrate IPyA. Inhibition constants (Ki ) of BBo and PPBo were 67 and 56 nm, respectively. In addition, PPBo did not interfere with the auxin response of auxin-marker genes when it was co-treated with IAA, suggesting that PPBo is not an inhibitor of auxin sensing or signaling. We propose that these compounds are a class of auxin biosynthesis inhibitors that target YUC. These small molecules are powerful tools for the chemical genetic analysis of auxin function. PMID:26402640

  16. In Vitro Cytotoxicity and Adaptive Stress Responses to Selected Haloacetic Acid and Halobenzoquinone Water Disinfection Byproducts.

    PubMed

    Procházka, Erik; Escher, Beate I; Plewa, Michael J; Leusch, Frederic D L

    2015-10-19

    The process of disinfecting drinking water inadvertently leads to the formation of numerous disinfection byproducts (DBPs). Some of these are mutagenic, genotoxic, teratogenic, and cytotoxic, as well as potentially carcinogenic both in vivo and in vitro. We investigated the in vitro biological activity of five DBPs: three monohaloacetic acids (monoHAAs) [chloroacetic acid (CAA), bromoacetic acid (BAA), and iodoacetic acid (IAA)] and two novel halobenzoquinones (HBQs) [2,6-dichloro-p-benzoquinone (DCBQ) and 2,6-dibromo-p-benzoquinone]. We focused particularly on cytotoxicity and induction of two adaptive stress response pathways: the oxidative stress responsive Nrf2/ARE and DNA-damage responsive p53 pathways. All five DBPs were cytotoxic to the Caco-2 cell line after a 4 h exposure, and all DBPs induced both of the adaptive stress response pathways, Nrf2/ARE and p53, in the micromolar range, as measured by two β-lactamase-based reporter gene assays. The decreasing order of potency for all three endpoints for the five DBPs was IAA ∼ BAA > DCBQ ∼ DBBQ > CAA. Induction of oxidative stress was previously proposed to be the molecular initiating event (MIE) for both classes of DBPs. However, comparing the levels of activation of the two pathways uncovered that the Nrf2/ARE pathway was the more sensitive endpoint for HAAs, whereas the p53 pathway was more sensitive in the case of HBQs. Therefore, the DNA damage-responsive p53 pathway may be an important piece of information to fill in a gap in the adverse outcome pathway framework for the assessment of HBQs. Finally, we cautiously compared the potential risk of the two novel HBQs using a benchmarking approach to that of the well-studied CAA, which suggested that their relative risk may be lower than that of BAA and IAA. PMID:26327680

  17. Biochemical analyses of indole-3-acetaldoxime-dependent auxin biosynthesis in Arabidopsis

    PubMed Central

    Sugawara, Satoko; Hishiyama, Shojiro; Jikumaru, Yusuke; Hanada, Atsushi; Nishimura, Takeshi; Koshiba, Tomokazu; Zhao, Yunde; Kamiya, Yuji; Kasahara, Hiroyuki

    2009-01-01

    Auxins are hormones that regulate many aspects of plant growth and development. The main plant auxin is indole-3-acetic acid (IAA), whose biosynthetic pathway is not fully understood. Indole-3-acetaldoxime (IAOx) has been proposed to be a key intermediate in the synthesis of IAA and several other indolic compounds. Genetic studies of IAA biosynthesis in Arabidopsis have suggested that 2 distinct pathways involving the CYP79B or YUCCA (YUC) genes may contribute to IAOx synthesis and that several pathways are also involved in the conversion of IAOx to IAA. Here we report the biochemical dissection of IAOx biosynthesis and metabolism in plants by analyzing IAA biosynthesis intermediates. We demonstrated that the majority of IAOx is produced by CYP79B genes in Arabidopsis because IAOx production was abolished in CYP79B-deficient mutants. IAOx was not detected from rice, maize, and tobacco, which do not have apparent CYP79B orthologues. IAOx levels were not significantly altered in the yuc1 yuc2 yuc4 yuc6 quadruple mutants, suggesting that the YUC gene family probably does not contribute to IAOx synthesis. We determined the pathway for conversion of IAOx to IAA by identifying 2 likely intermediates, indole-3-acetamide (IAM) and indole-3-acetonitrile (IAN), in Arabidopsis. When 13C6-labeled IAOx was fed to CYP79B-deficient mutants, 13C6 atoms were efficiently incorporated to IAM, IAN, and IAA. This biochemical evidence indicates that IAOx-dependent IAA biosynthesis, which involves IAM and IAN as intermediates, is not a common but a species-specific pathway in plants; thus IAA biosynthesis may differ among plant species. PMID:19279202

  18. Rapid auxin-induced stimulation of cell wall synthesis in pea internodes

    SciTech Connect

    Kutschera, U.; Briggs, W.R.

