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Sample records for abscisic acid

  1. Abscisic Acid Signaling in Plants

    Vaňková, Radomíra

    NEW YORK : Springer, 2012 - (Ahmad, P.; Prasad, M.), s. 359-368 ISBN 978-1-4614-0633-4 R&D Projects: GA ČR GA522/09/2058 Institutional research plan: CEZ:AV0Z50380511 Keywords : PP2C * PYR/PYL/RCAR proteins * Abscisic acid Subject RIV: ED - Physiology

  2. Ex vitro transfer and abscisic acid

    Pospíšilová, Jana; Synková, Helena; Haisel, Daniel; Vágner, Martin; Baťková, Petra

    Faro, 2007. s. 33-33. [International Symposium on Acclimatization and Establishment of Micropropagated Plants /3./. 12.09.2007-15.09.2007, University of Algarve] R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : abscisic acid * antioxidants * ex vitro transfer * in vitro growth * stomata * photoinhibition * xanthophyll cycl Subject RIV: ED - Physiology

  3. Presence of abscisic acid, a phytohormone, in the mammalian brain

    This paper reports the presence of abscisic acid, one of the most important phytohormones, in the central nervous system of pigs and rats. The identification of this hormone in brain was made after extensive purification by using a radioimmunoassay that is very specific for (+)-cis-abscisic acid. The final product of purification from mammalian brain has the same properties as authentic abscisic acid: it crossreacts in the radioimmunoassay for the phytohormone and it has the same retention properties and the same gas chromatography/mass spectrometry characteristics. Moreover, like (+)-cis-abscisic acid itself, the brain factor inhibits stomatal apertures of abaxial epidermis strips of Setcreasea purpurea Boom (Commelinaceae). The presence of abscisic acid conjugates that are present in plants has also been identified in brain

  4. Presence of abscisic acid, a phytohormone, in the mammalian brain

    Le Page-Degivry, M.T.; Bidard, J.N.; Rouvier, E.; Bulard, C.; Lazdunski, M.

    1986-02-01

    This paper reports the presence of abscisic acid, one of the most important phytohormones, in the central nervous system of pigs and rats. The identification of this hormone in brain was made after extensive purification by using a radioimmunoassay that is very specific for (+)-cis-abscisic acid. The final product of purification from mammalian brain has the same properties as authentic abscisic acid: it crossreacts in the radioimmunoassay for the phytohormone and it has the same retention properties and the same gas chromatography/mass spectrometry characteristics. Moreover, like (+)-cis-abscisic acid itself, the brain factor inhibits stomatal apertures of abaxial epidermis strips of Setcreasea purpurea Boom (Commelinaceae). The presence of abscisic acid conjugates that are present in plants has also been identified in brain.

  5. Roles of Abscisic Acid in Fruit Ripening

    Sutthiwal SETHA

    2012-12-01

    Full Text Available Abscisic acid (ABA is a plant growth regulator, and it plays a variety of important roles throughout a plant’s life cycle. These roles include seed development and dormancy, plant response to environmental stresses, and fruit ripening. ABA concentration is very low in unripe fruit, but it increases as a fruit ripens, so it is therefore believed that ABA plays an important role in regulating the rate of fruit ripening. This article reviews the effect of ABA on ripening and quality of climacteric and non-climacteric fruits. The effects of ABA application on fruit ripening are subsequently discussed. Moreover, it is found that during fruit ripening, ABA also contributes to other functions, such as ethylene and respiratory metabolism, pigment and color changes, phenolic metabolism and nutritional contents, cell wall metabolism and fruit softening, and sugar and acid metabolism. These processes are all discussed as part of the relationship between ABA and fruit ripening, and the possibilities for its commercial application and use are highlighted.

  6. GENETIC ANALYSIS OF ABSCISIC ACID BIOSYNTHESIS

    MCCARTY D R

    2012-01-10

    The carotenoid cleavage dioxygenases (CCD) catalyze synthesis of a variety of apo-carotenoid secondary metabolites in plants, animals and bacteria. In plants, the reaction catalyzed by the 11, 12, 9-cis-epoxy carotenoid dioxygenase (NCED) is the first committed and key regulated step in synthesis of the plant hormone, abscisic acid (ABA). ABA is a key regulator of plant stress responses and has critical functions in normal root and seed development. The molecular mechanisms responsible for developmental control of ABA synthesis in plant tissues are poorly understood. Five of the nine CCD genes present in the Arabidopsis genome encode NCED's involved in control of ABA synthesis in the plant. This project is focused on functional analysis of these five AtNCED genes as a key to understanding developmental regulation of ABA synthesis and dissecting the role of ABA in plant development. For this purpose, the project developed a comprehensive set of gene knockouts in the AtNCED genes that facilitate genetic dissection of ABA synthesis. These mutants were used in combination with key molecular tools to address the following specific objectives: (1) the role of ABA synthesis in root development; (2) developmental control of ABA synthesis in seeds; (3) analysis of ATNCED over-expressers; (4) preliminary crystallography of the maize VP14 protein.

  7. Incorporation of oxygen into abscisic acid and phaseic acid for molecular oxygen

    Abscisic acid accumulates in detached, wilted leaves of Xanthium strumariu. When these leaves are subsequently rehydrated, phaseic acid, a catabolite of abscisic acid, accumulates. Analysis by gas chromatography-mass spectrometry of phaseic acid isolated from stressed and subsequently rehydrated leaves placed in an atmosphere containing 20% 18O2 and 80% N2 indicates that one atom of 18O is incorporated in the 6'-hydroxymethyl group of phaseic acid. This suggests that the enzyme that converts abscisic acid to phaseic acid is an oxygenase. Analysis by gas chromatography-mass spectrometry of abscisic acid isolated from stressed leaves kept in an atmosphere containing 18O2 indicates that one atom of 18O is presented in the carboxyl group of abscisic acid. Thus, when abscisic acid accumulates in water-streesed leaves, only one of the four oxygens present in the abscisic acid molecule is derived from molecular oxygen. This suggest that either (a) the oxygen present in the 1'-, 4'-, and one of the two oxygens at the 1-position of abscisic acid arise from water, or (b) there exists a stored precursor with oxygen atoms already present in the 1'- and 4'-positions of abscisic acid which is converted to abscisic acid under conditions of water stress. 17 references, 2 figures, 1 tables

  8. Radioimmunoassay for free and bound forms of abscisic acid

    A radioimmunoassay (RIA) for the quanitation of abscisic acid (ABA) has been developed. The assay is extremely sensitive and measuring ranges extend from 10 pg to 10 ng. Although the assay was free of contaminant interference when applied to avocado material, crude extract analysis yielded a composite of free and bound forms of ABA. Equivalents of 20 mg of plant material were spotted onto silica gel plates (GF245 solvent:toluene:ethyl acetate : acetic acid 25:15:3), developed and the relative Rf zones removed and subjected to RIA. The technique was tested on avocados

  9. Action of Abscisic Acid on Auxin Transport and its Relation to Phototropism

    Naqvi, S. M.; Engvild, Kjeld Christensen

    1974-01-01

    The action of abscisic acid on the kinetics of auxin transport through Zea mays L. (cv. Goudster) coleoptiles has been investigated. Abscisic acid applied simultaneously with indoleacetic acid-2-14C in the donor block reduced the transport intensity without materially affecting the basipetal...

  10. Amelioration of Chilling Injuries in Watermelon Seedlings by Abscisic Acid

    Korkmaz, Ahmet

    2002-01-01

    A greenhouse study, designed in a randomized complete block design with five replications, was carried out at Clemson University, Clemson, SC, USA, in the spring of 1997. The objective of the study was to investigate whether abscisic acid (ABA) would mitigate chilling damages in the watermelon, a chilling-sensitive plant. 'Crimson Sweet' [Citrullus lanatus (Thumb) Matsum. & Nakai.] watermelon seedlings were grown in a greenhouse with a temperature regime of 25ºC (day) and 20ºC...

  11. Radioimmunoassay for the determination of free and conjugated abscisic acid

    The characterization and application of a radioimmunoassay specific for free and conjugated abscisic acid (ABA) is reported, The antibodies produced against a bovine serum albumin-(+-)-ABA conjugate have a high affinity for ABA (Ka= 1.3 x 109 l mol-1). Trans, trans-ABA and related compounds, such as xanthoxin, phaseic acid, dihydrophaseic acid, vomifoliol or violaxanthin do not interfere with the assay. The detection limit of this method is 0.25 x 10-12 mol ABA, the measuring range extends to 20 x 10-12 mol, and average recoveries are 103%. Because of the high specificity of this immunoassay, no extract purification steps are required prior to analysis. Several hundred plants can be analyzed per day in a semi-automatic assay performance. ABA has been detected in all higher plant families examined, but was absent in the blue-green alga, Spirulina platensis, the liverwort Marchantia polymorpha, and two species of fungi. (orig.)

  12. Arabidopsis YAK1 regulates abscisic acid response and drought resistance.

    Kim, Dongjin; Ntui, Valentine Otang; Xiong, Liming

    2016-07-01

    Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. PMID:27264339

  13. Induction of phytic acid synthesis by abscisic acid in suspension-cultured cells of rice

    Matsuno, Koya; Fujimura, Tatsuhito

    2014-01-01

    A pathway of phytic acid (PA) synthesis in plants has been revealed via investigations of low phytic acid mutants. However, the regulation of this pathway is not well understood because it is difficult to control the environments of cells in the seeds, where PA is mainly synthesized. We modified a rice suspension culture system in order to study the regulation of PA synthesis. Rice cells cultured with abscisic acid (ABA) accumulate PA at higher levels than cells cultured without ABA, and PA a...

  14. Characterization and Functional Analysis of Pyrabactin Resistance-Like Abscisic Acid Receptor Family in Rice

    Tian, Xiaojie; Wang, Zhenyu; Li, Xiufeng; Lv, Tianxiao; Liu, Huazhao; Wang, Lizhi; Niu, Hongbin; Bu, Qingyun

    2015-01-01

    Background Abscisic acid (ABA) plays crucial roles in regulating plant growth and development, especially in responding to abiotic stress. The pyrabactin resistance-like (PYL) abscisic acid receptor family has been identified and widely characterized in Arabidopsis. However, PYL families in rice were largely unknown. In the present study, 10 out of 13 PYL orthologs in rice (OsPYL) were isolated and investigated. Results Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) an...

  15. Abscisic Acid and Abiotic Stress Tolerance in Crop Plants

    Sah, Saroj K.; Reddy, Kambham R.; Li, Jiaxu

    2016-01-01

    Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression. PMID:27200044

  16. Abscisic acid and pyrabactin improve vitamin C contents in raspberries.

    Miret, Javier A; Munné-Bosch, Sergi

    2016-07-15

    Abscisic acid (ABA) is a plant growth regulator with roles in senescence, fruit ripening and environmental stress responses. ABA and pyrabactin (a non-photosensitive ABA agonist) effects on red raspberry (Rubus idaeus L.) fruit development (including ripening) were studied, with a focus on vitamin and antioxidant composition. Application of ABA and/or pyrabactin just after fruit set did not affect the temporal pattern of fruit development and ripening; neither provitamin A (carotenoids) nor vitamin E contents were modified. In contrast, ABA and pyrabactin altered the vitamin C redox state at early stages of fruit development and more than doubled vitamin C contents at the end of fruit ripening. These were partially explained by changes in ascorbate oxidation and recycling. Therefore, ABA and pyrabactin applications may be used to increase vitamin C content of ripe fruits, increasing fruit quality and value. However, treatments containing pyrabactin-combined with ABA or alone-diminished protein content, thus partially limiting its potential applicability. PMID:26948608

  17. Compartmentation and equilibration of abscisic acid in isolated Xanthium cells

    Bray, E.A.; Zeevaart, J.A.D.

    1986-01-01

    The compartmentation of endogenous abscisic acid (ABA), applied (+/-)-(/sup 3/H)ABA, and (+/-)-trans-ABA was measured in isolated mesophyll cells of the Chicago strain of Xanthium strumarium L. The release of ABA to the medium in the presence or absence of DMSO was used to determine the equilibration of ABA in the cells. It was found that a greater percentage of the (+/-)-(/sup 3/H)ABA and the (+/-)-trans-ABA was released into the medium than of the endogenous ABA, indicating that applied ABA did not equilibrate with the endogenous material. Therefore, in further investigations only the compartmentation of endogenous ABA was studied. Endogenous ABA was released from Xanthium cells according to the pH gradients among the various cellular compartments. Thus, darkness, high external pH, KNO/sub 2/, and drought-stress all increased the efflux of ABA from the cells. Efflux of ABA from the cells in the presence of 0.6 M mannitol occurred within 30 seconds, but only 8% of the endogenous material was released during the 20 minute treatment.

  18. Plant water stress: Associations between ethylene and abscisic acid response

    Carolina Salazar

    2015-08-01

    Full Text Available Agriculture is severely impacted by water stress due either to excess (hypoxia/anoxia or deficit of water availability. Hypoxia/anoxia is associated with oxygen (O2 deficiency or depletion, inducing several anatomical, morphological, physiological, and molecular changes. The majority of these alterations are adaptive mechanisms to cope with low O2 availability; among them, alterations in shoot length, aerenchyma formation and adventitious roots have been described in several studies. The aim of this review was to address the association between abscisic acid (ABA and ethylene in function of water availability in plants. The major physiological responses to low O2 are associated with changes in root respiration, stomatal conductance, photosynthesis, and fermentation pathways in roots. In addition, several changes in gene expression have been associated with pathways that are not present under normal O2 supply. The expression of ethylene receptor genes is up-regulated by low O2, and ethylene seems to have a crucial role in anatomical and physiological effects during hypoxia/anoxia. During O2 depletion, ethylene accumulation down-regulates ABA by inhibiting rate-limiting enzymes in ABA biosynthesis and by activating ABA breakdown to phaseic acid. With regard to water deficit, drought is primarily sensed by the roots, inducing a signal cascade to the shoots via xylem causing physiological and morphological changes. Several genes are regulated up or down with osmotic stress; the majority of these responsive genes can be driven by either an ABA-dependent or ABA-independent pathway. Some studies suggest that ethylene shuts down leaf growth very fast after the plant senses limited water availability. Ethylene accumulation can antagonize the control of gas exchange and leaf growth upon drought and ABA accumulation.

  19. Effects of mechanical stress or abscisic acid on growth, water status and leaf abscisic acid content of eggplant seedlings

    Latimer, J. G.; Mitchell, C. A.

    1988-01-01

    Container-grown eggplant (Solanum melongena L. var esculentum Nees. 'Burpee's Black Beauty') seedlings were conditioned with brief, periodic mechanical stress or abscisic acid (ABA) in a greenhouse prior to outdoor exposure. Mechanical stress consisted of seismic (shaking) or thigmic (stem flexing) treatment. Exogenous ABA (10(-3) or 10(-4)M) was applied as a soil drench 3 days prior to outdoor transfer. During conditioning, only thigmic stress reduced stem elongation and only 10(-3) M ABA reduced relative growth rate (RGR). Both conditioning treatments increased leaf specific chlorophyll content, but mechanical stress did not affect leaf ABA content. Outdoor exposure of unconditioned eggplant seedlings decreased RGR and leaf-specific chlorophyll content, but tended to increase leaf ABA content relative to that of plants maintained in the greenhouse. Conditioning did not affect RGR of plants subsequently transferred outdoors, but did reduce stem growth. Seismic stress applied in the greenhouse reduced dry weight gain by plants subsequently transferred outdoors. Mechanical stress treatments increased leaf water potential by 18-25% relative to that of untreated plants.

  20. Study of endogenic abscisic acids and cytokinin content in soybean crops of variable salt sensitivity as well as the effect of exogenically applied abscisic acid on Cl/sup -/ translocation. [in German

    Roeb, G.

    1981-05-01

    A study of the phytohormones abscisic acid and cytokinin with respect to plant salt stress and its relationship to genetic control over endogen content. An analysis is made of the acid cytokinin content, and an investigation is made of the influence exerted by exogenic applied synthetic abscisic acid on Cl/sup -/ uptake and accumulation. 275 references, 14 figures, 11 tables.

  1. In vitro reconstitution of an abscisic acid signalling pathway

    Fujii, Hiroaki

    2009-11-18

    The phytohormone abscisic acid (ABA) regulates the expression of many genes in plants; it has critical functions in stress resistance and in growth and development. Several proteins have been reported to function as ABA receptors, and many more are known to be involved in ABA signalling. However, the identities of ABA receptors remain controversial and the mechanism of signalling from perception to downstream gene expression is unclear. Here we show that by combining the recently identified ABA receptor PYR1 with the type 2C protein phosphatase (PP2C) ABI1, the serine/threonine protein kinase SnRK2.6/OST1 and the transcription factor ABF2/AREB1, we can reconstitute ABA-triggered phosphorylation of the transcription factor in vitro. Introduction of these four components into plant protoplasts results in ABA-responsive gene expression. Protoplast and test-tube reconstitution assays were used to test the function of various members of the receptor, protein phosphatase and kinase families. Our results suggest that the default state of the SnRK2 kinases is an autophosphorylated, active state and that the SnRK2 kinases are kept inactive by the PP2Cs through physical interaction and dephosphorylation. We found that in the presence of ABA, the PYR/PYL (pyrabactin resistance 1/PYR1-like) receptor proteins can disrupt the interaction between the SnRK2s and PP2Cs, thus preventing the PP2C-mediated dephosphorylation of the SnRK2s and resulting in the activation of the SnRK2 kinases. Our results reveal new insights into ABA signalling mechanisms and define a minimal set of core components of a complete major ABA signalling pathway. © 2009 Macmillan Publishers Limited. All rights reserved.

  2. Transcriptional Responses to Gibberellin and Abscisic Acid in Barley Aleurone

    Kegui Chen; Yong-Qiang Charles An

    2006-01-01

    Cereal aleurone has been established as a model system to investigate giberrellin (GA) and abscisic acid (ABA) responses. Using Barley 1 GeneChip, we examined the mRNA accumulation of over 22 000 genes in de-embryonated barley aleurone treated with GA and ABA. We observed that 1328 genes had more than a threefold change in response to GA treatment, whereas 206 genes had a more than threefold change in response to ABA treatment. Interestingly, approximately 2.5-fold more genes were up-regulated than downregulated by ABA. Eighty-three genes were differentially regulated by both GA and ABA. Most of the genes were subject to antagonistic regulation by ABA and GA, particularly for genes related to seed maturation and germination, such as genes encoding late embryogenesis abundant proteins and storage mobilization enzymes. This supports the antagonistic roles of GA and ABA in seed maturation and seed germination.Interestingly, we observed that a significant percentage of the genes were coordinately regulated by both GA and ABA. Some GA-responsive genes encoded proteins involved in ethylene, jasmonate, brassinosteroid and auxin metabolic and signaling transduction pathways, suggesting their potential interaction with the GA response. We also identified a group of transcription factor genes, such as MYB and Homeobox genes, that were differentially regulated by GA. In addition, a number of GA- and/or ABA-responsive genes encoded components potentially involved in GA and ABA signal transduction pathway. Overall, the present study provides a comprehensive and global view of transcript expression accompanying the GA and ABA response in barley aleurone and identifies a group of genes with potential regulatory functions in GA- and ABA-signaling pathways for future functional validation.

  3. Abscisic acid ameliorates the systemic sclerosis fibroblast phenotype in vitro

    Bruzzone, Santina, E-mail: santina.bruzzone@unige.it [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Advanced Biotechnology Center, Largo Rosanna Benzi 10, 16132 Genova (Italy); Battaglia, Florinda [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Mannino, Elena [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Parodi, Alessia [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Fruscione, Floriana [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Advanced Biotechnology Center, Largo Rosanna Benzi 10, 16132 Genova (Italy); Basile, Giovanna [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Salis, Annalisa; Sturla, Laura [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Negrini, Simone; Kalli, Francesca; Stringara, Silvia [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Filaci, Gilberto [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Department of Internal Medicine, Viale Benedetto XV 6, 16132 Genova (Italy); and others

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer ABA is an endogenous hormone in humans, regulating different cell responses. Black-Right-Pointing-Pointer ABA reverts some of the functions altered in SSc fibroblasts to a normal phenotype. Black-Right-Pointing-Pointer UV-B irradiation increases ABA content in SSc cultures. Black-Right-Pointing-Pointer SSc fibroblasts could benefit from exposure to ABA and/or to UV-B. -- Abstract: The phytohormone abscisic acid (ABA) has been recently identified as an endogenous hormone in humans, regulating different cell functions, including inflammatory processes, insulin release and glucose uptake. Systemic sclerosis (SSc) is a chronic inflammatory disease resulting in fibrosis of skin and internal organs. In this study, we investigated the effect of exogenous ABA on fibroblasts obtained from healthy subjects and from SSc patients. Migration of control fibroblasts induced by ABA was comparable to that induced by transforming growth factor-{beta} (TGF-{beta}). Conversely, migration toward ABA, but not toward TGF-{beta}, was impaired in SSc fibroblasts. In addition, ABA increased cell proliferation in fibroblasts from SSc patients, but not from healthy subjects. Most importantly, presence of ABA significantly decreased collagen deposition by SSc fibroblasts, at the same time increasing matrix metalloproteinase-1 activity and decreasing the expression level of tissue inhibitor of metalloproteinase (TIMP-1). Thus, exogenously added ABA appeared to revert some of the functions altered in SSc fibroblasts to a normal phenotype. Interestingly, ABA levels in plasma from SSc patients were found to be significantly lower than in healthy subjects. UV-B irradiation induced an almost 3-fold increase in ABA content in SSc cultures. Altogether, these results suggest that the fibrotic skin lesions in SSc patients could benefit from exposure to high(er) ABA levels.

  4. Abscisic acid ameliorates the systemic sclerosis fibroblast phenotype in vitro

    Highlights: ► ABA is an endogenous hormone in humans, regulating different cell responses. ► ABA reverts some of the functions altered in SSc fibroblasts to a normal phenotype. ► UV-B irradiation increases ABA content in SSc cultures. ► SSc fibroblasts could benefit from exposure to ABA and/or to UV-B. -- Abstract: The phytohormone abscisic acid (ABA) has been recently identified as an endogenous hormone in humans, regulating different cell functions, including inflammatory processes, insulin release and glucose uptake. Systemic sclerosis (SSc) is a chronic inflammatory disease resulting in fibrosis of skin and internal organs. In this study, we investigated the effect of exogenous ABA on fibroblasts obtained from healthy subjects and from SSc patients. Migration of control fibroblasts induced by ABA was comparable to that induced by transforming growth factor-β (TGF-β). Conversely, migration toward ABA, but not toward TGF-β, was impaired in SSc fibroblasts. In addition, ABA increased cell proliferation in fibroblasts from SSc patients, but not from healthy subjects. Most importantly, presence of ABA significantly decreased collagen deposition by SSc fibroblasts, at the same time increasing matrix metalloproteinase-1 activity and decreasing the expression level of tissue inhibitor of metalloproteinase (TIMP-1). Thus, exogenously added ABA appeared to revert some of the functions altered in SSc fibroblasts to a normal phenotype. Interestingly, ABA levels in plasma from SSc patients were found to be significantly lower than in healthy subjects. UV-B irradiation induced an almost 3-fold increase in ABA content in SSc cultures. Altogether, these results suggest that the fibrotic skin lesions in SSc patients could benefit from exposure to high(er) ABA levels.

  5. Analysis of the plant hormones Abscisic acid and Xanthoxin in trees of the two stands No. 79 and 109 in the Hils

    Majcherczyk, A.; Huettermann, A.

    1984-01-01

    Pilca abies of two different treations were compared. The phytohormones Abscisic acid and Xanthoxin were analysed. The role and the content of abscisic acid and Xanthoxin in trees under stress induced by acid rain were investigated.

  6. Abscisic acid biosynthesis in leaves and roots of Xanthium strumarium

    Creelman, R.A.; Gage, D.A.; Stults, J.T.; Zeevaart, J.A.D.

    1987-11-01

    Research on the biosynthesis of abscisic acid (ABA) has focused primarily on two pathways: (a) the direct pathway from farnesyl pyrophosphate, and (b) the indirect pathway involving a carotenoid precursor. The authors have investigated which biosynthetic pathway is operating in turgid and stressed Xanthium leaves, and in stressed Xanthium roots using long-term incubations in /sup 18/O/sub 2/. It was found that in stressed leaves three atoms of /sup 18/O from /sup 18/O/sub 2/ are incorporated into the ABA molecule, and that the amount of /sup 18/O incorporated increases with time. One /sup 18/O atom is incorporated rapidly into the carboxyl group of ABA, whereas the other two atoms are very slowly incorporated into the ring oxygens. The fourth oxygen atom in the carboxyl group of ABA is derived from water. ABA from stressed roots of Xanthium incubated in /sup 18/O/sub 2/ shows a labeling pattern similar to that of ABA in stressed leaves, but with incorporation of more /sup 18/O into the tertiary hydroxyl group at C-1' after 6 and 12 hours than found in ABA from stressed leaves. It is proposed that the precursors to stress-induced ABA are xanthophylls, and that a xanthophyll lacking an oxygen function at C-6 plays a crucial role in ABA biosynthesis in Xanthium roots. In turgid Xanthium leaves, /sup 18/O is incorporated into ABA to a much lesser extent that it is in stressed leaves, whereas exogenously applied /sup 14/C-ABA is completely catabolized within 48 hours. This suggests that ABA in turgid leaves is either (a) made via a biosynthetic pathway which is different from the one in stressed leaves, or (b) has a half-life on the order of days as compared with a half-life of 15.5 hours in water-stressed Xanthium leaves. Phaseic acid showed a labeling pattern similar to that of ABA, but with an additional /sup 18/O incorporated during 8'-hydroxylation of ABA to phaseic acid.

  7. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth

    Castellarin, Simone D.; Gambetta, Gregory A.; Wada, Hiroshi; Krasnow, Mark N.; Cramer, Grant R.; Peterlunger, Enrico; Shackel, Kenneth A.; Matthews, Mark A.

    2015-01-01

    Highlight The earliest events in ripening are decreases in turgor, softening, and increases in abscisic acid. Later events integral to regulating colour development include growth, further increases in abscisic acid, and sugar accumulation.

  8. Plant Responses to Water Stress as Affected by Abscisic Acid and Benzyladenine

    Pospíšilová, Jana; Haisel, Daniel; Schnablová, Renáta; Synková, Helena; Baťková, Petra

    Montreal : International Society of Photosynthesis , 2005 - (Van der Est, A.; Bruce, D.), s. 593-595 R&D Projects: GA ČR GA522/02/1099 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * benzyladenine * chlorophyl content Subject RIV: ED - Physiology

  9. Interactions between abscisic acid and cytokinins during water stress and subsequent rehydration

    Pospíšilová, Jana; Vágner, Martin; Malbeck, Jiří; Trávníčková, Alena; Baťková, Petra

    2005-01-01

    Roč. 49, - (2005), s. 533-540. ISSN 0006-3134 R&D Projects: GA ČR GA522/02/1099; GA AV ČR(CZ) IAA638105 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * cytokinins * water stress Subject RIV: EF - Botanics Impact factor: 0.792, year: 2005

  10. Diurnal variation of cytokinin, auxin and abscisic acid levels in tobacco leaves

    Nováková, Marie; Motyka, Václav; Dobrev, Petre; Malbeck, Jiří; Gaudinová, Alena

    2005-01-01

    Roč. 56, č. 421 (2005), s. 2877-2883. ISSN 0022-0957 R&D Projects: GA ČR GA206/03/0369; GA MŠk LN00A081 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * auxin * cytokinin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.336, year: 2005

  11. Endogenous cytokinins, auxins, and abscisic acid in red algae from Brazil

    Yokoya, N. S.; Stirk, W. A.; van Staden, J.; Novák, Ondřej; Turečková, Veronika; Pěnčík, Aleš; Strnad, Miroslav

    2010-01-01

    Roč. 46, č. 6 (2010), s. 1198-1205. ISSN 0022-3646 R&D Projects: GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : ENDOGENOUS * CYTOKININS * AUXINS * ABSCISIC ACID * RED * ALGAE * BRAZIL Subject RIV: EF - Botanics Impact factor: 2.239, year: 2010

  12. Effects of high night temperature and abscisic acid (ABA) on rice (Oryza sativa L.) physiology

    High night temperature (HNT) is known to decrease rice yields. The impact of abscisic acid (ABA) on plants has been the subject of many studies. However, little or no work has been carried out on rice response to ABA under HNT-stress conditions. This study determined the effects of ABA on rice leaf ...

  13. Crucial Roles of Abscisic Acid Biogenesis in Virulence of Rice Blast Fungus Magnaporthe oryzae

    Spence, Carla A.; Lakshmanan, Venkatachalam; Donofrio, Nicole; Bais, Harsh P.

    2015-01-01

    Rice suffers dramatic yield losses due to blast pathogen Magnaporthe oryzae. Pseudomonas chlororaphis EA105, a bacterium that was isolated from the rice rhizosphere, inhibits M. oryzae. It was shown previously that pre-treatment of rice with EA105 reduced the size of blast lesions through jasmonic acid (JA)- and ethylene (ETH)-mediated ISR. Abscisic acid (ABA) acts antagonistically toward salicylic acid (SA), JA, and ETH signaling, to impede plant defense responses. EA105 may be reducing the ...

  14. Effects of Abscisic Acid, Gibberellin, Ethylene and Their Interactions on Production of Phenolic Acids in Salvia miltiorrhiza Bunge Hairy Roots

    Liang, Zongsuo; Ma, Yini; Xu, Tao; Cui, Beimi; Liu, Yan; Guo, Zhixin; Yang, Dongfeng

    2013-01-01

    Salvia miltiorrhiza is one of the most important traditional Chinese medicinal plants because of its excellent performance in treating coronary heart disease. Phenolic acids mainly including caffeic acid, rosmarinic acid and salvianolic acid B are a group of active ingredients in S. miltiorrhiza. Abscisic acid (ABA), gibberellin (GA) and ethylene are three important phytohormones. In this study, effects of the three phytohormones and their interactions on phenolic production in S. miltiorrhiz...

  15. Quantification of Abscisic Acid, Cytokinin, and Auxin Content in Salt-Stressed Plant Tissues

    Dobrev, P.; Vaňková, R. (Radomíra)

    2012-01-01

    Plant hormones cytokinins, auxin (indole-3-acetic acid), and abscisic acid are central to regulation of plant growth and defence to abiotic stresses such as salinity. Quantification of the hormone levels and determination of their ratios can reveal different plant strategies to cope with the stress, e.g., suppression of growth or mobilization of plant metabolism. This chapter describes a procedure enabling such quantification. Due to the high variability of these hormones in plant tissues, it...

  16. Response of cytokinin pool and cytokinin oxidase/dehydrogenase activity to abscisic acid exhibits organ specificity in peas

    Vaseva, I.; Todorova, D.; Malbeck, Jiří; Trávníčková, Alena; Macháčková, Ivana

    2008-01-01

    Roč. 30, č. 2 (2008), s. 151-155. ISSN 0137-5881 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid * Cytokinins * Cytokinin Subject RIV: EF - Botanics Impact factor: 0.807, year: 2008

  17. Starch and sucrose synthesis in Phaseolus vulgaris as affected by light, CO2, and abscisic acid

    Phaseolus vulgaris L. leaves were subjected to various light, CO2, and O2 levels and abscisic acid, then given a 10 minute pulse of 14CO2 followed by a 5 minute chase with unlabeled CO2. After the chase period, very little label remained in the ionic fractions except at low CO2 partial pressure. Most label was found in the neutral, alcohol soluble fraction or in the insoluble fraction digestable by amyloglucosidase. Sucrose formation was linearly related to assimilation rate. Starch formation increased linearly with assimilation rate, but did not occur if the assimilation rate was below 4 micromoles per square meter per second. Neither abscisic acid, nor high CO2 in combination with low O2 caused significant perturbations of the sucrose/starch formation ratio. These studies indicate that the pathways for starch and sucrose synthesis both are controlled by the rate of net CO2 assimilation, with sucrose the preferred product at very low assimilation rates

  18. Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape

    Gambetta, Gregory A.; Matthews, Mark A.; Shaghasi, Tarana H.; McElrone, Andrew J.; Castellarin, Simone D.

    2010-01-01

    The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing...

  19. Abscisic acid, gibberellins and brassinosteroids in Kelpak (R), a commercial seaweed extract made from Ecklonia maxima

    Stirk, W. A.; Tarkowská, Danuše; Turečková, Veronika; Strnad, Miroslav; van Staden, J.

    2014-01-01

    Roč. 26, č. 1 (2014), s. 561-567. ISSN 0921-8971 R&D Projects: GA MŠk LK21306; GA ČR GA206/09/1284; GA MŠk(CZ) LO1204 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Abscisic acid * Agricultural biostimulant * Brassinosteroids Subject RIV: EF - Botanics Impact factor: 2.559, year: 2014

  20. Abscisic acid is not necessary for gravitropism in primary roots of Zea mays

    Moore, R.

    1990-01-01

    Primary roots of Zea mays L. cv. Tx 5855 treated with fluridone are strongly graviresponsive, but have undetectable levels of abscisic acid (ABA). Primary roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays are also graviresponsive despite having undetectable amounts of ABA. Graviresponsive roots of untreated and wild-type seedlings contain 286 to 317 ng ABA g-1 f. wt, respectively. These results indicate that ABA is not necessary for root gravicurvature.

  1. Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions

    Yongjie Meng; Feng Chen; Haiwei Shuai; Xiaofeng Luo; Jun Ding; Shengwen Tang; Shuanshuan Xu; Jianwei Liu; Weiguo Liu; Junbo Du; Jiang Liu; Feng Yang; Xin Sun; Taiwen Yong; Xiaochun Wang

    2016-01-01

    Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interest...

  2. Exogenous abscisic acid significantly affects proteome in tea plant (Camellia sinensis) exposed to drought stress

    Lin Zhou; Hui Xu; Sue Mischke; Meinhardt, Lyndel W.; Dapeng Zhang; Xujun Zhu; Xinghui Li; Wanping Fang

    2014-01-01

    Tea [Camellia sinensis (L.) O. Kuntze] is an important economic crop, and drought is the most important abiotic stress affecting yield and quality. Abscisic acid (ABA) is an important phytohormone responsible for activating drought resistance. Increased understanding of ABA effects on tea plant under drought stress is essential to develop drought-tolerant tea genotypes, along with crop management practices that can mitigate drought stress. The objective of the present investigation is evaluat...

  3. EFFECT OF EXOGENOUS ABSCISIC ACID ON GROWTH AND BIOCHEMICAL CHANGES IN THE HALOPHYTE SUAEDA MARITIMA

    Anbarasi G.

    2015-04-01

    Full Text Available Different types of phytohormones are being extensively used to alleviate the adverse effect of salinity stress on plant growth. Among those, Abscisic acid (ABA is a plant stress hormone and one of the most important signaling molecules in plants. Drought and salinity activate De-novo abscisic acid synthesis prevent further water loss by evaporation through stomata, mediated by changes in the guard cell turgor pressure. Under osmotic stress abscisic acid induce the accumulation of protein involved in the biosynthesis of osmolites which increasing the stress tolerance of plant. In addition, exogenous application of ABA enhances the tolerance of plants or plant cells to cold, heat, drought, anoxia and heavy metal stresses. This study was carried out to study the exogenous abscisic (ABA acid induced regulatory role on the growth, water content, protein content, chlorophyll content, osmolyte accumulation and protein profiling through SDS PAGE in a halophyte, Suaeda maritima. The osmolyte accumulation of proline and glycine betaine was found to be more in 50 µM ABA concentrations. The protein profiling through SDS PAGE revealed that ̴ 66KDa proteins was not expressed in the control plant and in 10μM ABA treated plants. Interestingly, the ABA treatment induced a new protein of 14.2KDa in 10μM concentration. The ABA treated plants with concentrations 50μM, 100μM and 150μM showed changes in the expression of protein in abundance than the control and 10μM ABA treated plants. The findings in this study indicate that among all the concentrations, 50μM ABA concentration treated plants exhibited higher growth rate.

