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Sample records for abscisic acid electronic

  1. Relationship between abscisic acid (ABA) concentration and some ...

    African Journals Online (AJOL)

    saeed

    2011-11-16

    Nov 16, 2011 ... This work investigated the effects of endogenous abscisic acid (ABA) and physiologic parameters related to yield in two ... levels of endogenous ABA contribute to reduced grain growth. Key words: Abscisic acid, ..... Craterostigma plantagineum displays no defined three dimensional structure in its native ...

  2. Interactions between ethylene, abscisic acid and cytokinin during ...

    Indian Academy of Sciences (India)

    Interactions between ethylene, abscisic acid and cytokinin during germination and seedling establishment in Arabidopsis. VEERAPUTHIRAN SUBBIAH and KARINGU JANARDHAN REDDY. J. Biosci. 35(3), September 2010, 451–459 © Indian Academy of Sciences. Supplementary figure. Supplementary figure 1.

  3. Cis-trans photoisomerization of abscisic acid

    International Nuclear Information System (INIS)

    Brabham, D.E.; Biggs, R.H.

    1981-01-01

    An important regulator of numerous physiological processes in higher plants is abscisic acid (ABA), which is photoisomerized from the more biologically active cis isomer to the nearly inactive trans isomer by natural sunlight. It is possible that this photoisomerization is a UV control mechanism in functions regulated by ABA. The quantum yields of both the cis to trans and trans to cis photoisomerizations were measured under various conditions of pH and oxygen concentration at room temperature. The yield for photoisomerization of cis-ABA ranged from 0.25 at pH 3.0 to 0.11 at pH 7.0. Oxygen partially quenched the process. The quantum yield varied only slightly with wavelength. The quantum yield of photolysis of cis-ABA was reported for pH 3.0 as 0.06. This yield also varied slightly with wavelength and was relatively insensitive to oxygen. This relatively high yield explains the loss of potency of ABA during UV irradiation. Phosphorescence of cis- and trans-ABA was observed in methanol at 77 K. Onset of the emission was at 350 nm. The emission spectra were the same for both isomers. From these results a mechanism of UV action on plants based on the photoisomerization of the inactive trans-ABA to the biologically active cis isomer is proposed. (author)

  4. GENETIC ANALYSIS OF ABSCISIC ACID BIOSYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    Creelman, R.A.; Zeevaart, J.A.D.

    1984-01-01

    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% 18 O 2 and 80% N 2 indicates that one atom of 18 O 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 18 O 2 indicates that one atom of 18 O 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

  6. Effect of activated charcoal, abscisic acid and polyethylene glycol on ...

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... The influence of activated charcoal (AC), abscisic acid (ABA) and polyethylene glycol (PEG) on the maturation and conversion of horse chestnut (Aesculus hippocastanum L.) androgenic embryos were tested. Androgenic embryos originating from microspores and anther culture were maturated over 90.

  7. Abscisic acid and assimilate partitioning during seed development

    NARCIS (Netherlands)

    Bruijn, de S.M.

    1993-01-01

    This thesis describes the influence of abscisic acid (ABA) on the transport of assimilates to seeds and the deposition of reserves in seeds. It is well-known from literature that ABA accumulates in seeds during development, and that ABA concentrations in seeds correlate rather well with

  8. Relationship between abscisic acid (ABA) concentration and some ...

    African Journals Online (AJOL)

    This work investigated the effects of endogenous abscisic acid (ABA) and physiologic parameters related to yield in two wheat cultivars (Triticum aestivum L.), Marvdasht and Zagros (sensitive and tolerant to terminal season drought, respectively) grown in pots under well watered and water-stressed starting from anthesis ...

  9. Abscisic acid represses the transcription of chloroplast genes

    Czech Academy of Sciences Publication Activity Database

    Yamburenko, M.V.; Zubo, Y.O.; Vaňková, Radomíra; Kusnetsov, V.; Kulaeva, O.N.; Borner, T.

    2013-01-01

    Roč. 64, č. 14 (2013), s. 4491-4502 ISSN 0022-0957 R&D Projects: GA ČR GA522/09/2058 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid (ABA) * chloroplast * cytokinin Subject RIV: ED - Physiology Impact factor: 5.794, year: 2013

  10. [Tissue culture of medicinal plant and abscisic acid].

    Science.gov (United States)

    Fang, Hui-Yong; Zhu, Hong; Yao, Jian-Xun; Jia, Cai-Feng; Shan, Gao-Wei; Li, Min-Hui

    2013-01-01

    Abscisic acid (ABA) plays a key role in many physiological processes of plants, and it was also applied to fields of medicinal plant biotechnology. The article presents a review of some recent application of ABA in enhancing the production of secondary metabolites of medicinal plants, improving the in vitro conservation in medicinal plant tissue culture system.

  11. Effect of activated charcoal, abscisic acid and polyethylene glycol on ...

    African Journals Online (AJOL)

    Effect of activated charcoal, abscisic acid and polyethylene glycol on maturation, germination and conversion of Aesculus hippocastanum androgenic embryos. ... rapid development of embryos in the cotyledonary stage and lowered percentage of abnormal structures. The best results of androgenic microspore embryo ...

  12. Mitogen-activated protein kinase and abscisic acid signal transduction

    NARCIS (Netherlands)

    Heimovaara-Dijkstra, S.; Testerink, C.; Wang, M.

    1998-01-01

    The phytohormone abscisic acid (ABA) is a classical plant hormone, responsible for regulation of abscission, diverse aspects of plant and seed development, stress responses and germination. It was found that ABA signal transduction in plants can involve the activity of type 2C-phosphatases (PP2C),

  13. ABSCISIC ACID EFFECTS ON WATER AND PHOTOSYNTHETIC ...

    African Journals Online (AJOL)

    Bidai Y, Achour A and Belkhodja M

    1 mai 2016 ... diverses notamment hydrique et physiologique chez de nombreuses espèces sous l'action de facteurs hormonaux comme l'acide abscissique (ABA) [7, 8]. En effet, diverses contraintes induisent la synthèse de l'ABA, considéré aujourd'hui comme une hormone de stress [9,. 10,11]. Lors d'un stress ...

  14. ABSCISIC ACID EFFECTS ON WATER AND PHOTOSYNTHETIC ...

    African Journals Online (AJOL)

    Bidai Y, Achour A and Belkhodja M

    1 mai 2016 ... signifie que l'acide abscissique a un effet sur les mouvements sto de ce caractère reste fortement influencée par la variabilité génotypi ..... [17] Paul R., Impens R. Les maladies non parasitaires, In: P. Lepoivre (Ed.), Phytopathologie: Bases moléculaires et biologiques des pathosystèmes et fondements des ...

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

    DEFF Research Database (Denmark)

    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...

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

    DEFF Research Database (Denmark)

    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...... velocity or the uptake. No effect on acropetal transport was observed. The data have been used to discuss the similarities in effects of abscisic acid and visible radiation and a hypothesis is proposed to explain the phenomena of phototropism....

  17. Arabidopsis YAK1 regulates abscisic acid response and drought resistance

    KAUST Repository

    Kim, Dongjin

    2016-06-06

    Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. © 2016 Federation of European Biochemical Societies.

  18. Abscisic acid biosynthesis in water-stressed leaves

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi.

    1989-01-01

    Although abscisic acid (ABA) was discovered 30 years ago, very little is known about its biosynthetic pathway in higher plants. Two hypotheses have been proposed: (i) a direct pathway involving only C-15 intermediates like farnesyl pyrophosphate, (ii) an indirect pathway involving C-40 intermediates like the xanthophylls. When {sup 14}CO{sub 2} was fed into greened bean plants, the {sup 14}C specific activity of ABA was always lower than those in xanthophylls, such as violaxanthin and lutein, regardless of {sup 12}CO{sub 2} chase periods. The ABA accumulation in green leaves was not affected by fluridone when plants were stressed once, but the {sup 14}C incorporation into ABA was inhibited to the same extent as those of xanthophylls. The incorporation of {sup 18}O into the ABA ring when violaxanthin was labeled by {sup 18}O in vivo via the violaxanthin cycle indicates that at least a portion of ABA was derived from {sup 18}O-labeled violaxanthin during water stress.

  19. Plants, endosymbionts and parasites: Abscisic acid and calcium signaling.

    Science.gov (United States)

    Nagamune, Kisaburo; Xiong, Liming; Chini, Eduardo; Sibley, L David

    2008-01-01

    It was recently discovered that the protozoan parasite, Toxoplasma gondii produces and uses the plant hormone, abscisic acid (ABA), for communication. Following intracellular replication, ABA production influences the timing of parasite egress from the host cell. This density-dependent signal may serve to coordinate exit from the host cell in a synchronous manner by triggering calcium-dependent activation of motility. In the absence of ABA production, parasites undergo differentiation to the semidormant, tissue cyst. The pathway for ABA production in T. gondii may be derived from a relict endosymbiont, acquired by ingestion of a red algal cell. Although the parasite has lost the capacity for photosynthesis, the plant-like nature of this signaling pathway may be exploited to develop new drugs. In support of this idea, an inhibitor of ABA biosynthesis protected mice against lethal infection with T. gondii. Here, we compare the role of ABA in parasites to its activities in plants, where it is know to control development and stress responses.

  20. Transcriptome profiling during mangrove viviparity in response to abscisic acid.

    Science.gov (United States)

    Hong, Liwei; Su, Wenyue; Zhang, Yuanye; Ye, Congting; Shen, Yingjia; Li, Qingshun Q

    2018-01-15

    Mangrove plants adapt to coastal tidal mudflats with specially evolved viviparity seed development. However, very little is known about the genetic and molecular mechanisms of mangrove viviparity. Here, we tested a hypothesis that plant hormone abscisic acid (ABA) plays a significant role in precocious germination of viviparous Kandelia obovata seeds by exogenous applications. Through transcriptome analysis of ABA treated seeds, it was found that ABA repressed mangrove fruit growth and development, and there were thousands of genes differentially expressed. As a result, dynamics of the pathways were dramatically altered. In particular, "Plant hormone signal transduction" and "MAPK signaling pathway" were represented significantly. Among differentially expressed genes, some key genes of ABA signal transduction were induced, while ABA biosynthesis genes were repressed. Take ABI1 and ABI2, key negative regulators in ABA signal pathway, as examples, homologous alignment and a phylogenetic tree in various species showed that ABI1 and ABI2 are highly conserved among various species. The functional similarity of these genes was confirmed by transgenic work in Arabidopsis. Taken together, ABA inhibited mangrove viviparity, but mangroves developed a mechanism to prevent accidently increase of ABA in the harsh environment for maintaining viviparous reproductive strategy.

  1. Abscisic acid enhances cold tolerance in honeybee larvae.

    Science.gov (United States)

    Ramirez, Leonor; Negri, Pedro; Sturla, Laura; Guida, Lucrezia; Vigliarolo, Tiziana; Maggi, Matías; Eguaras, Martín; Zocchi, Elena; Lamattina, Lorenzo

    2017-04-12

    The natural composition of nutrients present in food is a key factor determining the immune function and stress responses in the honeybee ( Apis mellifera ). We previously demonstrated that a supplement of abscisic acid (ABA), a natural component of nectar, pollen, and honey, increases honeybee colony survival overwinter. Here we further explored the role of ABA in in vitro -reared larvae exposed to low temperatures. Four-day-old larvae (L4) exposed to 25°C for 3 days showed lower survival rates and delayed development compared to individuals growing at a standard temperature (34°C). Cold-stressed larvae maintained higher levels of ABA for longer than do larvae reared at 34°C, suggesting a biological significance for ABA. Larvae fed with an ABA-supplemented diet completely prevent the low survival rate due to cold stress and accelerate adult emergence. ABA modulates the expression of genes involved in metabolic adjustments and stress responses: Hexamerin 70b, Insulin Receptor Substrate, Vitellogenin , and Heat Shock Proteins 70. AmLANCL2, the honeybee ABA receptor, is also regulated by cold stress and ABA. These results support a role for ABA increasing the tolerance of honeybee larvae to low temperatures through priming effects. © 2017 The Author(s).

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

    International Nuclear Information System (INIS)

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

    1986-01-01

    The compartmentation of endogenous abscisic acid (ABA), applied (+/-)-[ 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 (+/-)-[ 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 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

  3. Abscisic acid controlled sex before transpiration in vascular plants.

    Science.gov (United States)

    McAdam, Scott A M; Brodribb, Timothy J; Banks, Jo Ann; Hedrich, Rainer; Atallah, Nadia M; Cai, Chao; Geringer, Michael A; Lind, Christof; Nichols, David S; Stachowski, Kye; Geiger, Dietmar; Sussmilch, Frances C

    2016-10-26

    Sexual reproduction in animals and plants shares common elements, including sperm and egg production, but unlike animals, little is known about the regulatory pathways that determine the sex of plants. Here we use mutants and gene silencing in a fern species to identify a core regulatory mechanism in plant sexual differentiation. A key player in fern sex differentiation is the phytohormone abscisic acid (ABA), which regulates the sex ratio of male to hermaphrodite tissues during the reproductive cycle. Our analysis shows that in the fern Ceratopteris richardii, a gene homologous to core ABA transduction genes in flowering plants [SNF1-related kinase2s (SnRK2s)] is primarily responsible for the hormonal control of sex determination. Furthermore, we provide evidence that this ABA-SnRK2 signaling pathway has transitioned from determining the sex of ferns to controlling seed dormancy in the earliest seed plants before being co-opted to control transpiration and CO 2 exchange in derived seed plants. By tracing the evolutionary history of this ABA signaling pathway from plant reproduction through to its role in the global regulation of plant-atmosphere gas exchange during the last 450 million years, we highlight the extraordinary effect of the ABA-SnRK2 signaling pathway in plant evolution and vegetation function.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Involvement of abscisic acid in correlative control of flower abscission in soybean

    International Nuclear Information System (INIS)

    Yarrow, G.L.

    1985-01-01

    Studies were carried out in three parts: (1) analysis of endogenous abscisic acid (ABA) in abscising and non-abscising flowers, (2) partitioning of radio-labelled ABA and photoassimilates within the soybean raceme, and (3) shading experiments, wherein endogenous levels, metabolism and partitioning of ABA were determined. Endogenous concentrations of ABA failed to show any consistent relationship to abscission of soybean flowers. Partitioning of radiolabelled ABA and photoassimilates displayed consistently higher sink strengths (% DPM) for both 3 H-ABA and 14 C-photoassimilates for non-abscising flowers than for abscising flowers within control racemes. Shading flowers with aluminum foil, 48 hrs prior to sampling, resulted in lowered endogenous ABA concentrations at 12, 17 and 22 days after anthesis (DAA), but not at 0 or 4 DAA. No differences were found in the catabolism of 3 H-ABA between shaded (abscising) and non-shaded (non-abscising) flowers. Reduced partitioning of ABA and photoassimilates to shaded flowers resulted when shades were applied at 0, 4, 12, and 17 DAA, but not at 22 DAA

  6. Overexpression of Poplar Pyrabactin Resistance-Like Abscisic Acid Receptors Promotes Abscisic Acid Sensitivity and Drought Resistance in Transgenic Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Jingling Yu

    Full Text Available Drought stress is an important environmental factor limiting productivity of plants, especially fast growing species with high water consumption like poplar. Abscisic acid (ABA is a phytohormone that positively regulates seed dormancy and drought resistance. The PYR1 (Pyrabactin Resistance 1/ PYRL (PYR-Like/ RCAR (Regulatory Component of ABA Receptor (PYR/PYL/RCAR ABA receptor family has been identified and widely characterized in Arabidopsis thaliana. However, their functions in poplars remain unknown. Here, we report that 2 of 14 PYR/PYL/RCAR orthologues in poplar (Populus trichocarpa (PtPYRLs function as a positive regulator of the ABA signal transduction pathway. The Arabidopsis transient expression and yeast two-hybrid assays showed the interaction among PtPYRL1 and PtPYRL5, a clade A protein phosphatase 2C, and a SnRK2, suggesting that a core signalling complex for ABA signaling pathway exists in poplars. Phenotypic analysis of PtPYRL1 and PtPYRL5 transgenic Arabidopsis showed that these two genes positively regulated the ABA responses during the seed germination. More importantly, the overexpression of PtPYRL1 and PtPYRL5 substantially improved ABA sensitivity and drought stress tolerance in transgenic plants. In summary, we comprehensively uncovered the properties of PtPYRL1 and PtPYRL5, which might be good target genes to genetically engineer drought-Resistant plants.

  7. Sinapic acid or its derivatives interfere with abscisic acid homeostasis during Arabidopsis thaliana seed germination.

    Science.gov (United States)

    Bi, Baodi; Tang, Jingliang; Han, Shuang; Guo, Jinggong; Miao, Yuchen

    2017-06-06

    Sinapic acid and its esters have broad functions in different stages of seed germination and plant development and are thought to play a role in protecting against ultraviolet irradiation. To better understand the interactions between sinapic acid esters and seed germination processes in response to various stresses, we analyzed the role of the plant hormone abscisic acid (ABA) in the regulation of sinapic acid esters involved in seed germination and early seedling growth. We found that exogenous sinapic acid promotes seed germination in a dose-dependent manner in Arabidopsis thaliana. High-performance liquid chromatography mass spectrometry analysis showed that exogenous sinapic acid increased the sinapoylcholine content of imbibed seeds. Furthermore, sinapic acid affected ABA catabolism, resulting in reduced ABA levels and increased levels of the ABA-glucose ester. Using mutants deficient in the synthesis of sinapate esters, we showed that the germination of mutant sinapoylglucose accumulator 2 (sng2) and bright trichomes 1 (brt1) seeds was more sensitive to ABA than the wild-type. Moreover, Arabidopsis mutants deficient in either abscisic acid deficient 2 (ABA2) or abscisic acid insensitive 3 (ABI3) displayed increased expression of the sinapoylglucose:choline sinapoyltransferase (SCT) and sinapoylcholine esterase (SCE) genes with sinapic acid treatment. This treatment also affected the accumulation of sinapoylcholine and free choline during seed germination. We demonstrated that sinapoylcholine, which constitutes the major phenolic component in seeds among various minor sinapate esters, affected ABA homeostasis during seed germination and early seedling growth in Arabidopsis. Our findings provide insights into the role of sinapic acid and its esters in regulating ABA-mediated inhibition of Arabidopsis seed germination in response to drought stress.

  8. In vitro reconstitution of an abscisic acid signalling pathway

    KAUST Repository

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Abscisic acid effects on water and photosynthetic characteristics of ...

    African Journals Online (AJOL)

    The aim of this study is to compare the water and photosynthetic characteristics of two xerophilic ecotypes of Atriplex halimus (L.). Seeds collected from two different sites Djelfa and Oran are germinated in controlled greenhouse. After 6 months, the plantlets were treated 21 days with increasing concentrations of abscisic ...

  11. Possible role of volatile Fatty acids and abscisic Acid in the dormancy of oats.

    Science.gov (United States)

    Berrie, A M

    1979-04-01

    Species of Avena differ markedly in their levels of pre- and post-harvest dormancy. These species offer the opportunity of determining if dormancy is related to the endogenous level of growth inhibitor. Germinability in two species of differing levels of dormancy, common oat Avena sativa L., and wild oat Avena fatua L. was assessed as were the contents of abscisic acid and volatile fatty acids of chain length C(6)-C(10). In A. sativa which did not possess postharvest dormancy there was no correlation between germination and inhibitor levels but in A. fatua the relationship between the content of fatty acid and dormancy was good. The loss of these fatty acids in dry storage by evaporation could explain after ripening.

  12. The effect of drought stress and exogenous abscisic acid on growth ...

    African Journals Online (AJOL)

    Jane

    2011-08-17

    Aug 17, 2011 ... Full Length Research Paper. The effect of drought stress and exogenous abscisic acid on growth ... and sedative properties, folk herbal medicines have used it for the treatment of numerous illnesses for centuries ..... Eucalyptus camaldulensis seedlings. Australian J. Plant Physiol. 18: 153-163. Gowing DJ ...

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

    Czech Academy of Sciences Publication Activity Database

    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

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

    Science.gov (United States)

    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 unde...

  15. Abscisic acid and 14-3-3 proteins control K+ channel activity in barley embryonic root

    NARCIS (Netherlands)

    van den Wijngaard, P.W.J.; Sinnige, M.P.; Roobeek, I.; Reumer, C.G.; Mol, J.N.M.; Wang, M.; de Boer, A.H.; Schoonheim, P.J.

    2005-01-01

    Germination of seeds proceeds in general in two phases, an initial imbibition phase and a subsequent growth phase. In grasses like barley, the latter phase is evident as the emergence of the embryonic root (radicle). The hormone abscisic acid (ABA) inhibits germination because it prevents the embryo

  16. Casein kinase 1-Like 3 is required for abscisic acid regulation of ...

    African Journals Online (AJOL)

    Casein kinase 1-Like 3 is required for abscisic acid regulation of seed germination, root growth, and gene expression in Arabidopsis. M Wang, D Yu, X Guo, X Li, J Zhang, L Zhao, H Chang, S Hu, C Zhang, J Shi, X Liu ...

  17. Overexpression of OsWRKY72 gene interferes in the abscisic acid ...

    Indian Academy of Sciences (India)

    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 ...

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

    Czech Academy of Sciences Publication Activity Database

    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

  19. To Stimulate or Inhibit? That Is the Question for the Function of Abscisic Acid

    Czech Academy of Sciences Publication Activity Database

    Humplík, Jan; Bergougnoux, V.; Van Volkenburgh, E.

    2017-01-01

    Roč. 22, č. 10 (2017), s. 830-841 ISSN 1360-1385 R&D Projects: GA MŠk(CZ) LO1204 Grant - others:PPPLZ(CZ) L200381651 Institutional support: RVO:61389030 Keywords : abscisic acid * etiolation * hypocotyl * photomorphogenesis * skotomorphogenesis Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 11.911, year: 2016

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

    Czech Academy of Sciences Publication Activity Database

    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

  1. Biotechnological characteristics of callusogenesis in maize immature embryo culture under the influence of abscisic acid and 6-benzylaminopurine

    Directory of Open Access Journals (Sweden)

    O. E. Abraimova

    2010-02-01

    Full Text Available The effect of abscisic acid and 6-benzylaminopurine on the induction of callus tissue in maize immature embryo culture was studied. For the majority of investigated genotypes abscisic acid stimulated, but 6-benzylaminopurine inhibited the formation of morphogenic calli in induction medium. It was noted that genotype appeared to be an important factor that determined the character of the influence of phytohormonal composition of the medium on the induction of the specific types of calli. Using of 0.04-0.10 mg/l abscisic acid is recommended for biotechnological production of morphogenic callus tissue in dependence of donor plant genotype.

  2. Effect of abscisic acid on the linoleic acid metabolism in developing maize embryos

    Energy Technology Data Exchange (ETDEWEB)

    Abian, J.; Gelpi, E.; Pages, M. (Centro de Investigacion y Desarrollo, Barcelona (Spain))

    1991-04-01

    Partially purified protein extracts from maize (Zea mays L.) embryos, whether treated or not with abscisic acid (ABA), were incubated with linoleic acid (LA) and 1-({sup 14}C)LA. The resulting LA metabolites were monitored by high performance liquid chromatography with a radioactivity detector and identified by gas chromatography-mass spectrometry. {alpha}- and {gamma}-ketol metabolites arising from 9-lipoxygenase activity were the more abundant compounds detected in the incubates, although the corresponding metabolites produced by 13-lipoxygenase were also present in the samples. In addition, a group of stereoisomers originating form two isomeric trihydroxy acids (9,12,13-trihydroxy-10-octadecenoic and 9,10,13-trihydroxy-11-octadecenoic acids) are described. Important variations in the relative proportions of the LA metabolites were observed depending on the embryo developmental stage and on ABA treatment. Two new ABA-induced compounds have been detected. These compounds are present in embryos at all developmental stages, being more abundant in old (60 days) embryos. Furthermore, ABA induction of these compounds is maximum at very young development stages, decreasing as maturation progresses. A tentative structure for these compounds (10-oxo-9,13-dihydroxy-11-octadecenoic acid and 12-oxo-9,13-dihydroxy-10-octadecenoic acid) is also provided. This study revealed an early stage in maize embryogenesis characterized by a higher relative sensitivity to ABA. The physiological importance of ABA on LA metabolism is discussed.

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

    Czech Academy of Sciences Publication Activity Database

    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

  4. Abscisic Acid Levels during Early Seed Development in Sechium edule Sw

    Science.gov (United States)

    Vernieri, Paolo; Perata, Pierdomenico; Lorenzi, Roberto; Ceccarelli, Nello

    1989-01-01

    The time-course growth of single tissues in pollinated and unpollinated ovules of Sechium edule Sw. is described in relation to the endogenous levels of abscisic acid. Quantitation of abscisic acid (ABA) in the minute amounts of material obtained after ovule dissection has been performed by using a highly specific and sensitive solid-phase radioimmunoassay based on a monoclonal antibody raised against free (S)-ABA. While the absolute amount of ABA rises in both types of ovules, only in unpollinated ones does this leads to an increase in the hormone concentration. Infact in pollinated ovules the rapid growth following pollination prevents, through a dilution effect, the increase in ABA concentration. Growth patterns and endogenous ABA levels are similar for integuments and nucellus tissues either in pollinated or unpollinated ovules. It is suggested that the growth inhibition induced by the increase in ABA concentration after anthesis could be counteracted by the pollination triggered fast ovule growth. PMID:16667185

  5. Abscisic Acid Levels during Early Seed Development in Sechium edule Sw.

    Science.gov (United States)

    Vernieri, P; Perata, P; Lorenzi, R; Ceccarelli, N

    1989-12-01

    The time-course growth of single tissues in pollinated and unpollinated ovules of Sechium edule Sw. is described in relation to the endogenous levels of abscisic acid. Quantitation of abscisic acid (ABA) in the minute amounts of material obtained after ovule dissection has been performed by using a highly specific and sensitive solid-phase radioimmunoassay based on a monoclonal antibody raised against free (S)-ABA. While the absolute amount of ABA rises in both types of ovules, only in unpollinated ones does this leads to an increase in the hormone concentration. Infact in pollinated ovules the rapid growth following pollination prevents, through a dilution effect, the increase in ABA concentration. Growth patterns and endogenous ABA levels are similar for integuments and nucellus tissues either in pollinated or unpollinated ovules. It is suggested that the growth inhibition induced by the increase in ABA concentration after anthesis could be counteracted by the pollination triggered fast ovule growth.

  6. Abscisic acid pathway involved in the regulation of watermelon fruit ripening and quality trait evolution

    OpenAIRE

    Wang, Yanping; Guo, Shaogui; Tian, Shouwei; Zhang, Jie; Ren, Yi; Sun, Honghe; Gong, Guoyi; Zhang, Haiying; Xu, Yong

    2017-01-01

    Watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) is a non-climacteric fruit. The modern sweet-dessert watermelon is the result of years of cultivation and selection for fruits with desirable qualities. To date, the mechanisms of watermelon fruit ripening, and the role of abscisic acid (ABA) in this process, has not been well understood. We quantified levels of free and conjugated ABA contents in the fruits of cultivated watermelon (97103; C. lanatus subsp. vulgaris), semi-wild germplas...

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

    Science.gov (United States)

    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.

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

    Czech Academy of Sciences Publication Activity Database

    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

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

    Czech Academy of Sciences Publication Activity Database

    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 - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : Abscisic acid * Agricultural biostimulant * Brassinosteroids Subject RIV: EF - Botanics Impact factor: 2.559, year: 2014

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Effect of abscisic acid on amino acid uptake and efflux in developing soybean seeds

    International Nuclear Information System (INIS)

    Guldan, S.J.; Brun, W.A.

    1987-01-01

    The role of abscisic acid (ABA) in regulating growth of developing soybean [Glycine max (L.) Merr.] seeds is not fully understood. The objectives of this study were to characterize the effect of ABA on the in vitro uptake of asparagine and glutamine by isolated immature cotyledons in three soybean plant introduction (PI) lines with genotypic differences in seed growth rate and final seed weight. Cotyledons were incubated in uptake buffer solutions plus 14 C-asparagine or 14 C-glutamine and treatment concentrations of ABA. The ABA levels in the uptake solutions were 0, 10 -7 , 10 -6 , and 10 -5 M. The uptake rate of glutamine was approximately three times that of asparagine. Among PI lines, the heavy seeded line had a greater rate of asparagine uptake while the light seeded line had a greater rate of glutamine uptake. For asparagine, 10 -6 M ABA depressed uptake compared to the control. For glutamine, ABA enhanced uptake compared to the control at both 10 -6 and 10 -5 M. In an additional experiment, the authors observed no effect of ABA and K on the release of labeled asparagine from excised soybean seed coats. These data indicate that amino acid uptake rates are genotypically dependent and may be influenced by ABA concentration

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Influence of exogenously applied abscisic acid on carotenoid content and water uptake in flowers of the tea plant (Camellia sinensis).

    Science.gov (United States)

    Baldermann, Susanne; Yang, Ziyin; Sakai, Miwa; Fleischmann, Peter; Morita, Akio; Todoroki, Yasushi; Watanabe, Naoharu

    2013-05-01

    Carotenoids are a major class of plant pigments and fulfill many functions in different organisms that either produce or consume them. Although the color of the stamina of tea (Camellia sinensis) flowers is clearly due to the presence of carotenoids, the carotenoid profile and content remain to be discovered. We investigated the carotenoid profile of tea flowers and determined changes in concentrations over the floral development. The flowers contained oxygenated xanthophylls such as neoxanthin, lutein and zeaxanthin, as well as the hydrocarbons β-carotene and α-carotene. Flowers of the tea plant contain to vegetables comparable amounts of carotenoids. The content of 9'-cis-epoxycarotenoids, which serve as abscisic acid precursors, as well as changes in concentration of abscisic acid were studied. The concentrations of carotenoids decreased whereas the abscisic acid content increased over the floral development. Exogenously applied S-abscisic acid affected water uptake, flower opening and carotenoid accumulation. In summary, this paper reports, for the first time, the carotenoid profile and content of tea flowers. The study revealed that carotenoids in tea flowers are an interesting target in respect of possible applications of tea flower extracts as well as biological functions of abscisic acid during floral development. © 2012 Society of Chemical Industry.

  14. The effect of radiation on growth and abscisic acid in wheat seedlings

    International Nuclear Information System (INIS)

    Degani, N.; Itai, C.

    1978-01-01

    Irradiation of dry wheat grains with various doses (10, 30, 70 krads) of gamma rays, increased abscisic acid (ABA) concentrations in roots and leaves of 5 day old seedlings. The ABA concentration was higher in leaves than in roots. Growth inhibition was proportional to irradiation dose and ABA concentration, and roots were more inhibited than leaves. When irradiation (1 and 2 krads) were applied 24 hr after initiation of germination, ABA concentration was higher in roots than in leaves. It is suggested that radiation-induced ABA may upset the hormonal balance during germination, which may affect growth. (author)

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

    International Nuclear Information System (INIS)

    Popova, L.P.; Tsonev, T.D.; Vaklinova, S.G.

    1987-01-01

    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 14 CO 2 into glycolic acid, glycine, and serine, while 14 C 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 CO 2 -compensation point increased 46% and stomatal resistance increased more than twofold over control plants

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

    DEFF Research Database (Denmark)

    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...

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

    Czech Academy of Sciences Publication Activity Database

    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 - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : Abscisic acid * Ammonium * Indole-3-acetic acid Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.390, year: 2015

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Yotsui, Izumi, E-mail: izumi.yotsui@riken.jp [Department of BioScience, Tokyo University of Agriculture 1-1-1 Sakuragaoka, Setagayaku, Tokyo, 156-8502 (Japan); Serada, Satoshi, E-mail: serada@nibiohn.go.jp [Laboratory of Immune Signal, National Institute of Biomedical Innovation, Health and Nutrition, 7-6-8 Saito-Asagi, Ibaraki, Osaka, 567-0085 (Japan); Naka, Tetsuji, E-mail: tnaka@nibiohn.go.jp [Laboratory of Immune Signal, National Institute of Biomedical Innovation, Health and Nutrition, 7-6-8 Saito-Asagi, Ibaraki, Osaka, 567-0085 (Japan); Saruhashi, Masashi, E-mail: s13db001@mail.saitama-u.ac.jp [Department of BioScience, Tokyo University of Agriculture 1-1-1 Sakuragaoka, Setagayaku, Tokyo, 156-8502 (Japan); Taji, Teruaki, E-mail: t3teruak@nodai.ac.jp [Department of BioScience, Tokyo University of Agriculture 1-1-1 Sakuragaoka, Setagayaku, Tokyo, 156-8502 (Japan); Hayashi, Takahisa, E-mail: t4hayash@nodai.ac.jp [Department of BioScience, Tokyo University of Agriculture 1-1-1 Sakuragaoka, Setagayaku, Tokyo, 156-8502 (Japan); Quatrano, Ralph S., E-mail: rsq@wustl.edu [Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130-4899 (United States); Sakata, Yoichi, E-mail: sakata@nodai.ac.jp [Department of BioScience, Tokyo University of Agriculture 1-1-1 Sakuragaoka, Setagayaku, Tokyo, 156-8502 (Japan)

    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

  20. Abscisic Acid and the Maturation of Cacao Embryos in Vitro 1

    Science.gov (United States)

    Pence, Valerie Creaser

    1992-01-01

    Abscisic acid (ABA) was tested for its ability to affect development of immature zygotic embryos of cacao (Theobroma cacao) in vitro, by adding exogenous ABA, fluridone, or mefluidide to cultured embryos. Endogenous ABA levels, measured by enzyme-linked immunosorbent assay, were increased by exogenous ABA or by culture on sucrose increasing to 21%, and were decreased by fluridone and, to a lesser extent, by mefluidide. The effects of these on maturation were measured as effects on anthocyanins, lipids, and fatty acid saturation, all of which increase with maturation of the cacao embryo. Maturation was stimulated by increasing sucrose and, to a lesser degree, the addition of ABA, but decreasing endogenous ABA by treating with fluridone significantly inhibited all maturation parameters. Although desiccation tolerance does not develop in cacao embryos, these results suggest that ABA and sucrose are both needed for the initiation of events associated with maturation in vitro. PMID:16668805

  1. Endogenous cytokinins, auxins and abscisic acid in Ulva fasciata (Chlorophyta) and Dictyota humifusa (Phaeophyta): towards understanding their biosynthesis and homoeostasis

    Czech Academy of Sciences Publication Activity Database

    Stirk, W.A.; Novák, Ondřej; Hradecká, Veronika; Pěnčík, Aleš; Rolčík, Jakub; Strnad, Miroslav; van Staden, J.

    2009-01-01

    Roč. 44, č. 2 (2009), s. 231-240 ISSN 0967-0262 R&D Projects: GA ČR GA206/05/0894 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * auxins * cytokinins Subject RIV: BO - Biophysics Impact factor: 1.556, year: 2009 www.informaworld.com/smpp/content~content=a911046981

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

    Czech Academy of Sciences Publication Activity Database

    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

  3. Hormonal regulation of seed development and germination in tomato : studies on abscisic acid- and gibberellin-deficient mutants

    NARCIS (Netherlands)

    Groot, S.P.C.

    1987-01-01

    The role of endogenous gibberellins (GAs) and abscisic acid (ABA) in seed development and germination of tomato, was studied with the use of GA- and/or ABA-deficient mutants.

    GAs are indispensable for the development of fertile flowers. Fertility of GA-deficient flowers is restored

  4. Effect of abscisic acid on stomatal opening in isolated epidermal strips of abi mutants of Arabidopsis thaliana

    NARCIS (Netherlands)

    Roelfsema, MRG; Prins, HBA

    1995-01-01

    Abscisic acid-insensitive mutants of Arabidopsis thaliana L. var. Landsberg erecta were selected for their decreased sensitivity to ABA during germination. Two of these mutants, abi-1 and abi-2, display a wilty phenotype as adult plants, indicating disturbed water relations. Experiments were

  5. Spatio-temporal changes in endogenous abscisic acid contents during etiolated growth and photomorphogenesis in tomato seedlings

    Czech Academy of Sciences Publication Activity Database

    Humplík, Jan; Turečková, Veronika; Fellner, Martin; Bergougnoux, V.

    2015-01-01

    Roč. 10, č. 8 (2015), č. článku e1039213. ISSN 1559-2316 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : arabidopsis seedlings * blue-light * phytochromes * germination * metabolism * dormancy * barley * seeds * abscisic acid * blue-light * etiolated growth * photomorphogenesis * tomato Subject RIV: EB - Genetics ; Molecular Biology

  6. Cytokinins and Abscisic Acid Act Antagonistically in the Regulation of the Bud Outgrowth Pattern by Light Intensity

    Directory of Open Access Journals (Sweden)

    Adrien Corot

    2017-10-01

    Full Text Available Bud outgrowth is a key process in the elaboration of yield and visual quality in rose crops. Although light intensity is well known to affect bud outgrowth, little is known on the mechanisms involved in this regulation. The objective of this work was to test if the control of bud outgrowth pattern along the stem by photosynthetic photon flux density (PPFD is mediated by sugars, cytokinins and/or abscisic acid in intact rose plants. Rooted cuttings of Rosa hybrida ‘Radrazz’ were grown in growth chambers under high PPFD (530 μmol m-2 s-1 until the floral bud visible stage. Plants were then either placed under low PPFD (90 μmol m-2 s-1 or maintained under high PPFD. Bud outgrowth inhibition by low PPFD was associated with lower cytokinin and sugar contents and a higher abscisic acid content in the stem. Interestingly, cytokinin supply to the stem restored bud outgrowth under low PPFD. On the other hand, abscisic acid supply inhibited outgrowth under high PPFD and antagonized bud outgrowth stimulation by cytokinins under low PPFD. In contrast, application of sugars did not restore bud outgrowth under low PPFD. These results suggest that PPFD regulation of bud outgrowth in rose involves a signaling pathway in which cytokinins and abscisic acid play antagonistic roles. Sugars can act as nutritional and signaling compounds and may be involved too, but do not appear as the main regulator of the response to PPFD.

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

    DEFF Research Database (Denmark)

    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......[A,C,G]CGT as ATAF1 consensus binding sequences. Co-expression analysis across publicly available microarray experiments identified 25 genes co-expressed with ATAF1. The promoter regions of ATAF1 co-expressors were significantly enriched for ATAF1 binding sites, and TTGCGTA was identified in the promoter of the 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....

  8. Developmental priming of stomatal sensitivity to abscisic acid by leaf microclimate.

    Science.gov (United States)

    Pantin, Florent; Renaud, Jeanne; Barbier, François; Vavasseur, Alain; Le Thiec, Didier; Rose, Christophe; Bariac, Thierry; Casson, Stuart; McLachlan, Deirdre H; Hetherington, Alistair M; Muller, Bertrand; Simonneau, Thierry

    2013-09-23

    Plant water loss and CO2 uptake are controlled by valve-like structures on the leaf surface known as stomata. Stomatal aperture is regulated by hormonal and environmental signals. We show here that stomatal sensitivity to the drought hormone abscisic acid (ABA) is acquired during leaf development by exposure to an increasingly dryer atmosphere in the rosette plant Arabidopsis. Young leaves, which develop in the center of the rosette, do not close in response to ABA. As the leaves increase in size, they are naturally exposed to increasingly dry air as a consequence of the spatial arrangement of the leaves, and this triggers the acquisition of ABA sensitivity. Interestingly, stomatal ABA sensitivity in young leaves is rapidly restored upon water stress. These findings shed new light on how plant architecture and stomatal physiology have coevolved to optimize carbon gain against water loss in stressing environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. A new look at stress: abscisic acid patterns and dynamics at high-resolution.

    Science.gov (United States)

    Jones, Alexander M

    2016-04-01

    Abscisic acid (ABA) is a key phytohormone promoting abiotic stress tolerance as well as developmental processes such as seed dormancy. A spatiotemporal map of ABA concentrations would greatly advance our understanding of the cell type and timing of ABA action. Organ and tissue-level ABA measurements, as well as indirect in vivo measurements such as cell-specific transcriptional analysis of ABA metabolic enzymes and ABA-responsive promoters, have all contributed to current views of the localization and timing of ABA accumulations. Recently developed Förster resonance energy transfer (FRET) biosensors for ABA that sense ABA levels directly promise to add unprecedented resolution to in vivo ABA spatiotemporal mapping and expand our knowledge of the mechanisms controlling ABA levels in space and time. © 2015 Carnegie Institution for Science New Phytologist © 2015 New Phytologist Trust.

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

    DEFF Research Database (Denmark)

    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...

  11. ABSCISIC ACID EFFECTS ON WATER AND PHOTOSYNTHETIC CHARACTERISTICS OF TWO ECOTYPES OF Atriplex halimus L.

    Directory of Open Access Journals (Sweden)

    Y. Bidai

    2016-05-01

    Full Text Available The aim of this study is to compare the water and photosynthetic characteristics of two xerophilic ecotypes of Atriplex halimus (L.. Seeds collected from two different sites Djelfa and Oran are germinated in controlled greenhouse. After 6 months, the plantlets were treated 21 days with increasing concentrations of abscisic acid (0M, 10-6 M and 10-3 M. The results show that ecotype of Djelfa reduced water loss through transpiration because of high stomatal resistance. Consequently the content of chlorophyll a and b decrease significantly compared to Oran ecotype which show an increase of the osmotic potential and relative water content. Osmotic adjustment to reduce dehydration and maintain a good photosynthesis seems efficient in Oran ecotype.

  12. Abscisic-acid-dependent basic leucine zipper (bZIP) transcription factors in plant abiotic stress.

    Science.gov (United States)

    Banerjee, Aditya; Roychoudhury, Aryadeep

    2017-01-01

    One of the major causes of significant crop loss throughout the world is the myriad of environmental stresses including drought, salinity, cold, heavy metal toxicity, and ultraviolet-B (UV-B) rays. Plants as sessile organisms have evolved various effective mechanism which enable them to withstand this plethora of stresses. Most of such regulatory mechanisms usually follow the abscisic-acid (ABA)-dependent pathway. In this review, we have primarily focussed on the basic leucine zipper (bZIP) transcription factors (TFs) activated by the ABA-mediated signalosome. Upon perception of ABA by specialized receptors, the signal is transduced via various groups of Ser/Thr kinases, which phosphorylate the bZIP TFs. Following such post-translational modification of TFs, they are activated so that they bind to specific cis-acting sequences called abscisic-acid-responsive elements (ABREs) or GC-rich coupling elements (CE), thereby influencing the expression of their target downstream genes. Several in silico techniques have been adopted so far to predict the structural features, recognize the regulatory modification sites, undergo phylogenetic analyses, and facilitate genome-wide survey of TF under multiple stresses. Current investigations on the epigenetic regulation that controls greater accessibility of the inducible regions of DNA of the target gene to the bZIP TFs exclusively under stress situations, along with the evolved stress memory responses via genomic imprinting mechanism, have been highlighted. The potentiality of overexpression of bZIP TFs, either in a homologous or in a heterologous background, in generating transgenic plants tolerant to various abiotic stressors have also been addressed by various groups. The present review will provide a coherent documentation on the functional characterization and regulation of bZIP TFs under multiple environmental stresses, with the major goal of generating multiple-stress-tolerant plant cultivars in near future.

  13. Three Genes That Affect Sugar Sensing (Abscisic Acid Insensitive 4, Abscisic Acid Insensitive 5, and Constitutive Triple Response 1) Are Differentially Regulated by Glucose in Arabidopsis1

    Science.gov (United States)

    Arroyo, Analilia; Bossi, Flavia; Finkelstein, Ruth R.; León, Patricia

    2003-01-01

    Mutant characterization has demonstrated that ABI4 (Abscisic Acid [ABA] Insensitive 4), ABI5 (ABA Insensitive 5), and CTR1 (Constitutive Triple Response 1) genes play an important role in the sugar signaling response in plants. The present study shows that the transcripts of these three genes are modulated by glucose (Glc) independently of the developmental arrest caused by high Glc concentrations. ABI4 and ABI5 transcripts accumulate in response to sugars, whereas the CTR1 transcript is transiently reduced followed by a rapid recovery. The results of our kinetic studies on gene expression indicate that ABI4, ABI5, and CTR1 are regulated by multiple signals including Glc, osmotic stress, and ABA. However, the differential expression profiles caused by these treatments suggest that distinct signaling pathways are used for each signal. ABI4 and ABI5 response to the Glc analog 2-deoxy-Glc supports this conclusion. Glc regulation of ABI4 and CTR1 transcripts is dependent on the developmental stage. Finally, the Glc-mediated regulation of ABI4 and ABI5 is affected in mutants displaying Glc-insensitive phenotypes such as gins, abas, abi4, abi5, and ctr1 but not in abi1-1, abi2-1, and abi3-1, which do not show a Glc-insensitive phenotype. The capacity of transcription factors, like the ones analyzed in this work, to be regulated by a variety of signals might contribute to the ability of plants to respond in a flexible and integral way to continuous changes in the internal and external environment. PMID:12970489

  14. An abscisic acid-independent oxylipin pathway controls stomatal closure and immune defense in Arabidopsis.

    Science.gov (United States)

    Montillet, Jean-Luc; Leonhardt, Nathalie; 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.

  15. An abscisic acid-independent oxylipin pathway controls stomatal closure and immune defense in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Jean-Luc Montillet

    Full Text Available 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.

  16. Heat-stable proteins and abscisic acid action in barley aleurone cells

    International Nuclear Information System (INIS)

    Jacobsen, J.V.; Shaw, D.C.

    1989-01-01

    [ 35 S]Methionine labeling experiments showed that abscisic acid (ABA) induced the synthesis of at least 25 polypeptides in mature barley (Hordeum vulgare) aleurone cells. The polypeptides were not secreted. Whereas most of the proteins extracted from aleurone cells were coagulated by heating to 100 degree C for 10 minutes, most of the ABA-induced polypeptides remained in solution (heat-stable). ABA had little effect on the spectrum of polypeptides that were synthesized and secreted by aleurone cells, and most of these secreted polypeptides were also heat-stable. Coomassie blue staining of sodium dodecyl sulfate polyacrylamide gels indicated that ABA-induced polypeptides already occurred in high amounts in mature aleurone layers having accumulated during grain development. About 60% of the total protein extracted from mature aleurone was heat stable. Amino acid analyses of total preparations of heat-stable and heat-labile proteins showed that, compared to heat-labile proteins, heat-stable intracellular proteins were characterized by higher glutamic acid/glutamine (Glx) and glycine levels and lower levels of neutral amino acids. Secreted heat-stable proteins were rich in Glx and proline. The possibilities that the accumulation of the heat-stable polypeptides during grain development is controlled by ABA and that the function of these polypeptides is related to their abundance and extraordinary heat stability are considered

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

    Science.gov (United States)

    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

  18. 1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds

    Czech Academy of Sciences Publication Activity Database

    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

  19. Immunolocalization of endogenous indole-3-acetic acid and abscisic acid in the shoot internodes of Fargesia yunnanensis bamboo during development

    Science.gov (United States)

    Shuguang Wang; Yongpeng Ma; Chengbin Wan; Chungyun Hse; Todd F. Shupe; Yujun Wang; Changming. Wang

    2016-01-01

    The Bambusoideae subfamily includes the fastest-growing plants worldwide, as a consequence of fast internode elongation. However, few studies have evaluated the temporal and spatial distribution of endogenous hormones during internode elongation. In this paper, endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) were detected in different developmental...

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

    Science.gov (United States)

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

    2016-02-01

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

  1. Ethylene limits abscisic acid- or soil drying-induced stomatal closure in aged wheat leaves.

    Science.gov (United States)

    Chen, Lin; Dodd, Ian C; Davies, William J; Wilkinson, Sally

    2013-10-01

    The mechanism of age-induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA- or soil drying-induced stomatal closure of older leaves was partly restored by pretreating plants with 1-methylcyclopropene (1-MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C-2, which contains 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water-use efficiency. © 2013 John Wiley & Sons Ltd.

  2. Interplay between Carotenoids, Abscisic Acid and Jasmonate Guides the Compatible Rice-Meloidogyne graminicola Interaction

    Directory of Open Access Journals (Sweden)

    Tina Kyndt

    2017-06-01

    Full Text Available In this study, we have characterized the role of carotenoids and chlorophyll in the compatible interaction between the sedentary root knot nematode (RKN Meloidogyne graminicola and the monocot model plant rice (Oryza sativa. Previous transcriptome data showed a differential expression of carotenoid and chlorophyll biosynthesis genes in nematode-induced giant cells and gall tissue. Metabolite measurement showed that galls indeed accumulate chlorophyll a, b and carotenoids, as well as the hormone abscisic acid (ABA. When ABA was externally applied on rice plants, or when ABA-biosynthesis was inhibited, a significant increase in gall formation and nematode development was found, showing the complex role of ABA in this interaction. ABA application suppressed jasmonic acid (JA levels in the plants, while ABA-biosynthesis inhibition lead to increased JA levels confirming an antagonism between ABA and JA in rice roots. In addition, combined applications of ABA and JA showed that the ABA-effect can overcome JA-induced defense. Based on these observations, we hypothesized that the accumulation of chlorophyll and carotenoid precursors would be beneficial to nematode infection. Indeed, when chemically blocking the carotenoid biosynthesis pathway at different steps, which leads to differential accumulation of carotenoids and chlorophyll in the plants, a positive and clear link between accumulation of carotenoids and chlorophyll and rice susceptibility to RKN was detected.

  3. Functional convergence of oxylipin and abscisic acid pathways controls stomatal closure in response to drought.

    Science.gov (United States)

    Savchenko, Tatyana; Kolla, Venkat A; Wang, Chang-Quan; Nasafi, Zainab; Hicks, Derrick R; Phadungchob, Bpantamars; Chehab, Wassim E; Brandizzi, Federica; Froehlich, John; Dehesh, Katayoon

    2014-03-01

    Membranes are primary sites of perception of environmental stimuli. Polyunsaturated fatty acids are major structural constituents of membranes that also function as modulators of a multitude of signal transduction pathways evoked by environmental stimuli. Different stresses induce production of a distinct blend of oxygenated polyunsaturated fatty acids, "oxylipins." We employed three Arabidopsis (Arabidopsis thaliana) ecotypes to examine the oxylipin signature in response to specific stresses and determined that wounding and drought differentially alter oxylipin profiles, particularly the allene oxide synthase branch of the oxylipin pathway, responsible for production of jasmonic acid (JA) and its precursor 12-oxo-phytodienoic acid (12-OPDA). Specifically, wounding induced both 12-OPDA and JA levels, whereas drought induced only the precursor 12-OPDA. Levels of the classical stress phytohormone abscisic acid (ABA) were also mainly enhanced by drought and little by wounding. To explore the role of 12-OPDA in plant drought responses, we generated a range of transgenic lines and exploited the existing mutant plants that differ in their levels of stress-inducible 12-OPDA but display similar ABA levels. The plants producing higher 12-OPDA levels exhibited enhanced drought tolerance and reduced stomatal aperture. Furthermore, exogenously applied ABA and 12-OPDA, individually or combined, promote stomatal closure of ABA and allene oxide synthase biosynthetic mutants, albeit most effectively when combined. Using tomato (Solanum lycopersicum) and Brassica napus verified the potency of this combination in inducing stomatal closure in plants other than Arabidopsis. These data have identified drought as a stress signal that uncouples the conversion of 12-OPDA to JA and have revealed 12-OPDA as a drought-responsive regulator of stomatal closure functioning most effectively together with ABA.

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

    Science.gov (United States)

    Hansen, Hauke; Grossmann, Klaus

    2000-01-01

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

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

    International Nuclear Information System (INIS)

    Hussain, S.; Iqbal, J.; Ibrahim, M.; Atta, S.; Ahmed, T.; Saleem, M.F.

    2014-01-01

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Effects of abscisic acid and brassinolide on photosynthetic characteristics of Leymus chinensis from Songnen Plain grassland in Northeast China.

    Science.gov (United States)

    Hu, Yong-Jun; Shi, Lian-Xuan; Sun, Wei; Guo, Ji-Xun

    2013-12-01

    It has been well demonstrated that plant growth regulators have important functions in multiple physiological processes. ABA and BR play crucial roles in response of crops to stresses. Photosynthetic capacity of Leymus. chinensis treated by various concentrations of ABA and BR in combination was determined. Further more, the mechanisms of ABA and BR treatments and potential for recovery of saline-alkali grasslands were discussed. Abscisic acid (ABA) and brassinolide (BR) affected leaf gas exchange, growth and biomass of L. chinensis. The application of ABA and BR mixtures, especially that of 0.01 mM ABA and 2 × 10 -4  mM BR, increased the net photosynthetic rate, stomatal conductance, water use efficiency, the maximum net photosynthetic rate, light-saturated rate, leaf respiration rate, the maximum RUBP carboxylation rate, the maximum electron transport rate, the maximum triose-phosphate utilization, carboxylation efficiency and the quantum efficiency of PSII and subsequently enhanced density, height and biomass in L. chinensis. We also observed reduction in the light compensation and saturation points following the application of ABA and BR treatments. We concluded that proper use of plant growth regulators can enhance the plant growth and productivity on the Songnen grassland, which is particularly important for the improvement of saline - alkaline grassland and the yield of grazing lands.

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

    Czech Academy of Sciences Publication Activity Database

    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

  9. Abscinazole-E3M, a practical inhibitor of abscisic acid 8?-hydroxylase for improving drought tolerance

    OpenAIRE

    Takeuchi, Jun; Okamoto, Masanori; Mega, Ryosuke; Kanno, Yuri; Ohnishi, Toshiyuki; Seo, Mitsunori; Todoroki, Yasushi

    2016-01-01

    Abscisic acid (ABA) is an essential phytohormone that regulates plant water use and drought tolerance. However, agricultural applications of ABA have been limited because of its rapid inactivation in plants, which involves hydroxylation of ABA by ABA 8?-hydroxylase (CYP707A). We previously developed a selective inhibitor of CYP707A, (?)-Abz-E2B, by structurally modifying S-uniconazole, which functions as an inhibitor of CYP707A and as a gibberellin biosynthetic enzyme. However, its synthetic ...

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

    Czech Academy of Sciences Publication Activity Database

    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 - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : Assimilate transfer * barley endosperm * gibberellin-to- abscisic acid balances Subject RIV: EF - Botanics Impact factor: 5.526, year: 2014

  11. Xanthophylls and abscisic acid biosynthesis in water-stressed bean leaves

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Walton, D.C.

    1987-12-01

    Experiments were designed to obtain evidence about the possible role of xanthophylls as abscisic acid (ABA) precursors in water-stressed leaves of Phaseolus vularis L. Leaves were exposed to /sup 14/CO/sub 2/ and the specific activities of several major leaf xanthophylls and stress-induced ABA were determined after a chase in /sup 12/CO/sub 2/ for varying periods of time. The ABA specific radioactivities were about 30 to 70% of that of lutein and violaxanthin regardless of the chase period. The specific activity of neoxanthin, however, was only about 15% of that of ABA. The effects of fluridone on xanthophyll and ABA levels and the extent of labeling of both from /sup 14/CO/sub 2/ were determined. Fluridone did not inhibit the accumulation of ABA when leaves were stressed once, although subsequent stresses in the presence of fluridone did lead to a reduced ABA accumulation. The incorporation of /sup 14/C from /sup 14/CO/sub 2/ into ABA and the xanthophylls was inhibited by fluridone and to about the same extent. The incorporation of /sup 18/O into ABA from violaxanthin which had been labeled in situ by means of the violaxanthin cycle was measured. The results indicated that a portion of the ABA accumulated during stress was formed from violaxanthin which had been labeled with /sup 18/O. The results of these experiments are consistent with a preformed xanthophyll(s) as the major ABA precursor in water-stressed bean leaves.

  12. Tetraploid Rangpur lime rootstock increases drought tolerance via enhanced constitutive root abscisic acid production.

    Science.gov (United States)

    Allario, Thierry; Brumos, Javier; Colmenero-Flores, Jose M; Iglesias, Domingo J; Pina, Jose A; Navarro, Luis; Talon, Manuel; Ollitrault, Patrick; Morillon, Raphaël

    2013-04-01

    Whole-genome duplication, or polyploidy, is common in many plant species and often leads to better adaptation to adverse environmental condition. However, little is known about the physiological and molecular determinants underlying adaptation. We examined the drought tolerance in diploid (2x) and autotetraploid (4x) clones of Rangpur lime (Citrus limonia) rootstocks grafted with 2x Valencia Delta sweet orange (Citrus sinensis) scions, named V/2xRL and V/4xRL, respectively. Physiological experiments to study root-shoot communication associated with gene expression studies in roots and leaves were performed. V/4xRL was much more tolerant to water deficit than V/2xRL. Gene expression analysis in leaves and roots showed that more genes related to the response to water stress were differentially expressed in V/2xRL than in V/4xRL. Prior to the stress, when comparing V/4xRL to V/2xRL, V/4xRL leaves had lower stomatal conductance and greater abscisic acid (ABA) content. In roots, ABA content was higher in V/4xRL and was associated to a greater expression of drought responsive genes, including CsNCED1, a pivotal regulatory gene of ABA biosynthesis. We conclude that tetraploidy modifies the expression of genes in Rangpur lime citrus roots to regulate long-distance ABA signalling and adaptation to stress. © 2012 Blackwell Publishing Ltd.

  13. Effect of Abscisic Acid on Accumulation of Five Active Components in Root of Glycyrrhiza uralensis

    Directory of Open Access Journals (Sweden)

    Jing Qiao

    2017-11-01

    Full Text Available Licorice is one of the most generally used herbal medicines in the world; however, wild licorice resources have decreased drastically. Cultivated Glycyrrhiza uralensis Fischer are the main source of licorice at present, but the content of main active components in cultivated G. uralensis are lower than in wild G. uralensis. Therefore, the production of high-quality cultivated G. uralensis is an urgent issue for the research and production fields. In this study, the content of five active components and seven endogenous phytohormones in cultivated G. uralensis (two-year-old were determined by high-performance liquid chromatography (HPLC and enzyme-linked immunosorbent assay (ELISA, respectively. Furthermore, different concentrations (25–200 mg/L of exogenous abscisic acid (ABA were sprayed on the leaves of G. uralensis in the fast growing period. Results showed that ABA, zeatin riboside (ZR, and dihydrozeatin riboside (DHZR had strong correlation with active components. In addition, the content of five active components increased remarkably after ABA treatment. Our results indicate that ABA is significantly related to the accumulation of active components in G. uralensis, and the application of exogenous ABA at the proper concentration is able to promote the accumulation of main components in G. uralensis.