    1987-05-01

    The effect of auxin (indole-3-acetic acid; IAA) on growth and incorporation of myo-(2-/sup 3/H(N)) inositol ((/sup 3/H)Ins) into noncellulosic polysacchharides in the cell walls of third internode sections from red light-grown pea seedlings (Pisum sativum L. cv. Alaska) was investigated. Intact section were incubated on (/sup 3/H)Ins for 4 hr to permit uptake of the tracer and then IAA was added. Growth started after a lag phase of 15 min under these conditions. The sections were removed from the tracer and separated into epidermis and cortical cylinder (cortex plus vascular tissue). In the epidermis, IAA-induced stimulation of (/sup 3/H)Ins incorporation started after a lag of 15 min. The amount of incorporation was 15% higher after 30 min and 24% higher after 2 hr than in the control. In the cortical cylinder, IAA-induced stimulation of (/sup 3/H)Ins incorporation started only approx. = 1 hr after adding IAA. The ionophore monensin (20 ..mu..M) inhibited the IAA-induced growth by 95%. Under these conditions, the IAA-induced stimulation of (/sup 3/H)Ins incorporation and the IAA-induced increase in in vivo extensibility of the sections was almost completely inhibited, although oxygen uptake was unaffected. The authors suggest that wall synthesis (as represented by (/sup 3/H)Ins incorporation) and wall loosening (increase in in vivo extensibility) are related processes. The results support the hypothesis that IAA induces growth by rapid simulation of cell wall synthesis in the growth-limiting epidermal cell layer.

  19. The optimum dietary indispensable amino acid pattern for growing Atlantic salmon (Salmo salar L.) fry.

    PubMed

    Rollin, Xavier; Mambrini, Muriel; Abboudi, Tarik; Larondelle, Yvan; Kaushik, Sadasivam J

    2003-11-01

    To determine the optimum indispensable (I) amino acid (AA) balance in Atlantic salmon (Salmo salar L.) fry, a single protocol established for the pig was adapted. The balance was calculated from the reduction in N gain after replacing about 45% of a single IAA by a mixture of dispensable AA in isonitrogenous diets. We confirmed that the mixture of AA simulating the AA pattern of cod-meal protein and gelatine (46:3, w/w) was used with the same efficiency as cod-meal protein and gelatine. From the deletion experiment an optimum balance between the IAA was derived. Expressed relative to lysine = 100, the optimal balance was: arginine 76 (SE 0.2), histidine 28 (SE 2.2), methionine + cystine 64 (SE 1.7), phenylalanine + tyrosine 105 (SE 1.6), threonine 51 (SE 2.4), tryptophan 14 (SE 0.7), valine 59 (SE 1.7). No estimates were made for isoleucine and leucine. Expressed as g/16 g N, the optimal balance was: arginine 4.0 (SE 0.0), histidine 1.5 (SE 0.1), lysine 5.3 (SE 0.2), methionine + cystine 3.4 (SE 0.1), phenylaline + tyrosine 5.6 (SE 0.1), threonine 2.7 (SE 0.1), tryptophan 0.7 (SE 0.0), valine 3.1 (SE 0.1). This AA composition is close to that of the Atlantic salmon whole-body, but using it as an estimation of the IAA requirements may lead to an overestimation of the branched-chain AA requirements and an underestimation of aromatic and S-containing AA requirements. The results are discussed in accordance with the key assumptions associated with the model used (broken-line model, IAA efficiencies and maintenance requirements). PMID:14667180

  20. An Optimized Analytical Method for the Simultaneous Detection of Iodoform, Iodoacetic Acid, and Other Trihalomethanes and Haloacetic Acids in Drinking Water

    PubMed Central

    Jiang, Songhui; Templeton, Michael R.; He, Gengsheng; Qu, Weidong

    2013-01-01

    An optimized method is presented using liquid-liquid extraction and derivatization for the extraction of iodoacetic acid (IAA) and other haloacetic acids (HAA9) and direct extraction of iodoform (IF) and other trihalomethanes (THM4) from drinking water, followed by detection by gas chromatography with electron capture detection (GC-ECD). A Doehlert experimental design was performed to determine the optimum conditions for the five most significant factors in the derivatization step: namely, the volume and concentration of acidic methanol (optimized values  = 15%, 1 mL), the volume and concentration of Na2SO4 solution (129 g/L, 8.5 mL), and the volume of saturated NaHCO3 solution (1 mL). Also, derivatization time and temperature were optimized by a two-variable Doehlert design, resulting in the following optimized parameters: an extraction time of 11 minutes for IF and THM4 and 14 minutes for IAA and HAA9; mass of anhydrous Na2SO4 of 4 g for IF and THM4 and 16 g for IAA and HAA9; derivatization time of 160 min and temperature at 40°C. Under optimal conditions, the optimized procedure achieves excellent linearity (R2 ranges 0.9990–0.9998), low detection limits (0.0008–0.2 µg/L), low quantification limits (0.008–0.4 µg/L), and good recovery (86.6%–106.3%). Intra- and inter-day precision were less than 8.9% and 8.8%, respectively. The method was validated by applying it to the analysis of raw, flocculated, settled, and finished waters collected from a water treatment plant in China. PMID:23613747

  1. Simple in-line postcolumn oxidation and derivatization for the simultaneous analysis of ascorbic and dehydroascorbic acids in foods.