  4. Immunoaffinity chromatography of abscisic acid combined with electrospray liquid chromatography–mass spectrometry

    Hradecká, Veronika; Novák, Ondřej; Havlíček, Libor; Strnad, Miroslav

    2007-01-01

    Roč. 847, č. 2 (2007), s. 162-173. ISSN 1570-0232 R&D Projects: GA MŠk(CZ) LC06034; GA AV ČR IBS5038351 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : abscisic acid * immunoaffinity chromatography * liquid chromatography-mass spectrometry Subject RIV: ED - Physiology Impact factor: 2.935, year: 2007

  5. Quantification of Abscisic Acid, Cytokinin, and Auxin Content in Salt-Stressed Plant Tissues

    Dobrev, Petre; Vaňková, Radomíra

    Vol. 913. New York: Humana Press, 2012 - (Shabala, S.; Cuin, T.), s. 251-261. (Methods in Molecular Biology). ISBN 978-1-61779-985-3 R&D Projects: GA MŠk(CZ) LD11073 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid * Auxin * Cytokinin Subject RIV: ED - Physiology http://home.ueb.cas.cz/publikace/2012_Dobrev.pdf

  6. Effect of drought and abscisic acid application on the osmotic adjustment of four wheat cultivars

    The accumulation of osmolytes in leaf tissues and the abscisic acid-induced stomatal closure are well-recognized mechanisms associated with drought tolerance in crop plants. We determine the response in terms of osmotic potential and the contents of leaf proline, glycine betaine and soluble sugar at booting and grain filling stages of four wheat (Triticum aestivum L.) cultivars to drought and exogenously applied abscisic acid (ABA) in a pot study. Leaf sample were collected 3, 6 and 9 days after drought induction and at 48 and 72 h of re-watering (recovery). Marked decreases in osmotic potential associated with the accumulation of proline, glycine betaine and soluble sugars occurred under conditions of drought stress Accession 011320 was most sensitive to drought and showed the largest decrease in osmotic potential and least accumulation of proline, sugar and glycine betaine The inhibitory effects of drought stress were ameliorated by exogenous application of ABA. This ameliorating effect was more pronounced at the booting than at grain filling stage particularly in the sensitive accession 011320. Upon rewatering the recovery from drought stress was found to be greater in case of abscisic acid application. The leaf praline content is seen to be a suitable indicator for selecting drought-tolerant genotypes. (author)

  7. Exogenous Abscisic Acid and Gibberellic Acid Elicit Opposing Effects on Fusarium graminearum Infection in Wheat.

    Buhrow, Leann M; Cram, Dustin; Tulpan, Dan; Foroud, Nora A; Loewen, Michele C

    2016-09-01

    Although the roles of salicylate (SA) and jasmonic acid (JA) have been well-characterized in Fusarium head blight (FHB)-infected cereals, the roles of other phytohormones remain more ambiguous. Here, the association between an array of phytohormones and FHB pathogenesis in wheat is investigated. Comprehensive profiling of endogenous hormones demonstrated altered cytokinin, gibberellic acid (GA), and JA metabolism in a FHB-resistant cultivar, whereas challenge by Fusarium graminearum increased abscisic acid (ABA), JA, and SA in both FHB-susceptible and -resistant cultivars. Subsequent investigation of ABA or GA coapplication with fungal challenge increased and decreased FHB spread, respectively. These phytohormones-induced effects may be attributed to alteration of the F. graminearum transcriptome because ABA promoted expression of early-infection genes, including hydrolases and cytoskeletal reorganization genes, while GA suppressed nitrogen metabolic gene expression. Neither ABA nor GA elicited significant effects on F. graminearum fungal growth or sporulation in axenic conditions, nor do these phytohormones affect trichothecene gene expression, deoxynivalenol mycotoxin accumulation, or SA/JA biosynthesis in F. graminearum-challenged wheat spikes. Finally, the combined application of GA and paclobutrazol, a Fusarium fungicide, provided additive effects on reducing FHB severity, highlighting the potential for combining fungicidal agents with select phytohormone-related treatments for management of FHB infection in wheat. PMID:27135677

  8. Ascorbic acid and reactive oxygen species are involved in the inhibition of seed germination by abscisic acid in rice seeds

    Ye, Nenghui; Zhu, Guohui; Liu, Yinggao; Zhang, Aying; Li, Yingxuan; Liu, Rui; Shi, Lu; Jia, Liguo; Zhang, Jianhua

    2011-01-01

    The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination, but the mechanism of antagonism during this process is not known. The possible links among ABA, reactive oxygen species (ROS), ascorbic acid (ASC), and GA during rice seed germination were investigated. Unlike in non-seed tissues where ROS production is increased by ABA, ABA reduced ROS production in imbibed rice seeds, especially in the embryo region. Such reduced ROS also led to...

  9. Antagonism between abscisic acid and gibberellins is partially mediated by ascorbic acid during seed germination in rice

    Ye, Nenghui; Zhang, Jianhua

    2012-01-01

    The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination,1,2 but the mechanism of antagonism during this process is not known. In the associated study,3 we investigated the relationship among ABA, reactive oxygen species (ROS), ascorbic acid (ASC) and GA during rice seed germination. ROS production is reduced by ABA, which hence results in decreasing ASC accumulation during imbibition. GA accumulation was also suppressed by a reduced ROS...

  10. Salicylic acid antagonizes abscisic acid inhibition of shoot growth and cell cycle progression in rice

    Meguro, Ayano; Sato, Yutaka

    2014-04-01

    We analysed effects of abscisic acid (ABA, a negative regulatory hormone), alone and in combination with positive or neutral hormones, including salicylic acid (SA), on rice growth and expression of cell cycle-related genes. ABA significantly inhibited shoot growth and induced expression of OsKRP4, OsKRP5, and OsKRP6. A yeast two-hybrid assay showed that OsKRP4, OsKRP5, and OsKRP6 interacted with OsCDKA;1 and/or OsCDKA;2. When SA was simultaneously supplied with ABA, the antagonistic effect of SA completely blocked ABA inhibition. SA also blocked ABA inhibition of DNA replication and thymidine incorporation in the shoot apical meristem. These results suggest that ABA arrests cell cycle progression by inducing expression of OsKRP4, OsKRP5, and OsKRP6, which inhibit the G1/S transition, and that SA antagonizes ABA by blocking expression of OsKRP genes.

  11. Nitric oxide functions in both methyl jasmonate signaling and abscisic acid signaling in Arabidopsis guard cells

    Saito, Naoki; Nakamura, Yoshimasa; Mori, Izumi C.; Murata, Yoshiyuki

    2009-01-01

    Intracellular components in methyl jasmonate (MeJA) signaling remain largely unknown, to compare those in well-understood abscisic acid (ABA) signaling. We have reported that nitric oxide (NO) is a signaling component in MeJA-induced stomatal closure, as well as ABA-induced stomatal closure in the previous study. To gain further information about the role of NO in the guard cell signaling, NO production was examined in an ABA- and MeJA-insensitive Arabidopsis mutant, rcn1. Neither MeJA nor AB...

  12. ATAF1 transcription factor directly regulates abscisic acid biosynthetic gene NCED3 in Arabidopsis thaliana

    Jensen, Michael Krogh; Lindemose, Søren; De Masi, Federico;

    2013-01-01

    ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin-immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT...... key abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP-qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis....

  13. Possible role for abscisic acid in regulation of photosynthetic and photorespiratory carbon metabolism in barley leaves

    The influence of abscisic acid (ABA) on carbon metabolism, rate of photorespiration, and the activity of the photorespiratory enzymes ribulose bisphosphate oxygenase and glycolate oxidase in 7-day-old barley seedlings (Hordeum vulgare L. var. Alfa) was investigated. Plants treated with ABA had enhanced incorporation of labeled carbon from 14CO2 into glycolic acid, glycine, and serine, while 14C incorporation into 3-phosphoglyceric acid and sugarphosphate esters was depressed. Parallel with this effect, treated plants showed a rise in activity of RuBP oxygenase and glycolic acid oxidase. The rate of photorespiration was increased twofold by ABA treatment at IO-6 molar while the CO2-compensation point increased 46% and stomatal resistance increased more than twofold over control plants

  14. Abscisic acid-cytokinin antagonism modulates resistance against pseudomonas syringae in Tobacco

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2014-01-01

    Phytohormones are known as essential regulators of plant defenses, with ethylene, jasmonic acid, and salicylic acid as the central immunity backbone, while other phytohormones have been demonstrated to interact with this. Only recently, a function of the classic phytohormone cytokinin in plant...... immunity has been described in Arabidopsis, rice, and tobacco. Although interactions of cytokinins with salicylic acid and auxin have been indicated, the complete network of cytokinin interactions with other immunity-relevant phytohormones is not yet understood. Therefore, we studied the interaction...... of kinetin and abscisic acid as a negative regulator of plant immunity to modulate resistance in tobacco against Pseudomonas syringae. By analyzing infection symptoms, pathogen proliferation, and accumulation of the phytoalexin scopoletin as a key mediator of kinetin-induced resistance in tobacco...

  15. Ammonium regulates embryogenic potential in Cucurbita pepo through pH-mediated changes in endogenous auxin and abscisic acid

    Pěnčík, Aleš; Turečková, Veronika; Paulisić, S.; Rolčík, Jakub; Strnad, Miroslav; Mihaljević, S.

    2015-01-01

    Roč. 122, č. 1 (2015), s. 89-100. ISSN 0167-6857 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Abscisic acid * Ammonium * Indole-3-acetic acid Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.125, year: 2014

  16. Abscisic acid content and stomatal sensitivity to CO/sub 2/ in leaves of Xanthium strumarium L. after pretreatments in warm and cold growth chambers

    Raschke, K.; Pierce, M.; Popiela, C.C.

    1976-01-01

    The degree of stomatal sensitivity to CO/sub 2/ was positively correlated with the content of abscisic acid of leaves of Xanthium strumarium grown in a greenhouse and then transferred for 24 hours or more to a cold (5/10 C, night/day) or a warm growth chamber (20/23 C). This correlation did not exist in plants kept in the greenhouse continuously (high abscisic acid, no CO/sub 2/ sensitivity), nor in plants transferred from the cold to the warm chamber (low absicisic acid, high CO/sub 2/ sensitivity). The abscisic acid content of leaves was correlated with water content only within narrow limits, if at all. At equal water contents, prechilled leaves contained more abscisic acid than leaves of plants pretreated in the warm chamber. There appear to be at least two compartments for abscisic acid in the leaf.

  17. Large-scale proteome analysis of abscisic acid and ABSCISIC ACID INSENSITIVE3-dependent proteins related to desiccation tolerance in Physcomitrella patens.

    Yotsui, Izumi; Serada, Satoshi; Naka, Tetsuji; Saruhashi, Masashi; Taji, Teruaki; Hayashi, Takahisa; Quatrano, Ralph S; Sakata, Yoichi

    2016-03-18

    Desiccation tolerance is an ancestral feature of land plants and is still retained in non-vascular plants such as bryophytes and some vascular plants. However, except for seeds and spores, this trait is absent in vegetative tissues of vascular plants. Although many studies have focused on understanding the molecular basis underlying desiccation tolerance using transcriptome and proteome approaches, the critical molecular differences between desiccation tolerant plants and non-desiccation plants are still not clear. The moss Physcomitrella patens cannot survive rapid desiccation under laboratory conditions, but if cells of the protonemata are treated by the phytohormone abscisic acid (ABA) prior to desiccation, it can survive 24 h exposure to desiccation and regrow after rehydration. The desiccation tolerance induced by ABA (AiDT) is specific to this hormone, but also depends on a plant transcription factor ABSCISIC ACID INSENSITIVE3 (ABI3). Here we report the comparative proteomic analysis of AiDT between wild type and ABI3 deleted mutant (Δabi3) of P. patens using iTRAQ (Isobaric Tags for Relative and Absolute Quantification). From a total of 1980 unique proteins that we identified, only 16 proteins are significantly altered in Δabi3 compared to wild type after desiccation following ABA treatment. Among this group, three of the four proteins that were severely affected in Δabi3 tissue were Arabidopsis orthologous genes, which were expressed in maturing seeds under the regulation of ABI3. These included a Group 1 late embryogenesis abundant (LEA) protein, a short-chain dehydrogenase, and a desiccation-related protein. Our results suggest that at least three of these proteins expressed in desiccation tolerant cells of both Arabidopsis and the moss are very likely to play important roles in acquisition of desiccation tolerance in land plants. Furthermore, our results suggest that the regulatory machinery of ABA- and ABI3-mediated gene expression for desiccation

  18. Effect of abscisic acid, Paclobutrazol and Salicylic acid on the growth and Pigment variation in Solanum Trilobatum (l

    D. Nivedithadevi

    2012-09-01

    Full Text Available Solanum trilobatum (Family: Solanaceae is one of the common Indian medicinal plants and it has been used in traditional medicine for many centuries. This plant is a thorny creeper with bluish violet flower, more commonly available in southern India has been used traditional in Siddha system of medicines to treat various diseases. The roots, leaves, berries and flowers are used for cough. The decoction of entire Solanum trilobatum plant is used to treat acute and chronic bronchitis. It has been widely used to treat respiratory disorders. This plant is commonly used to treat asthma, cough, dysonoea, chronic febrile infections and difficult parturition. The constituents of this plant include sobatum, -solamarine, solanine, solasodine, glycoalkaloid, diosogenin and tomatidine. Plant growth regulators are substance that influences physiological processes of plants at very low concentration. Abscisic acid is a many important plant growth development processed. Paclobutrazol is a triazolic group of fungicide which has plant growth regulating properties. Salicylic acid is phenolic phytohormones and is formed in plants with role of plant growth and development. The given treatments were started at 70th day followed by 80th, 90th and 100th days. The groups were treated with respect growth hormones by spraying method. After 10th day, the plants were harvested for further analysis. On over all physical assessment plants treated with paclobutrazol were found to have more whole plant fresh weight, dry weight, root length and stem length followed by abscisic acid and salicylic acid. After the physical evaluation, the leaves were collected from each group for pigment analysis. Chlorophyll, carotenoid, anthocyanin and xanthophylls pigment contents were increased in abscisic acid followed by paclobutrazol and salicylic acid.

  19. Abscisic acid as a factor in regulation of photosynthetic carbon metabolism of pea seedlings

    Maria Faltynowicz

    2014-02-01

    Full Text Available The influence of abscisic acid (ABA on carbon metabolism and the activity of ribulosebisphosphate (RuBP and phosphoenolpyruvate (PEP carboxylases in 8-day-old pea seedlings was investigated. It was endeavoured to correlate the changes observed in metabolic processes with the endogenous ABA level. In plants treated with ABA incorporation of labeled carbon into sucrose, glucose, fructose and sugar phosphates was depressed, while 14C incorporation into starch, ribulose and malic acid was enhanced. The activity of RuBP carboxylase was considerably lowered, whereas that of PEP carboxylase was slightly increased. It is considered that inhibition of photosynthesis due to the action of ABA is caused to a great extent by the obstruction of the C-3 pathway and reduced activity of RuBP carboxylase, whereas (β-carboxylation was not blocked.

  20. The antagonistic regulation of abscisic acid-inhibited root growth by brassinosteroids is partially mediated via direct suppression of ABSCISIC ACID INSENSITIVE 5 expression by BRASSINAZOLE RESISTANT 1.

    Yang, Xiaorui; Bai, Yang; Shang, Jianxiu; Xin, Ruijiao; Tang, Wenqiang

    2016-09-01

    Brassinosteroids (BRs) and abscisic acid (ABA) are plant hormones that antagonistically regulate many aspects of plant growth and development; however, the mechanisms that regulate the crosstalk of these two hormones are still not well understood. BRs regulate plant growth and development by activating BRASSINAZOLE RESISTANT 1 (BZR1) family transcription factors. Here we show that the crosstalk between BRs and ABA signalling is partially mediated by BZR1 regulated gene expression. bzr1-1D is a dominant mutant with enhanced BR signalling; our results showed that bzr1-1D mutant is less sensitive to ABA-inhibited primary root growth. By RNA sequencing, a subset of BZR1 regulated ABA-responsive root genes were identified. Of these genes, the expression of a major ABA signalling component ABA INSENSITIVE 5 (ABI5) was found to be suppressed by BR and by BZR1. Additional evidences showed that BZR1 could bind strongly with several G-box cis-elements in the promoter of ABI5, suppress the expression of ABI5 and make plants less sensitive to ABA. Our study demonstrated that ABI5 is a direct target gene of BZR1, and modulating the expression of ABI5 by BZR1 plays important roles in regulating the crosstalk between the BR and ABA signalling pathways. PMID:27149247

  1. Functional annotation of the transcriptome of Sorghum bicolor in response to osmotic stress and abscisic acid

    Kumari Sunita

    2011-10-01

    Full Text Available Abstract Background Higher plants exhibit remarkable phenotypic plasticity allowing them to adapt to an extensive range of environmental conditions. Sorghum is a cereal crop that exhibits exceptional tolerance to adverse conditions, in particular, water-limiting environments. This study utilized next generation sequencing (NGS technology to examine the transcriptome of sorghum plants challenged with osmotic stress and exogenous abscisic acid (ABA in order to elucidate genes and gene networks that contribute to sorghum's tolerance to water-limiting environments with a long-term aim of developing strategies to improve plant productivity under drought. Results RNA-Seq results revealed transcriptional activity of 28,335 unique genes from sorghum root and shoot tissues subjected to polyethylene glycol (PEG-induced osmotic stress or exogenous ABA. Differential gene expression analyses in response to osmotic stress and ABA revealed a strong interplay among various metabolic pathways including abscisic acid and 13-lipoxygenase, salicylic acid, jasmonic acid, and plant defense pathways. Transcription factor analysis indicated that groups of genes may be co-regulated by similar regulatory sequences to which the expressed transcription factors bind. We successfully exploited the data presented here in conjunction with published transcriptome analyses for rice, maize, and Arabidopsis to discover more than 50 differentially expressed, drought-responsive gene orthologs for which no function had been previously ascribed. Conclusions The present study provides an initial assemblage of sorghum genes and gene networks regulated by osmotic stress and hormonal treatment. We are providing an RNA-Seq data set and an initial collection of transcription factors, which offer a preliminary look into the cascade of global gene expression patterns that arise in a drought tolerant crop subjected to abiotic stress. These resources will allow scientists to query gene

  2. The p450 monooxygenase BcABA1 is essential for abscisic acid biosynthesis in Botrytis cinerea

    Siewers, V.; Smedsgaard, Jørn; Tudzynski, P.

    2004-01-01

    The phytopathogenic ascomycete Botrytis cinerea is known to produce abscisic acid (ABA), which is thought to be involved in host-pathogen interaction. Biochemical analyses had previously shown that, in contrast to higher plants, the fungal ABA biosynthesis probably does not proceed via carotenoids...

  3. Effect of exogenous abscisic acid on stomatal characteristics during acclimation of in vitro-grown tobacco (Nicotiana tabacum L.) plants

    Tichá, I.; Pospíšilová, Jana

    2008-01-01

    Roč. 133, - (2008), P09-131. ISSN 0031-9317 R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : fluorescence * abscisic acid * antioxidative enzymes Subject RIV: ED - Physiology Impact factor: 2.334, year: 2008

  4. A central role of abscisic acid in stress-regulated carbohydrate metabolism.

    Stefan Kempa

    Full Text Available BACKGROUND: Abiotic stresses adversely affect plant growth and development. The hormone abscisic acid (ABA plays a central role in the response and adaptation to environmental constraints. However, apart from the well established role of ABA in regulating gene expression programmes, little is known about its function in plant stress metabolism. PRINCIPAL FINDINGS: Using an integrative multiparallel approach of metabolome and transcriptome analyses, we studied the dynamic response of the model glyophyte Arabidopsis thaliana to ABA and high salt conditions. Our work shows that salt stress induces complex re-adjustment of carbohydrate metabolism and that ABA triggers the initial steps of carbon mobilisation. SIGNIFICANCE: These findings open new perspectives on how high salinity and ABA impact on central carbohydrate metabolism and highlight the power of iterative combinatorial approaches of non-targeted and hypothesis-driven experiments in stress biology.

  5. Involvement of Polyamine Oxidase in Abscisic Acid induced Cytosolic Antioxidant Defense in Leaves of Maize

    Beibei Xue; Aying Zhang; Mingyi Jiang

    2009-01-01

    Using pharmacological and biochemical approaches, the role of maize polyamine oxidase (MPAO) in abscisic acid (ABA)induced antioxidant defense in leaves of maize (Zea mays L.) plants was investigated. Exogenous ABA treatment enhanced the expression of the MPAO gene and the activities of apoplastic MPAO. Pretreatment with two different inhibitors for apoplastic MPAO partly reduced hydrogen peroxide (H2O2) accumulation induced by ABA and blocked the ABA-induced expression of the antioxidant genes superoxide dismutase 4 and cytosolic ascorbate peroxidase and the activities of the cytosolic antioxidant enzymes. Treatment with spermidine, the optimum substrate of MPAO, also induced the expression and the activities of the antioxidant enzymes, and the upregulation of the antioxidant enzymes was prevented by two inhibitors of MPAO and two scavengers of H2O2. These results suggest that MPAO contributes to ABA-induced cytosolic antioxidant defense through H2O2, a Spd catabolic product.

  6. Exogenous abscisic acid application during grain filling in winter wheat improves cold tolerance of offspring's seedlings

    Li, X.; Cai, J.; Liu, Fulai;

    2014-01-01

    Low temperature seriously depresses seed germination and seedling growth in winter wheat (Triticum aestivum L.). In this study, wheat plants were sprayed with abscisic acid (ABA) and fluridone (inhibitor of ABA biosynthesis) at 19 days after anthesis (DAA) and repeated at 26 DAA. The seeds of those...... plants were harvested, and seed germination and offspring's seedling growth under low temperature were evaluated. The results showed that exogenous ABA application decreased seed weight and slightly reduced seed set and seed number per spike. Under low temperature, seeds from ABA-treated plants showed...... reduced germination rate, germination index, growth of radicle and coleoptile, amylase activity and depressed starch degradation as compared with seeds from non-ABA-treated plants; however, activities of the antioxidant enzymes in both germinating seeds and seedling were enhanced from those exposed to...

  7. Isolation and Crystal Structure of 1′,4′-Trans-diol of Abscisic Acid

    WANG Tian-Shan; ZHOU Jin-Yan; TAN Hong

    2006-01-01

    1 ′,4′-Trans-diol of abscisic acid was isolated from botrytis cinerea as a colorless crystal. The molecular and crystal structures have been determined by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with a = 6.724(3), b = 17.559(6), c =12.265(2) (A), a = β = y = 90°, V = 1448.1(8) (A)3, Z = 4, Dx = 1.222 g/cm3, F(000) = 576 and μ(MoKa) = 0.087 mm-1. The final R = 0.0628 and wR = 0.1604 for 2501 independent reflections with Rint = 0.0160 and 1679 observed reflections with I >2σ(Ⅰ). There are three intermolecular hydrogen bonds in a unit cell.

  8. Effect of abscisic acid and blue radiation on photosynthesis and growth of pea plants

    The effect of abscisic acid (ABA) on the net photosynthetic rate (PN), the ribulose 1,5-bisphosphate carboxylase (RuBPC) and the phosphoenolpyruvate carboxylase (PEPC) activities, the chlorophyll (Chl) content and growth of pea plants (Pisum sativum) grown under ''white'' (WR) or blue radiation (BR), were investigated. BR as compared to WR enhanced PN, the activities of examined enzymes, and Chl content. In spite of higher PN of the plants grown under BR, dry matter of their shoots was lower in comparison with WR. ABA-treated plants grown under both WR and BR showed reduction in PN. ABA had no effect on the activities of both RuBPC and PEPC and the Chl content. Independent on the radiation quality, ABA reduced stem elongation, but did not affect the biomass of whole shoots

  9. Movement of abscisic acid into the apoplast in response to water stress in Xanthium strumarium L

    Cornish, K.; Zeevaart, J.A.D.

    1985-07-01

    The effect of water stress on the redistribution of abscisic acid (ABA) in mature leaves of Xanthium strumarium L. was investigated using a pressure dehydration technique. In both turgid and stressed leaves, the ABA in the xylem exudate, the apoplastic ABA, increased before bulk leaf stress-induced ABA accumulation began. In the initially turgid leaves, the ABA level remained constant in both the apoplast and the leaf as a whole until wilting symptoms appeared. Following turgor loss, sufficient quantities of ABA moved into the apoplast to stimulate stomatal closure. Thus, the initial increase of apoplastic ABA may be relevant to the rapid stomatal closure seen in stressed leaves before their bulk leaf ABA levels rise. Following recovery from water stress, elevated levels of ABA remained in the apoplast after the bulk leaf contents had returned to their prestress values. This apoplastic ABA may retard stomatal reopening during the initial recovery period. 32 references, 5 figures.

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

    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).

  11. The Abscisic Acid Levels of Wheat (Triticum aestivum L. cv. Çakmak 79) Seeds that were Germinated under Heavy Metal(Hg++,Cd++,Cu++)Stress

    MUNZUROĞLU, Ömer; KIRBAĞ ZENGİN, Fikriye; YAHYAGİL, Zübeyde

    2010-01-01

    The purpose of this study was to investigate the level of endogenous abscisic acid of wheat seeds germinated in the presence of 60, 90 and 120 ppm of mercury, cadmium and copper salt solutions for 16 hours in order to see their effects on the germination. The levels of abscisic acid were analysed by High Performance Liquid Chromatography (HPLC). The results indicated that abscisic acid levels were affected by the kind and level of heavy metals used in the experiments. The effects of these tox...

  12. An Abscisic Acid-Independent Oxylipin Pathway Controls Stomatal Closure and Immune Defense in Arabidopsis

    Mondy, Samuel; Tranchimand, Sylvain; Rumeau, Dominique; Boudsocq, Marie; Garcia, Ana Victoria; Douki, Thierry; Bigeard, Jean; Laurière, Christiane; Chevalier, Anne; Castresana, Carmen; Hirt, Heribert

    2013-01-01

    Plant stomata function in innate immunity against bacterial invasion and abscisic acid (ABA) has been suggested to regulate this process. Using genetic, biochemical, and pharmacological approaches, we demonstrate that (i) the Arabidopsis thaliana nine-specific-lipoxygenase encoding gene, LOX1, which is expressed in guard cells, is required to trigger stomatal closure in response to both bacteria and the pathogen-associated molecular pattern flagellin peptide flg22; (ii) LOX1 participates in stomatal defense; (iii) polyunsaturated fatty acids, the LOX substrates, trigger stomatal closure; (iv) the LOX products, fatty acid hydroperoxides, or reactive electrophile oxylipins induce stomatal closure; and (v) the flg22-mediated stomatal closure is conveyed by both LOX1 and the mitogen-activated protein kinases MPK3 and MPK6 and involves salicylic acid whereas the ABA-induced process depends on the protein kinases OST1, MPK9, or MPK12. Finally, we show that the oxylipin and the ABA pathways converge at the level of the anion channel SLAC1 to regulate stomatal closure. Collectively, our results demonstrate that early biotic signaling in guard cells is an ABA-independent process revealing a novel function of LOX1-dependent stomatal pathway in plant immunity. PMID:23526882

  13. 1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds

    Hermann, K.; Meinhard, J.; Dobrev, Petre; Linkies, A.; Pešek, Bedřich; Heß, B.; Macháčková, Ivana; Fischer, U.; Leubner-Metzger, G.

    2007-01-01

    Roč. 58, č. 11 (2007), s. 3047-3060. ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid (ABA) * ABA 8'-hydroxylase (CYP707A) * 1-aminocyclopropane-1-carboxylic acid (ACC) Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  14. K-channels inhibited by hydrogen peroxide mediate abscisic acid signaling in Vicia guard cells

    2001-01-01

    A number of studies show that environmental stress conditions increase abscisic acid (ABA) and hydrogen peroxide (H2O2) levels in plant cells. Despite this central role of ABA in altering stomatal aperture by regulating guard cell ion transport, little is known concerning the relationship between ABA and H2O2 in signal transduction leading to stomatal movement. Epidermal strip bioassay illustrated that ABA-inhibited stomatal opening and ABA-induced stomatal closure were abolished partly by externally added catalase (CAT) or diphenylene iodonium (DPI), which are a H2O2 scavenger and a NADPH oxidase inhibitor respectively. In contrast, internally added CAT or DPI nearly completely or partly reversed ABA-induced closure in half-stoma. Consistent with these results, whole-cell patch-clamp analysis showed that intracellular application of CAT or DPI partly abolished ABA-inhibited inward K+ current across the plasma membrane of guard cells. H2O2 mimicked ABA to inhibit inward K+ current, an effect which was reversed by the addition of ascorbic acid (Vc) in patch clamping micropipettes. These results suggested that H2O2 mediated ABA-induced stomatal movement by targeting inward K+ channels at plasma membrane.

  15. Relative quantification of phosphoproteomic changes in grapevine (Vitis vinifera L.) leaves in response to abscisic acid

    Rattanakan, Supakan; George, Iniga; Haynes, Paul A; Cramer, Grant R

    2016-01-01

    In a previous transcriptomic analysis, abscisic acid (ABA) was found to affect the abundance of a number of transcripts in leaves of Cabernet Sauvignon grapevines with roots that had been exposed to 10 μm ABA for 2 h. Other work has indicated that ABA affects protein abundance and protein phosphorylation as well. In this study we investigated changes in protein abundance and phosphorylation of Cabernet Sauvignon grapevine leaves. Protein abundance was assessed by both label-free and isobaric-label quantitive proteomic methods. Each identified common proteins, but also additional proteins not found with the other method. Overall, several thousand proteins were identified and several hundred were quantified. In addition, hundreds of phosphoproteins were identified. Tens of proteins were found to be affected in the leaf after the roots had been exposed to ABA for 2 h, more than half of them were phosphorylated proteins. Many phosphosites were confirmed and several new ones were identified. ABA increased the abundance of some proteins, but the majority of the proteins had their protein abundance decreased. Many of these proteins were involved in growth and plant organ development, including proteins involved in protein synthesis, photosynthesis, sugar and amino-acid metabolism. This study provides new insights into how ABA regulates plant responses and acclimation to water deficits. PMID:27366326

  16. Phenolic compounds in juice of “Isabel” grape treated with abscisic acid for color improvement

    Yamamoto Lilian Yukari

    2015-01-01

    Full Text Available Isabel grape is the main cultivar used to produce juice in Brazil, which has rusticity and high productivity, but it is deficient in anthocyanins, a pigment responsible for the color. Thus, an alternative is the application of abscisic acid (S-ABA, which is responsible to promote the synthesis of anthocyanins. The aim of this work was to evaluate the phenolic compounds composition in “Isabel” grape juice treated with S-ABA, by HPLC-DAD–ESI-MS/MS technique. The results showed the increasing in total anthocyanin concentration in juices, with S-ABA treatments, as well as the proportion of B-ring tri-substituted anthocyanidins. Regarding total flavonols, differences were only significant in juices obtained in 2012 season. S-ABA treatments did not significantly affect the hydroxycinnamic acid derivatives, flavan-3-ols, resveratrol and antioxidant capacity of juices. Juice from “Isabel” grapes treated with S-ABA provides an enhancement of total anthocyanin concentration, mainly when grapes are treated before or at the onset of véraison.

  17. Hydrogen peroxide modulates abscisic acid signaling in root growth and development in Arabidopsis

    BAI Ling; ZHOU Yun; ZHANG XiaoRan; SONG ChunPeng; Gao MingQing

    2007-01-01

    Exogenous abscisic acid (ABA) can inhibit root growth and promote formation of more root hairs in the root tip of Arabidopsis. However, the molecular mechanisms that underlie root ABA signaling are largely unknown. We report here that hydrogen peroxide (H2O2) reduces the root growth of wild type,and the phenotype of H2O2 on the root growth is similar to ABA response. Meanwhile ABA-induced changes in the morphology of root system can be partly reversed by ascorbic acid in wild type and abolished in NADPH oxidase defective mutant atrbohF and atrbohC. Further, ABA can induce H2O2 accumulation in the root cells and enhance transcription level of OXI1, which is necessary for many more AOS-dependent processes such as root hair growth in Arabidopsis. Our results suggest that H2O2 as an important signal molecule is required for the ABA-regulated root growth and development in Arabidopsis.

  18. Proline and Abscisic Acid Content in Droughted Corn Plant Inoculated with Azospirillum sp. and Arbuscular Mycorrhizae Fungi

    NOVRI YOULA KANDOWANGKO

    2009-03-01

    Full Text Available Plants that undergo drought stress perform a physiological response such as accumulation of proline in the leaves and increased content abscisic acid. A research was conducted to study proline and abscisic acid (ABA content on drought-stressed corn plant with Azospirillum sp. and arbuscular mycorrhizae fungi (AMF inoculated at inceptisol soil from Bogor, West Java. The experiments were carried out in a green house from June up to September 2003, using a factorial randomized block design. In pot experiments, two factors were assigned, i.e. inoculation with Azospirillum (0, 0.50, 1.00, 1.50 ml/pot and inoculation with AMF Glomus manihotis (0, 12.50, 25.00, 37.50 g/pot. The plants were observed during tasseling up to seed filling periods. Results of experiments showed that the interaction between Azospirillum sp. and AMF was synergistically increased proline, however it decreased ABA.

  19. Exogenous application of abscisic acid may improve the growth and yield of sunflower hybrids under drought

    Sunflower genotypes perform differently under different water regimes. Drought stress at various growth stages drastically reduces the growth, development and yield of sunflower hybrids. However, exogenous application of abscisic acid helps in mitigating drought stress by improving growth, development and yield of sunflower. In the present study, three sunflower hybrids viz. DK-4040 (large stature), S-278 (medium stature) and SF-187 (short stature) were exposed to varied irrigation regimes and abscisic acid application schedule i.e. T1: four irrigations with schedule (25DAS, at bud, flower initiation and at achene formation) and with no ABA spray,T/sub 2/: three irrigations with schedule (25DAS, at flower initiation and at achene formation) and with no ABA spray, T/sub 3/: three irrigations with schedule (25DAS, at flower initiation and at achene formation) and with 8 mu MABA spray at bud initiation, T/sub 4/: three irrigations with schedule (25DAS, at bud initiation and at achene formation) and with no ABA spray, T/sub 5/: three irrigations with schedule (25DAS, at bud initiation and at achene formation) and with 8 mu M ABA spray at flower initiation. Experiment was laid out in Randomized Complete Design with factorial arrangement having three replications. ABA application at bud or at flower initiation under drought stress helped in mitigating the detrimental effects by improving growth and yield of sunflower hybrids. Enhancement in drought tolerance of sunflower genotypes was better when ABA was applied at bud initiation stage than that of at flower initiation stage under drought. Improvements in head diameter, achenes per head, 1000-achene weight, achene yield, oil yield, biological yield, harvest index, leaf area index and crop growth rate was recorded. Sunflower hybrid DK-4040 showed more improvement in drought tolerance byfoliar application of ABA under water deficit stress than that of the SF-187 and S-278. It is suggested that sunflower hybrid DK 4040

  20. Cytokinin, auxin, and abscisic acid dynamics during flower development in white and red currants infected with Blackcurrant reversion virus

    Gaudinová, Alena; Malbeck, Jiří; Dobrev, Petre; Kubelková, Darina; Špak, Josef; Vaňková, Radomíra

    2009-01-01

    Roč. 73, č. 6 (2009), s. 119-125. ISSN 0885-5765 R&D Projects: GA MŠk 1P05OC052; GA MŠk OC09084 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50510513 Keywords : Full blossom disease * Cytokinin * Auxin * Abscisic acid Subject RIV: ED - Physiology Impact factor: 1.407, year: 2009

  1. Functional annotation of the transcriptome of Sorghum bicolor in response to osmotic stress and abscisic acid

    Kumari Sunita; Klein Robert R; Olsen Andrew; Monaco Marcela K; Dugas Diana V; Ware Doreen; Klein Patricia E

    2011-01-01

    Abstract Background Higher plants exhibit remarkable phenotypic plasticity allowing them to adapt to an extensive range of environmental conditions. Sorghum is a cereal crop that exhibits exceptional tolerance to adverse conditions, in particular, water-limiting environments. This study utilized next generation sequencing (NGS) technology to examine the transcriptome of sorghum plants challenged with osmotic stress and exogenous abscisic acid (ABA) in order to elucidate genes and gene network...