  14. Color of berry and juice of 'Isabel' grape treated with abscisic acid in different ripening stages

    Directory of Open Access Journals (Sweden)

    Lilian Yukari Yamamoto

    2015-12-01

    Full Text Available Abstract : The objective of this work was to evaluate the effect of (S-cis-abscisic acid (S-ABA application at different ripening stages, in increasing phenolic compounds and color of berry and juice of 'Isabel' grape (Vitis labrusca. The evaluated treatments were: control, without S-ABA application; 400 mg L-1S-ABA applied 7 days before veraison (DBV + 400 mg L-1S-ABA at 35 days after first application (DAFA; 400 mg L-1S-ABA applied at veraison (V + 400 mg L-1S-ABA at 35 DAFA; and 400 mg L-1S-ABA applied 7 days after veraison (DAV + 400 mg L-1S-ABA at 35 DAFA. There was no difference among treatments regarding the physical characteristics of berries and clusters, as well as total polyphenols in berry and juice. However, there was an increase in total anthocyanins in berry and juice with S-ABA application. Colorimetric variables indicated the increase in color of berry treated with S-ABA. Juices produced from grapes treated with S-ABA were more appreciated by tasters. The treatments with 400 mg L-1S-ABA applied 7 days before, during, or 7 days after veraison, combined with an additional application 35 days after the first one, increment total anthocyanin concentration and color of berry and juice of 'Isabel' grape, with better juice acceptance, without affecting total polyphenol concentration.

  15. Overexpression of the transcription factor NF-YC9 confers abscisic acid hypersensitivity in Arabidopsis.

    Science.gov (United States)

    Bi, Chao; Ma, Yu; Wang, Xiao-Fang; Zhang, Da-Peng

    2017-11-01

    Nuclear factor Y (NF-Y) family proteins are involved in many developmental processes and responses to environmental cues in plants, but whether and how they regulate phytohormone abscisic acid (ABA) signaling need further studies. In the present study, we showed that over-expression of the NF-YC9 gene confers ABA hypersensitivity in both the early seedling growth and stomatal response, while down-regulation of NF-YC9 does not affect ABA response in these processes. We also showed that over-expression of the NF-YC9 gene confers salt and osmotic hypersensitivity in early seedling growth, which is likely to be directly associated with the ABA hypersensitivity. Further, we observed that NF-YC9 physically interacts with the ABA-responsive bZIP transcription factor ABA-INSENSITIVE5 (ABI5), and facilitates the function of ABI5 to bind and activate the promoter of a target gene EM6. Additionally, NF-YC9 up-regulates expression of the ABI5 gene in response to ABA. These findings show that NF-YC9 may be involved in ABA signaling as a positive regulator and likely functions redundantly together with other NF-YC members, and support the model that the NF-YC9 mediates ABA signaling via targeting to and aiding the ABA-responsive transcription factors such as ABI5.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    Zhang, L.; Li, X.; Li, B.; Han, M.; Liu, F.; Zhang, L.; Zheng, P.

    2014-01-01

    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)

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

    KAUST Repository

    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.

  19. Abscisic acid in needles of Pinus cembra in relation to ozone exposure.

    Science.gov (United States)

    Bianco; Dalstein

    1999-10-01

    Ozone pollution was analyzed in arolla pine (Pinus cembra L.) forests growing over two mountain ranges located in southern France by using specific ozone-sensitive tobacco plants as bio-indicators and a physico-chemical analyzer. Concentrations of abscisic acid (ABA) were determined in needles of healthy and declining trees in a massif with a declining forest and in a massif with a healthier forest. In addition, ABA was quantified in needles of trees exposed to either charcoal-filtered air or unfiltered air supplemented with ozone in open-top chambers located at the Col du Donon. The concentration of ABA in needles of injured trees increased when the trees were exposed to ozone either under field conditions or in open-top chambers; however, the difference in ABA concentration between control and ozone-exposed needles was less in the open-top chambers, where ozone was the sole variable, than in the field. The results are discussed in the context of the effects of ozone on plant water relations and hormone-mediated cell defense.

  20. Abscisic acid mediates the formation of a suberized stem scar tissue in tomato fruits.

    Science.gov (United States)

    Leide, Jana; Hildebrandt, Ulrich; Hartung, Wolfram; Riederer, Markus; Vogg, Gerd

    2012-04-01

    During harvest, fleshy berry tomato fruits (Solanum lycopersicum) were wounded at their stem scar. Within 3 d, this wound was rapidly sealed by a process covering the wound site with a membranous layer which effectively protects the tomato fruit from excessive water loss, nutrient elution and the entry of pathogens. Chemical analysis of the de novo synthesized stem scar tissue revealed the presence of aromatic and aliphatic components characteristic of the biopolyester suberin. Gene expression patterns associated with suberization were identified at the stem scar region. Changes in the relative abundance of different transcripts suggested a potential involvement of the plant hormone abscisic acid (ABA) in the wound-healing processes. The amount of ABA present in the stem scar tissue showed a significantly increased level during wound healing, whereas ABA-deficient mutants notabilis, flacca and sitiens were largely devoid of this rise in ABA levels. The mutant fruits showed a retarded and less efficient suberization response at the stem scar wound, whereas the rate and strength of this response were positively correlated with ABA content. These results clearly indicate in vivo the involvement of ABA in the suberization-based wound-healing processes at the stem scar tissue of tomato fruits. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  1. Priming effect of abscisic acid on alkaline stress tolerance in rice (Oryza sativa L.) seedlings.

    Science.gov (United States)

    Wei, Li-Xing; Lv, Bing-Sheng; Wang, Ming-Ming; Ma, Hong-Yuan; Yang, Hao-Yu; Liu, Xiao-Long; Jiang, Chang-Jie; Liang, Zheng-Wei

    2015-05-01

    Saline-alkaline stress is characterized by high salinity and high alkalinity (high pH); alkaline stress has been shown to be the primary factor inhibiting rice seedling growth. In this study, we investigated the potential priming effect of abscisic acid (ABA) on tolerance of rice seedlings to alkaline stress simulated by Na2CO3. Seedlings were pretreated with ABA at concentrations of 0 (control), 10, and 50 μM by root-drench for 24 h and then transferred to a Na2CO3 solution that did not contain ABA. Compared to control treatment, pretreatment with ABA substantially improved the survival rate of rice seedlings and increased biomass accumulation after 7 days under the alkaline condition. ABA application at 10 μM also alleviated the inhibitory effects of alkaline stress on the total root length and root surface area. Physiologically, ABA increased relative water content (RWC) and decreased cell membrane injury degree (MI) and Na(+)/K(+) ratios. In contrast, fluridone (an ABA biosynthesis inhibitor) decreased the RWC and increased MI in shoots under the alkaline conditions. These data suggest that ABA has a potent priming effect on the adaptive response to alkaline stress in rice and may be useful for improving rice growth in saline-alkaline paddy fields. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  2. Desiccation tolerance in Physcomitrella patens: Rate of dehydration and the involvement of endogenous abscisic acid (ABA).

    Science.gov (United States)

    Xiao, Lihong; Yobi, Abou; Koster, Karen L; He, Yikun; Oliver, Melvin J

    2018-01-01

    The moss Physcomitrella patens, a model system for basal land plants, tolerates several abiotic stresses, including dehydration. We previously reported that Physcomitrella patens survives equilibrium dehydration to -13 MPa in a closed system at 91% RH. Tolerance of desiccation to water potentials below -100 MPa was only achieved by pretreatment with exogenous abscisic acid (ABA). We report here that gametophores, but not protonemata, can survive desiccation below -100 MPa after a gradual drying regime in an open system, without exogenous ABA. In contrast, faster equilibrium drying at 90% RH for 3-5 days did not induce desiccation tolerance in either tissue. Endogenous ABA accumulated in protonemata and gametophores under both drying regimes, so did not correlate directly with desiccation tolerance. Gametophores of a Ppabi3a/b/c triple knock out transgenic line also survived the gradual dehydration regime, despite impaired ABA signaling. Our results suggest that the initial drying rate, and not the amount of endogenous ABA, may be critical in the acquisition of desiccation tolerance. Results from this work will provide insight into ongoing studies to uncover the role of ABA in the dehydration response and the underlying mechanisms of desiccation tolerance in this bryophyte. © 2017 John Wiley & Sons Ltd.

  3. Autocrine abscisic acid mediates the UV-B-induced inflammatory response in human granulocytes and keratinocytes.

    Science.gov (United States)

    Bruzzone, Santina; Basile, Giovanna; Mannino, Elena; Sturla, Laura; Magnone, Mirko; Grozio, Alessia; Salis, Annalisa; Fresia, Chiara; Vigliarolo, Tiziana; Guida, Lucrezia; De Flora, Antonio; Tossi, Vanesa; Cassia, Raul; Lamattina, Lorenzo; Zocchi, Elena

    2012-06-01

    UV-B is an abiotic environmental stress in both plants and animals. Abscisic acid (ABA) is a phytohormone regulating fundamental physiological functions in plants, including response to abiotic stress. We previously demonstrated that ABA is an endogenous stress hormone also in animal cells. Here, we investigated whether autocrine ABA regulates the response to UV-B of human granulocytes and keratinocytes, the cells involved in UV-triggered skin inflammation. The intracellular ABA concentration increased in UV-B-exposed granulocytes and keratinocytes and ABA was released into the supernatant. The UV-B-induced production of NO and of reactive oxygen species (ROS), phagocytosis, and cell migration were strongly inhibited in granulocytes irradiated in the presence of a monoclonal antibody against ABA. Moreover, presence of the same antibody strongly inhibited release of NO, prostaglandin E2 (PGE(2)), and tumor necrosis factor-α (TNF-α) by UV-B irradiated keratinocytes. Lanthionine synthetase C-like protein 2 (LANCL2) is required for the activation of the ABA signaling pathway in human granulocytes. Silencing of LANCL2 in human keratinocytes by siRNA was accompanied by abrogation of the UV-B-triggered release of PGE(2), TNF-α, and NO and ROS production. These results indicate that UV-B irradiation induces ABA release from human granulocytes and keratinocytes and that autocrine ABA stimulates cell functions involved in skin inflammation. Copyright © 2011 Wiley Periodicals, Inc.

  4. Autocrine abscisic acid plays a key role in quartz-induced macrophage activation.

    Science.gov (United States)

    Magnone, Mirko; Sturla, Laura; Jacchetti, Emanuela; Scarfì, Sonia; Bruzzone, Santina; Usai, Cesare; Guida, Lucrezia; Salis, Annalisa; Damonte, Gianluca; De Flora, Antonio; Zocchi, Elena

    2012-03-01

    Inhalation of quartz induces silicosis, a lung disease where alveolar macrophages release inflammatory mediators, including prostaglandin-E(2) (PGE(2)) and tumor necrosis factor α (TNF-α). Here we report the pivotal role of abscisic acid (ABA), a recently discovered human inflammatory hormone, in silica-induced activation of murine RAW264.7 macrophages and of rat alveolar macrophages (AMs). Stimulation of both RAW264.7 cells and AMs with quartz induced a significant increase of ABA release (5- and 10-fold, respectively), compared to untreated cells. In RAW264.7 cells, autocrine ABA released after quartz stimulation sequentially activates the plasma membrane receptor LANCL2 and NADPH oxidase, generating a Ca(2+) influx resulting in NFκ B nuclear translocation and PGE(2) and TNF-α release (3-, 2-, and 3.5-fold increase, respectively, compared to control, unstimulated cells). Quartz-stimulated RAW264.7 cells silenced for LANCL2 or preincubated with a monoclonal antibody against ABA show an almost complete inhibition of NFκ B nuclear translocation and PGE(2) and TNF-α release compared to controls electroporated with a scramble oligonucleotide or preincubated with an unrelated antibody. AMs showed similar early and late ABA-induced responses as RAW264.7 cells. These findings identify ABA and LANCL2 as key mediators in quartz-induced inflammation, providing possible new targets for antisilicotic therapy.

  5. The interaction of strigolactones with abscisic acid during the drought response in rice

    KAUST Repository

    Haider, Imran

    2018-03-09

    Both strigolactones (SLs) and abscisic acid (ABA) biosynthetically originate from carotenoids. Considering their common origin, the interaction of these two hormones at the biosynthetic and/or regulatory level may be anticipated. Here, we show in rice that drought simultaneously induces SL production in the root, and ABA production and the expression of SL biosynthetic genes in the shoot. Under control conditions, the ABA concentration was higher in shoots of the SL biosynthetic rice mutants dwarf10 (d10) and d17 than in wild-type plants, while a similar trend was observed for SL-perception mutant d3. These differences were enhanced under drought. However, drought did not result in an increase in leaf ABA content in rice mutant line d27, carrying a mutation in the gene encoding the first committed enzyme in SL biosynthesis, to the same extent as in the other SL mutants and the wild-type. Accordingly, d10, d17 and d3 lines were more drought tolerant than wild-type plants, whereas d27 displayed decreased tolerance. Finally, over-expression of OsD27 in rice resulted in increased levels of ABA when compared with wild-type plants. We conclude that the SL and ABA pathways are connected with each other through D27, which is playing a crucial role in determining ABA and SL content in rice.

  6. What are the evolutionary origins of stomatal responses to abscisic acid in land plants?

    Science.gov (United States)

    Sussmilch, Frances C; Brodribb, Timothy J; McAdam, Scott A M

    2017-04-01

    The evolution of active stomatal closure in response to leaf water deficit, mediated by the hormone abscisic acid (ABA), has been the subject of recent debate. Two different models for the timing of the evolution of this response recur in the literature. A single-step model for stomatal control suggests that stomata evolved active, ABA-mediated control of stomatal aperture, when these structures first appeared, prior to the divergence of bryophyte and vascular plant lineages. In contrast, a gradualistic model for stomatal control proposes that the most basal vascular plant stomata responded passively to changes in leaf water status. This model suggests that active ABA-driven mechanisms for stomatal responses to water status instead evolved after the divergence of seed plants, culminating in the complex, ABA-mediated responses observed in modern angiosperms. Here we review the findings that form the basis for these two models, including recent work that provides critical molecular insights into resolving this intriguing debate, and find strong evidence to support a gradualistic model for stomatal evolution. © 2017 Institute of Botany, Chinese Academy of Sciences.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    KAUST Repository

    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.

  9. The pivotal role of abscisic acid signaling during transition from seed maturation to germination.

    Science.gov (United States)

    Yan, An; Chen, Zhong

    2017-05-01

    Seed maturation and germination are two continuous developmental processes that link two distinct generations in spermatophytes; the precise genetic control of these two processes is, therefore, crucially important for the survival of the next generation. Pieces of experimental evidence accumulated so far indicate that a concerted action of endogenous signals and environmental cues is required to govern these processes. Plant hormone abscisic acid (ABA) has been suggested to play a predominant role in directing seed maturation and maintaining seed dormancy under unfavorable environmental conditions until antagonized by gibberellins (GA) and certain environmental cues to allow the commencement of seed germination when environmental conditions are favorable; therefore, the balance of ABA and GA is a major determinant of the timing of seed germination. Due to the advent of new technologies and system biology approaches, molecular studies are beginning to draw a picture of the sophisticated genetic network that drives seed maturation during the past decade, though the picture is still incomplete and many details are missing. In this review, we summarize recent advances in ABA signaling pathway in the regulation of seed maturation as well as the transition from seed maturation to germination, and highlight the importance of system biology approaches in the study of seed maturation.

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

    Science.gov (United States)

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

    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. Interestingly, KAR only retarded soybean seed germination under shaded conditions, rather than under dark and white light conditions, which differs from in Arabidopsis. Phytohormone quantification showed that KAR enhanced ABA biogenesis while impairing GA biosynthesis during the seed imbibition process, and subsequently, the ratio of active GA4 to ABA was significantly reduced. Further qRT-PCR analysis showed that the transcription pattern of genes involved in ABA and GA metabolic pathways are consistent with the hormonal measurements. Finally, fluridone, an ABA biogenesis inhibitor, remarkably rescued the delayed-germination phenotype of KAR-treatment; and paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Taken together, these evidences suggest that KAR inhibit soybean seed germination by mediating the ratio between GA and ABA biogenesis. PMID:26902640

  11. Abscisic Acid Regulates Auxin Homeostasis in Rice Root Tips to Promote Root Hair Elongation

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    Tao Wang

    2017-06-01

    Full Text Available Abscisic acid (ABA plays an essential role in root hair elongation in plants, but the regulatory mechanism remains to be elucidated. In this study, we found that exogenous ABA can promote rice root hair elongation. Transgenic rice overexpressing SAPK10 (Stress/ABA-activated protein kinase 10 had longer root hairs; rice plants overexpressing OsABIL2 (OsABI-Like 2 had attenuated ABA signaling and shorter root hairs, suggesting that the effect of ABA on root hair elongation depends on the conserved PYR/PP2C/SnRK2 ABA signaling module. Treatment of the DR5-GUS and OsPIN-GUS lines with ABA and an auxin efflux inhibitor showed that ABA-induced root hair elongation depends on polar auxin transport. To examine the transcriptional response to ABA, we divided rice root tips into three regions: short root hair, long root hair and root tip zones; and conducted RNA-seq analysis with or without ABA treatment. Examination of genes involved in auxin transport, biosynthesis and metabolism indicated that ABA promotes auxin biosynthesis and polar auxin transport in the root tip, which may lead to auxin accumulation in the long root hair zone. Our findings shed light on how ABA regulates root hair elongation through crosstalk with auxin biosynthesis and transport to orchestrate plant development.

  12. Protein degradation mechanisms modulate abscisic acid signaling and responses during abiotic stress.

    Science.gov (United States)

    Jurkiewicz, Pawel; Batoko, Henri

    2018-02-01

    Abiotic stresses such as salinity, drought, high temperature or freezing can be perceived, in part, as a transient or permanent hyperosmotic stress by the plant cell. As sessile organisms, the detrimental effects of these environmental insults limit plants productivity but also their geographical distribution. Sensing and signaling events that detect the hyperosmotic (or simply osmotic) stress involve the cellular increase of active abscisic acid (ABA). The stress phytohormone ABA regulates fundamental growth and developmental processes in the plant by marshalling metabolic and gene-expression reprogramming. Among the ABA-responsive genes, some are strictly ABA-dependent in that their expression is almost undetectable in absence of elevated levels of cellular ABA, thus their physiological role may be required only transiently. In addition, ABA-dependent modulation of some of the signaling effectors can be irreversible. In this review, without any pretention to being exhaustive, we use specific examples to illustrate how mechanistically conserved eukaryotic cell proteolytic pathways affect ABA-dependent signaling. We describe how defined proteolysis mechanisms in the plant cell, including Regulated Intramembrane Proteolysis (RIP), the Ubiquitin 26S Proteasomal System (UPS), the endocytic and autophagy pathways, contribute to regulate the spatiotemporal level and activity of PP2Cs (protein phosphatases 2C), and how an intriguing ABA-induced protein, the plant Translocator protein (TSPO), is targeted for degradation. Degradation of regulatory or effector molecules modulates or desensitizes ABA-dependent signaling and reestablishes cellular homeostasis. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Abscisic acid stimulates a calcium-dependent protein kinase in grape berry.

    Science.gov (United States)

    Yu, Xiang-Chun; Li, Mei-Jun; Gao, Gui-Feng; Feng, Hai-Zhong; Geng, Xue-Qing; Peng, Chang-Cao; Zhu, Sai-Yong; Wang, Xiao-Jing; Shen, Yuan-Yue; Zhang, Da-Peng

    2006-02-01

    It has been demonstrated that calcium plays a central role in mediating abscisic acid (ABA) signaling, but many of the Ca2+-binding sensory proteins as the components of the ABA-signaling pathway remain to be elucidated. Here we identified, characterized, and purified a 58-kD ABA-stimulated calcium-dependent protein kinase from the mesocarp of grape berries (Vitis vinifera x Vitis labrusca), designated ACPK1 (for ABA-stimulated calcium-dependent protein kinase1). ABA stimulates ACPK1 in a dose-dependent manner, and the ACPK1 expression and enzyme activities alter accordantly with the endogenous ABA concentrations during fruit development. The ABA-induced ACPK1 stimulation appears to be transient with a rapid effect in 15 min but also with a slow and steady state of induction after 60 min. ABA acts on ACPK1 indirectly and dependently on in vivo state of the tissues. Two inactive ABA isomers, (-)-2-cis, 4-trans-ABA and 2-trans, 4-trans-(+/-)-ABA, are ineffective for inducing ACPK1 stimulation, revealing that the ABA-induced effect is stereo specific to physiological active (+)-2-cis, 4-trans-ABA. The other phytohormones such as auxin indoleacetic acid, gibberellic acid, synthetic cytokinin N-benzyl-6-aminopurine, and brassinolide are also ineffective in this ACPK1 stimulation. Based on sequencing of the two-dimensional electrophoresis-purified ACPK1, we cloned the ACPK1 gene. The ACPK1 is expressed specifically in grape berry covering a fleshy portion and seeds, and in a developmental stage-dependent manner. We further showed that ACPK1 is localized in both plasma membranes and chloroplasts/plastids and positively regulates plasma membrane H+-ATPase in vitro, suggesting that ACPK1 may be involved in the ABA-signaling pathway.

  14. Abscisic Acid Determines Basal Susceptibility of Tomato to Botrytis cinerea and Suppresses Salicylic Acid-Dependent Signaling Mechanisms1

    Science.gov (United States)

    Audenaert, Kris; De Meyer, Geert B.; Höfte, Monica M.

    2002-01-01

    Abscisic acid (ABA) is one of the plant hormones involved in the interaction between plants and pathogens. In this work, we show that tomato (Lycopersicon esculentum Mill. cv Moneymaker) mutants with reduced ABA levels (sitiens plants) are much more resistant to the necrotrophic fungus Botrytis cinerea than wild-type (WT) plants. Exogenous application of ABA restored susceptibility to B. cinerea in sitiens plants and increased susceptibility in WT plants. These results indicate that ABA plays a major role in the susceptibility of tomato to B. cinerea. ABA appeared to interact with a functional plant defense response against B. cinerea. Experiments with transgenic NahG tomato plants and benzo(1,2,3)thiadiazole-7-carbothioic acid demonstrated the importance of salicylic acid in the tomato-B. cinerea interaction. In addition, upon infection with B. cinerea, sitiens plants showed a clear increase in phenylalanine ammonia lyase activity, which was not observed in infected WT plants, indicating that the ABA levels in healthy WT tomato plants partly repress phenylalanine ammonia lyase activity. In addition, sitiens plants became more sensitive to benzo(1,2,3)thiadiazole-7-carbothioic acid root treatment. The threshold values for PR1a gene expression declined with a factor 10 to 100 in sitiens compared with WT plants. Thus, ABA appears to negatively modulate the salicylic acid-dependent defense pathway in tomato, which may be one of the mechanisms by which ABA levels determine susceptibility to B. cinerea. PMID:11842153

  15. A Unique Short-Chain Dehydrogenase/Reductase in Arabidopsis Glucose Signaling and Abscisic Acid Biosynthesis and Functions

    Science.gov (United States)

    Cheng, Wan-Hsing; Endo, Akira; Zhou, Li; Penney, Jessica; Chen, Huei-Chi; Arroyo, Analilia; Leon, Patricia; Nambara, Eiji; Asami, Tadao; Seo, Mitsunori; Koshiba, Tomokazu; Sheen, Jen

    2002-01-01

    Glc has hormone-like functions and controls many vital processes through mostly unknown mechanisms in plants. We report here on the molecular cloning of GLUCOSE INSENSITIVE1 (GIN1) and ABSCISIC ACID DEFICIENT2 (ABA2) which encodes a unique Arabidopsis short-chain dehydrogenase/reductase (SDR1) that functions as a molecular link between nutrient signaling and plant hormone biosynthesis. SDR1 is related to SDR superfamily members involved in retinoid and steroid hormone biosynthesis in mammals and sex determination in maize. Glc antagonizes ethylene signaling by activating ABA2/GIN1 and other abscisic acid (ABA) biosynthesis and signaling genes, which requires Glc and ABA synergistically. Analyses of aba2/gin1 null mutants define dual functions of endogenous ABA in inhibiting the postgermination developmental switch modulated by distinct Glc and osmotic signals and in promoting organ and body size and fertility in the absence of severe stress. SDR1 is sufficient for the multistep conversion of plastid- and carotenoid-derived xanthoxin to abscisic aldehyde in the cytosol. The surprisingly restricted spatial and temporal expression of SDR1 suggests the dynamic mobilization of ABA precursors and/or ABA. PMID:12417697

  16. Visualisation of abscisic acid and 12-oxo-phytodienoic acid in immature Phaseolus vulgaris L. seeds using desorption electrospray ionisation-imaging mass spectrometry

    OpenAIRE

    Enomoto, Hirofumi; Sensu, Takuya; Sato, Kei; Sato, Futoshi; Paxton, Thanai; Yumoto, Emi; Miyamoto, Koji; Asahina, Masashi; Yokota, Takao; Yamane, Hisakazu

    2017-01-01

    The plant hormone abscisic acid (ABA) and the jasmonic acid related-compound 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development, dormancy, and germination. However, a lack of suitable techniques for visualising plant hormones has restricted the investigation of their biological mechanisms. In the present study, desorption electrospray ionisation-imaging mass spectrometry (DESI-IMS), a powerful tool for visualising metabolites in biological tissues, was used to visualise AB...

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

    Science.gov (United States)

    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.

  18. Plastid located WHIRLY1 enhances responsiveness of Arabidopsis seedlings towards abscisic acid

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    Rena eIsemer

    2012-12-01

    Full Text Available WHIRLY1 is a protein that can be translocated from the plastids to the nucleus, making it an ideal candidate for communicating information between these two compartments. Mutants of Arabidopsis thaliana lacking WHIRLY1 (why1 were shown to have a reduced sensitivity towards salicylic acid (SA and abscisic acid (ABA during germination. Germination assays in the presence of abamine, an inhibitor of ABA biosynthesis, revealed that the effect of SA on germination was in fact caused by a concomitant stimulation of ABA biosynthesis. In order to distinguish whether the plastid or the nuclear isoform of WHIRLY1 is adjusting the responsiveness towards ABA, sequences encoding either the complete WHIRLY1 protein or a truncated form lacking the plastid targeting peptide were overexpressed in the why1 mutant background. In plants overex¬pressing the full-length sequence, WHIRLY1 accumulated in both plastids and the nucleus, whereas in plants overexpressing the truncated sequence, WHIRLY1 accumulated exclusively in the nucleus. Seedlings containing recombinant WHIRLY1 in both compartments were hypersen¬sitive towards ABA. In contrast, seedlings possessing only the nuclear form of WHIRLY1 were as insensitive towards ABA as the why1 mutants. ABA was furthermore shown to lower the rate of germination of wildtype seeds even in the presence of abamine which is known to inhibit the formation of xanthoxin, the plastid located precursor of ABA. From this we conclude that plastid located WHIRLY1 enhances the responsiveness of seeds towards ABA even when ABA is supplied exogenously.

  19. Sucrose Loading in Isolated Veins of Pisum sativum: Regulation by Abscisic Acid, Gibberellic Acid, and Cell Turgor 1

    Science.gov (United States)

    Estruch, Juan José; Peretó, Juli G.; Vercher, Yolanda; Beltrán, José Pío

    1989-01-01

    Enzymatically isolated vein networks from mature pea (Pisum sativum L. cv Alaska) leaves were employed to investigate the properties of sucrose loading and the effect of phytohormones and cell turgor on this process. The sucrose uptake showed two components: a saturable and a first-order kinetics system. The high affinity system (Km, 3.3 millimolar) was located at the plasmalemma (p-chloromercuriphenylsulfonic acid and orthovanadate sensitivity). Further characterization of this system, including pH dependence and effects of energy metabolism inhibitors, supported the H+-sugar symport concept for sucrose loading. Within a physiological range (0.1-100 micromolar) and after 90 min, abscisic acid (ABA) inhibited and gibberellic acid (GA3) promoted 1 millimolar sucrose uptake. These responses were partially (ABA) or totally (GA3) turgor-dependent. In experiments of combined hormonal treatments, ABA counteracted the GA3 positive effects on sucrose uptake. The abolishment of these responses by p-chloromercuriphenylsulfonic acid and experiments on proton flux suggest that both factors (cell turgor and hormones) are modulating the H+ ATPase plasmalemma activity. The results are discussed in terms of their physiological relevance. Images Figure 1 PMID:16667007

  20. Cuticle Biosynthesis in Tomato Leaves Is Developmentally Regulated by Abscisic Acid.

    Science.gov (United States)

    Martin, Laetitia B B; Romero, Paco; Fich, Eric A; Domozych, David S; Rose, Jocelyn K C

    2017-07-01

    The expansion of aerial organs in plants is coupled with the synthesis and deposition of a hydrophobic cuticle, composed of cutin and waxes, which is critically important in limiting water loss. While the abiotic stress-related hormone abscisic acid (ABA) is known to up-regulate wax accumulation in response to drought, the hormonal regulation of cuticle biosynthesis during organ ontogeny is poorly understood. To address the hypothesis that ABA also mediates cuticle formation during organ development, we assessed the effect of ABA deficiency on cuticle formation in three ABA biosynthesis-impaired tomato mutants. The mutant leaf cuticles were thinner, had structural abnormalities, and had a substantial reduction in levels of cutin. ABA deficiency also consistently resulted in differences in the composition of leaf cutin and cuticular waxes. Exogenous application of ABA partially rescued these phenotypes, confirming that they were a consequence of reduced ABA levels. The ABA mutants also showed reduced expression of genes involved in cutin or wax formation. This difference was again countered by exogenous ABA, further indicating regulation of cuticle biosynthesis by ABA. The fruit cuticles were affected differently by the ABA-associated mutations, but in general were thicker. However, no structural abnormalities were observed, and the cutin and wax compositions were less affected than in leaf cuticles, suggesting that ABA action influences cuticle formation in an organ-dependent manner. These results suggest dual roles for ABA in regulating leaf cuticle formation: one that is fundamentally associated with leaf expansion, independent of abiotic stress, and another that is drought induced. © 2017 American Society of Plant Biologists. All Rights Reserved.

  1. The regulatory network of ThbZIP1 in response to abscisic acid treatment

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    Xiaoyu eJi

    2015-02-01

    Full Text Available Previously, a bZIP transcription factor from Tamarix hispida, ThbZIP1, was characterized: plants overexpressing ThbZIP1 displayed improved salt stress tolerance but were sensitive to abscisic acid (ABA. In the current study, we further characterized the regulatory network of ThbZIP1 and the mechanism of ABA sensitivity mediated by ThbZIP1. An ABF transcription factor from T. hispida, ThABF1, directly regulates the expression of ThbZIP1. Microarray analysis identified 1,662 and 1,609 genes that were respectively significantly upregulated or downregulated by ThbZIP1 when exposed to ABA. GO analysis showed that the processes including response to stimulus, catalytic activity, binding function, and metabolic process were highly altered in ThbZIP1 expressing plants exposed to ABA. The gene expression in ThbZIP1 transformed plants were compared between exposed to ABA and salt on the genome scale. Genes differentially regulated by both salt and ABA treatment only accounted for 9.75% of total differentially regulated genes. GO analysis showed that structural molecule activity, organelle part, membrane-enclosed lumen, reproduction and reproductive process are enhanced by ABA but inhibited by salt stress. Conversely, immune system and multi-organism process were improved by salt but inhibited by ABA. Transcription regulator activity, enzyme regulator activity and developmental process were significantly altered by ABA but were not affected by salt stress. Our study provides insights into how ThbZIP1 mediates ABA and salt stress response at the molecular level.

  2. Assessing the Effect of Organoclays and Biochar on the Fate of Abscisic Acid in Soil.

    Science.gov (United States)

    Gámiz, Beatriz; Cox, Lucía; Hermosín, M Carmen; Spokas, Kurt; Celis, Rafael

    2017-01-11

    The potential use of allelopathic and signaling compounds as environmentally friendly agrochemicals is a subject of increasing interest, but the fate of these compounds once they reach the soil environment is poorly understood. This work studied how the sorption, persistence, and leaching of the two enantiomers of the phytohormone abscisic acid (ABA) in agricultural soil was affected by the amendments of two organoclays (SA-HDTMA and Cloi10) and a biochar derived from apple wood (BC). In conventional 24-h batch sorption experiments, higher affinity toward ABA enantiomers was displayed by SA-HDTMA followed by Cloi10 and then BC. Desorption could be ascertained only in BC, where ABA enantiomers presented difficulties to be desorbed. Dissipation of ABA in the soil was enantioselective with S-ABA being degraded more quickly than R-ABA, and followed the order unamended > Cloi10-amended > BC-amended > SA-HDTMA-amended soil for both enantiomers. Sorption determined during the incubation experiment indicated some loss of sorption capacity with time in organoclay-amended soil and increasing sorption in BC-amended soil, suggesting surface sorption mechanisms for organoclays and slow (potentially pore filling) kinetics in BC-amended soil. The leaching of ABA enantiomers was delayed after amendment of soil to an extent that depended on the amendment sorption capacity, and it was almost completely suppressed by addition of BC due to its irreversible sorption. Organoclays and BC affected differently the final behavior and enantioselectivity of ABA in soil as a consequence of dissimilar sorption capacities and alterations in sorption with time, which will affect the plant and microbial availability of endogenous and exogenous ABA in the rhizosphere.

  3. Patterns of auxin and abscisic acid movement in the tips of gravistimulated primary roots of maize

    Science.gov (United States)

    Young, L. M.; Evans, M. L.

    1996-01-01

    Because both abscisic acid (ABA) and auxin (IAA) have been suggested as possible chemical mediators of differential growth during root gravitropism, we compared with redistribution of label from applied 3H-IAA and 3H-ABA during maize root gravitropism and examined the relative basipetal movement of 3H-IAA and 3H-ABA applied to the caps of vertical roots. Lateral movement of 3H-ABA across the tips of vertical roots was non-polar and about 2-fold greater than lateral movement of 3H-IAA (also non-polar). The greater movement of ABA was not due to enhanced uptake since the uptake of 3H-IAA was greater than that of 3H-ABA. Basipetal movement of label from 3H-IAA or 3H-ABA applied to the root cap was determined by measuring radioactivity in successive 1 mm sections behind the tip 90 minutes after application. ABA remained largely in the first mm (point of application) whereas IAA was concentrated in the region 2-4 mm from the tip with substantial levels found 7-8 mm from the tip. Pretreatment with inhibitors of polar auxin transport decreased both gravicurvature and the basipetal movement of IAA. When roots were placed horizontally, the movement of 3H-IAA from top to bottom across the cap was enhanced relative to movement from bottom to top whereas the pattern of movement of label from 3H-ABA was unaffected. These results are consistent with the hypothesis that IAA plays a role in root gravitropism but contrary to the idea that gravi-induced asymmetric distribution of ABA contributes to the response.

  4. Stomatal response of an anisohydric grapevine cultivar to evaporative demand, available soil moisture and abscisic acid.

    Science.gov (United States)

    Rogiers, Suzy Y; Greer, Dennis H; Hatfield, Jo M; Hutton, Ron J; Clarke, Simon J; Hutchinson, Paul A; Somers, Anthony

    2012-03-01

    Stomatal responsiveness to evaporative demand (air vapour pressure deficit (VPD)) ranges widely between species and cultivars, and mechanisms for stomatal control in response to VPD remain obscure. The interaction of irrigation and soil moisture with VPD on stomatal conductance is particularly difficult to predict, but nevertheless is critical to instantaneous transpiration and vulnerability to desiccation. Stomatal sensitivity to VPD and soil moisture was investigated in Semillon, an anisohydric Vitis vinifera L. variety whose leaf water potential (Ψ(l)) is frequently lower than that of other grapevine varieties grown under similar conditions in the warm grape-growing regions of Australia. A survey of Semillon vines across seven vineyards revealed that, regardless of irrigation treatment, midday Ψ(l) was dependent on not only soil moisture but VPD at the time of measurement. Predawn Ψ(l) was more closely correlated to not only soil moisture in dry vineyards but to night-time VPD in drip-irrigated vineyards, with incomplete rehydration during high night-time VPD. Daytime stomatal conductance was low only under severe plant water deficits, induced by extremes in dry soil. Stomatal response to VPD was inconsistent across irrigation regime; however, in an unirrigated vineyard, stomatal sensitivity to VPD-the magnitude of stomatal response to VPD-was heightened under dry soils. It was also found that stomatal sensitivity was proportional to the magnitude of stomatal conductance at a reference VPD of 1kPa. Exogenous abscisic acid (ABA) applied to roots of Semillon vines growing in a hydroponic system induced stomatal closure and, in field vines, petiole xylem sap ABA concentrations rose throughout the morning and were higher in vines with low Ψ(l). These data indicate that despite high stomatal conductance of this anisohydric variety when grown in medium to high soil moisture, increased concentrations of ABA as a result of very limited soil moisture may augment

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

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    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.

  6. Homologous Recombination Defective Arabidopsis Mutants Exhibit Enhanced Sensitivity to Abscisic Acid.

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    Sujit Roy

    Full Text Available Abscisic acid (ABA acts as an important plant hormone in regulating various aspects of plant growth and developmental processes particularly under abiotic stress conditions. An increased ABA level in plant cells inhibits DNA replication and cell division, causing plant growth retardation. In this study, we have investigated the effects of ABA on the growth responses of some major loss-of-function mutants of DNA double-stand break (DSB repair genes in Arabidopsis during seed germination and early stages of seedling growth for understanding the role of ABA in the induction of genome instability in plants. A comparative analysis of ABA sensitivity of wild-type Arabidopsis and the knockout mutant lines related to DSB sensors, including atatm, atatr, the non-homologous end joining (NHEJ pathway genes, and mutants related to homologous recombination (HR pathway genes showed relatively enhanced sensitivity of atatr and HR-related mutants to ABA treatment. The expression levels of HR-related genes were increased in wild-type Arabidopsis (Col-0 during seed germination and early stages of seedling growth. Immunoblotting experiments detected phosphorylation of histone H2AX in wild-type (Col-0 and DSB repair gene mutants after ABA treatment, indicating the activation of DNA damage response due to ABA treatment. Analyses of DSB repair kinetics using comet assay under neutral condition have revealed comparatively slower DSB repair activity in HR mutants. Overall, our results have provided comprehensive information on the possible effect of ABA on DNA repair machinery in plants and also indicated potential functional involvement of HR pathway in repairing ABA induced DNA damage in Arabidopsis.

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

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    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

  8. Abscisic acid pathway involved in the regulation of watermelon fruit ripening and quality trait evolution.

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    Yanping Wang

    Full Text Available Watermelon (Citrullus lanatus (Thunb. Matsum. & Nakai is a non-climacteric fruit. The modern sweet-dessert watermelon is the result of years of cultivation and selection for fruits with desirable qualities. To date, the mechanisms of watermelon fruit ripening, and the role of abscisic acid (ABA in this process, has not been well understood. We quantified levels of free and conjugated ABA contents in the fruits of cultivated watermelon (97103; C. lanatus subsp. vulgaris, semi-wild germplasm (PI179878; C. lanatus subsp. mucosospermus, and wild germplasm (PI296341-FR; C. lanatus subsp. lanatus. Results showed that ABA content in the fruits of 97103 and PI179878 increased during fruit development and ripening, but maintained a low steady state in the center flesh of PI296341-FR fruits. ABA levels in fruits were highest in 97103 and lowest in PI296341-FR, but no obvious differences in ABA levels were observed in seeds of these lines. Examination of 31 representative watermelon accessions, including different C. lanatus subspecies and ancestral species, showed a correlation between soluble solids content (SSC and ABA levels in ripening fruits. Furthermore, injection of exogenous ABA or nordihydroguaiaretic acid (NDGA into 97103 fruits promoted or inhibited ripening, respectively. Transcriptomic analyses showed that the expression levels of several genes involved in ABA metabolism and signaling, including Cla009779 (NCED, Cla005404 (NCED, Cla020673 (CYP707A, Cla006655 (UGT and Cla020180 (SnRK2, varied significantly in cultivated and wild watermelon center flesh. Three SNPs (-738, C/A; -1681, C/T; -1832, G/T in the promoter region of Cla020673 (CYP707A and one single SNP (-701, G/A in the promoter of Cla020180 (SnRK2 exhibited a high level of correlation with SSC variation in the 100 tested accessions. Our results not only demonstrate for the first time that ABA is involved in the regulation of watermelon fruit ripening, but also provide insights into

  9. Abscisic acid pathway involved in the regulation of watermelon fruit ripening and quality trait evolution.

    Science.gov (United States)

    Wang, Yanping; Guo, Shaogui; Tian, Shouwei; Zhang, Jie; Ren, Yi; Sun, Honghe; Gong, Guoyi; Zhang, Haiying; Xu, Yong

    2017-01-01

    Watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) is a non-climacteric fruit. The modern sweet-dessert watermelon is the result of years of cultivation and selection for fruits with desirable qualities. To date, the mechanisms of watermelon fruit ripening, and the role of abscisic acid (ABA) in this process, has not been well understood. We quantified levels of free and conjugated ABA contents in the fruits of cultivated watermelon (97103; C. lanatus subsp. vulgaris), semi-wild germplasm (PI179878; C. lanatus subsp. mucosospermus), and wild germplasm (PI296341-FR; C. lanatus subsp. lanatus). Results showed that ABA content in the fruits of 97103 and PI179878 increased during fruit development and ripening, but maintained a low steady state in the center flesh of PI296341-FR fruits. ABA levels in fruits were highest in 97103 and lowest in PI296341-FR, but no obvious differences in ABA levels were observed in seeds of these lines. Examination of 31 representative watermelon accessions, including different C. lanatus subspecies and ancestral species, showed a correlation between soluble solids content (SSC) and ABA levels in ripening fruits. Furthermore, injection of exogenous ABA or nordihydroguaiaretic acid (NDGA) into 97103 fruits promoted or inhibited ripening, respectively. Transcriptomic analyses showed that the expression levels of several genes involved in ABA metabolism and signaling, including Cla009779 (NCED), Cla005404 (NCED), Cla020673 (CYP707A), Cla006655 (UGT) and Cla020180 (SnRK2), varied significantly in cultivated and wild watermelon center flesh. Three SNPs (-738, C/A; -1681, C/T; -1832, G/T) in the promoter region of Cla020673 (CYP707A) and one single SNP (-701, G/A) in the promoter of Cla020180 (SnRK2) exhibited a high level of correlation with SSC variation in the 100 tested accessions. Our results not only demonstrate for the first time that ABA is involved in the regulation of watermelon fruit ripening, but also provide insights into the

  10. Interaction of Polyamines, Abscisic Acid, Nitric Oxide, and Hydrogen Peroxide under Chilling Stress in Tomato (Lycopersicon esculentum Mill.) Seedlings

    OpenAIRE

    Diao, Qiannan; Song, Yongjun; Shi, Dongmei; Qi, Hongyan

    2017-01-01

    Polyamines (PAs) play a vital role in the responses of higher plants to abiotic stresses. However, only a limited number of studies have examined the interplay between PAs and signal molecules. The aim of this study was to elucidate the cross-talk among PAs, abscisic acid (ABA), nitric oxide (NO), and hydrogen peroxide (H2O2) under chilling stress conditions using tomato seedlings [(Lycopersicon esculentum Mill.) cv. Moneymaker]. The study showed that during chilling stress (4°C; 0, 12, and 2...

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

    DEFF Research Database (Denmark)

    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...... but involves direct cyclization of farnesyl diphosphate and subsequent oxidation steps. We present here evidence that this "direct" pathway is indeed the only one used by an ABA-overproducing strain of B. cinerea. Targeted inactivation of the gene bccpr1 encoding a cytochrome P450 oxidoreductase reduced...

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

    Czech Academy of Sciences Publication Activity Database

    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

  13. The role of zeatin and gibberellic acid in breaking of the abscisic acid-induced dormancy in Triticale caryopses

    Directory of Open Access Journals (Sweden)

    Stanisław Weidner

    2014-01-01

    Full Text Available The investigations were conducted on the germinating embryos and the whole caryopses of Triticale. During preimbibition and 24 hours germination caryopses were treated with abscisic acid (ABA, which produced 63% inhibition of embryo growth. Gibberellin-A3 (GA3 reversed the ABA effect in 18%, while zeatin in 22%. The clear synergic reaction was observed (36% when both stimulators acted together. There was no significant effect of ABA, ABA and GA3, as well as ABA and zeatin on the synthesis of polyribosomal RNA in the initial period of germination of excised embryos. However, during 24 hours germination of whole caryopses ABA caused a twofold decrease in 3H-uridine incorporation into the total fraction of embryonic ribosomes. While the incorporation of 14C-aminoacid mixture into ribosomal proteins was even three-fold lower. Effect of GA3 and zeatin on breaking of the ABA-induced "dormancy" was studied. It was confirmed that the higher polyribosome contribution to the sum total of ribosomes the more intensive synthesis of ribosomal proteins. No higher 3H-uridine incorporation into polyribosomal fraction was observed. From the results it may be inferred that in the initial period of germination of Triticale caryopses regulation of protein biosynthesis occurs rather at the translation than transcription level.

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

    KAUST Repository

    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.

  15. Genomic profiling of exogenous abscisic acid-responsive microRNAs in tomato (Solanum lycopersicum).

    Science.gov (United States)

    Cheng, Hai-Yang; Wang, Yan; Tao, Xiang; Fan, Yan-Fen; Dai, Ya; Yang, Hong; Ma, Xin-Rong

    2016-06-03

    Plant microRNAs (miRNAs) are involved in various biological pathways and stress responses as negative regulators at the posttranscriptional level. Abscisic acid (ABA) is a key signaling molecule that mediates plant stress response by activating many stress-related genes. Although some miRNAs in plants are previously identified to respond to ABA, a comprehensive profile of ABA-responsive miRNAs has not yet been elucidated. Here, we identified miRNAs responding to exogenous application of ABA, and their predicted target genes in the model plant organism tomato (Solanum lycopersicum). Deep sequencing of small RNAs from ABA-treated and untreated tomatoes revealed that miRNAs can be up- or down-regulated upon treatment with ABA. A total of 1067 miRNAs were detected (including 365 known and 702 candidate novel miRNAs), of those, 416 miRNAs which had an abundance over two TPM (transcripts per million) were selected for differential expression analysis. We identified 269 (180 known and 89 novel) miRNAs that respond to exogenous ABA treatment with a change in expression level of |log2FC|≥0.25. 136 of these miRNAs (90 known and 46 novel) were expressed at significantly different levels |log2FC|≥1 between treatments. Furthermore, stem-loop RT-PCR was applied to validate the RNA-seq data. Target prediction and analysis of the corresponding ABA-responsive transcriptome data uncovered that differentially expressed miRNAs are involved in condition stress and pathogen resistance, growth and development. Among them, approximately 90 miRNAs were predicted to target transcription factors and pathogen resistance genes. Some miRNAs had functional overlap in biotic and abiotic stress. Most of these miRNAs were down-regulated following exposure to exogenous ABA, while their related target genes were inversely up-regulated, which is consistent with their negative regulatory role in gene expression. Exogenous ABA application influences the composition and expression level of tomato mi

  16. Transcriptional regulatory programs underlying barley germination and regulatory functions of Gibberellin and abscisic acid

    Science.gov (United States)

    2011-01-01

    Background Seed germination is a complex multi-stage developmental process, and mainly accomplished through concerted activities of many gene products and biological pathways that are often subjected to strict developmental regulation. Gibberellins (GA) and abscisic acid (ABA) are two key phytohormones regulating seed germination and seedling growth. However, transcriptional regulatory networks underlying seed germination and its associated biological pathways are largely unknown. Results The studies examined transcriptomes of barley representing six distinct and well characterized germination stages and revealed that the transcriptional regulatory program underlying barley germination was composed of early, late, and post-germination phases. Each phase was accompanied with transcriptional up-regulation of distinct biological pathways. Cell wall synthesis and regulatory components including transcription factors, signaling and post-translational modification components were specifically and transiently up-regulated in early germination phase while histone families and many metabolic pathways were up-regulated in late germination phase. Photosynthesis and seed reserve mobilization pathways were up-regulated in post-germination phase. However, stress related pathways and seed storage proteins were suppressed through the entire course of germination. A set of genes were transiently up-regulated within three hours of imbibition, and might play roles in initiating biological pathways involved in seed germination. However, highly abundant transcripts in dry barley and Arabidopsis seeds were significantly conserved. Comparison with transcriptomes of barley aleurone in response to GA and ABA identified three sets of germination responsive genes that were regulated coordinately by GA, antagonistically by ABA, and coordinately by GA but antagonistically by ABA. Major CHO metabolism, cell wall degradation and protein degradation pathways were up-regulated by both GA and seed

  17. Arabidopsis seed-specific vacuolar aquaporins are involved in maintaining seed longevity under the control of ABSCISIC ACID INSENSITIVE 3.

    Science.gov (United States)

    Mao, Zhilei; Sun, Weining

    2015-08-01

    The tonoplast intrinsic proteins TIP3;1 and TIP3;2 are specifically expressed during seed maturation and localized to the seed protein storage vacuole membrane. However, the function and physiological roles of TIP3s are still largely unknown. The seed performance of TIP3 knockdown mutants was analysed using the controlled deterioration test. The tip3;1/tip3;2 double mutant was affected in seed longevity and accumulated high levels of hydrogen peroxide compared with the wild type, suggesting that TIP3s function in seed longevity. The transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3) is known to be involved in seed desiccation tolerance and seed longevity. TIP3 transcript and protein levels were significantly reduced in abi3-6 mutant seeds. TIP3;1 and TIP3;2 promoters could be activated by ABI3 in the presence of abscisic acid (ABA) in Arabidopsis protoplasts. TIP3 proteins were detected in the protoplasts transiently expressing ABI3 and in ABI3-overexpressing seedlings when treated with ABA. Furthermore, ABI3 directly binds to the RY motif of the TIP3 promoters. Therefore, seed-specific TIP3s may help maintain seed longevity under the expressional control of ABI3 during seed maturation and are members of the ABI3-mediated seed longevity pathway together with small heat shock proteins and late embryo abundant proteins. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. Detection of phytohormones in temperate forest fungi predicts consistent abscisic acid production and a common pathway for cytokinin biosynthesis.

    Science.gov (United States)

    Morrison, Erin N; Knowles, Sarah; Hayward, Allison; Thorn, R Greg; Saville, Barry J; Emery, R J N

    2015-01-01

    The phytohormones, abscisic acid and cytokinin, once were thought to be present uniquely in plants, but increasing evidence suggests that these hormones are present in a wide variety of organisms. Few studies have examined fungi for the presence of these "plant" hormones or addressed whether their levels differ based on the nutrition mode of the fungus. This study examined 20 temperate forest fungi of differing nutritional modes (ectomycorrhizal, wood-rotting, saprotrophic). Abscisic acid and cytokinin were present in all fungi sampled; this indicated that the sampled fungi have the capacity to synthesize these two classes of phytohormones. Of the 27 cytokinins analyzed by HPLC-ESI MS/MS, seven were present in all fungi sampled. This suggested the existence of a common cytokinin metabolic pathway in fungi that does not vary among different nutritional modes. Predictions regarding the source of isopentenyl, cis-zeatin and methylthiol CK production stemming from the tRNA degradation pathway among fungi are discussed. © 2015 by The Mycological Society of America.

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

    Science.gov (United States)

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

    2016-01-01

    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

  20. [The ABC of abscisic acid action in plant drought stress responses].

    Science.gov (United States)

    Leung, Jeffrey; Valon, Christiane; Moreau, Bertrand; Boeglin, Martin; Lefoulon, Cécile; Joshi-Saha, Archana; Chérel, Isabelle

    2012-01-01

    The combined daily consumption of fresh water ranges from 200 to 700 liters per capita per day in most developed countries, with about 70% being used for agricultural needs. Unlike other resources such as the different forms of energy, water has no other alternatives. With the looming prospect of global water crisis, the recent laudable success in deciphering the early steps in the signal transduction of the "stress hormone" abscisic acid (ABA) has ignited hopes that crops can be engineered with the capacity to maintain productivity while requiring less water input. Although ABA was first discovered in plants, it has resurfaced in the human brain (and many other non-plant organisms : sea sponge, some parasites, hydra to name a few), suggesting that its existence may be widespread. In humans, more amazingly, ABA has shown anti-inflammatory and antiviral properties. Even its receptors and key signaling intermediates have homologs in the human genome suggesting that evolution has re-fashioned these same proteins into new functional contexts. Thus, learning about the molecular mechanisms of ABA in action using the more flexible plant model will be likely beneficial to other organisms, and especially in human diseases, which is topical in the medical circle. ABA can accumulate up to 10 to 30-fold in plants under drought stress relative to unstressed conditions. The built up of the hormone then triggers diverse adaptive pathways permitting plants to withstand temporary bouts of water shortage. One favorite experimental model to unravel ABA signaling mechanisms in all of its intimate detail is based on the hormone's ability to elicit stomatal closure - a rapid cellular response of land plants to limit water loss through transpiration. Each microscopic stoma, or pore, is contoured by two specialized kidney-shaped cells called the guard cells. Because land plants are protected by a waxy cuticle impermeable to gas exchange, the stomatal pores are thus the primary portals for

  1. Abscisic acid metabolite profiling as indicators of plastic responses to drought in grasses from arid Patagonian Monte (Argentina).

    Science.gov (United States)

    Cenzano, Ana M; Masciarelli, O; Luna, M Virginia

    2014-10-01

    The identification of hormonal and biochemical traits that play functional roles in the adaptation to drought is necessary for the conservation and planning of rangeland management. The aim of this study was to evaluate the effects of drought on i) the water content (WC) of different plant organs, ii) the endogenous level of abscisic acid (ABA) and metabolites (phaseic acid-PA, dihydrophaseic acid-DPA and abscisic acid conjugated with glucose ester-ABA-GE), iii) the total carotenoid concentration and iv) to compare the traits of two desert perennial grasses (Pappostipa speciosa and Poa ligularis) with contrasting morphological and functional drought resistance traits and life-history strategies. Both species were subjected to two levels of gravimetric soil moisture (the highest near field capacity during autumn-winter and the lowest corresponding to summer drought). Drought significantly increased the ABA and DPA levels in the green leaves of P. speciosa and P. ligularis. Drought decreased ABA in the roots of P. speciosa while it increased ABA in the roots of P. ligularis. P. ligularis had the highest ABA level and WC in green leaves. While P. speciosa had the highest DPA levels in leaves. In conclusion, we found the highest ABA level in the mesophytic species P. ligularis and the lowest ABA level in the xerophytic species P. speciosa, revealing that the ABA metabolite profile in each grass species is a plastic response to drought resistance. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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. Effect of Exogenous Abscisic Acid and Methyl Jasmonate on Anthocyanin Composition, Fatty Acids, and Volatile Compounds of Cabernet Sauvignon (Vitis vinifera L.) Grape Berries.

    Science.gov (United States)

    Ju, Yan-Lun; Liu, Min; Zhao, Hui; Meng, Jiang-Fei; Fang, Yu-Lin

    2016-10-12

    The anthocyanin composition, fatty acids, and volatile aromas are important for Cabernet Sauvignon grape quality. This study evaluated the effect of exogenous abscisic acid (ABA) and methyl jasmonate (MeJA) on the anthocyanin composition, fatty acids, lipoxygenase activity, and the volatile compounds of Cabernet Sauvignon grape berries. Exogenous ABA and MeJA improved the content of total anthocyanins (TAC) and individual anthocyanins. Lipoxygenase (LOX) activity also increased after treatment. Furthermore, 16 fatty acids were detected. The linoleic acid concentration gradually increased with ABA concentration. The fatty acid content decreased with increasing MeJA concentration and then increased again, with the exception of linoleic acid. After exogenous ABA and MeJA treatment, the C6 aroma content increased significantly. Interestingly, the exogenous ABA and MeJA treatments improved mainly the content of 1-hexanol, hexanal, and 2-heptanol. These results provide insight into the effect of plant hormones on wine grapes, which is useful for grape quality improvement.

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

    Czech Academy of Sciences Publication Activity Database

    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

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

    Science.gov (United States)

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

    2016-01-01

    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

  6. A New Approach to Sequence Analysis Exemplified by Identification of cis-Elements in Abscisic Acid Inducible Promoters

    DEFF Research Database (Denmark)

    Busk, Peter Kamp; Hallin, Peter Fischer; Salomon, Jesper

    the sequences of known cis-elements for promoter prediction4. This is a computational alternative to genome-wide DNA array analysis of gene expression and can be used to confirm the importance of known promoter elements on a genome level. Unfortunately, this approach does not yield information about new cis....... These promoters were compared to 28000 promoters that are not induced by abscisic acid. The analysis identified previously described ABA-inducible promoter elements such as ABRE, CE3 and CRT1 but also new cis-elements were found. Furthermore, the list of DNA elements could be used to predict ABA......-inducible promoter with more than 70 % accuracy for the top 40 predictions, which is better than previously described methods4. In conclusion, identification of short, conserved motifs is a useful computational approach for identification of cis-elements in DNA promoters and for promoter prediction in genome...

  7. Functional characterization of a synthetic abscisic acid analog with anti-inflammatory activity on human granulocytes and monocytes.

    Science.gov (United States)

    Grozio, Alessia; Millo, Enrico; Guida, Lucrezia; Vigliarolo, Tiziana; Bellotti, Marta; Salis, Annalisa; Fresia, Chiara; Sturla, Laura; Magnone, Mirko; Galatini, Andrea; Damonte, Gianluca; De Flora, Antonio; Bruzzone, Santina; Bagnasco, Luca; Zocchi, Elena

    2011-12-02

    The phytohormone abscisic acid (ABA), in addition to regulating several important physiological functions in plants, is also produced and released by human granulocytes and monocytes where it stimulates cell activities involved in the innate immune response. Here we describe the properties of an ABA synthetic analog that competes with the hormone for binding to human granulocyte membranes and to purified recombinant LANCL2 (the human ABA receptor) and inhibits several ABA-triggered inflammatory functions of granulocytes and monocytes in vitro: chemotaxis, phagocytosis, reactive oxygen species production and release of prostaglandin E(2) (PGE(2)) by human granulocytes, release of PGE(2) and of monocyte chemoattractant protein-1 by human monocytes. This observation provides a proof of principle that ABA antagonists may represent a new class of anti-inflammatory agents. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Surviving a Dry Future: Abscisic Acid (ABA-Mediated Plant Mechanisms for Conserving Water under Low Humidity

    Directory of Open Access Journals (Sweden)

    Frances C. Sussmilch

    2017-11-01

    Full Text Available Angiosperms are able to respond rapidly to the first sign of dry conditions, a decrease in air humidity, more accurately described as an increase in the vapor pressure deficit between the leaf and the atmosphere (VPD, by abscisic acid (ABA-mediated stomatal closure. The genes underlying this response offer valuable candidates for targeted selection of crop varieties with improved drought tolerance, a critical goal for current plant breeding programs, to maximize crop production in drier and increasingly marginalized environments, and meet the demands of a growing population in the face of a changing climate. Here, we review current understanding of the genetic mechanisms underpinning ABA-mediated stomatal closure, a key means for conserving water under dry conditions, examine how these mechanisms evolved, and discuss what remains to be investigated.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. α-Ketol linolenic acid (KODA) application affects endogenous abscisic acid, jasmonic acid and aromatic volatiles in grapes infected by a pathogen (Glomerella cingulata).