    PubMed

    Bognár, A; Daood, H G

    2000-04-01

    A new analytical procedure for the simultaneous determination of L-ascorbic acid (AA), isoascorbic acid (IAA), L-dehydroascorbic acid (DHAA), and isodehydroascorbic acid (IDHAA) in food by high-performance liquid chromatography (HPLC) is developed. After separation on an HPLC column, an in-line oxidation of AA and IAA to DHAA and IDHAA, respectively, is performed on a short column of activated charcoal. The dehydroascorbic acids are derivatized with a 1,2-phenylenediamine solution in a heated capillary Tefzel reactor into fluorescent quinoxaline compounds and monitored fluorometrically. The chromatographic method provides good separation of LAA, LDHAA, and their diastereoisomers in a relatively short time (-10 min). After optimization of postcolumn derivatization conditions, calibration runs and recovery tests are performed. The fluorescent response in terms of peak area is highly proportional to the concentration of all derivatives examined over a range of 0.1 to 100 microg/mL solution for LAA, LDHAA, IAA, and IDHAA. Recoveries were in the range of 97 to 103%. The detection limit is 0.1 mg of each ascorbic acid derivative per 100 g food. A wide variety of foods (fruits, fruit juices, vegetables, vegetable products, milk, liver, and sausage) are analyzed by the developed procedure. The Vitamin C (LAA and LDHA) contents determined according to the present analytical method are in the same order of magnitude as the result of precolumn derivatization and the fluorometric methods. The described method is a highly specific procedure for determining Vitamin C in food. It is simple to handle, only slightly susceptible to disturbance, perfectly suitable for serial determinations, and yields reproducible results. PMID:10766483

  2. Effects of acetic acid on the viability of Ascaris lumbricoides eggs

    PubMed Central

    Beyhan, Yunus E.; Yilmaz, Hasan; Hokelek, Murat

    2016-01-01

    Objectives: To investigate the effects of acetic acid on durable Ascaris lumbricoides (A. lumbricoides) eggs to determine the effective concentration of vinegar and the implementation period to render the consumption of raw vegetables more reliable. Methods: This experimental study was performed in May 2015 in the Parasitology Laboratory, Faculty of Medicine, Yuzuncu Yil University, Van, Turkey. The A. lumbricoides eggs were divided into 2 groups. Eggs in the study group were treated with 1, 3, 5, and 10% acetic acid concentrations, and eggs in the control group were treated with Eosin. The eggs’ viability was observed at the following points in time during the experiment: 0, 10, 15, 20, 30, 45, and 60 minutes. Results: The 1% acetic acid was determined insufficient on the viability of Ascaris eggs. At the 30th minute, 3% acetic acid demonstrated 95% effectiveness, and at 5% concentration, all eggs lost their viability. Treatment of acetic acid at the ratio of 4.8% in 30 minutes, or a ratio of 4.3% in 60 minutes is required for full success of tretment. Conclusion: Since Ascaris eggs have 3 layers and are very resistant, the acetic acid concentration, which can be effective on these eggs are thought to be effective also on many other parasitic agents. In order to attain an active protection, after washing the vegetables, direct treatment with a vinegar containing 5% acetic acid for 30 minutes is essential. PMID:26905351

  3. 5 prime -Azido-(3,6- sup 3 H sub 2 )-1-naphthylphthalamic acid, a photoactivatable probe for naphthylphthalamic acid receptor proteins from higher plants: Identification of a 23-kDa protein from maize coleoptile plasma membranes

    SciTech Connect

    Zettl, R.; Feldwisch, J.; Schell, J.; Palme, K. ); Boland, W. )

    1992-01-15

    1-Naphthylphthalamic acid (NPA) is a specific inhibitor of polar auxin transport that blocks carrier mediated auxin efflux from plant cells. To allow identification of the NPA receptor thought to be part of the auxin efflux carrier, the authors have synthesized a tritiated, photolabile NPA analogue, 5{prime}-azido-(3,6-{sup 3}H{sub 2})NPA (({sup 3}H{sub 2})N{sub 3}NPA). This analogue was used to identify NPA-binding proteins in fractions highly enriched for plasma membrane vesicles isolated from maize coleoptiles (Zea mays L.). Competition studies showed that binding of ({sup 3}H{sub 2})N{sub 3}NPA to maize plasma membrane vesicles was blocked by nonradioactive NPA but not by benzoic acid. After incubation of plasma membrane vesicles with ({sup 3}H{sub 2})N{sub 3}NPA and exposure to UV light, they observed specific photoaffinity labeling of a protein with an apparent molecular mass of 23 kDa. Pretreatment of the plasma membrane vesicles with indole-3-acetic acid or with the auxin-transport inhibitors NPA and 2,3,5-triiodobenzoic acid strongly reduced specific labeling of this protein. This 23-kDa protein was also labeled by addition of 5-azido-(7-{sup 3}H)indole-3-acetic acid to plasma membranes prior to exposure to UV light. The 23-kDa protein was solubilized from plasma membranes by 1% Triton X-100. The possibility that this 23-kDa polypeptide is part of the auxin efflux carrier system is discussed.

  4. Conference on Instrumental Activation Analysis: IAA 89

    NASA Astrophysics Data System (ADS)

    Vobecky, M.; Obrusnik, I.

    1989-05-01

    The proceedings contain 40 abstracts of papers all of which have been incorporated in INIS. The papers were centred on the applications of radioanalytical methods, especially on neutron activation analysis, x ray fluorescence analysis, PIXE analysis and tracer techniques in biology, medicine and metallurgy, measuring instruments including microcomputers, and data processing methods.

  5. Phytotoxical effect of Lepidium draba L. extracts on the germination and growth of monocot (Zea mays L.) and dicot (Amaranthus retroflexus L.) seeds.