  2. Abscisic acid enhances tolerance of wheat seedlings to drought and regulates transcript levels of genes encoding ascorbate-glutathione biosynthesis

    Wei, Liting; Wang, Lina; Yang, Yang; Wang, Pengfei; Guo, Tiancai; Kang, Guozhang

    2015-01-01

    Glutathione (GSH) and ascorbate (ASA) are associated with the abscisic acid (ABA)-induced abiotic tolerance in higher plant, however, its molecular mechanism remains obscure. In this study, exogenous application (10 μM) of ABA significantly increased the tolerance of seedlings of common wheat (Triticum aestivum L.) suffering from 5 days of 15% polyethylene glycol (PEG)-stimulated drought stress, as demonstrated by increased shoot lengths and shoot and root dry weights, while showing decreased...

  3. Gene Overexpression and RNA Silencing Tools for the Genetic Manipulation of the S-(+)-Abscisic Acid Producing Ascomycete Botrytis cinerea

    Zhong-Tao Ding; Zhi Zhang; Di Luo; Jin-Yan Zhou; Juan Zhong; Jie Yang; Liang Xiao; Dan Shu; Hong Tan

    2015-01-01

    The phytopathogenic ascomycete Botrytis cinerea produces several secondary metabolites that have biotechnical significance and has been particularly used for S-(+)-abscisic acid production at the industrial scale. To manipulate the expression levels of specific secondary metabolite biosynthetic genes of B. cinerea with Agrobacterium tumefaciens-mediated transformation system, two expression vectors (pCBh1 and pCBg1 with different selection markers) and one RNA silencing vector, pCBSilent1, w...

  4. Gibberellin-to-abscisic acid balances govern development and differentiation of the nucellar projection of barley grains

    Weier, D.; Thiel, J.; Kohl, S.; Tarkowská, Danuše; Strnad, Miroslav; Schaarschmidt, S.; Weschke, W.; Weber, H.; Hause, B.

    2014-01-01

    Roč. 65, č. 18 (2014), s. 5291-5304. ISSN 0022-0957 R&D Projects: GA MŠk LK21306 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Assimilate transfer * barley endosperm * gibberellin-to-abscisic acid balances Subject RIV: EF - Botanics Impact factor: 5.526, year: 2014

  5. Jasmonate signaling involves the abscisic acid receptor PYL4 to regulate metabolic reprogramming in Arabidopsis and tobacco

    Lackman, P.; Gonzalez-Guzman, M.; Tilleman, S.; Carqueijeiro, I.; Perez, A.C.; Moses, T.; Seo, M.; Kanno, Y; Hakkinen, S. T.; Van Montagu, M. C. E.; Thevelein, J M; Maaheimo, H.; Oksman-Caldentey, K.-M.; Rodriguez, P L; Rischer, H.

    2011-01-01

    The phytohormones jasmonates (JAs) constitute an important class of elicitors for many plant secondary metabolic pathways. However, JAs do not act independently but operate in complex networks with crosstalk to several other phytohormonal signaling pathways. Here, crosstalk was detected between the JA and abscisic acid (ABA) signaling pathways in the regulation of tobacco (Nicotiana tabacum) alkaloid biosynthesis. A tobacco gene from the PYR/PYL/RCAR family, NtPYL4, the expression of which is...

  6. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Valluru, Ravi; Davies, William John; Reynolds, Matthew; Dodd, Ian Charles

    2016-01-01

    Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ...

  7. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Ravi eValluru; William J eDavies; Matthew P eReynolds; Ian C eDodd

    2016-01-01

    Although plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous A...

  8. Crystallization and preliminary X-ray diffraction studies of the abscisic acid receptor PYL3 and its complex with pyrabactin

    Crystals of the abscisic acid receptor PYL3 and of the PYL3–pyrabactin complex were obtained and optimized in order to obtain high-quality diffraction data. Diffraction data sets were collected and processed to 2.5 and 1.83 Å resolution, respectively. Abscisic acid (ABA) modulates many developmental processes and responses to environmental stress. Recently, a family of pyrabactin resistance-like proteins (PYLs) in Arabidopsis thaliana were identified to be abscisic acid receptors. Although the 14 PYLs members share a similar sequence identity, they exhibit different responses toward pyrabactin. Apo-PYL3 is a dimer; however, its oligomeric state changes greatly on the addition of pyrabactin. Moreover, pyrabactin binds dimeric PYL3 in a nonproductive mode which prevents receptor activation and inhibition of PP2Cs. Here, the expression, purification and crystallization of apo-PYL3 and of PYL3 complexed with pyrabactin are reported. Diffraction data were optimized to 2.5 Å resolution for apo-PYL3 and to 1.83 Å resolution for PYL3–pyrabactin. The crystals of apo-PYL3 and PYL3–pyrabactin belonged to space groups P41212 and P212121, respectively

  9. Stomatal response to abscisic Acid is a function of current plant water status.

    Tardieu, F; Davies, W J

    1992-02-01

    We investigated, under laboratory and field conditions, the possibility that increasing abscisic acid (ABA) concentrations and decreasing water potentials can interact in their effects on stomata. One experiment was carried out with epidermal pieces of Commelina communis incubated in media with a variety of ABA and polyethylene glycol concentrations. In the media without ABA, incubation in solutions with water potentials between -0.3 and -1.5 megapascals had no significant effect on stomatal aperture. Conversely, the sensitivity of stomatal aperture to ABA was trebled in solutions at -1.5 megapascals compared with sensitivity at -0.3 megapascals. The effect of the change in sensitivity was more important than the absolute effect of ABA at the highest water potential. In a field experiment, sensitivity of maize stomatal conductance to the concentration of ABA in the xylem sap varied strongly with the time of the day. We consider that the most likely explanation for this is the influence of a change in leaf or epidermal water potential that accompanies an increase in irradiance and saturation deficit as the day progresses. These observations suggest that epidermal water relations may act as a modulator of the responses of stomata to ABA. We argue that such changes must be taken into account in studies or modeling of plant responses to drought stress. PMID:16668674

  10. Abscisic Acid Control of rbcS and cab Transcription in Tomato Leaves.

    Bartholomew, D M; Bartley, G E; Scolnik, P A

    1991-05-01

    Leaves of tomato (Lycopersicon esculentum) plants grown in soil in which moisture was lowered from field capacity to levels approaching permanent wilting point show a 10-fold increase in abscisic acid (ABA) and a 60 to 70 percent decrease in rbcS and cab steady-state mRNA levels. As indicated by transcription run-on experiments, the effect occurs primarily at the transcriptional level. Similar water deficit had only a minor effect on ABA level and on rbcS and cab expression in leaves of sitiens, an ABA mutant of tomato. Expression of rbcL, the chloroplast gene coding for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase, is not affected by water stress. Application of exogenous ABA results in decreased rbcS and cab expression in both wild-type and sitiens leaves. Analysis of the expression of individual members of the rbcS gene family indicates that under water-deficit conditions, expression derives primarily from only three of the five rbcS genes. Effects of dark adaptation and water deficit are additive for cab but not for rbcS expression. These results support the hypothesis that, at least under water-deficit conditions, ABA or a derivative thereof mediates a negative regulation of rbcS and cab transcription in tomato plants. PMID:16668167

  11. The Dynamics of Embolism Refilling in Abscisic Acid (ABA-Deficient Tomato Plants

    Francesca Secchi

    2012-12-01

    Full Text Available Plants are in danger of embolism formation in xylem vessels when the balance between water transport capacity and transpirational demand is compromised. To maintain this delicate balance, plants must regulate the rate of transpiration and, if necessary, restore water transport in embolized vessels. Abscisic acid (ABA is the dominant long-distance signal responsible for plant response to stress, and it is possible that it plays a role in the embolism/refilling cycle. To test this idea, a temporal analysis of embolism and refilling dynamics, transpiration rate and starch content was performed on ABA-deficient mutant tomato plants. ABA-deficient mutants were more vulnerable to embolism formation than wild-type plants, and application of exogenous ABA had no effect on vulnerability. However, mutant plants treated with exogenous ABA had lower stomatal conductance and reduced starch content in the xylem parenchyma cells. The lower starch content could have an indirect effect on the plant’s refilling activity. The results confirm that plants with high starch content (moderately stressed mutant plants were more likely to recover from loss of water transport capacity than plants with low starch content (mutant plants with application of exogenous ABA or plants experiencing severe water stress. This study demonstrates that ABA most likely does not play any direct role in embolism refilling, but through the modulation of carbohydrate content, it could influence the plant’s capacity for refilling.

  12. Supplementation with Abscisic Acid Reduces Malaria Disease Severity and Parasite Transmission.

    Glennon, Elizabeth K K; Adams, L Garry; Hicks, Derrick R; Dehesh, Katayoon; Luckhart, Shirley

    2016-06-01

    Nearly half of the world's population is at risk for malaria. Increasing drug resistance has intensified the need for novel therapeutics, including treatments with intrinsic transmission-blocking properties. In this study, we demonstrate that the isoprenoid abscisic acid (ABA) modulates signaling in the mammalian host to reduce parasitemia and the formation of transmissible gametocytes and in the mosquito host to reduce parasite infection. Oral ABA supplementation in a mouse model of malaria was well tolerated and led to reduced pathology and enhanced gene expression in the liver and spleen consistent with infection recovery. Oral ABA supplementation also increased mouse plasma ABA to levels that can signal in the mosquito midgut upon blood ingestion. Accordingly, we showed that supplementation of a Plasmodium falciparum-infected blood meal with ABA increased expression of mosquito nitric oxide synthase and reduced infection prevalence in a nitric oxide-dependent manner. Identification of the mechanisms whereby ABA reduces parasite growth in mammals and mosquitoes could shed light on the balance of immunity and metabolism across eukaryotes and provide a strong foundation for clinical translation. PMID:27001761

  13. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  14. Role of abscisic acid (aba) in modulating the responses of two apple rootstocks to drought stress

    Drought stress is considered as the main limiting factor for apple (Malus domestica L.) production in some semi-arid areas of China. In this study, we investigated the modulation role of abscisic acid (ABA) and fluridone (ABA synthesis inhibitor) on water relations and antioxidant enzyme system in 2-year-old seedlings of two apple rootstocks i.e. Malus sieversii (Ledeb.) Roem. (MS) and Malus hupehensis (Pamp.) Rehd. (MH). Drought stress induced ion leakage, accumulation of malondiadehyde (MDA) and decreases in leaf water potential and relative water content (RWC) in both rootstocks, which were significantly alleviated by exogenous ABA application. Drought stress also induced markedly increases in endogenous ABA content and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), and glutathione reductase (GR), to a greater magnitude in MS as compared to MH rootstock. Concentration of 100 mol/L and 50 mol/L ABA had the most positive effects on drought-stressed rootstocks of MS and MH, respectively. Spraying optimum exogenous ABA contributed to enhancement in most of the above antioxidant enzymes activities but reduction in content of MDA and maintained the appropriate leaf water potential and RWC in both rootstocks. Pretreatment with fluridone aggravated ion leakage and the accumulation of MDA in two apple rootstocks under drought stress, which was overcome by exogenous ABA application to some extent. In conclusion, the endogenous ABA was probably involved in the regulation of two apple rootstocks in responses to drought stress. (author)

  15. Transcriptomic insights into antagonistic effects of gibberellin and abscisic acid on petal growth in Gerbera hybrida.

    Li, Lingfei; Zhang, Wenbin; Zhang, Lili; Li, Na; Peng, Jianzong; Wang, Yaqin; Zhong, Chunmei; Yang, Yuping; Sun, Shulan; Liang, Shan; Wang, Xiaojing

    2015-01-01

    Petal growth is central to floral morphogenesis, but the underlying genetic basis of petal growth regulation is yet to be elucidated. In this study, we found that the basal region of the ray floret petals of Gerbera hybrida was the most sensitive to treatment with the phytohormones gibberellin (GA) and abscisic acid (ABA), which regulate cell expansion during petal growth in an antagonistic manner. To screen for differentially expressed genes (DEGs) and key regulators with potentially important roles in petal growth regulation by GA or/and ABA, the RNA-seq technique was employed. Differences in global transcription in petals were observed in response to GA and ABA and target genes antagonistically regulated by the two hormones were identified. Moreover, we also identified the pathways associated with the regulation of petal growth after application of either GA or ABA. Genes relating to the antagonistic GA and ABA regulation of petal growth showed distinct patterns, with genes encoding transcription factors (TFs) being active during the early stage (2 h) of treatment, while genes from the "apoptosis" and "cell wall organization" categories were expressed at later stages (12 h). In summary, we present the first study of global expression patterns of hormone-regulated transcripts in G. hybrida petals; this dataset will be instrumental in revealing the genetic networks that govern petal morphogenesis and provides a new theoretical basis and novel gene resources for ornamental plant breeding. PMID:25852718

  16. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    Melcher, Karsten; Ng, Ley-Moy; Zhou, X Edward; Soon, Fen-Fen; Xu, Yong; Suino-Powell, Kelly M; Park, Sang-Youl; Weiner, Joshua J; Fujii, Hiroaki; Chinnusamy, Viswanathan; Kovach, Amanda; Li, Jun; Wang, Yonghong; Li, Jiayang; Peterson, Francis C; Jensen, Davin R; Yong, Eu-Leong; Volkman, Brian F; Cutler, Sean R; Zhu, Jian-Kang; Xu, H Eric; (NU Sinapore); (Van Andel); (MCW); (UCR); (Chinese Aca. Sci.)

    2010-01-12

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved β-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling.

  17. Proanthocyanidins Inhibit Seed Germination by Maintaining a High Level of Abscisic Acid in Arabidopsis thaliana

    Liguo Jia; Jianhua Zhang; Qiuyu Wu; Nenghui Ye; Rui Liu; Lu Shi; Weifeng Xu; Hui Zhi; A. N. M. Rubaiyath Bin Rahman; Yiji Xia

    2012-01-01

    Proanthocyanidins (PAs) are the main products of the flavonoid biosynthetic pathway in seeds,but their biological function during seed germination is still unclear.We observed that seed germination is delayed with the increase of exogenous PA concentration in Arabidopsis.A similar inhibitory effect occurred in peeled Brassica napus seeds,which was observed by measuring radicle elongation.Using abscisic acid (ABA),a biosynthetic and metabolic inhibitor,and gene expression analysis by real-time polymerase chain reaction,we found that the inhibitory effect of PAs on seed germination is due to their promotion of ABA via de novo biogenesis,rather than by any inhibition of its degradation.Consistent with the relationship between PA content and ABA accumulation in seeds,PA-deficient mutants maintain a lower level of ABA compared with wild-types during germination.Our data suggest that PA distribution in the seed coat can act as a doorkeeper to seed germination.PA regulation of seed germination is mediated by the ABA signaling pathway.

  18. UV-induced cross-linking of abscisic acid to binding proteins

    Conditions for UV-induced cross-linking of abscisic acid (ABA) through its enone chromophore to binding proteins were evaluated. The effects of a UV-light band between 260 and 530 nm on both unconjugated and protein-conjugated ABA, as well as on anti-ABA antibodies as models of ABA-binding proteins were determined. UV irradiation caused both isomerization and photolysis of ABA, but increasing the lower irradiation boundary to 345 nm strongly reduced photolysis and largely prevented isomerization. When conjugated to alkaline phosphatase (AP), ABA remained stable when using either a 320 or a 345 nm filter. At these wavelengths both binding of ABA to antibodies as well as AP enzymatic activity were maintained. UV-induced cross-linking of monoclonal anti-ABA antibodies to immobilized ABA was analysed by immunoassays. Optimal cross-linking was achieved after a 5 min irradiation period at 0°, using a long pass, cut-on filter to quench wavelengths below 290 nm. This cross-linking faithfully reflected cognate binding activity. (author)

  19. Reactive oxygen species, abscisic acid and ethylene interact to regulate sunflower seed germination.

    El-Maarouf-Bouteau, Hayat; Sajjad, Yasar; Bazin, Jérémie; Langlade, Nicolas; Cristescu, Simona M; Balzergue, Sandrine; Baudouin, Emmanuel; Bailly, Christophe

    2015-02-01

    Sunflower (Helianthus annuus L.) seed dormancy is regulated by reactive oxygen species (ROS) and can be alleviated by incubating dormant embryos in the presence of methylviologen (MV), a ROS-generating compound. Ethylene alleviates sunflower seed dormancy whereas abscisic acid (ABA) represses germination. The purposes of this study were to identify the molecular basis of ROS effect on seed germination and to investigate their possible relationship with hormone signalling pathways. Ethylene treatment provoked ROS generation in embryonic axis whereas ABA had no effect on their production. The beneficial effect of ethylene on germination was lowered in the presence of antioxidant compounds, and MV suppressed the inhibitory effect of ABA. MV treatment did not alter significantly ethylene nor ABA production during seed imbibition. Microarray analysis showed that MV treatment triggered differential expression of 120 probe sets (59 more abundant and 61 less abundant genes), and most of the identified transcripts were related to cell signalling components. Many transcripts less represented in MV-treated seeds were involved in ABA signalling, thus suggesting an interaction between ROS and ABA signalling pathways at the transcriptional level. Altogether, these results shed new light on the crosstalk between ROS and plant hormones in seed germination. PMID:24811898

  20. Ubiquitin-specific protease 24 negatively regulates abscisic acid signalling in Arabidopsis thaliana.

    Zhao, Jinfeng; Zhou, Huapeng; Zhang, Ming; Gao, Yanan; Li, Long; Gao, Ying; Li, Ming; Yang, Yuhong; Guo, Yan; Li, Xueyong

    2016-02-01

    Abscisic acid (ABA) is an important plant hormone integrating environmental stress and plant growth. Protein ubiquitination and deubiquitination are reversible processes catalysed by E3 ubiquitin ligase and deubiquitinating enzyme, respectively. Lots of E3 ubiquitin ligase and transcriptional factors modified by ubiquitination were reported to modulate ABA signalling. However, no deubiquitinating enzyme has been identified that functions in ABA signalling until now. Here, we isolated an ABA overly sensitive mutant, ubp24, in which the gene encoding ubiquitin-specific protease 24 (UBP24, At4g30890) was disrupted by a T-DNA insertion. The ubp24 mutant was hypersensitive to ABA and salt stress in both post-germinative growth and seedling growth. However, stomata closure in the ubp24 mutant was less sensitive to ABA, and the ubp24 mutant showed drought sensitivity. UBP24 possessed deubiquitinating enzyme activity, and the activity was essential for UBP24 function. Additionally, UBP24 formed homodimer in vivo. UBP24 was genetically upstream of ABI2, and the phosphatase activity of protein phosphatase 2C was decreased in the ubp24 mutant compared with the wild type in the presence of ABA. These results uncover an important regulatory role for the ubiquitin-specific protease in response to ABA and salt stress in plant. PMID:26290265

  1. Functional analysis of a Lemna gibba rbcS promoter regulated by abscisic acid and sugar

    Youru Wang

    2013-04-01

    Photosynthesis-associated nuclear genes (PhANGs) are able to respond to multiple environmental and developmental signals, including light, sugar and abscisic acid (ABA). PhANGs have been extensively studied at the level of transcriptional regulation, and several cis-acting elements important for light responsiveness have been identified in their promoter sequences. However, the regulatory elements involved in sugar and ABA regulation of PhANGs have not been completely characterized. A ribulose-1,5-bisphosphate carboxylase small subunit gene (rbcS) promoter (SSU5C promoter) was isolated from duckweed (Lemna gibba). A series of SSU5C promoter 5′ deletion fragments were fused to an intron–gus gene, and transgenic tobacco suspension cell lines were generated. Assay of tobacco suspension cell line harbouring the complete promoter in the fusion construct indicated that SSU5C promoter was negatively regulated by sugar and ABA under the condition of regular photoperiod. 5′ deletion analysis of SSU5C promoter in transgenic tobacco suspension cell lines confirmed that a region between positions $-310$ and $-152$ included the ABA-response region, and that sugar-response cis-acting elements might be located in the region between $-152$ and $-117$. Taken together, our results confirmed that the cis-regulatory region responsible for repression by ABA and sugar in the SSU5C promoter was located between $-310$ and $-117$.

  2. Postharvest Exogenous Application of Abscisic Acid Reduces Internal Browning in Pineapple.

    Zhang, Qin; Liu, Yulong; He, Congcong; Zhu, Shijiang

    2015-06-10

    Internal browning (IB) is a postharvest physiological disorder causing economic losses in pineapple, but there is no effective control measure. In this study, postharvest application of 380 μM abscisic acid (ABA) reduced IB incidence by 23.4-86.3% and maintained quality in pineapple fruit. ABA reduced phenolic contents and polyphenol oxidase and phenylalanine ammonia lyase activities; increased catalase and peroxidase activities; and decreased O2(·-), H2O2, and malondialdehyde levels. This suggests ABA could control IB through inhibiting phenolics biosynthesis and oxidation and enhancing antioxidant capability. Furthermore, the efficacy of IB control by ABA was not obviously affected by tungstate, ABA biosynthesis inhibitor, nor by diphenylene iodonium, NADPH oxidase inhibitor, nor by lanthanum chloride, calcium channel blocker, suggesting that ABA is sufficient for controlling IB. This process might not involve H2O2 generation, but could involve the Ca(2+) channels activation. These results provide potential for developing effective measures for controlling IB in pineapple. PMID:26007196

  3. Interactions between ethylene, abscisic acid and cytokinin during germination and seedling establishment in Arabidopsis

    Veeraputhiran Subbiah; Karingu Janardhan Reddy

    2010-09-01

    In order to investigate the interaction of the plant hormones ethylene, abscisic acid (ABA) and cytokinin in seed germination and early seedling development, we studied germination in ethylene-related mutants of Arabidopsis. Mutations in the genes etr1 and ein2, which reduce ethylene responses, showed increased dormancy and a delay in germination in comparison with wild type. Mutations in etr1, ein2 and ein6 also resulted in increased sensitivity to ABA with respect to inhibition of germination. Conversely, mutations in ctr1 and eto3, which lead to an increased ethylene response and overproduction of ethylene, respectively, decreased sensitivity to ABA during germination. Increased ABA sensitivity was also effected in wild type seeds by the presence during germination of AgNO3, an inhibitor of ethylene action. The addition of the cytokinin N-6 benzyl adenine (BA) reversed the increased sensitivity of ethylene-resistant mutants to ABA. The action of cytokinin in reversing increased ABA sensitivity of ethylene-resistant mutants also suggests that at least part of the action of cytokinin in promoting germination is independent of its role in stimulating ethylene production. These observations further extend the evidence in support of interaction between ethylene, ABA and cytokinin signalling in controlling seed germination and early seedling development in Arabidopsis.

  4. Growth, Gas Exchange, Abscisic Acid, and Calmodulin Response to Salt Stress in Three Poplars

    2006-01-01

    In the present study, we investigated the effects of increasing salinity on growth, gas exchange, abscisic acid(ABA), calmodulin (CAM), and the relevance to salt tolerance in seedlings of Populus euphratica Oliv. and cuttings of P. "pupularis 35-44" (P. popularis) and P. x euramericana cv. 1-214 (P. cv. Italica). The relative growth rates of shoot height (RGRH) for P. cv. Italica and P. popularis were severely reduced by increasing salt stress,whereas the growth reduction was relatively less in P. euphratica. Similarly, P. euphratica maintained higher net photosynthetic rates (Pn) and unit transpiration rates (TRN) than P. cv. Italica and P. popularis under conditions of higher salinity. Salinity caused a significant increase in leaf ABA and CaM in the three genotypes after the onset of stress, but NaCl-induced ABA and CaM accumulation was more pronounced in P. euphratica,suggesting that P. euphratica plants are more sensitive in sensing soil salinity than the other two poplars.Furthermore, P. euphratica maintained relatively higher ABA and CaM concentrations under conditions of high salinity. The higher capacity to synthesize stress signals, namely ABA and CaM, in P. euphratica and the contribution of this to the salt resistance of P. euphratica are discussed.

  5. Microarray Analysis of Transcriptional Responses to Abscisic Acid and Salt Stress in Arabidopsis thaliana

    Yucheng Wang

    2013-05-01

    Full Text Available Abscisic acid (ABA plays a crucial role in plant responses to abiotic stress. To investigate differences in plant responses to salt and ABA stimulus, differences in gene expression in Arabidopsis in response to salt and ABA were compared using an Agilent oligo microarray. A total of 144 and 139 genes were significantly up- and downregulated, respectively, under NaCl stress, while 406 and 381 genes were significantly up- and downregulated, respectively, under ABA stress conditions. In addition, 31 genes were upregulated by both NaCl and ABA stresses, and 23 genes were downregulated by these stressors, suggesting that these genes may play similar roles in plant responses to salt and ABA stress. Gene ontology (GO analysis revealed four subgroups of genes, including genes in the GO categories “Molecular transducer activity”, “Growth”, “Biological adhesion” and “Pigmentation”, which were expressed in response to ABA stress but not NaCl stress. In addition, genes that play specific roles during salt or ABA stress were identified. Our results may help elucidate differences in the response of plants to salt and ABA stress.

  6. Production of Polyamines Is Enhanced by Endogenous Abscisic Acid in Maize Seedlings Subjected to Salt Stress

    Jun LIU; Ming-Yi JIANG; Yi-Feng ZHOU; You-Liang LIU

    2005-01-01

    It is known that salt stress and exogenously applied abscisic acid (ABA) can enhance the polyamine content in plants and that salt stress itself can lead to an increase in endogenous ABA production.In the present study, the relationships between salt-induced ABA and polyamine accumulation were investigated using ABA-deficient mutant (vp5/vp5) maize (Zea mays L.) seedlings and ABA and polyamine :biosynthesis inhibitors. The results show that reduced endogenous ABA levels, as a result of either the mutation or by using a chemical inhibitor (sodium tungstate), also reduced the accumulation of polyamines in salt-stressed leaves of maize seedlings. The polyamine synthesis inhibitors D-arginine and αdifluoromethylornithine also reduced the polyamine content of the leaves of maize seedling under salt stress. Both ABA and polyamine enhanced the dry weight accumulation of salt-stressed seedlings and also increased the activities of the two dominant tonoplast membrane enzymes, H+-ATPase and H+-PPase, when plants were under salt stress. The results suggest that salt stress induces an increase in endogenous ABA levels, which then enhances polyamine synthesis. Such responses may increase a plant's tolerance to salt.

  7. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    Melcher, Karsten

    2009-12-03

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved ?-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling. © 2009 Macmillan Publishers Limited. All rights reserved.

  8. Abscisic acid - an overlooked player in plant-microbe symbioses formation?

    Stec, Natalia; Banasiak, Joanna; Jasiński, Michał

    2016-01-01

    Abscisic acid (ABA) is an ubiquitous plant hormone and one of the foremost signalling molecules, controlling plants' growth and development, as well as their response to environmental stresses. To date, the function of ABA has been extensively investigated as an abiotic stress molecule which regulates the plants' water status. However, in the context of symbiotic associations, ABA is less recognized. In contrast to well-described auxin/cytokinin and gibberellin/strigolactone involvement in symbioses, ABA has long been underestimated. Interestingly, ABA emerges as an important player in arbuscular mycorrhiza and legume-rhizobium symbiosis. The plant's use of stress hormones like ABA in regulation of those interactions directly links the efficiency of these processes to the environmental status of the plant, notably during drought stress. Here we provide an overview of ABA interplay in beneficial associations of plants with microorganisms and propose ABA as a potential factor determining whether the investment in establishing the interaction is higher than the profit coming from it. PMID:26828669

  9. Application time and concentrations of abscisic acid on the color development of ‘Isabel’ grapes

    Renata Koyama

    2014-09-01

    Full Text Available The grape ‘Isabel’ main cultivar used for juice production in Brazil has a deficiency of coloring and an alternative is the application of abscisic acid (S-ABA, since the accumulation of anthocyanins, pigment that interferes in the color of berries, appears to be regulated by this growth regulator. The aim of this research was to evaluate the effect of different concentrations of S-ABA applied at different times in the clusters of ‘Isabel’ grapes to improve their color attributes. The vines were conducted in a vertical support structure, spaced 2 x 1 m in cordon. A randomized block design was used as a statistical model, with 4 replications and 5 treatments, as follows: control; S-ABA 200 mg L-1 applied seven days after veraison (DAV; S-ABA 400 mg L-1 7 DAV; S-ABA 200 mg L-1 7 DAV +S-ABA 200 mg L-1 10 days before harvest (DBH; S-ABA 400 mg L-1 7 DAV + 400 mg L-1 10 DBH. At harvest the following variables were evaluated: mass and diameter of the berries, mass and length of the clusters; soluble solids (SS, titratable acidity (TA and maturation index (TSS/TA. It was also evaluated the concentration of anthocyanins and total polyphenol index in wine and juice, prepared by the extraction method of the pan and color of the berries by colorimetry. The application of S-ABA did not influence the physical characteristics of the grapes, however, favored the increase of SS and SS/TA of the berries, except for the concentration of 200 mg L-1 applied seven days after veraison. The S-ABA has an effect on improving the content of anthocyanins of the berries and the juice of the ‘Isabel’ grape, mainly in the 400 mg L-1 applied 7 DAV + 10 DBH, besides enabling the improvement in the color attribute of berries.

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

    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.

  11. LTP3 contributes to disease susceptibility in Arabidopsis by enhancing abscisic acid (ABA) biosynthesis.

    Gao, Shan; Guo, Wenya; Feng, Wen; Liu, Liang; Song, Xiaorui; Chen, Jian; Hou, Wei; Zhu, Hongxia; Tang, Saijun; Hu, Jian

    2016-04-01

    Several plant lipid transfer proteins (LTPs) act positively in plant disease resistance. Here, we show that LTP3 (At5g59320), a pathogen and abscisic acid (ABA)-induced gene, negatively regulates plant immunity in Arabidopsis. The overexpression of LTP3 (LTP3-OX) led to an enhanced susceptibility to virulent bacteria and compromised resistance to avirulent bacteria. On infection of LTP3-OX plants with Pseudomonas syringae pv. tomato, genes involved in ABA biosynthesis, NCED3 and AAO3, were highly induced, whereas salicylic acid (SA)-related genes, ICS1 and PR1, were down-regulated. Accordingly, in LTP3-OX plants, we observed increased ABA levels and decreased SA levels relative to the wild-type. We also showed that the LTP3 overexpression-mediated enhanced susceptibility was partially dependent on AAO3. Interestingly, loss of function of LTP3 (ltp3-1) did not affect ABA pathways, but resulted in PR1 gene induction and elevated SA levels, suggesting that LTP3 can negatively regulate SA in an ABA-independent manner. However, a double mutant consisting of ltp3-1 and silent LTP4 (ltp3/ltp4) showed reduced susceptibility to Pseudomonas and down-regulation of ABA biosynthesis genes, suggesting that LTP3 acts in a redundant manner with its closest homologue LTP4 by modulating the ABA pathway. Taken together, our data show that LTP3 is a novel negative regulator of plant immunity which acts through the manipulation of the ABA-SA balance. PMID:26123657

  12. An Ancestral Role for CONSTITUTIVE TRIPLE RESPONSE1 Proteins in Both Ethylene and Abscisic Acid Signaling.

    Yasumura, Yuki; Pierik, Ronald; Kelly, Steven; Sakuta, Masaaki; Voesenek, Laurentius A C J; Harberd, Nicholas P

    2015-09-01

    Land plants have evolved adaptive regulatory mechanisms enabling the survival of environmental stresses associated with terrestrial life. Here, we focus on the evolution of the regulatory CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) component of the ethylene signaling pathway that modulates stress-related changes in plant growth and development. First, we compare CTR1-like proteins from a bryophyte, Physcomitrella patens (representative of early divergent land plants), with those of more recently diverged lycophyte and angiosperm species (including Arabidopsis [Arabidopsis thaliana]) and identify a monophyletic CTR1 family. The fully sequenced P. patens genome encodes only a single member of this family (PpCTR1L). Next, we compare the functions of PpCTR1L with that of related angiosperm proteins. We show that, like angiosperm CTR1 proteins (e.g. AtCTR1 of Arabidopsis), PpCTR1L modulates downstream ethylene signaling via direct interaction with ethylene receptors. These functions, therefore, likely predate the divergence of the bryophytes from the land-plant lineage. However, we also show that PpCTR1L unexpectedly has dual functions and additionally modulates abscisic acid (ABA) signaling. In contrast, while AtCTR1 lacks detectable ABA signaling functions, Arabidopsis has during evolution acquired another homolog that is functionally distinct from AtCTR1. In conclusion, the roles of CTR1-related proteins appear to have functionally diversified during land-plant evolution, and angiosperm CTR1-related proteins appear to have lost an ancestral ABA signaling function. Our study provides new insights into how molecular events such as gene duplication and functional differentiation may have contributed to the adaptive evolution of regulatory mechanisms in plants. PMID:26243614

  13. Abscisic Acid Induces Rapid Reductions in Mesophyll Conductance to Carbon Dioxide.

    Giuseppe Sorrentino

    Full Text Available The rate of photosynthesis (A of plants exposed to water deficit is a function of stomatal (gs and mesophyll (gm conductance determining the availability of CO2 at the site of carboxylation within the chloroplast. Mesophyll conductance often represents the greatest impediment to photosynthetic uptake of CO2, and a crucial determinant of the photosynthetic effects of drought. Abscisic acid (ABA plays a fundamental role in signalling and co-ordination of plant responses to drought; however, the effect of ABA on gm is not well-defined. Rose, cherry, olive and poplar were exposed to exogenous ABA and their leaf gas exchange parameters recorded over a four hour period. Application with ABA induced reductions in values of A, gs and gm in all four species. Reduced gm occurred within one hour of ABA treatment in three of the four analysed species; indicating that the effect of ABA on gm occurs on a shorter timescale than previously considered. These declines in gm values associated with ABA were not the result of physical changes in leaf properties due to altered turgor affecting movement of CO2, or caused by a reduction in the sub-stomatal concentration of CO2 (Ci. Increased [ABA] likely induces biochemical changes in the properties of the interface between the sub-stomatal air-space and mesophyll layer through the actions of cooporins to regulate the transport of CO2. The results of this study provide further evidence that gm is highly responsive to fluctuations in the external environment, and stress signals such as ABA induce co-ordinated modifications of both gs and gm in the regulation of photosynthesis.