    Science.gov (United States)

    Wang, Shanshan; Saito, Takanori; Ohkawa, Katsuya; Ohara, Hitoshi; Shishido, Masahiro; Ikeura, Hiromi; Takagi, Kazuteru; Ogawa, Shigeyuki; Yokoyama, Mineyuki; Kondo, Satoru

    2016-03-15

    Effects of α-ketol linolenic acid (KODA) application on endogenous abscisic acid (ABA), jasmonic acid (JA), and aromatic volatiles were investigated in 'Kyoho' grapes (Vitis labrusca×Vitis vinifera) infected by a pathogen (Glomerella cingulata). The expressions of 9-cis-epoxycarotenoid dioxygenase (VvNCED1), ABA 8'-hydroxylase (VvCYP707A1), lipoxygenase (VvLOX), and allene oxide synthase (VvAOS) were also examined. The grape berries were dipped in 0.1mM KODA solution before inoculation with the pathogen and stored at 25°C for 12 days. The development of infection was significantly suppressed upon KODA treatment. Endogenous ABA, JA and phaseic acid (PA) were induced in inoculated berries. KODA application before inoculation increased endogenous ABA, PA and JA through the activation of VvNCED1, VvCYP707A1 and VvAOS genes, respectively. In addition, terpenes, methyl salicylate (Me-SA) and C6-aldehydes such as (E)-2-hexenal and cis-3-hexenal associated with fungal resistance also increased in KODA-treated berries during storage. These results suggest that the synergistic effect of JA, ABA, and some aromatic volatiles induced by KODA application may provide resistance to pathogen infection in grape berries. Copyright © 2016 Elsevier GmbH. All rights reserved.

  12. Flower inhibition in Kalanchoe blossfeldiana. Bioassay of an endogenous long-day inhibitor and inhibition by (±) abscisic acid and xanthoxin.

    Science.gov (United States)

    Schwabe, W W

    1972-03-01

    The inhibition of flowering in Kalanchoe by crude sap expressed from leaves held in non-inductive long-day conditions is described, using a bioassay technique of leaf injection, which confirms the existence of a transferable inhibitor.This technique has also revealed that ± abscisic acid and Xanthoxin are inhibitory to flowering at 50 and 100 ppm respectively. The previously known inhibitory effects of gibberellic acid on flowering have also been confirmed.

  13. Development of an ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous determination of salicylic acid, jasmonic acid, and abscisic acid in rose leaves.

    Science.gov (United States)

    Bosco, Renato; Daeseleire, Els; Van Pamel, Els; Scariot, Valentina; Leus, Leen

    2014-07-09

    This paper describes a method to detect and quantitate the endogenous plant hormones (±)-2-cis-4-trans-abscisic acid, (-)-jasmonic acid, and salicylic acid by means of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in hybrid rose leaf matrices. Deuterium-labeled [(2)H6] (+)-2-cis-4-trans-abscisic acid, [(2)H6] (±)-jasmonic acid, and [(2)H4]-salicylic acid were used as internal standards. Rose samples (10 mg) were extracted with methanol/water/acetic acid (10:89:1) and subsequently purified on an Oasis MCX 1 cm(3) Vac SPE cartridge. Performance characteristics were validated according to Commission Decision 2002/657/EC. Recovery, repeatability, and within-laboratory reproducibility were acceptable for all phytohormones tested at three different concentrations. The decision limit and detection capability for (±)-2-cis-4-trans-abscisic acid, (-)-jasmonic acid, and salicylic acid were 0.0075 and 0.015 μg/g, 0.00015 and 0.00030 μg/g, and 0.0089 and 0.018 μg/g, respectively. Matrix effects (signal suppression or enhancement) appeared to be high for all substances considered, implying the need for quantitation based on matrix-matched calibration curves.

  14. Sustained exposure to abscisic acid enhances the colonization potential of the mutualist fungus Piriformospora indica on Arabidopsis thaliana roots.

    Science.gov (United States)

    Peskan-Berghöfer, Tatjana; Vilches-Barro, Amaya; Müller, Teresa M; Glawischnig, Erich; Reichelt, Michael; Gershenzon, Jonathan; Rausch, Thomas

    2015-11-01

    Root colonization by the beneficial fungus Piriformospora indica is controlled by plant innate immunity, but factors that channel this interaction into a mutualistic relationship are not known. We have explored the impact of abscisic acid (ABA) and osmotic stress on the P. indica interaction with Arabidopsis thaliana. The activation of plant innate immunity in roots was determined by measuring the concentration of the phytoalexin camalexin and expression of transcription factors regulating the biosynthesis of tryptophan-related defence metabolites. Furthermore, the impact of the fungus on the content of ABA, salicylic acid, jasmonic acid (JA) and JA-related metabolites was examined. We demonstrated that treatment with exogenous ABA or the ABA analogue pyrabactin increased fungal colonization efficiency without impairment of plant fitness. Concomitantly, ABA-deficient mutants of A. thaliana (aba1-6 and aba2-1) were less colonized, while plants exposed to moderate stress were more colonized than corresponding controls. Sustained exposure to ABA attenuated expression of transcription factors MYB51, MYB122 and WRKY33 in roots upon P. indica challenge or chitin treatment, and prevented an increase in camalexin content. The results indicate that ABA can strengthen the interaction with P. indica as a consequence of its impact on plant innate immunity. Consequently, ABA will be relevant for the establishment and outcome of the symbiosis under stress conditions. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  15. Somatic embryogenesis in loblolly pine (Pinus taeda L.): improving culture initiation with abscisic acid and silver nitrate.

    Science.gov (United States)

    Pullman, G S; Namjoshi, K; Zhang, Y

    2003-09-01

    Loblolly pine ( Pinus taeda L.) culture initiation was improved by the addition of abscisic acid (ABA) (3.7 micro M), silver nitrate (20 micro M), and guanosine 3',5'-cyclic monophosphate, 8-bromo-, sodium salt (10 micro M) to the medium and by raising cytokinin levels in the presence of 50 mg/l activated carbon (AC). Basal medium contained modified 1/2-P6 salts, 50 mg/l AC, Cu and Zn added to compensate for adsorption by AC, 1.5% maltose, 2% myo-inositol, 500 mg/l casamino acids, 450 mg/l glutamine, 2 mg/l alpha-naphthaleneacetic acid (NAA), 0.55 mg/l 6-benzylaminopurine (BA), 0.53 mg/l kinetin, and 2 g/l Gelrite. Across 32 open-pollinated families initiation ranged from 0 to 53.4%, with an average of 17.9%. Further optimization of cytokinins to 0.63 mg/l BA and 0.61 mg/l kinetin along with the removal of ABA maintained initiation at 18.2% across 19 families. Survival of 2001 new initiations was tracked for 4-6 months. Survival averaged 28.8%. A test of 68 new initiations tracked closely for 4 months demonstrated that at least 80% of the cultures lost did not grow after transfer to the multiplication media, suggesting that many new initiations abort during the initiation process.

  16. P-HYDROXYPHENYLPYRUVATE DIOXYGENASE from Medicago sativa is involved in vitamin E biosynthesis and abscisic acid-mediated seed germination

    Science.gov (United States)

    Jiang, Jishan; Chen, Zhihong; Ban, Liping; Wu, Yudi; Huang, Jianping; Chu, Jinfang; Fang, Shuang; Wang, Zan; Gao, Hongwen; Wang, Xuemin

    2017-01-01

    P-HYDROXYPHENYLPYRUVATE DIOXYGENASE (HPPD) is the first committed enzyme involved in the biosynthesis of vitamin E, and is characterized by catalyzing the conversion of p-hydroxyphenyl pyruvate (HPP) to homogentisic acid (HGA). Here, an HPPD gene was cloned from Medicago sativa L. and designated MsHPPD, which was expressed at high levels in alfalfa leaves. PEG 6000 (polyethylene glycol), NaCl, abscisic acid and salicylic acid were shown to significantly induce MsHPPD expression, especially in the cotyledons and root tissues. Overexpression of MsHPPD was found to significantly increase the level of β-tocotrienol and the total vitamin E content in Arabidopsis seeds. Furthermore, these transgenic Arabidopsis seeds exhibited an accelerated germination time, compared with wild-type seeds under normal conditions, as well as under NaCl and ABA treatments. Meanwhile, the expression level of several genes associated with ABA biosynthesis (NCED3, NCED5 and NCED9) and the ABA signaling pathway (RAB18, ABI3 and ABI5) were significantly down-regulated in MsHPPD-overexpressing transgenic lines, as well as the total free ABA content. Taken together, these results demonstrate that MsHPPD functions not only in the vitamin E biosynthetic pathway, but also plays a critical role in seed germination via affecting ABA biosynthesis and signaling. PMID:28084442

  17. P-HYDROXYPHENYLPYRUVATE DIOXYGENASE from Medicago sativa is involved in vitamin E biosynthesis and abscisic acid-mediated seed germination.

    Science.gov (United States)

    Jiang, Jishan; Chen, Zhihong; Ban, Liping; Wu, Yudi; Huang, Jianping; Chu, Jinfang; Fang, Shuang; Wang, Zan; Gao, Hongwen; Wang, Xuemin

    2017-01-13

    P-HYDROXYPHENYLPYRUVATE DIOXYGENASE (HPPD) is the first committed enzyme involved in the biosynthesis of vitamin E, and is characterized by catalyzing the conversion of p-hydroxyphenyl pyruvate (HPP) to homogentisic acid (HGA). Here, an HPPD gene was cloned from Medicago sativa L. and designated MsHPPD, which was expressed at high levels in alfalfa leaves. PEG 6000 (polyethylene glycol), NaCl, abscisic acid and salicylic acid were shown to significantly induce MsHPPD expression, especially in the cotyledons and root tissues. Overexpression of MsHPPD was found to significantly increase the level of β-tocotrienol and the total vitamin E content in Arabidopsis seeds. Furthermore, these transgenic Arabidopsis seeds exhibited an accelerated germination time, compared with wild-type seeds under normal conditions, as well as under NaCl and ABA treatments. Meanwhile, the expression level of several genes associated with ABA biosynthesis (NCED3, NCED5 and NCED9) and the ABA signaling pathway (RAB18, ABI3 and ABI5) were significantly down-regulated in MsHPPD-overexpressing transgenic lines, as well as the total free ABA content. Taken together, these results demonstrate that MsHPPD functions not only in the vitamin E biosynthetic pathway, but also plays a critical role in seed germination via affecting ABA biosynthesis and signaling.

  18. Proteome analysis of Norway maple (Acer platanoides L. seeds dormancy breaking and germination: influence of abscisic and gibberellic acids

    Directory of Open Access Journals (Sweden)

    Pawłowski Tomasz A

    2009-05-01

    Full Text Available Abstract Background Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid and growth promoters (e.g. gibberellins is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process. Results A proteomic approach was used to analyse the mechanism of dormancy breaking in Norway maple seeds caused by cold stratification, and the participation of the abscisic (ABA and gibberellic (GA acids. Forty-four proteins showing significant changes were identified by mass spectrometry. Of these, eight spots were identified as water-responsive, 18 spots were ABA- and nine GA-responsive and nine spots were regulated by both hormones. The classification of proteins showed that most of the proteins associated with dormancy breaking in water were involved in protein destination. Most of the ABA- and GA-responsive proteins were involved in protein destination and energy metabolism. Conclusion In this study, ABA was found to mostly down-regulate proteins whereas GA up-regulated proteins abundance. Most of the changes were observed at the end of stratification in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent

  19. Conservation between higher plants and the moss Physcomitrella patens in response to the phytohormone abscisic acid: a proteomics analysis

    Directory of Open Access Journals (Sweden)

    Wang Xiaoqin

    2010-08-01

    Full Text Available Abstract Background The plant hormone abscisic acid (ABA is ubiquitous among land plants where it plays an important role in plant growth and development. In seeds, ABA induces embryogenesis and seed maturation as well as seed dormancy and germination. In vegetative tissues, ABA is a necessary mediator in the triggering of many of the physiological and molecular adaptive responses of the plant to adverse environmental conditions, such as desiccation, salt and cold. Results In this study, we investigated the influence of abscisic acid (ABA on Physcomitrella patens at the level of the proteome using two-dimensional gel electrophoresis (2-DE and liquid chromatography-tandem mass spectrometry (LC-MS/MS. Sixty-five protein spots showed changes in response to ABA treatment. Among them, thirteen protein spots were down-regulated; fifty-two protein spots were up-regulated including four protein spots which were newly induced. These proteins were involved in various functions, including material and energy metabolism, defense, protein destination and storage, transcription, signal transduction, cell growth/division, transport, and cytoskeleton. Specifically, most of the up-regulated proteins functioned as molecular chaperones, transcriptional regulators, and defense proteins. Detailed analysis of these up-regulated proteins showed that ABA could trigger stress and defense responses and protect plants from oxidative damage. Otherwise, three protein kinases involved in signal pathways were up-regulated suggesting that P. patens is sensitive to exogenous ABA. The down-regulated of the Rubisco small subunit, photosystem II oxygen-evolving complex proteins and photosystem assembly protein ycf3 indicated that photosynthesis of P. patens was inhibited by ABA treatment. Conclusion Proteome analysis techniques have been applied as a direct, effective, and reliable tool in differential protein expressions. Sixty-five protein spots showed differences in

  20. Mutations in the Arabidopsis Lst8 and Raptor genes encoding partners of the TOR complex, or inhibition of TOR activity decrease abscisic acid (ABA) synthesis.

    Science.gov (United States)

    Kravchenko, Alena; Citerne, Sylvie; Jéhanno, Isabelle; Bersimbaev, Rakhmetkazhi I; Veit, Bruce; Meyer, Christian; Leprince, Anne-Sophie

    2015-11-27

    The Target of Rapamycin (TOR) kinase regulates essential processes in plant growth and development by modulation of metabolism and translation in response to environmental signals. In this study, we show that abscisic acid (ABA) metabolism is also regulated by the TOR kinase. Indeed ABA hormone level strongly decreases in Lst8-1 and Raptor3g mutant lines as well as in wild-type (WT) Arabidopsis plants treated with AZD-8055, a TOR inhibitor. However the growth and germination of these lines are more sensitive to exogenous ABA. The diminished ABA hormone accumulation is correlated with lower transcript levels of ZEP, NCED3 and AAO3 biosynthetic enzymes, and higher transcript amount of the CYP707A2 gene encoding a key-enzyme in abscisic acid catabolism. These results suggest that the TOR signaling pathway is implicated in the regulation of ABA accumulation in Arabidopsis. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. 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

    Directory of Open Access Journals (Sweden)

    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.

  2. Effect of the winter wheat cheyenne 5A substituted chromosome on dynamics of abscisic acid and cytokinins in freezing-sensitive Chinese spring genetic background

    Czech Academy of Sciences Publication Activity Database

    Kalapos, S.; Novák, A.; Dobrev, Petre; Vítámvás, P.; Marincs, F.; Galiba, G.; Vaňková, Radomíra

    2017-01-01

    Roč. 8, NOV 29 (2017), č. článku 2033. ISSN 1664-462X R&D Projects: GA ČR(CZ) GA17-06613S; GA MZe QJ1530373 Institutional support: RVO:61389030 Keywords : Abscisic acid * Cold treatment * Cytokinin * Freezing tolerance * Gene expression * Phytohormones * Triticum aestivum Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 4.298, year: 2016

  3. Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress

    OpenAIRE

    Chen Zhixiang; Xiao Yong; Shi Junwei; Lai Zhibing; Chen Han; Xu Xinping

    2010-01-01

    Abstract Background WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. Results We report that the three WRKYs are involved in plant responses to abscisic acid (ABA) and abiotic stress. Through analysis of single, double, and triple muta...

  4. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance

    OpenAIRE

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

    2016-01-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana. Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure...

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

    Czech Academy of Sciences Publication Activity Database

    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 - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : Nannochloropsis oceanica * antagonistic synergy * abscisic acid Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.972, year: 2014

  6. The ratio of red light to far red light alters Arabidopsis axillary bud growth and abscisic acid signalling before stem auxin changes

    OpenAIRE

    Holalu, Srinidhi V.; Finlayson, Scott A.

    2017-01-01

    Abstract Arabidopsis thaliana shoot branching is inhibited by a low red light to far red light ratio (R:FR, an indicator of competition), and by loss of phytochrome B function. Prior studies have shown that phytochrome B deficiency suppresses bud growth by elevating systemic auxin signalling, and that increasing the R:FR promotes the growth of buds suppressed by low R:FR by inhibiting bud abscisic acid (ABA) accumulation and signalling. Here, systemic auxin signalling and bud ABA signalling w...

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

    Czech Academy of Sciences Publication Activity Database

    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

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

    Science.gov (United States)

    Li, Dongdong; Li, Li; Luo, Zisheng; Mou, Wangshu; Mao, Linchun; Ying, Tiejin

    2015-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Crystallization of the plant hormone receptors PYL9/RCAR1, PYL5/RCAR8 and PYR1/RCAR11 in the presence of (+)-abscisic acid

    International Nuclear Information System (INIS)

    Shibata, Nobuyuki; Kagiyama, Megumi; Nakagawa, Masahiro; Hirano, Yoshinori; Hakoshima, Toshio

    2010-01-01

    Crystals of the Arabidopsis abscisic acid receptors PYL9/RCAR1, PYL5/RCAR8 and PYR1/RCAR11 have been obtained. Abscisic acid (ABA) is a plant hormone that plays key regulatory roles in physiological pathways for the adaptation of vegetative tissues to abiotic stresses such as water stress in addition to events pertaining to plant growth and development. The Arabidopsis ABA receptor proteins PYR/PYLs/RCARs form a START family that contains 14 members which are classified into three subfamilies (I–III). Here, purification, crystallization and X-ray data collection are reported for a member of each of the subfamilies, PYL9/RCAR1 from subfamily I, PYL5/RCAR8 from subfamily II and PYR1/RCAR11 from subfamily III, in the presence of (+)-abscisic acid. The three proteins crystallize in space groups P3 1 21/P3 2 21, P2 and P1, respectively. X-ray intensity data were collected to 1.9–2.6 Å resolution

  11. Quantification of abscisic acid in grapevine leaf (Vitis vinifera) by isotope-dilution liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Vilaró, Francisca; Canela-Xandri, Anna; Canela, Ramon

    2006-09-01

    A specific, sensitive, precise, and accurate method for the determination of abscisic acid (ABA) in grapevine leaf tissues is described. The method employs high-performance liquid chromatography and electrospray ionization-mass spectrometry (LC-ESI-MS) in selected ion monitoring mode (SIM) to analyze ABA using a stable isotope-labeled ABA as an internal standard. Absolute recoveries ranged from 72% to 79% using methanol/water pH 5.5 (50:50 v/v) as an extraction solvent. The best efficiency was obtained when the chromatographic separation was carried out by using a porous graphitic carbon (PGC) column. The statistical evaluation of the method was satisfactory in the work range. A relative standard deviation (RDS) of < 5.5% and < 6.0% was obtained for intra-batch and inter-batch comparisons, respectively. As for accuracy, the relative error (%Er) was between -2.7 and 4.3%, and the relative recovery ranged from 95% to 107%.

  12. Chloroplast protein PLGG1 is involved in abscisic acid-regulated lateral root development and stomatal movement in Arabidopsis.

    Science.gov (United States)

    Dong, Huan; Bai, Ling; Chang, Jie; Song, Chun-Peng

    2018-01-01

    The plant hormone abscisic acid (ABA) plays a crucial role in root architecture; however, the molecular mechanism of ABA-regulated lateral root (LR) growth is not well known. We screened an Arabidopsis thaliana mutant with LR growth that was sensitive to ABA from a T-DNA insertion mutant library, which was an allelic mutant of plgg1-1, termed plgg1-2. PLGG1 encodes a chloroplast protein that transports plastidic glycolate and glycerate. The length and number of LRs at the root-hypocotyl junction of plgg1-1 and plgg1-2 were significantly impaired under exogenous ABA treatment, and the transgenic plant complementary lines of plgg1-2 restored LR growth in response to ABA. In addition, we found that PLGG1 is involved in other major ABA responses, including ABA-inhibited seed germination, ABA-mediated stomatal movement, and drought tolerance. These findings open new perspectives on elucidating the mechanism of ABA response, and provide clues for analysing the functions of chloroplast proteins in regulating root growth. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Abscisic Acid content of senescing petals on cut rose flowers as affected by sucrose and water stress.

    Science.gov (United States)

    Borohov, A; Tirosh, T; Halevy, A H

    1976-08-01

    Leafless cut Superstar roses (Rosa hyb.) were kept in a 1% sucrose solution. During the first few days of treatment, the abscisic acid content and the water deficit in the petals was higher in treated flowers than in controls kept in water. Later and up to the termination of the flower's life, ABA content and water deficit values were lower in petals of sucrose-treated flowers than in controls. Water stress treatments resulted in higher water deficit values and higher ABA content of petals. An 8-day sucrose treatment following temporary water stress improved the quality of flowers and reduced the level of ABA in the petals. We conclude that the effect which sucrose has on the ABA content of rose petals is at least partly due to its effect on changes in water deficit in the petals. This happens in spite of the fact that rose petals have no stomata, and therefore, ABA is not involved in regulating water balance via the stomata.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. An Alfin-like gene from Atriplex hortensis enhances salt and drought tolerance and abscisic acid response in transgenic Arabidopsis.

    Science.gov (United States)

    Tao, Jian-Jun; Wei, Wei; Pan, Wen-Jia; Lu, Long; Li, Qing-Tian; Ma, Jin-Biao; Zhang, Wan-Ke; Ma, Biao; Chen, Shou-Yi; Zhang, Jin-Song

    2018-02-09

    Alfin-like (AL) is a small plant-specific gene family with prominent roles in root growth and abiotic stress response. Here, we aimed to identify novel stress tolerance AL genes from the stress-tolerant species Atriplex hortensis. Totally, we isolated four AhAL genes, all encoding nuclear-localized proteins with cis-element-binding and transrepression activities. Constitutive expression of AhAL1 in Arabidopsis facilitated plants to survive under saline condition, while expressing anyone of the other three AhAL genes led to salt-hypersensitive response, indicating functional divergence of AhAL family. AhAL1 also conferred enhanced drought tolerance, as judged from enhanced survival, improved growth, decreased malonaldehyde (MDA) content and reduced water loss in AhAL1-expressing plants compared to WT. In addition, abscisic acid (ABA)-mediated stomatal closure and inhibition of seed germination and primary root elongation were enhanced in AhAL1-transgenic plants. Further analysis demonstrated that AhAL1 could bind to promoter regions of GRF7, DREB1C and several group-A PP2C genes and repress their expression. Correspondingly, the expression levels of positive stress regulator genes DREB1A, DREB2A and three ABFs were all increased in AhAL1-expressing plants. Based on these results, AhAL1 was identified as a novel candidate gene for improving abiotic stress tolerance of crop plants.

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

    Science.gov (United States)

    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. Proteogenomic analysis reveals alternative splicing and translation as part of the abscisic acid response in Arabidopsis seedlings.

    Science.gov (United States)

    Zhu, Fu-Yuan; Chen, Mo-Xian; Ye, Neng-Hui; Shi, Lu; Ma, Kai-Long; Yang, Jing-Fang; Cao, Yun-Ying; Zhang, Youjun; Yoshida, Takuya; Fernie, Alisdair R; Fan, Guang-Yi; Wen, Bo; Zhou, Ruo; Liu, Tie-Yuan; Fan, Tao; Gao, Bei; Zhang, Di; Hao, Ge-Fei; Xiao, Shi; Liu, Ying-Gao; Zhang, Jianhua

    2017-08-01

    In eukaryotes, mechanisms such as alternative splicing (AS) and alternative translation initiation (ATI) contribute to organismal protein diversity. Specifically, splicing factors play crucial roles in responses to environment and development cues; however, the underlying mechanisms are not well investigated in plants. Here, we report the parallel employment of short-read RNA sequencing, single molecule long-read sequencing and proteomic identification to unravel AS isoforms and previously unannotated proteins in response to abscisic acid (ABA) treatment. Combining the data from the two sequencing methods, approximately 83.4% of intron-containing genes were alternatively spliced. Two AS types, which are referred to as alternative first exon (AFE) and alternative last exon (ALE), were more abundant than intron retention (IR); however, by contrast to AS events detected under normal conditions, differentially expressed AS isoforms were more likely to be translated. ABA extensively affects the AS pattern, indicated by the increasing number of non-conventional splicing sites. This work also identified thousands of unannotated peptides and proteins by ATI based on mass spectrometry and a virtual peptide library deduced from both strands of coding regions within the Arabidopsis genome. The results enhance our understanding of AS and alternative translation mechanisms under normal conditions, and in response to ABA treatment. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  18. Abscisic acid alleviates iron deficiency by promoting root iron reutilization and transport from root to shoot in Arabidopsis.

    Science.gov (United States)

    Lei, Gui Jie; Zhu, Xiao Fang; Wang, Zhi Wei; Dong, Fang; Dong, Ning Yu; Zheng, Shao Jian

    2014-04-01

    Abscisic acid (ABA) has been demonstrated to be involved in iron (Fe) homeostasis, but the underlying mechanism is largely unknown. Here, we found that Fe deficiency induced ABA accumulation rapidly (within 6 h) in the roots of Arabidopsis. Exogenous ABA at 0.5 μM decreased the amount of root apoplastic Fe bound to pectin and hemicellulose, and increased the shoot Fe content significantly, thus alleviating Fe deficiency-induced chlorosis. Exogenous ABA promoted the secretion of phenolics to release apoplastic Fe and up-regulated the expression of AtNRAMP3 to enhance reutilization of Fe stored in the vacuoles, leading to a higher level of soluble Fe and lower ferric-chelate reductase (FCR) activity in roots. Treatment with ABA also led to increased Fe concentrations in the xylem sap, partially because of the up-regulation of AtFRD3, AtYSL2 and AtNAS1, genes related to long-distance transport of Fe. Exogenous ABA could not alleviate the chlorosis of abi5 mutant resulting from the significantly low expression of AtYSL2 and low transport of Fe from root to shoot. Taken together, our data support the conclusion that ABA is involved in the reutilization and transport of Fe from root to shoot under Fe deficiency conditions in Arabidopsis. © 2013 John Wiley & Sons Ltd.

  19. Abscisic Acid Signaling and Abiotic Stress Tolerance in Plants: A Review on Current Knowledge and Future Prospects.

    Science.gov (United States)

    Vishwakarma, Kanchan; Upadhyay, Neha; Kumar, Nitin; Yadav, Gaurav; Singh, Jaspreet; Mishra, Rohit K; Kumar, Vivek; Verma, Rishi; Upadhyay, R G; Pandey, Mayank; Sharma, Shivesh

    2017-01-01

    Abiotic stress is one of the severe stresses of environment that lowers the growth and yield of any crop even on irrigated land throughout the world. A major phytohormone abscisic acid (ABA) plays an essential part in acting toward varied range of stresses like heavy metal stress, drought, thermal or heat stress, high level of salinity, low temperature, and radiation stress. Its role is also elaborated in various developmental processes including seed germination, seed dormancy, and closure of stomata. ABA acts by modifying the expression level of gene and subsequent analysis of cis - and trans -acting regulatory elements of responsive promoters. It also interacts with the signaling molecules of processes involved in stress response and development of seeds. On the whole, the stress to a plant can be susceptible or tolerant by taking into account the coordinated activities of various stress-responsive genes. Numbers of transcription factor are involved in regulating the expression of ABA responsive genes by acting together with their respective cis -acting elements. Hence, for improvement in stress-tolerance capacity of plants, it is necessary to understand the mechanism behind it. On this ground, this article enlightens the importance and role of ABA signaling with regard to various stresses as well as regulation of ABA biosynthetic pathway along with the transcription factors for stress tolerance.

  20. The Interrelationship between Abscisic Acid and Reactive Oxygen Species Plays a Key Role in Barley Seed Dormancy and Germination.

    Science.gov (United States)

    Ishibashi, Yushi; Aoki, Nozomi; Kasa, Shinsuke; Sakamoto, Masatsugu; Kai, Kyohei; Tomokiyo, Reisa; Watabe, Gaku; Yuasa, Takashi; Iwaya-Inoue, Mari

    2017-01-01

    Seed dormancy is one of the adaptive responses in the plant life cycle and an important agronomic trait. Reactive oxygen species (ROS) release seed dormancy and promote seed germination in several cereal crops; however, the key regulatory mechanism of ROS-mediated seed dormancy and germination remains controversial. Here, we focused on the relationship between hydrogen peroxide (a ROS) and abscisic acid (ABA) in dormant and non-dormant barley seeds. The hydrogen peroxide (H 2 O 2 ) level produced in barley seed embryos after imbibition was higher in non-dormant seeds than in dormant seeds. H 2 O 2 regulated the ABA content in the embryos through ABA-8'-hydroxylase, an ABA catabolic enzyme. Moreover, compared with non-dormant seeds, in dormant seeds the activity of NADPH oxidase, which produces ROS, was lower, whereas the activity of catalase, which is a H 2 O 2 scavenging enzyme, was higher, as was the expression of HvCAT2 . Furthermore, precocious germination of isolated immature embryos was suppressed by the transient introduction of HvCAT2 driven by the maize ( Zea mays ) ubiquitin promoter. HvCAT2 expression was regulated through an ABA-responsive transcription factor (HvABI5) induced by ABA. These results suggest that the changing of balance between ABA and ROS is active in barley seed embryos after imbibition and regulates barley seed dormancy and germination.

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

    International Nuclear Information System (INIS)

    Rakitina, T.Ya.; Vlasov, P.V.; Jalilova, F.Kh.; Kefeli, V.I.

    1994-01-01

    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

  2. Overexpression of Pyrabactin Resistance-Like Abscisic Acid Receptors Enhances Drought, Osmotic, and Cold Tolerance in Transgenic Poplars

    Directory of Open Access Journals (Sweden)

    Jingling Yu

    2017-10-01

    Full Text Available Abscisic acid (ABA has been known participate in a wider range of adaptive responses to diverse environmental abiotic stresses such as drought, osmosis, and low temperatures. ABA signaling is initiated by its receptors PYR/PYL/RCARs, a type of soluble proteins with a conserved START domain which can bind ABA and trigger the downstream pathway. Previously, we discovered that poplar (Populus trichocarpa genome encodes 14 PYR/PYL/RCAR orthologs (PtPYRLs, and two of them, PtPYRL1 and PtPYRL5 have been functionally characterized to positively regulate drought tolerance. However, the physiological function of these ABA receptors in poplar remains uncharacterized. Here, we generated transgenic poplar plants overexpressing PtPYRL1 and PtPYRL5 and found that they exhibited more vigorous growth and produced greater biomass when exposed to drought stress. The improved drought tolerance was positively correlated with the key physiological responses dictated by the ABA signaling pathway, including increase in stomatal closure and decrease in leaf water loss. Further analyses revealed that overexpression lines showed improved capacity in scavenging reactive oxygen species and enhanced the activation of antioxidant enzymes under drought stress. Moreover, overexpression of PtPYRL1 or PtPYRL5 significantly increased the poplar resistance to osmotic and cold stresses. In summary, our results suggest that constitutive expression of PtPYRL1 and PtPYRL5 significantly enhances the resistance to drought, osmotic and cold stresses by positively regulating ABA signaling in poplar.

  3. Abscisic acid deficiency causes changes in cuticle permeability and pectin composition that influence tomato resistance to Botrytis cinerea.

    Science.gov (United States)

    Curvers, Katrien; Seifi, Hamed; Mouille, Grégory; de Rycke, Riet; Asselbergh, Bob; Van Hecke, Annelies; Vanderschaeghe, Dieter; Höfte, Herman; Callewaert, Nico; Van Breusegem, Frank; Höfte, Monica

    2010-10-01

    A mutant of tomato (Solanum lycopersicum) with reduced abscisic acid (ABA) production (sitiens) exhibits increased resistance to the necrotrophic fungus Botrytis cinerea. This resistance is correlated with a rapid and strong hydrogen peroxide-driven cell wall fortification response in epidermis cells that is absent in tomato with normal ABA production. Moreover, basal expression of defense genes is higher in the mutant compared with the wild-type tomato. Given the importance of this fast response in sitiens resistance, we investigated cell wall and cuticle properties of the mutant at the chemical, histological, and ultrastructural levels. We demonstrate that ABA deficiency in the mutant leads to increased cuticle permeability, which is positively correlated with disease resistance. Furthermore, perturbation of ABA levels affects pectin composition. sitiens plants have a relatively higher degree of pectin methylesterification and release different oligosaccharides upon inoculation with B. cinerea. These results show that endogenous plant ABA levels affect the composition of the tomato cuticle and cell wall and demonstrate the importance of cuticle and cell wall chemistry in shaping the outcome of this plant-fungus interaction.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Ethylene responses in rice roots and coleoptiles are differentially regulated by a carotenoid isomerase-mediated abscisic acid pathway.

    Science.gov (United States)

    Yin, Cui-Cui; Ma, Biao; Collinge, Derek Phillip; Pogson, Barry James; He, Si-Jie; Xiong, Qing; Duan, Kai-Xuan; Chen, Hui; Yang, Chao; Lu, Xiang; Wang, Yi-Qin; Zhang, Wan-Ke; Chu, Cheng-Cai; Sun, Xiao-Hong; Fang, Shuang; Chu, Jin-Fang; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2015-04-01

    Ethylene and abscisic acid (ABA) act synergistically or antagonistically to regulate plant growth and development. ABA is derived from the carotenoid biosynthesis pathway. Here, we analyzed the interplay among ethylene, carotenoid biogenesis, and ABA in rice (Oryza sativa) using the rice ethylene response mutant mhz5, which displays a reduced ethylene response in roots but an enhanced ethylene response in coleoptiles. We found that MHZ5 encodes a carotenoid isomerase and that the mutation in mhz5 blocks carotenoid biosynthesis, reduces ABA accumulation, and promotes ethylene production in etiolated seedlings. ABA can largely rescue the ethylene response of the mhz5 mutant. Ethylene induces MHZ5 expression, the production of neoxanthin, an ABA biosynthesis precursor, and ABA accumulation in roots. MHZ5 overexpression results in enhanced ethylene sensitivity in roots and reduced ethylene sensitivity in coleoptiles. Mutation or overexpression of MHZ5 also alters the expression of ethylene-responsive genes. Genetic studies revealed that the MHZ5-mediated ABA pathway acts downstream of ethylene signaling to inhibit root growth. The MHZ5-mediated ABA pathway likely acts upstream but negatively regulates ethylene signaling to control coleoptile growth. Our study reveals novel interactions among ethylene, carotenogenesis, and ABA and provides insight into improvements in agronomic traits and adaptive growth through the manipulation of these pathways in rice. © 2015 American Society of Plant Biologists. All rights reserved.

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

    Science.gov (United States)

    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.

  7. The role of the atypical kinases ABC1K7 and ABC1K8 in abscisic acid responses

    Directory of Open Access Journals (Sweden)

    Anna eManara

    2016-03-01

    Full Text Available The ABC1K family of atypical kinases (activity of bc1 complex kinase is represented in bacteria, archaea and eukaryotes. In plants they regulate diverse physiological processes in the chloroplasts and mitochondria, but their precise functions are poorly defined. ABC1K7 and ABC1K8 are probably involved in oxidative stress responses, isoprenyl lipid synthesis and distribution of iron within chloroplasts. Because reactive oxygen species take part in abscisic acid (ABA-mediated processes, we investigated the functions of ABC1K7 and ABC1K8 during germination, stomatal movement and leaf senescence. Both genes were upregulated by ABA treatment and some ABA-responsive physiological processes were affected in abc1k7 and abc1k8 mutants. Germination was more severely affected by ABA, osmotic stress and salt stress in the single and double mutants; the stomatal aperture was smaller in the mutants under standard growth conditions and was not further reduced by exogenous ABA application; ABA-induced senescence symptoms were more severe in the leaves of the single and double mutants compared to wild type leaves. Taken together, our results suggest that ABC1K7 and ABC1K8 might be involved in the cross-talk between ABA and ROS signaling.

  8. Dehydration stress-induced oscillations in LEA protein transcripts involves abscisic acid in the moss, Physcomitrella patens.

    Science.gov (United States)

    Shinde, Suhas; Nurul Islam, M; Ng, Carl K-Y

    2012-07-01

    • Physcomitrella patens is a bryophyte belonging to early diverging lineages of land plants following colonization of land in the Ordovician period. Mosses are typically found in refugial habitats and can experience rapidly fluctuating environmental conditions. The acquisition of dehydration tolerance by bryophytes is of fundamental importance as they lack water-conducting tissues and are generally one cell layer thick. • Here, we show that dehydration induced oscillations in the steady-state transcript abundances of two group 3 late embryogenesis abundant (LEA) protein genes in P. patens protonemata, and that the amplitudes of these oscillations are reflective of the severity of dehydration stress. • Dehydration stress also induced elevations in the concentrations of abscisic acid (ABA), and ABA alone can also induce dosage-dependent oscillatory increases in the steady-state abundance of LEA protein transcripts. Additionally, removal of ABA resulted in rapid attenuation of these oscillatory increases. • Our data demonstrate that dehydration stress-regulated expression of LEA protein genes is temporally dynamic and highlight the importance of oscillations as a robust mechanism for optimal responses. Our results suggest that dehydration stress-induced oscillations in the steady-state abundance of LEA protein transcripts may constitute an important cellular strategy for adaptation to life in a constantly changing environment. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

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

    Science.gov (United States)

    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. © 2014 The Authors New Phytologist © 2014 New Phytologist Trust.

  10. Microarray analysis of transcriptional responses to abscisic acid and osmotic, salt, and drought stress in the moss, Physcomitrella patens.

    Science.gov (United States)

    Cuming, Andrew C; Cho, Sung Hyun; Kamisugi, Yasuko; Graham, Helen; Quatrano, Ralph S

    2007-01-01

    Dehydration tolerance was an adaptive trait necessary for the colonization of land by plants, and remains widespread among bryophytes: the nearest extant relatives of the first land plants. A genome-wide analysis was undertaken of water-stress responses in the model moss Physcomitrella patens to identify stress-responsive genes. An oligonucleotide microarray was used for transcriptomic analysis of Physcomitrella treated with abscisic acid (ABA), or subjected to osmotic, salt and drought stress. Bioinformatic analysis of the Physcomitrella genome identified the responsive genes, and a number of putative stress-related cis-regulatory elements. In protonemal tissue, 130 genes were induced by dehydration, 56 genes by ABA, but only 10 and eight genes, respectively, by osmotic and salt stress. Fifty-one genes were induced by more than one treatment. Seventy-six genes, principally encoding chloroplast proteins, were drought down-regulated. Many ABA- and drought-responsive genes are homologues of angiosperm genes expressed during drought stress and seed development. These ABA- and drought-responsive genes include those encoding a number of late embryogenesis abundant (LEA) proteins, a 'DREB' transcription factor and a Snf-related kinase homologous with the Arabidopsis ABA signal transduction component 'OPEN STOMATA 1'. Evolutionary capture of conserved stress-regulatory transcription factors by the seed developmental pathway probably accounts for the seed-specificity of desiccation tolerance among angiosperms.

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

    Science.gov (United States)

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

    2015-05-06

    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.

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

    Science.gov (United States)

    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.

  13. LANCL2 is necessary for abscisic acid binding and signaling in human granulocytes and in rat insulinoma cells.

    Science.gov (United States)

    Sturla, Laura; Fresia, Chiara; Guida, Lucrezia; Bruzzone, Santina; Scarfì, Sonia; Usai, Cesare; Fruscione, Floriana; Magnone, Mirko; Millo, Enrico; Basile, Giovanna; Grozio, Alessia; Jacchetti, Emanuela; Allegretti, Marcello; De Flora, Antonio; Zocchi, Elena

    2009-10-09

    Abscisic acid (ABA) is a plant hormone regulating fundamental physiological functions in plants, such as response to abiotic stress. Recently, ABA was shown to be produced and released by human granulocytes, by insulin-producing rat insulinoma cells, and by human and murine pancreatic beta cells. ABA autocrinally stimulates the functional activities specific for each cell type through a receptor-operated signal transduction pathway, sequentially involving a pertussis toxin-sensitive receptor/G-protein complex, cAMP, CD38-produced cADP-ribose and intracellular calcium. Here we show that the lanthionine synthetase C-like protein LANCL2 is required for ABA binding on the membrane of human granulocytes and that LANCL2 is necessary for transduction of the ABA signal into the cell-specific functional responses in granulocytes and in rat insulinoma cells. Co-expression of LANCL2 and CD38 in the human HeLa cell line reproduces the ABA-signaling pathway. Results obtained with granulocytes and CD38(+)/LANCL2(+) HeLa transfected with a chimeric G-protein (G alpha(q/i)) suggest that the pertussis toxin-sensitive G-protein coupled to LANCL2 is a G(i). Identification of LANCL2 as a critical component of the ABA-sensing protein complex will enable the screening of synthetic ABA antagonists as prospective new anti-inflammatory and anti-diabetic agents.

  14. Microgram amounts of abscisic acid in fruit extracts improve glucose tolerance and reduce insulinemia in rats and in humans.

    Science.gov (United States)

    Magnone, Mirko; Ameri, Pietro; Salis, Annalisa; Andraghetti, Gabriella; Emionite, Laura; Murialdo, Giovanni; De Flora, Antonio; Zocchi, Elena

    2015-12-01

    2-Cis,4-trans-abscisic acid (ABA) is a plant hormone that is present also in animals. Several lines of evidence suggest that ABA contributes to the regulation of glycemia in mammals: nanomolar ABA stimulates insulin release from β-pancreatic cells and glucose transporter-4-mediated glucose uptake by myoblasts and adipocytes in vitro; plasma ABA increases in normal human subjects, but not in diabetic patients, after a glucose load for an oral glucose tolerance test (OGTT). The presence of ABA in fruits prompted an exploration of the bioavailability of dietary ABA and the effect of ABA-rich fruit extracts on glucose tolerance. Rats underwent an OGTT, with or without 1 µg/kg ABA, either synthetic or present in a fruit extract. Human volunteers underwent an OGTT or a standard breakfast and lunch, with or without a fruit extract, yielding an ABA dose of 0.85 or 0.5 µg/kg, respectively. Plasma glucose, insulin, and ABA were measured at different time points. Oral ABA at 0.5-1 µg/kg significantly lowered glycemia and insulinemia in rats and in humans. Thus, the glycemia-lowering effect of low-dose ABA in vivo does not depend on an increased insulin release. Low-dose ABA intake may be proposed as an aid to improving glucose tolerance in patients with diabetes who are deficient in or resistant to insulin. © FASEB.

  15. The plant hormone abscisic acid stimulates the proliferation of human hemopoietic progenitors through the second messenger cyclic ADP-ribose.

    Science.gov (United States)

    Scarfì, Sonia; Fresia, Chiara; Ferraris, Chiara; Bruzzone, Santina; Fruscione, Floriana; Usai, Cesare; Benvenuto, Federica; Magnone, Mirko; Podestà, Marina; Sturla, Laura; Guida, Lucrezia; Albanesi, Ennio; Damonte, Gianluca; Salis, Annalisa; De Flora, Antonio; Zocchi, Elena

    2009-10-01

    Abscisic acid (ABA) is a hormone involved in pivotal physiological functions in higher plants, such as response to abiotic stress and control of seed dormancy and germination. Recently, ABA was demonstrated to be autocrinally produced by human granulocytes, beta pancreatic cells, and mesenchymal stem cells (MSC) and to stimulate cell-specific functions through a signaling pathway involving the second messenger cyclic ADP-ribose (cADPR). Here we show that ABA expands human uncommitted hemopoietic progenitors (HP) in vitro, through a cADPR-mediated increase of the intracellular calcium concentration ([Ca(2+)](i)). Incubation of CD34(+) cells with micromolar ABA also induces transcriptional effects, which include NF-kappaB nuclear translocation and transcription of genes encoding for several cytokines. Human MSC stimulated with a lymphocyte-conditioned medium produce and release ABA at concentrations sufficient to exert growth-stimulatory effects on co-cultured CD34(+) cells, as demonstrated by the inhibition of colony growth in the presence of an anti-ABA monoclonal antibody. These results provide a remarkable example of conservation of a stress hormone and of its second messenger from plants to humans and identify ABA as a new hemopoietic growth factor involved in the cross-talk between HP and MSC.

  16. Abscisic acid is an endogenous stimulator of insulin release from human pancreatic islets with cyclic ADP ribose as second messenger.

    Science.gov (United States)

    Bruzzone, Santina; Bodrato, Nicoletta; Usai, Cesare; Guida, Lucrezia; Moreschi, Iliana; Nano, Rita; Antonioli, Barbara; Fruscione, Floriana; Magnone, Mirko; Scarfì, Sonia; De Flora, Antonio; Zocchi, Elena

    2008-11-21

    Abscisic acid (ABA) is a plant stress hormone recently identified as an endogenous pro-inflammatory cytokine in human granulocytes. Because paracrine signaling between pancreatic beta cells and inflammatory cells is increasingly recognized as a pathogenetic mechanism in the metabolic syndrome and type II diabetes, we investigated the effect of ABA on insulin secretion. Nanomolar ABA increases glucose-stimulated insulin secretion from RIN-m and INS-1 cells and from murine and human pancreatic islets. The signaling cascade triggered by ABA in insulin-releasing cells sequentially involves a pertussis toxin-sensitive G protein, cAMP overproduction, protein kinase A-mediated activation of the ADP-ribosyl cyclase CD38, and cyclic ADP-ribose overproduction. ABA is rapidly produced and released from human islets, RIN-m, and INS-1 cells stimulated with high glucose concentrations. In conclusion, ABA is an endogenous stimulator of insulin secretion in human and murine pancreatic beta cells. Autocrine release of ABA by glucose-stimulated pancreatic beta cells, and the paracrine production of the hormone by activated granulocytes and monocytes suggest that ABA may be involved in the physiology of insulin release as well as in its dysregulation under conditions of inflammation.

  17. Abscisic acid released by human monocytes activates monocytes and vascular smooth muscle cell responses involved in atherogenesis.

    Science.gov (United States)

    Magnone, Mirko; Bruzzone, Santina; Guida, Lucrezia; Damonte, Gianluca; Millo, Enrico; Scarfì, Sonia; Usai, Cesare; Sturla, Laura; Palombo, Domenico; De Flora, Antonio; Zocchi, Elena

    2009-06-26

    Abscisic acid (ABA) is a phytohormone recently identified as a new endogenous pro-inflammatory hormone in human granulocytes. Here we report the functional activation of human monocytes and vascular smooth muscle cells by ABA. Incubation of monocytes with ABA evokes an intracellular Ca2+ rise through the second messenger cyclic ADP-ribose, leading to NF-kappaB activation and consequent increase of cyclooxygenase-2 expression and prostaglandin E2 production and enhanced release of MCP-1 (monocyte chemoattractant protein-1) and of metalloprotease-9, all events reportedly involved in atherogenesis. Moreover, monocytes release ABA when exposed to thrombin-activated platelets, a condition occurring at the injured vascular endothelium; monocyte-derived ABA behaves as an autocrine and paracrine pro-inflammatory hormone-stimulating monocyte migration and MCP-1 release, as well as vascular smooth muscle cells migration and proliferation. These results, and the presence of ABA in human arterial plaques at a 10-fold higher concentration compared with normal arterial tissue, identify ABA as a new signal molecule involved in the development of atherosclerosis and suggest a possible new target for anti-atherosclerotic therapy.

  18. Abscisic Acid Released by Human Monocytes Activates Monocytes and Vascular Smooth Muscle Cell Responses Involved in Atherogenesis*

    Science.gov (United States)

    Magnone, Mirko; Bruzzone, Santina; Guida, Lucrezia; Damonte, Gianluca; Millo, Enrico; Scarfì, Sonia; Usai, Cesare; Sturla, Laura; Palombo, Domenico; De Flora, Antonio; Zocchi, Elena

    2009-01-01

    Abscisic acid (ABA) is a phytohormone recently identified as a new endogenous pro-inflammatory hormone in human granulocytes. Here we report the functional activation of human monocytes and vascular smooth muscle cells by ABA. Incubation of monocytes with ABA evokes an intracellular Ca2+ rise through the second messenger cyclic ADP-ribose, leading to NF-κB activation and consequent increase of cyclooxygenase-2 expression and prostaglandin E2 production and enhanced release of MCP-1 (monocyte chemoattractant protein-1) and of metalloprotease-9, all events reportedly involved in atherogenesis. Moreover, monocytes release ABA when exposed to thrombin-activated platelets, a condition occurring at the injured vascular endothelium; monocyte-derived ABA behaves as an autocrine and paracrine pro-inflammatory hormone-stimulating monocyte migration and MCP-1 release, as well as vascular smooth muscle cells migration and proliferation. These results, and the presence of ABA in human arterial plaques at a 10-fold higher concentration compared with normal arterial tissue, identify ABA as a new signal molecule involved in the development of atherosclerosis and suggest a possible new target for anti-atherosclerotic therapy. PMID:19332545

  19. The plant hormone abscisic acid increases in human plasma after hyperglycemia and stimulates glucose consumption by adipocytes and myoblasts.

    Science.gov (United States)

    Bruzzone, Santina; Ameri, Pietro; Briatore, Lucia; Mannino, Elena; Basile, Giovanna; Andraghetti, Gabriella; Grozio, Alessia; Magnone, Mirko; Guida, Lucrezia; Scarfì, Sonia; Salis, Annalisa; Damonte, Gianluca; Sturla, Laura; Nencioni, Alessio; Fenoglio, Daniela; Fiory, Francesca; Miele, Claudia; Beguinot, Francesco; Ruvolo, Vittorio; Bormioli, Mariano; Colombo, Giuseppe; Maggi, Davide; Murialdo, Giovanni; Cordera, Renzo; De Flora, Antonio; Zocchi, Elena

    2012-03-01

    The plant hormone abscisic acid (ABA) is released from glucose-challenged human pancreatic β cells and stimulates insulin secretion. We investigated whether plasma ABA increased during oral and intravenous glucose tolerance tests (OGTTs and IVGTTs) in healthy human subjects. In all subjects undergoing OGTTs (n=8), plasma ABA increased over basal values (in a range from 2- to 9-fold). A positive correlation was found between the ABA area under the curve (AUC) and the glucose AUC. In 4 out of 6 IVGTTs, little or no increase of ABA levels was observed. In the remaining subjects, the ABA increase was similar to that recorded during OGTTs. GLP-1 stimulated ABA release from an insulinoma cell line and from human islets, by ∼10- and 2-fold in low and high glucose, respectively. Human adipose tissue also released ABA in response to high glucose. Nanomolar ABA stimulated glucose uptake, similarly to insulin, in rat L6 myoblasts and in murine 3T3-L1 cells differentiated to adipocytes, by increasing GLUT-4 translocation to the plasma membrane. Demonstration that a glucose load in humans is followed by a physiological rise of plasma ABA, which can enhance glucose uptake by adipose tissues and muscle cells, identifies ABA as a new mammalian hormone involved in glucose metabolism.

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

    KAUST Repository

    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.

  1. The Interrelationship between Abscisic Acid and Reactive Oxygen Species Plays a Key Role in Barley Seed Dormancy and Germination

    Science.gov (United States)

    Ishibashi, Yushi; Aoki, Nozomi; Kasa, Shinsuke; Sakamoto, Masatsugu; Kai, Kyohei; Tomokiyo, Reisa; Watabe, Gaku; Yuasa, Takashi; Iwaya-Inoue, Mari

    2017-01-01

    Seed dormancy is one of the adaptive responses in the plant life cycle and an important agronomic trait. Reactive oxygen species (ROS) release seed dormancy and promote seed germination in several cereal crops; however, the key regulatory mechanism of ROS-mediated seed dormancy and germination remains controversial. Here, we focused on the relationship between hydrogen peroxide (a ROS) and abscisic acid (ABA) in dormant and non-dormant barley seeds. The hydrogen peroxide (H2O2) level produced in barley seed embryos after imbibition was higher in non-dormant seeds than in dormant seeds. H2O2 regulated the ABA content in the embryos through ABA-8′-hydroxylase, an ABA catabolic enzyme. Moreover, compared with non-dormant seeds, in dormant seeds the activity of NADPH oxidase, which produces ROS, was lower, whereas the activity of catalase, which is a H2O2 scavenging enzyme, was higher, as was the expression of HvCAT2. Furthermore, precocious germination of isolated immature embryos was suppressed by the transient introduction of HvCAT2 driven by the maize (Zea mays) ubiquitin promoter. HvCAT2 expression was regulated through an ABA-responsive transcription factor (HvABI5) induced by ABA. These results suggest that the changing of balance between ABA and ROS is active in barley seed embryos after imbibition and regulates barley seed dormancy and germination. PMID:28377774

  2. Gibberellins and Seed Development in Maize. I. Evidence That Gibberellin/Abscisic Acid Balance Governs Germination versus Maturation Pathways1

    Science.gov (United States)

    White, Constance N.; Proebsting, William M.; Hedden, Peter; Rivin, Carol J.

    2000-01-01

    Abscisic acid (ABA) is required for the regulation of seed maturation in maize (Zea mays L.). Mutants blocked in ABA synthesis (such as viviparous-5) do not mature to quiescent, desiccation-tolerant seeds, but germinate on the ear midway through kernel development. Because gibberellins (GA) and ABA act antagonistically in many aspects of plant development, we hypothesized that ABA antagonizes a positive GA signal for precocious germination in maize. In these experiments, we show that a GA deficiency early in seed development, induced genetically or via biosynthesis inhibitors, suppresses vivipary in ABA-deficient developing kernels. The resulting seeds have both desiccation tolerance and storage longevity. Temporal analysis of GA accumulation in wild-type kernels revealed the accumulation of bioactive GA1 and GA3 prior to the peak in ABA content. We speculate that these GAs stimulate a developmental program leading to vivipary in the absence of normal amounts of ABA, and that a reduction of GA content re-establishes an ABA/GA ratio appropriate for suppression of germination and induction of maturation. In contrast, the induction of a GA deficiency did not suppress vivipary in viviparous-1 mutant kernels, suggesting that VP1 acts downstream of both GA and ABA in programming seed development. PMID:10759503

  3. Hydrogen peroxide mediates abscisic acid-induced HSP70 accumulation and heat tolerance in grafted cucumber plants.

    Science.gov (United States)

    Li, Hao; Liu, Shan-Shan; Yi, Chang-Yu; Wang, Feng; Zhou, Jie; Xia, Xiao-Jian; Shi, Kai; Zhou, Yan-Hong; Yu, Jing-Quan

    2014-12-01

    Root-shoot communications play important roles in plant stress responses. Here, we examined the roles of root-sourced signals in the shoot response to heat in cucumber plants. Cucumber plants grafted onto their own roots and luffa roots were exposed to aerial and root-zone heat to examine their tolerance by assessing the levels of oxidative stress, PSII photoinhibition, accumulation of abscisic acid (ABA), H2 O2 and heat shock protein (HSP) 70 using immunoblotting, chlorophyll fluorescence, immunoassay, CeCl3 staining and Western blotting, respectively. Grafting onto the luffa rootstock enhanced the shoot tolerance to the heat. This enhanced tolerance was associated with increased accumulation of ABA and apoplastic H2 O2 , RBOH transcripts and HSP70 expression and a decrease in oxidative stress in the shoots. The increases in the ABA and H2 O2 concentrations in the shoots were attributed to an increase in ABA transport from roots and an increase in ABA biosynthesis in the shoots when the root-zone and shoots were heat stressed, respectively. Inhibition of H2 O2 accumulation compromised luffa rootstock-induced HSP70 expression and heat tolerance. These results suggest that, under heat stress, ABA triggers the expression of HSP70 in an apoplastic H2 O2 -dependent manner, implicating the role of an ABA-dependent H2 O2 -driven mechanism in a systemic response involving root-shoot communication. © 2014 John Wiley & Sons Ltd.

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

    KAUST Repository

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Effect of Exogenous Abscisic Acid and Methyl Jasmonate on Anthocyanin Composition, Fatty Acids, and Volatile Compounds of Cabernet Sauvignon (Vitis vinifera L. Grape Berries

    Directory of Open Access Journals (Sweden)

    Yan-Lun Ju

    2016-10-01

    Full Text Available The anthocyanin composition, fatty acids, and volatile aromas are important for Cabernet Sauvignon grape quality. This study evaluated the effect of exogenous abscisic acid (ABA and methyl jasmonate (MeJA on the anthocyanin composition, fatty acids, lipoxygenase activity, and the volatile compounds of Cabernet Sauvignon grape berries. Exogenous ABA and MeJA improved the content of total anthocyanins (TAC and individual anthocyanins. Lipoxygenase (LOX activity also increased after treatment. Furthermore, 16 fatty acids were detected. The linoleic acid concentration gradually increased with ABA concentration. The fatty acid content decreased with increasing MeJA concentration and then increased again, with the exception of linoleic acid. After exogenous ABA and MeJA treatment, the C6 aroma content increased significantly. Interestingly, the exogenous ABA and MeJA treatments improved mainly the content of 1-hexanol, hexanal, and 2-heptanol. These results provide insight into the effect of plant hormones on wine grapes, which is useful for grape quality improvement.