    PubMed

    Kaya, Yusuf; Aksakal, Ozkan; Sunar, Serap; Erturk, Filiz Aygun; Bozari, Sedat; Agar, Guleray; Erez, Mehmet Emre; Battal, Peyami

    2015-03-01

    Laboratory experiments were performed to determine phytotoxic potentials of white top (Lepidium draba) methanol extracts (root, stem and leaf) on germination and early growth of corn (Zea mays) and redroot pigweed (Amaranthus retroflexus). Furthermore, the effects of different methanol extracts of L. draba on the phytohormone (indole-3-acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA) and zeatin) levels of corn and redroot pigweed were investigated. It was observed that all concentrations of methanol extracts of root, stem and leaf of L. draba inhibited germination, radicle and plumule elongation when compared with the respective controls. Besides this, the degree of inhibition was increased in concert with increasing concentrations of extracts used. On the other hand, phytohormone levels changed with the application of different extract concentrations. Comparing with the control, the GA levels significantly decreased while the ABA levels increased in all the application groups. Zeatin and IAA levels showed changes depending upon the applied extracts and concentrations. PMID:23293131

  6. Amino acids

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002222.htm Amino acids To use the sharing features on this page, please enable JavaScript. Amino acids are organic compounds that combine to form proteins . ...

  7. Mefenamic Acid

    MedlinePlus

    Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. ...

  8. Aminocaproic Acid

    MedlinePlus

    Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

  9. Ascorbic Acid

    MedlinePlus

    Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C in ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops to ...

  10. Acid mucopolysaccharides

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003368.htm Acid mucopolysaccharides To use the sharing features on this page, please enable JavaScript. Acid mucopolysaccharides is a test that measures the amount ...

  11. Ethacrynic Acid

    MedlinePlus

    Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

  12. Effects of temperature and sink activity on the transport of (14)C-labelled indol-3yl-acetic acid in the intact pea plant (Pisum sativum L.).

    PubMed

    Eliezer, J; Morris, D A

    1979-12-01

    The velocity and intensity of basipetal transport of (14)C-labelled indol-3yl-acetic acid (IAA) applied to the apical bud of the intact pea plant were influenced by the temperature to which the stem was exposed and were not influenced by changes in the temperature of the root system when this was controlled independently between 5°C and 35°C. The velocity of transport increased steadily with temperature to a maximum in excess of 35°C and then fell sharply with further increase in temperature. The Q10 for velocity, determined from Arrhenius plots, was low (ca. 1.3). Transport intensity increased to a maximum at about 25°C (Q10=2.2) and then declined gradually with further increase in temperature. It is suggested that transport velocity and transport intensity are controlled independently.The characteristics of auxin transport through the stem were not affected by removal of the root system, or by the withdrawl of root aeration. Labelled IAA did not pass a region of the stem cooled to about 1.0°C, or through a narrow zone of stem tissue killed by heat treatment. In the latter case the heat treatment was shown not to interfere with the upward transport of water in the xylem. Labelled IAA continued to move into, and to accumulate in, the tissues immediately above a cooled or heat-killed region of the stem. It was concluded that the long-distance basipetal transport of auxin through the stem of the intact plant is driven by the transporting cells themselves and is independent of the activity of sinks for the transported auxin.The fronts of the observed tracer profiles in the stem were closely fitted by error function diffusion analogue curves. However, diffusion of IAA alone could not account for the observed characteristics of the transport and it is suggested that the curvilinear fronts of the profiles resulted from a diffusive mixing of exogenous IAA (or IAA-carrier complexes) with endogenous IAA already in the transport pathway. PMID:24311035

  13. Valproic Acid

    MedlinePlus

    Valproic acid is used alone or with other medications to treat certain types of seizures. Valproic acid is also used to treat mania (episodes of ... to relieve headaches that have already begun. Valproic acid is in a class of medications called anticonvulsants. ...

  14. Shoot-derived abscisic acid promotes root growth.

    PubMed

    McAdam, Scott A M; Brodribb, Timothy J; Ross, John J

    2016-03-01

    The phytohormone abscisic acid (ABA) plays a major role in regulating root growth. Most work to date has investigated the influence of root-sourced ABA on root growth during water stress. Here, we tested whether foliage-derived ABA could be transported to the roots, and whether this foliage-derived ABA had an influence on root growth under well-watered conditions. Using both application studies of deuterium-labelled ABA and reciprocal grafting between wild-type and ABA-biosynthetic mutant plants, we show that both ABA levels in the roots and root growth in representative angiosperms are controlled by ABA synthesized in the leaves rather than sourced from the roots. Foliage-derived ABA was found to promote root growth relative to shoot growth but to inhibit the development of lateral roots. Increased root auxin (IAA) levels in plants with ABA-deficient scions suggest that foliage-derived ABA inhibits root growth through the root growth-inhibitor IAA. These results highlight the physiological and morphological importance, beyond the control of stomata, of foliage-derived ABA. The use of foliar ABA as a signal for root growth has important implications for regulating root to shoot growth under normal conditions and suggests that leaf rather than root hydration is the main signal for regulating plant responses to moisture. PMID:26514625

  15. Root-Shoot Signaling crosstalk involved in the shoot growth promoting action of rhizospheric humic acids

    PubMed Central

    Olaetxea, Maite; Mora, Verónica; García, Andrés Calderin; Santos, Leandro Azevedo; Baigorri, Roberto; Fuentes, Marta; Garnica, María; Berbara, Ricardo Luis Louro; Zamarreño, Angel Maria; Garcia-Mina, Jose M.