  14. Influence Mechanism of Endogenous Abscisic Acid on Storage Softening Process of Hardy Kiwifruit

    Li Shuqian

    2014-01-01

    Full Text Available In order to study the relation of Abscisic Acid (ABA with other biochemistry factors during hardy kiwifruit softening process. The changing trend of ABA under the fruits storage conditions of 20 and 0C was analyzed. A conclusion is drawn as below: During storage under 20C, it shows the highest content of ABA in 4 days to 222.19 &mu g/L, which reaches the almost same content in 3 and 5 days. The value keeps inclining since 5 days and decline rate is lower in 7 and 8 days. The lowest value is reached to 20.88 &mug/L in 10 days. During storage under 0C, ABA content is at a relatively high level but shows the slow down trend. ABA content falls greatly from 9 to 11 days. After this period, ABA content still follows up-trend and declining then. The peak appears in 15 days to 90.49 &mug/L, but it is lower than that in the first nine days. Moreover, peak during storage in environment under 0C is lower than that during the storage in environment at normal temperature, accordingly delaying fruit softening. As the ABA content rises to the highest level, the fruit hardness drops drastically. When ABA content slightly changes, the hardness decreases gently. ABA content is featured that same changing trend of ethylene content, respiratory intensity, pectase content and amylase content. Moreover, ABA has the same peak appearance time as amylase but it is later than appearance of both pectase and ethylene, they basically match each other. The rule of peak appearance time is not obvious for ABA and amylase. Mutual inhibition exists between peak appearance time of ABA and respiratory intensity. Quick ABA rise is accompanied with slow amylase rise and vice versa.

  15. Abscisic acid and stress signals induce Viviparous1 expression in seed and vegetative tissues of maize.

    Cao, Xueyuan; Costa, Liliana M; Biderre-Petit, Corinne; Kbhaya, Bouchab; Dey, Nrisingha; Perez, Pascual; McCarty, Donald R; Gutierrez-Marcos, Jose F; Becraft, Philip W

    2007-02-01

    Viviparous1 (Vp1) encodes a B3 domain-containing transcription factor that is a key regulator of seed maturation in maize (Zea mays). However, the mechanisms of Vp1 regulation are not well understood. To examine physiological factors that may regulate Vp1 expression, transcript levels were monitored in maturing embryos placed in culture under different conditions. Expression of Vp1 decreased after culture in hormone-free medium, but was induced by salinity or osmotic stress. Application of exogenous abscisic acid (ABA) also induced transcript levels within 1 h in a dose-dependent manner. The Vp1 promoter fused to beta-glucuronidase or green fluorescent protein reproduced the endogenous Vp1 expression patterns in transgenic maize plants and also revealed previously unknown expression domains of Vp1. The Vp1 promoter is active in the embryo and aleurone cells of developing seeds and, upon drought stress, was also found in phloem cells of vegetative tissues, including cobs, leaves, and stems. Sequence analysis of the Vp1 promoter identified a potential ABA-responsive complex, consisting of an ACGT-containing ABA response element (ABRE) and a coupling element 1-like motif. Electrophoretic mobility shift assay confirmed that the ABRE and putative coupling element 1 components specifically bound proteins in embryo nuclear protein extracts. Treatment of embryos in hormone-free Murashige and Skoog medium blocked the ABRE-protein interaction, whereas exogenous ABA or mannitol treatment restored this interaction. Our data support a model for a VP1-dependent positive feedback mechanism regulating Vp1 expression during seed maturation. PMID:17208960

  16. Abscisic acid metabolism in relation to water stress and leaf age in Xanthium strumarium

    Cornish, K.; Zeevaart, J.A.D.

    1984-12-01

    Intact plants of Xanthium strumarium L. were subjected to a water stress-recovery cycle. As the stress took effect, leaf growth ceased and stomatal resistance increased. The mature leaves then wilted, followed by the half expanded ones. Water, solute, and pressure potentials fell steadily in all leaves during the rest of the stress period. After 3 days, the young leaves lost turgor and the plants were rewatered. All the leaves rapidly regained turgor and the younger ones recommenced elongation. Stomatal resistance declined, but several days elapsed before pre-stress values were attained. Abscisic aid (ABA) and phaseic acid (PA) levels rose in all the leaves after the mature ones wilted. ABA-glucose ester (ABA-GE) levels increased to a lesser extent, and the young leaves contained little of this conjugate. PA leveled off in the older leaves during the last 24 hours of stress, and ABA levels declined slightly. The young leaves accumulated ABA and PA throughout the stress period and during the 14-hour period immediately following rewatering. The ABA and PA contents, expressed per unit dry weight, were highest in the young leaves. Upon rewatering, large quantities of PA appeared in the mature leaves as ABA levels fell to the pre-stress level within 14 hours. In the half expanded and young leaves, it took several days to reach pre-stress ABA values. ABA-GE synthesis ceased in the mature leaves, once the stress was relieved, but continued in the half expanded and young leaves for 2 days. Mature leaves, when detached and stressed, accumulated an amount of ABA similar to that in leaves on the intact plant. In contrast, detached and stressed young leaves produced little ABA. Studies with radioactive (+/-)-ABA indicated that in young leaves the conversion of ABA to PA took place at a much lower rate than in mature ones. 25 references, 10 figures, 2 tables.

  17. Identification of Interactions between Abscisic Acid and Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase.

    Marek M Galka

    Full Text Available Abscisic acid ((+-ABA is a phytohormone involved in the modulation of developmental processes and stress responses in plants. A chemical proteomics approach using an ABA mimetic probe was combined with in vitro assays, isothermal titration calorimetry (ITC, x-ray crystallography and in silico modelling to identify putative (+-ABA binding-proteins in crude extracts of Arabidopsis thaliana. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco was identified as a putative ABA-binding protein. Radiolabelled-binding assays yielded a Kd of 47 nM for (+-ABA binding to spinach Rubisco, which was validated by ITC, and found to be similar to reported and experimentally derived values for the native ribulose-1,5-bisphosphate (RuBP substrate. Functionally, (+-ABA caused only weak inhibition of Rubisco catalytic activity (Ki of 2.1 mM, but more potent inhibition of Rubisco activation (Ki of ~ 130 μM. Comparative structural analysis of Rubisco in the presence of (+-ABA with RuBP in the active site revealed only a putative low occupancy (+-ABA binding site on the surface of the large subunit at a location distal from the active site. However, subtle distortions in electron density in the binding pocket and in silico docking support the possibility of a higher affinity (+-ABA binding site in the RuBP binding pocket. Overall we conclude that (+-ABA interacts with Rubisco. While the low occupancy (+-ABA binding site and weak non-competitive inhibition of catalysis may not be relevant, the high affinity site may allow ABA to act as a negative effector of Rubisco activation.

  18. NFX1-LIKE2 (NFXL2 suppresses abscisic acid accumulation and stomatal closure in Arabidopsis thaliana.

    Janina Lisso

    Full Text Available The NFX1-LIKE1 (NFXL1 and NFXL2 genes were identified as regulators of salt stress responses. The NFXL1 protein is a nuclear factor that positively affects adaptation to salt stress. The nfxl1-1 loss-of-function mutant displayed reduced survival rates under salt and high light stress. In contrast, the nfxl2-1 mutant, defective in the NFXL2 gene, and NFXL2-antisense plants exhibited enhanced survival under these conditions. We show here that the loss of NFXL2 function results in abscisic acid (ABA overaccumulation, reduced stomatal conductance, and enhanced survival under drought stress. The nfxl2-1 mutant displayed reduced stomatal aperture under all conditions tested. Fusicoccin treatment, exposition to increasing light intensities, and supply of decreasing CO(2 concentrations demonstrated full opening capacity of nfxl2-1 stomata. Reduced stomatal opening presumably is a consequence of elevated ABA levels. Furthermore, seedling growth, root growth, and stomatal closure were hypersensitive to exogenous ABA. The enhanced ABA responses may contribute to the improved drought stress resistance of the mutant. Three NFXL2 splice variants were cloned and named NFXL2-78, NFXL2-97, and NFXL2-100 according to the molecular weight of the putative proteins. Translational fusions to the green fluorescent protein suggest nuclear localisation of the NFXL2 proteins. Stable expression of the NFXL2-78 splice variant in nfxl2-1 plants largely complemented the mutant phenotype. Our data show that NFXL2 controls ABA levels and suppresses ABA responses. NFXL2 may prevent unnecessary and costly stress adaptation under favourable conditions.

  19. Alleviation of Osmotic Stress Effects by Exogenous Application of Salicylic or Abscisic Acid on Wheat Seedlings

    Katarzyna Cyganek

    2013-06-01

    Full Text Available The aim of the study was to assess the role of salicylic acid (SA and abscisic acid (ABA in osmotic stress tolerance of wheat seedlings. This was accomplished by determining the impact of the acids applied exogenously on seedlings grown under osmotic stress in hydroponics. The investigation was unique in its comprehensiveness, examining changes under osmotic stress and other conditions, and testing a number of parameters simultaneously. In both drought susceptible (SQ1 and drought resistant (CS wheat cultivars, significant physiological and biochemical changes were observed upon the addition of SA (0.05 mM or ABA (0.1 μM to solutions containing half-strength Hoagland medium and PEG 6000 (−0.75 MPa. The most noticeable result of supplementing SA or ABA to the medium (PEG + SA and PEG + ABA was a decrease in the length of leaves and roots in both cultivars. While PEG treatment reduced gas exchange parameters, chlorophyll content in CS, and osmotic potential, and conversely, increased lipid peroxidation, soluble carbohydrates in SQ1, proline content in both cultivars and total antioxidants activity in SQ1, PEG + SA or PEG + ABA did not change the values of these parameters. Furthermore, PEG caused a two-fold increase of endogenous ABA content in SQ1 and a four-fold increase in CS. PEG + ABA increased endogenous ABA only in SQ1, whereas PEG + SA caused a greater increase of ABA content in both cultivars compared to PEG. In PEG-treated plants growing until the harvest, a greater decrease of yield components was observed in SQ1 than in CS. PEG + SA, and particularly PEG + ABA, caused a greater increase of these yield parameters in CS compared to SQ1. In conclusion, SA and ABA ameliorate, particularly in the tolerant wheat cultivar, the harmful effects and after effects of osmotic stress induced by PEG in hydroponics through better osmotic adjustment achieved by an increase in proline and carbohydrate content as well as by an increase in antioxidant

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

    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.

  1. Growth and graviresponsiveness of primary roots of Zea mays seedlings deficient in abscisic acid and gibberellic acid

    Moore, R.; Dickey, K.

    1985-01-01

    The objective of this research was to determine if gibberellic acid (GA) and/or abscisic acid (ABA) are necessary for graviresponsiveness by primary roots of Zea mays. To accomplish this objective we measured the growth and graviresponsiveness of primary roots of seedlings in which the synthesis of ABA and GA was inhibited collectively and individually by genetic and chemical means. Roots of seedlings treated with Fluridone (an inhibitor of ABA biosynthesis) and Ancymidol (an inhibitor of GA biosynthesis) were characterized by slower growth rates but not significantly different gravicultures as compared to untreated controls. Gravicurvatures of primary roots of d-5 mutants (having undetectable levels of GA) and vp-9 mutants (having undectable levels of ABA) were not significantly different from those of wild-type seedlings. Roots of seedlings in which the biosynthesis of ABA and GA was collectively inhibited were characterized by gravicurvatures not significantly different for those of controls. These results (1) indicate that drastic reductions in the amount of ABA and GA in Z. mays seedlings do not significantly alter root graviresponsiveness, (2) suggest that neither ABA nor GA is necessary for root gravicurvature, and (3) indicate that root gravicurvature is not necessarily proportional to root elongation.

  2. H2O2 mediates the crosstalk of brassinosteroid and abscisic acid in tomato responses to heat and oxidative stresses

    Zhou, Jie; Wang, Jian; Li, Xin; Xia, Xiao-Jian; Zhou, Yan-Hong; Shi, Kai; Chen, Zhixiang; Yu, Jing-Quan

    2014-01-01

    The production of H2O2 is critical for brassinosteroid (BR)- and abscisic acid (ABA)-induced stress tolerance in plants. In this study, the relationship between BR and ABA in the induction of H2O2 production and their roles in response to heat and paraquat (PQ) oxidative stresses were studied in tomato. Both BR and ABA induced increases in RBOH1 gene expression, NADPH oxidase activity, apoplastic H2O2 accumulation, and heat and PQ stress tolerance in wild-type plants. BR could only induced tr...

  3. Altered cytokinin metabolism affects cytokinin, auxin, and abscisic acid contents in leaves and chloroplasts, and chloroplast ultrastructure in transgenic tobacco

    Polanská, Lenka; Vičánková, Anna; Nováková, Marie; Malbeck, Jiří; Dobrev, Petre; Brzobohatý, Břetislav; Vaňková, Radomíra; Macháčková, Ivana

    2007-01-01

    Roč. 58, č. 3 (2007), s. 637-649. ISSN 0022-0957 R&D Projects: GA ČR GA206/03/0369; GA ČR GA206/06/1306; GA AV ČR IAA600040612 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50040507 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : abscisic acid * auxin * chloroplast ultrastructure Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  4. Influence of mineral nutrition, ozone, and acid fog on abscisic acid and indole acetic acid in needles of Picea abies (L. ) Karst

    Fackler, U.; Huber, W.; Hock, B.

    1986-09-01

    The phytohormones abscisic acid and auxin (total, free, and alkali-labile IAA) were quantified in needles from spruces which had been exposed to air pollutants under different controlled climatic conditions within the MAGL pilot project. Increased concentrations of ABA were found especially in the most recent needles after ozone treatment. Noticeable changes in auxin concentrations could not be observed. These results should be backed up by further experiments with more samples in order to gain insight into the hormonal balance of plants under stress by air pollution.

  5. Abscisic acid induces biosynthesis of bisbibenzyls and tolerance to UV-C in the liverwort Marchantia polymorpha.

    Kageyama, Akito; Ishizaki, Kimitsune; Kohchi, Takayuki; Matsuura, Hideyuki; Takahashi, Kosaku

    2015-09-01

    Environmental stresses are effective triggers for the biosynthesis of various secondary metabolites in plants, and phytohormones such as jasmonic acid and abscisic acid are known to mediate such responses in flowering plants. However, the detailed mechanism underlying the regulation of secondary metabolism in bryophytes remains unclear. In this study, the induction mechanism of secondary metabolites in the model liverwort Marchantia polymorpha was investigated. Abscisic acid (ABA) and ultraviolet irradiation (UV-C) were found to induce the biosynthesis of isoriccardin C, marchantin C, and riccardin F, which are categorized as bisbibenzyls, characteristic metabolites of liverworts. UV-C led to the significant accumulation of ABA. Overexpression of MpABI1, which encodes protein phosphatase 2C (PP2C) as a negative regulator of ABA signaling, suppressed accumulation of bisbibenzyls in response to ABA and UV-C irradiation and conferred susceptibility to UV-C irradiation. These data show that ABA plays a significant role in the induction of bisbibenzyl biosynthesis, which might confer tolerance against UV-C irradiation in M. polymorpha. PMID:26055979

  6. Arabidopsis cysteine-rich receptor-like kinase 45 functions in the responses to abscisic acid and abiotic stresses

    Zhang, Xiujuan

    2013-06-01

    The phytohormone abscisic acid (ABA) regulates seed germination, plant growth and development, and response to abiotic stresses such as drought and salt stresses. Receptor-like kinases are well known signaling components that mediate plant responses to developmental and environmental stimuli. Here, we characterized the biological function of an ABA and stress-inducible cysteine-rich receptor-like protein kinase, CRK45, in ABA signaling in Arabidopsis thaliana. The crk45 mutant was less sensitive to ABA than the wild type during seed germination and early seedling development, whereas CRK45 overexpression plants were more sensitive to ABA compared to the wild type. Furthermore, overexpression of CRK45 led to hypersensitivity to salt and glucose inhibition of seed germination, whereas the crk45 mutant showed the opposite phenotypes. In addition, CRK45 overexpression plants had enhanced tolerance to drought. Gene expression analyses revealed that the expression of representative stress-responsive genes was significantly enhanced in CRK45 overexpression plants in response to salt stress. ABA biosynthetic genes such as NCED3,. 22NCED3, 9-Cis-Epoxycarotenoid Dioxygenase 3.NCED5,. 33NCED5, 9-Cis-Epoxycarotenoid Dioxygenase 5.ABA2,. 44ABA2, Abscisic Acid Deficient 2. and AAO355AAO3, Abscisic Aldehyde Oxidase 3. were also constitutively elevated in the CRK45 overexpression plants. We concluded that CRK45 plays an important role in ABA signaling that regulates Arabidopsis seeds germination, early seedling development and abiotic stresses response, by positively regulating ABA responses in these processes. © 2013 Elsevier Masson SAS.

  7. QTLs and candidate genes for desiccation and abscisic acid content in maize kernels

    Charcosset Alain

    2010-01-01

    Full Text Available Abstract Background Kernel moisture at harvest is an important trait since a low value is required to prevent unexpected early germination and ensure seed preservation. It is also well known that early germination occurs in viviparous mutants, which are impaired in abscisic acid (ABA biosynthesis. To provide some insight into the genetic determinism of kernel desiccation in maize, quantitative trait loci (QTLs were detected for traits related to kernel moisture and ABA content in both embryo and endosperm during kernel desiccation. In parallel, the expression and mapping of genes involved in kernel desiccation and ABA biosynthesis, were examined to detect candidate genes. Results The use of an intermated recombinant inbred line population allowed for precise QTL mapping. For 29 traits examined in an unreplicated time course trial of days after pollination, a total of 78 QTLs were detected, 43 being related to kernel desiccation, 15 to kernel weight and 20 to ABA content. Multi QTL models explained 35 to 50% of the phenotypic variation for traits related to water status, indicating a large genetic control amenable to breeding. Ten of the 20 loci controlling ABA content colocated with previously detected QTLs controlling water status and ABA content in water stressed leaves. Mapping of candidate genes associated with kernel desiccation and ABA biosynthesis revealed several colocations between genes with putative functions and QTLs. Parallel investigation via RT-PCR experiments showed that the expression patterns of the ABA-responsive Rab17 and Rab28 genes as well as the late embryogenesis abundant Emb5 and aquaporin genes were related to desiccation rate and parental allele effect. Database searches led to the identification and mapping of two zeaxanthin epoxidase (ZEP and five novel 9-cis-epoxycarotenoid dioxygenase (NCED related genes, both gene families being involved in ABA biosynthesis. The expression of these genes appeared independent in

  8. Conclusion on the peer review of the pesticide risk assessment of the active substance S-abscisic acid

    European Food Safety Authority

    2013-08-01

    Full Text Available The conclusions of the European Food Safety Authority (EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State the Netherlands, for the pesticide active substance S-abscisic acid are reported. The context of the peer review was that required by Commission Regulation EU No 188/2011. The conclusions were reached on the basis of the evaluation of the representative uses of S-abscisic acid as a plant growth regulator on tomato seedlings and grapes. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified in the areas of residues and ecotoxicology, as the consumer risk assessment and the risk assessment for higher aquatic plants for some metabolites could not be finalised based on the data available.

  9. Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize

    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.

  10. Up-regulation of abscisic acid signaling pathway facilitates aphid xylem absorption and osmoregulation under drought stress.

    Guo, Huijuan; Sun, Yucheng; Peng, Xinhong; Wang, Qinyang; Harris, Marvin; Ge, Feng

    2016-02-01

    The activation of the abscisic acid (ABA) signaling pathway reduces water loss from plants challenged by drought stress. The effect of drought-induced ABA signaling on the defense and nutrition allocation of plants is largely unknown. We postulated that these changes can affect herbivorous insects. We studied the effects of drought on different feeding stages of pea aphids in the wild-type A17 of Medicago truncatula and ABA signaling pathway mutant sta-1. We examined the impact of drought on plant water status, induced plant defense signaling via the abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) pathways, and on the host nutritional quality in terms of leaf free amino acid content. During the penetration phase of aphid feeding, drought decreased epidermis/mesophyll resistance but increased mesophyll/phloem resistance of A17 but not sta-1 plants. Quantification of transcripts associated with ABA, JA and SA signaling indicated that the drought-induced up-regulation of ABA signaling decreased the SA-dependent defense but increased the JA-dependent defense in A17 plants. During the phloem-feeding phase, drought had little effect on the amino acid concentrations and the associated aphid phloem-feeding parameters in both plant genotypes. In the xylem absorption stage, drought decreased xylem absorption time of aphids in both genotypes because of decreased water potential. Nevertheless, the activation of the ABA signaling pathway increased water-use efficiency of A17 plants by decreasing the stomatal aperture and transpiration rate. In contrast, the water potential of sta-1 plants (unable to close stomata) was too low to support xylem absorption activity of aphids; the aphids on sta-1 plants had the highest hemolymph osmolarity and lowest abundance under drought conditions. Taken together this study illustrates the significance of cross-talk between biotic-abiotic signaling pathways in plant-aphid interaction, and reveals the mechanisms leading to alter

  11. Chemical ionization mass spectrometry of indol-3yl-acetic acid and cis-abscisic acid: evaluation of negative ion detection and quantification of cis-abscisic acid in growing maize roots

    Mass spectra of the derivatives of indol-3yl-acetic acid and cis-abscisic acid were obtained in electron impact and chemical ionization positive ion and negative ion modes. The respective merits of methane, isobutane, and ammonia as reagent gases for structure determination and sensitive detection were compared using the methyl esters. From one to 10 fluorine atoms were attached to IAA to improve the electron-capturing properties of the molecule. The best qualitative information was obtained when using positive ion chemical ionization with methane. However, the most sensitive detection, with at least two ions per molecule, was achieved by electron impact on the IAA-HFB-ME derivative and by negative ion chemical ionization with NH3 on the ABA-methyl ester derivative. p ]Quantitative analyses of ABA in different parts of maize (Zea mays cv. LG 11) root tips were performed by the latter technique. It was found that the cap and apex contained less ABA than the physiologically older parts of the root such as the elongation zone and the more differentiated tissues. This technique was also used to show a relation between maize root growth and the endogenous ABA level of the elongation zone and root tip: there is more ABA in the slowly growing roots than in the rapidly growing ones. (author)

  12. Reduced de-etiolation of hypocotyl growth in a tomato mutant is associated with hypersensitivity to, and high endogenous levels of, abscisic acid

    Fellner, Martin; Zhang, R.; Pharis, R.; Sawhney, V.

    2001-01-01

    Roč. 52, č. 357 (2001), s. 725-738. ISSN 0022-0957 R&D Projects: GA ČR GV521/96/K117 Institutional research plan: CEZ:AV0Z5038910 Keywords : Abscisic acid * elongated mutant * fluridone Subject RIV: EF - Botanics Impact factor: 2.433, year: 2001

  13. Fast and efficient separation of cytokinins from auxin and abscisic acid and their purification using mixed-mode solid-phase extraction

    Dobrev, Petre; Kamínek, Miroslav

    2002-01-01

    Roč. 950, č. 1 (2002), s. 21-29. ISSN 0021-9673 R&D Projects: GA ČR GA206/02/0967; GA ČR GA522/02/0530 Institutional research plan: CEZ:AV0Z5038910 Keywords : cytokinins * abscisic acid * extraction Subject RIV: EF - Botanics Impact factor: 3.098, year: 2002

  14. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth.

    Castellarin, Simone D; Gambetta, Gregory A; Wada, Hiroshi; Krasnow, Mark N; Cramer, Grant R; Peterlunger, Enrico; Shackel, Kenneth A; Matthews, Mark A

    2016-02-01

    Along with sugar accumulation and colour development, softening is an important physiological change during the onset of ripening in fruits. In this work, we investigated the relationships among major events during softening in grape (Vitis vinifera L.) by quantifying elasticity in individual berries. In addition, we delayed softening and inhibited sugar accumulation using a mechanical growth-preventing treatment in order to identify processes that are sugar and/or growth dependent. Ripening processes commenced on various days after anthesis, but always at similarly low elasticity and turgor. Much of the softening occurred in the absence of other changes in berry physiology investigated here. Several genes encoding key cell wall-modifying enzymes were not up-regulated until softening was largely completed, suggesting softening may result primarily from decreases in turgor. Similarly, there was no decrease in solute potential, increase in sugar concentration, or colour development until elasticity and turgor were near minimum values, and these processes were inhibited when berry growth was prevented. Increases in abscisic acid occurred early during softening and in the absence of significant expression of the V. vinifera 9-cis-epoxycarotenoid dioxygenases. However, these increases were coincident with decreases in the abscisic acid catabolite diphasic acid, indicating that initial increases in abscisic acid may result from decreases in catabolism and/or exogenous import. These data suggest that softening, decreases in turgor, and increases in abscisic acid represent some of the earliest events during the onset of ripening. Later, physical growth, further increases in abscisic acid, and the accumulation of sugar are integral for colour development. PMID:26590311

  15. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid W

    Messing, S.; Gabelli, S; Echeverria, I; Vogel, J; Guan, J; Tan, B; Klee, H; McCarty, D; Amzela, M

    2010-01-01

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  16. Effects of Formulated Fertilizer Synergist on Abscisic Acid Accumulation, Proline Content and Photosynthetic Characteristics of Rice under Drought

    WANG Shao-xian; XIA Shi-tou; PENG Ke-qin; KUANG Feng-chun; CAO Yong; XIAO Lang-tao

    2007-01-01

    To investigate the effects of formulated fertilizer synergist on the drought tolerance in rice, pot experiment was conducted to analyze the photosynthetic characteristics and the accumulation of abscisic acid (ABA) and proline in middle-season rice variety Peiliangyou 93. The synergist could improve the net photosynthetic rate, and coordination between the water loss and the CO2 absorption as well as reduce the harmful effect on photosynthetic process under drought conditions. Under drought, the ABA accumulated massively both in roots and leaves, while the ABA content in roots was far higher than that in leaves. The results indicate that synergist could increase the ABA accumulation, but reduce the proline accumulation in rice plant under drought.

  17. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid

    Messing, Simon A.J.; Gabelli, Sandra B.; Echeverria, Ignacia; Vogel, Jonathan T.; Guan, Jiahn Chou; Tan, Bao Cai; Klee, Harry J.; McCarty, Donald R.; Amzel, L. Mario (JHU); (Florida)

    2011-09-06

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  18. A GH3 family member, OsGH3-2, modulates auxin and abscisic acid levels and differentially affects drought and cold tolerance in rice

    Du, Hao; Wu, Nai; Fu, Jing; Wang, Shiping; Li, Xianghua; Xiao, Jinghua; Xiong, Lizhong

    2012-01-01

    Plant responses to abiotic stresses are coordinated by arrays of growth and developmental processes. Indole-3-acetic acid (IAA) and abscisic acid (ABA) play critical roles in developmental programmes and environmental responses, respectively, through complex signalling and metabolism networks. However, crosstalk between the two phytohormones in the stress responses remains largely unknown. Here, it is reported that a GH3 family gene, OsGH3-2, encoding an enzyme catalysing IAA conjugation to a...

  19. Separation of Abscisic Acid, Indole-3-Acetic Acid, Gibberellic Acid in 99 R (Vitis berlandieri x Vitis rupestris) and Rose Oil (Rosa damascena Mill.) by Reversed Phase Liquid Chromatography

    KELEN, Mustafa

    2004-01-01

    Plant hormones, specialized chemical substances produced by plants, are the main internal factors controlling growth and development. In this study the pH and polarity of the mobile phase were taken into consideration to optimize the mobile phase for the chromatographic separation of 3 important plant hormones: abscisic acid (ABA), indole-3-acetic acid (IAA) and gibberellic acid (GA3). pKa values of ABA, IAA and GA3 were determined using retention factors. These 3 hormones were extr...

  20. Influence of abscisic acid on growth, biomass and lipid yield of Scenedesmus quadricauda under nitrogen starved condition.

    Sulochana, Sujitha Balakrishnan; Arumugam, Muthu

    2016-08-01

    Scenedesmus quadricauda, accumulated more lipid but with a drastic reduction in biomass yield during nitrogen starvation. Abscisic acid (ABA) being a stress responsible hormone, its effect on growth and biomass with sustainable lipid yield during nitrogen depletion was studied. The result revealed that the ABA level shoots up at 24h (27.21pmol/L) during the onset of nitrogen starvation followed by a sharp decline. The external supplemented ABA showed a positive effect on growth pattern (38×10(6)cells/ml) at a lower concentration. The dry biomass yield is also increasing up to 2.1 fold compared to nitrogen deficient S. quadricauda. The lipid content sustains in 1 and 2μM concentration of ABA under nitrogen-deficient condition. The fatty acid composition of ABA treated S. quadricauda cultures with respect to nitrogen-starved cells showed 11.17% increment in saturated fatty acid content, the desired lipid composition for biofuel application. PMID:26949054

  1. Kinetic Characterisation of a Single Chain Antibody against the Hormone Abscisic Acid: Comparison with Its Parental Monoclonal

    Badescu, George O.; Marsh, Andrew; Smith, Timothy R.; Thompson, Andrew J.; Napier, Richard M.

    2016-01-01

    A single-chain Fv fragment antibody (scFv) specific for the plant hormone abscisic acid (ABA) has been expressed in the bacterium Escherichia coli as a fusion protein. The kinetics of ABA binding have been measured using surface plasmon resonance spectrometry (BIAcore 2000) using surface and solution assays. Care was taken to calculate the concentration of active protein in each sample using initial rate measurements under conditions of partial mass transport limitation. The fusion product, parental monoclonal antibody and the free scFv all have low nanomolar affinity constants, but there is a lower dissociation rate constant for the parental monoclonal resulting in a three-fold greater affinity. Analogue specificity was tested and structure-activity binding preferences measured. The biologically-active (+)-ABA enantiomer is recognised with an affinity three orders of magnitude higher than the inactive (-)-ABA. Metabolites of ABA including phaseic acid, dihydrophaseic acid and deoxy-ABA have affinities over 100-fold lower than that for (+)-ABA. These properties of the scFv make it suitable as a sensor domain in bioreporters specific for the naturally occurring form of ABA. PMID:27023768

  2. Effects of Exterior Abscisic Acid on Calcium Distribution of Mesophyll Cells and Calcium Concentration of Guard Cells in Maize Seedlings

    GUO Xiu-lin; MA Yuan-yuan; LIU Zi-hui; LIU Bin-hui

    2008-01-01

    In this study, the direct effects of exterior abscisic acid (ABA) on both calcium distribution of mesophyll cells and cytosolic calcium concentration of guard cells were examined. The distribution of Ca2+ localization were observed with calcium antimonate precipitate-electromicroscopic-cyto-chemical methods after treated with ABA and pretreated with ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), verapamil (Vp), and trifluoperazine (TFP). The laser scanning confocal microscopy was used to measure the cytosolic calcium concentrations of guard cells under different treatments. The results showed that the cytosolic Ca2+ concentration of mesophyll cells was induced to increase by ABA, but to decrease in both outside cell and the vacuoles within 10 min after treatments. The cytosolic calcium concentration of guard cells was increased gradually with the lag in treatment time. However, both EGTA and TFP could inverse those effects, indicating that the increase of cytosolic calcium induced by exterior ABA was mainly caused by calcium influx. The results also showed that calmodulin could influence both the calcium distribution of mesophyll cells and calcium concentration of guard cells. It shows that calmodulin participates in the process of ABA signal transduction, but the mechanism is not known as yet. The changes both calcium distribution of mesophyll cells and calcium concentration of guard cells further proved that the variations of cytosolic Ca2+ concentration induced by ABA were involved in the stomatal movements of maize seedlings.

  3. Abscisic acid content, transpiration, and stomatal conductance as related to leaf age in plants Xanthium strumarium L

    Raschke, K.; Zeevaart, J.A.D.

    1976-01-01

    Among the four uppermost leaves of greenhouse-grown plants of Xanthium strumarium L., the content of abscisic acid per unit fresh or dry weight was highest in the youngest leaf and decreased gradually with increasing age of the leaves. Expressed per leaf, the second youngest leaf was richest in ABA; the amount of ABA per leaf declined only slightly as the leaves expanded. Transpiration and stomatal conductance were negatively correlated with the ABA concentration in the leaves; the youngest leaf lost the least amount of water. This correlation was always very good if the youngest leaf was compared with the older leaves but not always good among the older leaves. Since stomatal sensitivity to exogenous (+-)-ABA was the same in leaves of all four age groups ABA may be in at least two compartments in the leaf, one of which is isolated from the guard cells. The ability to synthesize ABA in response to wilting or chilling was strongly expressed in young leaves and declined with leaf age. There was no difference between leaves in their content of the metabolites of ABA, phaseic, and dihydrophaseic acid, expressed per unit weight.

  4. Abscisic Acid and Cytokinin-Induced Osmotic and Antioxidant Regulation in Two Drought-Tolerant and Drought-Sensitive Cultivars of Wheat During Grain Filling Under Water Deficit in Field Conditions

    Mohammad-Reza SARAFRAZ-ARDAKANI

    2014-09-01

    Full Text Available Phytohormones play critical roles in regulating plant responses to stress. The present study investigates the effect of cytokinin, abscisic acid and cytokinin/abscisic acid interaction on some osmoprotectants and antioxidant parameters induced by drought stress in two wheat cultivars (Triticum aestivum L. of ‘Pishgam’ and ‘MV-17’ as tolerant and sensitive to drought during post-anthesis phase, respectively grown in field conditions. The most considerable effect of the treatments was exhibited 21 days after anthesis. Under drought conditions, the flag leaf soluble carbohydrate content increased in both cultivars while starch content was remarkably decreased in ‘Pishgam’ as compared to ‘MV-17’. Abscisic acid increased total soluble sugar and reduced starch more than other hormonal treatments, although it decreased studied monosaccharaides in ‘Pishgam’, especially. Drought stress induced high proportion of gylycinebetain and free proline in ‘Pishgam’ cultivar. Application of abscisic acid and cytokinin/abscisic acid interaction increased gylycinebetain and proline content in both cultivars under irrigation and drought conditions. The tolerant cultivar exhibited less accumulation of hydrogen peroxide and malondialdehyde in relation to significant increase of catalase and peroxidase activities and α-tocpherol content under drought conditions. All hormonal treatments increased the named enzyme activities under both irrigation and drought conditions, while higher accumulation of α-tocopherol was only showed in case of cytokinin application. Also, abscisic acid and cytokinin/abscisic acid could decrease drought-induced hydrogen peroxide and malondialdehyde level to some extent, although abscisic acid increased both of hydrogen peroxide andmalondialdehyde content in irrigation phase, especially.

  5. Abscisic Acid and Cytokinin-Induced Osmotic and Antioxidant Regulation in Two Drought-Tolerant and Drought-Sensitive Cultivars of Wheat During Grain Filling Under Water Deficit in Field Conditions

    2014-01-01

    Phytohormones play critical roles in regulating plant responses to stress. The present study investigates the effect of cytokinin, abscisic acid and cytokinin/abscisic acid interaction on some osmoprotectants and antioxidant parameters induced by drought stress in two wheat cultivars (Triticum aestivum L.) of ‘Pishgam’ and ‘MV-17’ as tolerant and sensitive to drought during post-anthesis phase, respectively grown in field conditions. The most considerable effect of the treatments was exhibite...

  6. Plant, cell, and molecular mechanisms of abscisic-acid regulation of stomatal apertures. In vivo phosphorylation of phosphoenolpyruvate carboxylase in guard cells of Vicia faba L. is enhanced by fusicoccin and suppressed by abscisic acid

    Du, Z.; Aghoram, K.; Outlaw, W.H. Jr.