  8. Effects of abscisic acid on ethylene biosynthesis and perception in Hibiscus rosa-sinensis L. flower development

    Science.gov (United States)

    Trivellini, Alice; Ferrante, Antonio; Vernieri, Paolo; Serra, Giovanni

    2011-01-01

    The effect of the complex relationship between ethylene and abscisic acid (ABA) on flower development and senescence in Hibiscus rosa-sinensis L. was investigated. Ethylene biosynthetic (HrsACS and HrsACO) and receptor (HrsETR and HrsERS) genes were isolated and their expression evaluated in three different floral tissues (petals, style–stigma plus stamens, and ovaries) of detached buds and open flowers. This was achieved through treatment with 0.1 mM 1-aminocyclopropane-1-carboxylic acid (ACC) solution, 500 nl l−1 methylcyclopropene (1-MCP), and 0.1 mM ABA solution. Treatment with ACC and 1-MCP confirmed that flower senescence in hibiscus is ethylene dependent, and treatment with exogenous ABA suggested that ABA may play a role in this process. The 1-MCP impeded petal in-rolling and decreased ABA content in detached open flowers after 9 h. This was preceded by an earlier and sequential increase in ABA content in 1-MCP-treated petals and style–stigma plus stamens between 1 h and 6 h. ACC treatment markedly accelerated flower senescence and increased ethylene production after 6 h and 9 h, particularly in style–stigma plus stamens. Ethylene evolution was positively correlated in these floral tissues with the induction of the gene expression of ethylene biosynthetic and receptor genes. Finally, ABA negatively affected the ethylene biosynthetic pathway and tissue sensitivity in all flower tissues. Transcript abundance of HrsACS, HrsACO, HrsETR, and HrsERS was reduced by exogenous ABA treatment. This research underlines the regulatory effect of ABA on the ethylene biosynthetic and perception machinery at a physiological and molecular level when inhibitors or promoters of senescence are exogenously applied. PMID:21841180

  9. Abscisic acid enhances glucose disposal and induces brown fat activity in adipocytes in vitro and in vivo.

    Science.gov (United States)

    Sturla, Laura; Mannino, Elena; Scarfì, Sonia; Bruzzone, Santina; Magnone, Mirko; Sociali, Giovanna; Booz, Valeria; Guida, Lucrezia; Vigliarolo, Tiziana; Fresia, Chiara; Emionite, Laura; Buschiazzo, Ambra; Marini, Cecilia; Sambuceti, Gianmario; De Flora, Antonio; Zocchi, Elena

    2017-02-01

    Abscisic acid (ABA) is a plant hormone also present in animals, where it is involved in the regulation of innate immune cell function and of glucose disposal, through its receptor LANCL2. ABA stimulates glucose uptake by myocytes and pre-adipocytes in vitro and oral ABA improves glycemic control in rats and in healthy subjects. Here we investigated the role of the ABA/LANCL2 system in the regulation of glucose uptake and metabolism in adipocytes. Silencing of LANCL2 abrogated both the ABA- and insulin-induced increase of glucose transporter-4 expression and of glucose uptake in differentiated 3T3-L1 murine adipocytes; conversely, overexpression of LANCL2 enhanced basal, ABA- and insulin-stimulated glucose uptake. As compared with insulin, ABA treatment of adipocytes induced lower triglyceride accumulation, CO 2 production and glucose-derived fatty acid synthesis. ABA per se did not induce pre-adipocyte differentiation in vitro, but stimulated adipocyte remodeling in terminally differentiated cells, with a reduction in cell size, increased mitochondrial content, enhanced O 2 consumption, increased transcription of adiponectin and of brown adipose tissue (BAT) genes. A single dose of oral ABA (1μg/kg body weight) increased BAT glucose uptake 2-fold in treated rats compared with untreated controls. One-month-long ABA treatment at the same daily dose significantly upregulated expression of BAT markers in the WAT and in WAT-derived preadipocytes from treated mice compared with untreated controls. These results indicate a hitherto unknown role of LANCL2 in adipocyte sensitivity to insulin-stimulated glucose uptake and suggest a role for ABA in the induction and maintenance of BAT activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Abscisic acid metabolism and anthocyanin synthesis in grape skin are affected by light emitting diode (LED) irradiation at night.

    Science.gov (United States)

    Kondo, Satoru; Tomiyama, Hiroyuki; Rodyoung, Abhichartbut; Okawa, Katsuya; Ohara, Hitoshi; Sugaya, Sumiko; Terahara, Norihiko; Hirai, Nobuhiro

    2014-06-15

    The effects of blue and red light irradiation at night on abscisic acid (ABA) metabolism and anthocyanin synthesis were examined in grape berries. The expressions of VlMYBA1-2, VlMYBA2, UDP-glucose-flavonoid 3-O-glucosyltransferase (VvUFGT), 9-cis-epoxycarotenoid dioxygenase (VvNCED1), and ABA 8'-hydroxylase (VvCYP707A1) were also investigated. Endogenous ABA, its metabolite phaseic acid (PA), and the expressions of VvNCED1 and VvCYP707A1 were highest in red light-emitting diode (LED)-treated skin. In contrast, anthocyanin concentrations were highest in blue LED-treated skin, followed by red LED treatment. However, the expressions of VlMYBA1-2, VlMYBA2, and VvUFGT did not necessarily coincide with anthocyanin concentrations. The quality of coloring may depend on the amount of malvidin-based anthocyanin, which increased toward harvest in blue and red LED-treated skin, unlike in untreated controls. An increase in sugars was also observed in blue and red LED-treated skin. These results suggest that blue LED irradiation at night may be effective in increasing anthocyanin and sugar concentrations in grape berries. However, there is evidence that another factor may influence anthocyanin concentrations in grape berry skin significantly more than endogenous ABA: ABA concentrations were highest in red LED-treated skin, which had lower anthocyanin concentrations than blue LED-treated skin. Copyright © 2014 Elsevier GmbH. All rights reserved.

  11. Development of a rapid LC-DAD/FLD method for the simultaneous determination of auxins and abscisic acid in plant extracts.

    Science.gov (United States)

    Bosco, Renato; Caser, Matteo; Vanara, Francesca; Scariot, Valentina

    2013-11-20

    Plant hormones play a crucial role in controlling plant growth and development. These groups of naturally occurring substances trigger physiological processes at very low concentrations, which mandate sensitive techniques for their quantitation. This paper describes a method to quantify endogenous (±)-2-cis-4-trans-abscisic acid, indole-3-acetic acid, indole-3-propionic acid, and indole-3-butyric acid. The method combines high-performance liquid chromatography (HPLC) with diode array and fluorescence detection in a single run. Hybrid tea rose 'Monferrato' matrices (leaves, petals, roots, seeds, androecium, gynoecium, and pollen) were used as references. Rose samples were separated and suspended in extracting methanol, after which (±)-2-cis-4-trans-abscisic acid and auxins were extracted by solvent extraction. Sample solutions were added first to cation solid phase extraction (SPE) cartridges and the eluates to anion SPE cartridges. The acidic hormones were bound to the last column and eluted with 5% phosphoric acid in methanol. Experimental results showed that this approach can be successfully applied to real samples and that sample preparation and total time for routine analysis can be greatly reduced.

  12. Overexpression of OsWRKY72 gene interferes in the abscisic acid ...

    Indian Academy of Sciences (India)

    Prakash

    WRKY75 transcription factor is a modulator of phosphate acquisition and root development in Arabidopsis; Plant Physiol. 143 1789–1801. Du L Q and Chen Z X 2000 Identification of genes encoding receptor-like protein kinases as possible targets of pathogen- and salicylic acid-induced WRKY DNA-binding proteins in.

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

    International Nuclear Information System (INIS)

    Wilen, R.W.; Mandel, R.M.; Pharis, R.P.; Moloney, M.M.; Holbrook, L.A.

    1990-01-01

    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 [ 2 H 6 ]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

  14. Overexpression of sweet sorghum cryptochrome 1a confers hypersensitivity to blue light, abscisic acid and salinity in Arabidopsis.

    Science.gov (United States)

    Zhou, Tingting; Meng, Lingyang; Ma, Yue; Liu, Qing; Zhang, Yunyun; Yang, Zhenming; Yang, Deguang; Bian, Mingdi

    2018-02-01

    This work provides the bioinformatics, expression pattern and functional analyses of cryptochrome 1a from sweet sorghum (SbCRY1a), together with an exploration of the signaling mechanism mediated by SbCRY1a. Sweet sorghum [Sorghum bicolor (L.) Moench] is considered to be an ideal candidate for biofuel production due to its high efficiency of photosynthesis and the ability to maintain yield under harsh environmental conditions. Blue light receptor cryptochromes regulate multiple aspects of plant growth and development. Here, we reported the function and signal mechanism of sweet sorghum cryptochrome 1a (SbCRY1a) to explore its potential for genetic improvement of sweet sorghum varieties. SbCRY1a transcripts experienced almost 24 h diurnal cycling; however, its protein abundance showed no oscillation. Overexpression of SbCRY1a in Arabidopsis rescued the phenotype of cry1 mutant in a blue light-specific manner and regulated HY5 accumulation under blue light. SbCRY1a protein was present in both nucleus and cytoplasm. The photoexcited SbCRY1a interacted directly with a putative RING E3 ubiquitin ligase constitutive photomorphogenesis 1 (COP1) from sweet sorghum (SbCOP1) instead of SbSPA1 to suppress SbCOP1-SbHY5 interaction responding to blue light. These observations indicate that the function and signaling mechanism of cryptochromes are basically conservative between monocotyledons and dicotyledons. Moreover, SbCRY1a-overexpressed transgenic Arabidopsis showed oversensitive to abscisic acid (ABA) and salinity. The ABA-responsive gene ABI5 was up-regulated evidently in SbCRY1a transgenic lines, suggesting that SbCRY1a might regulate ABA signaling through the HY5-ABI5 regulon.

  15. Expression Analysis of Four Peroxiredoxin Genes from Tamarix hispida in Response to Different Abiotic Stresses and Exogenous Abscisic Acid (ABA

    Directory of Open Access Journals (Sweden)

    Guiyan Yang

    2012-03-01

    Full Text Available Peroxiredoxins (Prxs are a recently discovered family of antioxidant enzymes that catalyze the reduction of peroxides and alkyl peroxides. In this study, four Prx genes (named as ThPrxII, ThPrxIIE, ThPrxIIF, and Th2CysPrx were cloned from Tamarix hispida. Their expression profiles in response to stimulus of NaCl, NaHCO3, PEG, CdCl2 and abscisic acid (ABA in roots, stems and leaves of T. hispida were investigated using real-time RT-PCR. The results showed that the four ThPrxs were all expressed in roots, stems and leaves. Furthermore, the transcript levels of ThPrxIIE and ThPrxII were the lowest and the highest, respectively, in all tissue types. All the ThPrx genes were induced by both NaCl and NaHCO3 and reached their highest expression levels at the onset of stress in roots. Under PEG and CdCl2 stress, the expression patterns of these ThPrxs showed temporal and spatial specificity. The expressions of the ThPrxs were all differentially regulated by ABA, indicating that they are all involved in the ABA signaling pathway. These findings reveal a complex regulation of Prxs that is dependent on the type of Prx, tissue, and the signaling molecule. The divergence of the stress-dependent transcriptional regulation of the ThPrx gene family in T. hispida may provide an essential basis for the elucidation of Prx function in future work.

  16. Expression analysis of four peroxiredoxin genes from Tamarix hispida in response to different abiotic stresses and Exogenous Abscisic Acid (ABA).

    Science.gov (United States)

    Gao, Caiqiu; Zhang, Kaimin; Yang, Guiyan; Wang, Yucheng

    2012-01-01

    Peroxiredoxins (Prxs) are a recently discovered family of antioxidant enzymes that catalyze the reduction of peroxides and alkyl peroxides. In this study, four Prx genes (named as ThPrxII, ThPrxIIE, ThPrxIIF, and Th2CysPrx) were cloned from Tamarix hispida. Their expression profiles in response to stimulus of NaCl, NaHCO(3), PEG, CdCl(2) and abscisic acid (ABA) in roots, stems and leaves of T. hispida were investigated using real-time RT-PCR. The results showed that the four ThPrxs were all expressed in roots, stems and leaves. Furthermore, the transcript levels of ThPrxIIE and ThPrxII were the lowest and the highest, respectively, in all tissue types. All the ThPrx genes were induced by both NaCl and NaHCO(3) and reached their highest expression levels at the onset of stress in roots. Under PEG and CdCl(2) stress, the expression patterns of these ThPrxs showed temporal and spatial specificity. The expressions of the ThPrxs were all differentially regulated by ABA, indicating that they are all involved in the ABA signaling pathway. These findings reveal a complex regulation of Prxs that is dependent on the type of Prx, tissue, and the signaling molecule. The divergence of the stress-dependent transcriptional regulation of the ThPrx gene family in T. hispida may provide an essential basis for the elucidation of Prx function in future work.

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

    International Nuclear Information System (INIS)

    Hussain, S.; Saleem, M.F.; Cheema, M.A.; Ashraf, M.Y.; Haq, M.A.

    2010-01-01

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Abscisic acid (ABA) regulates grape bud dormancy, and dormancy release stimuli may act through modification of ABA metabolism.

    Science.gov (United States)

    Zheng, Chuanlin; Halaly, Tamar; Acheampong, Atiako Kwame; Takebayashi, Yumiko; Jikumaru, Yusuke; Kamiya, Yuji; Or, Etti

    2015-03-01

    In warm-winter regions, induction of dormancy release by hydrogen cyanamide (HC) is mandatory for commercial table grape production. Induction of respiratory stress by HC leads to dormancy release via an uncharacterized biochemical cascade that could reveal the mechanism underlying this phenomenon. Previous studies proposed a central role for abscisic acid (ABA) in the repression of bud meristem activity, and suggested its removal as a critical step in the HC-induced cascade. In the current study, support for these assumptions was sought. The data show that ABA indeed inhibits dormancy release in grape (Vitis vinifera) buds and attenuates the advancing effect of HC. However, HC-dependent recovery was detected, and was affected by dormancy status. HC reduced VvXERICO and VvNCED transcript levels and induced levels of VvABA8'OH homologues. Regulation of these central players in ABA metabolism correlated with decreased ABA and increased ABA catabolite levels in HC-treated buds. Interestingly, an inhibitor of ethylene signalling attenuated these effects of HC on ABA metabolism. HC also modulated the expression of ABA signalling regulators, in a manner that supports a decreased ABA level and response. Taken together, the data support HC-induced removal of ABA-mediated repression via regulation of ABA metabolism and signalling. Expression profiling during the natural dormancy cycle revealed that at maximal dormancy, the HC-regulated VvNCED1 transcript level starts to drop. In parallel, levels of VvA8H-CYP707A4 transcript and ABA catabolites increase sharply. This may provide initial support for the involvement of ABA metabolism also in the execution of natural dormancy. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  20. Variation in abscisic acid responsiveness of Aegilops tauschii and hexaploid wheat synthetics due to the D-genome diversity.

    Science.gov (United States)

    Iehisa, Julio C M; Takumi, Shigeo

    2012-01-01

    Common wheat (Triticum aestivum L.) is an allohexaploid that originated from natural hybridization between tetraploid wheat (Triticum turgidum) and diploid Aegilops tauschii. Ae. tauschii is considered one of the potential sources of new genetic variation in abiotic stress tolerance for improving common wheat. Abscisic acid (ABA) plays an important role in plant adaptation to environmental stresses. In this study, ABA responsiveness of 67 Ae. tauschii accessions and their synthetic hexaploid wheat lines, derived from crosses between T. turgidum cv. Langdon and the Ae. tauschii accessions, was evaluated based on growth inhibition by 20 µM ABA. Wide variation was found in ABA responsiveness for both synthetic wheat lines and their parental Ae. tauschii accessions. The variations due to D-genome found at the diploid level were also expressed in a hexaploid genetic background. Two pairs of synthetic wheat lines differing in ABA responsiveness were then selected for gene expression analysis and to test abiotic stress tolerance, because their parental Ae. tauschii accessions similarly exhibited the differential response to ABA. Gene expression of ABA inducible transcription factor, WABI5, and the downstream Cor/Lea genes (Wrab17, Wdhn13 and Wrab18) were analysed. In one pair, the highly responsive line exhibited higher induction of Wrab17 by ABA treatment, but no significant difference in dehydration or salinity tolerance was observed between these lines. In contrast, in the second pair, the highly ABA-responsive line showed higher levels of Wdhn13 expression and dehydration and salinity tolerance. In synthetic wheat lines, the difference in the ABA responsiveness of the lines appeared to be determined by the different sets of D-genome genes. Our findings suggest that highly ABA-responsive Ae. tauschii accessions should be valuable genetic resources for improving the abiotic stress tolerance of common wheat.

  1. Abscisic acid promotion of arbuscular mycorrhizal colonization requires a component of the PROTEIN PHOSPHATASE 2A complex.

    Science.gov (United States)

    Charpentier, Myriam; Sun, Jongho; Wen, Jiangqi; Mysore, Kirankumar S; Oldroyd, Giles E D

    2014-12-01

    Legumes can establish intracellular interactions with symbiotic microbes to enhance their fitness, including the interaction with arbuscular mycorrhizal (AM) fungi. AM fungi colonize root epidermal cells to gain access to the root cortex, and this requires the recognition by the host plant of fungus-made mycorrhizal factors. Genetic dissection has revealed the symbiosis signaling pathway that allows the recognition of AM fungi, but the downstream processes that are required to promote fungal infection are poorly understood. Abscisic acid (ABA) has been shown to promote arbuscule formation in tomato (Solanum lycopersicum). Here, we show that ABA modulates the establishment of the AM symbiosis in Medicago truncatula by promoting fungal colonization at low concentrations and impairing it at high concentrations. We show that the positive regulation of AM colonization via ABA requires a PROTEIN PHOSPHATASE 2A (PP2A) holoenzyme subunit, PP2AB'1. Mutations in PP2AB'1 cause reduced levels of AM colonization that cannot be rescued with permissive ABA application. The action of PP2AB'1 in response to ABA is unlinked to the generation of calcium oscillations, as the pp2aB'1 mutant displays a normal calcium response. This contrasts with the application of high concentrations of ABA that impairs mycorrhizal factor-induced calcium oscillations, suggesting different modes of action of ABA on the AM symbiosis. Our work reveals that ABA functions at multiple levels to regulate the AM symbiosis and that a PP2A phosphatase is required for the ABA promotion of AM colonization. © 2014 American Society of Plant Biologists. All Rights Reserved.

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

    KAUST Repository

    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.

  3. Functional roles of the pepper RING finger protein gene, CaRING1, in abscisic acid signaling and dehydration tolerance.

    Science.gov (United States)

    Lim, Chae Woo; Hwang, Byung Kook; Lee, Sung Chul

    2015-09-01

    Plants are constantly exposed to a variety of biotic and abiotic stresses, which include pathogens and conditions of high salinity, low temperature, and drought. Abscisic acid (ABA) is a major plant hormone involved in signal transduction pathways that mediate the defense response of plants to abiotic stress. Previously, we isolated Ring finger protein gene (CaRING1) from pepper (Capsicum annuum), which is associated with resistance to bacterial pathogens, accompanied by hypersensitive cell death. Here, we report a new function of the CaRING1 gene product in the ABA-mediated defense responses of plants to dehydration stress. The expression of the CaRING1 gene was induced in pepper leaves treated with ABA or exposed to dehydration or NaCl. Virus-induced gene silencing of CaRING1 in pepper plants exhibited low degree of ABA-induced stomatal closure and high levels of transpirational water loss in dehydrated leaves. These led to be more vulnerable to dehydration stress in CaRING1-silenced pepper than in the control pepper, accompanied by reduction of ABA-regulated gene expression and low accumulation of ABA and H2O2. In contrast, CaRING1-overexpressing transgenic plants showed enhanced sensitivity to ABA during the seedling growth and establishment. These plants were also more tolerant to dehydration stress than the wild-type plants because of high ABA accumulation, enhanced stomatal closure and increased expression of stress-responsive genes. Together, these results suggest that the CaRING1 acts as positive factor for dehydration tolerance in Arabidopsis by modulating ABA biosynthesis and ABA-mediated stomatal closing and gene expression.

  4. Abscinazole-E3M, a practical inhibitor of abscisic acid 8′-hydroxylase for improving drought tolerance

    Science.gov (United States)

    Takeuchi, Jun; Okamoto, Masanori; Mega, Ryosuke; Kanno, Yuri; Ohnishi, Toshiyuki; Seo, Mitsunori; Todoroki, Yasushi

    2016-01-01

    Abscisic acid (ABA) is an essential phytohormone that regulates plant water use and drought tolerance. However, agricultural applications of ABA have been limited because of its rapid inactivation in plants, which involves hydroxylation of ABA by ABA 8′-hydroxylase (CYP707A). We previously developed a selective inhibitor of CYP707A, (−)-Abz-E2B, by structurally modifying S-uniconazole, which functions as an inhibitor of CYP707A and as a gibberellin biosynthetic enzyme. However, its synthetic yield is too low for practical applications. Therefore, we designed novel CYP707A inhibitors, Abz-T compounds, that have simpler structures in which the 1,2,3-triazolyl ring of (−)-Abz-E2B has been replaced with a triple bond. They were successfully synthesised in shorter steps, resulting in greater yields than that of (−)-Abz-E2B. In the enzymatic assays, one of the Abz-T compounds, (−)-Abz-E3M, acted as a strong and selective inhibitor of CYP707A, similar to (−)-Abz-E2B. Analysis of the biological effects in Arabidopsis revealed that (−)-Abz-E3M enhanced ABA’s effects more than (−)-Abz-E2B in seed germination and in the expression of ABA-responsive genes. Treatment with (−)-Abz-E3M induced stomatal closure and improved drought tolerance in Arabidopsis. Furthermore, (−)-Abz-E3M also increased the ABA response in rice and maize. Thus, (−)-Abz-E3M is a more practical and effective inhibitor of CYP707A than (−)-Abz-E2B. PMID:27841331

  5. Abscinazole-E3M, a practical inhibitor of abscisic acid 8'-hydroxylase for improving drought tolerance.

    Science.gov (United States)

    Takeuchi, Jun; Okamoto, Masanori; Mega, Ryosuke; Kanno, Yuri; Ohnishi, Toshiyuki; Seo, Mitsunori; Todoroki, Yasushi

    2016-11-14

    Abscisic acid (ABA) is an essential phytohormone that regulates plant water use and drought tolerance. However, agricultural applications of ABA have been limited because of its rapid inactivation in plants, which involves hydroxylation of ABA by ABA 8'-hydroxylase (CYP707A). We previously developed a selective inhibitor of CYP707A, (-)-Abz-E2B, by structurally modifying S-uniconazole, which functions as an inhibitor of CYP707A and as a gibberellin biosynthetic enzyme. However, its synthetic yield is too low for practical applications. Therefore, we designed novel CYP707A inhibitors, Abz-T compounds, that have simpler structures in which the 1,2,3-triazolyl ring of (-)-Abz-E2B has been replaced with a triple bond. They were successfully synthesised in shorter steps, resulting in greater yields than that of (-)-Abz-E2B. In the enzymatic assays, one of the Abz-T compounds, (-)-Abz-E3M, acted as a strong and selective inhibitor of CYP707A, similar to (-)-Abz-E2B. Analysis of the biological effects in Arabidopsis revealed that (-)-Abz-E3M enhanced ABA's effects more than (-)-Abz-E2B in seed germination and in the expression of ABA-responsive genes. Treatment with (-)-Abz-E3M induced stomatal closure and improved drought tolerance in Arabidopsis. Furthermore, (-)-Abz-E3M also increased the ABA response in rice and maize. Thus, (-)-Abz-E3M is a more practical and effective inhibitor of CYP707A than (-)-Abz-E2B.

  6. Roles of Gibberellins and Abscisic Acid in Regulating Germination of Suaeda salsa Dimorphic Seeds Under Salt Stress.

    Science.gov (United States)

    Li, Weiqiang; Yamaguchi, Shinjiro; Khan, M Ajmal; An, Ping; Liu, Xiaojing; Tran, Lam-Son P

    2015-01-01

    Seed heteromorphism observed in many halophytes is an adaptive phenomenon toward high salinity. However, the relationship between heteromorphic seed germination and germination-related hormones under salt stress remains elusive. To gain an insight into this relationship, the roles of gibberellins (GAs) and abscisic acid (ABA) in regulating germination of Suaeda salsa dimorphic brown and black seeds under salinity were elucidated by studying the kinetics of the two hormones during germination of the two seed types with or without salinity treatment. Morphological analysis suggested that brown and black are in different development stage. The content of ABA was higher in dry brown than in black seeds, which gradually decreased after imbibition in water and salt solutions. Salt stress induced ABA accumulation in both germinating seed types, with higher induction effect on black than brown seeds. Black seeds showed lower germination percentage than brown seeds under both water and salt stress, which might be attributed to their higher ABA sensitivity rather than the difference in ABA content between black and brown seeds. Bioactive GA4 and its biosynthetic precursors showed higher levels in brown than in black seeds, whereas deactivated GAs showed higher content in black than brown seeds in dry or in germinating water or salt solutions. High salinity inhibited seed germination through decreasing the levels of GA4 in both seeds, and the inhibited effect of salt stress on GA4 level of black seeds was more profound than that of brown seeds. Taken together higher GA4 content, and lower ABA sensitivity contributed to the higher germination percentage of brown seeds than black seeds in water and salinity; increased ABA content and sensitivity, and decreased GA4 content by salinity were more profound in black than brown seeds, which contributed to lower germination of black seeds than brown seeds in salinity. The differential regulation of ABA and GA homeostases by salt

  7. Response of chickpea (Cicer arietinum L.) to terminal drought: leaf stomatal conductance, pod abscisic acid concentration, and seed set.

    Science.gov (United States)

    Pang, Jiayin; Turner, Neil C; Khan, Tanveer; Du, Yan-Lei; Xiong, Jun-Lan; Colmer, Timothy D; Devilla, Rosangela; Stefanova, Katia; Siddique, Kadambot H M

    2017-04-01

    Flower and pod production and seed set of chickpea (Cicer arietinum L.) are sensitive to drought stress. A 2-fold range in seed yield was found among a large number of chickpea genotypes grown at three dryland field sites in south-western Australia. Leaf water potential, photosynthetic characteristics, and reproductive development of two chickpea genotypes with contrasting yields in the field were compared when subjected to terminal drought in 106kg containers of soil in a glasshouse. The terminal drought imposed from early podding reduced biomass, reproductive growth, harvest index, and seed yield of both genotypes. Terminal drought at least doubled the percentage of flower abortion, pod abscission, and number of empty pods. Pollen viability and germination decreased when the fraction of transpirable soil water (FTSW) decreased below 0.18 (82% of the plant-available soil water had been transpired); however, at least one pollen tube in each flower reached the ovary. The young pods which developed from flowers produced when the FTSW was 0.50 had viable embryos, but contained higher abscisic acid (ABA) concentrations than those of the well-watered plants; all pods ultimately aborted in the drought treatment. Cessation of seed set at the same soil water content at which stomata began to close and ABA increased strongly suggested a role for ABA signalling in the failure to set seed either directly through abscission of developing pods or seeds or indirectly through the reduction of photosynthesis and assimilate supply to the seeds. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  8. HRS1 Acts as a Negative Regulator of Abscisic Acid Signaling to Promote Timely Germination of Arabidopsis Seeds

    Science.gov (United States)

    Wang, Ran; Liu, Hong; Yang, Huixia; Rodriguez, Pedro L.; Qin, Huanju; Liu, Xin; Wang, Daowen

    2012-01-01

    In this work, we conducted functional analysis of Arabidopsis HRS1 gene in order to provide new insights into the mechanisms governing seed germination. Compared with wild type (WT) control, HRS1 knockout mutant (hrs1-1) exhibited significant germination delays on either normal medium or those supplemented with abscisic acid (ABA) or sodium chloride (NaCl), with the magnitude of the delay being substantially larger on the latter media. The hypersensitivity of hrs1-1 germination to ABA and NaCl required ABI3, ABI4 and ABI5, and was aggravated in the double mutant hrs1-1abi1-2 and triple mutant hrs1-1hab1-1abi1-2, indicating that HRS1 acts as a negative regulator of ABA signaling during seed germination. Consistent with this notion, HRS1 expression was found in the embryo axis, and was regulated both temporally and spatially, during seed germination. Further analysis showed that the delay of hrs1-1 germination under normal conditions was associated with reduction in the elongation of the cells located in the lower hypocotyl (LH) and transition zone (TZ) of embryo axis. Interestingly, the germination rate of hrs1-1 was more severely reduced by the inhibitor of cell elongation, and more significantly decreased by the suppressors of plasmalemma H+-ATPase activity, than that of WT control. The plasmalemma H+-ATPase activity in the germinating seeds of hrs1-1 was substantially lower than that exhibited by WT control, and fusicoccin, an activator of this pump, corrected the transient germination delay of hrs1-1. Together, our data suggest that HRS1 may be needed for suppressing ABA signaling in germinating embryo axis, which promotes the timely germination of Arabidopsis seeds probably by facilitating the proper function of plasmalemma H+-ATPase and the efficient elongation of LH and TZ cells. PMID:22545134

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Visualisation of abscisic acid and 12-oxo-phytodienoic acid in immature Phaseolus vulgaris L. seeds using desorption electrospray ionisation-imaging mass spectrometry

    Science.gov (United States)

    Enomoto, Hirofumi; Sensu, Takuya; Sato, Kei; Sato, Futoshi; Paxton, Thanai; Yumoto, Emi; Miyamoto, Koji; Asahina, Masashi; Yokota, Takao; Yamane, Hisakazu

    2017-02-01

    The plant hormone abscisic acid (ABA) and the jasmonic acid related-compound 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development, dormancy, and germination. However, a lack of suitable techniques for visualising plant hormones has restricted the investigation of their biological mechanisms. In the present study, desorption electrospray ionisation-imaging mass spectrometry (DESI-IMS), a powerful tool for visualising metabolites in biological tissues, was used to visualise ABA and OPDA in immature Phaseolus vulgaris L. seed sections. The mass spectra, peak values and chemical formulae obtained from the analysis of seed sections were consistent with those determined for ABA and OPDA standards, as were the precursor and major fragment ions observed in tandem mass spectrometry (MS/MS) imaging. Furthermore, the precursor and fragment ion images showed similar distribution patterns. In addition, the localisation of ABA and OPDA using DESI-IMS was confirmed using liquid chromatography-MS/MS (LC-MS/MS). The results indicated that ABA was mainly distributed in the radical and cotyledon of the embryo, whereas OPDA was distributed exclusively in external structures, such as the hilum and seed coat. The present study is the first to report the visualisation of plant hormones using IMS, and demonstrates that DESI-IMS is a promising technique for future plant hormone research.

  11. Visualisation of abscisic acid and 12-oxo-phytodienoic acid in immature Phaseolus vulgaris L. seeds using desorption electrospray ionisation-imaging mass spectrometry.

    Science.gov (United States)

    Enomoto, Hirofumi; Sensu, Takuya; Sato, Kei; Sato, Futoshi; Paxton, Thanai; Yumoto, Emi; Miyamoto, Koji; Asahina, Masashi; Yokota, Takao; Yamane, Hisakazu

    2017-02-17

    The plant hormone abscisic acid (ABA) and the jasmonic acid related-compound 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development, dormancy, and germination. However, a lack of suitable techniques for visualising plant hormones has restricted the investigation of their biological mechanisms. In the present study, desorption electrospray ionisation-imaging mass spectrometry (DESI-IMS), a powerful tool for visualising metabolites in biological tissues, was used to visualise ABA and OPDA in immature Phaseolus vulgaris L. seed sections. The mass spectra, peak values and chemical formulae obtained from the analysis of seed sections were consistent with those determined for ABA and OPDA standards, as were the precursor and major fragment ions observed in tandem mass spectrometry (MS/MS) imaging. Furthermore, the precursor and fragment ion images showed similar distribution patterns. In addition, the localisation of ABA and OPDA using DESI-IMS was confirmed using liquid chromatography-MS/MS (LC-MS/MS). The results indicated that ABA was mainly distributed in the radical and cotyledon of the embryo, whereas OPDA was distributed exclusively in external structures, such as the hilum and seed coat. The present study is the first to report the visualisation of plant hormones using IMS, and demonstrates that DESI-IMS is a promising technique for future plant hormone research.

  12. Enterobacter sp. I-3, a bio-herbicide inhibits gibberellins biosynthetic pathway and regulates abscisic acid and amino acids synthesis to control plant growth.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Park, Jae-Man; Lee, In-Jung

    2016-12-01

    Very few bacterial species were identified as bio-herbicides for weed control. The present research was focused to elucidate the plant growth retardant properties of Enterobacter sp. I-3 during their interaction by determining the changes in endogenous photosynthetic pigments, plant hormones and amino acids. The two bacterial isolates I-4-5 and I-3 were used to select the superior bacterium for controlling weed seeds (Echinochloa crus-galli L. and Portulaca oleracea L.) germination. The post-inoculation of I-3 (Enterobacter sp. I-3) significantly inhibited the weeds seed germination than their controls. The mechanism of bacterium induced plant growth reduction was identified in lettuce treated with I-3 bacterium and compared their effects with known chemical herbicide, trinexapac-ethyl (TE). The treatment of I-3 and TE showed a significant inhibitory effect on shoot length, leaf number, leaf length, leaf width, shoot weight, root weight and chlorophyll content in lettuce seedlings. The endogenous gibberellins (GAs) and abscisic acid (ABA) analysis showed that Enterobacter sp. I-3 treated plants had lower levels of GAs (GA 12 , GA 19 , GA 20 and GA 8 ) and GAs/ABA ratio and then, the higher level of ABA when compared to their controls. Indeed, the individual amino acids ie., aspartic acid, glutamic acid, glycine, threonine, alanine, serine, leucine, isoleucine and tyrosine were declined in TE and I-3 exposed plants. Our results suggest that the utilization of Enterobacter sp. I-3 inhibits the GAs pathway and amino acids synthesis in weeds to control their growth can be an alternative to chemical herbicides. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Purification and determination of plant hormones auxin and abscisic acid using solid phase extraction and two-dimensional high performance liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Dobrev, Petre; Havlíček, Libor; Vágner, Martin; Malbeck, Jiří; Kamínek, Miroslav

    2005-01-01

    Roč. 1075, 1-2 (2005), s. 159-166 ISSN 0021-9673 R&D Projects: GA ČR GP522/02/D058; GA ČR GA206/02/0967; GA MŠk LN00A081; GA ČR GA522/04/0549; GA MZe QF4176 Institutional research plan: CEZ:AV0Z50380511 Keywords : Auxin * Abscisic acid * Solid phase extraction Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.096, year: 2005

  14. Local root abscisic acid (ABA) accumulation depends on the spatial distribution of soil moisture in potato: implications for ABA signalling under heterogeneous soil drying

    OpenAIRE

    Pu?rtolas, Jaime; Conesa, Mar?a R.; Ballester, Carlos; Dodd, Ian C.

    2014-01-01

    Patterns of root abscisic acid (ABA) accumulation ([ABA]root), root water potential (?root), and root water uptake (RWU), and their impact on xylem sap ABA concentration ([X-ABA]) were measured under vertical partial root-zone drying (VPRD, upper compartment dry, lower compartment wet) and horizontal partial root-zone drying (HPRD, two lateral compartments: one dry, the other wet) of potato (Solanum tuberosum L.). When water was withheld from the dry compartment for 0?10 d, RWU and ?root were...

  15. Molecular and physiological responses of Iranian Perennial ryegrass as affected by Trinexapac ethyl, Paclobutrazol and Abscisic acid under drought stress.

    Science.gov (United States)

    Sheikh Mohammadi, Mohammad Hossein; Etemadi, Nematollah; Arab, Mohammad Mehdi; Aalifar, Mostafa; Arab, Mostafa; Pessarakli, Mohammad

    2017-02-01

    Drought stress is the major limiting factor which affects turfgrass management in area with restricted rainfall or irrigation water supply. Trinexapac ethyl (TE), Paclobutrazol (PAC) and Abscisic acid (ABA) are three plant growth regulators (PGRs) that are commonly used on turf species for increasing their tolerance to different environmental stresses such as drought. However, little is known about the impact of PGRs on stress tolerance of Iranian Perennial ryegrass (Lolium perenne). The present study was conducted to examine the visual and physiological changes of Iranian Perennial ryegrass in response to foliar application of TE, PAC, and ABA under drought stress conditions. According to the obtained results, application of all three PGRs considerably restored visual quality of drought exposed plants. TE treatment increased chlorophyll content, proline content and resulted in less malondialdehyde (MDA) in drought stressed Perennial ryegrass. Application of all PGRs enhanced the relative water content (RWC) and decreased the electrolyte leakage (EL) and Hydrogen peroxide contents (H 2 O 2 content) of plants under drought stress, though the impact of TE was more pronounced. Throughout the experiment, TE- and ABA-treated plant showed greater soluble sugar (SSC) content as compared to the control. Antioxidant enzymes activities of drought exposed plants were considerably increased by PGRs application. Catalase (CAT) and Superoxide dismutase (SOD) activities were greater in TE-treated grasses followed by PAC-treated plants. Ascorbate peroxidase (APX) and peroxidase (POD) activities were significantly enhanced by TE and ABA application. The results of the present investigation suggest that application of TE, ABA and PAC enhances drought tolerance in Perennial ryegrass. TE, PAC and ABA were all effective in mitigating physiological damages resulting from drought stress, however the beneficial effects of TE were more pronounced. The result obtained of real time

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

    Directory of Open Access Journals (Sweden)

    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

  17. Interaction of Polyamines, Abscisic Acid, Nitric Oxide, and Hydrogen Peroxide under Chilling Stress in Tomato (Lycopersicon esculentumMill.) Seedlings.

    Science.gov (United States)

    Diao, Qiannan; Song, Yongjun; Shi, Dongmei; Qi, Hongyan

    2017-01-01

    Polyamines (PAs) play a vital role in the responses of higher plants to abiotic stresses. However, only a limited number of studies have examined the interplay between PAs and signal molecules. The aim of this study was to elucidate the cross-talk among PAs, abscisic acid (ABA), nitric oxide (NO), and hydrogen peroxide (H 2 O 2 ) under chilling stress conditions using tomato seedlings [( Lycopersicon esculentum Mill.) cv. Moneymaker]. The study showed that during chilling stress (4°C; 0, 12, and 24 h), the application of spermidine (Spd) and spermine (Spm) elevated NO and H 2 O 2 levels, enhanced nitrite reductase (NR), nitric oxide synthase (NOS)-like, and polyamine oxidase activities, and upregulated LeNR relative expression, but did not influence LeNOS1 expression. In contrast, putrescine (Put) treatment had no obvious impact. During the recovery period (25/15°C, 10 h), the above-mentioned parameters induced by the application of PAs were restored to their control levels. Seedlings pretreated with sodium nitroprusside (SNP, an NO donor) showed elevated Put and Spd levels throughout the treatment period, consistent with increased expression in leaves of genes encoding arginine decarboxylase ( LeADC. LeADC1 ), ornithine decarboxylase ( LeODC ), and Spd synthase ( LeSPDS ) expressions in tomato leaves throughout the treatment period. Under chilling stress, the Put content increased first, followed by a rise in the Spd content. Exogenously applied SNP did not increase the expression of genes encoding S -adenosylmethionine decarboxylase ( LeSAMDC ) and Spm synthase ( LeSPMS ), consistent with the observation that Spm levels remained constant under chilling stress and during the recovery period. In contrast, exogenous Put significantly increased the ABA content and the 9- cis -epoxycarotenoid dioxygenase ( LeNCED1 ) transcript level. Treatment with ABA could alleviate the electrolyte leakage (EL) induced by D-Arg (an inhibitor of Put). Taken together, it is

  18. Arabidopsis Glutamate Receptor Homolog3.5 Modulates Cytosolic Ca2+ Level to Counteract Effect of Abscisic Acid in Seed Germination1[OPEN

    Science.gov (United States)

    Kong, Dongdong; Ju, Chuanli; Parihar, Aisha; Kim, So; Cho, Daeshik; Kwak, June M.

    2015-01-01

    Seed germination is a critical step in a plant’s life cycle that allows successful propagation and is therefore strictly controlled by endogenous and environmental signals. However, the molecular mechanisms underlying germination control remain elusive. Here, we report that the Arabidopsis (Arabidopsis thaliana) glutamate receptor homolog3.5 (AtGLR3.5) is predominantly expressed in germinating seeds and increases cytosolic Ca2+ concentration that counteracts the effect of abscisic acid (ABA) to promote germination. Repression of AtGLR3.5 impairs cytosolic Ca2+ concentration elevation, significantly delays germination, and enhances ABA sensitivity in seeds, whereas overexpression of AtGLR3.5 results in earlier germination and reduced seed sensitivity to ABA. Furthermore, we show that Ca2+ suppresses the expression of ABSCISIC ACID INSENSITIVE4 (ABI4), a key transcription factor involved in ABA response in seeds, and that ABI4 plays a fundamental role in modulation of Ca2+-dependent germination. Taken together, our results provide molecular genetic evidence that AtGLR3.5-mediated Ca2+ influx stimulates seed germination by antagonizing the inhibitory effects of ABA through suppression of ABI4. These findings establish, to our knowledge, a new and pivotal role of the plant glutamate receptor homolog and Ca2+ signaling in germination control and uncover the orchestrated modulation of the AtGLR3.5-mediated Ca2+ signal and ABA signaling via ABI4 to fine-tune the crucial developmental process, germination, in Arabidopsis. PMID:25681329

  19. Use of abscisic acid, mannitol and salt concentration decrease in the culture medium in the in vitro conservation of Ipomoea batatas

    Directory of Open Access Journals (Sweden)

    Angel Espinosa Reyes

    2002-01-01

    Full Text Available Nodal segment from in vitro plants of Jewel clone sweet potato were culture in the following culture medias: a Murashige and Skoog (1962 salts supplemented with abscisic acid (0.0, 1.0, 5.0 y 10.0 mg.l-1, b Murashige and Skoog (1962 salts supplemented with mannitol (0.0, 10.0 15.0 y 20.0 g.l-1 and c different Murashige and Skoog (1962 salts concentration (100, 75, 50 and 25% were used. Survival during conservation was high in all experiment. The 5.0 and 10.0 mg.l-1 abscisic acid strongly inhibited the plants growth. It was reached a decrease of growth when using mannitol in the culture medium. The media with 25% and 50% MS salts concentration caused a low of plants growth. When cultured in fresh culture medium it was achieved a high recovery ratio of conserved material. Key words: sweet potato, minimal growth, phyto resources, biodiversity

  20. Regulation of erucic acid accumulation in oilseed rape (Brassica napus L.) : effects of temperature and abscisic acid

    NARCIS (Netherlands)

    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

  1. Identification and characterization of the abscisic acid (ABA) receptor gene family and its expression in response to hormones in the rubber tree.

    Science.gov (United States)

    Guo, Dong; Zhou, Ying; Li, Hui-Liang; Zhu, Jia-Hong; Wang, Ying; Chen, Xiong-Ting; Peng, Shi-Qing

    2017-03-23

    Abscisic acid (ABA) is an essential phytohormone involved in diverse physiological processes. Although genome-wide analyses of the ABA receptor PYR/PYL/RCAR (PYL) protein/gene family have been performed in certain plant species, little is known about the ABA receptor protein/gene family in the rubber tree (Hevea brasiliensis). In this study, we identified 14 ABA receptor PYL proteins/genes (designated HbPYL1 through HbPYL14) in the most recent rubber tree genome. A phylogenetic tree was constructed, which demonstrated that HbPYLs can be divided into three subfamilies that correlate well with the corresponding Arabidopsis subfamilies. Eight HbPYLs are highly expressed in laticifers. Five of the eight genes are simultaneously regulated by ABA, jasmonic acid (JA) and ethylene (ET). The identification and characterization of HbPYLs should enable us to further understand the role of ABA signal in the rubber tree.

  2. 1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds.

    Science.gov (United States)

    Hermann, Katrin; Meinhard, Juliane; Dobrev, Peter; Linkies, Ada; Pesek, Bedrich; Hess, Barbara; Machácková, Ivana; Fischer, Uwe; Leubner-Metzger, Gerhard

    2007-01-01

    The control of sugar beet (Beta vulgaris L.) germination by plant hormones was studied by comparing fruits and seeds. Treatment of sugar beet fruits and seeds with gibberellins, brassinosteroids, auxins, cytokinins, and jasmonates or corresponding hormone biosynthesis inhibitors did not appreciably affect radicle emergence of fruits or seeds. By contrast, treatment with ethylene or the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) promoted radicle emergence of fruits and seeds. Abscisic acid (ABA) acted as an antagonist of ethylene and inhibited radicle emergence of seeds, but not appreciably of fruits. High endogenous contents of ACC and of ABA were evident in seeds and pericarps of dry mature fruits, but declined early during imbibition. ABA-treatment of seeds and fruits induced seed ACC accumulation while ACC-treatment did not affect the seed ABA content. Transcripts of ACC oxidase (ACO, ethylene-forming enzyme) and ABA 8'-hydroxylase (CYP707A, ABA-degrading enzyme) accumulate in fruits and seeds upon imbibition. ABA and ACC and the pericarp did not affect the seed CYP707A transcript levels. By contrast, seed ACO transcript accumulation was promoted by ABA and by pericarp removal, but not by ACC. Quantification of the endogenous ABA and ACC contents, ABA and ACC leaching, and ethylene evolution, demonstrate that an embryo-mediated active ABA extrusion system is involved in keeping the endogenous seed ABA content low by 'active ABA leaching', while the pericarp restricts ACC leaching during imbibition. Sugar beet radicle emergence appears to be controlled by the pericarp, by ABA and ACC leaching, and by an ABA-ethylene antagonism that affects ACC biosynthesis and ACO gene expression.

  3. Abscisic Acid Promotes Susceptibility to the Rice Leaf Blight Pathogen Xanthomonas oryzae pv oryzae by Suppressing Salicylic Acid-Mediated Defenses.

    Directory of Open Access Journals (Sweden)

    Jing Xu

    Full Text Available The plant hormone abscisic acid (ABA is involved in a wide variety of plant processes, including the initiation of stress-adaptive responses to various environmental cues. Recently, ABA also emerged as a central factor in the regulation and integration of plant immune responses, although little is known about the underlying mechanisms. Aiming to advance our understanding of ABA-modulated disease resistance, we have analyzed the impact, dynamics and interrelationship of ABA and the classic defense hormone salicylic acid (SA during progression of rice infection by the leaf blight pathogen Xanthomonas oryzae pv. oryzae (Xoo. Consistent with ABA negatively regulating resistance to Xoo, we found that exogenously administered ABA renders rice hypersusceptible to infection, whereas chemical and genetic disruption of ABA biosynthesis and signaling, respectively, led to enhanced Xoo resistance. In addition, we found successful Xoo infection to be associated with extensive reprogramming of ABA biosynthesis and response genes, suggesting that ABA functions as a virulence factor for Xoo. Interestingly, several lines of evidence indicate that this immune-suppressive effect of ABA is due at least in part to suppression of SA-mediated defenses that normally serve to limit pathogen growth. Resistance induced by the ABA biosynthesis inhibitor fluridone, however, appears to operate in a SA-independent manner and is likely due to induction of non-specific physiological stress. Collectively, our findings favor a scenario whereby virulent Xoo hijacks the rice ABA machinery to cause disease and highlight the importance of ABA and its crosstalk with SA in shaping the outcome of rice-Xoo interactions.

  4. Arabidopsis AtDjA3 null mutant shows increased sensitivity to abscisic acid, salt, and osmotic stress in germination and postgermination stages

    Directory of Open Access Journals (Sweden)

    Silvia eSalas-Muñoz

    2016-02-01

    Full Text Available DnaJ proteins are essential co-chaperones involved in abiotic and biotic stress responses. Arabidopsis AtDjA3 gene encodes a molecular co-chaperone of 420 amino acids, which belongs to the J-protein family. In this study, we report the functional characterization of the AtDjA3 gene using the Arabidopsis knockout line designated j3 and the 35S::AtDjA3 overexpression lines. Loss of AtDjA3 function was associated with small seed production. In fact, j3 mutant seeds showed a reduction of 24% in seed weight compared to Col-0 seeds. Expression analysis showed that the AtDjA3 gene was modulated in response to NaCl, glucose, and abscisic acid. The j3 line had increased sensitivity to NaCl and glucose treatments in the germination and cotyledon development in comparison to parental Col-0. Furthermore, the j3 mutant line exhibited higher abscisic acid sensitivity in comparison to parental Col-0 and 35S::AtDjA3 overexpression lines. In addition, we examined the expression of ABI3 gene, which is a central regulator in ABA signalling, in j3 mutant and 35S::AtDjA3 overexpression lines. Under 5 μM ABA treatment at 24 h, j3 mutant seedlings displayed higher ABI3 expression, whereas in 35S::AtDjA3 overexpression lines, ABI3 gene expression was repressed. Taken together, these results demonstrate that the AtDjA3 gene is involved in seed development and abiotic stress tolerance.

  5. An ultrahigh-performance liquid chromatography method with electrospray ionization tandem mass spectrometry for simultaneous quantification of five phytohormones in medicinal plant Glycyrrhiza uralensis under abscisic acid stress.

    Science.gov (United States)

    Xiang, Yu; Song, Xiaona; Qiao, Jing; Zang, Yimei; Li, Yanpeng; Liu, Yong; Liu, Chunsheng

    2015-07-01

    An efficient simplified method was developed to determine multiple classes of phytohormones simultaneously in the medicinal plant Glycyrrhiza uralensis. Ultrahigh-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS) with multiple reaction monitoring (MRM) in negative mode was used for quantification. The five studied phytohormones are gibberellic acid (GA3), abscisic acid (ABA), jasmonic acid (JA), indole-3-acetic acid, and salicylic acid (SA). Only 100 mg of fresh leaves was needed, with one purification step based on C18 solid-phase extraction. Cinnamic acid was chosen as the internal standard instead of isotope-labeled internal standards. Under the optimized conditions, the five phytohormones with internal standard were separated within 4 min, with good linearities and high sensitivity. The validated method was applied to monitor the spatial and temporal changes of the five phytohormones in G. uralensis under ABA stress. The levels of GA3, ABA, JA, and SA in leaves of G. uralensis were increased at different times and with different tendencies in the reported stress mode. These changes in phytohormone levels are discussed in the context of a possible feedback regulation mechanism. Understanding this mechanism will provide a good chance of revealing the mutual interplay between different biosynthetic routes, which could further help elucidate the mechanisms of effective composition accumulation in medicinal plants.

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

    Science.gov (United States)

    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. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

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

    Science.gov (United States)

    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. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

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

    KAUST Repository

    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.

  9. A mutation in the Arabidopsis HYL1 gene encoding a dsRNA binding protein affects responses to abscisic acid, auxin, and cytokinin

    Science.gov (United States)

    Lu, C.; Fedoroff, N.

    2000-01-01

    Both physiological and genetic evidence indicate interconnections among plant responses to different hormones. We describe a pleiotropic recessive Arabidopsis transposon insertion mutation, designated hyponastic leaves (hyl1), that alters the plant's responses to several hormones. The mutant is characterized by shorter stature, delayed flowering, leaf hyponasty, reduced fertility, decreased rate of root growth, and an altered root gravitropic response. It also exhibits less sensitivity to auxin and cytokinin and hypersensitivity to abscisic acid (ABA). The auxin transport inhibitor 2,3,5-triiodobenzoic acid normalizes the mutant phenotype somewhat, whereas another auxin transport inhibitor, N-(1-naph-thyl)phthalamic acid, exacerbates the phenotype. The gene, designated HYL1, encodes a 419-amino acid protein that contains two double-stranded RNA (dsRNA) binding motifs, a nuclear localization motif, and a C-terminal repeat structure suggestive of a protein-protein interaction domain. We present evidence that the HYL1 gene is ABA-regulated and encodes a nuclear dsRNA binding protein. We hypothesize that the HYL1 protein is a regulatory protein functioning at the transcriptional or post-transcriptional level.

  10. Abscisic acid-induced nitric oxide and proline accumulation in independent pathways under water-deficit stress during seedling establishment in Medicago truncatula.

    Science.gov (United States)

    Planchet, Elisabeth; Verdu, Isabelle; Delahaie, Julien; Cukier, Caroline; Girard, Clément; Morère-Le Paven, Marie-Christine; Limami, Anis M

    2014-05-01

    Nitric oxide (NO) production and amino acid metabolism modulation, in particular abscisic acid (ABA)-dependent proline accumulation, are stimulated in planta by most abiotic stresses. However, the relationship between NO production and proline accumulation under abiotic stress is still poorly understood, especially in the early phases of plant development. To unravel this question, this work investigated the tight relationship between NO production and proline metabolism under water-deficit stress during seedling establishment. Endogenous nitrate reductase-dependent NO production in Medicago truncatula seedlings increased in a time-dependent manner after short-term water-deficit stress. This water-deficit-induced endogenous NO accumulation was mediated through a ABA-dependent pathway and accompanied by an inhibition of seed germination, a loss of water content, and a decrease in elongation of embryo axes. Interestingly, a treatment with a specific NO scavenger (cPTIO) alleviated these water-deficit detrimental effects. However, the content of total amino acids, in particular glutamate and proline, as well as the expression of genes encoding enzymes of synthesis and degradation of proline were not affected by cPTIO treatment under water-deficit stress. Under normal conditions, exogenous NO donor stimulated neither the expression of P5CS2 nor the proline content, as observed after PEG treatment. These results strongly suggest that the modulation of proline metabolism is independent of NO production under short-term water-deficit stress during seedling establishment.

  11. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance

    Science.gov (United States)

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

    2016-01-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana. Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 K372E with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network. PMID:27406784

  12. The ribosomal small-subunit protein S28 gene from Helianthus annuus (Asteraceae) is down-regulated in response to drought, high salinity, and abscisic acid.

    Science.gov (United States)

    Liu, Xianan; Baird, W Vance

    2003-04-01

    A partial cDNA for the ribosomal S28 gene from sunflower was initially cloned and identified to be down-regulated by high salinity, using differential display reverse transcriptase-polymerase chain reaction (PCR). Using this sequence, a 502-base pair (bp) full-length cDNA was cloned by rapid amplification of cDNA ends. This cDNA (designated Ha-RPS28) encodes a protein component of the small subunit of cytoplasmic ribosomes. The predicted 65 amino acid residue sequence of Ha-RPS28, with an estimated molecular mass of 7.5 kD, has 92, 89, and 86% identity with the S28 ribosomal proteins from peach, maize, and Arabidopsis, respectively. Ha-RPS28 was expressed in all organs examined, and the highest level was detected in fully expanded leaves. Furthermore, expression of Ha-RPS28 was down-regulated in both seedling roots and shoots in response to drought, high salinity, or abscisic acid.

  13. Development and Validation of a Reversed-Phase Liquid Chromatography Method for the Simultaneous Determination of Indole-3-Acetic Acid, Indole-3-Pyruvic Acid, and Abscisic Acid in Barley (Hordeum vulgare L.).

    Science.gov (United States)

    Nakurte, Ilva; Keisa, Anete; Rostoks, Nils

    2012-01-01

    A simple, sensitive, precise, and specific reverse HPLC method was developed and validated for the determination of plant hormones in barley (Hordeum vulgare L.). The method includes extraction in aqueous organic solvent followed by solid-phase extraction, sample evaporation, and reversed-phase HPLC analysis in a general purpose UV-visible (abscisic acid (ABA)) and fluorescence detection (indole-3-acetic acid (IAA) and indole-3-pyruvic acid (IPA)), high-performance liquid chromatography system. The separation was carried out on Zorbax Eclipse XDB C8 column (150  ×  4.6  mm I.D) with a mobile phase composed of methanol and 1% acetic acid (60 : 40 v/v) in isocratic mode at a flow rate of 1 ml min(-1). The detection was monitored at 270 nm (ABA) and at 282 nm (Ex) and 360 nm (Em) (IAA, IPA). The developed method was validated in terms of accuracy, precision, linearity, limit of detection, limit of quantification, and robustness. The determined validation parameters are in the commonly acceptable ranges for that kind of analysis.

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

    Science.gov (United States)

    Lu, Yandu; Tarkowská, Danuše; Turečková, Veronika; Luo, Tingwei; Xin, Yi; Li, Jing; Wang, Qintao; Jiao, Nianzhi; Strnad, Miroslav; Xu, Jian

    2014-10-01

    The origin of phytohormones is poorly understood, and their physiological roles in microalgae remain elusive. Genome comparison of photosynthetic autotrophic eukaryotes has revealed that the biosynthetic pathways of abscisic acid (ABA) and cytokinins (CKs) emerged in unicellular algae. While ABA and CK degradation mechanisms emerged broadly in algal lineages, complete vascular plant-type conjugation pathways emerged prior to the rise of Streptophyta. In microalgae, a complete set of proteins from the canonical ABA and CK sensing and signaling pathways is not essential, but individual components are present, suggesting stepwise recruitment of phytohormone signaling components. In the oleaginous eustigmatophyte Nannochloropsis oceanica IMET1, UHPLC-MS/MS detected a wide array of plant hormones, despite a phytohormone profile that is very distinct from that of flowering plants. Time-series transcriptional analysis during nitrogen depletion revealed activation of the ABA biosynthetic pathway and antagonistic transcription of CK biosynthetic genes. Correspondingly, the ABA level increases while the dominant bioactive CK forms decrease. Moreover, exogenous CKs stimulate cell-cycle progression while exogenous ABA acts as both an algal growth repressor and a positive regulator in response to stresses. The presence of such functional flowering plant-like phytohormone signaling systems in Nannochloropsis sp. suggests a much earlier origin of phytohormone biosynthesis and degradation than previously believed, and supports the presence in microalgae of as yet unknown conjugation and sensing/signaling systems that may be exploited for microalgal feedstock development. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  15. Malbec grape (Vitis vinifera L.) responses to the environment: Berry phenolics as influenced by solar UV-B, water deficit and sprayed abscisic acid.

    Science.gov (United States)

    Alonso, Rodrigo; Berli, Federico J; Fontana, Ariel; Piccoli, Patricia; Bottini, Rubén

    2016-12-01

    High-altitude vineyards receive elevated solar ultraviolet-B (UV-B) levels so producing high quality berries for winemaking because of induction in the synthesis of phenolic compounds. Water deficit (D) after veraison, is a commonly used tool to regulate berry polyphenols concentration in red wine cultivars. Abscisic acid (ABA) plays a crucial role in the acclimation to environmental factors/signals (including UV-B and D). The aim of the present study was to evaluate independent and interactive effects of high-altitude solar UV-B, moderate water deficit and ABA applications on Vitis vinifera cv. Malbec berries. The experiment was conducted during two growing seasons with two treatments of UV-B (+UV-B and -UV-B), watering (+D and -D) and ABA (+ABA and -ABA), in a factorial design. Berry fresh weight, sugar content, fruit yield, phenolic compounds profile and antioxidant capacity (ORAC) were analyzed at harvest. Previous incidence of high UV-B prevented deleterious effects of water deficit, i.e. berry weight reduction and diminution of sugar accumulation. High UV-B increased total phenols (mainly astilbin, quercetin and kaempferol) and ORAC, irrespectively of the combination with other factors. Fruit yield was reduced by combining water deficit and high UV-B or water deficit and ABA. Two applications of ABA were enough to induced biochemical changes increasing total anthocyanins, especially those with higher antioxidant capacity. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  16. Exogenous Abscisic Acid Promotes Anthocyanin Biosynthesis and Increased Expression of Flavonoid Synthesis Genes in Vitis vinifera × Vitis labrusca Table Grapes in a Subtropical Region

    Directory of Open Access Journals (Sweden)

    Renata Koyama

    2018-03-01

    Full Text Available Hybrid (Vitis vinifera ×Vitis labrusca table grape cultivars grown in the subtropics often fail to accumulate sufficient anthocyanins to achieve good uniform berry color. Growers of V. vinifera table grapes in temperate regions generally use ethephon and, more recently, (S-cis-abscisic acid (S-ABA to overcome this problem. The objective of this study was to determine if S-ABA applications at different timings and concentrations have an effect on anthocyanin regulatory and biosynthetic genes, pigment accumulation, and berry color of the Selection 21 cultivar, a new V. vinifera ×V. labrusca hybrid seedless grape that presents lack of red color when grown in subtropical areas. Applications of S-ABA 400 mg/L resulted in a higher accumulation of total anthocyanins and of the individual anthocyaninsanthocyanins: delphinidin-3-glucoside, cyanidin-3-glucoside, peonidin-3-glucoside, and malvidin-3-glucoside in the berry skin and improved the color attributes of the berries. Treatment with two applications at 7 days after véraison (DAV and 21 DAV of S-ABA 400 mg/L resulted in a higher accumulation of total anthocyanins in the skin of berries and increased the gene expression of CHI, F3H, DFR, and UFGT and of the VvMYBA1 and VvMYBA2 transcription factors in the seedless grape cultivar.