    2016-01-01

    ABSTRACT Numerous studies have shown the ability of humic substances to improve plant development. This action is normally reflected in an enhancement of crop yields and quality. However, the mechanisms responsible for this action of humic substances remain rather unknown. Our studies have shown that the shoot promoting action of sedimentary humic acids is dependent of its ability to increase root hydraulic conductivity through signaling pathways related to ABA, which in turn is affected in roots by humic acids in an IAA-NO dependent way. Furthermore, these studies also indicate that the primary action of humic acids in roots might also be physical, resulting from a transient mild stress caused by humic acids associated with a fouling-cleaning cycle of wall cell pores. Finally the role of alternative signal molecules, such as ROS, and corresponding signaling pathways are also discussed and modeled in the context of the above-mentioned framework. PMID:26966789

  16. Cloning and characterization of indolepyruvate decarboxylase from Methylobacterium extorquens AM1.

    PubMed

    Fedorov, D N; Doronina, N V; Trotsenko, Yu A

    2010-12-01

    For the first time for methylotrophic bacteria an enzyme of phytohormone indole-3-acetic acid (IAA) biosynthesis, indole-3-pyruvate decarboxylase (EC 4.1.1.74), has been found. An open reading frame (ORF) was identified in the genome of facultative methylotroph Methylobacterium extorquens AM1 using BLAST. This ORF encodes thiamine diphosphate-dependent 2-keto acid decarboxylase and has similarity with indole-3-pyruvate decarboxylases, which are key enzymes of IAA biosynthesis. The ORF of the gene, named ipdC, was cloned into overexpression vector pET-22b(+). Recombinant enzyme IpdC was purified from Escherichia coli BL21(DE3) and characterized. The enzyme showed the highest k(cat) value for benzoylformate, albeit the indolepyruvate was decarboxylated with the highest catalytic efficiency (k(cat)/K(m)). The molecular mass of the holoenzyme determined using gel-permeation chromatography corresponds to a 245-kDa homotetramer. An ipdC-knockout mutant of M. extorquens grown in the presence of tryptophan had decreased IAA level (46% of wild type strain). Complementation of the mutation resulted in 6.3-fold increase of IAA concentration in the culture medium compared to that of the mutant strain. Thus involvement of IpdC in IAA biosynthesis in M. extorquens was shown. PMID:21314613

  17. Development of the Poplar-Laccaria bicolor Ectomycorrhiza Modifies Root Auxin Metabolism, Signaling, and Response.

    PubMed

    Vayssières, Alice; Pěnčík, Ales; Felten, Judith; Kohler, Annegret; Ljung, Karin; Martin, Francis; Legué, Valérie

    2015-09-01

    Root systems of host trees are known to establish ectomycorrhizae (ECM) interactions with rhizospheric fungi. This mutualistic association leads to dramatic developmental modifications in root architecture, with the formation of numerous short and swollen lateral roots ensheathed by a fungal mantle. Knowing that auxin plays a crucial role in root development, we investigated how auxin metabolism, signaling, and response are affected in poplar (Populus spp.)-Laccaria bicolor ECM roots. The plant-fungus interaction leads to the arrest of lateral root growth with simultaneous attenuation of the synthetic auxin response element DR5. Measurement of auxin-related metabolites in the free-living partners revealed that the mycelium of L. bicolor produces high concentrations of the auxin indole-3-acetic acid (IAA). Metabolic profiling showed an accumulation of IAA and changes in the indol-3-pyruvic acid-dependent IAA biosynthesis and IAA conjugation and degradation pathways during ECM formation. The global analysis of auxin response gene expression and the regulation of AUXIN SIGNALING F-BOX PROTEIN5, AUXIN/IAA, and AUXIN RESPONSE FACTOR expression in ECM roots suggested that symbiosis-dependent auxin signaling is activated during the colonization by L. bicolor. Taking all this evidence into account, we propose a model in which auxin signaling plays a crucial role in the modification of root growth during ECM formation. PMID:26084921

  18. Exogenous jasmonic acid induces stress tolerance in tobacco (Nicotiana tabacum) exposed to imazapic.

    PubMed

    Kaya, Armagan; Doganlar, Zeynep Banu

    2016-02-01

    Jasmonic acid (JA) is one of the important phytohormones, regulating the stress responses as well as plant growth and development. The aim of this study is to determine the effects of exogenous JA application on stress responses of tobacco plant exposed to imazapic. In this study, phytotoxic responses resulting from both imazapic and imazapic combined with JA treatment are investigated comparatively for tobacco plants. For plants treated with imazapic at different concentrations (0.030, 0.060 and 0.120mM), antioxidant enzyme activities (catalase, ascorbate peroxidase, glutathione S-transferase and glutathione reductase), carotenoids, glutathione and malondialdehyte (MDA) contents, jasmonic acid, abscisic acid and indole-3-acetic acid levels as well as herbicide residue amounts on leaves increased in general compared to the control group. In the plants treated with 45µM jasmonic acid, pigment content, antioxidant activity and phytohormone level increased whereas MDA content and the amount of herbicidal residue decreased compared to the non-treated plants. Our findings show that imazapic treatment induces some phytotoxic responses on tobacco leaves and that exogenous jasmonic acid treatment alleviates the negative effects of herbicide treatment by regulating these responses. PMID:26629659

  19. Fatty acids - trans fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The data supporting a negative effect of dietary trans fatty acids on cardiovascular disease risk is consistent. The primary dietary sources of trans fatty acids include partially hydrogenated fat and rudiment fat. The adverse effect of trans fatty acids on plasma lipoprotein profiles is consisten...