    1996-12-31

    Plants regulate water loss and CO{sub 2} gain by modulating the aperture sizes of stomata that penetrate the epidermis. Aperture size itself is increased by osmolyte accumulation and consequent turgor increase in the pair of guard cells that flank each stoma. Guard-cell phosphoenolpyruvate carboxylase, which catalyzes the regulated step leading to malate synthesis, is crucial for charge and pH maintenance during osmolyte accumulation. Regulation of this cytosolic enzyme by effectors is well documented, but additional regulation by posttranslational modification is predicted by the alteration of PEPC kinetics during stomatal opening. In this study, the authors have investigated whether this alteration is associated with the phosphorylation status of this enzyme. Using sonicated epidermal peels (isolated guard cells) pre-loaded with {sub 32}PO{sub 4}, the authors induced stomatal opening and guard-cell malate accumulation by incubation with 5 {micro}M fusicoccin (FC). In corroboratory experiments, guard cells were incubated with 5 {micro}M fusicoccin (FC). In corroboratory experiments, guard cells were incubated with the FC antagonist, 10 {micro}M abscisic acid (ABA). The phosphorylation status of PEPC was assessed by immunoprecipitation, electrophoresis, immunoblotting, and autoradiography. PEPC was phosphorylated when stomata were stimulated to open, and phosphorylation was lessened by incubation with ABA.

  7. Antagonistic roles of abscisic acid and cytokinin during response to nitrogen depletion in oleaginous microalga Nannochloropsis oceanica expand the evolutionary breadth of phytohormone function

    Lu, Y.; Tarkowská, Danuše; Turečková, Veronika; Luo, T.; Xin, Y.; Li, J.; Wang, Q.; Jiao, N.; Strnad, Miroslav; Xu, J.

    2014-01-01

    Roč. 80, č. 1 (2014), s. 52-68. ISSN 0960-7412 R&D Projects: GA ČR GA206/09/1284; GA MŠk LK21306; GA MŠk(CZ) LO1204 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Nannochloropsis oceanica * antagonistic synergy * abscisic acid Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.972, year: 2014

  8. ASCORBATE PEROXIDASE6 protects Arabidopsis desiccating and germinating seeds from stress and mediates cross talk between reactive oxygen species, abscisic acid, and auxin

    Chen, Ch.; Letnik, I.; Hacham, Y.; Dobrev, Petre; Ben-Daniel, B.H.; Vaňková, Radomíra; Amir, R.; Miller, G.

    2014-01-01

    Roč. 166, č. 1 (2014), s. 370-383. ISSN 0032-0889 R&D Projects: GA ČR GA206/09/2062 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * abscisic acid * germinating seeds Subject RIV: ED - Physiology Impact factor: 6.841, year: 2014 http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=MEDLINE&DestLinkType=FullRecord&UT=25049361

  9. Major latex protein-like protein 43 (MLP43) functions as a positive regulator during abscisic acid responses and confers drought tolerance in Arabidopsis thaliana

    WANG, YANPING; Yang, Li; Chen, Xi; Ye, Tiantian; Zhong, Bao; Liu, Ruijie; Wu, Yan; Chan, Zhulong

    2015-01-01

    Drought stress is one of the disadvantageous environmental conditions for plant growth and reproduction. Given the importance of abscisic acid (ABA) to plant growth and abiotic stress responses, identification of novel components involved in ABA signalling transduction is critical. In this study, we screened numerous Arabidopsis thaliana mutants by seed germination assay and identified a mutant mlp43 (major latex protein-like 43) with decreased ABA sensitivity in seed germination. The mlp43 m...

  10. Comparative Transcriptome Analysis Reveals the Influence of Abscisic Acid on the Metabolism of Pigments, Ascorbic Acid and Folic Acid during Strawberry Fruit Ripening.

    Dongdong Li

    Full Text Available A comprehensive investigation of abscisic acid (ABA biosynthesis and its influence on other important phytochemicals is critical for understanding the versatile roles that ABA plays during strawberry fruit ripening. Using RNA-seq technology, we sampled strawberry fruit in response to ABA or nordihydroguaiaretic acid (NDGA; an ABA biosynthesis blocker treatment during ripening and assessed the expression changes of genes involved in the metabolism of pigments, ascorbic acid (AsA and folic acid in the receptacles. The transcriptome analysis identified a lot of genes differentially expressed in response to ABA or NDGA treatment. In particular, genes in the anthocyanin biosynthesis pathway were actively regulated by ABA, with the exception of the gene encoding cinnamate 4-hydroxylase. Chlorophyll degradation was accelerated by ABA mainly owing to the higher expression of gene encoding pheide a oxygenase. The decrease of β-carotene content was accelerated by ABA treatment and delayed by NDGA. A high negative correlation rate was found between ABA and β-carotene content, indicating the importance of the requirement for ABA synthesis during fruit ripening. In addition, evaluation on the folate biosynthetic pathway indicate that ABA might have minor function in this nutrient's biosynthesis process, however, it might be involved in its homeostasis. Surprisingly, though AsA content accumulated during fruit ripening, expressions of genes involved in its biosynthesis in the receptacles were significantly lower in ABA-treated fruits. This transcriptome analysis expands our understanding of ABA's role in phytochemical metabolism during strawberry fruit ripening and the regulatory mechanisms of ABA on these pathways were discussed. Our study provides a wealth of genetic information in the metabolism pathways and may be helpful for molecular manipulation in the future.

  11. Interaction between abscisic acid and nitric oxide in PB90-induced catharanthine biosynthesis of catharanthus roseus cell suspension cultures.

    Chen, Qian; Chen, Zunwei; Lu, Li; Jin, Haihong; Sun, Lina; Yu, Qin; Xu, Hongke; Yang, Fengxia; Fu, Mengna; Li, Shengchao; Wang, Huizhong; Xu, Maojun

    2013-01-01

    Elicitations are considered to be an important strategy to improve production of secondary metabolites of plant cell cultures. However, mechanisms responsible for the elicitor-induced production of secondary metabolites of plant cells have not yet been fully elucidated. Here, we report that treatment of Catharanthus roseus cell suspension cultures with PB90, a protein elicitor from Phytophthora boehmeriae, induced rapid increases of abscisic acid (ABA) and nitric oxide (NO), subsequently followed by the enhancement of catharanthine production and up-regulation of Str and Tdc, two important genes in catharanthine biosynthesis. PB90-induced catharanthine production and the gene expression were suppressed by the ABA inhibitor and NO scavenger respectively, showing that ABA and NO are essential for the elicitor-induced catharanthine biosynthesis. The relationship between ABA and NO in mediating catharanthine biosynthesis was further investigated. Treatment of the cells with ABA triggered NO accumulation and induced catharanthine production and up-regulation of Str and Tdc. ABA-induced catharanthine production and gene expressions were suppressed by the NO scavenger. Conversely, exogenous application of NO did not stimulate ABA generation and treatment with ABA inhibitor did not suppress NO-induced catharanthine production and gene expressions. Together, the results showed that both NO and ABA were involved in PB90-induced catharanthine biosynthesis of C. roseus cells. Furthermore, our data demonstrated that ABA acted upstream of NO in the signaling cascade leading to PB90-induced catharanthine biosynthesis of C. roseus cells. PMID:23554409

  12. Characterization of the 9-cis-epoxycarotenoid dioxygenase gene family and the regulation of abscisic acid biosynthesis in avocado.

    Chernys, J T; Zeevaart, J A

    2000-09-01

    Avocado (Persea americana Mill. cv Lula) is a climacteric fruit that exhibits a rise in ethylene as the fruit ripens. This rise in ethylene is followed by an increase in abscisic acid (ABA), with the highest level occurring just after the peak in ethylene production. ABA is synthesized from the cleavage of carotenoid precursors. The cleavage of carotenoid precursors produces xanthoxin, which can subsequently be converted into ABA via ABA-aldehyde. Indirect evidence indicates that the cleavage reaction, catalyzed by 9-cis-epoxycarotenoid dioxygenase (NCED), is the regulatory step in ABA synthesis. Three genes encoding NCED cleavage-like enzymes were cloned from avocado fruit. Two genes, PaNCED1 and PaNCED3, were strongly induced as the fruit ripened. The other gene, PaNCED2, was constitutively expressed during fruit ripening, as well as in leaves. This gene lacks a predicted chloroplast transit peptide. It is therefore unlikely to be involved in ABA biosynthesis. PaNCED1 was induced by water stress, but expression of PaNCED3 was not detectable in dehydrated leaves. Recombinant PaNCED1 and PaNCED3 were capable of in vitro cleavage of 9-cis-xanthophylls into xanthoxin and C(25)-apocarotenoids, but PaNCED2 was not. Taken together, the results indicate that ABA biosynthesis in avocado is regulated at the level of carotenoid cleavage. PMID:10982448

  13. Endogenous abscisic acid promotes hypocotyl growth and affects endoreduplication during dark-induced growth in tomato (Solanum lycopersicum L..

    Jan F Humplík

    Full Text Available Dark-induced growth (skotomorphogenesis is primarily characterized by rapid elongation of the hypocotyl. We have studied the role of abscisic acid (ABA during the development of young tomato (Solanum lycopersicum L. seedlings. We observed that ABA deficiency caused a reduction in hypocotyl growth at the level of cell elongation and that the growth in ABA-deficient plants could be improved by treatment with exogenous ABA, through which the plants show a concentration dependent response. In addition, ABA accumulated in dark-grown tomato seedlings that grew rapidly, whereas seedlings grown under blue light exhibited low growth rates and accumulated less ABA. We demonstrated that ABA promotes DNA endoreduplication by enhancing the expression of the genes encoding inhibitors of cyclin-dependent kinases SlKRP1 and SlKRP3 and by reducing cytokinin levels. These data were supported by the expression analysis of the genes which encode enzymes involved in ABA and CK metabolism. Our results show that ABA is essential for the process of hypocotyl elongation and that appropriate control of the endogenous level of ABA is required in order to drive the growth of etiolated seedlings.

  14. Meristem maintenance, auxin, jasmonic and abscisic acid pathways as a mechanism for phenotypic plasticity in Antirrhinum majus.

    Weiss, Julia; Alcantud-Rodriguez, Raquel; Toksöz, Tugba; Egea-Cortines, Marcos

    2016-01-01

    Plants grow under climatic changing conditions that cause modifications in vegetative and reproductive development. The degree of changes in organ development i.e. its phenotypic plasticity seems to be determined by the organ identity and the type of environmental cue. We used intraspecific competition and found that Antirrhinum majus behaves as a decoupled species for lateral organ size and number. Crowding causes decreases in leaf size and increased leaf number whereas floral size is robust and floral number is reduced. Genes involved in shoot apical meristem maintenance like ROA and HIRZ, cell cycle (CYCD3a; CYCD3b, HISTONE H4) or organ polarity (GRAM) were not significantly downregulated under crowding conditions. A transcriptomic analysis of inflorescence meristems showed Gene Ontology enriched pathways upregulated including Jasmonic and Abscisic acid synthesis and or signalling. Genes involved in auxin synthesis such as AmTAR2 and signalling AmANT were not affected by crowding. In contrast, AmJAZ1, AmMYB21, AmOPCL1 and AmABA2 were significantly upregulated. Our work provides a mechanistic working hypothesis where a robust SAM and stable auxin signalling enables a homogeneous floral size while changes in JA and ABA signalling maybe responsible for the decreased leaf size and floral number. PMID:26804132

  15. Implication of abscisic acid on ripening and quality in sweet cherries: differential effects during pre- and postharvest

    Verónica eTijero

    2016-05-01

    Full Text Available Sweet cherry, a non-climacteric fruit, is usually cold-stored during postharvest to prevent over-ripening. The aim of the study was to evaluate the role of abscisic acid (ABA on fruit growth and ripening of this fruit, considering as well its putative implication in over-ripening and effects on quality. We measured the endogenous concentrations of ABA during the ripening of sweet cherries (Prunus avium L. var. Prime Giant collected from orchard trees and in cherries exposed to 4ºC and 23ºC during 10d of postharvest. Furthermore, we examined to what extent endogenous ABA concentrations were related to quality parameters, such as fruit biomass, anthocyanin accumulation and levels of vitamins C and E. Endogenous concentrations of ABA in fruits increased progressively during fruit growth and ripening on the tree, to decrease later during postharvest at 23ºC. Cold treatment, however, increased ABA levels and led to an inhibition of over-ripening. Furthermore, ABA levels positively correlated with anthocyanin and vitamin E levels during preharvest, but not during postharvest. We conclude that ABA plays a major role in sweet cherry development, stimulating its ripening process and positively influencing quality parameters during preharvest. The possible influence of ABA preventing over-ripening in cold-stored sweet cherries is also discussed.

  16. Implication of Abscisic Acid on Ripening and Quality in Sweet Cherries: Differential Effects during Pre- and Post-harvest.

    Tijero, Verónica; Teribia, Natalia; Muñoz, Paula; Munné-Bosch, Sergi

    2016-01-01

    Sweet cherry, a non-climacteric fruit, is usually cold-stored during post-harvest to prevent over-ripening. The aim of the study was to evaluate the role of abscisic acid (ABA) on fruit growth and ripening of this fruit, considering as well its putative implication in over-ripening and effects on quality. We measured the endogenous concentrations of ABA during the ripening of sweet cherries (Prunus avium L. var. Prime Giant) collected from orchard trees and in cherries exposed to 4°C and 23°C during 10 days of post-harvest. Furthermore, we examined to what extent endogenous ABA concentrations were related to quality parameters, such as fruit biomass, anthocyanin accumulation and levels of vitamins C and E. Endogenous concentrations of ABA in fruits increased progressively during fruit growth and ripening on the tree, to decrease later during post-harvest at 23°C. Cold treatment, however, increased ABA levels and led to an inhibition of over-ripening. Furthermore, ABA levels positively correlated with anthocyanin and vitamin E levels during pre-harvest, but not during post-harvest. We conclude that ABA plays a major role in sweet cherry development, stimulating its ripening process and positively influencing quality parameters during pre-harvest. The possible influence of ABA preventing over-ripening in cold-stored sweet cherries is also discussed. PMID:27200070

  17. Graviresponsiveness and abscisic-acid content of roots of carotenoid-deficient mutants of Zea mays L

    Moore, R.; Smith, J. D.

    1985-01-01

    The abscisic-acid (ABA) content of roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays was analyzed using gas chromatography-mass spectrometry with an analysis sensitivity of 6 ng ABA g-1 fresh weight (FW). Roots of normal seedlings of the same lines were characterized by the following amounts of ABA (as ng ABA g-1 FW, +/- standard deviation): w-3, 279 +/- 43; vp-5, 237 +/- 26; vp-7, 338 +/- 61. We did not detect any ABA in roots of any of the mutants. Thus, the lack of carotenoids in these mutants correlated positively with the apparent absence of ABA. Primary roots of normal and mutant seedlings were positively gravitropic, with no significant differences in the curvatures of roots of normal as compared with mutant seedlings. These results indicate that ABA 1) is synthesized in maize roots via the carotenoid pathway, and 2) is not necessary for positive gravitropism by primary roots of Z. mays.

  18. Genetic interaction of two abscisic acid signaling regulators, HY5 and FIERY1, in mediating lateral root formation

    Chen, Hao

    2011-01-01

    Root architecture is continuously shaped in a manner that helps plants to better adapt to the environment. Gene regulation at the transcriptional or post-transcriptional levels largely controls this environmental response. Recently, RNA silencing has emerged as an important player in gene regulation and is involved in many aspects of plant development, including lateral root formation. In a recent study, we found that FIERY1, a bifunctional abiotic stress and abscisic acid (ABA) signaling regulator and an endogenous RNA silencing suppressor, mediates auxin response during lateral root formation in Arabidopsis. We proposed that FRY1 regulates lateral root development through its activity on adenosine 3,5-bisphosphate (PAP), a strong inhibitor of exoribonucleases (XRNs). Interestingly, some of the phenotypes of fry1, such as enhanced response to light in repressing hypocotyl elongation and hypersensitivity to ABA in lateral root growth, are opposite to those of another light- and ABA-signaling mutant, hy5. Here we analyzed the hy5 fry1 double mutant for root and hypocotyl growth. We found that the hy5 mutation can suppress the enhanced light sensitivity in fry1 hypocotyl elongation and restore the lateral root formation. The genetic interaction between HY5 and FRY1 indicates that HY5 and FRY1 may act in overlapping pathways that mediate light signaling and lateral root development. © 2011 Landes Bioscience.

  19. Abscisic acid regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin.

    Rowe, James H; Topping, Jennifer F; Liu, Junli; Lindsey, Keith

    2016-07-01

    Understanding the mechanisms regulating root development under drought conditions is an important question for plant biology and world agriculture. We examine the effect of osmotic stress on abscisic acid (ABA), cytokinin and ethylene responses and how they mediate auxin transport, distribution and root growth through effects on PIN proteins. We integrate experimental data to construct hormonal crosstalk networks to formulate a systems view of root growth regulation by multiple hormones. Experimental analysis shows: that ABA-dependent and ABA-independent stress responses increase under osmotic stress, but cytokinin responses are only slightly reduced; inhibition of root growth under osmotic stress does not require ethylene signalling, but auxin can rescue root growth and meristem size; osmotic stress modulates auxin transporter levels and localization, reducing root auxin concentrations; PIN1 levels are reduced under stress in an ABA-dependent manner, overriding ethylene effects; and the interplay among ABA, ethylene, cytokinin and auxin is tissue-specific, as evidenced by differential responses of PIN1 and PIN2 to osmotic stress. Combining experimental analysis with network construction reveals that ABA regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin. PMID:26889752

  20. Gene Overexpression and RNA Silencing Tools for the Genetic Manipulation of the S-(+-Abscisic Acid Producing Ascomycete Botrytis cinerea

    Zhong-Tao Ding

    2015-05-01

    Full Text Available The phytopathogenic ascomycete Botrytis cinerea produces several secondary metabolites that have biotechnical significance and has been particularly used for S-(+-abscisic acid production at the industrial scale. To manipulate the expression levels of specific secondary metabolite biosynthetic genes of B. cinerea with Agrobacterium tumefaciens-mediated transformation system, two expression vectors (pCBh1 and pCBg1 with different selection markers and one RNA silencing vector, pCBSilent1, were developed with the In-Fusion assembly method. Both expression vectors were highly effective in constitutively expressing eGFP, and pCBSilent1 effectively silenced the eGFP gene in B. cinerea. Bcaba4, a gene suggested to participate in ABA biosynthesis in B. cinerea, was then targeted for gene overexpression and RNA silencing with these reverse genetic tools. The overexpression of bcaba4 dramatically induced ABA formation in the B. cinerea wild type strain Bc-6, and the gene silencing of bcaba4 significantly reduced ABA-production in an ABA-producing B. cinerea strain.

  1. The parasitic plant Cuscuta australis is highly insensitive to abscisic acid-induced suppression of hypocotyl elongation and seed germination.

    Li, Juan; Hettenhausen, Christian; Sun, Guiling; Zhuang, Huifu; Li, Jian-Hong; Wu, Jianqiang

    2015-01-01

    Around 1% of angiosperms are parasitic plants. Their growth and development solely or partly depend on host plants from which they extract water, nutrients, and other molecules using a parasitic plant-specific organ, the haustorium. Strong depletion of nutrients can result in serious growth retardation and in some cases, death of the hosts. The genus Cuscuta (dodder) comprises about 200 holoparasitic species occurring on all continents. Their seedlings have no roots and cotyledons but are only string-like hypocotyls. When they contact suitable host plants, haustoria are formed and thereafter seedlings rapidly develop into vigorously growing branches without roots and leaves. This highly specialized lifestyle suggests that Cuscuta plants likely have unique physiology in development and stress responses. Using germination and seedling growth assays, we show that C. australis seeds and seedlings are highly insensitive to abscisic acid (ABA). Transcriptome analysis and protein sequence alignment with Arabidopsis, tomato, and rice homologs revealed that C. australis most likely consists of only four functional ABA receptors. Given that Cuscuta plants are no longer severely challenged by drought stress, we hypothesize that the ABA-mediated drought resistance pathway in Cuscuta spp. might have had degenerated over time during evolution. PMID:26258814

  2. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  3. Abscisic acid and ethylene in mutants of Arabidopsis thaliana differing in their resistance to ultraviolet (UV-B) radiation stress

    The effects of ultraviolet irradiation (between 280 and 320 nm) on plant survival, ethylene evolution, and abscisic acid (ABA) content were studied in Arabidopsis thaliana (L.) Heunh. plants. Three genetic lines of Arabidopsis differing in their resistance to ultraviolet (UV-B) radiation stress were used. UV-B irradiation had detrimental effects on plant survival, enhanced ethylene evolution, and increased ABA content in the plants of all three lines. The higher ultraviolet dose was absorbed, the less was the number of surviving plants and the higher were the levels of both phytohormones. The maximum ethylene evolution occurred during the initial two to four hours after irradiation, but the ABA content peaked only after 24 h. The most resistant line showed the highest ABA content and the fastest ethylene evolution, whereas, in the susceptible line, both indices were the lowest. After UV-B treatment, the ABA-deficient Arabidopsis mutant evolved four to six times more ethylene than the plants with normal ABA content. Stress ethylene production evidently did not depend on the level of endogenous ABA as the kinetics of ethylene evolution was similar in the ABA-deficient mutant and in other studied Arabidopsis lines

  4. Genetic analyses of interactions among gibberellin, abscisic acid, and brassinosteroids in the control of flowering time in Arabidopsis thaliana.

    Malgorzata A Domagalska

    Full Text Available BACKGROUND: Genetic interactions between phytohormones in the control of flowering time in Arabidopsis thaliana have not been extensively studied. Three phytohormones have been individually connected to the floral-timing program. The inductive function of gibberellins (GAs is the most documented. Abscisic acid (ABA has been demonstrated to delay flowering. Finally, the promotive role of brassinosteroids (BRs has been established. It has been reported that for many physiological processes, hormone pathways interact to ensure an appropriate biological response. METHODOLOGY: We tested possible genetic interactions between GA-, ABA-, and BR-dependent pathways in the control of the transition to flowering. For this, single and double mutants deficient in the biosynthesis of GAs, ABA, and BRs were used to assess the effect of hormone deficiency on the timing of floral transition. Also, plants that over-express genes encoding rate-limiting enzymes in each biosynthetic pathway were generated and the flowering time of these lines was investigated. CONCLUSIONS: Loss-of-function studies revealed a complex relationship between GAs and ABA, and between ABA and BRs, and suggested a cross-regulatory relation between GAs to BRs. Gain-of-function studies revealed that GAs were clearly limiting in their sufficiency of action, whereas increases in BRs and ABA led to a more modest phenotypic effect on floral timing. We conclude from our genetic tests that the effects of GA, ABA, and BR on timing of floral induction are only in partially coordinated action.

  5. Abscisic acid-induced rearrangement of intracellular structures associated with freezing and desiccation stress tolerance in the liverwort Marchantia polymorpha.

    Akter, Khaleda; Kato, Masahiro; Sato, Yuki; Kaneko, Yasuko; Takezawa, Daisuke

    2014-09-15

    The plant growth regulator abscisic acid (ABA) is known to be involved in triggering responses to various environmental stresses such as freezing and desiccation in angiosperms, but little is known about its role in basal land plants, especially in liverworts, representing the earliest land plant lineage. We show here that survival rate after freezing and desiccation of Marchantia polymorpha gemmalings was increased by pretreatment with ABA in the presence of increasing concentrations of sucrose. ABA treatment increased accumulation of soluble sugars in gemmalings, and sugar accumulation was further increased by addition of sucrose to the culture medium. ABA treatment of gemmalings also induced accumulation of transcripts for proteins with similarity to late embryogenesis abundant (LEA) proteins, which accumulate in association with acquisition of desiccation tolerance in maturing seeds. Observation by light and electron microscopy indicated that the ABA treatment caused fragmentation of vacuoles with increased cytosolic volume, which was more prominent in the presence of a high concentration of external sucrose. ABA treatment also increased the density of chloroplast distribution and remarkably enlarged their volume. These results demonstrate that ABA induces drastic physiological changes in liverwort cells for stress tolerance, accompanied by accumulation of protectants against dehydration and rearrangement and morphological alterations of cellular organelles. PMID:25046754

  6. Epoxycarotenoid-mediated synthesis of abscisic acid in Physcomitrella patens implicating conserved mechanisms for acclimation to hyperosmosis in embryophytes.

    Takezawa, Daisuke; Watanabe, Naoki; Ghosh, Totan Kumar; Saruhashi, Masashi; Suzuki, Atsushi; Ishiyama, Kanako; Somemiya, Shinnosuke; Kobayashi, Masatomo; Sakata, Yoichi

    2015-04-01

    Plants acclimate to environmental stress signals such as cold, drought and hypersalinity, and provoke internal protective mechanisms. Abscisic acid (ABA), a carotenoid-derived phytohormone, which increases in response to the stress signals above, has been suggested to play a key role in the acclimation process in angiosperms, but the role of ABA in basal land plants such as mosses, including its biosynthetic pathways, has not been clarified. Targeted gene disruption of PpABA1, encoding zeaxanthin epoxidase in the moss Physcomitrella patens was conducted to determine the role of endogenous ABA in acclimation processes in mosses. The generated ppaba1 plants were found to accumulate only a small amount of endogenous ABA. The ppaba1 plants showed reduced osmotic acclimation capacity in correlation with reduced dehydration tolerance and accumulation of late embryogenesis abundant proteins. By contrast, cold-induced freezing tolerance was less affected in ppaba1, indicating that endogenous ABA does not play a major role in the regulation of cold acclimation in the moss. Our results suggest that the mechanisms for osmotic acclimation mediated by carotenoid-derived synthesis of ABA are conserved in embryophytes and that acquisition of the mechanisms played a crucial role in terrestrial adaptation and colonization by land plant ancestors. PMID:25545104

  7. Putrescine is involved in Arabidopsis freezing tolerance and cold acclimation by regulating abscisic acid levels in response to low temperature.

    Cuevas, Juan C; López-Cobollo, Rosa; Alcázar, Rubén; Zarza, Xavier; Koncz, Csaba; Altabella, Teresa; Salinas, Julio; Tiburcio, Antonio F; Ferrando, Alejandro

    2008-10-01

    The levels of endogenous polyamines have been shown to increase in plant cells challenged with low temperature; however, the functions of polyamines in the regulation of cold stress responses are unknown. Here, we show that the accumulation of putrescine under cold stress is essential for proper cold acclimation and survival at freezing temperatures because Arabidopsis (Arabidopsis thaliana) mutants defective in putrescine biosynthesis (adc1, adc2) display reduced freezing tolerance compared to wild-type plants. Genes ADC1 and ADC2 show different transcriptional profiles upon cold treatment; however, they show similar and redundant contributions to cold responses in terms of putrescine accumulation kinetics and freezing sensitivity. Our data also demonstrate that detrimental consequences of putrescine depletion during cold stress are due, at least in part, to alterations in the levels of abscisic acid (ABA). Reduced expression of NCED3, a key gene involved in ABA biosynthesis, and down-regulation of ABA-regulated genes are detected in both adc1 and adc2 mutant plants under cold stress. Complementation analysis of adc mutants with ABA and reciprocal complementation tests of the aba2-3 mutant with putrescine support the conclusion that putrescine controls the levels of ABA in response to low temperature by modulating ABA biosynthesis and gene expression. PMID:18701673

  8. Integrin-like Protein Is Involved in the Osmotic Stress-induced Abscisic Acid Biosynthesis in Arabidopsis thaliana

    Bing Lü; Feng Chen; Zhong-Hua Gong; Hong Xie; Jian-Sheng Liang

    2007-01-01

    We studied the perception of plant cells to osmotic stress that leads to the accumulation of abscisic acid (ABA) in stressed Arabidopsis thaliana L. cells. A significant difference was found between protoplasts and cells in terms of their responses to osmotic stress and ABA biosynthesis, implying that cell wall and/or cell wall-plasma membrane interaction are essential in identifying osmotic stress. Western blotting and immunofluorescence localization experiments, using polyclonal antibody against human integrin β1, revealed the existence of a protein similar to the integrin protein of animals in the suspension-cultured cells located in the plasma membrane fraction.Treatment with a synthetic pentapeptide, Gly-Arg-Gly-Asp-Ser (GRGDS), which contains an RGD domain and interacts specifically with integrin protein and thus blocks the cell wall-plasma membrane interaction, significantly inhibited osmotic stress-induced ABA biosynthesis in cells, but not in protoplasts. These results demonstrate that cell wall and/or cell wall-plasma membrane interaction mediated by integrin-like proteins played important roles in osmotic stress-induced ABA biosynthesis in Arabidopsis thaliana.

  9. Jasmonate signaling involves the abscisic acid receptor PYL4 to regulate metabolic reprogramming in Arabidopsis and tobacco

    Lackman, Petri; González-Guzmán, Miguel; Tilleman, Sofie; Carqueijeiro, Inês; Pérez, Amparo Cuéllar; Moses, Tessa; Seo, Mitsunori; Kanno, Yuri; Häkkinen, Suvi T.; Van Montagu, Marc C. E.; Thevelein, Johan M.; Maaheimo, Hannu; Oksman-Caldentey, Kirsi-Marja; Rodriguez, Pedro L.; Rischer, Heiko; Goossens, Alain

    2011-01-01

    The phytohormones jasmonates (JAs) constitute an important class of elicitors for many plant secondary metabolic pathways. However, JAs do not act independently but operate in complex networks with crosstalk to several other phytohormonal signaling pathways. Here, crosstalk was detected between the JA and abscisic acid (ABA) signaling pathways in the regulation of tobacco (Nicotiana tabacum) alkaloid biosynthesis. A tobacco gene from the PYR/PYL/RCAR family, NtPYL4, the expression of which is regulated by JAs, was found to encode a functional ABA receptor. NtPYL4 inhibited the type-2C protein phosphatases known to be key negative regulators of ABA signaling in an ABA-dependent manner. Overexpression of NtPYL4 in tobacco hairy roots caused a reprogramming of the cellular metabolism that resulted in a decreased alkaloid accumulation and conferred ABA sensitivity to the production of alkaloids. In contrast, the alkaloid biosynthetic pathway was not responsive to ABA in control tobacco roots. Functional analysis of the Arabidopsis (Arabidopsis thaliana) homologs of NtPYL4, PYL4 and PYL5, indicated that also in Arabidopsis altered PYL expression affected the JA response, both in terms of biomass and anthocyanin production. These findings define a connection between a component of the core ABA signaling pathway and the JA responses and contribute to the understanding of the role of JAs in balancing tradeoffs between growth and defense. PMID:21436041

  10. Abscisic acid as an internal integrator of multiple physiological processes modulates leaf senescence onset in Arabidopsis thaliana

    Yuwei eSong

    2016-02-01

    Full Text Available Many studies have shown that exogenous abscisic acid (ABA promotes leaf abscission and senescence. However, owing to a lack of genetic evidence, ABA function in plant senescence has not been clearly defined. Here, two-leaf early-senescence mutants (eas that were screened by chlorophyll fluorescence imaging and named eas1-1 and eas1-2 showed high photosynthetic capacity in the early stage of plant growth compared with the wild type. Gene mapping showed that eas1-1 and eas1-2 are two novel ABA2 allelic mutants. Under unstressed conditions, the eas1 mutations caused plant dwarf, early germination, larger stomatal apertures, and early leaf senescence compared with those of the wild type. Flow cytometry assays showed that the cell apoptosis rate in eas1 mutant leaves was higher than that of the wild type after day 30. A significant increase in the transcript levels of several senescence-associated genes, especially SAG12, was observed in eas1 mutant plants in the early stage of plant growth. More importantly, ABA-activated calcium channel activity in plasma membrane and induced the increase of cytoplasmic calcium concentration in guard cells are suppressed due to the mutation of EAS1. In contrast, the eas1 mutants lost chlorophyll and ion leakage significant faster than in the wild type under treatment with calcium channel blocker. Hence, our results indicate that endogenous ABA level is an important factor controlling the onset of leaf senescence through Ca2+ signaling.

  11. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from 18O incorporation patterns

    Previous labeling studies of abscisic acid (ABA) with 18O2 have been mainly conducted with water-stressed leaves. In this study, 18O incorporation into ABA of stressed leaves of various species was compared with 18O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), 18O was most abundant in the carboxyl group, whereas incorporation of a second and third 18O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in 18O2. ABA from turgid bean leaves showed significant 18O incorporation, again with highest 18O enrichment in the carboxyl group. On the basis of 18O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid

  12. Meristem maintenance, auxin, jasmonic and abscisic acid pathways as a mechanism for phenotypic plasticity in Antirrhinum majus

    Weiss, Julia; Alcantud-Rodriguez, Raquel; Toksöz, Tugba; Egea-Cortines, Marcos

    2016-01-01

    Plants grow under climatic changing conditions that cause modifications in vegetative and reproductive development. The degree of changes in organ development i.e. its phenotypic plasticity seems to be determined by the organ identity and the type of environmental cue. We used intraspecific competition and found that Antirrhinum majus behaves as a decoupled species for lateral organ size and number. Crowding causes decreases in leaf size and increased leaf number whereas floral size is robust and floral number is reduced. Genes involved in shoot apical meristem maintenance like ROA and HIRZ, cell cycle (CYCD3a; CYCD3b, HISTONE H4) or organ polarity (GRAM) were not significantly downregulated under crowding conditions. A transcriptomic analysis of inflorescence meristems showed Gene Ontology enriched pathways upregulated including Jasmonic and Abscisic acid synthesis and or signalling. Genes involved in auxin synthesis such as AmTAR2 and signalling AmANT were not affected by crowding. In contrast, AmJAZ1, AmMYB21, AmOPCL1 and AmABA2 were significantly upregulated. Our work provides a mechanistic working hypothesis where a robust SAM and stable auxin signalling enables a homogeneous floral size while changes in JA and ABA signalling maybe responsible for the decreased leaf size and floral number. PMID:26804132

  13. Eucalyptus ESTs involved in the production of 9-cis epoxycarotenoid dioxygenase, a regulatory enzyme of abscisic acid production

    Iraê A. Guerrini

    2005-01-01

    Full Text Available Abscisic acid (ABA regulates stress responses in plants, and genomic tools can help us to understand the mechanisms involved in that process. FAPESP, a Brazilian research foundation, in association with four private forestry companies, has established the FORESTs database (https://forests.esalq.usp.br. A search was carried out in the Eucalyptus expressed sequence tag database to find ESTs involved with 9-cis epoxycarotenoid dioxygenase (NCED, the regulatory enzyme for ABA biosynthesis, using the basic local BLAST alignment tool. We found four clusters (EGEZLV2206B11.g, EGJMWD2252H08.g, EGBFRT3107F10.g, and EGEQFB1200H10.g, which represent similar sequences of the gene that produces NCED. Data showed that the EGBFRT3107F10.g cluster was similar to the maize (Zea mays NCED enzyme, while EGEZLV2206B11.g and EGJMWD2252H08.g clusters were similar to the avocado (Persea americana NCED enzyme. All Eucalyptus clusters were expressed in several tissues, especially in flower buds, where ABA has a special participation during the floral development process.

  14. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from sup 18 O incorporation patterns

    Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. (Michigan State University, East Lansing (USA))

    1989-12-01

    Previous labeling studies of abscisic acid (ABA) with {sup 18}O{sub 2} have been mainly conducted with water-stressed leaves. In this study, {sup 18}O incorporation into ABA of stressed leaves of various species was compared with {sup 18}O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), {sup 18}O was most abundant in the carboxyl group, whereas incorporation of a second and third {sup 18}O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in {sup 18}O{sub 2}. ABA from turgid bean leaves showed significant {sup 18}O incorporation, again with highest {sup 18}O enrichment in the carboxyl group. On the basis of {sup 18}O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid.