  17. Exogenous Abscisic Acid Promotes Anthocyanin Biosynthesis and Increased Expression of Flavonoid Synthesis Genes in Vitis vinifera × Vitis labrusca Table Grapes in a Subtropical Region

    Science.gov (United States)

    Koyama, Renata; Roberto, Sergio R.; de Souza, Reginaldo T.; Borges, Wellington F. S.; Anderson, Mauri; Waterhouse, Andrew L.; Cantu, Dario; Fidelibus, Matthew W.; Blanco-Ulate, Barbara

    2018-01-01

    Hybrid (Vitis vinifera ×Vitis labrusca) table grape cultivars grown in the subtropics often fail to accumulate sufficient anthocyanins to achieve good uniform berry color. Growers of V. vinifera table grapes in temperate regions generally use ethephon and, more recently, (S)-cis-abscisic acid (S-ABA) to overcome this problem. The objective of this study was to determine if S-ABA applications at different timings and concentrations have an effect on anthocyanin regulatory and biosynthetic genes, pigment accumulation, and berry color of the Selection 21 cultivar, a new V. vinifera ×V. labrusca hybrid seedless grape that presents lack of red color when grown in subtropical areas. Applications of S-ABA 400 mg/L resulted in a higher accumulation of total anthocyanins and of the individual anthocyaninsanthocyanins: delphinidin-3-glucoside, cyanidin-3-glucoside, peonidin-3-glucoside, and malvidin-3-glucoside in the berry skin and improved the color attributes of the berries. Treatment with two applications at 7 days after véraison (DAV) and 21 DAV of S-ABA 400 mg/L resulted in a higher accumulation of total anthocyanins in the skin of berries and increased the gene expression of CHI, F3H, DFR, and UFGT and of the VvMYBA1 and VvMYBA2 transcription factors in the seedless grape cultivar. PMID:29632542

  18. Persistent negative temperature response of mesophyll conductance in red raspberry (Rubus idaeus L.) leaves under both high and low vapour pressure deficits: a role for abscisic acid?

    Science.gov (United States)

    Qiu, Changpeng; Ethier, Gilbert; Pepin, Steeve; Dubé, Pascal; Desjardins, Yves; Gosselin, André

    2017-09-01

    The temperature dependence of mesophyll conductance (g m ) was measured in well-watered red raspberry (Rubus idaeus L.) plants acclimated to leaf-to-air vapour pressure deficit (VPDL) daytime differentials of contrasting amplitude, keeping a fixed diurnal leaf temperature (T leaf ) rise from 20 to 35 °C. Contrary to the great majority of g m temperature responses published to date, we found a pronounced reduction of g m with increasing T leaf irrespective of leaf chamber O 2 level and diurnal VPDL regime. Leaf hydraulic conductance was greatly enhanced during the warmer afternoon periods under both low (0.75 to 1.5 kPa) and high (0.75 to 3.5 kPa) diurnal VPDL regimes, unlike stomatal conductance (g s ), which decreased in the afternoon. Consequently, the leaf water status remained largely isohydric throughout the day, and therefore cannot be evoked to explain the diurnal decrease of g m . However, the concerted diurnal reductions of g m and g s were well correlated with increases in leaf abscisic acid (ABA) content, thus suggesting that ABA can induce a significant depression of g m under favourable leaf water status. Our results challenge the view that the temperature dependence of g m can be explained solely from dynamic leaf anatomical adjustments and/or from the known thermodynamic properties of aqueous solutions and lipid membranes.​. © 2017 John Wiley & Sons Ltd.

  19. Expression analysis of nine small heat shock protein genes from Tamarix hispida in response to different abiotic stresses and abscisic acid treatment.

    Science.gov (United States)

    Yang, Guiyan; Wang, Yucheng; Zhang, Kaimin; Gao, Caiqiu

    2014-03-01

    Heat shock proteins (HSPs) play important roles in protecting plants against environmental stresses. Furthermore, small heat shock proteins (sHSPs) are the most ubiquitous HSP subgroup with molecular weights ranging from 15 to 42 kDa. In this study, nine sHSP genes (designated as ThsHSP1-9) were cloned from Tamarix hispida. Their expression patterns in response to cold, heat shock, NaCl, PEG and abscisic acid (ABA) treatments were investigated in the roots and leaves of T. hispida by real-time RT-PCR analysis. The results showed that most of the nine ThsHSP genes were expressed at higher levels in roots than in leaves under normal growth condition. All of ThsHSP genes were highly induced under conditions of cold (4 °C) and different heat shocks (36, 40, 44, 48 and 52 °C). Under NaCl stress, all nine ThsHSPs genes were up-regulated at least one stress time-point in both roots and leaves. Under PEG and ABA treatments, the nine ThsHSPs showed various expression patterns, indicating a complex regulation pathway among these genes. This study represents an important basis for the elucidation of ThsHSP gene function and provides essential information that can be used for stress tolerance genetic engineering in future studies.

  20. A SHATTERPROOF-like gene controls ripening in non-climacteric strawberries, and auxin and abscisic acid antagonistically affect its expression.

    Science.gov (United States)

    Daminato, Margherita; Guzzo, Flavia; Casadoro, Giorgio

    2013-09-01

    Strawberries (Fragaria×ananassa) are false fruits the ripening of which follows the non-climacteric pathway. The role played by a C-type MADS-box gene [SHATTERPROOF-like (FaSHP)] in the ripening of strawberries has been studied by transiently modifying gene expression through either over-expression or RNA-interference-mediated down-regulation. The altered expression of the FaSHP gene caused a change in the time taken by the over-expressing and the down- regulated fruits to attain the pink stage, which was slightly shorter and much longer, respectively, compared to controls. In parallel with the modified ripening times, the metabolome components and the expression of ripening-related genes also appeared different in the transiently modified fruits. Differences in the response time of the analysed genes suggest that FaSHP can control the expression of ripening genes either directly or indirectly through other transcription factor-encoding genes. Because fleshy strawberries are false fruits these results indicate that C-type MADS-box genes like SHATTERPROOF may act as modulators of ripening in fleshy fruit-like structures independently of their anatomical origin. Treatment of strawberries with either auxin or abscisic acid had antagonistic impacts on both the expression of FaSHP and the expression of ripening-related genes and metabolome components.

  1. Gladiolus hybridus ABSCISIC ACID INSENSITIVE 5 (GhABI5) is an important transcription factor in ABA signaling that can enhance Gladiolus corm dormancy and Arabidopsis seed dormancy

    Science.gov (United States)

    Wu, Jian; Seng, Shanshan; Sui, Juanjuan; Vonapartis, Eliana; Luo, Xian; Gong, Benhe; Liu, Chen; Wu, Chenyu; Liu, Chao; Zhang, Fengqin; He, Junna; Yi, Mingfang

    2015-01-01

    The phytohormone abscisic acid (ABA) regulates plant development and is crucial for abiotic stress response. In this study, cold storage contributes to reducing endogenous ABA content, resulting in dormancy breaking of Gladiolus. The ABA inhibitor fluridone also promotes germination, suggesting that ABA is an important hormone that regulates corm dormancy. Here, we report the identification and functional characterization of the Gladiolus ABI5 homolog (GhABI5), which is a basic leucine zipper motif transcriptional factor (TF). GhABI5 is expressed in dormant vegetative organs (corm, cormel, and stolon) as well as in reproductive organs (stamen), and it is up-regulated by ABA or drought. Complementation analysis reveals that GhABI5 rescues the ABA insensitivity of abi5-3 during seed germination and induces the expression of downstream ABA response genes in Arabidopsis thaliana (EM1, EM6, and RD29B). Down-regulation of GhABI5 in dormant cormels via virus induced gene silence promotes sprouting and reduces the expression of downstream genes (GhLEA and GhRD29B). The results of this study reveal that GhABI5 regulates bud dormancy (vegetative organ) in Gladiolus in addition to its well-studied function in Arabidopsis seeds (reproductive organ). PMID:26579187

  2. Differential expression of gibberellin- and abscisic acid-related genes implies their roles in the bud activity-dormancy transition of tea plants.

    Science.gov (United States)

    Yue, Chuan; Cao, Hongli; Hao, Xinyuan; Zeng, Jianming; Qian, Wenjun; Guo, Yuqiong; Ye, Naixing; Yang, Yajun; Wang, Xinchao

    2018-03-01

    Thirty genes involved in GA and ABA metabolism and signalling were identified, and the expression profiles indicated that they play crucial roles in the bud activity-dormancy transition in tea plants. Gibberellin (GA) and abscisic acid (ABA) are fundamental phytohormones that extensively regulate plant growth and development, especially bud dormancy and sprouting transition in perennial plants. However, there is little information on GA- and ABA-related genes and their expression profiles during the activity-dormancy transition in tea plants. In the present study, 30 genes involved in the metabolism and signalling pathways of GA and ABA were first identified, and their expression patterns in different tissues were assessed. Further evaluation of the expression patterns of selected genes in response to GA 3 and ABA application showed that CsGA3ox, CsGA20ox, CsGA2ox, CsZEP and CsNCED transcripts were differentially expressed after exogenous treatment. The expression profiles of the studied genes during winter dormancy and spring sprouting were investigated, and somewhat diverse expression patterns were found for GA- and ABA-related genes. This diversity was associated with the bud activity-dormancy cycle of tea plants. These results indicate that the genes involved in the metabolism and signalling of GA and ABA are important for regulating the bud activity-dormancy transition in tea plants.

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

    Science.gov (United States)

    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. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  4. Resistance to Botrytis cinerea in sitiens, an abscisic acid-deficient tomato mutant, involves timely production of hydrogen peroxide and cell wall modifications in the epidermis.

    Science.gov (United States)

    Asselbergh, Bob; Curvers, Katrien; Franca, Soraya C; Audenaert, Kris; Vuylsteke, Marnik; Van Breusegem, Frank; Höfte, Monica

    2007-08-01

    Plant defense mechanisms against necrotrophic pathogens, such as Botrytis cinerea, are considered to be complex and to differ from those that are effective against biotrophs. In the abscisic acid-deficient sitiens tomato (Solanum lycopersicum) mutant, which is highly resistant to B. cinerea, accumulation of hydrogen peroxide (H(2)O(2)) was earlier and stronger than in the susceptible wild type at the site of infection. In sitiens, H(2)O(2) accumulation was observed from 4 h postinoculation (hpi), specifically in the leaf epidermal cell walls, where it caused modification by protein cross-linking and incorporation of phenolic compounds. In wild-type tomato plants, H(2)O(2) started to accumulate 24 hpi in the mesophyll layer and was associated with spreading cell death. Transcript-profiling analysis using TOM1 microarrays revealed that defense-related transcript accumulation prior to infection was higher in sitiens than in wild type. Moreover, further elevation of sitiens defense gene expression was stronger than in wild type 8 hpi both in number of genes and in their expression levels and confirmed a role for cell wall modification in the resistant reaction. Although, in general, plant defense-related reactive oxygen species formation facilitates necrotrophic colonization, these data indicate that timely hyperinduction of H(2)O(2)-dependent defenses in the epidermal cell wall can effectively block early development of B. cinerea.

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

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

    Liu, Y.; Li, T.; Yang, C.

    2015-01-01

    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)

  7. Abscisic Acid Stimulates Glucagon-Like Peptide-1 Secretion from L-Cells and Its Oral Administration Increases Plasma Glucagon-Like Peptide-1 Levels in Rats.

    Science.gov (United States)

    Bruzzone, Santina; Magnone, Mirko; Mannino, Elena; Sociali, Giovanna; Sturla, Laura; Fresia, Chiara; Booz, Valeria; Emionite, Laura; De Flora, Antonio; Zocchi, Elena

    2015-01-01

    In recent years, Abscisic Acid (ABA) has been demonstrated to be involved in the regulation of glucose homeostasis in mammals as an endogenous hormone, by stimulating both insulin release and peripheral glucose uptake. In addition, ABA is released by glucose- or GLP-1-stimulated β-pancreatic cells. Here we investigated whether ABA can stimulate GLP-1 release. The human enteroendocrine L cell line hNCI-H716 was used to explore whether ABA stimulates in vitro GLP-1 secretion and/or transcription. ABA induced GLP-1 release in hNCI-H716 cells, through a cAMP/PKA-dependent mechanism. ABA also enhanced GLP-1 transcription. In addition, oral administration of ABA significantly increased plasma GLP-1 and insulin levels in rats. In conclusion, ABA can stimulate GLP-1 release: this result and the previous observation that GLP-1 stimulates ABA release from β -cells, suggest a positive feed-back mechanism between ABA and GLP-1, regulating glucose homeostasis. Type 2 diabetes treatments targeting the GLP-1 axis by either inhibiting its rapid clearance by dipeptidyl-peptidase IV or using GLP-1 mimetics are currently used. Moreover, the development of treatments aimed at stimulating GLP-1 release from L cells has been considered as an alternative approach. Accordingly, our finding that ABA increases GLP-1 release in vitro and in vivo may suggest ABA and/or ABA analogs as potential anti-diabetic treatments.

  8. Abscisic Acid Stimulates Glucagon-Like Peptide-1 Secretion from L-Cells and Its Oral Administration Increases Plasma Glucagon-Like Peptide-1 Levels in Rats.

    Directory of Open Access Journals (Sweden)

    Santina Bruzzone

    Full Text Available In recent years, Abscisic Acid (ABA has been demonstrated to be involved in the regulation of glucose homeostasis in mammals as an endogenous hormone, by stimulating both insulin release and peripheral glucose uptake. In addition, ABA is released by glucose- or GLP-1-stimulated β-pancreatic cells. Here we investigated whether ABA can stimulate GLP-1 release. The human enteroendocrine L cell line hNCI-H716 was used to explore whether ABA stimulates in vitro GLP-1 secretion and/or transcription. ABA induced GLP-1 release in hNCI-H716 cells, through a cAMP/PKA-dependent mechanism. ABA also enhanced GLP-1 transcription. In addition, oral administration of ABA significantly increased plasma GLP-1 and insulin levels in rats. In conclusion, ABA can stimulate GLP-1 release: this result and the previous observation that GLP-1 stimulates ABA release from β -cells, suggest a positive feed-back mechanism between ABA and GLP-1, regulating glucose homeostasis. Type 2 diabetes treatments targeting the GLP-1 axis by either inhibiting its rapid clearance by dipeptidyl-peptidase IV or using GLP-1 mimetics are currently used. Moreover, the development of treatments aimed at stimulating GLP-1 release from L cells has been considered as an alternative approach. Accordingly, our finding that ABA increases GLP-1 release in vitro and in vivo may suggest ABA and/or ABA analogs as potential anti-diabetic treatments.

  9. Acclimation mechanisms elicited by sprayed abscisic acid, solar UV-B and water deficit in leaf tissues of field-grown grapevines.

    Science.gov (United States)

    Alonso, Rodrigo; Berli, Federico J; Bottini, Rubén; Piccoli, Patricia

    2015-06-01

    The independent and interactive effects of solar ultraviolet-B radiation (UV-B), moderate water deficit and sprayed abscisic acid (ABA) on leaves gas exchange and biochemical aspects of field-grown grapevines of the cv. Malbec were investigated in a high altitude vineyard (1450 m a.s.l.). Two UV-B treatments (ambient solar UV-B or reduced UV-B), two watering treatments (well watered or moderate water deficit) and two ABA treatments (no ABA and sprayed ABA) were given alone and combined in a factorial design. Gas exchange and photosynthesis were reduced by water deficit and highly impaired in the UV-B and water deficit combined treatment. UV-absorbing compounds were stimulated independently by UV-B. The monoterpenes α-pinene, 3-carene and terpinolene, and the sesquiterpene nerolidol were augmented by UV-B, water deficit or sprayed ABA. Levels of the triterpene squalene and the diterpene phytol were significantly higher in the treatment that combined UV-B, water deficit and ABA applications. Environment signals (solar UV-B and moderate water deficit) and sprayed ABA elicited mechanisms of acclimation by augmenting the content of terpenes with antioxidant and antifungal properties, thus enhancing the plant defensive mechanisms towards signals both biotic and abiotic. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  10. Overexpression of EsMcsu1 from the halophytic plant Eutrema salsugineum promotes abscisic acid biosynthesis and increases drought resistance in alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Zhou, C; Ma, Z Y; Zhu, L; Guo, J S; Zhu, J; Wang, J F

    2015-12-17

    The stress phytohormone abscisic acid (ABA) plays pivotal roles in plants' adaptive responses to adverse environments. Molybdenum cofactor sulfurases influence aldehyde oxidase activity and ABA biosynthesis. In this study, we isolated a novel EsMcsu1 gene encoding a molybdenum cofactor sulfurase from Eutrema salsugineum. EsMcus1 transcriptional patterns varied between organs, and its expression was significantly upregulated by abiotic stress or ABA treatment. Alfalfa plants that overexpressed EsMcsu1 had a higher ABA content than wild-type (WT) plants under drought stress conditions. Furthermore, levels of reactive oxygen species (ROS), ion leakage, and malondialdehyde were lower in the transgenic plants than in the WT plants after drought treatment, suggesting that the transgenic plants experienced less ROS-mediated damage. However, the expression of several stress-responsive genes, antioxidant enzyme activity, and osmolyte (proline and total soluble sugar) levels in the transgenic plants were higher than those in the WT plants after drought treatment. Therefore, EsMcsu1 overexpression improved drought tolerance in alfalfa plants by activating a series of ABA-mediated stress responses.

  11. Simultaneous treatment with tebuconazole and abscisic acid induces drought and salinity stress tolerance in Arabidopsis thaliana by maintaining key plastid protein levels.

    Science.gov (United States)

    Horn, Ruth; Chudobova, Ivana; Hänsel, Ulrike; Herwartz, Denise; Koskull-Döring, Pascal von; Schillberg, Stefan

    2013-03-01

    Arabidopsis thaliana plants were treated simultaneously with the fungicide tebuconazole and the phytohormone abscisic acid (ABA). We carried out comparative proteomic and transcriptomic analysis against untreated controls under different stress regimes. The chemicals were applied 24 h before the onset of drought stress (removal of the nutrient medium) or salinity stress (hydroponic culture using 150 mM NaCl), and samples were taken during the stress treatments and after a 24 h recovery period. The combined chemical treatment protected plants against both forms of stress. Difference in-gel electrophoresis revealed 18 and 34 unique protein markers representing induced tolerance to drought and salinity stress, respectively. Most of the markers represented plastid functions (such as CO(2) fixation and photosystem II activity), and their abundance was reduced under stress conditions but maintained at near normal levels in the treated plants. The corresponding transcripts were reduced in abundance primarily under drought stress but not salinity stress, indicating that the signal transduction pathways activated by tebuconazole/ABA treatment depend on the nature of the stress stimulus.

  12. Induction of protection against paraquat-induced oxidative damage by abscisic acid in maize leaves is mediated through mitogen-activated protein kinase.

    Science.gov (United States)

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

    2009-10-01

    Mitogen-activated protein kinase (MAPK) cascade has been shown to be important components in stress signal transduction 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.

  13. Proteomic Identification of Annexins, Calcium-Dependent Membrane Binding Proteins That Mediate Osmotic Stress and Abscisic Acid Signal Transduction in Arabidopsis

    Science.gov (United States)

    Lee, Sumin; Lee, Eun Jung; Yang, Eun Ju; Lee, Ji Eun; Park, Ae Ran; Song, Won Hyun; Park, Ohkmae K.

    2004-01-01

    Comparative proteomic analysis of the Arabidopsis thaliana root microsomal fraction was performed to identify novel components of salt stress signaling. Among the salt-responsive microsomal proteins, two spots that increased upon salt treatment on a two-dimensional gel were identified as the same protein, designated annexin 1 (AnnAt1). Annexins comprise a multigene family of Ca2+-dependent membrane binding proteins and have been extensively studied in animal cells. AnnAt1 is strongly expressed in root but rarely in flower tissue. In this study, the results suggest that salt stress induces translocation from the cytosol to the membrane and potential turnover of existing protein. This process is blocked by EGTA treatment, implying that AnnAt1 functions in stress response are tightly associated with Ca2+. T-DNA insertion mutants of annAt1 and a different isoform, annAt4, displayed hypersensitivity to osmotic stress and abscisic acid (ABA) during germination and early seedling growth. The results collectively suggest that AnnAt1 and AnnAt4 play important roles in osmotic stress and ABA signaling in a Ca2+-dependent manner. PMID:15161963

  14. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance.

    Science.gov (United States)

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

    2016-09-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 (K372E) with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  15. Relationship among color development, anthocyanin and pigment-related gene expression in 'Crimson Seedless' grapes treated with abscisic acid and sucrose.

    Science.gov (United States)

    Olivares, Daniela; Contreras, Carolina; Muñoz, Victoria; Rivera, Sebastián; González-Agüero, Mauricio; Retamales, Julio; Defilippi, Bruno G

    2017-06-01

    'Crimson Seedless' is one of the most important table grape varieties in Chile, but under certain environmental conditions, the fruit exhibits inadequate red color development, causing economic losses due to lower product quality. The use of plant growth regulators, such as abscisic acid (ABA) and ethylene, during development increases the anthocyanin content of the skin, improving the color of the berry. Recently, sucrose has been identified as a signaling molecule capable of regulating the expression of genes of the anthocyanin biosynthesis pathway. The aim of this study was to analyze the effect of application of ABA and/or sucrose on color development and their relationship with anthocyanin metabolism. Applications of ABA (400 ppm or 200 ppm) and/or sucrose (90 mM) were performed close to the véraison stage. During development and at harvest, quality attributes such as berry firmness, total soluble solids and titratable acidity were not affected by these treatments. Increased red color development was observed in fruits treated with ABA and/or sucrose, due to accumulation of anthocyanins. Fruits subjected to sucrose treatment showed higher levels of anthocyanins than untreated fruits but lower levels than fruits treated with ABA. Increased expression of genes involved in anthocyanin biosynthesis was observed in ABA- and sucrose-treated fruits compared to untreated fruits. Based on these findings, we demonstrated that sucrose improved fruit color development by increasing synthesis and accumulation of anthocyanins, thus allowing earlier harvests and improving table grape quality. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Overexpression of a Protein Phosphatase 2C from Beech Seeds in Arabidopsis Shows Phenotypes Related to Abscisic Acid Responses and Gibberellin Biosynthesis1

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    Reyes, David; Rodríguez, Dolores; González-García, Mary Paz; Lorenzo, Oscar; Nicolás, Gregorio; García-Martínez, José Luis; Nicolás, Carlos

    2006-01-01

    A functional abscisic acid (ABA)-induced protein phosphatase type 2C (PP2C) was previously isolated from beech (Fagus sylvatica) seeds (FsPP2C2). Because transgenic work is not possible in beech, in this study we overexpressed this gene in Arabidopsis (Arabidopsis thaliana) to provide genetic evidence on FsPP2C2 function in seed dormancy and other plant responses. In contrast with other PP2Cs described so far, constitutive expression of FsPP2C2 in Arabidopsis, under the cauliflower mosaic virus 35S promoter, produced enhanced sensitivity to ABA and abiotic stress in seeds and vegetative tissues, dwarf phenotype, and delayed flowering, and all these effects were reversed by gibberellic acid application. The levels of active gibberellins (GAs) were reduced in 35S:FsPP2C2 plants, although transcript levels of AtGA20ox1 and AtGA3ox1 increased, probably as a result of negative feedback regulation, whereas the expression of GASA1 was induced by GAs. Additionally, FsPP2C2-overexpressing plants showed a strong induction of the Responsive to ABA 18 (RAB18) gene. Interestingly, FsPP2C2 contains two nuclear targeting sequences, and transient expression assays revealed that ABA directed this protein to the nucleus. Whereas other plant PP2Cs have been shown to act as negative regulators, our results support the hypothesis that FsPP2C2 is a positive regulator of ABA. Moreover, our results indicate the existence of potential cross-talk between ABA signaling and GA biosynthesis. PMID:16815952

  17. Effects of Ethephon and Abscisic Acid Application on Ripening-Related Genes in ‘Kohi’ Kiwifruit (Actinidia chinensis on the Vine

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    Kongsuwan Ampa

    2017-01-01

    Full Text Available The effects of ethephon and abscisic acid (ABA application on ripening-related genes of pre-harvest ‘Kohi’ kiwifruit (Actinidia chinensis were studied to clarify the possibility of the fruit ripening on the vine. The fruits were treated on the vine at mature stage with 250 µL⋅L−1 ethephon or 100 µmol⋅L−1 ABA, and the expression levels of chlorophyll synthase (AcCLS, chlorophyllase1 (AcCLH1, polygalacturonase (AcPG, expansin (AcEXP, β-amylase (Acβ-AM, sucrose synthase (AcSUSY, MADS-box SEPALLATA4/RIPENING INHIBITOR-like (AcSEP4/RIN and FRUITFUL-like (AcTDR4/FUL genes were analyzed. The expression levels of AcPG, AcEXP, Acβ-AM, and AcSUSY increased in the ethephon-treated fruit, but those of AcCLH1 at 6 and 9 days after treatment and AcCLS decreased. Moreover, the expression levels of AcSEP4/RIN and AcTDR4/FUL, the latter of which is associated with ethylene biosynthesis, were higher in the ethephon-treated fruit. The expression level of each gene in ABA-treated fruit was not significantly different from that of the untreated control. The results suggest that ethephon application increases the expression levels of AcPG, AcEXP, Acβ-AM, AcSUSY, AcSEP4/RIN, and AcTDR4/FUL in ‘Kohi’ kiwifruit on the vine.

  18. Age-related mechanism and its relationship with secondary metabolism and abscisic acid in Aristotelia chilensis plants subjected to drought stress.

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    González-Villagra, Jorge; Rodrigues-Salvador, Acácio; Nunes-Nesi, Adriano; Cohen, Jerry D; Reyes-Díaz, Marjorie M

    2018-03-01

    Drought stress is the most important stress factor for plants, being the main cause of agricultural crop loss in the world. Plants have developed complex mechanisms for preventing water loss and oxidative stress such as synthesis of abscisic acid (ABA) and non-enzymatic antioxidant compounds such as anthocyanins, which might help plants to cope with abiotic stress as antioxidants and for scavenging reactive oxygen species. A. chilensis (Mol.) is a pioneer species, colonizing and growing on stressed and disturbed environments. In this research, an integrated analysis of secondary metabolism in Aristotelia chilensis was done to relate ABA effects on anthocyanins biosynthesis, by comparing between young and fully-expanded leaves under drought stress. Plants were subjected to drought stress for 20 days, and physiological, biochemical, and molecular analyses were performed. The relative growth rate and plant water status were reduced in stressed plants, with young leaves significantly more affected than fully-expanded leaves beginning from the 5th day of drought stress. A. chilensis plants increased their ABA and total anthocyanin content and showed upregulation of gene expression when they were subjected to severe drought (day 20), with these effects being higher in fully-expanded leaves. Multivariate analysis indicated a significant positive correlation between transcript levels for NCED1 (9-cis-epoxycarotenoid dioxygenase) and UFGT (UDP glucose: flavonoid-3-O-glucosyltransferase) with ABA and total anthocyanin, respectively. Thus, this research provides a more comprehensive analysis of the mechanisms that allow plants to cope with drought stress. This is highlighted by the differences between young and fully-expanded leaves, showing different sensibility to stress due to their ability to synthesize anthocyanins. In addition, this ability to synthesize different and high amounts of anthocyanins could be related to higher NCED1 and MYB expression and ABA levels

  19. Evaluating the involvement and interaction of abscisic acid and miRNA156 in the induction of anthocyanin biosynthesis in drought-stressed plants.

    Science.gov (United States)

    González-Villagra, Jorge; Kurepin, Leonid V; Reyes-Díaz, Marjorie M

    2017-08-01

    ABA is involved in anthocyanin synthesis through the regulation of microRNA156, augmenting the level of expression of anthocyanin synthesis-related genes and, therefore, increasing anthocyanin level. Drought stress is the main cause of agricultural crop loss in the world. However, plants have developed mechanisms that allow them to tolerate drought stress conditions. At cellular level, drought stress induces changes in metabolite accumulation, including increases in anthocyanin levels due to upregulation of the anthocyanin biosynthetic pathway. Recent studies suggest that the higher anthocyanin content observed under drought stress conditions could be a consequence of a rise in the abscisic acid (ABA) concentration. This plant hormone crosses the plasma membrane by specific transporters, and it is recognized at the cytosolic level by receptors known as pyrabactin resistance (PYR)/regulatory component of ABA receptors (PYR/RCARs) that regulate downstream components. In this review, we discuss the hypothesis regarding the involvement of ABA in the regulation of microRNA156 (miRNA156), which is upregulated as part of dehydration stress responsiveness in different species. The miRNA156 upregulation produces a greater level of anthocyanin gene expression, forming the multienzyme complex that will synthesize an increased level of anthocyanins at the cytosolic face of the rough endoplasmic reticulum (RER). After synthesis, anthocyanins are transported from the RER to the vacuole by two possible models of transport: (1) membrane vesicle-mediated transport, or (2) membrane transporter-mediated transport. Thus, the aim was to analyze the recent findings on synthesis, transport and the possible mechanism by which ABA could increase anthocyanin synthesis under drought stress conditions potentially throughout microRNA156 (miRNA156).

  20. Exogenous abscisic acid application decreases cadmium accumulation in Arabidopsis plants, which is associated with the inhibition of IRT1-mediated cadmium uptake

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    Shi Kan eFan

    2014-12-01

    Full Text Available Cadmium (Cd contamination of agricultural soils is an increasingly serious problem. Measures need to be developed to minimise Cd entering the human food chain from contaminated soils. We report here that, under Cd exposure condition, application with low doses of (0.1–0.5 μM abscisic acid (ABA clearly inhibited Cd uptake by roots and decreased Cd level in Arabidopsis wild-type plants (Col-0. Expression of IRT1 in roots was also strongly inhibited by ABA treatment. Decrease in Cd uptake and the inhibition of IRT1 expression were clearly lesser pronounced in an ABA-insensitive double mutant snrk2.2/2.3 than in the Col-0 in response to ABA application. The ABA-decreased Cd uptake was found to correlate with the ABA-inhibited IRT1 expression in the roots of Col-0 plants fed two different levels of iron. Furthermore, the Cd uptake of irt1 mutants was barely affected by ABA application. These results indicated that inhibition of IRT1 expression is involved in the decrease of Cd uptake in response to exogenous ABA application. Interestingly, ABA application increased the iron level in both Col-0 plants and irt1 mutants, suggesting that ABA-increased Fe acquisition does not depend on the IRT1 function, but on the contrary, the ABA-mediated inhibition of IRT1 expression may be due to the elevation of iron level in plants. From our results, we concluded that ABA application might increase iron acquisition, followed by the decrease in Cd uptake by inhibition of IRT1 activity. Thus, for crop production in Cd contaminated soils, developing techniques based on ABA application potentially is a promising approach for reducing Cd accumulation in edible organs in plants.

  1. Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress.

    Science.gov (United States)

    Chen, Han; Lai, Zhibing; Shi, Junwei; Xiao, Yong; Chen, Zhixiang; Xu, Xinping

    2010-12-19

    WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. We report that the three WRKYs are involved in plant responses to abscisic acid (ABA) and abiotic stress. Through analysis of single, double, and triple mutants and overexpression lines for the WRKY genes, we have shown that WRKY18 and WRKY60 have a positive effect on plant ABA sensitivity for inhibition of seed germination and root growth. The same two WRKY genes also enhance plant sensitivity to salt and osmotic stress. WRKY40, on the other hand, antagonizes WRKY18 and WRKY60 in the effect on plant sensitivity to ABA and abiotic stress in germination and growth assays. Both WRKY18 and WRKY40 are rapidly induced by ABA, while induction of WRKY60 by ABA is delayed. ABA-inducible expression of WRKY60 is almost completely abolished in the wrky18 and wrky40 mutants. WRKY18 and WRKY40 recognize a cluster of W-box sequences in the WRKY60 promoter and activate WRKY60 expression in protoplasts. Thus, WRKY60 might be a direct target gene of WRKY18 and WRKY40 in ABA signaling. Using a stable transgenic reporter/effector system, we have shown that both WRKY18 and WRKY60 act as weak transcriptional activators while WRKY40 is a transcriptional repressor in plant cells. We propose that the three related WRKY transcription factors form a highly interacting regulatory network that modulates gene expression in both plant defense and stress responses by acting as either transcription activator or repressor.

  2. Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress

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    Chen Zhixiang

    2010-12-01

    Full Text Available Abstract Background WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. Results We report that the three WRKYs are involved in plant responses to abscisic acid (ABA and abiotic stress. Through analysis of single, double, and triple mutants and overexpression lines for the WRKY genes, we have shown that WRKY18 and WRKY60 have a positive effect on plant ABA sensitivity for inhibition of seed germination and root growth. The same two WRKY genes also enhance plant sensitivity to salt and osmotic stress. WRKY40, on the other hand, antagonizes WRKY18 and WRKY60 in the effect on plant sensitivity to ABA and abiotic stress in germination and growth assays. Both WRKY18 and WRKY40 are rapidly induced by ABA, while induction of WRKY60 by ABA is delayed. ABA-inducible expression of WRKY60 is almost completely abolished in the wrky18 and wrky40 mutants. WRKY18 and WRKY40 recognize a cluster of W-box sequences in the WRKY60 promoter and activate WRKY60 expression in protoplasts. Thus, WRKY60 might be a direct target gene of WRKY18 and WRKY40 in ABA signaling. Using a stable transgenic reporter/effector system, we have shown that both WRKY18 and WRKY60 act as weak transcriptional activators while WRKY40 is a transcriptional repressor in plant cells. Conclusions We propose that the three related WRKY transcription factors form a highly interacting regulatory network that modulates gene expression in both plant defense and stress responses by acting as either transcription activator or repressor.

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

    International Nuclear Information System (INIS)

    Liu, Xin; Zhu, Yanming; Zhai, Hong; Cai, Hua; Ji, Wei; Luo, Xiao; Li, Jing; Bai, Xi

    2012-01-01

    Highlights: ► AtPP2CG1 positively regulates salt tolerance in ABA-dependent manner. ► AtPP2CG1 up-regulates the expression of marker genes in different pathways. ► 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.

  4. Gene Expression and Metabolite Profiling of Developing Highbush Blueberry Fruit Indicates Transcriptional Regulation of Flavonoid Metabolism and Activation of Abscisic Acid Metabolism1[W][OA

    Science.gov (United States)

    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

  5. The synthesis and accumulation of resveratrol are associated with veraison and abscisic acid concentration in Beihong (Vitis vinifera × Vitis amurensis berry skin

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    Junfang Wang

    2016-11-01

    Full Text Available Resveratrols are polyphenolic secondary metabolites that can benefit human health, and only occur in a few plant families including Vitaceae. It has been reported that abscisic acid (ABA can induce veraison (the onset of grape berry ripening and may induce the accumulation of resveratrol in berry skin. However, the relationships between ABA, veraison, the accumulation of anthocyanins and the accumulation of resveratrol in the berry are poorly understood. This study attempted to answer this question through an investigation of the effect of applied ABA and fluridone (a synthetic inhibitor of ABA on the biosynthesis and accumulation of ABA, anthocyanin and resveratrol in Beihong (Vitis vinifera × Vitis amurensis berry skin. Under natural conditions, resveratrol concentration was very low before 91 DAA (days after anthesis, i.e. 2 weeks after veraison, however, it increased sharply from this point to 126 DAA (maturity. Exogenous ABA applications all resulted in an increase in berry skin ABA and anthocyanin concentration, irrespective of the developmental stage at which the treatment occurred (20 and 10 d pre-veraison,veraison or 7 d post-veraison, thereby advancing veraison. In contrast, resveratrol concentration increased only when ABA was applied at 10 d pre-veraison or at veraison. As a result, the accumulation of resveratrol was associated with veraison in grape berry skin and this accumulation, together with that of anthocyanins, was associated with ABA concentration. The response of resveratrol biosynthesis in the berry skin to manipulation of ABA varied during berry development and was less sensitive to ABA than the response of anthocyanin biosynthesis.

  6. Storage behavior and changes in concentrations of abscisic acid and gibberellins during dormancy break and germination in seeds of Phellodendron amurense var. wilsonii (Rutaceae).

    Science.gov (United States)

    Chen, Shun-Ying; Chien, Ching-Te; Baskin, Jerry M; Baskin, Carol C

    2010-02-01

    The medicinal Asian plant genus Phellodendron is known to contain several very important compounds that have biological action. The main purpose of this study was to determine whether seeds of Phellodendron amurense var. wilsonii can be stored and to characterize their dormancy. Seeds of this taxon stored at -20 and -80 degrees C and in liquid nitrogen retained their high germinability, indicating that they have orthodox storage behavior. Intact seeds from freshly collected fruits were dormant and required 12 weeks of cold stratification at 4 degrees C for complete germination. Scarifying the seed coat was partially effective in breaking seed dormancy. Exogenous gibberellins (GA(3), GA(4) and GA(4+7)) promoted germination of scarified seeds, GA(4) and GA(4+7) being more effective than GA(3). Fluridone, an abscisic acid (ABA) biosynthesis inhibitor, was efficient in breaking dormancy, but it was less effective than GA(4) or GA(4+7) alone. Paclobutrazol, a GA biosynthesis inhibitor, inhibited seed germination, and the inhibitory effect was reversed completely by GA(4) and by GA(4+7). ABA content of seeds subjected to cold stratification or to incubation at 35/10 degrees C, which enhanced seed germination, was reduced about four- to sixfold compared to that of fresh seeds. Higher concentrations of GA(3), GA(4) and GA(7) were detected in nondormant seeds and in seeds with an emerged radicle than in fresh seeds. Present results seem to indicate that dormancy in P. amurense var. wilsonii seeds is imposed partially by the seed coat and partially by high ABA content. ABA content decreased and GA(3), GA(4) and GA(7) content increased during germination.

  7. Effects of abscisic acid, ethylene and sugars on the mobilization of storage proteins and carbohydrates in seeds of the tropical tree Sesbania virgata (Leguminosae).

    Science.gov (United States)

    Tonini, Patricia Pinho; Purgatto, Eduardo; Buckeridge, Marcos Silveira

    2010-10-01

    Endospermic legumes are abundant in tropical forests and their establishment is closely related to the mobilization of cell-wall storage polysaccharides. Endosperm cells also store large numbers of protein bodies that play an important role as a nitrogen reserve in this seed. In this work, a systems approach was adopted to evaluate some of the changes in carbohydrates and hormones during the development of seedlings of the rain forest tree Sesbania virgata during the period of establishment. Seeds imbibed abscisic acid (ABA), glucose and sucrose in an atmosphere of ethylene, and the effects of these compounds on the protein contents, α-galactosidase activity and endogenous production of ABA and ethylene by the seeds were observed. The presence of exogenous ABA retarded the degradation of storage protein in the endosperm and decreased α-galactosidase activity in the same tissue during galactomannan degradation, suggesting that ABA represses enzyme action. On the other hand, exogenous ethylene increased α-galactosidase activity in both the endosperm and testa during galactomannan degradation, suggesting an inducing effect of this hormone on the hydrolytic enzymes. Furthermore, the detection of endogenous ABA and ethylene production during the period of storage mobilization and the changes observed in the production of these endogenous hormones in the presence of glucose and sucrose, suggested a correlation between the signalling pathway of these hormones and the sugars. These findings suggest that ABA, ethylene and sugars play a role in the control of the hydrolytic enzyme activities in seeds of S. virgata, controlling the process of storage degradation. This is thought to ensure a balanced flow of the carbon and nitrogen for seedling development.

  8. Genome-wide gene expression profiling in Arabidopsis thaliana reveals new targets of abscisic acid and largely impaired gene regulation in the abi1-1 mutant.

    Science.gov (United States)

    Hoth, Stefan; Morgante, Michele; Sanchez, Juan-Pablo; Hanafey, Michael K; Tingey, Scott V; Chua, Nam-Hai

    2002-12-15

    The phytohormone abscisic acid (ABA) plays important regulatory roles in many plant developmental processes including seed dormancy, germination, growth, and stomatal movements. These physiological responses to ABA are in large part brought about by changes in gene expression. To study genome-wide ABA-responsive gene expression we applied massively parallel signature sequencing (MPSS) to samples from Arabidopsis thaliana wildtype (WT) and abi1-1 mutant seedlings. We identified 1354 genes that are either up- or downregulated following ABA treatment of WT seedlings. Among these ABA-responsive genes, many encode signal transduction components. In addition, we identified novel ABA-responsive gene families including those encoding ribosomal proteins and proteins involved in regulated proteolysis. In the ABA-insensitive mutant abi1-1, ABA regulation of about 84.5% and 6.9% of the identified genes was impaired or strongly diminished, respectively; however, 8.6% of the genes remained appropriately regulated. Compared to other methods of gene expression analysis, the high sensitivity and specificity of MPSS allowed us to identify a large number of ABA-responsive genes in WT Arabidopsis thaliana. The database given in our supplementary material (http://jcs.biologists.org/supplemental) provides researchers with the opportunity to rapidly assess whether genes of interest may be regulated by ABA. Regulation of the majority of the genes by ABA was impaired in the ABA-insensitive mutant abi1-1. However, a subset of genes continued to be appropriately regulated by ABA, which suggests the presence of at least two ABA signaling pathways, only one of which is blocked in abi1-1.

  9. CCCH-type zinc finger family in maize: genome-wide identification, classification and expression profiling under abscisic acid and drought treatments.

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    Xiaojian Peng

    Full Text Available BACKGROUND: CCCH-type zinc finger proteins comprise a large protein family. Increasing evidence suggests that members of this family are RNA-binding proteins with regulatory functions in mRNA processing. Compared with those in animals, functions of CCCH-type zinc finger proteins involved in plant growth and development are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Here, we performed a genome-wide survey of CCCH-type zinc finger genes in maize (Zea mays L. by describing the gene structure, phylogenetic relationships and chromosomal location of each family member. Promoter sequences and expression profiles of putative stress-responsive members were also investigated. A total of 68 CCCH genes (ZmC3H1-68 were identified in maize and divided into seven groups by phylogenetic analysis. These 68 genes were found to be unevenly distributed on 10 chromosomes with 15 segmental duplication events, suggesting that segmental duplication played a major role in expansion of the maize CCCH family. The Ka/Ks ratios suggested that the duplicated genes of the CCCH family mainly experienced purifying selection with limited functional divergence after duplication events. Twelve maize CCCH genes grouped with other known stress-responsive genes from Arabidopsis were found to contain putative stress-responsive cis-elements in their promoter regions. Seven of these genes chosen for further quantitative real-time PCR analysis showed differential expression patterns among five representative maize tissues and over time in response to abscisic acid and drought treatments. CONCLUSIONS: The results presented in this study provide basic information on maize CCCH proteins and form the foundation for future functional studies of these proteins, especially for those members of which may play important roles in response to abiotic stresses.

  10. The core regulatory network of the abscisic acid pathway in banana: genome-wide identification and expression analyses during development, ripening, and abiotic stress.

    Science.gov (United States)

    Hu, Wei; Yan, Yan; Shi, Haitao; Liu, Juhua; Miao, Hongxia; Tie, Weiwei; Ding, Zehong; Ding, XuPo; Wu, Chunlai; Liu, Yang; Wang, Jiashui; Xu, Biyu; Jin, Zhiqiang

    2017-08-29

    Abscisic acid (ABA) signaling plays a crucial role in developmental and environmental adaptation processes of plants. However, the PYL-PP2C-SnRK2 families that function as the core components of ABA signaling are not well understood in banana. In the present study, 24 PYL, 87 PP2C, and 11 SnRK2 genes were identified from banana, which was further supported by evolutionary relationships, conserved motif and gene structure analyses. The comprehensive transcriptomic analyses showed that banana PYL-PP2C-SnRK2 genes are involved in tissue development, fruit development and ripening, and response to abiotic stress in two cultivated varieties. Moreover, comparative expression analyses of PYL-PP2C-SnRK2 genes between BaXi Jiao (BX) and Fen Jiao (FJ) revealed that PYL-PP2C-SnRK2-mediated ABA signaling might positively regulate banana fruit ripening and tolerance to cold, salt, and osmotic stresses. Finally, interaction networks and co-expression assays demonstrated that the core components of ABA signaling were more active in FJ than in BX in response to abiotic stress, further supporting the crucial role of the genes in tolerance to abiotic stress in banana. This study provides new insights into the complicated transcriptional control of PYL-PP2C-SnRK2 genes, improves the understanding of PYL-PP2C-SnRK2-mediated ABA signaling in the regulation of fruit development, ripening, and response to abiotic stress, and identifies some candidate genes for genetic improvement of banana.

  11. Root and leaf abscisic acid concentration impact on gas exchange in tomato (Lycopersicon esculentum Mill plants subjected to partial root-zone drying

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    Maria Valerio

    2017-03-01

    Full Text Available Partial root-zone drying (PRD is a deficit irrigation technique with great potential for water saving. A split-root experiment was conducted on tomato in controlled environment in order to test the response of two long-time storage cultivars to PRD. Ponderosa tomato, a cultivar with yellow fruits, was compared to Giallo tondo di Auletta, a local cultivar from southern Campania (Italy. Plants were subjected to three irrigation treatments: plants receiving an amount of water equivalent to 100% of plant evapotranspiration (V100; plants in which 50% of the amount of water given to V100 was supplied (V50; and plants where one root compartment was irrigated at 50% of water requirements and the other compartment was allowed to dry, and thereafter every side was rewetted alternatively (PRD. The highest levels of leaf abscisic acid (ABA [on average equal to 104 ng g–1 fresh weight FW] were measured in PRD and V50, at 70 days after transplantation. Root ABA concentration in both PRD and V50 reached mean values of 149 ng g–1 FW. There were differences for the irrigation regime in root ABA biosynthesis and accumulation under partial root-zone drying and conventional deficit irrigation (V50. Assimilation rate, stomatal conductance and intercellular CO2 concentration decreased in relation to the irrigation regime by 22, 36 and 12%, respectively, in PRD, V50 and V100 at 50 days after transplantation. Ponderosa variety accumulated 20% more dry matter than Auletta and significant differences were observed in leaf area. In both PRD and V50 of the two varieties, it was possible to save on average 46% of water. Our results indicate that there is still space to optimise the PRD strategy, to further improve the cumulative physiological effects of the root-sourced signaling system.

  12. 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.

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    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.

  13. Local root abscisic acid (ABA) accumulation depends on the spatial distribution of soil moisture in potato: implications for ABA signalling under heterogeneous soil drying.

    Science.gov (United States)

    Puértolas, Jaime; Conesa, María R; Ballester, Carlos; Dodd, Ian C

    2015-04-01

    Patterns of root abscisic acid (ABA) accumulation ([ABA]root), root water potential (Ψroot), and root water uptake (RWU), and their impact on xylem sap ABA concentration ([X-ABA]) were measured under vertical partial root-zone drying (VPRD, upper compartment dry, lower compartment wet) and horizontal partial root-zone drying (HPRD, two lateral compartments: one dry, the other wet) of potato (Solanum tuberosum L.). When water was withheld from the dry compartment for 0-10 d, RWU and Ψroot were similarly lower in the dry compartment when soil volumetric water content dropped below 0.22cm(3) cm(-3) for both spatial distributions of soil moisture. However, [ABA]root increased in response to decreasing Ψroot in the dry compartment only for HPRD, resulting in much higher ABA accumulation than in VPRD. The position of the sampled roots (~4cm closer to the surface in the dry compartment of VPRD than in HPRD) might account for this difference, since older (upper) roots may accumulate less ABA in response to decreased Ψroot than younger (deeper) roots. This would explain differences in root ABA accumulation patterns under vertical and horizontal soil moisture gradients reported in the literature. In our experiment, these differences in root ABA accumulation did not influence [X-ABA], since the RWU fraction (and thus ABA export to shoots) from the dry compartment dramatically decreased simultaneously with any increase in [ABA]root. Thus, HPRD might better trigger a long-distance ABA signal than VPRD under conditions allowing simultaneous high [ABA]root and relatively high RWU fraction. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  14. Suppression Subtractive Hybridization Analysis of Genes Regulated by Application of Exogenous Abscisic Acid in Pepper Plant (Capsicum annuum L. Leaves under Chilling Stress.

    Directory of Open Access Journals (Sweden)

    Wei-Li Guo

    Full Text Available Low temperature is one of the major factors limiting pepper (Capsicum annuum L. production during winter and early spring in non-tropical regions. Application of exogenous abscisic acid (ABA effectively alleviates the symptoms of chilling injury, such as wilting and formation of necrotic lesions on pepper leaves; however, the underlying molecular mechanism is not understood. The aim of this study was to identify genes that are differentially up- or downregulated in ABA-pretreated hot pepper seedlings incubated at 6°C for 48 h, using a suppression subtractive hybridization (SSH method. A total of 235 high-quality ESTs were isolated, clustered and assembled into a collection of 73 unigenes including 18 contigs and 55 singletons. A total of 37 unigenes (50.68% showed similarities to genes with known functions in the non-redundant database; the other 36 unigenes (49.32% showed low similarities or unknown functions. Gene ontology analysis revealed that the 37 unigenes could be classified into nine functional categories. The expression profiles of 18 selected genes were analyzed using quantitative RT-PCR; the expression levels of 10 of these genes were at least two-fold higher in the ABA-pretreated seedlings under chilling stress than water-pretreated (control plants under chilling stress. In contrast, the other eight genes were downregulated in ABA-pretreated seedlings under chilling stress, with expression levels that were one-third or less of the levels observed in control seedlings under chilling stress. These results suggest that ABA can positively and negatively regulate genes in pepper plants under chilling stress.

  15. Dormancy termination of western white pine (Pinus monticola Dougl. Ex D. Don) seeds is associated with changes in abscisic acid metabolism.

    Science.gov (United States)

    Feurtado, J Allan; Ambrose, Stephen J; Cutler, Adrian J; Ross, Andrew R S; Abrams, Suzanne R; Kermode, Allison R

    2004-02-01

    Western white pine (Pinus monticola) seeds exhibit deep dormancy at maturity and seed populations require several months of moist chilling to reach their uppermost germination capacities. Abscisic acid (ABA) and its metabolites, phaseic acid (PA), dihydrophaseic acid (DPA), 7'-hydroxy ABA (7'OH ABA) and ABA-glucose ester (ABA-GE), were quantified in western white pine seeds during dormancy breakage (moist chilling) and germination using an HPLC-tandem mass spectrometry method with multiple reaction monitoring and internal standards incorporating deuterium-labeled analogs. In the seed coat, ABA and metabolite levels were high in dry seeds, but declined precipitously during the pre-moist-chilling water soak to relatively low levels thereafter. In the embryo and megagametophyte, ABA levels decreased significantly during moist chilling, coincident with an increase in the germination capacity of seeds. ABA catabolism occurred via several routes, depending on the stage and the seed tissue. Moist chilling of seeds led to increases in PA and DPA levels in both the embryo and megagametophyte. Within the embryo, 7'OH ABA and ABA-GE also accumulated during moist chilling; however, 7'OH ABA peaked early in germination. Changes in ABA flux, i.e. shifts in the ratio between biosynthesis and catabolism, occurred at three distinct stages during the transition from dormant seed to seedling. During moist chilling, the relative rate of ABA catabolism exceeded ABA biosynthesis. This trend became even more pronounced during germination, and germination was also accompanied by a decrease in the ABA catabolites DPA and PA, presumably as a result of their further metabolism and/or leaching/transport. The transition from germination to post-germinative growth was accompanied by a shift toward ABA biosynthesis. Dormant imbibed seeds, kept in warm moist conditions for 30 days (after an initial 13 days of soaking), maintained high ABA levels, while the amounts of PA, 7'OH ABA, and DPA

  16. Expression analysis of β-glucosidase genes that regulate abscisic acid homeostasis during watermelon (Citrullus lanatus) development and under stress conditions.

    Science.gov (United States)

    Li, Qian; Li, Ping; Sun, Liang; Wang, Yanping; Ji, Kai; Sun, Yufei; Dai, Shengjie; Chen, Pei; Duan, Chaorui; Leng, Ping

    2012-01-01

    The aim of this study was to obtain new insights into the mechanisms that regulate endogenous abscisic acid (ABA) levels by β-glucosidase genes during the development of watermelons (Citrullus lanatus) and under drought stress conditions. In total, five cDNAs from watermelons were cloned by using reverse transcription-PCR (RT-PCR). They included three cDNAs (ClBG1, ClBG2 and ClBG3) homologous to those that encode β-glucosidase l that hydrolyzes the ABA glucose ester (ABA-GE) to release active ABA, ClNCED4, which encodes 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in ABA biosynthesis, and ClCYP707A1, encoding ABA 8'-hydroxylase. A BLAST homology search revealed that the sequences of cDNAs and the deduced amino acids of these genes showed a high degree of homology to comparable molecules of other plant species. During fruit development and ripening, the expressions of ClBG1, ClNCED4 and ClCYP707A1 were relatively low at an early stage, increased rapidly along with fruit ripening, and reached the highest levels at 27 days after full bloom (DAFB) at the harvest stage. This trend was consistent with the accumulation of ABA. The ClBG2 gene on the other hand was highly expressed at 5 DAFB, and then decreased gradually with fruit development. Unlike ClBG1 and ClBG2, the expression of ClBG3 was low at an early stage; its expression peak occurred at 15 DAFB and then declined to the lowest point. When watermelon seedlings were subjected to drought stress, expressions of ClBG1 and ClCYP707A1 were significantly down-regulated, while expressions of ClBG2 and ClNCED4 were up-regulated in the roots, stems and leaves. The expression of ClBG3 was down-regulated in root tissue, but was up-regulated in stems and leaves. In conclusion, endogenous ABA content was modulated by a dynamic balance between biosynthesis and catabolism regulated by ClNCED4, ClCYP707A1 and ClBGs during development and under drought stress condition. It seems likely that β-glucosidase genes are

  17. Age and sex-related changes in cytokinins, auxins and abscisic acid in a centenarian relict herbaceous perennial.

    Science.gov (United States)

    Oñate, Marta; García, Maria B; Munné-Bosch, Sergi

    2012-02-01

    It is still an unsolved question of fundamental biology if, and how, perennial plants senesce. Here, age- and sex-related changes in phytohormones were tested in Borderea pyrenaica, a small dioecious geophyte relict of the Tertiary with one of the longest lifespan ever recorded for any non-clonal herb (more than 300 years). Biomass allocation, together with levels of cytokinins, auxins and absicisic acid, and other indicators of leaf physiology (chlorophylls, lipid peroxidation and F (v)/F (m) ratio) were measured in juvenile and mature plants, including both males and females of three age classes (up to 50 years, 50-100 years, and over 100 years). Plants maintained intact capacity of their vegetative growth and reproductive potential. Cytokinin levels decreased with age, but only in females. Such sex-related differences, however, were not associated with symptoms of physiological deterioration in leaves, but with an increased reproductive effort in females. It is concluded that B. pyrenaica does not show clear signs of senescence at the organism level. Altered cytokinin levels in females were associated with their reproductive effort, rather than to a degenerative process. The alternate use of five meristematic points in the tuber could explain the extraordinary longevity of this species.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Glutathione reductase in leaves of cowpea: cloning of two cDNAs, expression and enzymatic activity under progressive drought stress, desiccation and abscisic acid treatment.

    Science.gov (United States)

    Contour-Ansel, Dominique; Torres-Franklin, Maria Lucia; Cruz DE Carvalho, Maria Helena; D'Arcy-Lameta, Agnès; Zuily-Fodil, Yasmine

    2006-12-01

    Reactive oxygen species are frequently produced when plants are exposed to abiotic stresses. Among the detoxication systems, two enzymes, ascorbate peroxidase and glutathione reductase (GR) play key roles. GR has also a central role in keeping the reduced glutathione pool during stress thus allowing the adjustments on the cellular redox reactions. The aim of this work was to study the variations in cytosolic and dual-targeted GR gene expression in the leaves of cowpea plants submitted to progressive drought, rapid desiccation and application of exogenous abscisic acid (ABA). Two cowpea (Vigna unguiculata) cultivars, one drought-resistant ('EPACE-1'), the other drought-sensitive ('1183') were submitted to progressive drought stress by withholding irrigation. Cut-off leaves were air-dried or treated with exogenous ABA. Two GR cDNAs, one cytosolic, the other dual-targeted to chloroplasts and mitochondria were isolated by PCR and cloned in plasmid vectors. Reverse-transcription PCR was used to study the variations in GR gene expression. Two new cDNAs encoding a putative dual-targeted and a cytosolic GR were cloned and sequenced from leaves of V. unguiculata. Drought stress induced an up-regulation of the expression of the cytosolic GR gene directly related to the intensity of the stress in both cultivars. The expression of dual-targeted GR was up-regulated by the drought treatment in the susceptible cultivar only. Under a fast desiccation, the '1183' cultivar responded later than the 'EPACE-1', although in 'EPACE-1' it was the cytosolic isoform which responded and in '1183' the dual-targeted one. Exogenous ABA enhanced significantly the activity and expression levels of GR in both cultivars after treatment for 24 h. These results demonstrate a noticeable activation in both cultivars of the antioxidant metabolism under a progressive water stress, which involves both GR genes in the case of the susceptible cultivar. Under a fast desiccation, the susceptible cultivar

  20. Gene expression analyses in tomato near isogenic lines provide evidence for ethylene and abscisic acid biosynthesis fine-tuning during arbuscular mycorrhiza development.