  20. Anaerobic Metabolism of Indoleacetate

    PubMed Central

    Ebenau-Jehle, Christa; Thomas, Markus; Scharf, Gernot; Kockelkorn, Daniel; Knapp, Bettina; Schühle, Karola; Heider, Johann

    2012-01-01

    The anaerobic metabolism of indoleacetate (indole-3-acetic acid [IAA]) in the denitrifying betaproteobacterium Azoarcus evansii was studied. The strain oxidized IAA completely and grew with a generation time of 10 h. Enzyme activities that transformed IAA were present in the soluble cell fraction of IAA-grown cells but were 10-fold downregulated in cells grown on 2-aminobenzoate or benzoate. The transformation of IAA did not require molecular oxygen but required electron acceptors like NAD+ or artificial dyes. The first products identified were the enol and keto forms of 2-oxo-IAA. Later, polar products were observed, which could not yet be identified. The first steps likely consist of the anaerobic hydroxylation of the N-heterocyclic pyrrole ring to the enol form of 2-oxo-IAA, which is catalyzed by a molybdenum cofactor-containing dehydrogenase. This step is probably followed by the hydrolytic ring opening of the keto form, which is catalyzed by a hydantoinase-like enzyme. A comparison of the proteome of IAA- and benzoate-grown cells identified IAA-induced proteins. Owing to the high similarity of A. evansii with strain EbN1, whose genome is known, we identified a cluster of 14 genes that code for IAA-induced proteins involved in the early steps of IAA metabolism. These genes include a molybdenum cofactor-dependent dehydrogenase of the xanthine oxidase/aldehyde dehydrogenase family, a hydantoinase, a coenzyme A (CoA) ligase, a CoA transferase, a coenzyme B12-dependent mutase, an acyl-CoA dehydrogenase, a fusion protein of an enoyl-CoA hydratase and a 3-hydroxyacyl-CoA dehydrogenase, a beta-ketothiolase, and a periplasmic substrate binding protein for ABC transport as well as a transcriptional regulator of the GntR family. Five predicted enzymes form or act on CoA thioesters, indicating that soon after the initial oxidation of IAA and possibly ring opening, CoA thioesters are formed, and the carbon skeleton is rearranged, followed by a CoA-dependent thiolytic

  1. Analysis of acidic endogenous phytohormones in grapes by using online solid-phase extraction coupled with LC-MS/MS.

    PubMed

    Yu, Jian-Na; Meng, Qing-Yan; Liu, Wen-Jie; Lu, Ya-Ling; Ren, Xiao-Lin

    2014-10-01

    Phytohormones play important roles in regulating numerous plant physiological and developmental processes, even during the postharvest storage period. In order to determine the functions and changes of gibberellins acid (GA3), indoleacetic acid (IAA), abscisic acid (ABA), indolebutyric acid (IBA) and jasmonic acid (JA) in grape berries during storage, an ultrasensitive method based on direct injection online solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Grape berries were extracted with cold methanol. After centrifugation, the supernatants were concentrated with a vacuum centrifugal concentrator and injected into an online solid-phase extraction column. After the cleanup procedure, the analytes were determined by LC-MS/MS. The results showed that the linearity of the proposed method was 10-210 µg kg(-1) for ABA, 20-200 µg kg(-1) for IBA, 15-320 µg kg(-1) for IAA, 20-320 µg kg(-1) for GA3 and 3.0-90.0 µg kg(-1) for JA. The limits of detection of the method were 0.71, 2.79, 0.94, 0.39 and 0.57 µg kg(-1), respectively. The proposed method was successfully applied to the analysis of endogenous phytohormones in grape berries during the postharvest storage period. PMID:24200641

  2. High-frequency in vitro plantlet regeneration from apical bud as a novel explant of Carum copticum L.

    PubMed Central

    Salehi, Mansoureh; Hosseini, Bahman; Jabbarzadeh, Zohreh

    2014-01-01

    Objective To develop an in vitro regeneration system to increase the recovery of Carum copticum L. plantlets as a part of developing a metabolic engineering program. Methods The efficacy of different concentrations and combinations of 6-benzyladenine, indole-3-acetic acid and indole butyric acid on direct shoot regeneration and rooting of ajowan from apical bud explants were assessed. All explants were cultured on Murashige and Skoog (MS) medium supplemented with different combinations of 6-benzyl amino purine (BAP) (0, 2.2, 4.4, 8.8 µmol/L) and indole-3-acetic acid (IAA) (0, 0.5, 1.1, 2.2 µmol/L). Results The maximum shoot regeneration frequency (97.5%) and the highest number of shoots produced from apical buds (34 shoots per explant) were obtained on MS medium fortified with BAP (4.4 µmol/L) and IAA (0.5 µmol/L). Low shoot regeneration frequency was observed in BAP free treatments. The effects of different strengths of MS medium and various concentrations of IAA and indole-3- butyric acid on rooting rate, length and average number of roots were also investigated. Application of indole-3- butyric acid (6 µmol/L) in full-strength MS medium, was more effective than IAA and resulted in highest shoot regeneration frequency with the rooting rate of 100% and highest mean number of roots per shoot (41.8). The rooted plantlets were acclimatized successfully in greenhouse conditions with a survival rate of 90%. Conclusion In this study, a simple and reliable regeneration and acclimatization protocol for Carum copticum has been presented. This protocol can be found very advantageous for a variety of purposes, including mass multiplication of Carum species, medicinal plant breeding studies and transgenic plant production. PMID:25183122

  3. Studies on the medicinal properties of Solanum chrysotrichum in tissue culture: I. Callus formation and plant induction from axillary buds.