  15. Analysis of Global Expression Profiles of Arabidopsis Genes Under Abscisic Acid and H2O2 Applications

    Peng-Cheng Wang; Yan-Yan Du; Guo-Yong An; Yun Zhou; Chen Miao; Chun-Peng Song

    2006-01-01

    To gain insight into the coordination of gene expression profiles under abscisic acid (ABA) and H2O2 applications,global changes in gene expression in response to ABA and H2O2 in Arabidopsis seedlings were investigated using GeneChip (Santa Clara, CA, USA) arrays. Among over 24 000 genes present in the arrays, 459 transcripts were found to be significantly increased, whereas another 221 decreased following H2O2 treatment compared with control. Similar to treatment with H2O2, ABA treatment elevated the transcription of 391 genes and repressed that of 322 genes. One hundred and forty-three upregulated genes and 75 downregulated genes were shared between the two treatments and these genes were mainly involved in metabolism, signal transduction, transcription, defense, and resistance. Only two genes, which encode an APETALA2/dehydration-responsive element binding protein (AP2/DREBP) family transcriptional factor and a late embryogenesisabundant protein, were downregulated by H2O2, but upregulated by ABA. These results suggest that, similar to ABA, H2O2 plays a global role in gene transcription of Arabidopsisseedlings. The transcriptional responses induced by the application of exogenous ABA and H2O2 overlapped substantially. These two treatments regulated most of the downstream genes in a coordinated manner.

  16. Light-harvesting complexes in photosystem II regulate glutathione-induced sensitivity of Arabidopsis guard cells to abscisic acid.

    Jahan, Md Sarwar; Nozulaidi, Mohd; Khairi, Mohd; Mat, Nashriyah

    2016-05-20

    Light-harvesting complexes (LHCs) in photosystem II (PSII) regulate glutathione (GSH) functions in plants. To investigate whether LHCs control GSH biosynthesis that modifies guard cell abscisic acid (ABA) sensitivity, we evaluated GSH content, stomatal aperture, reactive oxygen species (ROS), weight loss and plant growth using a ch1-1 mutant that was defective of LHCs and compared this with wild-type (WT) Arabidopsis thaliana plants. Glutathione monoethyl ester (GSHmee) increased but 1-chloro-2,4 dinitrobenzene (CDNB) decreased the GSH content in the guard cells. The guard cells of the ch1-1 mutants accumulated significantly less GSH than the WT plants. The guard cells of the ch1-1 mutants also showed higher sensitivity to ABA than the WT plants. The CDNB treatment increased but the GSHmee treatment decreased the ABA sensitivity of the guard cells without affecting ABA-induced ROS production. Dark and light treatments altered the GSH content and stomatal aperture of the guard cells of ch1-1 and WT plants, irrespective of CDNB and GSHmee. The ch1-1 mutant contained fewer guard cells and displayed poor growth, late flowering and stumpy weight loss compared with the WT plants. This study suggests that defective LHCs reduced the GSH content in the guard cells and increased sensitivity to ABA, resulting in stomatal closure. PMID:26970687

  17. Overexpression of OsWRKY72 gene interferes in the abscisic acid signal and auxin transport pathway of Arabidopsis

    Song Yu; Chen Ligang; Zhang Liping; Yu Diqiu

    2010-09-01

    Through activating specific transcriptional programmes, plants can launch resistance mechanisms to stressful environments and acquire a new equilibrium between development and defence. To screen the rice WRKY transcription factor which functions in abiotic stress tolerance and modulates the abscisic acid (ABA) response, we generated a whole array of 35S-OsWRKY transgenic Arabidopsis. In this study, we report that 35S-OsWRKY72 transgenic Arabidopsis, whose seed germination was retarded under normal conditions, emerged more sensitive to mannitol, NaCl, ABA stresses and sugar starvation than vector plants. Meanwhile, 35S-OsWRKY72 transgenic Arabidopsis displayed early flowering, reduced apical dominance, lost high temperature-induced hypocotyl elongation response, and enhanced gravitropism response, which were similar to the auxin-related gene mutants aux1, axr1 and bud1. Further, semi-quantitative RT-PCR showed that the expression patterns of three auxin-related genes AUX1, AXR1 and BUD1 were significantly altered in rosette leaves and inflorescences of 35S-OsWRKY72 plants compared with control Arabidopsis, and two ABA-related genes ABA2 and ABI4 were induced in 35S-OsWRKY72 seedlings. In addition, northern blot analysis indicated that, in rice, OsWRKY72 was inducible by polyethylene glycol (PEG), NaCl, naphthalene acetic acid (NAA), ABA and 42°C, similar to its orthologue AtWRKY75 in Arabidopsis, implying that these two WRKY genes might be required for multiple physiological processes in their plants. Together, these results suggest that OsWRKY72 interferes in the signal cross-talk between the ABA signal and auxin transport pathway in transgenic Arabidopsis.

  18. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Ravi eValluru

    2016-04-01

    Full Text Available Although plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT group maintained or increased shoot dry weight (SDW while the drought-susceptible (DS group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM of ABA increased shoot relative growth rate (RGR in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early–stage selection tool aiding genotype selection for stress tolerance.

  19. Foliar Abscisic Acid-To-Ethylene Accumulation and Response Regulate Shoot Growth Sensitivity to Mild Drought in Wheat.

    Valluru, Ravi; Davies, William J; Reynolds, Matthew P; Dodd, Ian C

    2016-01-01

    Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM) of ABA increased shoot relative growth rate (RGR) in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor) spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early-stage selection tool aiding genotype selection for stress tolerance. PMID:27148292

  20. Effect of Abscisic Acid and Polyethylene Glycol on the Synchronization of Somatic Embryo Development in Date Palm (Phoenix dactylifera L.

    Abdulaziz M. Al-Bahrany

    2012-01-01

    Full Text Available Somatic embryogenesis provides the best method for commercial micropropagation of date palm (Phoenix dactylifera L.; however, a current limitation is the lack of synchronization of developing somatic embryos. The objective of this study was to evaluate the effect of Abscisic Acid (ABA and polyethylene glycol (PEG combinations on the synchronization of embryo development in date palm cell suspension. Callus maintained on MS medium containing 54 μM Naphthalene Acetic Acid (NAA and 7 μM 2-isopentenyladenine (2iP was transferred to regeneration liquid medium supplemented with ABA at 0-100 μM and PEG at 0-15%. Maximum fresh culture weight was obtained with 10% PEG in the absence of ABA. The addition of as low as 1 μM ABA to the suspensions inhibited growth. In the absence of ABA, increasing PEG concentration increased total somatic embryo numbers reaching a maximum number at 10% PEG. Various embryo sizes differing in abundance were associated with different treatments. The highest percentage of medium size embryos, 52%, was obtained at 10 μM ABA; whereas, the highest percentage of small embryos was obtained at 50-100 μM ABA. The small embryos exhibited a state of synchronization. Although, treating suspensions with ABA and PEG affected embryo size distribution, germination was influenced by embryo developmental phase, expressed in size. Germination of 43, 63, 52 and 23% was obtained from the small, medium, large and very large embryos, respectively. Retardation of somatic embryo development caused by ABA can be further exploited to optimize culture synchronization.

  1. Abscisic acid enhances tolerance of wheat seedlings to drought and regulates transcript levels of genes encoding ascorbate-glutathione biosynthesis.

    Wei, Liting; Wang, Lina; Yang, Yang; Wang, Pengfei; Guo, Tiancai; Kang, Guozhang

    2015-01-01

    Glutathione (GSH) and ascorbate (ASA) are associated with the abscisic acid (ABA)-induced abiotic tolerance in higher plant, however, its molecular mechanism remains obscure. In this study, exogenous application (10 μM) of ABA significantly increased the tolerance of seedlings of common wheat (Triticum aestivum L.) suffering from 5 days of 15% polyethylene glycol (PEG)-stimulated drought stress, as demonstrated by increased shoot lengths and shoot and root dry weights, while showing decreased content of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Under drought stress conditions, ABA markedly increased content of GSH and ASA in both leaves and roots of ABA-treated plants. Temporal and spatial expression patterns of eight genes encoding ASA and GSH synthesis-related enzymes were measured using quantitative real-time reverse transcription polymerase chain reaction (qPCR). The results showed that ABA temporally regulated the transcript levels of genes encoding ASA-GSH cycle enzymes. Moreover, these genes exhibited differential expression patterns between the root and leaf organs of ABA-treated wheat seedlings during drought stress. These results implied that exogenous ABA increased the levels of GSH and ASA in drought-stressed wheat seedlings in time- and organ-specific manners. Moreover, the transcriptional profiles of ASA-GSH synthesis-related enzyme genes in the leaf tissue were compared between ABA- and salicylic acid (SA)-treated wheat seedlings under PEG-stimulated drought stress, suggesting that they increased the content of ASA and GSH by differentially regulating expression levels of ASA-GSH synthesis enzyme genes. Our results increase our understanding of the molecular mechanism of ABA-induced drought tolerance in higher plants. PMID:26175737

  2. Translation initiation factor 5A in Picrorhiza is up-regulated during leaf senescence and in response to abscisic acid.

    Parkash, Jai; Vaidya, Tanmay; Kirti, Shruti; Dutt, Som

    2014-05-25

    Translation initiation, the first step of protein synthesis process is the principal regulatory step controlling translation and involves a pool of translation initiation factors. In plants, from recent studies it is becoming evident that these translation initiation factors impact various aspects of plant growth and development in addition to their role in protein synthesis. Eukaryotic translation initiation factor eIF5A is one such factor which functions in start site selection for the eIF2-GTP-tRNAi ternary complex within the ribosomal-bound preinitiation complex and also stabilizes the binding of GDP to eIF2. In the present study we have cloned and analysed a gene (eIF5a) encoding eIF5A from Picrorhiza (Picrorhiza kurrooa Royle ex Benth.) a medicinal plant of the western Himalayan region. The full length eIF5a cDNA consisted of 838 bp with an open reading frame of 480 bp, 88 bp 5' untranslated region and 270 bp 3' untranslated region. The deduced eIF5A protein contained 159 amino acids with a molecular weight of 17.359 kDa and an isoelectric point of 5.59. Secondary structure analysis revealed eIF5A having 24.53% α-helices, 8.81% β-turns, 23.27% extended strands and 43.40% random coils. pk-eIF5a transcript was found to be expressing during the active growth phase as well as during leaf senescence stage, however, highest expression was observed during leaf senescence stage. Further, its expression was up-regulated in response to exogenous application of abscisic acid. Both high intensity as well as low intensity light decreased the expression of pk-eIF5a. The findings suggest eIF5a to be an important candidate to develop genetic engineering based strategies for delaying leaf senescence. PMID:24656625

  3. Water stress responses of tomato mutants impaired in hormone biosynthesis reveal abscisic acid, jasmonic acid and salicylic acid interactions

    Valeria eMuñoz

    2015-11-01

    Full Text Available To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient and flacca (flc, ABA-deficient mutants together with the naphthalene/salicylate hydroxylase (NahG transgenic (SA-deficient line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1 and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3 expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1 was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress.

  4. Water Stress Responses of Tomato Mutants Impaired in Hormone Biosynthesis Reveal Abscisic Acid, Jasmonic Acid and Salicylic Acid Interactions.

    Muñoz-Espinoza, Valeria A; López-Climent, María F; Casaretto, José A; Gómez-Cadenas, Aurelio

    2015-01-01

    To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient) and flacca (flc, ABA-deficient) mutants together with the naphthalene/salicylate hydroxylase (NahG) transgenic (SA-deficient) line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT) plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1) and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3) expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1) was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress. PMID:26635826

  5. β-Aminobutyric acid increases abscisic acid accumulation and desiccation tolerance and decreases water use but fails to improve grain yield in two spring wheat cultivars under soil drying

    Du, Yan-Lei; Wang, Zhen-Yu; Fan, Jing-Wei; Turner, Neil C.; Wang, Tao; Li, Feng-Min

    2012-01-01

    A pot experiment was conducted to investigate the effect of the non-protein amino acid, β-aminobutyric acid (BABA), on the homeostasis between reactive oxygen species (ROS) and antioxidant defence during progressive soil drying, and its relationship with the accumulation of abscisic acid (ABA), water use, grain yield, and desiccation tolerance in two spring wheat (Triticum aestivum L.) cultivars released in different decades and with different yields under drought. Drenching the soil with 100...

  6. Cross-talk between calcium-calmodulin and nitric oxide in abscisic acid signaling in leaves of maize plants

    Jianrong Sang; Aying Zhang; Fan Lin; Mingpu Tan; Mingyi Jiang

    2008-01-01

    Using pharmacological and biochemical approaches,the signaling pathways between hydrogen peroxide (H2O2),calcium (Ca2+)-calmodulin (CAM),and nitric oxide (NO) in abscisic acid (ABA)-induced antioxidant defense were investigated in leaves of maize (Zea mays L.) plants.Treatments with ABA,H2O2,and CaCI2 induced increases in the generation of NO in maize mesophyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves.However,such increases were blocked by the pretreatments with Ca2+ inhibitors and CaM antagonists.Meanwhile,pretreatments with two NOS inhibitors also suppressed the Ca2+-induced increase in the production of NO.On the other hand,treatments with ABA and the NO donor sodium nitroprusside (SNP) also led to increases in the concentration of cytosolic Ca2+ in protoplasts of mesophyll cells and in the expression of calmodulin 1 (CaMI) gene and the contents of CaM in leaves of maize plants,and the increases induced by ABA were reduced by the pretreatments with a NO scavenger and a NOS inhibitor.Moreover,SNP-induced increases in the expression of the antioxidant genes superoxide dismutase 4 (SOD4),cytosolic ascorbate peroxidase (cAPX),and glutathione reductase 1 (GRI) and the activities of the chloroplastic and cytosolic antioxidant enzymes were arrested by the pretreatments with Ca2+ inhibitors and CaM antagonists.Our results suggest that Ca2+-CaM functions both upstream and downstream of NO production,which is mainly from NOS,in ABA- and H2O2-induced antioxidant defense in leaves of maize plants.

  7. Genome-Wide Analysis of MicroRNA Responses to the Phytohormone Abscisic Acid in Populus euphratica.

    Duan, Hui; Lu, Xin; Lian, Conglong; An, Yi; Xia, Xinli; Yin, Weilun

    2016-01-01

    MicroRNA (miRNA) is a type of non-coding small RNA with a regulatory function at the posttranscriptional level in plant growth development and in response to abiotic stress. Previous studies have not reported on miRNAs responses to the phytohormone abscisic acid (ABA) at a genome-wide level in Populus euphratica, a model tree for studying abiotic stress responses in woody plants. Here we analyzed the miRNA response to ABA at a genome-wide level in P. euphratica utilizing high-throughput sequencing. To systematically perform a genome-wide analysis of ABA-responsive miRNAs in P. euphratica, nine sRNA libraries derived from three groups (control, treated with ABA for 1 day and treated with ABA for 4 days) were constructed. Each group included three libraries from three individual plantlets as biological replicate. In total, 151 unique mature sequences belonging to 75 conserved miRNA families were identified, and 94 unique sequences were determined to be novel miRNAs, including 56 miRNAs with miRNA(*) sequences. In all, 31 conserved miRNAs and 31 novel miRNAs response to ABA significantly differed among the groups. In addition, 4132 target genes were predicted for the conserved and novel miRNAs. Confirmed by real-time qPCR, expression changes of miRNAs were inversely correlated with the expression profiles of their putative targets. The Populus special or novel miRNA-target interactions were predicted might be involved in some biological process related stress tolerance. Our analysis provides a comprehensive view of how P. euphratica miRNA respond to ABA, and moreover, different temporal dynamics were observed in different ABA-treated libraries. PMID:27582743

  8. Ectopic expression of ABSCISIC ACID 2/GLUCOSE INSENSITIVE 1 in Arabidopsis promotes seed dormancy and stress tolerance.

    Lin, Pei-Chi; Hwang, San-Gwang; Endo, Akira; Okamoto, Masanori; Koshiba, Tomokazu; Cheng, Wan-Hsing

    2007-02-01

    Abscisic acid (ABA) is an important phytohormone that plays a critical role in seed development, dormancy, and stress tolerance. 9-cis-Epoxycarotenoid dioxygenase is the key enzyme controlling ABA biosynthesis and stress tolerance. In this study, we investigated the effect of ectopic expression of another ABA biosynthesis gene, ABA2 (or GLUCOSE INSENSITIVE 1 [GIN1]) encoding a short-chain dehydrogenase/reductase in Arabidopsis (Arabidopsis thaliana). We show that ABA2-overexpressing transgenic plants with elevated ABA levels exhibited seed germination delay and more tolerance to salinity than wild type when grown on agar plates and/or in soil. However, the germination delay was abolished in transgenic plants showing ABA levels over 2-fold higher than that of wild type grown on 250 mm NaCl. The data suggest that there are distinct mechanisms underlying ABA-mediated inhibition of seed germination under diverse stress. The ABA-deficient mutant aba2, with a shorter primary root, can be restored to normal root growth by exogenous application of ABA, whereas transgenic plants overexpressing ABA2 showed normal root growth. The data reflect that the basal levels of ABA are essential for maintaining normal primary root elongation. Furthermore, analysis of ABA2 promoter activity with ABA2::beta-glucuronidase transgenic plants revealed that the promoter activity was enhanced by multiple prolonged stresses, such as drought, salinity, cold, and flooding, but not by short-term stress treatments. Coincidently, prolonged drought stress treatment led to the up-regulation of ABA biosynthetic and sugar-related genes. Thus, the data support ABA2 as a late expression gene that might have a fine-tuning function in mediating ABA biosynthesis through primary metabolic changes in response to stress. PMID:17189333

  9. Effects of abscisic acid and high osmoticum on storage protein gene expression in microspore embryos of Brassica napus

    Storage protein gene expression, characteristic of mid- to late embryogenesis, was investigated in microspore embryos of rapeseed (Brassica napus). These embryos, derived from the immature male gametophyte, accumulate little or no detectable napin or cruciferin mRNA when cultured on hormone-free medium containing 13% sucrose. The addition of abscisic acid (ABA) to the medium results in an increase in detectable transcripts encoding both these polypeptides. Storage protein mRNA is induced at 1 micromolar ABA with maximum stimulation occurring between 5 and 50 micromolar. This hormone induction results in a level of storage protein mRNA that is comparable to that observed in zygotic embryos of an equivalent morphological stage. Effects similar to that of ABA are noted when 12.5% sorbitol is added to the microspore embryo medium (osmotic potential = 25.5 bars). Time course experiments, to study the induction of napin and cruciferin gene expression demonstrated that the ABA effect occurred much more rapidly than the high osmoticum effect, although after 48 hours, the levels of napin or cruciferin mRNA detected were similar in both treatments. This difference in the rates of induction is consistent with the idea that the osmotic effect may be mediated by ABA which is synthesized in response to the reduced water potential. Measurements of ABA (by gas chromatography-mass spectrometry using [2H6]ABA as an internal standard) present in microspore embryos during sorbitol treatment and in embryos treated with 10 micromolar ABA were performed to investigate this possibility. Within 2 hours of culture on high osmoticum the level of ABA increased substantially and significantly above control and reached a maximum concentration within 24 hours. This elevated concentration was maintained for 48 hours after culturing and represents a sixfold increase over control embryos

  10. Abscisic acid, a stress hormone helps in improving water relations and yield of sunflower (helianthus annuus l.) hybrids under drought

    Genotypic variation in water relations under drought is an important index of studying drought tolerance of crops. Abscisic acid (ABA) application helped in mitigating drought stress by improving water relations and yield. Three sunflower hybrids viz., DK-4040 (tall stature), S-278 (medium stature) and SF-187 (short stature) were subjected to different irrigation and ABA application regimes i.e., four irrigations (25 days after sowing (DAS), at bud initiation, at flower initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing, at flower initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing, at flower initiation and at achene formation) and with ABA spray at bud initiation, three irrigations (25 days after sowing), at bud initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing), at bud initiation and at achene formation) and with ABA spray at flower initiation. The experiment was laid out in randomized complete block design with split plot arrangement and had three replications. Exogenous application of ABA under drought at either stage (bud or flower initiation) was helpful in ameliorating drought stress by improving water relations and yield of sunflower hybrids; however response was better when ABA was applied under drought at bud initiation than at flower initiation stage. Sunflower hybrid DK- 4040 showed better enhancement of drought tolerance by exogenous application of ABA under drought than SF-187 and S-278 because it showed more improvement in water potential, osmotic potential, turgor pressure, relative leaf water contents and achene yield. (author)

  11. Structural basis for basal activity and autoactivation of abscisic acid (ABA) signaling SnRK2 kinases

    Ng, Ley-Moy; Soon, Fen-Fen; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Suino-Powell, Kelly M.; Chalmers, Michael J.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric (Van Andel); (Scripps); (Purdue); (NU Singapore)

    2014-10-02

    Abscisic acid (ABA) is an essential hormone that controls plant growth, development, and responses to abiotic stresses. Central for ABA signaling is the ABA-mediated autoactivation of three monomeric Snf1-related kinases (SnRK2.2, -2.3, and -2.6). In the absence of ABA, SnRK2s are kept in an inactive state by forming physical complexes with type 2C protein phosphatases (PP2Cs). Upon relief of this inhibition, SnRK2 kinases can autoactivate through unknown mechanisms. Here, we report the crystal structures of full-length Arabidopsis thaliana SnRK2.3 and SnRK2.6 at 1.9- and 2.3-{angstrom} resolution, respectively. The structures, in combination with biochemical studies, reveal a two-step mechanism of intramolecular kinase activation that resembles the intermolecular activation of cyclin-dependent kinases. First, release of inhibition by PP2C allows the SnRK2s to become partially active because of an intramolecular stabilization of the catalytic domain by a conserved helix in the kinase regulatory domain. This stabilization enables SnRK2s to gain full activity by activation loop autophosphorylation. Autophosphorylation is more efficient in SnRK2.6, which has higher stability than SnRK2.3 and has well-structured activation loop phosphate acceptor sites that are positioned next to the catalytic site. Together, these data provide a structural framework that links ABA-mediated release of PP2C inhibition to activation of SnRK2 kinases.

  12. Arabidopsis plastid AMOS1/EGY1 integrates abscisic acid signaling to regulate global gene expression response to ammonium stress

    Li, Baohai

    2012-10-12

    Ammonium (NH4 +) is a ubiquitous intermediate of nitrogen metabolism but is notorious for its toxic effects on most organisms. Extensive studies of the underlying mechanisms of NH4 + toxicity have been reported in plants, but it is poorly understood how plants acclimate to high levels of NH4 +. Here, we identified an Arabidopsis (Arabidopsis thaliana) mutant, ammonium overly sensitive1 (amos1), that displays severe chlorosis under NH4 + stress. Map-based cloning shows amos1 to carry a mutation in EGY1 (for ethylene-dependent, gravitropism-deficient, and yellow-green-like protein1), which encodes a plastid metalloprotease. Transcriptomic analysis reveals that among the genes activated in response to NH4 +, 90% are regulated dependent on AMOS1/ EGY1. Furthermore, 63% of AMOS1/EGY1-dependent NH4 +-activated genes contain an ACGTG motif in their promoter region, a core motif of abscisic acid (ABA)-responsive elements. Consistent with this, our physiological, pharmacological, transcriptomic, and genetic data show that ABA signaling is a critical, but not the sole, downstream component of the AMOS1/EGY1-dependent pathway that regulates the expression of NH4 +-responsive genes and maintains chloroplast functionality under NH4 + stress. Importantly, abi4 mutants defective in ABA-dependent and retrograde signaling, but not ABA-deficient mutants, mimic leaf NH4 + hypersensitivity of amos1. In summary, our findings suggest that an NH4 +-responsive plastid retrograde pathway, which depends on AMOS1/EGY1 function and integrates with ABA signaling, is required for the regulation of expression of the presence of high NH4 + levels. © 2012 American Society of Plant Biologists. All Rights Reserved.

  13. Abscisic acid activates a Ca2+-calmodulin-stimulated protein kinase involved in antioxidant defense in maize leaves

    Shucheng Xu

    2010-01-01

     The role of a calcium-dependent and calmodulin(CaM)stimulated protein kinase in abscisic acid(ABA)-induced antioxidant defense was determined in leaves of maize (Zea mays).In-gel kinase assays showed that treatments with ABA or H2O2 induced the activation of a 49-kDa protein kinase and a 52-kDa protein kinase significantly.Furthermore,we showed that the 52-kDa protein kinase has the characteristics of CaM-stimulating activity and is sensitive to calcium-CaM-dependent protein kinase Ⅱ (CaMK Ⅱ)inhibitor KN-93 or CaM antagonist W-7.Treatments with ABA or H2O2 not only induced the acti vation of the 52-kDa protein kinase,but also enhanced the total activities of the antioxidant enzymes,including catalase,ascorbate peroxidase,glutathione reductase,and superoxide dismutase.Such enhancements were blocked by pretreatment with a CaMK inhibitor and a reactive oxygen species(ROS)inhibitor or scavenger.Pretreatment with the CaMK inhibitor also substantially arrested the ABA-induced H2O2 production.Kinase activity enhancements induced by ABA were attenuated by pretreatment with an ROS inhibitor or scavenger.These results suggest that the 52-kDa CaMK is involved in ABA-induced antioxidant defense and that cross-talk between CaMK and H2O2 plays a pivotal role in ABA signaling.We infer that CaMK acts both upstream and downstream of H2O2,but mainly acts between ABA and H2O2 in ABA-induced antioxidant-defensive signaling.

  14. ZmABA2, an interacting protein of ZmMPK5, is involved in abscisic acid biosynthesis and functions.

    Ma, Fangfang; Ni, Lan; Liu, Libo; Li, Xi; Zhang, Huan; Zhang, Aying; Tan, Mingpu; Jiang, Mingyi

    2016-02-01

    In maize (Zea mays), the mitogen-activated protein kinase ZmMPK5 has been shown to be involved in abscisic acid (ABA)-induced antioxidant defence and to enhance the tolerance of plants to drought, salt stress and oxidative stress. However, the underlying molecular mechanisms are poorly understood. Here, using ZmMPK5 as bait in yeast two-hybrid screening, a protein interacting with ZmMPK5 named ZmABA2, which belongs to a member of the short-chain dehydrogenase/reductase family, was identified. Pull-down assay and bimolecular fluorescence complementation analysis and co-immunoprecipitation test confirmed that ZmMPK5 interacts with ZmABA2 in vitro and in vivo. Phosphorylation of Ser173 in ZmABA2 by ZmMPK5 was shown to increase the activity of ZmABA2 and the protein stability. Various abiotic stimuli induced the expression of ZmABA2 in leaves of maize plants. Pharmacological, biochemical and molecular biology and genetic analyses showed that both ZmMPK5 and ZmABA2 coordinately regulate the content of ABA. Overexpression of ZmABA2 in tobacco plants was found to elevate the content of ABA, regulate seed germination and root growth under drought and salt stress and enhance the tolerance of tobacco plants to drought and salt stress. These results suggest that ZmABA2 is a direct target of ZmMPK5 and is involved in ABA biosynthesis and functions. PMID:26096642

  15. Abscisic acid refines the synthesis of chloroplast proteins in maize (Zea mays in response to drought and light.

    Xiuli Hu

    Full Text Available To better understand abscisic acid (ABA regulation of the synthesis of chloroplast proteins in maize (Zea mays L. in response to drought and light, we compared leaf proteome differences between maize ABA-deficient mutant vp5 and corresponding wild-type Vp5 green and etiolated seedlings exposed to drought stress. Proteins extracted from the leaves of Vp5 and vp5 seedlings were used for two-dimensional electrophoresis (2-DE and subsequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry (MS. After Coomassie brilliant blue staining, approximately 450 protein spots were reproducibly detected on 2-DE gels. A total of 36 differentially expressed protein spots in response to drought and light were identified using MALDI-TOF MS and their subcellular localization was determined based on the annotation of reviewed accession in UniProt Knowledgebase and the software prediction. As a result, corresponding 13 proteins of the 24 differentially expressed protein spots were definitely localized in chloroplasts and their expression was in an ABA-dependent way, including 6 up-regulated by both drought and light, 5 up-regulated by drought but down-regulated by light, 5 up-regulated by light but down-regulated by drought; 5 proteins down-regulated by drought were mainly those involved in photosynthesis and ATP synthesis. Thus, the results in the present study supported the vital role of ABA in regulating the synthesis of drought- and/or light-induced proteins in maize chloroplasts and would facilitate the functional characterization of ABA-induced chloroplast proteins in C(4 plants.

  16. Regulation of auxin, abscisic acid and salicylic acid levels by ascorbate application under heat stress in sensitive and tolerant maize leaves.

    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

  17. Molecular cloning and characterization of drought stress responsive abscisic acid-stress-ripening (Asr 1) gene from wild jujube, Ziziphus nummularia (Burm.f.) Wight & Arn.

    Padaria, Jasdeep Chatrath; Yadav, Radha; Tarafdar, Avijit; Lone, Showkat Ahmad; Kumar, Kanika; Sivalingam, Palaiyur Nanjappan

    2016-08-01

    Drought is a calamitous abiotic stress hampering agricultural productivity all over the world and its severity is likely to increase further. Abscisic acid-stress-ripening proteins (ASR), are a group of small hydrophilic proteins which are induced by abscisic acid, stress and ripening in many plants. In the present study, ZnAsr 1 gene was fully characterized for the first time from Ziziphus nummularia, which is one of the most low water forbearing plant. Full length ZnAsr 1 gene was characterised and in silico analysis of ZnASR1 protein was done for predicting its phylogeny and physiochemical properties. To validate transcriptional pattern of ZnAsr 1 in response to drought stress, expression profiling in polyethylene glycol (PEG) induced Z. nummularia seedlings was studied by RT-qPCR analysis and heterologous expression of the recombinant ZnAsr1 in Escherichia coli. The nucleotide sequence analysis revealed that the complete open reading frame of ZnAsr 1 is 819 bp long encoding a protein of 273 amino acid residues, consisting of a histidine rich N terminus with an abscisic acid/water deficit stress domain and a nuclear targeting signal at the C terminus. In expression studies, ZnAsr 1 gene was found to be highly upregulated under drought stress and recombinant clones of E. coli cells expressing ZnASR1 protein showed better survival in PEG containing media. ZnAsr1 was proven to enhance drought stress tolerance in the recombinant E.coli cells expressing ZnASR1. The cloned ZnAsr1 after proper validation in a plant system, can be used to develop drought tolerant transgenic crops. PMID:27209581

  18. Onset of herbivore-induced resistance in systemic tissue primed for jasmonate-dependent defenses is activated by abscisic acid

    Irene A. Vos

    2013-12-01

    Full Text Available In Arabidopsis, the MYC2 transcription factor on the one hand and the AP2/ERF transcription factors ORA59 and ERF1 on the other hand regulate distinct branches of the jasmonic acid (JA signaling pathway in an antagonistic fashion, co-regulated by abscisic acid (ABA and ethylene, respectively. Feeding by larvae of the specialist herbivorous insect Pieris rapae (small cabbage white butterfly results in activation of the MYC-branch and concomitant suppression of the ERF-branch in insect-damaged leaves. Here we investigated differential JA signaling activation in undamaged systemic leaves of P. rapae-infested plants. We found that the MYC2 transcription factor gene was induced both in the local insect-damaged leaves and the systemic undamaged leaves of P. rapae-infested Arabidopsis plants. However, in contrast to the insect-damaged leaves, the undamaged tissue did not show activation of the MYC-branch marker gene VSP1. Comparison of the hormone signal signature revealed that the levels of JA and (+-7-iso-jasmonoyl-L-isoleucine (JA-Ile raised to similar extents in locally damaged and systemically undamaged leaves, but the production of ABA and the JA precursor 12-oxo-phytodienoic acid (OPDA was enhanced only in the local herbivore-damaged leaves, and not in the distal undamaged leaves. Challenge of undamaged leaves of pre-infested plants with either P. rapae larvae or exogenously applied ABA led to potentiated expression levels of MYC2 and VSP1, with the latter reaching extremely high expression levels. Moreover, P. rapae-induced resistance, as measured by reduction of caterpillar growth on pre-infested plants, was blocked in the ABA biosynthesis mutant aba2-1, that was also impaired in P. rapae-induced expression of VSP1. Together, these results suggest that ABA is a crucial regulator of herbivore-induced resistance by activating primed JA-regulated defense responses upon secondary herbivore attack in Arabidopsis.

  19. Calcium partitioning and allocation and blossom-end rot development in tomato plants in response to whole-plant and fruit-specific abscisic acid treatments

    Tonetto de Freitas, Sergio; McElrone, Andrew J.; Shackel, Kenneth A.; Mitcham, Elizabeth J

    2013-01-01

    The mechanisms regulating Ca2+ partitioning and allocation in plants and fruit remain poorly understood. The objectives of this study were to determine Ca2+ partitioning and allocation in tomato plants and fruit in response to whole-plant and fruit-specific abscisic acid (ABA) treatments, as well as to analyse the effect of changes in Ca2+ partitioning and allocation on fruit susceptibility to the Ca2+ deficiency disorder blossom-end rot (BER) under water stress conditions. Tomato plants of t...

  20. Low Temperature-Induced 30 (LTI30) positively regulates drought stress resistance in Arabidopsis: effect on abscisic acid sensitivity and hydrogen peroxide accumulation

    Shi, Haitao; Chen, Yinhua; Qian, Yongqiang; Chan, Zhulong

    2015-01-01

    As a dehydrin belonging to group II late embryogenesis abundant protein (LEA) family, Arabidopsis Low Temperature-Induced 30 (LTI30)/XERO2 has been shown to be involved in plant freezing stress resistance. However, the other roles of AtLTI30 remain unknown. In this study, we found that the expression of AtLTI30 was largely induced by drought stress and abscisic acid (ABA) treatments. Thereafter, AtLTI30 knockout mutants and overexpressing plants were isolated to investigate the possible invol...

  1. Polyphenolic responses of grapevine berries to light, temperature, oxidative stress, abscisic acid and jasmonic acid show specific developmental-dependent degrees of metabolic resilience to perturbation.