    Science.gov (United States)

    Fracetto, Giselle Gomes Monteiro; Peres, Lázaro Eustáquio Pereira; Lambais, Marcio Rodrigues

    2017-07-01

    Plant responses to the environment and microorganisms, including arbuscular mycorrhizal fungi, involve complex hormonal interactions. It is known that abscisic acid (ABA) and ethylene may be involved in the regulation of arbuscular mycorrhiza (AM) and that part of the detrimental effects of ABA deficiency in plants is due to ethylene overproduction. In this study, we aimed to determine whether the low susceptibility to mycorrhizal colonization in ABA-deficient mutants is due to high levels of ethylene and whether AM development is associated with changes in the steady-state levels of transcripts of genes involved in the biosynthesis of ethylene and ABA. For that, tomato (Solanum lycopersicum) ethylene overproducer epinastic (epi) mutant and the ABA-deficient notabilis (not) and sitiens (sit) mutants, in the same Micro-Tom (MT) genetic background, were inoculated with Rhizophagus clarus, and treated with the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG). The development of AM, as well as the steady-state levels of transcripts involved in ethylene (LeACS2, LeACO1 and LeACO4) and ABA (LeNCED) biosynthesis, was determined. The intraradical colonization in epi, not and sit mutants was significantly reduced compared to MT. The epi mutant completely restored the mycorrhizal colonization to the levels of MT with the application of 10 µM of AVG, probably due to the inhibition of the ACC synthase gene expression. The steady-state levels of LeACS2 and LeACO4 transcripts were induced in mycorrhizal roots of MT, whereas the steady-state levels of LeACO1 and LeACO4 transcripts were significantly induced in sit, and the steady-state levels of LeNCED transcripts were significantly induced in all genotypes and in mycorrhizal roots of epi mutants treated with AVG. The reduced mycorrhizal colonization in sit mutants seems not to be limited by ethylene production via ACC oxidase regulation. Both ethylene overproduction and ABA deficiency impaired AM fungal

  1. Transcriptional regulation of abscisic acid signal core components during cucumber seed germination and under Cu²⁺, Zn²⁺, NaCl and simulated acid rain stresses.

    Science.gov (United States)

    Wang, Yanping; Wang, Ya; Kai, Wenbin; Zhao, Bo; Chen, Pei; Sun, Liang; Ji, Kai; Li, Qian; Dai, Shengjie; Sun, Yufei; Wang, Yidong; Pei, Yuelin; Leng, Ping

    2014-03-01

    Abscisic acid (ABA) is an important phytohormone that regulates lots of physiological and biochemical processes in plant life cycle, especially in seed germination and stress responses. For exploring the transcriptional regulation of ABA signal transduction during cucumber (Cucumis sativus L.) seed germination and under Cu(2+), Zn(2+), NaCl and simulated acid rain stresses, nine CsPYLs, three group A CsPP2Cs and two subclass III CsSnRK2s were identified from cucumber genome, which respectively showed high sequence similarities and highly conserved domains with homologous genes in Arabidopsis. Based on Real-time PCR analysis, most of the tested genes' expression decreased during cucumber seed germination, which was in accordance with the ABA level variation. In addition, according to the absolute expression, CsPYL1, CsPYL3, CsPP2C5, CsABI1, CsSnRK2.3 and CsSnRK2.4 were highly expressed, indicating that they may play more important roles in ABA signaling during cucumber seed germination. Moreover, most of these highly expressed genes, except CsPYL3, were up-regulated by ABA treatment. Meanwhile, most of the tested genes' expression dramatically changed at the initial water uptake phase, indicating that this period may be critical in the regulation of ABA on seed germination. Under Cu(2+), Zn(2+), NaCl and simulated acid rain stresses, cucumber seed germination percentage decreased and ABA content increased. Meanwhile, the expression of ABA signal transduction core components genes showed specific response to a particular stress and was not always consist with ABA variation. Generally, the expression of CsPYL1, CsPYL3, CsABI1, CsSnRK2.3 and CsSnRK2.4 was sensitive to 120 mM NaCl and 0.5 mM Cu(2+) treatments. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  2. Electronic coupling through natural amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Berstis, Laura; Beckham, Gregg T., E-mail: michael.crowley@nrel.gov, E-mail: gregg.beckham@nrel.gov; Crowley, Michael F., E-mail: michael.crowley@nrel.gov, E-mail: gregg.beckham@nrel.gov [National Renewable Energy Laboratory, National Bioenergy Center, 15013 Denver West Pkwy, Golden, Colorado 80401 (United States)

    2015-12-14

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green’s function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design.

  3. HAB1–SWI3B Interaction Reveals a Link between Abscisic Acid Signaling and Putative SWI/SNF Chromatin-Remodeling Complexes in Arabidopsis[C][W

    Science.gov (United States)

    Saez, Angela; Rodrigues, Americo; Santiago, Julia; Rubio, Silvia; Rodriguez, Pedro L.

    2008-01-01

    Abscisic acid (ABA) has an important role for plant growth, development, and stress adaptation. HYPERSENSITIVE TO ABA1 (HAB1) is a protein phosphatase type 2C that plays a key role as a negative regulator of ABA signaling; however, the molecular details of HAB1 action in this process are not known. A two-hybrid screen revealed that SWI3B, an Arabidopsis thaliana homolog of the yeast SWI3 subunit of SWI/SNF chromatin-remodeling complexes, is a prevalent interacting partner of HAB1. The interaction mapped to the N-terminal half of SWI3B and required an intact protein phosphatase catalytic domain. Bimolecular fluorescence complementation and coimmunoprecipitation assays confirmed the interaction of HAB1 and SWI3B in the nucleus of plant cells. swi3b mutants showed a reduced sensitivity to ABA-mediated inhibition of seed germination and growth and reduced expression of the ABA-responsive genes RAB18 and RD29B. Chromatin immunoprecipitation experiments showed that the presence of HAB1 in the vicinity of RD29B and RAB18 promoters was abolished by ABA, which suggests a direct involvement of HAB1 in the regulation of ABA-induced transcription. Additionally, our results uncover SWI3B as a novel positive regulator of ABA signaling and suggest that HAB1 modulates ABA response through the regulation of a putative SWI/SNF chromatin-remodeling complex. PMID:19033529

  4. Damage to the plasmalemma, chloroplasts and photosystem II after water shortage and high-temperature stress in two lines of maize which differ in endogenous levels of abscisic acid and drought resistance

    Energy Technology Data Exchange (ETDEWEB)

    Ristic, Z.; Cass, D.D. (Univ. of Alberta, Edmonton (Canada))

    1991-05-01

    This study examines damage to the plasmalemma, chloroplasts and photosystem II (PS II), and the rate of CO{sub 2} fixation after exposure to 7-d water shortage followed by 6-h (WTS-6) or 24-h (WTS-24) high temperature (45C) stress in the high-level. Abscisic acid (ABA) drought-resistant (DR) line of maize ZPBL 1304 and the low-level ABA drought-sensitive line ZPL 389. Seven-day water shortage followed by 6-h high-temperature stress slightly damaged PS II in the DR line ZPBL 1304. The DS line ZPL 389 was affected by WTS-6 to a great extent; however, the stress-caused damage to this line was reversible. Exposure to WTS-24 caused reversible damage to the plasmalemma, chloroplasts and PS II in DR line. The DS line was not capable of withstanding severe stress conditions; WTS-24 killed almost all the plants. The results on the rate of CO{sub 2} fixation were in agreement with those on the damage to the plasmalemma, chloroplasts and PS II. Considerable drought and heat resistance was apparent in the line (ZPBL 1304) which synthesizes a unique band of heat-shock protein(s) of 45 KDa. In conclusion, the high-level ABA DR line ZPBL 1304 showed much greater capability of withstanding WTS than the low-level ABA DS line ZPL 389.

  5. Resistance to Botrytis cinerea in sitiens, an Abscisic Acid-Deficient Tomato Mutant, Involves Timely Production of Hydrogen Peroxide and Cell Wall Modifications in the Epidermis1[C][W][OA

    Science.gov (United States)

    Asselbergh, Bob; Curvers, Katrien; França, Soraya C.; Audenaert, Kris; Vuylsteke, Marnik; Van Breusegem, Frank; Höfte, Monica

    2007-01-01

    Plant defense mechanisms against necrotrophic pathogens, such as Botrytis cinerea, are considered to be complex and to differ from those that are effective against biotrophs. In the abscisic acid-deficient sitiens tomato (Solanum lycopersicum) mutant, which is highly resistant to B. cinerea, accumulation of hydrogen peroxide (H2O2) was earlier and stronger than in the susceptible wild type at the site of infection. In sitiens, H2O2 accumulation was observed from 4 h postinoculation (hpi), specifically in the leaf epidermal cell walls, where it caused modification by protein cross-linking and incorporation of phenolic compounds. In wild-type tomato plants, H2O2 started to accumulate 24 hpi in the mesophyll layer and was associated with spreading cell death. Transcript-profiling analysis using TOM1 microarrays revealed that defense-related transcript accumulation prior to infection was higher in sitiens than in wild type. Moreover, further elevation of sitiens defense gene expression was stronger than in wild type 8 hpi both in number of genes and in their expression levels and confirmed a role for cell wall modification in the resistant reaction. Although, in general, plant defense-related reactive oxygen species formation facilitates necrotrophic colonization, these data indicate that timely hyperinduction of H2O2-dependent defenses in the epidermal cell wall can effectively block early development of B. cinerea. PMID:17573540

  6. Over-expression of LeNCED1 in tomato (Solanum lycopersicum L.) with the rbcS3C promoter allows recovery of lines that accumulate very high levels of abscisic acid and exhibit severe phenotypes.

    Science.gov (United States)

    Tung, Swee Ang; Smeeton, Rachel; White, Charlotte A; Black, Colin R; Taylor, Ian B; Hilton, Howard W; Thompson, Andrew J

    2008-07-01

    Previous work where 9-cis-epoxycarotenoid dioxygenase (NCED) was over-expressed using the constitutive Gelvin Superpromoter resulted in mild increases in abscisic acid (ABA) accumulation, accompanied by stomatal closure and increased water-use efficiency (WUE), but with apparently little impact on long-term biomass production. However, one of the negative effects of the over-expression of NCED using constitutive promoters in tomato was increased seed dormancy. Here we report the use of the rbcS3C promoter, from a gene encoding the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), to drive LeNCED1 transgene expression in tomato in a light-responsive and circadian manner. In comparison to the constitutive promoter, the rbcS3C promoter allowed the generation of transgenic plants with much higher levels of ABA accumulation in leaves and sap, but the effect on seed dormancy was diminished. These plants displayed the expected reductions in stomatal conductance and CO(2) assimilation, but they also exhibited a severe set of symptoms that included perturbed cotyledon release from the testa, increased photobleaching in young seedlings, substantially reduced chlorophyll and carotenoid content, interveinal leaf flooding, and greatly reduced growth. These symptoms illustrate adverse consequences of long-term, very high ABA accumulation. Only more moderate increases in ABA biosynthesis are likely to be useful in the context of agriculture. Implications are discussed for the design of transgenic 'high ABA' plants that exhibit increased WUE but have minimal negative phenotypic effects.

  7. 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[CC-BY

    Science.gov (United States)

    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

  8. The Arabidopsis adaptor protein AP-3µ interacts with the G-protein β subunit AGB1 and is involved in abscisic acid regulation of germination and post-germination development

    Science.gov (United States)

    Tsugama, Daisuke; Takano, Tetsuo

    2013-01-01

    Heterotrimeric G-proteins (G-proteins) have been implicated in ubiquitous signalling mechanisms in eukaryotes. In plants, G-proteins modulate hormonal and stress responses and regulate diverse developmental processes. However, the molecular mechanisms of their functions are largely unknown. A yeast two-hybrid screen was performed to identify interacting partners of the Arabidopsis G-protein β subunit AGB1. One of the identified AGB1-interacting proteins is the Arabidopsis adaptor protein AP-3µ. The interaction between AGB1 and AP-3µ was confirmed by an in vitro pull-down assay and bimolecular fluorescence complementation assay. Two ap-3µ T-DNA insertional mutants were found to be hyposensitive to abscisic acid (ABA) during germination and post-germination growth, whereas agb1 mutants were hypersensitive to ABA. During seed germination, agb1/ap-3µ double mutants were more sensitive to ABA than the wild type but less sensitive than agb1 mutants. However, in post-germination growth, the double mutants were as sensitive to ABA as agb1 mutants. These data suggest that AP-3µ positively regulates the ABA responses independently of AGB1 in seed germination, while AP-3µ does require AGB1 to regulate ABA responses during post-germination growth. PMID:24098050

  9. Natural modifiers of seed longevity in the Arabidopsis mutants abscisic acid insensitive3-5 (abi3-5) and leafy cotyledon1-3 (lec1-3).

    Science.gov (United States)

    Sugliani, Matteo; Rajjou, Loïc; Clerkx, Emile J M; Koornneef, Maarten; Soppe, Wim J J

    2009-12-01

    *Seed longevity is an important trait in many crops and is essential for the success of most land plant species. Current knowledge of its molecular regulation is limited. The Arabidopsis mutants abscisic acid insensitive3-5 (abi3-5) and leafy cotyledon1-3 (lec1-3) have impaired seed maturation and quickly lose seed viability. abi3-5 and lec1-3 were used as sensitized genetic backgrounds for the study of seed longevity. *We exploited the natural variation of Arabidopsis to create introgression lines from the Seis am Schlern and Shahdara accessions in, respectively, the abi3-5 and lec1-3 backgrounds. These lines carry natural modifiers of the abi3 and lec1 phenotypes. Longevity tests and a proteomic analysis were conducted to describe the seed physiology of each line. *The modifier lines showed improved seed longevity. The Shahdara modifiers can partially re-establish the seed developmental programs controlled by LEC1 and restore the accumulation of seed storage proteins that are reduced in abi3-5 and lec1-3. *The isolation and characterization of natural modifiers of the seed maturation mutants abi3-5 and lec1-3, and the analysis of their seed proteomes, advance our current understanding of seed longevity.

  10. Virus-induced down-regulation of GmERA1A and GmERA1B genes enhances the stomatal response to abscisic acid and drought resistance in soybean.

    Directory of Open Access Journals (Sweden)

    Takuya Ogata

    Full Text Available Drought is a major threat to global soybean production. The limited transformation potential and polyploid nature of soybean have hindered functional analysis of soybean genes. Previous research has implicated farnesylation in the plant's response to abscisic acid (ABA and drought tolerance. We therefore used virus-induced gene silencing (VIGS to evaluate farnesyltransferase genes, GmERA1A and GmERA1B (Glycine max Enhanced Response to ABA1-A and -B, as potential targets for increasing drought resistance in soybean. Apple latent spherical virus (ALSV-mediated GmERA1-down-regulated soybean leaves displayed an enhanced stomatal response to ABA and reduced water loss and wilting under dehydration conditions, suggesting that GmERA1A and GmERA1B negatively regulate ABA signaling in soybean guard cells. The findings provide evidence that the ALSV-VIGS system, which bypasses the need to generate transgenic plants, is a useful tool for analyzing gene function using only a single down-regulated leaf. Thus, the ALSV-VIGS system could constitute part of a next-generation molecular breeding pipeline to accelerate drought resistance breeding in soybean.

  11. Negative Regulation of Abscisic Acid Signaling by the Fagus sylvatica FsPP2C1 Plays A Role in Seed Dormancy Regulation and Promotion of Seed Germination1

    Science.gov (United States)

    González-García, Mary Paz; Rodríguez, Dolores; Nicolás, Carlos; Rodríguez, Pedro Luis; Nicolás, Gregorio; Lorenzo, Oscar

    2003-01-01

    FsPP2C1 was previously isolated from beech (Fagus sylvatica) seeds as a functional protein phosphatase type-2C (PP2C) with all the conserved features of these enzymes and high homology to ABI1, ABI2, and PP2CA, PP2Cs identified as negative regulators of ABA signaling. The expression of FsPP2C1 was induced upon abscisic acid (ABA) treatment and was also up-regulated during early weeks of stratification. Furthermore, this gene was specifically expressed in ABA-treated seeds and was hardly detectable in vegetative tissues. In this report, to provide genetic evidence on FsPP2C1 function in seed dormancy and germination, we used an overexpression approach in Arabidopsis because transgenic work is not feasible in beech. Constitutive expression of FsPP2C1 under the cauliflower mosaic virus 35S promoter confers ABA insensitivity in Arabidopsis seeds and, consequently, a reduced degree of seed dormancy. Additionally, transgenic 35S:FsPP2C1 plants are able to germinate under unfavorable conditions, as inhibitory concentrations of mannitol, NaCl, or paclobutrazol. In vegetative tissues, Arabidopsis FsPP2C1 transgenic plants show ABA-resistant early root growth and diminished induction of the ABA-response genes RAB18 and KIN2, but no effect on stomatal closure regulation. Seed and vegetative phenotypes of Arabidopsis 35S:FsPP2C1 plants suggest that FsPP2C1 negatively regulates ABA signaling. The ABA inducibility of FsPP2C1 expression, together with the transcript accumulation mainly in seeds, suggest that it could play an important role modulating ABA signaling in beechnuts through a negative feedback loop. Finally, we suggest that negative regulation of ABA signaling by FsPP2C1 is a factor contributing to promote the transition from seed dormancy to germination during early weeks of stratification. PMID:12970481

  12. Importance of Abscisic Acid (ABA in the In Vitro Conservation of Cassava (Manihot esculenta Crantz Importancia del Ácido Abscísico (ABA en la Conservación In Vitro de la Yuca (Manihot esculenta Crantz

    Directory of Open Access Journals (Sweden)

    L. Pedro Barrueto Cid

    2008-09-01

    Full Text Available The conventional technology for in vitro plant conservation for cassava (Manihot esculenta Crantz germplasm collections is laborious due to the need for several sub-culturing procedures per year. This practice implies high costs for medium preparation, tissue culture tubes, time-consuming labor, risks of contamination, mislabeling of accession, and the need for large growth chambers. We have developed a new procedure using in vitro cultivated nodal axillary buds treated with different abscisic acid (ABA concentrations to reduce the time for recycling transplants cultivated in a SP basic nutritive medium. Nodal explants were stored for three months with ABA. Plants were obtained after nodal axillary buds were placed in SP medium without ABA. Results indicated that 20 and 30 mM ABA induced bud dormancy and delayed sprouting without affecting subsequent growth of plants after treatment.La tecnología usual para conservación in vitro de colecciones de germoplasma de yuca (Manihotesculenta Crantz es corrientemente laboriosa y emplea varias transferencias por año. Este procedimiento envuelve altos costos en preparación de medios, consumo de tiempo, riesgos de manipulación y necesidad de mucho espacio para la mantención de colecciones en cámaras de cultivos. Se desarrolló un nuevo procedimiento usando yemas axilares nodales cultivadas in vitro con diferentes concentraciones de ácido abscísico (ABA, con el objetivo de reducir los ciclos de transferencia de los cultivos mantenidos en un medio nutritivo básico tal como el SP. Los segmentos nodales fueron almacenados por tres meses en presencia de ABA. Las plantas fueron obtenidas después que los segmentos nodales fueron transferidos al medio SP sin ABA. Los resultados indican que 20 y 30 mM de ABA indujeron una completa dormancia de yemas, sin afectar el desarrollo posterior de las yemas nodales y su consecuente conversión en planta.

  13. Enhanced Abscisic Acid-Mediated Responses in nia1nia2noa1-2 Triple Mutant Impaired in NIA/NR- and AtNOA1-Dependent Nitric Oxide Biosynthesis in Arabidopsis1[W

    Science.gov (United States)

    Lozano-Juste, Jorge; León, José

    2010-01-01

    Nitric oxide (NO) regulates a wide range of plant processes from development to environmental adaptation. Despite its reported regulatory functions, it remains unclear how NO is synthesized in plants. We have generated a triple nia1nia2noa1-2 mutant that is impaired in nitrate reductase (NIA/NR)- and Nitric Oxide-Associated1 (AtNOA1)-mediated NO biosynthetic pathways. NO content in roots of nia1nia2 and noa1-2 plants was lower than in wild-type plants and below the detection limit in nia1nia2noa1-2 plants. NIA/NR- and AtNOA1-mediated biosynthesis of NO were thus active and responsible for most of the NO production in Arabidopsis (Arabidopsis thaliana). The nia1nia2noa1-2 plants displayed reduced size, fertility, and seed germination potential but increased dormancy and resistance to water deficit. The increasing deficiency in NO of nia1nia2, noa1-2, and nia1nia2noa1-2 plants correlated with increased seed dormancy, hypersensitivity to abscisic acid (ABA) in seed germination and establishment, as well as dehydration resistance. In nia1nia2noa1-2 plants, enhanced drought tolerance was due to a very efficient stomata closure and inhibition of opening by ABA, thus uncoupling NO from ABA-triggered responses in NO-deficient guard cells. The NO-deficient mutants in NIA/NR- and AtNOA1-mediated pathways in combination with the triple mutant will be useful tools to functionally characterize the role of NO and the contribution of both biosynthetic pathways in regulating plant development and defense. PMID:20007448

  14. Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid

    Directory of Open Access Journals (Sweden)

    Tareq Irshaidat

    2014-01-01

    Full Text Available On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput. 2012, 8, 2293 illustrated that beryllium ions are capable of significantly modulating (changing the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+, AlF2(1+, AlF2+, and Al3+ were investigated. Several aspects were addressed: natural bond orbitals, including second order perturbation analysis of intra-molecular charge delocalization and the natural population analysis atomic charges; molecular geometries; selected infrared stretching frequencies (C-N, C-O, and N-H, and selected ¹H-NMR chemical shifts. The data illustrate that this interaction can weaken the H-O bond and goes beyond strengthening the intra-molecular hydrogen bond (N...H-O to cause a spontaneous transfer of the proton to the nitrogen atom in five cases generating zwitterion structures. Many new features are observed. Most importantly, the zwitterion structures include a stabilizing hydrogen bond (N-H...O that varies in relative strength according to the Lewis acid. These findings explain the experimental observations of α-amino acids (for example: J. Am. Chem. Soc. 2001, 123, 3577 and are the first reported fundamental electronic structure characterization of β-amino acids in zwitterion form.

  15. Development and Validation of a Reversed-Phase Liquid Chromatography Method for the Simultaneous Determination of Indole-3-Acetic Acid, Indole-3-Pyruvic Acid, and Abscisic Acid in Barley (Hordeum vulgare L.

    Directory of Open Access Journals (Sweden)

    Ilva Nakurte

    2012-01-01

     mm I.D with a mobile phase composed of methanol and 1% acetic acid (60 : 40 v/v in isocratic mode at a flow rate of 1 ml min-1. The detection was monitored at 270 nm (ABA and at 282 nm (Ex and 360 nm (Em (IAA, IPA. The developed method was validated in terms of accuracy, precision, linearity, limit of detection, limit of quantification, and robustness. The determined validation parameters are in the commonly acceptable ranges for that kind of analysis.

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

    Directory of Open Access Journals (Sweden)

    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

  17. Electronic-state control of amino acids on semiconductor surfaces

    International Nuclear Information System (INIS)

    Oda, Masato; Nakayama, Takashi

    2005-01-01

    Electronic structures of amino acids on the Si(1 1 1) surfaces are investigated by using ab initio Hartree-Fock calculations. It is shown that among various polar amino acids, a histidine is the only one that can be positively ionized when hole carriers are supplied in the Si substrate, by transferring the hole charge from Si substrate to an amino acid. This result indicates that the ionization of a histidine, which will activate the protein functions, can be controlled electrically by producing amino acid/Si junctions

  18. Detecting Electron Transport of Amino Acids by Using Conductance Measurement

    Directory of Open Access Journals (Sweden)

    Wei-Qiong Li

    2017-04-01

    Full Text Available The single molecular conductance of amino acids was measured by a scanning tunneling microscope (STM break junction. Conductance measurement of alanine gives out two conductance values at 10−1.85 G0 (1095 nS and 10−3.7 G0 (15.5 nS, while similar conductance values are also observed for aspartic acid and glutamic acid, which have one more carboxylic acid group compared with alanine. This may show that the backbone of NH2–C–COOH is the primary means of electron transport in the molecular junction of aspartic acid and glutamic acid. However, NH2–C–COOH is not the primary means of electron transport in the methionine junction, which may be caused by the strong interaction of the Au–SMe (methyl sulfide bond for the methionine junction. The current work reveals the important role of the anchoring group in the electron transport in different amino acids junctions.

  19. Electron-induced chemistry in microhydrated sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    J. Lengyel

    2017-11-01

    Full Text Available We investigate the mixed sulfuric acid–water clusters in a molecular beam experiment with electron attachment and negative ion mass spectrometry and complement the experiment by density functional theory (DFT calculations. The microhydration of (H2SO4m(H2On clusters is controlled by the expansion conditions, and the electron attachment yields the main cluster ion series (H2SO4m(H2OnHSO4− and (H2OnH2SO4−. The mass spectra provide an experimental evidence for the onset of the ionic dissociation of sulfuric acid and ion-pair (HSO4−  ⋅  ⋅  ⋅  H3O+ formation in the neutral H2SO4(H2On clusters with n ≥ 5 water molecules, in excellent agreement with the theoretical predictions. In the clusters with two sulfuric acid molecules (H2SO42(H2On this process starts as early as n ≥ 2 water molecules. The (H2SO4m(H2OnHSO4− clusters are formed after the dissociative electron attachment to the clusters containing the (HSO4−  ⋅  ⋅  ⋅  H3O+ ion-pair structure, which leads to the electron recombination with the H3O+ moiety generating H2O molecule and the H-atom dissociation from the cluster. The (H2OnH2SO4− cluster ions point to an efficient caging of the H atom by the surrounding water molecules. The electron-energy dependencies exhibit an efficient electron attachment at low electron energies below 3 eV, and no resonances above this energy, for all the measured mass peaks. This shows that in the atmospheric chemistry only the low-energy electrons can be efficiently captured by the sulfuric acid–water clusters and converted into the negative ions. Possible atmospheric consequences of the acidic dissociation in the clusters and the electron attachment to the sulfuric acid–water aerosols are discussed.

  20. Wearable salivary uric acid mouthguard biosensor with integrated wireless electronics.

    Science.gov (United States)

    Kim, Jayoung; Imani, Somayeh; de Araujo, William R; Warchall, Julian; Valdés-Ramírez, Gabriela; Paixão, Thiago R L C; Mercier, Patrick P; Wang, Joseph

    2015-12-15

    This article demonstrates an instrumented mouthguard capable of non-invasively monitoring salivary uric acid (SUA) levels. The enzyme (uricase)-modified screen printed electrode system has been integrated onto a mouthguard platform along with anatomically-miniaturized instrumentation electronics featuring a potentiostat, microcontroller, and a Bluetooth Low Energy (BLE) transceiver. Unlike RFID-based biosensing systems, which require large proximal power sources, the developed platform enables real-time wireless transmission of the sensed information to standard smartphones, laptops, and other consumer electronics for on-demand processing, diagnostics, or storage. The mouthguard biosensor system offers high sensitivity, selectivity, and stability towards uric acid detection in human saliva, covering the concentration ranges for both healthy people and hyperuricemia patients. The new wireless mouthguard biosensor system is able to monitor SUA level in real-time and continuous fashion, and can be readily expanded to an array of sensors for different analytes to enable an attractive wearable monitoring system for diverse health and fitness applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Modeling molecular acidity with electronic properties and Hammett constants for substituted benzoic acids.

    Science.gov (United States)

    Huang, Ying; Liu, Lianghong; Liu, Wanhui; Liu, Shaogang; Liu, Shubin

    2011-12-29

    Molecular acidity is an important physiochemical property essential in many fields of molecular studies, but an efficient and reliable computational approach to make accurate predictions is still missing. In this work, based on our previous studies to use gas phase electronic properties such as molecular electrostatic potential and valence natural atomic orbitals of the acidic atom and leaving proton, we demonstrate here that different approaches can be employed to tackle this problem. To that end, we employ 196 singly, doubly, and triply substituted benzoic acids for the study. We show that two different approaches are possible, one focusing on the carboxyl group through its localized electronic properties and the other on the substituting groups via Hammett constants and their additivity rule. Our present results clearly exhibit that with the linear models built from the singly substituted species, one can accurately predict the pK(a) values for the doubly and triply substituted species with both of these two approaches. The predictions from these approaches are consistent with each other and agree well with the experimental data. These intrinsically different approaches are the two manifestations of the same molecular acidity property, both valid and complementary to each other. © 2011 American Chemical Society

  2. Electron ionization and dissociation of aliphatic amino acids

    Science.gov (United States)

    Papp, P.; Shchukin, P.; Kočíšek, J.; Matejčík, Š.

    2012-09-01

    We present experimental and theoretical study of electron ionization and dissociative ionization to the gas phase amino acids valine, leucine, and isoleucine. A crossed electron/molecular beams technique equipped with quadrupole mass analyzer has been applied to measure mass spectra and ion efficiency curves for formation of particular ions. From experimental data the ionization energies of the molecules and the appearance energies of the fragment ions were determined. Ab initio calculations (Density Functional Theory and G3MP2 methods) were performed in order to calculate the fragmentation paths and interpret the experimental data. The experimental ionization energies of parent molecules [P]+ 8.91 ± 0.05, 8.85 ± 0.05, and 8.79 ± 0.05 eV and G3MP2 ionization energies (adiabatic) of 8.89, 8.88, and 8.81 eV were determined for valine, leucine, and isoleucine, respectively, as well as the experimental and theoretical threshold energies for dissociative ionization channels. The comparison of experimental data with calculations resulted in identification of the ions as well as the neutral fragments formed in the dissociative reactions. Around 15 mass/charge ratio fragments were identified from the mass spectra by comparison of experimental appearance energies with calculated reaction enthalpies for particular dissociative reactions.

  3. Electron donating and acid-base properties of cerium oxide and its mixed oxides with alumina

    International Nuclear Information System (INIS)

    Sugunan, S.; Jalaja, J.M.

    1994-01-01

    The electron donating properties of cerium oxide activated at 300, 500 and 800 degC and of its mixed oxides with alumina were examined based on the adsorption of electron acceptors exhibiting different electron affinities. The surface acidity/basicity of the oxides was determined by titrimetry; the H 0,max values are given. The limit of electron transfer from the oxide surface lies within the region of 1.77 and 2.40 eV in terms of the electron affinity of the electron acceptor. Cerium oxide promotes the electron donor nature of alumina while leaving the limit of electron transfer unchanged. 2 tabs., 4 figs., 13 refs

  4. Electron transport chains of lactic acid bacteria - walking on crutches is part of their lifestyle

    Science.gov (United States)

    Brooijmans, Rob; Hugenholtz, Jeroen

    2009-01-01

    A variety of lactic acid bacteria contain rudimentary electron transport chains that can be reconstituted by the addition of heme and menaquinone to the growth medium. These activated electron transport chains lead to higher biomass production and increased robustness, which is beneficial for industrial applications, but a major concern when dealing with pathogenic lactic acid bacteria. PMID:20948651

  5. Metabolism of Fructophilic Lactic Acid Bacteria Isolated from the Apis mellifera L. Bee Gut: Phenolic Acids as External Electron Acceptors

    Science.gov (United States)

    Filannino, Pasquale; Addante, Rocco; Pontonio, Erica; Gobbetti, Marco

    2016-01-01

    ABSTRACT Fructophilic lactic acid bacteria (FLAB) are strongly associated with the gastrointestinal tracts (GITs) of Apis mellifera L. worker bees due to the consumption of fructose as a major carbohydrate. Seventy-seven presumptive lactic acid bacteria (LAB) were isolated from GITs of healthy A. mellifera L. adults, which were collected from 5 different geographical locations of the Apulia region of Italy. Almost all of the isolates showed fructophilic tendencies: these isolates were identified as Lactobacillus kunkeei (69%) or Fructobacillus fructosus (31%). A high-throughput phenotypic microarray targeting 190 carbon sources was used to determine that 83 compounds were differentially consumed. Phenotyping grouped the strains into two clusters, reflecting growth performance. The utilization of phenolic acids, such as p-coumaric, caffeic, syringic, or gallic acids, as electron acceptors was investigated in fructose-based medium. Almost all FLAB strains showed tolerance to high phenolic acid concentrations. p-Coumaric acid and caffeic acid were consumed by all FLAB strains through reductases or decarboxylases. Syringic and gallic acids were partially metabolized. The data collected suggest that FLAB require external electron acceptors to regenerate NADH. The use of phenolic acids as external electron acceptors by the 4 FLAB showing the highest phenolic acid reductase activity was investigated in glucose-based medium supplemented with p-coumaric acid. Metabolic responses observed through a phenotypic microarray suggested that FLAB may use p-coumaric acid as an external electron acceptor, enhancing glucose dissimilation but less efficiently than other external acceptors such as fructose or pyruvic acid. IMPORTANCE Fructophilic lactic acid bacteria (FLAB) remain to be fully explored. This study intends to link unique biochemical features of FLAB with their habitat. The quite unique FLAB phenome within the group lactic acid bacteria (LAB) may have practical relevance

  6. Hydroxycinnamic acids used as external acceptors of electrons: an energetic advantage for strictly heterofermentative lactic acid bacteria.

    Science.gov (United States)

    Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria; Di Cagno, Raffaella

    2014-12-01

    The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD(+)/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD(+)/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  7. Electron Transfer Studies of Ruthenium(II) Complexes with Biologically Important Phenolic Acids and Tyrosine.

    Science.gov (United States)

    Rajeswari, Angusamy; Ramdass, Arumugam; Muthu Mareeswaran, Paulpandian; Rajagopal, Seenivasan

    2016-03-01

    The ruthenium(II) complexes having 2,2'-bipyridine and phenanthroline derivatives are synthesized and characterized. The photophysical properties of these complexes at pH 12.5 are studied. The electron transfer reaction of biologically important phenolic acids and tyrosine are studied using absorption, emission and transient absorption spectral techniques. Semiclassical theory is applied to calculate the rate of electron transfer between ruthenium(II) complexes and biologically important phenolic acids.

  8. UPS and DFT investigation of the electronic structure of gas-phase trimesic acid

    Energy Technology Data Exchange (ETDEWEB)

    Reisberg, L., E-mail: rebban@ut.ee [Institute of Physics, University of Tartu, W. Oswaldi 1, EE-50411 Tartu (Estonia); Pärna, R. [Institute of Physics, University of Tartu, W. Oswaldi 1, EE-50411 Tartu (Estonia); MAX IV Laboratory, Lund University, Fotongatan 2, 225 94 Lund (Sweden); Kikas, A.; Kuusik, I.; Kisand, V. [Institute of Physics, University of Tartu, W. Oswaldi 1, EE-50411 Tartu (Estonia); Hirsimäki, M.; Valden, M. [Surface Science Laboratory, Optoelectronics Research Centre, Tampere University of Technology, FIN-33101 Tampere (Finland); Nõmmiste, E. [Institute of Physics, University of Tartu, W. Oswaldi 1, EE-50411 Tartu (Estonia)

    2016-11-15

    Highlights: • In the current study outer valence band electronic structure of benzene-1,3,5-tricarboxylic acid was interpreted. • Experimental and calculated trimesic acid (TMA) spectrum were compared to ones of benzene and benzoic acid. • It is shown that similarities between MO energies and shapes for benzene and TMA exists. • Addition of carboxyl groups to the benzene ring clearly correlates with increasing binding energy of HOMO. - Abstract: Benzene-1,3,5-tricarboxylic acid (trimesic acid, TMA) molecules in gas-phase have been investigated by using valence band photoemission. The photoelectron spectrum in the binding energy region from 9 to 22 eV is interpreted by using density functional theory calculations. The electronic structure of TMA is compared with benzene and benzoic acid in order to demonstrate changes in molecular orbital energies induced by addition of carboxyl groups to benzene ring.

  9. Alcohol production through volatile fatty acids reduction with hydrogen as electron donor by mixed cultures

    NARCIS (Netherlands)

    Steinbusch, K.J.J.; Hamelers, H.V.M.; Buisman, C.J.N.

    2008-01-01

    In this research we demonstrated a new method to produce alcohols. It was experimentally feasible to produce ethanol, propanol and butanol from solely volatile fatty acids (VFAs) with hydrogen as electron donor. In batch tests, VFAs such as acetic, propionic and butyric acids were reduced by mixed

  10. Effect of activated charcoal, abscisic acid and polyethylene glycol on ...

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... Regeneration in the genus Aesculus via androgenesis. *Corresponding ... Regeneration of this species via androgenesis provides a means of ..... concentration, polyethylene glycol and activated charcoal on maturation and regeneration of Abies cephalonica somatic embryos. Plant Cell Tiss. Organ Cult.

  11. Perioxidases play important roles in abscisic acid (ABA)-simulating ...

    African Journals Online (AJOL)

    Leaf photosynthetic activity limited by summer heat stress represents large constraint to production process of fruit trees. To cope with this problem, we tested photosystem II (PS II) thermostability in clonal apple tree rootstocks with different growth intensity - semi-vigorous-MM106 and dwarfing-J-TE-F experiencing summer ...

  12. Effect of activated charcoal, abscisic acid and polyethylene glycol on ...

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... Generation of horse chestnut somatic embryos is commonly achieved by transferring embryo- genic tissue onto an ABA, PEG and manitol-containing maturation media (Capuana and Deberg, 1997). Activated charcoal is commonly used in tissue culture media to darken the immediate media surroundings ...

  13. Interactions between ethylene, abscisic acid and cytokinin during ...

    Indian Academy of Sciences (India)

    Santner et al. 2009). Interactions ... Arabidopsis seeds of ecotype Columbia germinate within two days following cold imbibition and transfer to ... ETR1 encodes the ethylene receptor whereas EIN2 encodes a large protein with transmembrane ...

  14. Interactions between ethylene, abscisic acid and cytokinin during ...

    Indian Academy of Sciences (India)

    10 μM N6-benzyl adenine (BA). .... be noted that in a root inhibition assay, eto1-1 was found to show increased resistance to ABA (Ghassemian ... root and hypocotyl elongation in Arabidopsis but does not account for all the action of cytokinins on ...

  15. ABA-alcohol is an intermediate in abscisic acid biosynthesis

    International Nuclear Information System (INIS)

    Rock, C.D.; Zeevaart, J.A.D.

    1990-01-01

    It has been established that ABA-aldehyde is a precursor to ABA. The ABA-deficient flacca and sitiens mutants of tomato are blocked in the conversion of ABA-aldehyde to ABA, and accumulate trans-ABA-alcohol. 18 O-Labeling studies of ABA in flacca and sitiens show that these mutants synthesize a large percentage of [ 18 O]ABA which contains two 18 O atoms in the carboxyl group. Furthermore, the mutants synthesize much greater amounts of trans-ABA-glucose ester (t-ABA-GE) compared with the wild type, and this [ 18 O]t-ABA-GE is also double labeled in the carboxyl group. Our interpretation of these data is that the 18 O in ABA-aldehyde is trapped in the side chain by reduction to [ 18 O]ABA-alcohol, followed by isomerization to [ 18 O]t-ABA-alcohol and oxidation with 18 O 2 to [ 18 O]t-ABA. The [ 18 O]t-ABA is then rapidly converted to [ 18 O]t-ABA-GE. Because [ 18 O]ABA doubly labeled in the carboxyl group has been observed in small amounts in labeling experiments with several species, and various species have been shown to convert ABA-aldehyde to ABA-alcohol and t-ABA-alcohol, we propose that ABA-alcohol is an ABA intermediate in a shunt pathway

  16. WRKY Transcription Factors: Key Components in Abscisic Acid Signaling

    Science.gov (United States)

    2011-01-01

    Sciences, University of Nevada, Las Vegas, NV, USA 3Environmental Laboratory, Engineer Research and Development Center, US Army Corps of Engineers...galactinol synthase (BhGolS1) promoter. Planta , 230, 1155–1166. Wu, F.-Q., Xin, Q., Cao, Z., Liu, Z.-Q., Du, S.-Y., Mei, C., Zhao, C.-X., Wang, X.-F

  17. Heme and menaquinone induced electron transport in lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Santos Filipe

    2009-05-01

    Full Text Available Abstract Background For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Results Heme- (and menaquinone stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacilllus brevis, Lactobacillus paralimentarius, Streptococcus entericus and Lactococcus garviae. The increased biomass production without further acidification, which are respiration associated traits, are suitable for high-throughput screening as demonstrated by the screening of 8000 Lactococcus lactis insertion mutants. Respiration-negative insertion-mutants were found with noxA, bd-type cytochrome and menaquinol biosynthesis gene-disruptions. Phenotypic screening and in silico genome analysis suggest that respiration can be considered characteristic for certain species. Conclusion We propose that the cyd-genes were present in the common ancestor of lactic acid bacteria, and that multiple gene-loss events best explains the observed distribution of these genes among the species.

  18. Reactivity of H atoms and hydrated electrons with chlorobenzoic acids

    DEFF Research Database (Denmark)

    Zona, R.; Solar, S.; Getoff, N.

    2008-01-01

    H radicals react with chlorobenzoic acids and chlorobenzene (k(H-center dot + substrates) = (0.7-1.5) x 10(9) dm(3) Mol(-1) s(-1)) by addition to the benzene ring forming H adducts with characteristic absorption bands in the range of 310-360 nm. The rate constants for their second-order decay are 2...

  19. The Short-Chain Alcohol Dehydrogenase ABA2 Catalyzes the Conversion of Xanthoxin to Abscisic AldehydeW⃞

    Science.gov (United States)

    González-Guzmán, Miguel; Apostolova, Nadezda; Bellés, José M.; Barrero, José M.; Piqueras, Pedro; Ponce, María R.; Micol, José L.; Serrano, Ramón; Rodríguez, Pedro L.

    2002-01-01

    Mutants able to germinate and perform early growth in medium containing a high NaCl concentration were identified during the course of two independent screenings and named salt resistant (sre) and salobreño (sañ). The sre and sañ mutants also were able to germinate in high-osmoticum medium, indicating that they are osmotolerant in a germination assay. Complementation analyses revealed that sre1-1, sre1-2, sañ3-1, and sañ3-2 were alleles of the abscisic acid (ABA) biosynthesis ABA2 gene. A map-based cloning strategy allowed the identification of the ABA2 gene and molecular characterization of four new aba2 alleles. The ABA2 gene product belongs to the family of short-chain dehydrogenases/reductases, which are known to be NAD- or NADP-dependent oxidoreductases. Recombinant ABA2 protein produced in Escherichia coli exhibits a Km value for xanthoxin of 19 μM and catalyzes in a NAD-dependent manner the conversion of xanthoxin to abscisic aldehyde, as determined by HPLC–mass spectrometry. The ABA2 mRNA is expressed constitutively in all plant organs examined and is not upregulated in response to osmotic stress. The results of this work are discussed in the context of previous genetic and biochemical evidence regarding ABA biosynthesis, confirming the xanthoxin→abscisic aldehyde→ABA transition as the last steps of the major ABA biosynthetic pathway. PMID:12172025

  20. Determination of ascorbic acid and acetylsalicylic acid in commercial preparations using an electronic tongue

    OpenAIRE

    Pereira, Olívia R.; Gomes, Cláudia; Gonçalves, Cristina; Borlido, Diana; Batista, Marta; Teixeira, Tatiana; Dias, L.G.

    2014-01-01

    The electronic tongue is a multi-sensors system used to identify the basic standards of taste, such as sweet, salty, sour and bitter, at levels not detectable by humans. Although the main purpose of electronic tongue is the qualitative analysis, the quantitative analysis of substances in a liquid matrix is also possible, having been the subject of these preliminary studies the application of electronic tongue to pharmaceutical products. In this way, the aim of the current study was the quanti...

  1. Oxygen dependency of one-electron reactions generating ascorbate radicals and hydrogen peroxide from ascorbic acid.

    Science.gov (United States)

    Boatright, William L

    2016-04-01

    The effect of oxygen on the two separate one-electron reactions involved in the oxidation of ascorbic acid was investigated. The rate of ascorbate radical (Asc(-)) formation (and stability) was strongly dependent on the presence of oxygen. A product of ascorbic acid oxidation was measurable levels of hydrogen peroxide, as high as 32.5 μM from 100 μM ascorbic acid. Evidence for a feedback mechanism where hydrogen peroxide generated during the oxidation of ascorbic acid accelerates further oxidation of ascorbic acid is also presented. The second one-electron oxidation reaction of ascorbic acid leading to the disappearance of Asc(-) was also strongly inhibited in samples flushed with argon. In the range of 0.05-1.2 mM ascorbic acid, maximum levels of measurable hydrogen peroxide were achieved with an initial concentration of 0.2 mM ascorbic acid. Hydrogen peroxide generation was greatly diminished at ascorbic acid levels of 0.8 mM or above. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Evaluation of the Efficiency of Electron Beam Irradiation for Removal of Humic Acid from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Mohammad hasan Ehrampoosh

    2017-05-01

    Full Text Available Background: Humic acids (HAs have adverse effects on the environment; therefore, they should be removed from the water and wastewater. The aim of this study was to evaluate the efficiency of the electron beam irradiation for removal of humic acid from aqueous solutions. Methods: Humic acid was purchased from Sigma-Aldrich Company. After preparation of stock solution in alkaline condition, different concentrations of humic acid (10, 25 and 50 mg were prepared. Study has done at pH= 8 and in different dose rates of 1, 3, 6, 9 and 15 kGy. Then initial absorption of samples was measured at 254 nm using UV-Visible spectrophotometer before and after the irradiation. Excel and SPSS Ver. 18 were used for analyzing the data and drawing graphs. Results: The results of this study showed that by increasing adsorbed dose from 1 to 15 kGy, the efficiency of HA removal increased and by increasing humic acid concentration from 10 to 50 mg/L, the removal efficiency of humic acid decreased. The results of the kinetic study showed that irradiation of humic acid followed pseudo second-order reaction. Conclusion: It can be concluded that electron beam irradiation can be a useful technology for the treatment of environmental samples contaminated by humic acid.

  3. Electron transfer reactions of ruthenium(II) complexes with polyphenolic acids in micelles

    Energy Technology Data Exchange (ETDEWEB)

    Rajeswari, Angusamy [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Department of Chemistry, Fatima College, Madurai 625 018 (India); Ramdass, Arumugam [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Research Department of Chemistry, Aditanar College of Arts and Science, Tiruchendur 628 216 (India); Muthu Mareeswaran, Paulpandian [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Rajagopal, Seenivasan, E-mail: rajagopalseenivasan@yahoo.com [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India)

    2016-02-15

    The electron transfer in a microhetrogeneous system is a perfect mimic of biological electron transfer. The electron transfer between biologically important phenolic acids and ruthenium (II) complexes is systematically studied in the presence of anionic and cationic micelles. The photophysical properties of these ruthenium (II) complexes with anionic and cationic micelles and their binding abilities with these two type of micelles are also studies using absorption, emission and excited state lifetime spectral techniques. Pseudophase Ion Exchange (PIE) Model is applied to derive mechanism of electron transfer in two types of micelles. - Highlights: • Effect of microhetrogeneous system is studied using ruthenium (II) complexes and gallic acid is studied. • Pseudophase Ion exchange model is applied to derive the mechanism. • Binding constants are in the range of 10{sup 2}–10{sup 4} M{sup −1}.

  4. Acetic Acid Detection Threshold in Synthetic Wine Samples of a Portable Electronic Nose

    Directory of Open Access Journals (Sweden)

    Miguel Macías Macías

    2012-12-01

    Full Text Available Wine quality is related to its intrinsic visual, taste, or aroma characteristics and is reflected in the price paid for that wine. One of the most important wine faults is the excessive concentration of acetic acid which can cause a wine to take on vinegar aromas and reduce its varietal character. Thereby it is very important for the wine industry to have methods, like electronic noses, for real-time monitoring the excessive concentration of acetic acid in wines. However, aroma characterization of alcoholic beverages with sensor array electronic noses is a difficult challenge due to the masking effect of ethanol. In this work, in order to detect the presence of acetic acid in synthetic wine samples (aqueous ethanol solution at 10% v/v we use a detection unit which consists of a commercial electronic nose and a HSS32 auto sampler, in combination with a neural network classifier (MLP. To find the characteristic vector representative of the sample that we want to classify, first we select the sensors, and the section of the sensors response curves, where the probability of detecting the presence of acetic acid will be higher, and then we apply Principal Component Analysis (PCA such that each sensor response curve is represented by the coefficients of its first principal components. Results show that the PEN3 electronic nose is able to detect and discriminate wine samples doped with acetic acid in concentrations equal or greater than 2 g/L.

  5. The Physical Characterization of Liposome Salicylic Acid Using Transmission Electron Microscope

    International Nuclear Information System (INIS)

    Elman Panjaitan

    2008-01-01

    The physical characterization of liposome, formulated from salicylic acid using thin film hydration methods with cholesterol and soybean lecithin, has been done. The formula was characterized by optical microscopes and Transmission Electron Microscope (TEM). The observation result shows that the salicylic acid can be formulated to liposomes. Soybean lecithin combined with cholesterol (600 mg : 20 mg) was the best formula and the liposome was spherical vesicle like with dimension about 70 nm unit 800 nm. (author)

  6. Graphene for amino acid biosensing: Theoretical study of the electronic transport

    Science.gov (United States)

    Rodríguez, S. J.; Makinistian, L.; Albanesi, E. A.

    2017-10-01

    The study of biosensors based on graphene has increased in the last years, the combination of excellent electrical properties and low noise makes graphene a material for next generation electronic devices. This work discusses the application of a graphene-based biosensor for the detection of amino acids histidine (His), alanine (Ala), aspartic acid (Asp), and tyrosine (Tyr). First, we present the results of modeling from first principles the adsorption of the four amino acids on a graphene sheet, we calculate adsorption energy, substrate-adsorbate distance, equilibrium geometrical configurations (upon relaxation) and densities of states (DOS) for each biomolecule adsorbed. Furthermore, in order to evaluate the effects of amino acid adsorption on the electronic transport of graphene, we modeled a device using first-principles calculations with a combination of Density Functional Theory (DFT) and Nonequilibrium Greens Functions (NEGF). We provide with a detailed discussion in terms of transmission, current-voltage curves, and charge transfer. We found evidence of differences in the electronic transport through the graphene sheet due to amino acid adsorption, reinforcing the possibility of graphene-based sensors for amino acid sequencing of proteins.

  7. Dissociative electron attachment and anion-induced dimerization in pyruvic acid

    Czech Academy of Sciences Publication Activity Database

    Zawadzki, Mateusz; Ranković, Miloš; Kočišek, Jaroslav; Fedor, Juraj

    2018-01-01

    Roč. 20, č. 10 (2018), s. 6838-6844 ISSN 1463-9076 R&D Projects: GA ČR GA17-04844S; GA ČR GJ16-10995Y Institutional support: RVO:61388955 Keywords : pyruvic acid * electron attachment * dimerization Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  8. Optical Absorption and Electron Injection of 4-(Cyanomethylbenzoic Acid Based Dyes: A DFT Study

    Directory of Open Access Journals (Sweden)

    Yuehua Zhang

    2015-01-01

    Full Text Available Density functional theory (DFT and time-dependent density functional theory (TDDFT calculations were carried out to study the ground state geometries, electronic structures, and absorption spectra of 4-(cyanomethylbenzoic acid based dyes (AG1 and AG2 used for dye-sensitized solar cells (DSSCs. The excited states properties and the thermodynamical parameters of electron injection were studied. The results showed that (a two dyes have uncoplanar structures along the donor unit and conjugated bridge space, (b two sensitizers exhibited intense absorption in the UV-Vis region, and (c the excited state oxidation potential was higher than the conduction band edge of TiO2 photoanode. As a result, a solar cell based on the 4-(cyanomethylbenzoic acid based dyes exhibited well photovoltaic performance. Furthermore, nine dyes were designed on the basis of AG1 and AG2 to improve optical response and electron injection.

  9. Effect of three Electron Shuttles on Bioreduction of Ferric Iron in two Acidic and Calcareous soils

    Directory of Open Access Journals (Sweden)

    Setareh Sharifi

    2017-01-01

    Full Text Available Introduction: Iron cycle is one of the most important biogeochemical processes which affect the availability of iron in soils. Ferric iron oxides are the most abundant forms of iron in soils and sediments. Ferric iron is highly insoluble at circumneutral pH. Present investigations have shown that the structural ferric iron bound in clay minerals is reduced by some microorganisms. Anaerobic bacteria reduce ferric iron which bound to soil clay minerals under anaerobic conditions. They have the ability to use ferric iron as a terminal electron acceptor. Many studies presented that dissimilatory iron reducing bacteria (DIRB mediate the transfer of electrons from small organic molecules like acetate and glucose to various humic materials (electron shuttles which then pass electrons abiotically to ferric iron oxyhydroxide and phyllosilicate minerals. Electron shuttles like AQDS, a tricyclic quinone, increase the rate of iron reduction by iron reducing bacteria on sites of iron oxides and oxyhydroxides. By increasing the rate of bioreduction of ferric iron, the solubility and availability of iron enhanced meaningfully. Royer et al. (2002 showed that bioreduction of hematite (common iron mineral in soils increased more than three times in the presence of AQDS and Shewanella putrefaciens comparedto control treatments. Previous works have mostly used synthetic minerals as electron acceptor in bioreduction process. Furthermore, the effect of quinones as electron acceptor for microorganisms were studied with poorly crystalline ferric iron oxides . The main objective of this study was to study the effect of AQS, humic acid and fulvic acid (as electron shuttle and Shewanella sp. and Pseudomonas aeruginosa, on bioreduction of native ferric iron in two acidic and calcareous soils. Materials and Methods: An experiment was conducted in a completely randomized design with factorial arrangement and three replications in vitro condition. The soil samples collected

  10. Complex internal rearrangement processes triggered by electron transfer to acetic acid

    Science.gov (United States)

    Limão-Vieira, P.; Meneses, G.; Cunha, T.; Gil, A.; Calhorda, M. J.; García, G.; Ferreira da Silva, F.

    2015-09-01

    We present negative ion formation from collisions of 100 eV neutral potassium atoms with acetic acid (CH3COOH) and its deuterated analogue molecules (CH3COOD, CD3COOH). From the negative ion time-of-flight (TOF) mass spectra, OH- is the main fragment detected accounting on average for more than 25% of the total anion yield. The complex internal rearrangement processes triggered by electron transfer to acetic acid have been evaluated with the help of theoretical calculations at the DFT levels explaining the fragmentation channel yielding OH-.

  11. DFT studies on the vibrational and electronic spectra of acetylsalicylic acid

    Science.gov (United States)

    Ye, Yunfeng; Tang, Guodong; Han, Yonghong; Culnane, Lance F.; Zhao, Jianyin; Zhang, Yu

    2016-05-01

    The following is a theoretical and experimental study on the vibrational and electronic properties of acetylsalicylic acid (ASA). Vibrational information was obtained by FT-IR and Raman spectroscopy which agree well with harmonic vibrational frequency calculations. The calculations were carried out using density functional theory B3LYP methods with 6-311G** and LANL2DZ basis sets. The vibrational assignments were calculated by Gaussview. Absorption UV-Vis experiments of ASA reveal three maximum peaks at 203, 224 and 277 nm, which are in agreement with calculated electronic transitions using TD-B3LYP/6-311G**.

  12. Scanning Electron Microscopic Evaluation of Root Canal Irrigation with Saline, Sodium Hypochlorite, and Citric Acid,

    Science.gov (United States)

    1983-12-01

    endodontic techniques; citric acid for root canal irrigation 4410,ABSTACgmf --,-,m- ,-rms n roc"---’This Study used a scanning electron microscope and a...wall is instrumented during canal preparation and that the smeared layer seems to be found only where endodontic instruments have scraped the surface...between the extremes. It was also decided to use a magnification of 75X to evaluate the superficial debris and 800X to evaluate the smeared layer

  13. Flocculation Efficiency of Poly(Acrylamide-Co-Acrylic Acid Obtained by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Gabriela Craciun

    2013-01-01

    Full Text Available A correlation between physicochemical characteristics of flocculants obtained by electron beam irradiation and their efficiency for wastewater treatment is presented. For real wastewater treatment, our interest was focused upon total suspended solids, fatty matter, and chemical oxygen demand. Flocculation studies were carried out using a standard jar test. A treatment option based on poly(acrylamide-co-acrylic acid for wastewater taken from a slaughterhouse plant is presented.

  14. Proton-coupled electron transfer promotes the reduction of ferrylmyoglobin by uric acid under physiological conditions

    DEFF Research Database (Denmark)

    de Zawadzki, Andressa; Cardoso, Daniel R.; Skibsted, Leif Horsfelt

    2017-01-01

    The hypervalent muscle pigment ferrylmyoglobin, MbFe(IV)]O, is not reduced by urate monoanions at physiological conditions despite a strong driving force of around 30 kJ mol1 while for low pH, uric acid was found to reduce protonated ferrylmyoglobin, MbFe(IV)]O,H+, efficiently in a bimolecular...... reaction with k1 ¼ 1.1 0.1 103 L mol1 s1, DH‡ ¼ 66.1 0.1 kJ mol1 and DS‡ ¼ 35.2 0.2 J mol1 K1. For intermediate pH, like for anaerobic muscles and for meat, proton-oupled electron transfer occurs in a transition state, {MbFe(IV)]O/H+/urate}‡, which is concluded to be formed from uric acid and Mb...... in uric acid concentration may serve as an inherent protection against radical formation by ferrylmyoglobin...

  15. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

    2011-11-15

    Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  16. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    International Nuclear Information System (INIS)

    Cervantes, Francisco J.; Mancilla, Ana Rosa; Toro, E. Emilia Rios-del; Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia

    2011-01-01

    Highlights: → Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. → Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. → Several species from classes β-, δ- and γ-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 μM of benzene were degraded, which corresponds to 279 ± 27 micro-electron equivalents (μEq) L -1 , linked to the reduction of 619 ± 81 μEq L -1 of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two γ-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes β-, δ- and γ-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  17. Algae as an electron donor promoting sulfate reduction for the bioremediation of acid rock drainage

    Energy Technology Data Exchange (ETDEWEB)

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, Jim A., E-mail: jimfield@email.arizona.edu

    2016-11-05

    Highlights: • Algal biomass can serve as an electron donor to drive reduction of sulfate to sulfide. • Biogenic sulfide precipitates Cu{sup 2+} as stable sulfide mineral. • Cu{sup +2} removal in sulfidogenic bioreactors amended with algal biomass exceeded 99.5%. • Acidity in synthetic acid rock drainage was consumed by sulfate reduction. - Abstract: This study assessed bioremediation of acid rock drainage in simulated permeable reactive barriers (PRB) using algae, Chlorella sorokiniana, as the sole electron donor for sulfate-reducing bacteria. Lipid extracted algae (LEA), the residues of biodiesel production, were compared with whole cell algae (WCA) as an electron donor to promote sulfate-reducing activity. Inoculated columns containing anaerobic granular sludge were fed a synthetic medium containing H{sub 2}SO{sub 4} and Cu{sup 2+}. Sulfate, sulfide, Cu{sup 2+} and pH were monitored throughout the experiment of 123 d. Cu recovered in the column packing at the end of the experiment was evaluated using sequential extraction. Both WCA and LEA promoted 80% of sulfate removal (12.7 mg SO{sub 4}{sup 2−} d{sup −1}) enabling near complete Cu removal (>99.5%) and alkalinity generation raising the effluent pH to 6.5. No noteworthy sulfate reduction, alkalinity formation and Cu{sup 2+} removal were observed in the endogenous control. In algae amended-columns, Cu{sup 2+} was precipitated with biogenic H{sub 2}S produced by sulfate reduction. Formation of CuS was evidenced by sequential extraction and X-ray diffraction. LEA and WCA provided similar levels of electron donor based on the COD balance. The results demonstrate an innovative passive remediation system using residual algae biomass from the biodiesel industry.