    PubMed

    Villarreal, M L; Muñoz, J

    1991-01-01

    A tissue culture method is described for micropropagation and callus formation from Solanum chrysotricum axillary bud explants in Murashige and Skoog's (MS) medium, supplemented with various growth regulators. Induction of rooted plants were initiated only when indol-3 acetic acid (IAA) was present as an auxin in combination with either of two cytokinins: kinetin (KN) or benzyladenine (BA); however, the combination of IAA (0.1 mg.lt.-1) + BA (0.2 mg.lt.-1) was found to be best suited for morphogenesis purposes. Alternatively, callus tissue formation was influenced in presence of naphthalene acetic acid; which in combination with kinetin (NAA 0.1 mg.lt.-1 + KN 0.2 mg.lt.-1) exhibit the best response studied. The plant material obtained by this procedure is proposed for pharmacological and chemical studies of this important antimycotic plant remedy. PMID:1819987

  4. Valproic Acid Induces Antimicrobial Compound Production in Doratomyces microspores

    PubMed Central

    Zutz, Christoph; Bacher, Markus; Parich, Alexandra; Kluger, Bernhard; Gacek-Matthews, Agnieszka; Schuhmacher, Rainer; Wagner, Martin; Rychli, Kathrin; Strauss, Joseph

    2016-01-01

    One of the biggest challenges in public health is the rising number of antibiotic resistant pathogens and the lack of novel antibiotics. In recent years there is a rising focus on fungi as sources of antimicrobial compounds due to their ability to produce a large variety of bioactive compounds and the observation that virtually every fungus may still contain yet unknown so called “cryptic,” often silenced, compounds. These putative metabolites could include novel bioactive compounds. Considerable effort is spent on methods to induce production of these “cryptic” metabolites. One approach is the use of small molecule effectors, potentially influencing chromatin landscape in fungi. We observed that the supernatant of the fungus Doratomyces (D.) microsporus treated with valproic acid (VPA) displayed antimicrobial activity against Staphylococcus (S.) aureus and two methicillin resistant clinical S. aureus isolates. VPA treatment resulted in enhanced production of seven antimicrobial compounds: cyclo-(L-proline-L-methionine) (cPM), p-hydroxybenzaldehyde, cyclo-(phenylalanine-proline) (cFP), indole-3-carboxylic acid, phenylacetic acid (PAA) and indole-3-acetic acid. The production of the antimicrobial compound phenyllactic acid was exclusively detectable after VPA treatment. Furthermore three compounds, cPM, cFP, and PAA, were able to boost the antimicrobial activity of other antimicrobial compounds. cPM, for the first time isolated from fungi, and to a lesser extent PAA, are even able to decrease the minimal inhibitory concentration of ampicillin in MRSA strains. In conclusion we could show in this study that VPA treatment is a potent tool for induction of “cryptic” antimicrobial compound production in fungi, and that the induced compounds are not exclusively linked to the secondary metabolism. Furthermore this is the first discovery of the rare diketopiperazine cPM in fungi. Additionally we could demonstrate that cPM and PAA boost antibiotic activity

  5. Auxin biosynthesis and storage forms

    PubMed Central

    Strader, Lucia C.

    2013-01-01

    The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development. PMID:23580748

  6. Active food packaging based on molecularly imprinted polymers: study of the release kinetics of ferulic acid.

    PubMed

    Otero-Pazos, Pablo; Rodríguez-Bernaldo de Quirós, Ana; Sendón, Raquel; Benito-Peña, Elena; González-Vallejo, Victoria; Moreno-Bondi, M Cruz; Angulo, Immaculada; Paseiro-Losada, Perfecto

    2014-11-19

    A novel active packaging based on molecularly imprinted polymer (MIP) was developed for the controlled release of ferulic acid. The release kinetics of ferulic acid from the active system to food simulants (10, 20, and 50% ethanol (v/v), 3% acetic acid (w/v), and vegetable oil), substitutes (95% ethanol (v/v) and isooctane), and real food samples at different temperatures were studied. The key parameters of the diffusion process were calculated by using a mathematical modeling based on Fick's second law. The ferulic acid release was affected by the temperature as well as the percentage of ethanol of the simulant. The fastest release occurred in 95% ethanol (v/v) at 20 °C. The diffusion coefficients (D) obtained ranged between 1.8 × 10(-11) and 4.2 × 10(-9) cm(2)/s. A very good correlation between experimental and estimated data was obtained, and consequently the model could be used to predict the release of ferulic acid into food simulants and real food samples. PMID:25369799

  7. Exogenous Ghrelin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats.

    PubMed

    Matuszyk, Aleksandra; Ceranowicz, Piotr; Warzecha, Zygmunt; Cieszkowski, Jakub; Ceranowicz, Dagmara; Gałązka, Krystyna; Bonior, Joanna; Jaworek, Jolanta; Bartuś, Krzysztof; Gil, Krzysztof; Olszanecki, Rafał; Dembiński, Artur