    Degu, Asfaw; Ayenew, Biruk; Cramer, Grant R; Fait, Aaron

    2016-12-01

    Grape-berries are exposed to a plethora of abiotic and biotic stimuli during their development. The developmental and temporal regulation of grape berry polyphenol metabolism in response to various cues was investigated using LC-QTOF-MS based metabolite profiling. High light (2500μmolm(-2)s(-1)), high temperature (40°C), jasmonic acid (200μM), menadione (120μM) and abscisic acid (3.026mM) treatments were applied to detached berries. Greater magnitudes of metabolite fluctuations characterize the pre-veraison berries than the veraison stage in response to the treatments. Furthermore, a tighter co-response of metabolic processes was shown at veraison, likely supporting the resilience to change in response to stress. High temperature and ABA treatments led to greater magnitudes of change during the course of the experiment. The present study demonstrates the occurrence of differential patterns of metabolic responses specific to individual cues and berry developmental stage, which in the field are commonly associated and thus hardly discernable. PMID:27374601

  2. Analysis of ADP-glucose pyrophosphorylase expression during turion formation induced by abscisic acid in Spirodela polyrhiza (greater duckweed

    Wang Wenqin

    2012-01-01

    Full Text Available Abstract Background Aquatic plants differ in their development from terrestrial plants in their morphology and physiology, but little is known about the molecular basis of the major phases of their life cycle. Interestingly, in place of seeds of terrestrial plants their dormant phase is represented by turions, which circumvents sexual reproduction. However, like seeds turions provide energy storage for starting the next growing season. Results To begin a characterization of the transition from the growth to the dormant phase we used abscisic acid (ABA, a plant hormone, to induce controlled turion formation in Spirodela polyrhiza and investigated their differentiation from fronds, representing their growth phase, into turions with respect to morphological, ultra-structural characteristics, and starch content. Turions were rich in anthocyanin pigmentation and had a density that submerged them to the bottom of liquid medium. Transmission electron microscopy (TEM of turions showed in comparison to fronds shrunken vacuoles, smaller intercellular space, and abundant starch granules surrounded by thylakoid membranes. Turions accumulated more than 60% starch in dry mass after two weeks of ABA treatment. To further understand the mechanism of the developmental switch from fronds to turions, we cloned and sequenced the genes of three large-subunit ADP-glucose pyrophosphorylases (APLs. All three putative protein and exon sequences were conserved, but the corresponding genomic sequences were extremely variable mainly due to the invasion of miniature inverted-repeat transposable elements (MITEs into introns. A molecular three-dimensional model of the SpAPLs was consistent with their regulatory mechanism in the interaction with the substrate (ATP and allosteric activator (3-PGA to permit conformational changes of its structure. Gene expression analysis revealed that each gene was associated with distinct temporal expression during turion formation. APL2 and

  3. Regulation of the High-Affinity Nitrate Transport System in Wheat Roots by Exogenous Abscisic Acid and Glutamine

    Chao Cai; Xue-Qiang Zhao; Yong-Guan Zhu; Bin Li; Yi-Ping Tong; Zhen-Sheng Li

    2007-01-01

    Nitrate is a major nitrogen (N) source for most crops.Nitrate uptake by root cells is a key step of nitrogen metabolism and has been widely studied at the physiological and molecular levels.Understanding how nitrate uptake is regulated will help us engineer crops with improved nitrate uptake efficiency.The present study investigated the regulation of the high-affinity nitrate transport system (HATS) by exogenous abscisic acid (ABA) and glutamine (Gin) in wheat (Triticum aestivum L.) roots.Wheat seedlings grown in nutrient solution containing 2 mmollL nitrate as the only nitrogen source for 2 weeks were deprived of N for 4d and were then transferred to nutrient solution containing 50 μmol/L ABA, and 1 mmol/L Gin in the presence or absence of 2 mmol/L nitrate for 0, 0.5, 1, 2, 4, and 8 h.Treated wheat plants were then divided into two groups.One group of plants was used to investigate the mRNA levels of the HATS components NRT2 and NAR2 genes in roots through semi-quantitative RT-PCR approach, and the other set of plants were used to measure high-affinity nitrate influx rates in a nutrient solution containing 0.2 mmol/L 15 N-labeled nitrate.The results showed that exogenous ABA induced the expression of the TaNRT2.1, TaNRT2.2, TaNRT2.3, TaNAR2.1, and TaNAR2.2 genes in roots when nitrate was not present in the nutrient solution, but did not further enhance the induction of these genes by nitrate.Glutamine, which has been shown to inhibit the expression of NRT2 genes when nitrate is present in the growth media, did not inhibit this induction.When Gin was supplied to a nitrate-free nutrient solution, the expression of these five genes in roots was induced.These results imply that the inhibition by Gin of NRT2 expression occurs only when nitrate is present in the growth media.Although exogenous ABA and Gin induced HATS genes in the roots of wheat, they did not induce nitrate influx.

  4. The small ethylene response factor ERF96 is involved in the regulation of the abscisic acid response in Arabidopsis

    Xiaoping eWang

    2015-11-01

    Full Text Available Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene Response Factors (ERFs are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97 and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay results indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed

  5. Regulation of erucic acid accumulation in oilseed rape (Brassica napus L.). Effects of temperature and abscisic acid.

    Wilmer, J.A.

    1997-01-01

    Vegetable oils are an important commodity world-wide with an annual production of about 70 million tonnes. Oilseed rape is one of the four major crops, providing about 10% of the total production. Quality of vegetable oils is determined by the fatty acid composition of the triacylglycerols (TAG) that constitute such oils. These fatty acids comprise a range of chain lengths and desaturated and oxidised residues. A small group of fatty acids dominates the edible oils which are the predominant p...

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

    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

  7. Regulation of erucic acid accumulation in oilseed rape (Brassica napus L.). Effects of temperature and abscisic acid.

    Wilmer, J.A.

    1997-01-01

    Vegetable oils are an important commodity world-wide with an annual production of about 70 million tonnes. Oilseed rape is one of the four major crops, providing about 10% of the total production. Quality of vegetable oils is determined by the fatty acid composition of the triacylglycerols (TAG) tha

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

    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

  9. Changes in abundance of an abscisic acid-responsive, early cysteine-labeled metallothionein transcript during pollen embryogenesis in bread wheat (Triticum aestivum).

    Reynolds, T L; Crawford, R L

    1996-12-01

    A clone for an embryoid-abundant, early cysteine-labeled metallothionein (EcMt) gene has been isolated from a wheat pollen embryoid cDNA library. The transcript of this gene was only expressed in embryogenic microspores, pollen embryoids, and developing zygotic embryos of wheat. Accumulation of the EcMt mRNA showed a direct and positive correlation with an increase of the plant hormone, abscisic acid (ABA) in developing pollen embryoids. Treating cultures with an inhibitor of ABA biosynthesis, fluridone, suppressed not only ABA accumulation but also the appearance of the EcMt gene transcript and the ability of microspores to form embryoids. These results suggest that the EcMt gene may act as a molecular marker for pollen embryogenesis because ABA biosynthesis is accompanied by the increased expression of the EcMt transcript that coincides with the differentiation of pollen embryoids in wheat anther cultures. PMID:8980534

  10. A maize calcium-dependent protein kinase gene, ZmCPK4, positively regulated abscisic acid signaling and enhanced drought stress tolerance in transgenic Arabidopsis.

    Jiang, Shanshan; Zhang, Dan; Wang, Li; Pan, Jiaowen; Liu, Yang; Kong, Xiangpei; Zhou, Yan; Li, Dequan

    2013-10-01

    Calcium-dependent protein kinases (CDPKs) play essential roles in calcium-mediated signal transductions in plant response to abiotic stress. Several members have been identified to be regulators for plants response to abscisic acid (ABA) signaling. Here, we isolated a subgroup I CDPK gene, ZmCPK4, from maize. Quantitative real time PCR (qRT-PCR) analysis revealed that the ZmCPK4 transcripts were induced by various stresses and signal molecules. Transient and stable expression of the ZmCPK4-GFP fusion proteins revealed ZmCPK4 localized to the membrane. Moreover, overexpression of ZmCPK4 in the transgenic Arabidopsis enhanced ABA sensitivity in seed germination, seedling growth and stomatal movement. The transgenic plants also enhanced drought stress tolerance. Taken together, the results suggest that ZmCPK4 might be involved in ABA-mediated regulation of stomatal closure in response to drought stress. PMID:23911729

  11. Up-regulating the abscisic acid inactivation gene ZmABA8ox1b contributes to seed germination heterosis by promoting cell expansion.

    Li, Yangyang; Wang, Cheng; Liu, Xinye; Song, Jian; Li, Hongjian; Sui, Zhipeng; Zhang, Ming; Fang, Shuang; Chu, Jinfang; Xin, Mingming; Xie, Chaojie; Zhang, Yirong; Sun, Qixin; Ni, Zhongfu

    2016-04-01

    Heterosis has been widely used in agriculture, but the underlying molecular principles are still largely unknown. During seed germination, we observed that maize (Zea mays) hybrid B73/Mo17 was less sensitive than its parental inbred lines to exogenous abscisic acid (ABA), and endogenous ABA content in hybrid embryos decreased more rapidly than in the parental inbred lines. ZmABA8ox1b, an ABA inactivation gene, was consistently more highly up-regulated in hybrid B73/Mo17 than in its parental inbred lines at early stages of seed germination. Moreover, ectopic expression of ZmABA8ox1b obviously promoted seed germination in Arabidopsis Remarkably, microscopic observation revealed that cell expansion played a major role in the ABA-mediated maize seed germination heterosis, which could be attributed to the altered expression of cell wall-related genes. PMID:27034328

  12. In vitro Transient Expression System of Latex C-serum was used for Analysis of Hevein Promoter in Response to Abscisic Acid in Hevea brasiliensis

    Xiao-Wen Fei; Xiao-Dong Deng

    2008-01-01

    Hevein has been found to be an essential element in coagulation of rubber particles in latex of rubber trees. In a previous study, we cloned a 1 241-bp fragment of a 5' upstream region of the hevein gene by genome walking. This fragment was analyzed by a 5' end nested deletion method in the present study, fused with a uidA (gus) gene to produce a series of tested constructs, which were transferred into C-serum of latex and the Gus activities were detected. Results showed that the fragment from -749 to -292 was sufficient for expression of gus gene in latex, and the fragment from -292 to -168 was crucial in response to abscisic acid inducement. In a transient transgenic test of rubber leaf with particle bombardment, construct Hev749 conferred gus-specific expression in veins, in which the latex tubes mainly distributed. This implies that the fragment from -749 to -292 was laticiferous-specific.

  13. The putative E3 ubiquitin ligase ECERIFERUM9 regulates abscisic acid biosynthesis and response during seed germination and postgermination growth in arabidopsis

    Zhao, Huayan

    2014-05-08

    The ECERIFERUM9 (CER9) gene encodes a putative E3 ubiquitin ligase that functions in cuticle biosynthesis and the maintenance of plant water status. Here, we found that CER9 is also involved in abscisic acid (ABA) signaling in seeds and young seedlings of Arabidopsis (Arabidopsis thaliana). The germinated embryos of the mutants exhibited enhanced sensitivity to ABA during the transition from reversible dormancy to determinate seedling growth. Expression of the CER9 gene is closely related to ABA levels and displays a similar pattern to that of ABSCISIC ACID-INSENSITIVE5 (ABI5), which encodes a positive regulator of ABA responses in seeds. cer9 mutant seeds exhibited delayed germination that is independent of seed coat permeability. Quantitative proteomic analyses showed that cer9 seeds had a protein profile similar to that of the wild type treated with ABA. Transcriptomics analyses revealed that genes involved in ABA biosynthesis or signaling pathways were differentially regulated in cer9 seeds. Consistent with this, high levels of ABA were detected in dry seeds of cer9. Blocking ABA biosynthesis by fluridone treatment or by combining an ABA-deficient mutation with cer9 attenuated the phenotypes of cer9. Whereas introduction of the abi1-1, abi3-1, or abi4-103 mutation could completely eliminate the ABA hypersensitivity of cer9, introduction of abi5 resulted only in partial suppression. These results indicate that CER9 is a novel negative regulator of ABA biosynthesis and the ABA signaling pathway during seed germination. © 2014 American Society of Plant Biologists. All Rights Reserved.

  14. Transport and concentration of abscisic acid (ABA) and auxin (IAA) in deciduous and coniferous trees. Transport und Gehalt von Abscisinsaeure (ABA) und Auxin (IAA) in Laub- und Nadelblaettern

    Hartung, W.

    1988-09-01

    Abscisic acid and indoleacetic acid were chosen to examine whether intact deciduous and coniferous tissues from spruce, hemlock fir, spinage, barley and sorrel or isolated mesophyll protoplasts from barley and closing cell preparations from Valerianella locusta are affected by sulphur dioxide in terms of changes in the concentration, transportation and distribution of such plant hormones. The distribution of phytohormones like ABA and IAA over the individual cell compartments is determined by the different pH gradients of the latter. Owing to their acidity these hormones are accumulated in alkaline cell inclusion bodies like chloroplasts and cytosol. Potentially acid air pollutants like SO{sub 2} and NO{sub x} lead to acidification of previously alkaline cell compartments, due to which fact the cellular pH gradients are reduced. This, in turn, gives rise to a redistribution of phytohormones to the effect that certain target cells such as closing cells of leaves or meristem cells come under the influence of altered hormone concentrations and compositions. This is bound to affect the processes controlling the development, growth and stress behaviour of plants. (orig.) With 55 refs., 2 tabs., 16 figs.

  15. Effect of abscisic acid on biochemical constituents, enzymatic and non enzymatic antioxidant status of lettuce (Lactuca sativa L. under varied irrigation regimes

    Mohamed A. Al Muhairi

    2015-12-01

    Full Text Available Economically important vegetable crop lettuce (Lactuca sativa L. of family Asteraceae was selected for the present investigation. It is being cultivated in UAE due to its commercial importance. In lettuce cultivation, the major problem is the requirement of large quantities of irrigation water. The present study was aimed to reduce the water consumption of lettuce cultivation; for that, a varied irrigation regime was used with the application of abscisic acid (ABA. The parameters studied were biochemical constituents, antioxidant potential and antioxidant enzymes’ activities in lettuce plants under drought stress and its response to ABA under stress. Drought stress caused an increase in the biochemical constituents like proline and amino acid contents when compared with control and also increased under individual ABA treatments and treatments under drought stress. The non-enzymatic antioxidant molecules like ascorbate and α-tocopherol showed significant increase under drought condition in lettuce. ABA slightly reduced these contents. The antioxidant enzymes like superoxide dismutase, catalase and peroxidase showed significant increase under drought condition and ABA caused significant enhancement in these antioxidant enzymes under drought stress and also in unstressed conditions, thereby protecting the plants from the deleterious effects of drought stress. From the results of this investigation, it can be concluded that ABA in 10 mg g−1 can be used as a potential tool to minimise the drought stress effects in lettuce cultivation.

  16. Nucleotide Variation in the NCED3 Region of Arabidopsis thaliana and its Association Study with Abscisic Acid Content under Drought Stress

    Gang-Ping Hao; Xiu-Hai Zhang; Yong-Qin Wang; Zhong-Yi Wu; Cong-Lin Huang

    2009-01-01

    Drought tolerance is a comprehensive quantitative trait that is being understood further at the molecular genetic level. Abscisic acid (ABA) is the main drought-induced hormone that regulates the expression of many genes related to drought responses. 9-cis-epoxycarotenoid dioxygenase (NCED3) is thought to be a key enzyme in ABA biosynthesis. In this paper, we measured the ABA content increase under drought stress, and sequenced and compared the sequence of AtNCED3 among 22 Arabidopsis thaliana accessions. The results showed that the fold of ABA content increase under drought stress was highly variable among these accessions. High density single nucleotide polymorphism (SNP) and insertion/deletion (indel) were found in the AtNCED3 region, on average one SNP per 87.4 bp and one indel per 502 bp. Nucleotide diversity was significantly lower in the coding region than that in non-coding regions. The results of an association study with ANOVA analysis suggested that the 274th site (P←→S) and the 327th site (P←→R) amino acid variations might be the cause of ABA content increase of 163av accession under drought stress.

  17. The potato suberin feruloyl transferase FHT which accumulates in the phellogen is induced by wounding and regulated by abscisic and salicylic acids.

    Boher, Pau; Serra, Olga; Soler, Marçal; Molinas, Marisa; Figueras, Mercè

    2013-08-01

    The present study provides new insights on the role of the potato (Solanum tuberosum) suberin feruloyl transferase FHT in native and wound tissues, leading to conclusions about hitherto unknown properties of the phellogen. In agreement with the enzymatic role of FHT, it is shown that its transcriptional activation and protein accumulation are specific to tissues that undergo suberization such as the root boundary layers of the exodermis and the endodermis, along with the tuber periderm. Remarkably, FHT expression and protein accumulation within the periderm is restricted to the phellogen derivative cells with phellem identity. FHT levels in the periderm are at their peak near harvest during periderm maturation, with the phellogen becoming meristematically inactive and declining thereafter. However, periderm FHT levels remain high for several months after harvest, suggesting that the inactive phellogen retains the capacity to synthesize ferulate esters. Tissue wounding induces FHT expression and the protein accumulates from the first stages of the healing process onwards. FHT is up-regulated by abscisic acid and down-regulated by salicylic acid, emphasizing the complex regulation of suberin synthesis and wound healing. These findings open up new prospects important for the clarification of the suberization process and yield important information with regard to the skin quality of potatoes. PMID:23918964

  18. Induction of Protection against Paraquat-induced Oxidative Damage by Abscisic Acid in Maize Leaves is Mediated through Mitogen-activated Protein Kinase

    Hai-Dong Ding; Xiao-Hua Zhang; Shu-Cheng Xu; Li-Li Sun; Ming-Yi Jiang; A-Ying Zhang; Yin-Gen Jin

    2009-01-01

    Mitogen-activated protein kinase (MAPK) cascade has been shown to be important components In stress signal trans-duction pathway. In the present study, protection of maize seedlings (Zea mays L.) against paraquat-generated oxidative toxicity by abscisic acid (ABA), its association with MAPK and ZmMPK5, a candidate for MAPK were investigated. Treatment of maize leaves with exogenous ABA led to significant decreases in the content of malondialdehyde, the percentage of ion leakage and the level of protein oxidation (in terms of carbonyl groups) under paraquat (PQ) stress. However, such decreases were blocked by the pretreatment with two MAPK kinase inhibitors PD98059 and U0126. The damage caused by PQ was further aggravated by inhibitors. Two inhibitors also suppressed the total activities of the antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2). Besides, treatment with PQ stimulated the activation of a 46 kDa MAPK, which was identified as ZmMPK5 by in-gel kinase assay with immunoprecipitation. These results reveal that ABA-induced protection against PQ-generated oxidative damage is mediated through MAPK cascade in maize leaves, in which ZmMPK5, a candidate for MAPK, is demonstrated to be involved.

  19. Genetic Analysis of Physcomitrella patens Identifies ABSCISIC ACID NON-RESPONSIVE, a Regulator of ABA Responses Unique to Basal Land Plants and Required for Desiccation Tolerance[OPEN

    Kamisugi, Yasuko; Trinh, Chi H.; Schmutz, Jeremy; Muchero, Wellington; Melkonian, Michael; Rothfels, Carl J.; Li, Fay-Wei; Larsson, Anders; Edwards, Thomas A.

    2016-01-01

    The anatomically simple plants that first colonized land must have acquired molecular and biochemical adaptations to drought stress. Abscisic acid (ABA) coordinates responses leading to desiccation tolerance in all land plants. We identified ABA nonresponsive mutants in the model bryophyte Physcomitrella patens and genotyped a segregating population to map and identify the ABA NON-RESPONSIVE (ANR) gene encoding a modular protein kinase comprising an N-terminal PAS domain, a central EDR domain, and a C-terminal MAPKKK-like domain. anr mutants fail to accumulate dehydration tolerance-associated gene products in response to drought, ABA, or osmotic stress and do not acquire ABA-dependent desiccation tolerance. The crystal structure of the PAS domain, determined to 1.7-Å resolution, shows a conserved PAS-fold that dimerizes through a weak dimerization interface. Targeted mutagenesis of a conserved tryptophan residue within the PAS domain generates plants with ABA nonresponsive growth and strongly attenuated ABA-responsive gene expression, whereas deleting this domain retains a fully ABA-responsive phenotype. ANR orthologs are found in early-diverging land plant lineages and aquatic algae but are absent from more recently diverged vascular plants. We propose that ANR genes represent an ancestral adaptation that enabled drought stress survival of the first terrestrial colonizers but were lost during land plant evolution. PMID:27194706

  20. Identification of quantitative trait locus for abscisic acid responsiveness on chromosome 5A and association with dehydration tolerance in common wheat seedlings.

    Iehisa, Julio C M; Matsuura, Takakazu; Mori, Izumi C; Takumi, Shigeo

    2014-01-15

    The phytohormone abscisic acid (ABA) plays important roles in response to environmental stress as well as in seed maturation and dormancy. In common wheat, quantitative trait loci (QTLs) for ABA responsiveness at the seedling stage have been reported on chromosomes 1B, 2A, 3A, 6D and 7B. In this study, we identified a novel QTL for ABA responsiveness on chromosome 5A using an F2 population derived from a cross between the common wheat cultivar Chinese Spring (CS) and a chromosome substitution line of CS with chromosome 5A of cultivar Hope (Hope5A). This QTL was found in a similar chromosomal region to previously reported QTLs for drought tolerance and seed dormancy. Physiological characterization of the QTL revealed a small effect on dehydration tolerance and seed dormancy. The rate of water loss from leaves during dehydration was lower, and transcript accumulation of the cold responsive (COR)/late embryogenesis abundant (LEA) genes Wrab18 and Wdhn13 tended to be higher under dehydration stress in F2 individuals carrying the Hope allele of the QTL, which also showed higher ABA responsiveness than the CS allele-carrying individuals. Seed dormancy of individuals carrying the Hope allele also tended to be lower than those carrying the CS allele. Our results suggest that variation in ABA responsiveness among common wheat cultivars is at least partly determined by the 5A QTL, and that this QTL contributes to development of dehydration and preharvest sprouting tolerance. PMID:24331416

  1. A new role for an old enzyme: Nitrate reductase-mediated nitric oxide generation is required for abscisic acid-induced stomatal closure in Arabidopsis thaliana

    Desikan, Radhika; Griffiths, Rachael; Hancock, John; Neill, Steven

    2002-01-01

    The plant hormone abscisic acid (ABA), synthesized in response to water-deficit stress, induces stomatal closure via activation of complex signaling cascades. Recent work has established that nitric oxide (NO) is a key signaling molecule mediating ABA-induced stomatal closure. However, the biosynthetic origin of NO in guard cells has not yet been resolved. Here, we provide pharmacological, physiological, and genetic evidence that NO synthesis in Arabidopsis guard cells is mediated by the enzyme nitrate reductase (NR). Guard cells of wild-type Arabidopsis generate NO in response to treatment with ABA and nitrite, a substrate for NR. Moreover, NR-mediated NO synthesis is required for ABA-induced stomatal closure. However, in the NR double mutant, nia1, nia2 that has diminished NR activity, guard cells do not synthesize NO nor do the stomata close in response to ABA or nitrite, although stomatal opening is still inhibited by ABA. Furthermore, by using the ABA-insensitive (ABI) abi1–1 and abi2–1 mutants, we show that the ABI1 and ABI2 protein phosphatases are downstream of NO in the ABA signal-transduction cascade. These data demonstrate a previously uncharacterized signaling role for NR, that of mediating ABA-induced NO synthesis in Arabidopsis guard cells. PMID:12446847

  2. Osabc1k8, an abc1-like kinase gene, mediates abscisic acid sensitivity and dehydration tolerance response in rice seedlings

    The activity of bc1 complex kinase (ABC1K) protein family, which widely exists in prokaryotes and eukaryotes, consists of 15 members in rice, and the role of this family in plants has not yet been studied in details. In this study, a novel function of OsABC1K8 (LOC-Os06g48770), a member of rice ABC1K family, was characterized. The transcript level of OsABC1K8 changes in response to salt, dehydration, cold, PEG, oxidative (H/sub 2/O/sub 2/) stresses, or abscisic acid (ABA) treatment. Overexpression of OsABC1K8 significantly increased sensitivity to dehydration and reduced sensitivity to ABA. In the contrast, RNAi transgenic lines displayed significantly reduced sensitivity to dehydration stress and increased sensitivity to ABA. Furthermore, the transcriptional levels of several ABA/stress-regulated responsive genes were suppressed in OsABC1K8 over-expressing plants under dehydration stress. In conclusion, our results suggested that OsABC1K8 is a negative regulator in response to dehydration stress through an ABA-dependent pathway. (author)

  3. Distinct abscisic acid signaling pathways for modulation of guard cell versus mesophyll cell potassium channels revealed by expression studies in Xenopus laevis oocytes

    Sutton, F.; Paul, S. S.; Wang, X. Q.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

    2000-01-01

    Regulation of guard cell ion transport by abscisic acid (ABA) and in particular ABA inhibition of a guard cell inward K(+) current (I(Kin)) is well documented. However, little is known concerning ABA effects on ion transport in other plant cell types. Here we applied patch clamp techniques to mesophyll cell protoplasts of fava bean (Vicia faba cv Long Pod) plants and demonstrated ABA inhibition of an outward K(+) current (I(Kout)). When mesophyll cell protoplast mRNA (mesophyll mRNA) was expressed in Xenopus laevis oocytes, I(Kout) was generated that displayed similar properties to I(Kout) observed from direct analysis of mesophyll cell protoplasts. I(Kout) expressed by mesophyll mRNA-injected oocytes was inhibited by ABA, indicating that the ABA signal transduction pathway observed in mesophyll cells was preserved in the frog oocytes. Co-injection of oocytes with guard cell protoplast mRNA and cRNA for KAT1, an inward K(+) channel expressed in guard cells, resulted in I(Kin) that was similarly inhibited by ABA. However, oocytes co-injected with mesophyll mRNA and KAT1 cRNA produced I(Kin) that was not inhibited by ABA. These results demonstrate that the mesophyll-encoded signaling mechanism could not substitute for the guard cell pathway. These findings indicate that mesophyll cells and guard cells use distinct and different receptor types and/or signal transduction pathways in ABA regulation of K(+) channels.

  4. Maturation in Corymbia torelliana × C. citriodora Stock Plants: Effects of Pruning Height on Shoot Production, Adventitious Rooting Capacity, Stem Anatomy, and Auxin and Abscisic Acid Concentrations

    Ivar Wendling

    2015-10-01

    Full Text Available Repeated pruning of stock plants is a common approach to delaying maturation and maintaining the propagation ability of cuttings, but little is known about the hormonal or anatomical basis for this phenomenon. We tested the effect of two different stock-plant pruning heights (15 cm and 30 cm on shoot production, rooting capacity and rooted cutting vigour of six clones of the eucalypt Corymbia torelliana × C. citriodora. We determined whether differences in rooting potential were related to indole-3-acetic (IAA and abscisic acid (ABA concentrations, or the degree of lignification or sclerification, of the cuttings. Maintaining stock plants at 15 cm height sometimes reduced the production of stem cuttings. However, it often increased the ensuing percentage of cuttings that formed roots, with mean rooting across all clones increasing from 30%–53%. Therefore, the number of rooted cuttings produced by short stock plants was similar to, or higher than, the number produced by tall stock plants. Cuttings from shorter stock plants had faster root elongation and occasionally greater root dry mass, shoot dry mass or shoot height than cuttings from tall stock plants. These differences in rooting potential were generally not related to differences in IAA or ABA concentrations of the cuttings or to differences in their stem anatomy. Pruning at the lower height was more effective in maintaining clonal juvenility, supporting previous findings that stock plant maturation is a limiting factor in clonal propagation of Corymbia torelliana × C. citriodora.

  5. AtPUB 19, a U-Box E3 Ubiquitin Ligase, Negatively Regulates Abscisic Acid and Drought Responses in Arabidopsis thaliana

    Yong-Chang Liu; Yao-Rong Wu; Xia-He Huang; Jie Sun; Qi Xie

    2011-01-01

    Ubiquitination is an important protein post-translational modification,which is involved in various cellular processes in higher plants,and U-box E3 ligases play important roles in diverse functions in eukaryotes.Here,we describe the functions of Arabidopsis thaliana PUB19 (AtPUB19),which we demonstrated in an in vitro assay to encode a U-box type E3 ubiquitin ligase.AtPUB19 was up-regulated by drought,salt,cold,and abscisic acid (ABA).Down-regulation of AtPUB19led to hypersensitivity to ABA,enhanced ABA-induced stomatal closing,and enhanced drought tolerance,while AtPUB 19overexpression resulted in the reverse phenotypes.Molecular analysis showed that the expression levels of a number of ABA and stress marker genes were altered in both AtPUB 19 overexpressing and atpub 19-1 mutant plants.In summary,our data show that AtPUB19 negatively regulates ABA and drought responses in A.thaliana.

  6. The pepper late embryogenesis abundant protein CaLEA1 acts in regulating abscisic acid signaling, drought and salt stress response.

    Lim, Chae Woo; Lim, Sohee; Baek, Woonhee; Lee, Sung Chul

    2015-08-01

    As sessile organisms, plants are constantly challenged by environmental stresses, including drought and high salinity. Among the various abiotic stresses, osmotic stress is one of the most important factors for growth and significantly reduces crop productivity in agriculture. Here, we report a function of the CaLEA1 protein in the defense responses of plants to osmotic stress. Our analyses showed that the CaLEA1 gene was strongly induced in pepper leaves exposed to drought and increased salinity. Furthermore, we determined that the CaLEA1 protein has a late embryogenesis abundant (LEA)_3 homolog domain highly conserved among other known group 5 LEA proteins and is localized in the processing body. We generated CaLEA1-silenced peppers and CaLEA1-overexpressing (OX) transgenic Arabidopsis plants to evaluate their responses to dehydration and high salinity. Virus-induced gene silencing of CaLEA1 in pepper plants conferred enhanced sensitivity to drought and salt stresses, which was accompanied by high levels of lipid peroxidation in dehydrated and NaCl-treated leaves. CaLEA1-OX plants exhibited enhanced sensitivity to abscisic acid (ABA) during seed germination and in the seedling stage; furthermore, these plants were more tolerant to drought and salt stress than the wild-type plants because of enhanced stomatal closure and increased expression of stress-responsive genes. Collectively, our data suggest that CaLEA1 positively regulates drought and salinity tolerance through ABA-mediated cell signaling. PMID:25302464

  7. Putrescine Is Involved in Arabidopsis Freezing Tolerance and Cold Acclimation by Regulating Abscisic Acid Levels in Response to Low Temperature1

    Cuevas, Juan C.; López-Cobollo, Rosa; Alcázar, Rubén; Zarza, Xavier; Koncz, Csaba; Altabella, Teresa; Salinas, Julio; Tiburcio, Antonio F.; Ferrando, Alejandro

    2008-01-01

    The levels of endogenous polyamines have been shown to increase in plant cells challenged with low temperature; however, the functions of polyamines in the regulation of cold stress responses are unknown. Here, we show that the accumulation of putrescine under cold stress is essential for proper cold acclimation and survival at freezing temperatures because Arabidopsis (Arabidopsis thaliana) mutants defective in putrescine biosynthesis (adc1, adc2) display reduced freezing tolerance compared to wild-type plants. Genes ADC1 and ADC2 show different transcriptional profiles upon cold treatment; however, they show similar and redundant contributions to cold responses in terms of putrescine accumulation kinetics and freezing sensitivity. Our data also demonstrate that detrimental consequences of putrescine depletion during cold stress are due, at least in part, to alterations in the levels of abscisic acid (ABA). Reduced expression of NCED3, a key gene involved in ABA biosynthesis, and down-regulation of ABA-regulated genes are detected in both adc1 and adc2 mutant plants under cold stress. Complementation analysis of adc mutants with ABA and reciprocal complementation tests of the aba2-3 mutant with putrescine support the conclusion that putrescine controls the levels of ABA in response to low temperature by modulating ABA biosynthesis and gene expression. PMID:18701673

  8. Mapping intercellular CO2 mole fraction (Ci) in rosa rubiginosa leaves fed with abscisic acid by using chlorophyll fluorescence imaging. Significance Of ci estimated from leaf gas exchange

    Meyer; Genty

    1998-03-01

    Imaging of photochemical yield of photosystem II (PSII) computed from leaf chlorophyll fluorescence images and gas-exchange measurements were performed on Rosa rubiginosa leaflets during abscisic acid (ABA) addition. In air ABA induced a decrease of both the net CO2 assimilation (An) and the stomatal water vapor conductance (gs). After ABA treatment, imaging in transient nonphotorespiratory conditions (0.1% O2) revealed a heterogeneous decrease of PSII photochemical yield. This decline was fully reversed by a transient high CO2 concentration (7400 mol mol-1) in the leaf atmosphere. It was concluded that ABA primarily affected An by decreasing the CO2 supply at ribulose-1,5-bisphosphate carboxylase/oxygenase. Therefore, the An versus intercellular mole fraction (Ci) relationship was assumed not to be affected by ABA, and images of Ci and gs were constructed from images of PSII photochemical yield under nonphotorespiratory conditions. The distribution of gs remained unimodal following ABA treatment. A comparison of calculations of Ci from images and gas exchange in ABA-treated leaves showed that the overestimation of Ci estimated from gas exchange was only partly due to heterogeneity. This overestimation was also attributed to the cuticular transpiration, which largely affects the calculation of the leaf conductance to CO2, when leaf conductance to water is low. PMID:9501127

  9. Low Temperature-Induced 30 (LTI30 positively regulates drought stress resistance in Arabidopsis: effect on abscisic acid sensitivity and hydrogen peroxide accumulation

    Haitao eShi

    2015-10-01

    Full Text Available As a dehydrin belonging to group II late embryogenesis abundant protein (LEA family, Arabidopsis Low Temperature-Induced 30 (LTI30/XERO2 has been shown to be involved in plant freezing stress resistance. However, the other roles of AtLTI30 remain unknown. In this study, we found that the expression of AtLTI30 was largely induced by drought stress and abscisic acid (ABA treatments. Thereafter, AtLTI30 knockout mutants and overexpressing plants were isolated to investigate the possible involvement of AtLTI30 in ABA and drought stress responses. AtLTI30 knockout mutants were less sensitive to ABA-mediated seed germination, while AtLTI30 overexpressing plants were more sensitive to ABA compared with wild type (WT. Consistently, the AtLTI30 knockout mutants displayed decreased drought stress resistance, while the AtLTI30 overexpressing plants showed improved drought stress resistance compared with WT, as evidenced by a higher survival rate and lower leaf water loss than WT after drought stress. Moreover, manipulation of AtLTI30 expression positively regulated the activities of catalases (CATs and endogenous proline content, as a result, negatively regulated drought stress-triggered hydrogen peroxide (H2O2 accumulation. All these results indicate that AtLTI30 is a positive regulator of plant drought stress resistance, partially through the modulation of ABA sensitivity, H2O2 and proline accumulation.

  10. Chloride-inducible transient apoplastic alkalinizations induce stomata closure by controlling abscisic acid distribution between leaf apoplast and guard cells in salt-stressed Vicia faba.

    Geilfus, Christoph-Martin; Mithöfer, Axel; Ludwig-Müller, Jutta; Zörb, Christian; Muehling, Karl H

    2015-11-01

    Chloride stress causes the leaf apoplast transiently to alkalize, an event that is presumed to contribute to the ability of plants to adapt to saline conditions. However, the initiation of coordinated processes downstream of the alkalinization is unknown. We hypothesize that chloride-inducible pH dynamics are a key chemical feature modulating the compartmental distribution of abscisic acid (ABA) and, as a consequence, affecting stomata aperture. Apoplastic pH and stomata aperture dynamics in intact Vicia faba leaves were monitored by microscopy-based ratio imaging and porometric measurements of stomatal conductance. ABA concentrations in leaf apoplast and guard cells were compared with pH dynamics by gas-chromatography-mass-spectrometry (GC-MS) and liquid-chromatography-tandem-mass spectrometry (LC-MS/MS). Results demonstrate that, upon chloride addition to roots, an alkalizing factor that initiates the pH dynamic propagates from root to leaf in a way similar to xylem-distributed water. In leaves, it induces a systemic transient apoplastic alkalinization that causes apoplastic ABA concentration to increase, followed by an elevation of endogenous guard cell ABA. We conclude that the transient alkalinization, which is a remote effect of chloride stress, modulates the compartmental distribution of ABA between the leaf apoplast and the guard cells and, in this way, is instrumental in inducing stomata closure during the beginning of salinity. PMID:26096890

  11. Expression of Stipa purpurea SpCIPK26 in Arabidopsis thaliana Enhances Salt and Drought Tolerance and Regulates Abscisic Acid Signaling

    Zhou, Yanli; Sun, Xudong; Yang, Yunqiang; Li, Xiong; Cheng, Ying; Yang, Yongping

    2016-01-01

    Stipa purpurea (S. purpurea) is the dominant plant species in the alpine steppe of the Qinghai-Tibet Plateau, China. It is highly resistant to cold and drought conditions. However, the underlying mechanisms regulating the stress tolerance are unknown. In this study, a CIPK gene from S. purpurea (SpCIPK26) was isolated. The SpCIPK26 coding region consisted of 1392 bp that encoded 464 amino acids. The protein has a highly conserved catalytic structure and regulatory domain. The expression of SpCIPK26 was induced by drought and salt stress. SpCIPK26 overexpression in Arabidopsis thaliana (A. thaliana) plants provided increased tolerance to drought and salt stress in an abscisic acid (ABA)-dependent manner. Compared with wild-type A. thaliana plants, SpCIPK26-overexpressing plants had higher survival rates, water potentials, and photosynthetic efficiency (Fv/Fm), as well as lower levels of reactive oxygen species (ROS) following exposure to drought and salt stress. Gene expression analyses indicated stress-inducible genes (RD29A, RD29B, and ABF2) and a ROS-scavenger gene (CAT1) were upregulated in SpCIPK26-overexpressing plants after stress treatments. All of these marker genes are associated with ABA-responsive cis-acting elements. Additionally, the similarities in the gene expression patterns following ABA, mannitol, and NaCl treatments suggest SpCIPK26 has an important role during plant responses to drought and salt stress and in regulating ABA signaling. PMID:27338368

  12. Changes in the levels of abscisic acid and its metabolites in excised leaf blades of Xanthium strumarium during and after water stress

    Zeevaart, J.A.D.