  18. Algae as an electron donor promoting sulfate reduction for the bioremediation of acid rock drainage

    International Nuclear Information System (INIS)

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, Jim A.

    2016-01-01

    Highlights: • Algal biomass can serve as an electron donor to drive reduction of sulfate to sulfide. • Biogenic sulfide precipitates Cu 2+ as stable sulfide mineral. • Cu +2 removal in sulfidogenic bioreactors amended with algal biomass exceeded 99.5%. • Acidity in synthetic acid rock drainage was consumed by sulfate reduction. - Abstract: This study assessed bioremediation of acid rock drainage in simulated permeable reactive barriers (PRB) using algae, Chlorella sorokiniana, as the sole electron donor for sulfate-reducing bacteria. Lipid extracted algae (LEA), the residues of biodiesel production, were compared with whole cell algae (WCA) as an electron donor to promote sulfate-reducing activity. Inoculated columns containing anaerobic granular sludge were fed a synthetic medium containing H 2 SO 4 and Cu 2+ . Sulfate, sulfide, Cu 2+ and pH were monitored throughout the experiment of 123 d. Cu recovered in the column packing at the end of the experiment was evaluated using sequential extraction. Both WCA and LEA promoted 80% of sulfate removal (12.7 mg SO 4 2− d −1 ) enabling near complete Cu removal (>99.5%) and alkalinity generation raising the effluent pH to 6.5. No noteworthy sulfate reduction, alkalinity formation and Cu 2+ removal were observed in the endogenous control. In algae amended-columns, Cu 2+ was precipitated with biogenic H 2 S produced by sulfate reduction. Formation of CuS was evidenced by sequential extraction and X-ray diffraction. LEA and WCA provided similar levels of electron donor based on the COD balance. The results demonstrate an innovative passive remediation system using residual algae biomass from the biodiesel industry.

  19. Probing the molecular and electronic structure of the lichen metabolite usnic acid: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Galasso, V., E-mail: galasso@univ.trieste.it [Dipartimento di Scienze Chimiche, Universita di Trieste, I-34127 Trieste (Italy)

    2010-08-23

    Graphical abstract: DFT calculations of structural preferences, acidic properties, carbonyl vibrations, {sup 13}C NMR chemical shifts, and absorption spectrum account for the unique structural backbone, chemical behaviour, and spectroscopic properties of usnic acid, the cortical pigment and potent reactive of lichens. - Abstract: The molecular structure of usnic acid was investigated by the density functional theory (DFT). Two keto-enol tautomers are nearly isoenergetic and more stable than other tautomers. Noteworthy is the energy difference among the three intramolecular O-H...O hydrogen bonds. The DFT/PCM calculated dissociation constants account for the acidic sequence of the three OH-groups. The electronic structure was also studied by calculating IR/Raman, NMR, and absorption features. A reliable assignment of the 'fingerprint' carbonyl stretching modes was supported by calculations on related molecules. The calculated NMR chemical shifts fit expectation in terms of a fast interconversion between the two most preferred tautomers. A variety of {pi} {yields} {pi}* and n {yields} {pi}* excitations, localized on a single ring or involving a charge-transfer between the two lateral rings of the molecule, gives rise to the broad UV-absorption bands. This property accounts for the efficient protection against damaging solar radiation provided by usnic acid for lichens.

  20. Critical evaluation of dipolar, acid-base and charge interactions I. Electron displacement within and between molecules, liquids and semiconductors.

    Science.gov (United States)

    Rosenholm, Jarl B

    2017-09-01

    Specific dipolar, acid-base and charge interactions involve electron displacements. For atoms, single bonds and molecules electron displacement is characterized by electronic potential, absolute hardness, electronegativity and electron gap. In addition, dissociation, bonding, atomization, formation, ionization, affinity and lattice enthalpies are required to quantify the electron displacement in solids. Semiconductors are characterized by valence and conduction band energies, electron gaps and average Fermi energies which in turn determine Galvani potentials of the bulk, space charge layer and surface states. Electron displacement due to interaction between (probe) molecules, liquids and solids are characterized by parameters such as Hamaker constant, solubility parameter, exchange energy density, surface tension, work of adhesion and immersion. They are determined from permittivity, refractive index, enthalpy of vaporization, molar volume, surface pressure and contact angle. Moreover, acidic and basic probes may form adducts which are adsorbed on target substrates in order to establish an indirect measure of polarity, acidity, basicity or hydrogen bonding. Acidic acceptor numbers (AN), basic donor numbers (DN), acidic and basic "electrostatic" (E) and "covalent" (C) parameters determined by enthalpy of adduct formation are considered as general acid-base scales. However, the formal grounds for assignments as dispersive, Lifshitz-van der Waals, polar, acid, base and hydrogen bond interactions are inconsistent. Although correlations are found no of the parameters are mutually fully compatible and moreover the enthalpies of acid-base interaction do not correspond to free energies. In this review the foundations of different acid-base parameters relating to electron displacement within and between (probe) molecules, liquids and (semiconducting) solids are thoroughly investigated and their mutual relationships are evaluated. Copyright © 2017 Elsevier B.V. All rights

  1. Metabolism of fructophilic lactic acid bacteria isolated from Apis mellifera L. bee-gut: a focus on the phenolic acids as external electron acceptors.

    Science.gov (United States)

    Filannino, Pasquale; Di Cagno, Raffaella; Addante, Rocco; Pontonio, Erica; Gobbetti, Marco

    2016-09-16

    Fructophilic lactic acid bacteria (FLAB) are strongly associated to the gastrointestinal tract (GIT) of Apis mellifera L. worker bees due to the consumption of fructose as a major carbohydrate. Seventy-seven presumptive lactic acid bacteria (LAB) were isolated from GIT of healthy A. mellifera L. adults, which were collected from 5 different geographical locations of Apulia region (Italy). Almost all the isolates showed fructophilic tendencies, which were identified as Lactobacillus kunkeei (69%) or Fructobacillus fructosus (31%). A high-throughput phenotypic microarray, targeting 190 carbon sources, was used to determine that 83 compounds were differentially consumed. Phenotyping grouped the strains into two clusters, reflecting growth performance. The utilization of phenolic acids, such as p-coumaric, caffeic, syringic or gallic acids, as electron acceptors was investigated in fructose based medium. Almost all FLAB strains showed tolerance to high phenolic acid concentrations. p-Coumaric acid and caffeic acid were consumed by all FLAB strains through reductases or decarboxylases. Syringic and gallic acids were partially metabolized. The data collected suggest that FLAB require external electron acceptors to regenerate NADH. The use of phenolic acids as external electron acceptors by 4 FLAB, showing the highest phenolic acid reductase activity, was investigated in glucose based medium supplemented with p-coumaric acid. Metabolic responses observed through phenotypic microarray suggested that FLAB may use p-coumaric acid as external electron acceptor, enhancing glucose dissimilation but less efficiently than other external acceptors such as fructose or pyruvic acid. Fructophilic lactic acid bacteria (FLAB) remain to be fully explored. This study intends to link unique biochemical features of FLAB with their habitat. The quite unique FLAB phenome within the lactic acid bacteria (LAB) group may have practical relevance in food fermentations. The FLAB phenome may have

  2. Why is sulfuric acid a much stronger acid than ethanol? Determination of the contributions by inductive/field effects and electron-delocalization effects.

    Science.gov (United States)

    Lynch, Kevin; Maloney, Adam; Sowell, Austin; Wang, Changwei; Mo, Yirong; Karty, Joel M

    2015-01-07

    Two different and complementary computational methods were used to determine the contributions by inductive/field effects and by electron-delocalization effects toward the enhancement of the gas-phase deprotonation enthalpy of sulfuric acid over ethanol. Our alkylogue extrapolation method employed density functional theory calculations to determine the deprotonation enthalpy of the alkylogues of sulfuric acid, HOSO2-(CH2CH2)n-OH, and of ethanol, CH3CH2-(CH2CH2)n-OH. The inductive/field effect imparted by the HOSO2 group for a given alkylogue of sulfuric acid was taken to be the difference in deprotonation enthalpy between corresponding (i.e., same n) alkylogues of sulfuric acid and ethanol. Extrapolating the inductive/field effect values for the n = 1-6 alkylogues, we obtained a value of 51.0 ± 6.4 kcal mol(-1) for the inductive/field effect for n = 0, sulfuric acid, leaving 15.4 kcal mol(-1) as the contribution by electron-delocalization effects. Our block-localized wavefunction method was employed to calculate the deprotonation enthalpies of sulfuric acid and ethanol using the electron-localized acid and anion species, which were compared to the values calculated using the electron-delocalized species. The contribution from electron delocalization was thus determined to be 18.2 kcal mol(-1), which is similar to the value obtained from the alkylogue extrapolation method. The two methods, therefore, unambiguously agree that both inductive/field effects and electron-delocalization effects have significant contributions to the enhancement of the deprotonation enthalpy of sulfuric acid compared with ethanol, and that the inductive/field effects are the dominant contributor.

  3. Electron beam treatment technology for exhaust gas for preventing acid rain

    International Nuclear Information System (INIS)

    Aoki, Shinji

    1990-01-01

    Recently, accompanying the increase of the use of fossil fuel, the damage due to acid rain such as withering of trees and extinction of fishes and shells has occurred worldwide, and it has become a serious problem. The sulfur oxides and nitrogen oxides contained in exhaust gas are oxidized by the action of sunbeam to become sulfuric acid and nitric acid mists, which fall in the form of rain. Acid rain is closely related to the use of the coal containing high sulfur, and it hinders the use of coal which is rich energy source. In order to simplify the processing system for boiler exhaust gas and to reduce waste water and wastes, Ebara Corp. developed the dry simultaneous desulfurizing and denitrating technology utilizing electron beam in cooperation with Japan Atomic Energy Research Institute. The flow chart of the system applied to the exhaust gas treatment in a coal-fired thermal power station is shown. The mechanism of desulfurization and denitration, and the features of this system are described. The demonstration plant was constructed in a coal-fired thermal power station in Indianapolis, Indiana, USA, and the trial operation was completed in July, 1987. The test results are reported. (K.I.)

  4. Study On The Electro-Refining Of Tin In Acid Solution From Electronic Waste

    Directory of Open Access Journals (Sweden)

    Son Seong Ho

    2015-06-01

    Full Text Available The tin metal could be retractable from wasted tin scrap, sludge, and wasted electroplated solution hydrometallurgical treatment, and purification process. In order to be used as resource of electronic devices, the retracted crude metal should be purified to the extent of higher than 99.9%. In this study, tin electro-refining process was performed to purify the casted tin crude metal at various experimental conditions: at the current density of 3, 5A/dm2, and in various electrolytes such as hydrochloric acid, sulfuric acid and methansulfonic acid. Additional experiment was conducted using Rotating Disk Electrode (RDE in order to investigate the rate determining step of tin electro-refining process. The current efficiency, 65.6%, was achievable at the condition of current density, 5A/dm2, and in the electrolyte of Hydrochloric acid. During tin electro-refining process, impurity dissolved from tin crude metal into the electrolyte was analyzed using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES, and the result showed the concentration of impurity metal gradually increased. Quantitative analysis on casted tin crude metal showed that it consists of tin with 93.9 wt.% and several impurity metals of Ag, Bi, Pb, Cu, and etc. After tin electro-refining process, the purity of tin increased up to 99.985 wt.%.

  5. Electronic effects of the functional groups in ortho-Nitrobenzenesulfonic acids on the results of NBO analysis

    Science.gov (United States)

    Ivanov, S. N.; Giricheva, N. I.; Fedorov, M. S.; Men'shikova, I. A.; Nurkevich, T. V.; Tarasova, E. G.

    2013-04-01

    An NBO analysis of electronic density distribution is performed for gaseous benzenesulfonic acid and its mono- and trinitro-substituted molecules (B3LYP, MP2, HF /cc-pVTZ). The energy of orbital inter-actions of nitro and sulfonic groups with benzene ring orbitals is calculated for the most stable acid conformers, and the contributions of inductive and resonance effects of substituents are determined. The dependences of these contributions on the positions and number of nitro groups in an aromatic ring and the possibility of intramolecular hydrogen bond formation are revealed. The nitro group in nitrobenzene exhibits a stronger electron-acceptor effect than the sulfonic group in benzenesulfonic acid. Under the influence of the strong electron-acceptor properties of the nitrogroups, the sulfonic group has a donating effect in ortho-nitrosubstituted benzenesulfonic acids.

  6. Enamel deproteinization before acid etching--a scanning electron microscopic observation.

    Science.gov (United States)

    Ahuja, Bhoomika; Yeluri, Ramakrishna; Baliga, Sudhindra; Munshi, A K

    2010-01-01

    This study was undertaken to evaluate the topographical features of enamel surface deproteinized with sodium hypochlorite (NaOCl) and etched with phosphoric acid (H3PO4) compared to phosphoric acid alone using Scanning Electron Microscopic (SEM) Analysis. 30 enamel blocks of 1 mm2 from ten human sound extracted permanent molars were obtained and treated as under: Group 1 (10 blocks): Enamel surface was etched with 37% H3PO4 gel for 15 seconds. Group 2 (10 blocks): Enamel surface was treated with 5.25% NaOCl for 60 seconds and then etched with 37% H3PO4 gel for 15 seconds. 10 enamel blocks were included in the control group where no treatment was carried out. The samples were subjected to SEM analysis and 5 microphotographs of each sample were obtained at 500X magnification and evaluated for the quality of etching pattern of the enamel in percentage (%) using Auto-CAD 2007 software. Mean values of etching pattern in Group 1 being 55.76% and Group 2 being 53.58%. No significant difference was observed between the two groups. The use of 37% phosphoric acid for 15 seconds still remains the best method for pretreatment of enamel.

  7. Algae as an electron donor promoting sulfate reduction for the bioremediation of acid rock drainage.

    Science.gov (United States)

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, Jim A

    2016-11-05

    This study assessed bioremediation of acid rock drainage in simulated permeable reactive barriers (PRB) using algae, Chlorella sorokiniana, as the sole electron donor for sulfate-reducing bacteria. Lipid extracted algae (LEA), the residues of biodiesel production, were compared with whole cell algae (WCA) as an electron donor to promote sulfate-reducing activity. Inoculated columns containing anaerobic granular sludge were fed a synthetic medium containing H2SO4 and Cu(2+). Sulfate, sulfide, Cu(2+) and pH were monitored throughout the experiment of 123d. Cu recovered in the column packing at the end of the experiment was evaluated using sequential extraction. Both WCA and LEA promoted 80% of sulfate removal (12.7mg SO4(2-) d(-1)) enabling near complete Cu removal (>99.5%) and alkalinity generation raising the effluent pH to 6.5. No noteworthy sulfate reduction, alkalinity formation and Cu(2+) removal were observed in the endogenous control. In algae amended-columns, Cu(2+) was precipitated with biogenic H2S produced by sulfate reduction. Formation of CuS was evidenced by sequential extraction and X-ray diffraction. LEA and WCA provided similar levels of electron donor based on the COD balance. The results demonstrate an innovative passive remediation system using residual algae biomass from the biodiesel industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Electronic Structures and Optical Properties of Phenyl C71 Butyric Acid Methyl Esters

    Directory of Open Access Journals (Sweden)

    Cai-Rong Zhang

    2013-01-01

    Full Text Available Phenyl C71 butyric acid methyl ester (PC71BM has been adopted as electron acceptor materials in bulk heterojunction solar cells with relatively higher power conversion efficiency. The understanding of the mechanism and performance for the devices based upon PC71BM requires the information of conformations, electronic structures, optical properties, and so forth. Here, the geometries, IR and Raman, electronic structures, polarizabilities, and hyperpolarizabilities of PC71BM isomers are studied by using density functional theory (DFT; the absorption and excitation properties are investigated via time-dependent DFT with B3LYP, PBE0, and CAM-B3LYP functionals. The calculated results show that [6,6]PC71BM is more stable than [5,6]PC71BM due to the lower total energy. The vibrational modes of the isomers at IR and Raman peaks are quite similar. As to absorption properties, CAM-B3LYP functional is the suitable functional for describing the excitations of PC71BM because the calculated results with CAM-B3LYP functional agree well with that of the experiment. The analysis of transition configurations and molecular orbitals demonstrated that the transitions at the absorption maxima in UV/Vis region are localized π-π* transitions in fullerenes cages. Furthermore, the larger isotropic polarizability of PC71BM indicates that the response of PC71BM to applied external electric field is stronger than that of PC61BM, and therefore resulting into better nonlinear optical properties.

  9. Electron-beam induced RAFT-graft polymerization of poly(acrylic acid) onto PVDF

    International Nuclear Information System (INIS)

    Grasselli, M.; Betz, N.

    2005-01-01

    This paper explores for the first time the post-radiation-induced-graft polymerization on solid substrate using reversible addition-fragmentation transfer (RAFT) mechanism. Radiation-induced graft polymerization onto polymers is a potentially interesting technique to create easily new materials from highly resistant polymers, e.g. surface graft polymerization of acrylic acid (AA) onto poly(vinylidene difluoride) (PVDF) improves its surface properties without losing its excellent mechanical properties. As a consequence of the radical nature of the polymerization processes it is difficult to control molecular weight of grafted chains, and therefore design and standardize the properties of the final product. RAFT polymerization is a suitable method to obtain monodisperse polymers. The ability of the RAFT agents to control the polymer chain length could be an interesting approach to improve the grafted polymers obtained by post-radiation-induced-graft polymerization technique. In this way, graft polymerization of AA onto electron-beam irradiated α-PVDF was performed using trithiocarbonic acid bis(1-phenylethyl) ester as a RAFT agent to control the radical polymerization. We studied several grafting parameters such as solvent, monomer concentration and grafting time in order to achieve a poly(acrylic acid) (PAA) layer onto PVDF surface. Acetic acid was found to be the best solvent for many reasons, as to drive graft polymerization mainly to the polymer surface, complete solubility and stability of all reactants. Hydrolysis of PAA chains was also studied in order to remove the trithiocarbonate functionality from the grafted polymer. A mild chemical condition was achieved in order to have thiol groups that were detected onto the modified PVDF by specific enzymatic reaction

  10. Analysis of naphthenic acid mixtures as pentafluorobenzyl derivatives by gas chromatography-electron impact mass spectrometry.

    Science.gov (United States)

    Gutierrez-Villagomez, Juan Manuel; Vázquez-Martínez, Juan; Ramírez-Chávez, Enrique; Molina-Torres, Jorge; Trudeau, Vance L

    2017-01-01

    In this study, we report for the first time the efficiency of pentafluorobenzyl bromide (PFBBr) for naphthenic acid (NA) mixtures derivatization, and the comparison in the optimal conditions to the most common NAs derivatization reagents, BF 3 /MeOH and N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA). Naphthenic acids are carboxylic acid mixtures of petrochemical origin. These compounds are important for the oil industry because of their corrosive properties, which can damage oil distillation infrastructure. Moreover, NAs are commercially used in a wide range of products such as paint and ink driers, wood and fabric preservatives, fuel additives, emulsifiers, and surfactants. Naphthenic acids have also been found in sediments after major oils spills in the United States and South Korea. Furthermore, the toxicity of the oil sands process-affected water (OSPW), product of the oil sands extraction activities in Canada's oil sands, has largely been attributed to NAs. One of the main challenges for the chromatographic analysis of these mixtures is the resolution of the components. The derivatization optimization was achieved using surface response analysis with molar ratio and time as factors for derivatization signal yield. After gas chromatography-electron impact mass spectrometry (GC/EIMS) analysis of a mixture of NA standards, it was found that the signal produced by PFB-derivatives was 2.3 and 1.4 times higher than the signal produced by methylated and MTBS-derivatives, respectively. The pentafluorobenzyl derivatives have a characteristic fragment ion at 181m/z that is diagnostic for the differentiation of carboxylic and non-carboxylic acid components within mixtures. In the analysis of a Sigma and a Merichem derivatized oil extract NA mixtures, it was found that some peaks lack the characteristic fragment ion; therefore they are not carboxylic acids. Open column chromatography was used to obtain a hexane and a methanol fraction of the Sigma and

  11. Linking photochemical transformation of an Antarctica Fulvic Acid to diminished bioavailability and oxidation of organic electron shuttles

    Science.gov (United States)

    Fimmen, R. L.; Guerard, J. J.; Miller, P. L.; Cory, R. M.; Chin, Y.; Foreman, C. M.; McKnight, D. M.

    2007-12-01

    Photolysis of fulvic acid isolated from Pony Lake, Antarctica, a hypereutrophic coastal pond located on Ross Island, was evaluated for transformation kinetics and photo-bleaching mechanisms by spectroscopy, as well as changes in bioavailability. The fulvic acid fraction of Pony Lake was isolated by sorption to non-ionic XAD-8 resin, and represents the fraction of the dissolved organic matter considered to be the most photo-reactive fraction. Spectroscopic and electrochemical analysis during Pony Lake fulvic acid photolysis reveals three fundamental alterations to the natural organic matter isolate: decreased molar absorptivity, decreased fluorescence, and a loss of reduced organic functional groups (potential electron shuttles). Surprisingly we observed no carbon loss to mineralization. Evaluation of the light absorbance decay kinetics in the presence/absence of oxygen indicate that approximately 70% of photo-bleaching occurs via direct pathways and 30% is due to reaction with photochemically generated reactive oxygen species (ROS). Of the ROS mediated pathways approximately 70% of the reactivity is attributable to hydroxyl-radical oxidation. Molecular level changes in fulvic acid showed a loss of electron-rich (reduced) components during photolysis, specifically redox active N/S functional groups. Reduced forms of organic nitrogen (amines) decrease in concentration, while sulfur moieties (thiols) are essentially eliminated during photolysis. Furthermore, as the suite of reduced fulvic acid components are photochemically oxidized, we observe a concomitant production of hydrogen peroxide, presumably due to the photo-reduction of dissolved oxygen coupled to organic matter oxidation. Decay kinetics of fluorescent components identified in the fulvic acid isolate were evaluated using parallel factor component analysis (PARAFAC) of excitation-emission matrices (EEMs), and further illustrate a loss of overall fluorescence and a decrease in the redox-active (electron

  12. Flow injection fluorescence determination of dopamine using a photo induced electron transfer (PET) boronic acid derivative

    International Nuclear Information System (INIS)

    Ebru Seckin, Z.; Volkan, Muervet

    2005-01-01

    An automated flow injection analysis system was developed for the fluorometric determination of dopamine in pharmaceutical injections. The method is based on the quenching effect of dopamine on m-dansylaminophenyl boronic acid (DAPB) fluorescence due to the reverse photo induced electron transfer (PET) mechanism. Effects of pH and interfering species on the determination of dopamine were examined. Calibration for dopamine, based on quenching data, was linear in the concentration range of 1.0 x 10 -5 to 1.0 x 10 -4 M. Detection limit (3 s) of the method was found to be 3.7 x 10 -6 M. Relative standard deviation of 1.2% (n = 10) was obtained with 1.0 x 10 -5 M dopamine standard solution. The proposed method was applied successfully for the determination of dopamine in pharmaceutical injection sample. The sampling rate was determined as 24 samples per hour

  13. Studies on effective atomic number, electron density and kerma for some fatty acids and carbohydrates

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2008-01-01

    The effective atomic number, Z(eff), the effective electron density, N-el, and kerma have been calculated for some fatty acids and carbohydrates for photon interaction in the extended energy range from 1 keV to 100 GeV using an accurate database of photon-interaction cross sections and the Win......XCom program. The significant variation of Z(eff) and N-el is due to the variations in the dominance of different interaction processes in different energy regions. The maximum values of Z(eff) and N-el are found in the low-energy range, where photoelectric absorption is the main interaction process....... The minimum values of Z(eff) and N-el are found at intermediate energies, typically 0.05 MeV atomic number of the bio-molecule. Wherever possible, the calculations are compared with experimental results. A comparison...

  14. Experimental Electron Density Distribution in Two Cocrystals of Betaines with p-Hydroxybenzoic Acid

    Directory of Open Access Journals (Sweden)

    Agata Owczarzak

    2018-03-01

    Full Text Available Experimental determination of electron density distribution in crystals by means of high-resolution X-ray diffraction allows, among others, for studying the details of intra- and inter-molecular interactions. In case of co-crystals, this method may help in finding the conditions of creating such species. The results of such analysis for two co-crystals containing betaines, namely trigonelline (TRG: nicotinic acid N-methylbetaine, IUPAC name: 1-methylpyridinium-3-carboxylate and N-methylpiperidine betaine (MPB: 1-methylpiperidinium-1-yl-carboxylate with p-hydroxybenzoic acid (HBA are reported. TRG-HBA crystallizes as a hydrate. For both of the co-crystals, high-quality diffraction data were collected up to sinθ/λ = 1.13 Å−1. Hansen-Coppens multipolar model was then applied for modelling the electron density distribution and Atoms-In-Molecules approach was used for detailed analysis of interactions in crystals. A number of intermolecular interactions was identified, ranging from strong O-H···O hydrogen bonds through C-H···O to C-H···π and π···π interactions. Correlations between the geometrical characteristics of the contacts and the features of their critical points were analyzed in detail. Atomic charges show that in zwitterionic species there are regions of opposite charges, rather than charges that are localized on certain atoms. In case of MPB-HBA, a significant charge transfer between the components of co-crystal (0.5 e was found, as opposed to TRG-HBA, where all of the components are almost neutral.

  15. Conformational, electronic, and spectroscopic characterization of isophthalic acid (monomer and dimer structures) experimentally and by DFT.

    Science.gov (United States)

    Bardak, F; Karaca, C; Bilgili, S; Atac, A; Mavis, T; Asiri, A M; Karabacak, M; Kose, E

    2016-08-05

    Isophthalic acid (C6H4(CO2H)2) is a noteworthy organic compound widely used in coating and synthesis of resins and the production of commercially important polymers such as drink plastic bottles. The effects of isophthalic acid (IPA) on human health, toxicology, and biodegradability are the main focus of many researchers. Because structural and spectroscopic investigation of molecules provides a deep understanding of interactional behaviors of compounds, this study stands for exploring those features. Therefore, the spectroscopic, structural, electronic, and thermodynamical properties of IPA were thoroughly studied in this work experimentally using UV-Vis, (1)H and (13)C NMR, FT-IR, FT-Raman and theoretically via DFT and TD-DFT calculations. The UV-Vis absorption spectrum in water was taken in the region 200-400nm. The NMR chemical shifts ((1)H and (13)C) were recorded in DMSO solution. The infrared and Raman spectra of the solid IPA were recorded in the range of 4000-400cm(-1) and 3500-50cm(-1), respectively. DFT and TD-DFT calculations were performed at the level of B3LYP/6-311++G(d,p) in determination of geometrical structure, electronic structure analysis and normal mode. The (13)C and (1)H nuclear magnetic resonance (NMR) spectra were estimated by using the gauge-invariant atomic orbital (GIAO) method. The scaled quantum mechanics (SQM) method was used to determine the total energy distribution (TED) to assign the vibrational modes accurately. Weak interactions such as hydrogen bonding and Van der Walls were analyzed via reduced density gradient (RDG) analysis in monomeric and dimeric forms. Furthermore, the excitation energies, density of state (DOS) diagram, thermodynamical properties, molecular electro-static potential (MEP), and nonlinear optical (NLO) properties were obtained. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. The effects of solvents and structure on the electronic absorption spectra of the isomeric pyridine carboxylic acid N-oxides

    Directory of Open Access Journals (Sweden)

    Drmanić Saša Ž.

    2013-01-01

    Full Text Available The ultraviolet absorption spectra of the carboxyl group of three isomeric pyridine carboxylic acids N-oxides (picolinic acid N-oxide, nicotinic acid N-oxide and isonicotinic acid N-oxide were determined in fourteen solvents in the wavelength range from 200 to 400 nm. The position of the absorption maxima (λmax of the examined acids showed that the ultraviolet absorption maximum wavelengths of picolinic acid N-oxide are the shortest, and those of isonicotinic acid N-oxide acid are the longest. In order to analyze the solvent effect on the obtained absorption spectra, the ultraviolet absorption frequencies of the electronic transitions in the carboxylic group of the examined acids were correlated using a total solvatochromic equation of the form max = v0 + sπ + aα+ bβ, where υmax is the absorption frequency (1/λmax, p is a measure of the solvent polarity, β represents the scale of solvent hydrogen bond acceptor basicities and α represent the scale of solvent hydrogen bond donor acidities. The correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The solvent effects on the ultraviolet absorption maximums of the examined acids were discussed.

  17. Study on mutual interactions and electronic structures of hyaluronan with Lysine, 6-Aminocaproic acid and Arginine.

    Science.gov (United States)

    Chytil, Martin; Trojan, Martin; Kovalenko, Alexander

    2016-05-20

    Interactions between polyelectrolytes and oppositely charged surfactants have been in a great interest for several decades, yet the conventional surfactants may cause a problem in medical applications. Interactivity between polysaccharide hyaluronan (HA) and amino acids Lysine, 6-Aminocaproic acid (6-AcA), and Arginine as an alternative system is reported. The interactions were investigated by means of rheology and electric conductance and the electronic structures were explored by the density functional theory (DFT). Lysine exhibits the strongest interaction of all, which was manifested, e.g. by nearly 6-time drop of the initial viscosity comparing with only 1.3-time lower value in the case of 6-AcA. Arginine interaction with HA was surprisingly weaker in terms of viscosity than that of Lysine due to a lower and delocalized charge density on its guanidine group. According to the DFT calculations, the binding of Lysine to HA was found to be more flexible, while Arginine creates more rigid structure with HA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. The Investigation of Electron Beam Catalytical Oxidation Process Efficiency with Potassium Persulfate in Removal Humic Acid from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    MT Ghaneian

    2015-05-01

    Results: Based on the results, changes in pH had little effect on the Humic acid removal efficiency. The average, with increasing of pH from 4 to 10, the removal efficiency of humic acid from 72.59% to 73.36% increased, respectively. The results showed that increasing of the dose from 1 to 15 kGy, humic acid removal efficiency increases. Based on results by increasing of persulfate concentration, the removal efficiency increased so that with increasing of concentration of potassium persulfate from 0.1 to 0.5 mmol/100cc, removal efficiency from 69.43% to 83.82% was increased. Kinetic experiments showed that the decomposition of humic acid by electron beam radiation followed the second-order kinetic. Conclusion: The data from this study showed that the aqueous solution containing acid Humic is decomposed effectively by electron beams irradiation. Addition of potassium persulfate can be have significant improvements in removal efficiency of humic acid in the presence of electron beam.

  19. Development of phosphonic acid chelating fibers by means of electron beam irradiation induced graft polymerization technique

    International Nuclear Information System (INIS)

    Jyo, Akinori; Aoki, Shoji; Yamabe, Kazunori; Shuto, Taketomi

    2001-01-01

    Chloromethylstyrene was graft-polymerized onto polyethylene coated polypropylene fibers (0.9 denier) and its nonwoven cloth (1.5 denier) by means of electron beam irradiation induced graft polymerization technique. The grafted fiber and cloth were reacted with phosphorus trichloride in the presence of anhydrous aluminum trichloride under reflux of phosphorus trichloride, and the followed hydrolysis gave the objective phosphonic acid fibrous chelating exchangers FCSP-c (cloth type) and FCSP-f (fiber type) with phosphorus contents of 3.3 ± 0.2 mmol/g and acid capacities of 5.5 ± 0.2 meq/g. Adsorption rates of Pb(II), Cu(II) and Cd(II) by FCSP-c and FCSP-f were evaluated by batchwise and columnar methods, and compared with those by a chelating resin RCSP having the same functional groups. In batchwise and columnar adsorption of these metal ions, both FCSP-c and FCSP-f exhibited extremely higher adsorption rates than did the resin RCSP. For instance, FCSP-f packed columns exhibited flow rate independent breakthrough capacities of ca. 0.7-0.8 mmol/g for Cu(II) and Cd(II) within the tested range of flow rates from 50 to 1000 h -1 in space velocity, whereas breakthrough capacities of a RCSP resin packed one for Cu(II) decreased markedly with an increase in flow rate. For example, the breakthrough capacity of RCSP column at the flow rate of 500 h -1 was only ca. 0.2 mmol/g. (author)

  20. Electronic spectra of plutonium ions in nitric acid and in lithium nitrate solutions

    International Nuclear Information System (INIS)

    Mekhail, F.M.

    1987-01-01

    The absorption spectra of plutonium ions in nitric acid have been described. There is a characteristic change in the absorption spectra of Pu v in lithium nitrate solutions. In 2 M-lithium nitrate a new peak at 969 nm and high absorption at 1200 nm are noticed. A decrease in the absorption by about 20% and the appearance of a new shoulder at 1120 nm in 6 M-lithium nitrate are found. There is no change in the spectrum in 4 M-lithium nitrate. The absorption spectra of plutonium ions in the spectral range 200 - 400 nm are interesting. All plutonium ions have an intense band in the region 250 - 260 nm as well as a less intense and rather diffuse band at 320 - 330 nm in lithium nitrate solutions the sharp band at 250 - 260 nm has disappeared. This suggests that this band is very sensitive to the environmental field. The band is probably produced by 5 F q → 5 f q-1 6 d transition as well as electron transfer. It is believed that the spectrum of Pu V at pH 6.5 represents the hydrolysis product Pu O 2 (O H). 9 fig., 4 tab

  1. Carboxymethyl starch cross-linked by electron beam radiation in presence of acrylic acid sensitizer

    International Nuclear Information System (INIS)

    Doan Binh; Nguyen Thanh Duoc; Pham Thi Thu Hong

    2013-01-01

    Carboxymethyl starch (CMS) can be cross-linked by electron beam radiation to form a biocompatible and environment-friendly hydrogel at a high absorbed dose and a condensed CMS concentration. Acrylic acid (AAc) can be used as a sensitizer in order to reduce the absorbed doses to an acceptable certain level. At an absorbed dose of 3-4 kGy, the gel content of crosslinked CMS can be obtained about 50% with 5% (w/w) AAc concentration used. The compressive strength of CMS samples increased with increasing their cross-linked densities due to raising absorbed doses. The swelling ratio of cross-linked CMS was also attainable at a maximum of 50 times in the distilled water. The enzymatic degradation of cross-linked CMS was carried out in acetate buffer pH 4.6 with 0.1% α-amylase enzymatic solution incubated at 40℃ for 6 h. The crosslinked CMS samples were degraded slower than uncrosslinked CMS ones. The results indicated that the highly cross-linked CMS was almost fully degradable when the enzymatic hydrolysis was performed during 6 h. The FT IR spectra of cross-linked CMS in the presence of AAc were examined to observe the carboxyl group of AAc in the structure of cross-linked CMS. The hydrophilic of cross-linked CMS surface was determined by a contact-angle analysis. (authors)

  2. Electron microscope analyses of insoluble components in acid rain, Guilin City, China

    Science.gov (United States)

    Zheng, Zhang; Yu Hong, Cao

    During the period of 16-29 March 1988 four precipitation systems produced rainfall over Guilin City, China. This rain water had a mean pH of 4.16, which classifies it as acid rain. During each precipitation event samples of rain water were continously collected and filtered. Insoluble impurities were collected on filter paper and 66 samples prepared for electron microscope energy spectrometry analysis. The analytical results show a total of 12 elements present in the samples of rain water, viz. Ar, Mg, Al, Si, P, S, Cl, K, Ca, Fe, Ni and Cr. For the samples as a whole, three major elements (Si, Al and Fe) accounted for about 86% of the average total weight of the 12 elements. Cluster analysis was used to group the analytical results for 115 individual analyses (on relatively coarse-grained sections of the samples) into 9 types of weight-percentage distributions. The cluster analysis showed that: (1) The majority of the weight distributions all belonged to one single type, which made up 75, 63, 65 and 75% of the separate analyses of the four precipitating systems respectively. This suggests that the four precipitating systems formed and eveloped in a similar synoptic situation. (2) Some special samples with characteristic, anomalous, weight distributions were identified from different precipitation systems. This suggests that different pollutant conditions prevailed in the sources and along the trajectories of these four systems.

  3. Controlled release of tyrosol and ferulic acid encapsulated in chitosan-gelatin films after electron beam irradiation

    Science.gov (United States)

    Benbettaïeb, Nasreddine; Assifaoui, Ali; Karbowiak, Thomas; Debeaufort, Frédéric; Chambin, Odile

    2016-01-01

    This work deals with the study of the release kinetics of antioxidants (ferulic acid and tyrosol) incorporated into chitosan-gelatin edible films after irradiation processes. The aim was to determine the influence of electron beam irradiation (at 60 kGy) on the retention of antioxidants in the film, their release in water (pH=7) at 25 °C, in relation with the barrier and mechanical properties of biopolymer films. The film preparation process coupled to the irradiation induced a loss of about 20% of tyrosol but did not affect the ferulic acid content. However, 27% of the ferulic acid remained entrapped in the biopolymer network during the release experiments whereas all tyrosol was released. Irradiation induced a reduction of the release rate for both compounds, revealing that cross-linking occurred during irradiation. This was confirmed by the mechanical properties enhancement which tensile strength value significantly increased and by the reduction of permeabilities. Although molecular weights, molar volume and molecular radius of the two compounds are very similar, the effective diffusivity of tyrosol was 40 times greater than that of ferulic acid. The much lower effective diffusion coefficient of ferulic acid as determined from the release kinetics was explained by the interactions settled between ferulic acid molecules and the gelatin-chitosan matrix. As expected, the electron beam irradiation allowed modulating the retention and then the release of antioxidants encapsulated.

  4. Solar sterilization of abscised fruit: a cultural practice to reduce infestations of Anastrepha obliqua around orchards

    Science.gov (United States)

    Abscised mangoes, Mangifera indica L., of several varieties were stored under varying conditions of insolation, including no sun (stored in a laboratory), shade (stored under the shade of a mango tree), full sun (stored in direct view of the sun), and covered in a black plastic bag and stored in dir...

  5. Analysis of Cytokinin Mutants and Regulation of Cytokinin Metabolic Genes Reveals Important Regulatory Roles of Cytokinins in Drought, Salt and Abscisic Acid Responses, and Abscisic Acid Biosynthesis

    Czech Academy of Sciences Publication Activity Database

    Nishiyama, R.; Watanabe, Y.; Werner, T.; Vaňková, Radomíra; Schmülling, T.; Tran, L. S. P.

    2011-01-01

    Roč. 23, č. 6 (2011), s. 2169-2183 ISSN 1040-4651 Institutional research plan: CEZ:AV0Z50380511 Keywords : TRANSGENIC TOBACCO PLANTS * WATER-STRESS * LEAF SENESCENCE Subject RIV: ED - Physiology Impact factor: 8.987, year: 2011

  6. Preparation of New Adsorbent Containing Hydroxamic Acid Groups by Electron Beam-Induced Grafting for Metal Ion Adsorption

    International Nuclear Information System (INIS)

    Suwanmala, Phiriyatorn; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

    2007-08-01

    Full text: A new adsorbent containing hydroxamic acid groups was synthesized by electron beam-induced graft copolymerization of methyl acrylate (MA) onto nonwoven fabric composed of polyethylene-coated polypropylene fiber. Conversion of ester groups of the grafted copolymer into the hydroxamic groups was performed by treatment with an alkaline solution of hydroxylamine (HA). Adsorbent containing hydroxamic acid groups can adsorb 99% of UO2 2+ , 98% of V5+, 97% of Pb2+ and 96% of Al3+ at pH, 5, 4, 6, and 4, respectively, after coming into contact with 100 ppb metal solution for 24 h

  7. Triggered degradation of 250 μm-thick Mg targets using acetic acid for transient electronic applications

    Directory of Open Access Journals (Sweden)

    Zhiyuan Zhu

    2017-07-01

    Full Text Available Transient electronics are becoming a hot topic due to the rapid development of bioelectronics, self-destructive devices and environmental sensors. This letter reports a novel scheme for triggering degradation of 250 μm-thick Mg target using acetic acid regarding transient electronics applications. The triggered transience has also been demonstrated using commercial vinegar. To achieve programmable transience as well as device protection, polypropylene carbonate (PPC was investigated as passivation layer. The proposed method has demonstrated simplicity, high safety, low cost and low trigger temperature.

  8. Effectiveness of Three Different Irrigants - 17% Ethylenediaminetetraacetic Acid, Q-MIX, and Phytic Acid in Smear Layer Removal: A Comparative Scanning Electron Microscope Study.

    Science.gov (United States)

    Jagzap, Janhavi Balasaheb; Patil, Sanjay S; Gade, Vandana Jaykumar; Chandhok, Deepika J; Upagade, Madhura A; Thakur, Deepa A

    2017-01-01

    Removal of smear layer from the root canal walls is important for long-standing endodontic success. The aim of this study is to evaluate and compare smear layer removing ability among 17% ethylenediaminetetraacetic acid (EDTA), Q-MIX, and phytic acid by scanning electron microscopy (SEM). This in-vitro experimental study assessed smear layer removal using three different irrigants. Thirty single-rooted freshly extracted human permanent premolars were collected, disinfected, and decoronated to a standardized root length of 13 mm. Root canals were cleaned and shaped till F2 universal rotary protaper at working length 1 mm short of the apex. They were randomly divided into three groups, and final irrigation was done accordingly. Group 1 ( n = 10): with 1 ml of 17% EDTA, Group 2 ( n = 10): with 1 ml of Q-MIX, Group 3 ( n = 10): with 1 ml of phytic acid. Samples were then longitudinally sectioned and evaluated under SEM at coronal, middle, and apical levels. Two-way analysis of variance and Tukey's post hoc test were performed. The level of significance was set at 0.05. Smear layer removing ability among irrigants and sections in descending order: 17 EDTA > Q-MIX > phytic acid; coronal > middle > apical. 17% EDTA showed better and promising results followed by Q-MIX and then phytic acid.

  9. Consecutive Fragmentation Mechanisms of Protonated Ferulic Acid Probed by Infrared Multiple Photon Dissociation Spectroscopy and Electronic Structure Calculations

    Science.gov (United States)

    Martens, Sabrina M.; Marta, Rick A.; Martens, Jonathan K.; McMahon, Terry B.

    2012-10-01

    Protonated ferulic acid and its principle fragment ion have been characterized using infrared multiple photon dissociation spectroscopy and electronic structure calculations at the B3LYP/6-311 + G(d,p) level of theory. Due to its extensively conjugated structure, protonated ferulic acid is observed to yield three stable fragment ions in IRMPD experiments. It is proposed that two parallel fragmentation pathways of protonated ferulic acid are being observed. The first pathway involves proton transfer, resulting in the loss of water and subsequently carbon monoxide, producing fragment ions m/z 177 and 149, respectively. Optimization of m/z 177 yields a species containing an acylium group, which is supported by a diagnostic peak in the IRMPD spectrum at 2168 cm-1. The second pathway involves an alternate proton transfer leading to loss of methanol and rearrangement to a five-membered ring.

  10. On the Origin of the Methyl Radical Loss from Deprotonated Ferulic and Isoferulic Acids: Electronic Excitation of a Transient Structure

    Science.gov (United States)

    Zhang, Xiaoping; Li, Fei; Lv, Huiqing; Wu, Yanqing; Bian, Gaofeng; Jiang, Kezhi

    2013-06-01

    Formation of radical fragments from even-electron ions is an exception to the "even-electron rule". In this work, ferulic acid (FA) and isoferulic acid (IFA) were used as the model compounds to probe the fragmentation mechanisms and the isomeric effects on homolytic cleavage. Elimination of methyl radical and CO2 are the two competing reactions observed in the CID-MS of [FA - H]- and [IFA - H]-, of which losing methyl radical violates the "even-electron rule". The relative intensity of their product ions is significantly different, and thereby the two isomeric compounds can be differentiated by tandem MS. Theoretical calculations indicate that both the singlet-triplet gap and the excitation energy decrease in the transient structures, as the breaking C-O bond is lengthened. The methyl radical elimination has been rationalized as the intramolecular electronic excitation of a transient structure with an elongating C-O bond. The potential energy diagrams, completed by the addition of the energy barrier of the radical elimination, have provided a reasonable explanation of the different CID-MS behaviors of [FA - H]- and [IFA - H]-.

  11. Electron-beam-induced post-grafting polymerization of acrylic acid onto the surface of Kevlar fibers

    Science.gov (United States)

    Xu, Lu; Hu, Jiangtao; Ma, Hongjuan; Wu, Guozhong

    2018-04-01

    The surface of Kevlar fibers was successfully modified by electron beam (EB)-induced post-grafting of acrylic acid (AA). The generation of radicals in the fibers was confirmed by electron spin resonance (ESR) measurements, and the concentration of radicals was shown to increase as the absorbed dose increased, but decrease with increasing temperature. The influence of the synthesis conditions on the degree of grafting was also investigated. The surface microstructure and chemical composition of the modified Kevlar fibers were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The SEM images revealed that the surface of the grafted fibers was rougher than those of the pristine and irradiated fibers. XPS analysis confirmed an increase in C(O)OH groups on the surface of the Kevlar fibers, suggesting successful grafting of AA. These results indicate that EB-induced post-grafting polymerization is effective for modifying the surface properties of Kevlar fibers.

  12. IPN's of Acrylic Acid and N-Isopropylacrylamide by Gamma and Electron Beam Irradiation

    International Nuclear Information System (INIS)

    Burillo, G.

    2006-01-01

    In recent years, temperature and pH sensitive hydrogels have been investigated widely because of their unique properties and versatile applications in medicine and biotechnology, as well as drug delivery. However a serious limitation of hydrogels in many applications is the low mechanical strength of such gels when highly swollen. To overcome this problem, sensitive hydrogels were prepared with satisfactory mechanical properties as a semi-interpenetranting network, where one of them is a mechanically stable polymer. In this work temperature sensitive monomer N-isopropylacrylamide (NIPAAm) and a pH sensitive monomer, acrylic acid (AAc) were prepared as an interpenetranting network by a sequential method. Poly (AAc) hydrogels were prepared in glass tubes 3 mm inner diameter, at room temperature from an aqueous solutions 50%vol under argon atmosphere, and irradiated with a Co 6 0 gamma source, at doses from 5 to 30 kGy and dose rate of 3 kGy/h. Poly (AAc) hydrogels were also prepared by electron beam irradiation with a Van de Graaff at a dose rate of 19.4 kGy/min, and radiation doses from 10 to 30 kGy. After polymerization and crosslinking, the gels were washed in water during 48 h, and dried in vacuo to constant weight. Poly (NIPAAm) as secondary gel was synthetized directly within the primary gels in aqueous solution with the croslinker N, N' methylenebisacrylamide (BIS), the accelerator N,N,N , N tetramethyl ethylenediamidne TMEDA, and potasium persulfate as initiator. Equilibrium swelling properties of hydrogels were studied in pH 2.2-8 range and temperature 10-45degree; LCST and pH critic point of the IPN's were determined; the composition of the interpenetrating network was measured by elemental analysis, and the morphological structure characterized by SEM. The volume of the cells of PAAC hydrogels decreased with increase in radiation dose, their mechanic hardness increased and they lost elasticity. The interpenetrating networks of samples with PAAc irradiated

  13. Pop-Cola Acids and Tooth Erosion: An In Vitro, In Vivo, Electron-Microscopic, and Clinical Report

    Directory of Open Access Journals (Sweden)

    Amirfirooz Borjian

    2010-01-01

    Full Text Available Introduction. Manufactured Colas are consumed universally as soft drinks. Evidence about the acid contents of Cola-beverages and its effects on teeth is rare. Aim. To assess (i cola acidity and buffering capacity in vitro, (ii tooth erosion after swishing with colas in vivo (iii scanning electron microscopic effects on teeth of colas, and tooth-brush abrasion, and (iv report a clinical case of erosion from cola consumption. Materials and Methods. (i We measured six commercially available pop “Cola beverages”, pH, and buffering capacities using a pH-Mettler Automatic Titrator, with weak solution of Sodium Hydroxide (ii two cohorts, one with teeth, the second without teeth rinsed with aliquots of Cola for 60 seconds. Swished cola samples tested for calcium and phosphorus contents using standardized chemical analytical methods (iii enamel, dentine, and the enamel-cemental junction from unerupted extracted wisdom teeth were examined with a scanning electron microscope after exposure to colas, and tested for tooth-brush abrasion; (iv a clinical case of pop cola erosion presentation, are all described. Results. Comparisons among pop colas tested in vitro reveal high acidity with very low pH. Buffering capacities in millilitres of 0.5 M NaOH needed to increase one pH unit, to pH 5.5 and pH 7 are reported. Rinsing in vivo with pop cola causes leeching of calcium from teeth; SEM shows dental erosion, and pop-cola consumption induces advanced dental erosion and facilitates abrasion. Conclusions. (i Pop-Cola acid activity is below the critical pH 5.5 for tooth dissolution, with high buffering capacities countering neutralization effects of saliva; (ii calcium is leeched out of teeth after rinsing with pop colas; (iii SEM evidence explains why chronic exposure to acid pop colas causes dental frangibles; (iv a clinical case of pop-cola erosion confirms this.

  14. Pop-cola acids and tooth erosion: an in vitro, in vivo, electron-microscopic, and clinical report.

    Science.gov (United States)

    Borjian, Amirfirooz; Ferrari, Claudia C F; Anouf, Antoni; Touyz, Louis Z G

    2010-01-01

    Introduction. Manufactured Colas are consumed universally as soft drinks. Evidence about the acid contents of Cola-beverages and its effects on teeth is rare. Aim. To assess (i) cola acidity and buffering capacity in vitro, (ii) tooth erosion after swishing with colas in vivo (iii) scanning electron microscopic effects on teeth of colas, and tooth-brush abrasion, and (iv) report a clinical case of erosion from cola consumption. Materials and Methods. (i) We measured six commercially available pop "Cola beverages", pH, and buffering capacities using a pH-Mettler Automatic Titrator, with weak solution of Sodium Hydroxide (ii) two cohorts, one with teeth, the second without teeth rinsed with aliquots of Cola for 60 seconds. Swished cola samples tested for calcium and phosphorus contents using standardized chemical analytical methods (iii) enamel, dentine, and the enamel-cemental junction from unerupted extracted wisdom teeth were examined with a scanning electron microscope after exposure to colas, and tested for tooth-brush abrasion; (iv) a clinical case of pop cola erosion presentation, are all described. Results. Comparisons among pop colas tested in vitro reveal high acidity with very low pH. Buffering capacities in millilitres of 0.5 M NaOH needed to increase one pH unit, to pH 5.5 and pH 7 are reported. Rinsing in vivo with pop cola causes leeching of calcium from teeth; SEM shows dental erosion, and pop-cola consumption induces advanced dental erosion and facilitates abrasion. Conclusions. (i) Pop-Cola acid activity is below the critical pH 5.5 for tooth dissolution, with high buffering capacities countering neutralization effects of saliva; (ii) calcium is leeched out of teeth after rinsing with pop colas; (iii) SEM evidence explains why chronic exposure to acid pop colas causes dental frangibles; (iv) a clinical case of pop-cola erosion confirms this.

  15. Comparative analysis of endodontic smear layer removal efficacy of 17% ethylenediaminetetraacetic acid, 7% maleic acid, and 2% chlorhexidine using scanning electron microscope: An in vitro study.

    Science.gov (United States)

    Attur, Kailash; Joy, Mathew T; Karim, Riyas; Anil Kumar, V J; Deepika, C; Ahmed, Haseena

    2016-08-01

    The aim of the present study was to evaluate the efficiency of different endodontic irrigants in the removal of smear layer through scanning electron microscopic image analysis. The present in vitro study was carried out on 45 single-rooted extracted human mandibular premolar teeth with single canal and complete root formation. Teeth were randomly assigned to three groups with 15 teeth in each group. Group I samples were irrigated with 17% ethylenediaminetetraacetic (EDTA) irrigation, Group II with 7% maleic acid irrigation, and Group III with 2% chlorhexidine irrigation. Scanning electron microscope evaluation was done for the assessment of smear layer removal in the coronal, middle, and apical thirds. Comparison of the smear layer removal between the three different groups was done by Kruskal-Wallis test, followed by Mann-Whitney U test for comparing individual groups. A P value less than 0.05 was considered to be statistically significant. Statistically significant difference was seen between the two test groups (17% EDTA vs. 7% maleic acid and 17% EDTA vs. 2% chlorhexidine) in smear layer removal at coronal, middle, and apical thirds of the root canal. The most efficient smear layer removal was seen in Group I with 17% EDTA irrigation compared with other groups (P < 0.05) and the least by 2% chlorhexidine. The present study shows that 17% EDTA efficiently removes the smear layer from root canal walls.

  16. Study of the electronic structure at the interface between fluorene-1-carboxylic acid molecules and Cu(110)

    International Nuclear Information System (INIS)

    Song Fei; Mao Hongying; Guan Dandan; Dou Weidong; Zhang Hanjie; Li Haiyang; He Pimo; Bao Shining; Hofmann, Philip

    2009-01-01

    The interface electronic properties of fluorene-1-carboxylic acid (FC-1) adsorbed on Cu(110) have been studied by ultraviolet photoemission spectroscopy (UPS) and first-principles calculations. Both the molecular orbitals and the Cu valence band are significantly modified upon adsorption. FC-1 is chemically bonded to Cu(110) through charge donation and back donation involving the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) of the molecule. An observed reduction of the work function can be attributed to the adsorption induced charge redistribution, and the positive interface dipole.

  17. Abscisic (ABA)-aldehyde is a precursor to, and 1 prime ,4 prime -trans-ABA-diol a catabolite of, ABA in apple. [Malus domestica

    Energy Technology Data Exchange (ETDEWEB)

    Rock, C.D.; Zeevaart, J.A.D. (Michigan State Univ., East Lansing (USA))

    1990-07-01

    Previous {sup 18}O labeling studies of abscisic acid (ABA) have shown that apple (Malus domestica Borkh. cv Granny Smith) fruits synthesize a majority of ({sup 18}O)ABA with the label incorporated in the 1{prime}-hydroxyl position and unlabeled in the carboxyl group (JAD Zeevaart, TG Heath, DA Gage (1989) Plant Physiol 91: 1594-1601). It was proposed that exchange of {sup 18}O in the side chain with the medium occurred at an aldehyde intermediate stage of ABA biosynthesis. We have isolated ABA-aldehyde and 1{prime}-4{prime}-trans-ABA-diol (ABA-trans-diol) from {sup 18}O-labeled apple fruit tissue and measured the extent and position of {sup 18}O incorporation by tandem mass spectrometry. {sup 18}O-Labeling patterns of ABA-aldehyde, ABA-trans-diol, and ABA indicate that ABA-aldehyde is a precursor to, and ABA-trans-diol a catabolite of, ABA. Exchange of {sup 18}O in the carbonyl of ABA-aldehyde can be the cause of loss of {sup 18}O from the side chain of ({sup 18}O)ABA. Results of feeding experiments with deuterated substrates provide further support for the precursor-product relationship of ABA-aldehyde {yields} ABA {yields} ABA-trans-diol. The ABA-aldehyde and ABA-trans-diol contents of fruits and leaves were low, approximately 1 and 0.02 nanograms per gram fresh weight for ABA-aldehyde and ABA-trans-diol, respectively, while ABA levels in fruits ranged from 10 to 200 nanograms per gram fresh weight. ABA biosynthesis was about 10-fold lower in fruits than in leaves. In fruits, the majority of ABA was conjugated to {beta}-D-glucopyranosyl abscisate, whereas in leaves ABA was mainly hydroxylated to phaseic acid. Parallel pathways for ABA and trans-ABA biosynthesis and conjugation in fruits and leaves are proposed.

  18. R-matrix calculation of low-energy electron collisions with phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Bryjko, Lilianna; Van Mourik, Tanja [School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST (United Kingdom); Dora, Amar; Tennyson, Jonathan, E-mail: j.tennyson@ucl.ac.u [Department of Physics and Astronomy, University College London, Gower St, London WC1E 6BT (United Kingdom)

    2010-12-14

    Electron collision calculations are performed on two conformers of H{sub 3}PO{sub 4}, a weakly dipolar form with all OH groups pointing up and a strongly dipolar form where one OH group points down. Strong evidence is found for a broad shape resonance at about 7 eV for both conformers, although the precise parameters of this resonance are sensitive to the details of the target wavefunction used. Ten-state close-coupling calculations suggest the presence of very narrow Feshbach resonances in a similar energy region. Again both conformers behave similarly. Elastic and electronically inelastic cross sections are calculated for both conformers.

  19. Absence of cell communication for fluorescein and dansylated amino acids in an electronic coupled cell system

    NARCIS (Netherlands)

    Venrooij, G.E.P.M. van; Hax, W.M.A.; Schouten, V.J.A.; Denier van der Gon, J.J.; Vorst, H.A. van der

    1975-01-01

    Quantitative evaluation of the diffusion process of sodium fluorescein and dansylated amino acids in the salivary gland of the larvae of Drosophila hydei reveals that the differences in specific permeability between the junctional and nonjunctional membranes, as found for small ions, do not apply to

  20. Transmission electron microscopic analysis showing structural changes to bacterial cells treated with electrolyzed water and an acidic sanitizer.