    2016-01-01

    Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis. PMID:27598133

  8. Enzymatic synthesis of bile acid derivatives and biological evaluation against Trypanosoma cruzi.

    PubMed

    García Liñares, Guadalupe; Antonela Zígolo, M; Simonetti, Leandro; Longhi, Silvia A; Baldessari, Alicia

    2015-08-01

    Enzyme catalysis was applied to synthesize derivatives of three bile acids and their biological activity was evaluated as growth inhibitors of the protozoan Trypanosoma cruzi. Twelve mono-, diacetyl and ester derivatives of deoxycholic, chenodeoxycholic and lithocholic acid, seven of them new compounds, were obtained through lipase-catalyzed acetylation, esterification and alcoholysis reactions in very good to excellent yield and a highly regioselective way. Among them, acetylated ester products, in which the lipase catalyzed both reactions in one-pot, were obtained. The influence of various reaction parameters in the enzymatic reactions, such as enzyme source, acylating agent/substrate ratio, enzyme/substrate ratio, solvent and temperature, was studied. Some of the evaluated compounds showed a remarkable activity as Trypanosoma cruzi growth inhibitors, obtaining the best results with ethyl chenodeoxycholate 3-acetate and chenodeoxycholic acid 3,7-diacetate, which showed IC50: 8.6 and 22.8 μM, respectively. In addition, in order to shed light to bile acids behavior in enzymatic reactions, molecular modeling was applied to some derivatives. The advantages showed by the enzymatic methodology, such as mild reaction conditions and low environmental impact, make the biocatalysis a convenient way to synthesize these bile acid derivatives with application as potential antiparasitic agents. PMID:26072173

  9. Role of chloride ions in the promotion of auxin-induced growth of maize coleoptile segments

    PubMed Central

    Burdach, Zbigniew; Kurtyka, Renata; Siemieniuk, Agnieszka; Karcz, Waldemar

    2014-01-01

    Background and Aims The mechanism of auxin action on ion transport in growing cells has not been determined in detail. In particular, little is known about the role of chloride in the auxin-induced growth of coleoptile cells. Moreover, the data that do exist in the literature are controversial. This study describes experiments that were carried out with maize (Zea mays) coleoptile segments, this being a classical model system for studies of plant cell elongation growth. Methods Growth kinetics or growth and pH changes were recorded in maize coleoptiles using two independent measuring systems. The growth rate of the segments was measured simultaneously with medium pH changes. Membrane potential changes in parenchymal cells of the segments were also determined for chosen variants. The question of whether anion transport is involved in auxin-induced growth of maize coleoptile segments was primarily studied using anion channel blockers [anthracene-9-carboxylic acid (A-9-C) and 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid (DIDS)]. In addition, experiments in which KCl was replaced by KNO3 were also performed. Key Results Both anion channel blockers, added at 0·1 mm, diminished indole-3-acetic acid (IAA)-induced elongation growth by ∼30 %. Medium pH changes measured simultaneously with growth indicated that while DIDS stopped IAA-induced proton extrusion, A-9-C diminished it by only 50 %. Addition of A-9-C to medium containing 1 mm KCl did not affect the characteristic kinetics of IAA-induced membrane potential changes, while in the presence of 10 mm KCl the channel blocker stopped IAA-induced membrane hyperpolarization. Replacement of KCl with KNO3 significantly decreased IAA-induced growth and inhibited proton extrusion. In contrast to the KCl concentration, the concentration of KNO3 did not affect the growth-stimulatory effect of IAA. For comparison, the effects of the cation channel blocker tetraethylammonium chloride (TEA-Cl) on IAA-induced growth and

  10. Acid Deposition

    EPA Science Inventory

    This indicator presents acid deposition trends in the contiguous U.S. from 1989 to 2007. Data are broken down by wet and dry deposition and deposition of nitrogen and sulfur compounds. Acid deposition is particularly damaging to lakes, streams, and forests and the plants and a...

  11. Acid rain

    SciTech Connect

    White, J.C. )

    1988-01-01

    This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

  12. Acid rain

    SciTech Connect

    Elsworth, S.

    1985-01-01

    This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

  13. Gravity-stimulated changes in auxin and invertase gene expression in maize pulvinal cells

    NASA Technical Reports Server (NTRS)

    Long, Joanne C.; Zhao, Wei; Rashotte, Aaron M.; Muday, Gloria K.; Huber, Steven C.; Brown, C. S. (Principal Investigator)

    2002-01-01

    Maize (Zea mays) stem gravitropism involves differential elongation of cells within a highly specialized region, the stem internodal pulvinus. In the present study, we investigated factors that control gravitropic responses in this system. In the graviresponding pulvinus, hexose sugars (D-Glc and D-Fru) accumulated asymmetrically across the pulvinus. This correlated well with an asymmetric increase in acid invertase activity across the pulvinus. Northern analyses revealed asymmetric induction of one maize acid invertase gene, Ivr2, consistent with transcriptional regulation by gravistimulation. Several lines of evidence indicated that auxin redistribution, as a result of polar auxin transport, is necessary for gravity-stimulated Ivr2 transcript accumulation and differential cell elongation across the maize pulvinus. First, the auxin transport inhibitor, N-1-naphthylphthalamic acid, inhibited gravistimulated curvature and Ivr2 transcript accumulation. Second, a transient gradient of free indole-3-acetic acid (IAA) across the pulvinus was apparent shortly after initiation of gravistimulation. This temporarily free IAA gradient appears to be important for d