    1980-10-01

    The time course of abscisic acid (ABA) accumulation during water stress and of degradation following rehydration was investigated by analyzing the levels of ABA and its metabolites phaseic acid (PA) and alkalihydrolyzable conjugated ABA in excised leaf blades of Xanthium strumarium. Initial purification was by reverse-phase, preparative, high performance liquid chromatography (HPLC) which did not require prior partitioning. ABA and PA were purified further by analytical HPLC with a ..mu..Bondapak-NH/sub 2/ column, and quantified by GLC with an electron capture detector. The ABA content of stressed leaves increased for 4 to 5 hours and then leveled off due to a balance between synthesis and degradation. Since PA accumulated at a constant rate throughout the wilting period, it was concluded that the rate of ABA synthesis decreased after the first 4 to 5 hours stress. Conjugated ABA increased at a low rate during stress. This is interpreted to indicate that free ABA was converted to the conjugated form, rather than the reverse. Following rehydration of wilted leaves, the ABA level immediately ceased increasing; it remained constant for 1 hour and then declined rapidly to the prestress level over a 2- to 3-hour period with a concomitant rise in the PA level. In contrast to the rapid disappearance of ABA after relief of stress, the high PA content of rehydrated leaves declined only slowly. The level of conjugated ABA did not change following rehydration, indicating that conjugation of ABA was irreversible. Detached Xanthium leaves that were subjected to a wilting-recovery-rewilting cycle in darkness responded to the second wilting period by formation of the same amount of ABA as accumulated after the first stress period.

  13. OsDMI3 Is a Novel Component of Abscisic Acid Signaling in the Induction of Antioxidant Defense in Leaves of Rice

    Ben Shi; Lan Ni; Aying Zhang; Jianmei Cao; Hong Zhang; Tingting Qin; Mingpu Tan; Jianhua Zhang; Mingyi Jiang

    2012-01-01

    Ca2+ and calmodulin (CaM) have been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense.However,it is unknown whether Ca2+/CaM-dependent protein kinase (CCaMK) is involved in the process.In the present study,the role of rice CCaMK,OsDMI3,in ABA-induced antioxidant defense was investigated in leaves of rice (Oryza sativa) plants.Treatments with ABA,H2O2,and polyethylene glycol (PEG) induced the expression of OsDMI3 and the activity of OsDMI3,and H2O2 is required for the ABA-induced increases in the expression and the activity of OsDMI3 under water stress.Subcellular localization analysis showed that OsDMI3 is located in the nucleus,the cytoplasm,and the plasma membrane.The analysis of the transient expression of OsDMI3 in rice protoplasts and the RNA interference (RNAi) silencing of OsDMI3 in rice protoplasts showed that OsDMI3 is required for ABA-induced increases in the expression and the activities of superoxide dismutase (SOD) and catalase (CAT).Further,the oxidative damage induced by higher concentrations of PEG and H2O2 was aggravated in the mutant of OsDMI3.Moreover,the analysis of the RNAi silencing of OsDMI3 in protoplasts and the mutant of OsDMI3 showed that higher levels of H2O2 accumulation require OsDMI3 activation in ABA signaling,but the initial H2O2 production induced by ABA is not dependent on the activation of OsDMI3 in leaves of rice plants.Our data reveal that OsDMI3 is an important component in ABA-induced antioxidant defense in rice.

  14. Gene expression and metabolite profiling of developing highbush blueberry fruit indicates transcriptional regulation of flavonoid metabolism and activation of abscisic acid metabolism.

    Zifkin, Michael; Jin, Alena; Ozga, Jocelyn A; Zaharia, L Irina; Schernthaner, Johann P; Gesell, Andreas; Abrams, Suzanne R; Kennedy, James A; Constabel, C Peter

    2012-01-01

    Highbush blueberry (Vaccinium corymbosum) fruits contain substantial quantities of flavonoids, which are implicated in a wide range of health benefits. Although the flavonoid constituents of ripe blueberries are known, the molecular genetics underlying their biosynthesis, localization, and changes that occur during development have not been investigated. Two expressed sequence tag libraries from ripening blueberry fruit were constructed as a resource for gene identification and quantitative real-time reverse transcription-polymerase chain reaction primer design. Gene expression profiling by quantitative real-time reverse transcription-polymerase chain reaction showed that flavonoid biosynthetic transcript abundance followed a tightly regulated biphasic pattern, and transcript profiles were consistent with the abundance of the three major classes of flavonoids. Proanthocyanidins (PAs) and corresponding biosynthetic transcripts encoding anthocyanidin reductase and leucoanthocyanidin reductase were most concentrated in young fruit and localized predominantly to the inner fruit tissue containing the seeds and placentae. Mean PA polymer length was seven to 8.5 subunits, linked predominantly via B-type linkages, and was relatively constant throughout development. Flavonol accumulation and localization patterns were similar to those of the PAs, and the B-ring hydroxylation pattern of both was correlated with flavonoid-3'-hydroxylase transcript abundance. By contrast, anthocyanins accumulated late in maturation, which coincided with a peak in flavonoid-3-O-glycosyltransferase and flavonoid-3'5'-hydroxylase transcripts. Transcripts of VcMYBPA1, which likely encodes an R2R3-MYB transcriptional regulator of PA synthesis, were prominent in both phases of development. Furthermore, the initiation of ripening was accompanied by a substantial rise in abscisic acid, a growth regulator that may be an important component of the ripening process and contribute to the regulation of

  15. Phosphorylation of serine residue modulates cotton Di19-1 and Di19-2 activities for responding to high salinity stress and abscisic acid signaling

    Qin, Li-Xia; Nie, Xiao-Ying; Hu, Rong; Li, Gang; Xu, Wen-Liang; Li, Xue-Bao

    2016-01-01

    Di19 (drought-induced protein 19) family is a novel type of Cys2/His2 zinc-finger proteins. In this study, we demonstrated that cotton Di19-1 and Di19-2 (GhDi19-1/-2) proteins could be phosphorylated in vitro by the calcium-dependent protein kinase (CDPK). Mutation of Ser to Ala in N-terminus of GhDi19-1/-2 led to the altered subcellular localization of the two proteins, but the constitutively activated form (Ser was mutated to Asp) of GhDi19-1/-2 still showed the nuclear localization. GhDi19-1/-2 overexpression transgenic Arabidopsis seedlings displayed the hypersensitivity to high salinity and abscisic acid (ABA). However, Ser site-mutated GhDi19-1(S116A) and GhDi19-2(S114A), and Ser and Thr double sites-mutated GhDi19-1(S/T-A/A) and GhDi19-2(S/T-A/A) transgenic Arabidopsis did not show the salt- and ABA-hypersensitive phenotypes. In contrast, overexpression of Thr site-mutated GhDi19-1(T114A) and GhDi19-2(T112A) in Arabidopsis still resulted in salt- and ABA-hypersensitivity phenotypes, like GhDi19-1/-2 transgenic lines. Overexpression of GhDi19-1/-2 and their constitutively activated forms in Atcpk11 background could recover the salt- and ABA-insensitive phenotype of the mutant. Thus, our results demonstrated that Ser phosphorylation (not Thr phosphorylation) is crucial for functionally activating GhDi19-1/-2 in response to salt stress and ABA signaling during early plant development, and GhDi19-1/-2 proteins may be downstream targets of CDPKs in ABA signal pathway. PMID:26829353

  16. Abscisic Acid Induced Changes in Production of Primary and Secondary Metabolites, Photosynthetic Capacity, Antioxidant Capability, Antioxidant Enzymes and Lipoxygenase Inhibitory Activity of Orthosiphon stamineus Benth.

    Mohd Hafiz Ibrahim

    2013-07-01

    Full Text Available An experiment was conducted to investigate and distinguish the relationships in the production of total phenolics, total flavonoids, soluble sugars, H2O2, O2−, phenylalanine ammonia lyase (PAL activity, leaf gas exchange, antioxidant activity, antioxidant enzyme activity [ascorbate peroxidase (APX, catalase (CAT, superoxide dismutase (SOD and Lipoxygenase inhibitory activity (LOX] under four levels of foliar abscisic acid (ABA application (0, 2, 4, 6 µM for 15 weeks in Orthosiphon stamineus Benth. It was found that the production of plant secondary metabolites, soluble sugars, antioxidant activity, PAL activity and LOX inhibitory activity was influenced by foliar application of ABA. As the concentration of ABA was increased from 0 to 6 µM the production of total phenolics, flavonoids, sucrose, H2O2, O2−, PAL activity and LOX inhibitory activity was enhanced. It was also observed that the antioxidant capabilities (DPPH and ORAC were increased. This was followed by increases in production of antioxidant enzymes APX, CAT and SOD. Under high application rates of ABA the net photosynthesis and stomatal conductance was found to be reduced. The production of primary and secondary metabolites displayed a significant positive relationship with H2O2 (total phenolics, r2 = 0.877; total flavonoids, r2 = 0.812; p ≤ 0.05 and O2− (total phenolics, r2 = 0.778; total flavonoids, r2 = 0.912; p ≤ 0.05. This indicated that increased oxidative stress at high application rates of ABA, improved the production of phytochemicals.

  17. The APETALA-2-like transcription factor OsAP2-39 controls key interactions between abscisic acid and gibberellin in rice.

    Mahmoud W Yaish

    2010-09-01

    Full Text Available The interaction between phytohormones is an important mechanism which controls growth and developmental processes in plants. Deciphering these interactions is a crucial step in helping to develop crops with enhanced yield and resistance to environmental stresses. Controlling the expression level of OsAP2-39 which includes an APETALA 2 (AP2 domain leads to phenotypic changes in rice. Overexpression of OsAP2-39 leads to a reduction in yield by decreasing the biomass and the number of seeds in the transgenic rice lines. Global transcriptome analysis of the OsAP2-39 overexpression transgenic rice revealed the upregulation of a key abscisic acid (ABA biosynthetic gene OsNCED-I which codes for 9-cis-epoxycarotenoid dioxygenase and leads to an increase in the endogenous ABA level. In addition to OsNCED-1, the gene expression analysis revealed the upregulation of a gene that codes for the Elongation of Upper most Internode (EUI protein, an enzyme that catalyzes 16α, 17-epoxidation of non-13-hydroxylated GAs, which has been shown to deactivate gibberellins (GAs in rice. The exogenous application of GA restores the wild-type phenotype in the transgenic line and ABA application induces the expression of EUI and suppresses the expression of OsAP2-39 in the wild-type line. These observations clarify the antagonistic relationship between ABA and GA and illustrate a mechanism that leads to homeostasis of these hormones. In vivo and in vitro analysis showed that the expression of both OsNCED-1 and EUI are directly controlled by OsAP2-39. Together, these results reveal a novel mechanism for the control of the ABA/GA balance in rice which is regulated by OsAP2-39 that in turn regulates plant growth and seed production.

  18. Increased abscisic acid levels in transgenic maize overexpressing AtLOS5 mediated root ion fluxes and leaf water status under salt stress.

    Zhang, Juan; Yu, Haiyue; Zhang, Yushi; Wang, Yubing; Li, Maoying; Zhang, Jiachang; Duan, Liusheng; Zhang, Mingcai; Li, Zhaohu

    2016-03-01

    Abscisic acid (ABA) is a vital cellular signal in plants, and effective ABA signalling is pivotal for stress tolerance. AtLOS5 encoding molybdenum cofactor sulphurase is a key regulator of ABA biosynthesis. Here, transgenic AtLOS5 plants were generated to explore the role of AtLOS5 in salt tolerance in maize. AtLOS5 overexpression significantly up-regulated the expression of ZmVp14-2, ZmAO, and ZmMOCO, and increased aldehyde oxidase activities, which enhanced ABA accumulation in transgenic plants under salt stress. Concurrently, AtLOS5 overexpression induced the expression of ZmNHX1, ZmCBL4, and ZmCIPK16, and enhanced the root net Na(+) efflux and H(+) influx, but decreased net K(+) efflux, which maintained a high cytosolic K(+)/Na(+) ratio in transgenic plants under salt stress. However, amiloride or sodium orthovanadate could significantly elevate K(+) effluxes and decrease Na(+) efflux and H(+) influx in salt-treated transgenic roots, but the K(+) effluxes were inhibited by TEA, suggesting that ion fluxes regulated by AtLOS5 overexpression were possibly due to activation of Na(+)/H(+) antiport and K(+) channels across the plasma membrane. Moreover, AtLOS5 overexpression could up-regulate the transcripts of ZmPIP1:1, ZmPIP1:5, and ZmPIP2:4, and enhance root hydraulic conductivity. Thus transgenic plants had higher leaf water potential and turgor, which was correlated with greater biomass accumulation under salt stress. Thus AtLOS5 overexpression induced the expression of ABA biosynthetic genes to promote ABA accumulation, which activated ion transporter and PIP aquaporin gene expression to regulate root ion fluxes and water uptake, thus maintaining high cytosolic K(+) and Na(+) homeostasis and better water status in maize exposed to salt stress. PMID:26743432

  19. Release of GTP Exchange Factor Mediated Down-Regulation of Abscisic Acid Signal Transduction through ABA-Induced Rapid Degradation of RopGEFs

    Waadt, Rainer; Schroeder, Julian I.

    2016-01-01

    The phytohormone abscisic acid (ABA) is critical to plant development and stress responses. Abiotic stress triggers an ABA signal transduction cascade, which is comprised of the core components PYL/RCAR ABA receptors, PP2C-type protein phosphatases, and protein kinases. Small GTPases of the ROP/RAC family act as negative regulators of ABA signal transduction. However, the mechanisms by which ABA controls the behavior of ROP/RACs have remained unclear. Here, we show that an Arabidopsis guanine nucleotide exchange factor protein RopGEF1 is rapidly sequestered to intracellular particles in response to ABA. GFP-RopGEF1 is sequestered via the endosome-prevacuolar compartment pathway and is degraded. RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1. Interestingly, RopGEF1 undergoes constitutive degradation in pp2c quadruple abi1/abi2/hab1/pp2ca mutant plants, revealing that active PP2C protein phosphatases protect and stabilize RopGEF1 from ABA-mediated degradation. Interestingly, ABA-mediated degradation of RopGEF1 also plays an important role in ABA-mediated inhibition of lateral root growth. The presented findings point to a PP2C-RopGEF-ROP/RAC control loop model that is proposed to aid in shutting off ABA signal transduction, to counteract leaky ABA signal transduction caused by “monomeric” PYL/RCAR ABA receptors in the absence of stress, and facilitate signaling in response to ABA. PMID:27192441

  20. The upregulation of thiamine (vitamin B1 biosynthesis in Arabidopsis thaliana seedlings under salt and osmotic stress conditions is mediated by abscisic acid at the early stages of this stress response

    Rapala-Kozik Maria

    2012-01-01

    Full Text Available Abstract Background Recent reports suggest that vitamin B1 (thiamine participates in the processes underlying plant adaptations to certain types of abiotic and biotic stress, mainly oxidative stress. Most of the genes coding for enzymes involved in thiamine biosynthesis in Arabidopsis thaliana have been identified. In our present study, we examined the expression of thiamine biosynthetic genes, of genes encoding thiamine diphosphate-dependent enzymes and the levels of thiamine compounds during the early (sensing and late (adaptation responses of Arabidopsis seedlings to oxidative, salinity and osmotic stress. The possible roles of plant hormones in the regulation of the thiamine contribution to stress responses were also explored. Results The expression of Arabidopsis genes involved in the thiamine diphosphate biosynthesis pathway, including that of THI1, THIC, TH1 and TPK, was analyzed for 48 h in seedlings subjected to NaCl or sorbitol treatment. These genes were found to be predominantly up-regulated in the early phase (2-6 h of the stress response. The changes in these gene transcript levels were further found to correlate with increases in thiamine and its diphosphate ester content in seedlings, as well as with the enhancement of gene expression for enzymes which require thiamine diphosphate as a cofactor, mainly α-ketoglutarate dehydrogenase, pyruvate dehydrogenase and transketolase. In the case of the phytohormones including the salicylic, jasmonic and abscisic acids which are known to be involved in plant stress responses, only abscisic acid was found to significantly influence the expression of thiamine biosynthetic genes, the thiamine diphosphate levels, as well as the expression of genes coding for main thiamine diphosphate-dependent enzymes. Using Arabidopsis mutant plants defective in abscisic acid production, we demonstrate that this phytohormone is important in the regulation of THI1 and THIC gene expression during salt stress

  1. AtPP2CG1, a protein phosphatase 2C, positively regulates salt tolerance of Arabidopsis in abscisic acid-dependent manner

    Liu, Xin, E-mail: fangfei6073@126.com [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Zhu, Yanming, E-mail: ymzhu2001@neau.edu.cn [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Zhai, Hong, E-mail: Zhai.h@neigaehrb.ac.cn [Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150040 (China); Cai, Hua, E-mail: small-big@sohu.com [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Ji, Wei, E-mail: iwei_j@hotmail.com [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Luo, Xiao, E-mail: luoxiao2010@yahoo.cn [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Li, Jing, E-mail: lijing@neau.edu.cn [Plant Secondary Metabolism Laboratory, Northeast Agricultural University, Harbin 150030 (China); Bai, Xi, E-mail: baixi@neau.edu.cn [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer AtPP2CG1 positively regulates salt tolerance in ABA-dependent manner. Black-Right-Pointing-Pointer AtPP2CG1 up-regulates the expression of marker genes in different pathways. Black-Right-Pointing-Pointer AtPP2CG1 expresses in the vascular system and trichomes of Arabidopsis. -- Abstract: AtPP2CG1 (Arabidopsis thaliana protein phosphatase 2C G Group 1) was predicted as an abiotic stress candidate gene by bioinformatic analysis in our previous study. The gene encodes a putative protein phosphatase 2C that belongs to Group G of PP2C. There is no report of Group G genes involved in abiotic stress so far. Real-time RT-PCR analysis showed that AtPP2CG1 expression was induced by salt, drought, and abscisic acid (ABA) treatment. The expression levels of AtPP2CG1 in the ABA synthesis-deficient mutant abi2-3 were much lower than that in WT plants under salt stress suggesting that the expression of AtPP2CG1 acts in an ABA-dependent manner. Over-expression of AtPP2CG1 led to enhanced salt tolerance, whereas its loss of function caused decreased salt tolerance. These results indicate that AtPP2CG1 positively regulates salt stress in an ABA-dependent manner. Under salt treatment, AtPP2CG1 up-regulated the expression levels of stress-responsive genes, including RD29A, RD29B, DREB2A and KIN1. GUS activity was detected in roots, leaves, stems, flower, and trichomes of AtPP2CG1 promoter-GUS transgenic plants. AtPP2CG1 protein was localized in nucleus and cytoplasm via AtPP2CG1:eGFP and YFP:AtPP2CG1 fusion approaches.

  2. ORA47 (octadecanoid-responsive AP2/ERF-domain transcription factor 47) regulates jasmonic acid and abscisic acid biosynthesis and signaling through binding to a novel cis-element.

    Chen, Hsing-Yu; Hsieh, En-Jung; Cheng, Mei-Chun; Chen, Chien-Yu; Hwang, Shih-Ying; Lin, Tsan-Piao

    2016-07-01

    ORA47 (octadecanoid-responsive AP2/ERF-domain transcription factor 47) of Arabidopsis thaliana is an AP2/ERF domain transcription factor that regulates jasmonate (JA) biosynthesis and is induced by methyl JA treatment. The regulatory mechanism of ORA47 remains unclear. ORA47 is shown to bind to the cis-element (NC/GT)CGNCCA, which is referred to as the O-box, in the promoter of ABI2. We proposed that ORA47 acts as a connection between ABA INSENSITIVE1 (ABI1) and ABI2 and mediates an ABI1-ORA47-ABI2 positive feedback loop. PORA47:ORA47-GFP transgenic plants were used in a chromatin immunoprecipitation (ChIP) assay to show that ORA47 participates in the biosynthesis and/or signaling pathways of nine phytohormones. Specifically, many abscisic acid (ABA) and JA biosynthesis and signaling genes were direct targets of ORA47 under stress conditions. The JA content of the P35S:ORA47-GR lines was highly induced under wounding and moderately induced under water stress relative to that of the wild-type plants. The wounding treatment moderately increased ABA accumulation in the transgenic lines, whereas the water stress treatment repressed the ABA content. ORA47 is proposed to play a role in the biosynthesis of JA and ABA and in regulating the biosynthesis and/or signaling of a suite of phytohormone genes when plants are subjected to wounding and water stress. PMID:26974851

  3. Arabidopsis CALCIUM-DEPENDENT PROTEIN KINASE8 and CATALASE3 Function in Abscisic Acid-Mediated Signaling and H2O2 Homeostasis in Stomatal Guard Cells under Drought Stress.

    Zou, Jun-Jie; Li, Xi-Dong; Ratnasekera, Disna; Wang, Cun; Liu, Wen-Xin; Song, Lian-Fen; Zhang, Wen-Zheng; Wu, Wei-Hua

    2015-05-01

    Drought is a major threat to plant growth and crop productivity. Calcium-dependent protein kinases (CDPKs, CPKs) are believed to play important roles in plant responses to drought stress. Here, we report that Arabidopsis thaliana CPK8 functions in abscisic acid (ABA)- and Ca(2+)-mediated plant responses to drought stress. The cpk8 mutant was more sensitive to drought stress than wild-type plants, while the transgenic plants overexpressing CPK8 showed enhanced tolerance to drought stress compared with wild-type plants. ABA-, H2O2-, and Ca(2+)-induced stomatal closing were impaired in cpk8 mutants. Arabidopsis CATALASE3 (CAT3) was identified as a CPK8-interacting protein, confirmed by yeast two-hybrid, coimmunoprecipitation, and bimolecular fluorescence complementation assays. CPK8 can phosphorylate CAT3 at Ser-261 and regulate its activity. Both cpk8 and cat3 plants showed lower catalase activity and higher accumulation of H2O2 compared with wild-type plants. The cat3 mutant displayed a similar drought stress-sensitive phenotype as cpk8 mutant. Moreover, ABA and Ca(2+) inhibition of inward K(+) currents were diminished in guard cells of cpk8 and cat3 mutants. Together, these results demonstrated that CPK8 functions in ABA-mediated stomatal regulation in responses to drought stress through regulation of CAT3 activity. PMID:25966761

  4. Cloning of 9-cis-epoxycarotenoid dioxygenase (NCED) gene encoding a key enzyme during abscisic acid (ABA) biosynthesis and ABA-regulated ethylene production in detached young persimmon calyx

    LENG Ping; ZHANG GuangLian; LI XiangXin; WANG LiangHe; ZHENG ZhongMing

    2009-01-01

    Unlike the typical climacteric fruits,persimmons (Diospyros kaki Thunb.) produce higher levels of ethylene when they are detached from trees at a younger stage.In order to obtain detailed information on the role of abscisic acid (ABA) in ripening,we cloned the DKNCED1,DKACS2,and DKAC01 genes from the calyx.Water loss was first noted in the calyx lobe,and DKNCED1 was highly expressed 1 d after the fruits were detached,coinciding with an increase in the ABA content.Then,the DKACS2 and DKAC01 genes were expressed after some delay.In the calyx,the ABA peak was observed 2 d after the fruits were harvested,and this peak preceded the ethylene peak observed on day 3.The fruit firmness rapidly decreased on day 4,and the fruits softened completely 6 d after they were harvested.The increases in the expressions of ABA,ethylene,and the genes in the calyxes occurred earlier than the corresponding increases in the pulp,although the 3 increases occurred on different days.Exogenous ABA treatment increased ABA concentration,induced expression of both ACS and ACO,and promoted ethylene synthesis and young-fruit softening;by contrast,treatment with NDGA inhibited the gene expressions and ethylene synthesis and delayed young-fruit softening.These results indicate that ethylene biosynthesis in the detached young persimmon fruits is initially triggered by ABA,which is induced by water loss in the calyx,through the induction of DKACS2 and DKAC01 expressions.The ethylene produced in the calyx subsequently diffuses into the pulp tissue,where it induces autocatalytic ethylene biosynthesis,resulting in an abrupt increase in ethylene production.

  5. A link between magnesium-chelatase H subunit and sucrose nonfermenting 1 (SNF1)-related protein kinase SnRK2.6/OST1 in Arabidopsis guard cell signalling in response to abscisic acid.

    Liang, Shan; Lu, Kai; Wu, Zhen; Jiang, Shang-Chuan; Yu, Yong-Tao; Bi, Chao; Xin, Qi; Wang, Xiao-Fang; Zhang, Da-Peng

    2015-10-01

    Magnesium-chelatase H subunit [CHLH/putative abscisic acid (ABA) receptor ABAR] positively regulates guard cell signalling in response to ABA, but the molecular mechanism remains largely unknown. A member of the sucrose nonfermenting 1 (SNF1)-related protein kinase 2 family, SnRK2.6/open stomata 1 (OST1)/SRK2E, which plays a critical role in ABA signalling in Arabidopsis guard cells, interacts with ABAR/CHLH. Neither mutation nor over-expression of the ABAR gene affects significantly ABA-insensitive phenotypes of stomatal movement in the OST1 knockout mutant allele srk2e. However, OST1 over-expression suppresses ABA-insensitive phenotypes of the ABAR mutant allele cch in stomatal movement. These genetic data support that OST1 functions downstream of ABAR in ABA signalling in guard cells. Consistent with this, ABAR protein is phosphorylated, but independently of the OST1 protein kinase. Two ABAR mutant alleles, cch and rtl1, show ABA insensitivity in ABA-induced reactive oxygen species and nitric oxide production, as well as in ABA-activated phosphorylation of a K(+) inward channel KAT1 in guard cells, which is consistent with that observed in the pyr1 pyl1 pyl2 pyl4 quadruple mutant of the well-characterized ABA receptor PYR/PYL/RCAR family acting upstream of OST1. These findings suggest that ABAR shares, at least in part, downstream signalling components with PYR/PYL/RCAR receptors for ABA in guard cells; though cch and rtl1 show strong ABA-insensitive phenotypes in both ABA-induced stomatal closure and inhibition of stomatal opening, while the pyr1 pyl1 pyl2 pyl4 quadruple mutant shows strong ABA insensitivity only in ABA-induced stomatal closure. These data establish a link between ABAR/CHLH and SnRK2.6/OST1 in guard cell signalling in response to ABA. PMID:26175350

  6. The role of abscisic acid in the defence response of tomato (Solanum lycopersicum) to the necrotrophic pathogens Botrytis cinerea and Erwinia chrysanthemi

    Asselbergh, B.

    2007-01-01

    In order to cope with the constant threat of a wide range of potentially harmful micro-organisms, plants have developed an impressive constitutive and inducible defensive machinery of enormous complexity to combat pathogen invasion. Plant hormones are not only important for controlling plant development, but are also essential to regulate plant responses to the environment. The plant hormones salicylic acid (SA), jasmonate (JA) and ethylene (ET) are classically associated with plant pathogen ...

  7. The nitrate transporter MtNPF6.8 (MtNRT1.3) transports abscisic acid and mediates nitrate regulation of primary root growth in Medicago truncatula.

    Pellizzaro, Anthoni; Clochard, Thibault; Cukier, Caroline; Bourdin, Céline; Juchaux, Marjorie; Montrichard, Françoise; Thany, Steeve; Raymond, Valérie; Planchet, Elisabeth; Limami, Anis M; Morère-Le Paven, Marie-Christine

    2014-12-01

    Elongation of the primary root during postgermination of Medicago truncatula seedlings is a multigenic trait that is responsive to exogenous nitrate. A quantitative genetic approach suggested the involvement of the nitrate transporter MtNPF6.8 (for Medicago truncatula NITRATE TRANSPORTER1/PEPTIDE TRANSPORTER Family6.8) in the inhibition of primary root elongation by high exogenous nitrate. In this study, the inhibitory effect of nitrate on primary root elongation, via inhibition of elongation of root cortical cells, was abolished in npf6.8 knockdown lines. Accordingly, we propose that MtNPF6.8 mediates nitrate inhibitory effects on primary root growth in M. truncatula. pMtNPF6.8:GUS promoter-reporter gene fusion in Agrobacterium rhizogenes-generated transgenic roots showed the expression of MtNPF6.8 in the pericycle region of primary roots and lateral roots, and in lateral root primordia and tips. MtNPF6.8 expression was insensitive to auxin and was stimulated by abscisic acid (ABA), which restored the inhibitory effect of nitrate in npf6.8 knockdown lines. It is then proposed that ABA acts downstream of MtNPF6.8 in this nitrate signaling pathway. Furthermore, MtNPF6.8 was shown to transport ABA in Xenopus spp. oocytes, suggesting an additional role of MtNPF6.8 in ABA root-to-shoot translocation. (15)NO3(-)-influx experiments showed that only the inducible component of the low-affinity transport system was affected in npf6.8 knockdown lines. This indicates that MtNPF6.8 is a major contributor to the inducible component of the low-affinity transport system. The short-term induction by nitrate of the expression of Nitrate Reductase1 (NR1) and NR2 (genes that encode two nitrate reductase isoforms) was greatly reduced in the npf6.8 knockdown lines, supporting a role of MtNPF6.8 in the primary nitrate response in M. truncatula. PMID:25367858

  8. EL ÁCIDO ABSCÍSICO ACELERA EL DESARROLLO FLORAL DE SOLIDAGO EN DÍAS CORTOS ABSCISIC ACID SPEED UP FLORAL DEVELOPMENT OF SOLIDAGO UNDER SHORT DAYS

    Víctor Julio Flórez Roncancio

    2009-06-01

    Full Text Available Solidago x luteus (M. L. Greene Broulliet y Semple (= x Solidaster hybridus, x S. luteus es una planta que responde a días cortos (DC para el desarrollo floral. En este proceso se ha establecido la participación de varias fitohormonas, entre éstas, la presencia del ácido abscísico (ABA en zonas y periodos específicos durante el desarrollo de la flor lo cual sugiere su acción promotora en la velocidad de antesis floral de esta especie en DC. En este trabajo se buscaron nuevos indicios de la participación de fitohormonas presentes en la fracción ácida con el proceso de floración. En una primera etapa, extractos foliares provenientes de hojas de plantas en días largos (caracterizadas por menor velocidad de antesis floral se aplicaron en botones florales de plantas en días cortos (caracterizadas por una mayor velocidad de antesis floral. Se realizaron ocho aplicaciones con diferentes frecuencias totalizando un periodo de tratamiento de 25 días. Los resultados mostraron que las sustancias presentes en los extractos de la fracción ácida, no alteran la velocidad promedio de antesis floral en los botones florales de plantas en DC. En la segunda etapa del experimento, la cuantificación de los extractos por ELISA, permitió establecer una mayor concentración de ABA en los extractos de hojas y de botones florales de plantas en DC y de botones florales en el inicio del tratamiento. Estos resultados confirman la relación del ABA con la mayor velocidad de antesis floral en plantas de Solidago x luteus en condiciones de DC.Solidago x luteus (M.L. Greene Broulliet & Semple (= x Solidaster hybridus, x S. luteus is a plant that respond to short days (SD for flower development. In this process, there has been established the involvement of many phytohormones, between these, the presence of the abscisic acid (ABA in zones and specific periods during flower development, suggests its promoter roll on the floral anthesis period of this species under

  9. 枸杞脱落酸生物合成关键酶基因NCED的克隆及表达分析%Cloning and Characterization of 9-cis-epoxycarotenoid Dioxygenase Gene(NCED) Encoding a Key Enzyme during Abscisic Acid Biosynthesis in Lycium barbarum L.

    陆平; 田跃胜; 王名雪; 李杉; 赵静雅

    2013-01-01

    Abscisic acid(ABA) regulates the essential physiological and developmental processes of plants and plays imporant roles in plant responses to various environmental stresses. 9-cis-epoxycarotenoid dioxygenase ( NCED)is the key regulatory enzyme in the biosynthesis pathway of ABA in higher plants. In the study,a full-lengh cDNA of NCED gene( LbNCED) was fristly isolated and characterized from the leaves of L. barbarum. LbNCED was 2316 bp, containing a 1824 bp ORF and encoding 607 amino acids. Comparative and bioinformatics analysis revealed that the homology amino acid sequence of Lycopersicon esculentum and Solarium tuberosum LbNCED was 90%. At the N-terminus of the LbNCED located a 15 amino acids putative chloroplast transit peptide. Southern blot analysis revealed that it was a low-copy gene in the genome of L. barbarum. Real-time Quantitative PCR ( RT-QPCR) analysis showed that LbNCED mRNA most abundantly accumulated in leaves. The RT-QPCR analysis revealed that dehydration and salt stress signficantly enhanced LbNCED transcript expression and ABA content accumulation.%脱落酸(abscisic acid,ABA)对植物的生长发育具有独特的调控功能,并在植物适应逆境环境中发挥重要作用.9-顺式环氧类胡萝卜素双加氧酶(NCED)是高等植物中ABA生物合成途径的一个关键酶.根据GenBank中的植物NCED基因的同源序列设计简并引物,通过RT-PCR及RACE技术从枸杞叶片中克隆到1个编码NCED的基因,命名为LbNCED.其cDNA全长为2316 bp,含有1个1824 bp的开放阅读框,编码1个含607氨基酸残基,分子量为67.38 kDa、等电点(pI)为6.43的假定蛋白,其氨基酸序列与番茄(Lycopersicon esculentum)和马铃薯(Solanum tuberosum)的同源性达90%,在N-末端具有1个含15个氨基酸的叶绿体转运肽.Southern杂交结果表明,该基因在枸杞基因组中以低拷贝形式存在.盐处理和脱水处理的枸杞叶片中LbNCED基因的表达与内源ABA的积累同步变化.

  10. A transcript profiling approach reveals an abscisic acid-specific glycosyltransferase (UGT73C14 induced in developing fiber of Ligon lintless-2 mutant of cotton (Gossypium hirsutum L..

    Matthew K Gilbert

    Full Text Available Ligon lintless-2, a monogenic dominant cotton (Gossypium hirsutum L. fiber mutation, causing extreme reduction in lint fiber length with no pleiotropic effects on vegetative growth, represents an excellent model system to study fiber elongation. A UDP-glycosyltransferase that was highly expressed in developing fibers of the mutant Ligon lintless-2 was isolated. The predicted amino acid sequence showed ~53% similarity with Arabidopsis UGT73C sub-family members and the UDP-glycosyltransferase was designated as UGT73C14. When expressed in Escherichia coli as a recombinant protein with a maltose binding protein tag, UGT73C14 displayed enzymatic activity toward ABA and utilized UDP-glucose and UDP-galactose as the sugar donors. The recombinant UGT73C14 converted natural occurring isoform (+-cis, trans-ABA better than (+-trans, trans-ABA and (--cis, trans-ABA. Transgenic Arabidopsis plants constitutively overexpressing UGT73C14 did not show phenotypic changes under standard growth conditions. However, the increased glycosylation of ABA resulted in phenotypic changes in post-germinative growth and seedling establishment, confirming in vivo activity of UGT73C14 for ABA. This suggests that the expression level of UGT73C14 is regulated by the observed elevated levels of ABA in developing fibers of the Li 2 mutant line and may be involved in the regulation of ABA homeostasis.