    Science.gov (United States)

    Feliciano, Lizanel; Lee, Jaesung; Pascall, Melvin A

    2012-04-01

    The effects of various sanitizers on the viability and cellular injury to structures of Escherichia coli and Listeria innocua were investigated. A food grade organic acidic formulation (pH 2.5) and acidic, neutral, and basic electrolyzed water [AEW (pH 2.7, oxidation reduction potential; ORP: 1100 mV, free available chlorine; FAC: 150 ppm), NEW (pH 6.9, ORP: 840 mV, FAC: 150 ppm), BEW (pH 11.6, ORP: -810 mV)] were used to treat E. coli and L. innocua cells. After 10 min of exposure to the sanitizers, changes to the bacterial numbers and cell structures were evaluated by plate counting and transmission electron microscopy (TEM), respectively. It was concluded from the results that the sanitizers reduced the E. coli cells between 2 and 3 log CFU/mL. Except for the BEW treatment, reductions in L. innocua population were greater (>1 log CFU/mL) than that of E. coli for all treatments. Data from the TEM showed that all sanitizers caused changes to the cell envelope and cytoplasm of both organisms. However, smaller changes were observed for L. innocua cells. Decrease in the integrity of the cell envelope and aggregation of the cytoplasmic components appeared to be mainly because of exposure to the sanitizers. The organic acid formulation and AEW were the most effective sanitizers against bacterial cells, indicating that penetration of acidic substances effectively caused the cell inactivation. An understanding of the method in which E-water and an acidic sanitizer cause injury to E. coli and L. innocua would be helpful in selecting an effective chemical agent as a food safety tool. This will allow a scientist to target similar microorganisms such as food borne bacteria with structures that are vulnerable to the sanitizer. © 2012 Institute of Food Technologists®

  1. Electron donation characteristics and interplays of major volatile fatty acids from anaerobically fermented organic matters in bioelectrochemical systems.

    Science.gov (United States)

    Zhang, Zhiqiang; Li, Jiamiao; Hao, Xiaoxuan; Gu, Zaoli; Xia, Siqing

    2018-02-23

    Anaerobic fermentation liquid of waste organic matters (WOMs) is rich in volatile fatty acids (VFAs), which can be treated with bioelectrochemical systems for both electrical energy recovery and organics removal. In this work, four major VFAs in the fermented WOMs supernatant were selected to examine their electron donation characteristics for power output and their complicated interplays in microbial fuel cells (MFCs). Results indicated a priority sequence of acetate, propionate, n-butyrate and i-valerate when served as the sole electron donor for electricity generation. The MFC solely fed with acetate showed the highest coulombic efficiency and power density, and the longest period for electricity production. When two of the VFAs were added with equal proportion, both acids contributed positively to electricity generation, while the selective or competitive use of substrates by diverse microorganisms behaved as an antagonism effect to prolong the degradation time of each VFA. When acetate and propionate, the preferable substrates for electricity generation, were mixed in various proportions, their large concentration difference led to improved electrical performance but decreased organic removal rate.

  2. Use of 3-(4-hydroxyphenyl)propionic acid as electron donating compound in a potentiometric aflatoxin M1-immunosensor

    International Nuclear Information System (INIS)

    Rameil, Steffen; Schubert, Peter; Grundmann, Peter; Dietrich, Richard; Maertlbauer, Erwin

    2010-01-01

    We developed a potentiometric aflatoxin M 1 -immunosensor which utilizes 3-(4-hydroxyphenyl)propionic acid (p-HPPA) as electron donating compound for horseradish peroxidase (HRP; EC 1.11.1.7). The assay system consists of a polypyrrole-surface-working electrode coated with a polyclonal anti-M 1 antibody (pAb-AFM 1 ), a Ag/AgCl reference electrode and a HRP-aflatoxin B 1 conjugate (HRP-AFB 1 conjugate). To optimize the potentiometric measuring system p-HPPA as well as related compounds serving as electron donating compounds were compared. Also the influence of different buffer systems, varying pH and substrate concentrations on signal intensity was investigated. Our results suggest that reaction conditions that favor the formation of Pummerer's type ketones lead to an increase in signal intensity rather than formation of fluorescent dye. Comparison with commercial ready-to-use HRP electron donating compounds such as 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), o-phenylenediamine (OPD) or 3,3',5,5'-tetramethylbenzidine (TMB) showed that only 34%, 77% and 49% of the signal intensity of p-HPPA were reached, respectively. The optimized assay had a detection limit of 40 pg mL -1 and allowed detection of 500 pg mL -1 (FDA action limit) aflatoxin M 1 (AFM 1 ) in pasteurized milk and UHT-milk containing 0.3-3.8% fat within 10 min without any sample treatment. The working range was between 250 and 2000 pg mL -1 AFM 1 .

  3. A kinetic study of plutonium dioxide dissolution in hydrochloric acid using iron (II) as an electron transfer catalyst

    International Nuclear Information System (INIS)

    Fife, K.W.

    1996-09-01

    Effective dissolution of plutonium dioxide has traditionally been accomplished by contact with strong nitric acid containing a small amount of fluoride at temperatures of ∼ 100 C. In spite of these aggressive conditions, PuO 2 dissolution is sometimes incomplete requiring additional contact with the solvent. This work focused on an alternative to conventional dissolution in nitric acid where an electron transfer catalyst, Fe(II), was used in hydrochloric acid. Cyclic voltammetry was employed as an in-situ analytical technique for monitoring the dissolution reaction rate. The plutonium oxide selected for this study was decomposed plutonium oxalate with > 95% of the material having a particle diameter (< 70 microm) as determined by a scanning laser microscopy technique. Attempts to dry sieve the oxide into narrow size fractions prior to dissolution in the HCl-Fe(II) solvent system failed, apparently due to significant interparticle attractive forces. Although sieve splits were obtained, subsequent scanning laser microscopy analysis of the sieve fractions indicated that particle segregation was not accomplished and the individual sieve fractions retained a particle size distribution very similar to the original powder assemblage. This phenomena was confirmed through subsequent dissolution experiments on the various screen fractions which illustrated no difference in kinetic behavior between the original oxide assemblage and the sieve fractions

  4. Roles of abscisic acid and auxin in shoot-supplied ammonium inhibition of root system development.

    Science.gov (United States)

    Li, Baohai; Li, Qing; Kronzucker, Herbert J; Shi, Weiming

    2011-10-01

    A plastic root system is a prerequisite for successful plant acclimation to variable environments. The normally functioning root system is the result of a complex interaction of root-borne signals and shoot-derived regulators. We recently demonstrated that AUX1, a well-studied component of auxin transport, mediates shoot-supplied ammonium (SSA) inhibition of lateral root (LR) formation in Arabidopsis. By contrast, the response did not involve ABA pathways, via which several other abiotic stresses affect LR formation. We proposed that SSA regulates LR emergence by interrupting AUX1-mediated auxin transport from shoot to root. Here, by analyzing both ABA- and auxin-related mutants, we show that AUX1 is also required for SSA-mediated suppression of primary root growth. Ammonium content in shoots was furthermore shown to increase linearly with shoot-, but not root-supplied, ammonium, suggesting it may represent the internal trigger for SSA inhibition of root development. Taken together, our data identify AUX1-mediated auxin transport as a key transmission step in the sensing of excessive ammonium exposure and its inhibitory effect on root development. 

  5. Roles of abscisic acid and auxin in shoot-supplied ammonium inhibition of root system development

    OpenAIRE

    Li, Baohai; Li, Qing; Kronzucker, Herbert J; Shi, Weiming

    2011-01-01

    A plastic root system is a prerequisite for successful plant acclimation to variable environments. The normally functioning root system is the result of a complex interaction of root-borne signals and shoot-derived regulators. We recently demonstrated that AUX1, a well-studied component of auxin transport, mediates shoot-supplied ammonium (SSA) inhibition of lateral root (LR) formation in Arabidopsis. By contrast, the response did not involve ABA pathways, via which several other abiotic stre...

  6. An ancestral role for CONSTITUTIVE TRIPLE RESPONSE1 proteins in both ethylene and abscisic acid signaling

    NARCIS (Netherlands)

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

    2015-01-01

    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

  7. Interaction of Cytokinins and Abscisic Acid During Regulation of Stomatal Opening in Bean Leaves

    Czech Academy of Sciences Publication Activity Database

    Pospíšilová, Jana

    2003-01-01

    Roč. 41, č. 1 (2003), s. 49-56 ISSN 0300-3604 R&D Projects: GA ČR GA522/02/1099 Institutional research plan: CEZ:AV0Z5038910 Keywords : benzyladenine * net photosynthetic rate * Phaseolus vulgaris Subject RIV: EF - Botanics Impact factor: 0.661, year: 2003

  8. Stomatal and non-stomatal effects of exogenous abscisic acid during plant hardening

    Czech Academy of Sciences Publication Activity Database

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

    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 : phytohormones * micropropagation * photosynthesis Subject RIV: ED - Physiology Impact factor: 2.334, year: 2008

  9. Dynamic subnuclear relocalisation of WRKY40 in response to Abscisic acid in Arabidopsis thaliana.

    Science.gov (United States)

    Geilen, Katja; Böhmer, Maik

    2015-08-21

    WRKY18, WRKY40 and WRKY60 are members of the WRKY transcription factor family and function as transcriptional regulators in ABA signal transduction in Arabidopsis thaliana. Here we show that WRKY18 and WRKY40, but not WRKY60, co-localise with PIF3, PIF4 and PHYB to Phytochrome B-containing nuclear bodies (PNBs). Localisation to the PNBs is phosphorylation-dependent and is inhibited by the general Ser/Thr-kinase inhibitor Staurosporine. Upon ABA treatment, WRKY40 relocalises from PNBs to the nucleoplasm in an OST1-dependent manner. This stimulus-induced relocalisation was not observed in response to other abiotic or biotic stimuli, including NaCl, MeJA or flg22 treatment. Bimolecular fluorescence complementation experiments indicate that while PIF3, PIF4 and PHYB physically interact in these bodies, PHYB, PIF3 and PIF4 do not interact with the two WRKY transcription factors, which may suggest a more general role for these bodies in regulation of transcriptional activity.

  10. Dynamic subnuclear relocalisation of WRKY40 in response to Abscisic acid in Arabidopsis thaliana

    OpenAIRE

    Geilen, Katja; B?hmer, Maik

    2015-01-01

    WRKY18, WRKY40 and WRKY60 are members of the WRKY transcription factor family and function as transcriptional regulators in ABA signal transduction in Arabidopsis thaliana. Here we show that WRKY18 and WRKY40, but not WRKY60, co-localise with PIF3, PIF4 and PHYB to Phytochrome B-containing nuclear bodies (PNBs). Localisation to the PNBs is phosphorylation-dependent and is inhibited by the general Ser/Thr-kinase inhibitor Staurosporine. Upon ABA treatment, WRKY40 relocalises from PNBs to the n...

  11. Polyethylene glycol and abscisic acid improve maturation and regeneration of Panax ginseng somatic embryos

    Czech Academy of Sciences Publication Activity Database

    Langhansová, Lenka; Konrádová, H.; Vaněk, Tomáš

    2004-01-01

    Roč. 22, - (2004), s. 725-730 ISSN 0721-7714 R&D Projects: GA ČR GP521/02/P064; GA MŠk OC 843.10; GA MŠk ME 671 Institutional research plan: CEZ:AV0Z4055905 Keywords : ABA * Panax ginseng * somatic embryogenesis Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.457, year: 2004

  12. Isolation of a novel abscisic acid stress ripening ( OsASR ) gene ...

    African Journals Online (AJOL)

    The expression profile of OsASR obtained by the microarray analysis was confirmed by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) analysis of the gene. The two sets of data matched very well, suggesting that OsASR is a multiple stresses responsive gene in rice. Based on the sequence ...

  13. Copper suppresses abscisic acid catabolism and catalase activity, and inhibits seed germination of rice.

    Science.gov (United States)

    Ye, Nenghui; Li, Haoxuan; Zhu, Guohui; Liu, Yinggao; Liu, Rui; Xu, Weifeng; Jing, Yu; Peng, Xinxiang; Zhang, Jianhua

    2014-11-01

    Although copper (Cu) is an essential micronutrient for plants, a slight excess of Cu in soil can be harmful to plants. Unfortunately, Cu contamination is a growing problem all over the world due to human activities, and poses a soil stress to plant development. As one of the most important biological processes, seed germination is sensitive to Cu stress. However, little is known about the mechanism of Cu-induced inhibition of seed germination. In the present study, we investigated the relationship between Cu and ABA which is the predominant regulator of seed germination. Cu at a concentration of 30 µM effectively inhibited germination of rice caryopsis. ABA content in germinating seeds under copper stress was also higher than that under control conditions. Quantitative real-time PCR (qRT-PCR) revealed that Cu treatment reduced the expression of OsABA8ox2, a key gene of ABA catabolism in rice seeds. In addition, both malondialdehyde (MDA) and H2O2 contents were increased by Cu stress in the germinating seeds. Antioxidant enzyme assays revealed that only catalase activity was reduced by excess Cu, which was consistent with the mRNA profile of OsCATa during seed germination under Cu stress. Together, our results demonstrate that suppression of ABA catabolism and catalase (CAT) activity by excess Cu leads to the inhibition of seed germination of rice. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  14. Regulation of seed dormancy by abscisic acid and DELAY OF Germination 1

    NARCIS (Netherlands)

    Dekkers, S.J.W.; Bentsink, L.

    2015-01-01

    Physiological dormancy has been described as a physiological inhibiting mechanism that prevents radicle emergence. It can be caused by the embryo (embryo dormancy) as well as by the structures that cover the embryo. One of its functions is to time plant growth and reproduction to the most optimal

  15. Isolation of a novel abscisic acid stress ripening (OsASR) gene from ...

    African Journals Online (AJOL)

    user

    2012-09-13

    Sep 13, 2012 ... but surprisingly these genes are not present in. Arabidopsis (Carrari et al., 2004). The expression patterns of the ASR gene family members vary among different species during plant development and abiotic stresses (Maskin et al., 2001). Tomato ASR1 protein is localized in both the nucleus and the cytosol ...

  16. Abscisic acid has a key role in modulating diverse plant-pathogen interactions

    Science.gov (United States)

    Jun Fan; Lionel Hill; Casey Crooks; Peter Doerner; Chris Lamb

    2009-01-01

    We isolated an activation-tagged Arabidopsis (Arabidopsis thaliana) line, constitutive disease susceptibility2-1D (cds2-1D), that showed enhanced bacterial growth when challenged with various Pseudomonas syringae strains. Systemic acquired resistance and systemic PATHOGENESIS-RELATED GENE1 induction were also compromised in cds2-1D. The T-DNA insertion adjacent to NINE...

  17. Gibberellin-Abscisic Acid Balances during Arbuscular Mycorrhiza Formation in Tomato

    Czech Academy of Sciences Publication Activity Database

    Martin-Rodriguez, J.A.; Huertas, R.; Ho-Plagaro, T.; Ocampo, J.A.; Turečková, Veronika; Tarkowská, Danuše; Ludwig-Mueller, J.; Garcia-Garrido, J.M.

    2016-01-01

    Roč. 7, AUG 23 (2016), s. 1273 ISSN 1664-462X R&D Projects: GA ČR GA14-34792S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : arbuscular mycorrhiza * plant hormones * gibberellins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.298, year: 2016

  18. The effect of drought stress and exogenous abscisic acid on growth ...

    African Journals Online (AJOL)

    ABA) on growth, protein content and antioxidative enzyme activity in leaves, roots and corms of Crocus sativus L. A comparative study of sample and control showed that leaf relative water content (RWC), length and number of leaves decreased ...

  19. Sequencing and transcriptional analysis of the biosynthesis gene cluster of abscisic acid-producing Botrytis cinerea.

    Science.gov (United States)

    Gong, Tao; Shu, Dan; Yang, Jie; Ding, Zhong-Tao; Tan, Hong

    2014-09-29

    Botrytis cinerea is a model species with great importance as a pathogen of plants and has become used for biotechnological production of ABA. The ABA cluster of B. cinerea is composed of an open reading frame without significant similarities (bcaba3), followed by the genes (bcaba1 and bcaba2) encoding P450 monooxygenases and a gene probably coding for a short-chain dehydrogenase/reductase (bcaba4). In B. cinerea ATCC58025, targeted inactivation of the genes in the cluster suggested at least three genes responsible for the hydroxylation at carbon atom C-1' and C-4' or oxidation at C-4' of ABA. Our group has identified an ABA-overproducing strain, B. cinerea TB-3-H8. To differentiate TB-3-H8 from other B. cinerea strains with the functional ABA cluster, the DNA sequence of the 12.11-kb region containing the cluster of B. cinerea TB-3-H8 was determined. Full-length cDNAs were also isolated for bcaba1, bcaba2, bcaba3 and bcaba4 from B. cinerea TB-3-H8. Sequence comparison of the four genes and their flanking regions respectively derived from B. cinerea TB-3-H8, B05.10 and T4 revealed that major variations were located in intergenic sequences. In B. cinerea TB-3-H8, the expression profiles of the four function genes under ABA high-yield conditions were also analyzed by real-time PCR.

  20. Crucial roles of abscisic acid biogenesis in virulence of rice blast fungus Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Carla eSpence

    2015-12-01

    Full Text Available 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 JA- and ETH-mediated ISR. ABA acts antagonistically towards SA, JA, and ETH signaling, to impede plant defense responses. EA105 may be reducing the virulence of M. oryzae by preventing the pathogen from up-regulating the key ABA biosynthetic gene NCED3 in rice roots, as well as a β-glucosidase likely involved in activating conjugated inactive forms of ABA. However, changes in total ABA concentrations were not apparent, provoking the question of whether ABA concentration is an indicator of ABA signaling and response. In the rice-M. oryzae interaction, ABA plays a dual role in disease severity by increasing plant susceptibility and accelerating pathogenesis in the fungus itself. ABA is biosynthesized by M. oryzae. Further, exogenous ABA increased spore germination and appressoria formation, distinct from other plant growth regulators. EA105, which inhibits appressoria formation, counteracted the virulence-promoting effects of ABA on M. oryzae. The role of endogenous fungal ABA in blast disease was confirmed through the inability of a knockout mutant impaired in ABA biosynthesis to form lesions on rice. Therefore, it appears that EA105 is invoking multiple strategies in its protection of rice from blast including direct mechanisms as well as those mediated through plant signaling. ABA is a molecule that is likely implicated in both tactics.

  1. Abscisic acid and hypoxic induction of anoxia tolerance in roots of lettuce seedlings.

    Science.gov (United States)

    Kato-Noguchi, H

    2000-11-01

    Lettuce (Lactuca sativa L.) seedlings were subjected to anoxic stress after ABA-pretreatment (ABA-PT) or hypoxic-pretreatment (H-PT). The H-PT increased the survivability of the anoxia in roots of the seedlings by 5.2-fold compared to that of non-pretreated (N-PT) seedlings. ABA-PT also increased the survivability at concentrations greater than 1 microM, and the survivability increased with increasing ABA doses. At 100 microM ABA, the survivability was 4.5-fold greater than that of N-PT seedlings. During pretreatment periods, alcohol dehydrogenase (ADH, EC 1.1.1.1) activity in the roots became 3.1- and 3.4-fold greater than that of N-PT seedlings following 100 microM ABA-PT and H-PT seedlings, respectively. After the onset of anoxic stress, ADH activities in all roots increased, but the activities in H-PT and ABA-PT roots remained much greater than that in N-PT roots, and the average ethanol production rate for the initial 6 h was 5.3, 4.0 and 1.4 micromol g(-1) FW h(-1) for H-PT, ABA-PT and N-PT roots, respectively. Roots of the seedlings lost ATP rapidly under anoxic stress; however, the decrease in ATP was much slower in the ABA-PT and H-PT seedlings than in the N-PT seedlings. These results suggest that the ABA-PT and H-PT may maintain ATP levels due to activation of ethanolic fermentation, which may be one of the causes of the increasing anoxia tolerance in the seedling roots. Measurement of endogenous ABA levels, however, showed that ABA levels did not increase during the H-PT, suggesting that the H-PT does not increase tolerance through an increase in ABA levels.

  2. Abscisic Acid-Cytokinin Antagonism Modulates Resistance Against Pseudomonas syringae in Tobacco

    Czech Academy of Sciences Publication Activity Database

    Grosskinsky, D. K.; van der Graaff, E.; Roitsch, Thomas

    2015-01-01

    Roč. 104, č. 12 (2015), s. 1283-1288 ISSN 0031-949X Institutional support: RVO:67179843 Keywords : Nicotiana tabacum * plant-pathogen interaction Subject RIV: EH - Ecology, Behaviour Impact factor: 3.011, year: 2015

  3. Abscisic Acid Represses Growth of the Arabidopsis Embryonic Axis after Germination by Enhancing Auxin Signaling

    Czech Academy of Sciences Publication Activity Database

    Belin, Ch.; Megies, Ch.; Hauserová, Eva; Lopez-Molina, L.

    2009-01-01

    Roč. 21, č. 8 (2009), s. 2253-2268 ISSN 1040-4651 Institutional research plan: CEZ:AV0Z50380511 Keywords : SEED-GERMINATION * HYPOCOTYL ELONGATION * ROOT GRAVITROPISM Subject RIV: ED - Physiology Impact factor: 9.293, year: 2009

  4. Guard Cell Signal Transduction Network: Advances in Understanding Abscisic Acid, CO2, and Ca2+ Signaling

    KAUST Repository

    Kim, Tae-Houn

    2010-05-04

    Stomatal pores are formed by pairs of specialized epidermal guard cells and serve as major gateways for both CO2 influx into plants from the atmosphere and transpirational water loss of plants. Because they regulate stomatal pore apertures via integration of both endogenous hormonal stimuli and environmental signals, guard cells have been highly developed as a model system to dissect the dynamics and mechanisms of plant-cell signaling. The stress hormone ABA and elevated levels of CO2 activate complex signaling pathways in guard cells that are mediated by kinases/phosphatases, secondary messengers, and ion channel regulation. Recent research in guard cells has led to a new hypothesis for how plants achieve specificity in intracellular calcium signaling: CO2 and ABA enhance (prime) the calcium sensitivity of downstream calcium-signaling mechanisms. Recent progress in identification of early stomatal signaling components are reviewed here, including ABA receptors and CO2-binding response proteins, as well as systems approaches that advance our understanding of guard cell-signaling mechanisms.

  5. Abscisic acid dynamics in roots detected with genetically encoded FRET sensors.

    Science.gov (United States)

    Jones, Alexander M; Danielson, Jonas Ah; Manojkumar, Shruti N; Lanquar, Viviane; Grossmann, Guido; Frommer, Wolf B

    2014-04-15

    Cytosolic hormone levels must be tightly controlled at the level of influx, efflux, synthesis, degradation and compartmentation. To determine ABA dynamics at the single cell level, FRET sensors (ABACUS) covering a range ∼0.2-800 µM were engineered using structure-guided design and a high-throughput screening platform. When expressed in yeast, ABACUS1 detected concentrative ABA uptake mediated by the AIT1/NRT1.2 transporter. Arabidopsis roots expressing ABACUS1-2µ (Kd∼2 µM) and ABACUS1-80µ (Kd∼80 µM) respond to perfusion with ABA in a concentration-dependent manner. The properties of the observed ABA accumulation in roots appear incompatible with the activity of known ABA transporters (AIT1, ABCG40). ABACUS reveals effects of external ABA on homeostasis, that is, ABA-triggered induction of ABA degradation, modification, or compartmentation. ABACUS can be used to study ABA responses in mutants and quantitatively monitor ABA translocation and regulation, and identify missing components. The sensor screening platform promises to enable rapid fine-tuning of the ABA sensors and engineering of plant and animal hormone sensors to advance our understanding of hormone signaling. DOI: http://dx.doi.org/10.7554/eLife.01741.001.

  6. Effect of abscisic acid on photosynthetic parameters during ex vitro transfer of micropropagated tobacco plantlets

    Czech Academy of Sciences Publication Activity Database

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

    2009-01-01

    Roč. 53, č. 1 (2009), s. 11-20 ISSN 0006-3134 R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : carotenoids * chlorophyll contents * chlorophyll fluorescence Subject RIV: ED - Physiology Impact factor: 1.656, year: 2009

  7. Casein kinase 1-Like 3 is required for abscisic acid regulation of ...

    African Journals Online (AJOL)

    Jane

    2011-10-10

    Oct 10, 2011 ... different cell types and in several subcellular compart- ments, including the membranes, nucleus and cytoplasm ... priming by another kinase. CKI also phosphorylates a related unprimed site, which ... CK1 isoforms function as regulators of multiple signal transduction pathways in most eukaryotic cell types.

  8. Casein kinase 1-Like 3 is required for abscisic acid regulation of ...

    African Journals Online (AJOL)

    Jane

    2011-10-10

    Oct 10, 2011 ... threonine protein kinases is found in eukaryotic organisms from yeast to humans. Mammals ... numbers SALK_016571c, and it was named ckl3 in the present study. Columbia-0 ecotype Arabidopsis was ... measuring root growth six days after the transfer of 6-day old seedlings onto vertical Murashige and ...

  9. Involvement of Arabidopsis RACK1 in Protein Translation and Its Regulation by Abscisic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianjun [University of British Columbia, Vancouver; Wang, Shucai [University of British Columbia, Vancouver; Valerius, Oliver [Universitaet Goettingen, Goettingen, Germany; Hall, Hardy [University of British Columbia, Vancouver; Zeng, Qingning [University of British Columbia, Vancouver; Li, Jian-Feng [Harvard University; Weston, David [ORNL; Ellis, Brian [University of British Columbia, Vancouver; Chen, Jay [ORNL

    2011-01-01

    Earlier studies have shown that RACK1 functions as a negative regulator of ABA responses in Arabidopsis, but the molecular mechanism of the action of RACK1 in these processes remains elusive. Global gene expression profiling revealed that approximately 40% of the genes affected by ABA treatment were affected in a similar manner by the rack1 mutation, supporting the view that RACK1 is an important regulator of ABA responses. On the other hand, co-expression analysis revealed that >80% of the genes co-expressed with RACK1 encode ribosome proteins, implying a close relationship between RACK1 s function and the ribosome complex. These results implied that the regulatory role for RACK1 in ABA responses may be partially due to its putative function in protein translation, which is one of the major cellular processes that mammalian and yeast RACK1 is involved in. Consistently, all three Arabidopsis RACK1 homologous genes, namely RACK1A, RACK1B and RACK1C, complemented the growth defects of the S. cerevisiae cpc2/rack1 mutant. In addition, RACK1 physically interacts with Arabidopsis Eukaryotic Initiation Factor 6 (eIF6), whose mammalian homologue is a key regulator of 80S ribosome assembly. Moreover, rack1 mutants displayed hypersensitivity to anisomycin, an inhibitor of protein translation, and displayed characteristics of impaired 80S functional ribosome assembly and 60S ribosomal subunit biogenesis in a ribosome profiling assay. Gene expression analysis revealed that ABA inhibits the expression of both RACK1 and eIF6. Taken together, these results suggest that RACK1 may be required for normal production of 60S and 80S ribosomes and that its action in these processes may be regulated by ABA.

  10. Effects of cadmium exposure on phytochelatin and the synthesis of abscisic acid in funalia trogii

    Energy Technology Data Exchange (ETDEWEB)

    Yuerekli, F.; Porgali, Z.B. [Inonu University, Arts and Science Faculty, Department of Biology, 44069 Malatya (Turkey); Uenyayar, A.; Mazmanci, M.A. [Mersin University, Engineering Faculty, Engineering Faculty, 33000 Mersin (Turkey)

    2004-08-01

    Heavy metal toxicity poses major environmental and health problems as heavy metals are more difficult to remediate than chemical contaminants, which can be degraded by microorganisms. Phytochelatins are formed in plants and some fungi upon exposure to a range of different heavy metals. Fungi show sensitivity to many environmental factors, including nutrient limitation, changes in carbon sources and heavy metal exposure. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  11. Overexpression of OsWRKY72 gene interferes in the abscisic acid ...

    Indian Academy of Sciences (India)

    Prakash

    to mannitol, NaCl, ABA stresses and sugar starvation than vector plants. .... PCR was run for. 24–28 cycles using the AtActin2 gene as an internal standard, and each RT-PCR reaction was repeated three times. 3. Results. 3.1 Ectopic expression of the OsWRKY72 ... of the transgenic seeds did not germinate (figure 2A).

  12. Characterization and Antimicrobial Property of Poly(Acrylic Acid Nanogel Containing Silver Particle Prepared by Electron Beam

    Directory of Open Access Journals (Sweden)

    Jong-Bae Choi

    2013-05-01

    Full Text Available In this study, we developed a one step process to synthesize nanogel containing silver nanoparticles involving electron beam irradiation. Water-soluble silver nitrate powder is dissolved in the distilled water and then poly(acrylic acid (PAAc and hexane are put into this silver nitrate solution. These samples are irradiated by an electron beam to make the PAAc nanogels containing silver nanoparticles (Ag/PAAc nanogels. The nanoparticles were characterized by scanning electron microscopy (SEM and energy dispersive spectroscopy (EDS. In addition, the particle size and zeta-potential were confirmed by a particle size analyzer (PSA. The antibacterial properties of the nanogels were evaluated by paper diffusion test. The Ag/PAAc nanogels had an antibacterial effect against Escherichia coli and Staphylococcus aureus. The nanogels also demonstrated a good healing effect against diabetic ulcer. The size of the Ag/PAAc nanogels decreased with increasing irradiation doses, and the absolute value of the zeta potential increased with increasing irradiation doses. Also, the Ag/PAAc nanogels exhibited good antibacterial activity against both Gram-negative and Gram-positive bacteria. In in vivo wound healing, the Ag/PAAc nanogels have a good healing effect.

  13. The reduction of structural iron in ferruginous smectite via the amino acid cysteine: Implications for an electron shuttling compound

    Science.gov (United States)

    Morrison, Keith D.; Bristow, Thomas F.; Kennedy, Martin J.

    2013-04-01

    Microbes can reduce the structural iron (Fe(III)str) in clay minerals thus providing a potentially important terminal electron acceptor in the oxidation of organic matter. Many of these microorganisms participate in dissimilatory metal reduction with Fe(III) serving as the terminal electron acceptor either through direct contact with mineral surfaces or by way of electron shuttling compounds. Here we provide evidence for the electron shuttling capability of the amino acid cysteine with a ferruginous dioctahedral smectite (SWa-1) using infrared spectroscopy, X-ray diffraction and quantitative assay of ferric and ferrous iron. Reactions to determine the electron exchange between cysteine and SWa-1 were performed in pH 8 adjusted oxygen free solutions. Fourier transform infrared spectroscopy (FTIR) performed on self-supporting clay films reveals that cysteine has the ability to reduce Fe(III)str, as shown by the decrease in the intensity of the AlFeOH and FeFeOH deformation and stretching bands resulting from decreased hydroxyl vibrations in the octahedral sheets. X-ray diffraction of the c-oriented SWa-1 reveals that cysteine intercalated into the d00l interlayer spaces. Quantitative iron assay indicates that the SWa-1 retains its structural iron upon reduction by cysteine and reoxidation. The increased interlayer spacing due to the intercalation of cysteine implies that this electron exchange is occurring from the basal surfaces of the smectite, as opposed to edge sites. When the SWa-1 was rinsed in dialysis tubing, the AlFeOH and FeFeOH vibrations reappear in FTIR spectra and the XRD patterns reveal that the cysteine no longer occupies interlayer sites. These results are consistent with partially reversible changes in clay mineral structure resulting from the reduction of Fe(III)str. They support the hypothesis that cysteine could serve as an electron shuttling compound used by microorganisms to gain access to structural iron in clay minerals and extends the range

  14. A recovery of gold from electronic scrap by mechanical separation, acid leaching and electrowinning

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, K.I.; Lee, J.C.; Lee, C.K.; Joo, K.H.; Yoon, J.K.; Kang, H.R.; Kim, Y.S.; Sohn, H.J.

    1995-12-31

    A series of processes to recover the gold from electronic scrap which contains initially about 200--600 ppm Au have been developed. First, mechanical beneficiation including shredding, crushing and screening was employed. Results showed that 99 percent of gold component leaves in the fraction of under 1 mm of crushed scrap and its concentration was enriched to about 800 ppm without incineration. The scrap was leached in 50% aqua regia solution and gold was dissolved completely at 60 C within 2 hours. Other valuable metals such as silver, copper, nickel and iron were also dissolved. This resulting solution was boiled to remove nitrous compounds in the leachate. Finally, a newly designed electrolyzer was tested to recover the gold metal. More than 99% of gold and silver were recovered within an hour in electrowinning process.

  15. A study on the swelling behavior of poly(acrylic acid) hydrogels obtained by electron beam crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Sheikh, N., E-mail: nasheikh@aeoi.org.i [Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of); Jalili, L. [Polymer group, Technology and Engineering Department, Yazd University, Yazd (Iran, Islamic Republic of); Anvari, F. [Radiation Applications Research School, Nuclear Science and Technology Research Institute, Yazd (Iran, Islamic Republic of)

    2010-06-15

    Poly(acrylic acid) (PAA) hydrogels were prepared by using electron beam (EB) crosslinking of PAA homopolymer from its aqueous solutions. The swelling behavior of the hydrogels was studied as a function of the concentration of PAA solution, radiation dose, pH of the swelling medium and swelling time. Also the environmental pH effect on the water diffusion mode into hydrogels was investigated. These hydrogels clearly showed pH-sensitive swelling behavior with Fickian type of diffusion in the stomach-like pH medium (pH 1.3) and non-Fickian type in the intestine-like pH medium (pH 6.8).

  16. Laboratory Investigation of the Growth and Crystal Structure of Nitric Acid Hydrates by Transmission Electron Microscopy (TEM)

    Science.gov (United States)

    Blake, David F.; Chang, Sherwood (Technical Monitor)

    1994-01-01

    A great deal of recent laboratory work has focussed on the characterization of the nitric acid hydrates, thought to be present in type I Polar Stratospheric Clouds (PSCs). Phase relationships and vapor pressure measurements (1-3) and infrared characterizations (4-5) have been made. However, the observed properties of crystalline solids (composition, melting point, vapor pressure, surface reactivity, thermodynamic stability, extent of solid solution with other components, etc.) are controlled by their crystal structure. The only means of unequivocal structural identification for crystalline solids is diffraction (using electrons, X-rays, neutrons, etc.). Other observed properties of crystalline solids, such as their infrared spectra, their vapor pressure as a function of temperature, etc. yield only indirect information about what phases are present, their relative proportions, or whether they are crystalline or amorphous.

  17. Theoretical Determination of One-Electron Oxidation Potentials for Nucleic Acid Bases.

    Science.gov (United States)

    Psciuk, Brian T; Lord, Richard L; Munk, Barbara H; Schlegel, H Bernhard

    2012-12-11

    The oxidation potentials for N-methyl substituted nucleic acid bases guanine, adenine, cytosine, thymine, uracil, xanthine, and 8-oxoguanine were computed using B3LYP and CBS-QB3 with the SMD solvation model. Acid-base and tautomeric equilibria present in aqueous solution were accounted for by combining standard redox potentials with calculated pKa and tautomerization energies to produce an ensemble averaged pH dependent potential. Gas phase free energies were computed using B3LYP/aug-cc-pVTZ//B3LYP/6-31+G(d,p) and CBS-QB3. Solvation free energies were computed at the SMD/B3LYP/6-31+G(d,p) level of theory. Compared to experimental results, calculations with the CBS-QB3 level of theory have a mean absolute error (MAE) of ca. 1 kcal/mol for the gas phase proton affinity/gas phase basicity and an MAE of ca. 0.04 eV for the adiabatic/vertical ionization potentials. The B3LYP calculations have a MAE of ∼2 kcal/mol for the proton affinity/gas phase basicity data but systematically underestimated ionization potentials by 0.14-0.21 eV. Solvent cavities for charged solute species were rescaled uniformly by fitting computed pKa data to experimentally measured pKa values. After solvent cavity scaling, the MAEs for computed pKa's compared to experimental results are 0.7 for B3LYP and 0.9 for CBS-QB3. In acetonitrile, the computed E°(XH(+•)/XH) redox potentials are systematically lower than experimentally measured potentials by 0.21 V for CBS-QB3 and 0.33 V for B3LYP. However, the redox potentials relative to adenine are in very good agreement with experimental results, with MAEs of 0.10 V for CBS-QB3 and 0.07 V for B3LYP. In aqueous solution, B3LYP and CBS-QB3 have MAEs of 0.21 and 0.19 V for E7(X(•),H(+)/XH). Replacing the methyl substituent with ribose changes the calculated E7 potentials by 0.1-0.2 V. The calculated difference between the guanine and adenine oxidation potentials is too large compared to experimental results, but the calculated difference between

  18. Effect of dietary poly unsaturated fatty acids on total brain lipid concentration and anxiety levels of electron beam irradiated mice

    International Nuclear Information System (INIS)

    Suchetha Kumari; Bekal, Mahesh

    2013-01-01

    The whole brain irradiation causes injury to the nervous system at various levels. Omega-3 poly unsaturated fatty acids are very much essential for the growth and development of nervous system. Dietary supplementation of these nutrients will promote the development of injured neuronal cells. Therefore this study was undertaken to establish the role of Omega-3 poly unsaturated fatty acids on total brain lipid concentration, lipid peroxidation and anxiety levels in the irradiated mice. The effect of Electron Beam Radiation (EBR) on total brain lipid concentration, lipid peroxidation and anxiety level were investigated in male Swiss albino mice. The study groups were subjected to a sub-lethal dose of EBR and also the flax seed extract and fish oil were given orally to the irradiated mice. Irradiated groups show significant elevation in anxiety levels when compared to control group, indicating the acute radiation effects on the central nervous system. But the oral supplementation of dietary PUFA source decrees the anxiety level in the irradiated group. The analysis of lipid peroxidation showed a significant level of changes when compared between control and radiation groups. Dietary PUFA supplementation showed a significant level of decrease in the lipid peroxidation in the irradiated groups. The observation of total lipids in brain shows decrease in concentration in the irradiated groups, the differences in the variables follow the similar patterns as of that the MDA levels. This study suggests that the dietary intake of PUFAs may help in prevention and recovery of the oxidative stress caused by radiation. (author)

  19. Chirality Emergence in Thin Solid Films of Amino Acids by Polarized Light from Synchrotron Radiation and Free Electron Laser

    Directory of Open Access Journals (Sweden)

    Mashahiro Adachi

    2009-07-01

    Full Text Available One of the most attractive hypothesis for the origin of homochirality in terrestrial bioorganic compounds is that a kind of “chiral impulse” as an asymmetric excitation source induced asymmetric reactions on the surfaces of such materials such as meteorites or interstellar dusts prior to the existence of terrestrial life (Cosmic Scenario. To experimentally introduce chiral structure into racemic films of amino acids (alanine, phenylalanine, isovaline, etc., we irradiated them with linearly polarized light (LPL from synchrotron radiation and circularly polarized light (CPL from a free electron laser. After the irradiation, we evaluated optical anisotropy by measuring the circular dichroism (CD spectra and verified that new Cotton peaks appeared at almost the same peak position as those of the corresponding non-racemic amino acid films. With LPL irradiation, two-dimensional anisotropic structure expressed as linear dichroism and/or linear birefringence was introduced into the racemic films. With CPL irradiation, the signs of the Cotton peaks exhibit symmetrical structure corresponding to the direction of CPL rotation. This indicates that some kinds of chiral structure were introduced into the racemic film. The CD spectra after CPL irradiation suggest the chiral structure should be derived from not only preferential photolysis but also from photolysis-induced molecular structural change. These results suggest that circularly polarized light sources in space could be associated with the origin of terrestrial homochirality; that is, they would be effective asymmetric exciting sources introducing chiral structures into bio-organic molecules or complex organic compounds.

  20. DFT approach to (benzylthio)acetic acid: Conformational search, molecular (monomer and dimer) structure, vibrational spectroscopy and some electronic properties

    Science.gov (United States)

    Sienkiewicz-Gromiuk, Justyna

    2018-01-01

    The DFT studies were carried out with the B3LYP method utilizing the 6-31G and 6-311++G(d,p) basis sets depending on whether the aim of calculations was to gain the geometry at equilibrium, or to calculate the optimized molecular structure of (benzylthio)acetic acid (Hbta) in the forms of monomer and dimer. The minimum conformational energy search was followed by the potential energy surface (PES) scan of all rotary bonds existing in the acid molecule. The optimized geometrical monomeric and dimeric structures of the title compound were compared with the experimental structural data in the solid state. The detailed vibrational interpretation of experimental infrared and Raman bands was performed on the basis of theoretically simulated ESFF-scaled wavenumbers calculated for the monomer and dimer structures of Hbta. The electronic characteristics of Hbta is also presented in terms of Mulliken atomic charges, frontier molecular orbitals and global reactivity descriptors. Additionally, the MEP and ESP surfaces were computed to predict coordination sites for potential metal complex formation.

  1. Chirality Emergence in Thin Solid Films of Amino Acids by Polarized Light from Synchrotron Radiation and Free Electron Laser

    Science.gov (United States)

    Takahashi, Jun-ichi; Shinojima, Hiroyuki; Seyama, Michiko; Ueno, Yuko; Kaneko, Takeo; Kobayashi, Kensei; Mita, Hajime; Adachi, Mashahiro; Hosaka, Masahito; Katoh, Masahiro

    2009-01-01

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bioorganic compounds is that a kind of “chiral impulse” as an asymmetric excitation source induced asymmetric reactions on the surfaces of such materials such as meteorites or interstellar dusts prior to the existence of terrestrial life (Cosmic Scenario). To experimentally introduce chiral structure into racemic films of amino acids (alanine, phenylalanine, isovaline, etc.), we irradiated them with linearly polarized light (LPL) from synchrotron radiation and circularly polarized light (CPL) from a free electron laser. After the irradiation, we evaluated optical anisotropy by measuring the circular dichroism (CD) spectra and verified that new Cotton peaks appeared at almost the same peak position as those of the corresponding non-racemic amino acid films. With LPL irradiation, two-dimensional anisotropic structure expressed as linear dichroism and/or linear birefringence was introduced into the racemic films. With CPL irradiation, the signs of the Cotton peaks exhibit symmetrical structure corresponding to the direction of CPL rotation. This indicates that some kinds of chiral structure were introduced into the racemic film. The CD spectra after CPL irradiation suggest the chiral structure should be derived from not only preferential photolysis but also from photolysis-induced molecular structural change. These results suggest that circularly polarized light sources in space could be associated with the origin of terrestrial homochirality; that is, they would be effective asymmetric exciting sources introducing chiral structures into bio-organic molecules or complex organic compounds. PMID:19742124

  2. Luminescence and Electronic Spectral Studies of Some Synthesized Lanthanide Complexes Using Benzoic Acid Derivative and o-Phenanthroline.

    Science.gov (United States)

    Wankar, Sneha; Limaye, S N

    2015-07-01

    Lanthanide complexes of p-nitrobenzoic acid(p-NBA) and o-phenanthroline(o-phen) namely [Ln2(Phen)2(p-NBA)3(NO3)2].2H2O where, Ln = Sm(III),Tb(III),Dy(III) and [Eu2(Phen)2(p-NBA)3].4H2O were synthesized and further characterized by Elemental analysis, UV spectroscopy, IR spectroscopy, (1)HNMR spectroscopy. Luminescence measurements were performed on all compounds in ethanolic solution. These complexes have showed narrow emission indicating that the organic ligands are better energy absorber and capable of transferring energy to the Ln (III) ion. Furthermore, we reported electronic spectral studies on [Eu2 (Phen)2 (p-NBA)3].4H2O in order to calculate following parameters, viz: Oscillator strength (f), Judd-Ofelt parameters Ωλ (λ = 2,4,6) and Radiative parameters. [Eu2 (o-Phen)2 (p-NBA)3].4H2O showed the strongest emission at 613 nm corresponds to (5)D0→(7)F2 hypersensitive transition, this emission is very sensitive to the environment. However, the larger value of Ω2 supports the presence of the hypersensitive transition (5)D0→(7)F2 which strictly depends on the nature of ligand. All electronic spectral parameters were calculated systemically.

  3. Scanning electron microscopic study of the hydrolytic degradation of poly(glycolic acid) suture

    International Nuclear Information System (INIS)

    Chu, C.C.; Campbell, N.D.

    1982-01-01

    This article reports the morphological observations on the surface changes of poly-(glycolic acid) sutures which have been exposed to various dosages of gamma irradiation (0, 2.5, 5.0, 10, 20 and 40 Mrad) and duration of immersion (0, 7, 14, 28, 48, 60, and 90 days) in a physiological saline buffer. The most important gross morphological characteristics of PGA suture hydrolytic degradation is the formation of surface cracks on the filaments. The regularity of the surface cracks increased with an increase in the gamma irradiation and the duration of hydrolysis. Surface cracks were not observed in irradiated sutures that had not been subjected to hydrolytic degradation. The arrangement of the surface cracks, their orientation on the filaments, and the direction of crack propagation provide very useful information for depicting the mechanism of hydrolytic degradation in this class of fibrous material. The microfibrillar model of fiber structure has been used as the basis for the proposed degradation mechanism of PGA in vitro. It is believed that hydrolysis occurs initially in the amorphous regions sandwiched between two crystalline zones, as tie-chain segments, free chain ends, and chain folds in these regions degrade into fragments. As degradation proceeds, the size of the fragments reaches the stage at which they can be dissolved into the buffer medium. This dissolution removes the fragments from the amorphous regions, and surface cracks appeared

  4. Electronically Stabilized Copoly(Styrene-Acrylic Acid Submicrocapsules Prepared by Miniemulsion Copolymerization

    Directory of Open Access Journals (Sweden)

    Minkwan Kim

    2017-07-01

    Full Text Available This work reports the preparation and characterization of poly(styrene-acrylic acid (St/AA submicrocapsules by using the miniemulsion copolymerization method. AA was introduced to miniemulsion polymerization of St to increase the zeta potential and the resulting electrostatic stability of St/AA submicrocapsules. Phytoncide oil was adopted as the core model material. Miniemulsion copolymerization of St and AA was conducted at a fixed monomer concentration (0.172 mol with a varying monomer feed ratio [AA]/[St] (0.2, 0.25, 0.33, 0.5, and 1.0. Concentrations of initiator (azobisisobutyronitrile; 1.0 × 10−3, 2.0 × 10−3, 3.0 × 10−3, and 4.0 × 10−3 mol/mol of monomer and surfactant (sodium dodecyl sulfate; 0.6 × 10−3, 1.0 × 10−3, and 1.4 × 10−3 mol were also controlled to optimize the miniemulsion copolymerization of St and AA. Dynamic light scattering and microscopic analyses confirmed the optimum condition of miniemulsion copolymerization of St and AA. Long-term colloidal stability of aqueous St/AA submicrocapsule suspension was evaluated by using TurbiscanTM Lab. In this work, the optimum condition for miniemulsion copolymerization of St and AA was determined ([AA]/[St] = 0.33; [SDS] = 1.0 × 10−3 mol; [AIBN] = 2.0 × 10−3 mol/mol of monomer. St/AA submicrocapsules prepared at the optimum condition (392.6 nm and −55.2 mV of mean particle size and zeta potential, respectively showed almost no variations in backscattering intensity (stable colloids without aggregation.

  5. Side chain effect on electronic structure of spin-coated films of [6,6]-phenyl-C61-butyric acid methyl ester and its bis-adduct

    International Nuclear Information System (INIS)

    Akaike, Kouki; Kanai, Kaname; Ouchi, Yukio; Seki, Kazuhiko

    2013-01-01

    Highlights: ► Electronic structure of spin-coated films of PCBM and bis-PCBM was investigated. ► Ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. ► Electron donation from the side chain to C 60 -backbone raises the HOMO and LUMO. ► Open circuit voltages of PCBM-based solar cells relates to electron affinities. - Abstract: We investigated the electronic structure of spin-coated films of two soluble fullerenes; [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) and its bis-adduct (bis-PCBM) using ultraviolet photoelectron spectroscopy, inverse photoemission spectroscopy and molecular orbital calculations. The ionization energy and electron affinity of spin-coated films of bis-PCBM were determined to be 6.01 eV and 3.4 eV, respectively. Analysis of electron density suggested the stronger electron donation from the two side chains to fullerene-backbone in a bis-PCBM molecule, compared with PCBM. The electron donation raises the energies of the frontier orbitals of bis-PCBM, which mainly consist of π-orbitals of fullerene-backbone. As a result, the ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. Moreover, we also concluded that the larger open circuit voltage observed for bis-PCBM based organic photovoltaics was explained by the higher-lying unoccupied molecular orbital of bis-PCBM

  6. Six-frame picosecond radiation camera based on hydrated electron photoabsorption phenomena. [Laser opacity pattern in acidic aqueous cell formed by pulsed irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Coutts, G.W.; Olk, L.B.; Gates, H.A.; St. Leger-Barter, G.

    1977-01-15

    To obtain picosecond photographs of nanosecond radiation sources, a six-frame ultra-high speed radiation camera based on hydrated electron absorption phenomena has been developed. A time-dependent opacity pattern is formed in an acidic aqueous cell by a pulsed radiation source. Six time-resolved picosecond images of this changing opacity pattern are transferred to photographic film with the use of a mode-locked dye laser and six electronically gated microchannel plate image intensifiers. Because the lifetime of the hydrated electron absorption centers can be reduced to picoseconds, the opacity patterns represent time-space pulse profile images.

  7. Comparison of Acid Resistance of Root Dentin after Treatment with a Mid-Infrared Free Electron Laser at between λ=9.0 and 9.7 µm

    Science.gov (United States)

    Heya, Manabu; Sano, Shu; Kumasaki, Hiroaki; Hashishin, Yuichi; Sunada, Kazuhisa; Yoshikawa, Kazushi; Inoue, Masayoshi; Horiike, Hiroshi

    2008-11-01

    The purpose of this study was to compare the acid resistance of root dentin treated with a free electron laser emitting at between λ=9.0 and 9.7 µm, corresponding to the absorption peaks due to the phosphate ions. In order to obtain the optimum irradiation time for effective surface modification in the acid resistance test, we measured the temporal behaviors of acoustic wave emission and temperature rise. Lased and unlased samples were immersed in 0.1 M lactic acid, and the amount of Ca dissolved in the solution was determined after immersion times of 1-22 h. The acid resistances for λ=9.0 and 9.7 µm increased only until ˜3 h. We conclude that the surface modification of root dentin leads to improved acid resistance, but that this only persists for a few hours. Subsurface modification but not surface modification would be effective in the treatment of root surface caries.

  8. [Influence of exogenous salicylic acid on the level of phytohormones in tissues of Phlox paniculata and Phlox setacea leaves with special reference to resistance against the powdery mildew causative agent Erysiphe cichoracearum D.C. f. phlogis Jacz].

    Science.gov (United States)

    Talieva, M N; Kondrat'eva, V V

    2002-01-01

    We studied the effects of exogenous salicylic acid on the level of endogenous cytokinins and abscisic and salicylic acids in the tissues of leaves of phloxes contrasting in resistance against the powdery mildew causative agent: susceptible Phlox paniculata L. and resistant Ph. setacea L. Studies were carried out under the conditions of biotic stress. The initial level of salicylic and abscisic acids and cytokinins is the highest in the resistant phlox species. After treatment with salicylic species, the total level of cytokinins and endogenous salicylic acid increased in both species. When the treated phlox species were infected by the powdery mildew causative agent, the level of abscisic and salicylic acids increased in the susceptible Ph. paniculata, while that of cytokinins increased in the resistant Ph. setacea. The role of salicylic acid in the induction of plant defense reactions against phytopathogens is discussed.

  9. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

    Directory of Open Access Journals (Sweden)

    Suzan Bsat

    2015-04-01

    Full Text Available Advanced additive manufacturing techniques such as electron beam melting (EBM, can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M and immersion times (6, 24 h of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

  10. Theoretical and experimental determination of scaling factors in electron dosimetry for 3D-printed polylactic acid.

    Science.gov (United States)

    Diamantopoulos, Stefanos; Kantemiris, Ioannis; Patatoukas, Georgios; Dilvoi, Maria; Efstathopoulos, Efstathios; Kouloulias, Vassilis; Platoni, Kalliopi

    2018-02-16

    Plastic phantoms are commonly used in daily routine for dosimetric tasks in radiation therapy. Although water is the reference medium according to the dosimetric protocols, measurements with nonwater phantoms are easier to be performed. To succeed absorbed dose determination, certain scaling factors have to be applied to the acquired measurements. Taking into account the increased availability of three-dimensional (3D) printing, we attempted to obtain scaling factors for polylactic acid (PLA), a commonly used thermoplastic material for 3D printing. Measurements were performed with a custom-made phantom from PLA material, which was designed and constructed using 3D printing technology. Depth and fluence scaling factors were obtained within the range of 6 to 20 MeV. Moreover, Monte Carlo simulations were performed to verify the measured results. Experimental and Monte Carlo (MC) values showed a good agreement, especially in lower energies. Mean value of depth scaling factor (c pl ) over the whole range of energies was 0.946, while mean fluence scaling factor (h pl ) was found to be 1.050. For energies below 10 MeV, the corresponding mean values for c pl and h pl were 0.946 and 1.054, respectively. PLA phantoms could be constructed and used for electron beam nonreference measurements, reproducing even more complex geometries, from simple quality assurance devices to geometrically complicated anthropomorphic phantoms. © 2018 American Association of Physicists in Medicine.

  11. Electron microscopic features of brain edema in rodent cerebral malaria in relation to glial fibrillary acidic protein expression.

    Science.gov (United States)

    Ampawong, Sumate; Chaisri, Urai; Viriyavejakul, Parnpen; Nontprasert, Apichart; Grau, Georges E; Pongponratn, Emsri

    2014-01-01

    The mechanisms leading to cerebral malaria (CM) are not completely understood. Brain edema has been suggested as having an important role in experimental CM. In this study, CBA/CaH mice were infected with Plasmodium berghei ANKA blood-stage and when typical symptoms of CM developed on day 7, brain tissues were processed for electron-microscopic and immunohistochemical studies. The study demonstrated ultrastructural hallmarks of cerebral edema by perivascular edema and astroglial dilatation confirming existing evidence of vasogenic and cytogenic edema. This correlates closely with the clinical features of CM. An adaptive response of astrocytic activity, represented by increasing glial fibrillary acidic protein (GFAP) expression in the perivascular area and increasing numbers of large astrocyte clusters were predominately found in the CM mice. The presence of multivesicular and lamellar bodies indicates the severity of cerebral damage in experimental CM. Congestion of the microvessels with occluded white blood cells (WBCs), parasitized red blood cells (PRBCs) and platelets is also a crucial covariate role for CM pathogenesis.

  12. High catalytic activity of monometallic Ag, Cu nanostructures in the degradation of acid blue 113 dye: an electron relay effect

    Science.gov (United States)

    Udayabhaskar, R.; Mangalaraja, R. V.; Pandiyarajan, T.; Karthikeyan, B.; Mansilla, Héctor D.

    2017-09-01

    This report discusses the observed faster decoloration of an azo dye with an enhanced degradation rate constant achieved using metal nanostructures as a catalyst. Silver and copper nanostructures were synthesized by reducing the corresponding nitrate salts using hydrazine and hexamethylenetetramine (HMTA) in sodium hydroxide (NaOH) solution. The influence of HMTA was clearly evident from the scanning electron microscopy (SEM) images; with increasing concentration it caused agglomeration and the formation of net-like nanostructures. An x-ray diffraction study confirmed the formation of monometallic Ag and Cu nanostructures. The prepared nanostructures exhibited dipole and multipole surface plasmon resonance-related optical absorption bands which were size and shape dependent. The degradation of the azo dye acid blue 113 (AB113) in the presence of sodium borohydride (NaBH4) was taken as model system for studying the catalytic activity of the metal nanostructures. From the optical absorption spectral studies of dye degradation it was observed that the rate constant (k) was of the order of k Cu   >  k Ag   >  k no catalyst. From the dye degradation studies a high catalytic activity was observed for Cu nanostructures with a rate constant of 20.93  ×  10-4 s-1.

  13. Scanning Electron Microscope Observations of Powder Sticking on Punches during a Limited Number (N Acetylsalicylic Acid.

    Science.gov (United States)

    Tsosie, Henrietta; Thomas, James; Strong, John; Zavaliangos, Antonios

    2017-10-01

    To obtain quantitative information and mechanistic insight into the problem of sticking of acetylsalicylic acid tablets on a metallic punch. Low voltage scanning electron microscopy was used to observe punch area coverage and morphology of adhered powder on a flat punch used for a limited number of compactions. Material accumulation in terms of area coverage of the punch per compaction cycle was determined at two pressures over five compactions. The distribution of the adhered material on the punch was non-uniform with more material left on the center of the punch. The sizes of the adhered particles range from 1 to 100 μm, with 50% of the punch surface coverage from particles of an equivalent diameter > 30 μm. Three types of adhered particles were identified after the first compaction: (a) fragments of initial particles with very high aspect ratio, (b) nearly equiaxed fragments with multiple cracks, (c) heavily deformed islands of low profile. Some preliminary ideas that explain these observations are presented and discussed. The ability of SEM to provide quantitative information on sticking from few compactions presents an interesting possibility for a material sparing technique that provides insight on the propensity of sticking.

  14. Effective atomic numbers and electron densities of bacteriorhodopsin and its comprising amino acids in the energy range 1 keV–100 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, Morteza; Lunscher, Nolan [Waterloo Institute for Nanotechnology and Department of Systems Design Engineering, University of Waterloo, 200 University Ave., W., Waterloo, Ontario, Canada N2L 3G1 (Canada); Yeow, John T.W., E-mail: jyeow@uwaterloo.ca [Waterloo Institute for Nanotechnology and Department of Systems Design Engineering, University of Waterloo, 200 University Ave., W., Waterloo, Ontario, Canada N2L 3G1 (Canada)

    2013-04-01

    Recently, there has been an interest in fabrication of X-ray sensors based on bacteriorhodopsin, a proton pump protein in cell membrane of Halobacterium salinarium. Therefore, a better understanding of interaction of X-ray photons with bacteriorhodopsin is required. We use WinXCom program to calculate the mass attenuation coefficient of bacteriorhodopsin and its comprising amino acids for photon energies from 1 keV to 100 GeV. These amino acids include alanine, arginine, asparagine, aspartic acid, glutamine, glutamic acid, glycine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, Asx1, Asx2, Glx1 and Glx2. We then use that data to calculate effective atomic number and electron densities for the same range of energy. We also emphasize on two ranges of energies (10–200 keV and 1–20 MeV) in which X-ray imaging and radiotherapy machines work.

  15. A multiplex GC-MS/MS technique for the sensitive and quantitative single-run analysis of acidic phytohormones and related compounds, and its application to Arabidopsis thaliana.

    Science.gov (United States)

    Müller, Axel; Düchting, Petra; Weiler, Elmar W

    2002-11-01

    A highly sensitive and accurate multiplex gas chromatography-tandem mass spectrometry (GC-MS/MS) technique is reported for indole-3-acetic acid, abscisic acid, jasmonic acid, 12-oxo-phytodienoic acid and salicylic acid. The optimized setup allows the routine processing and analysis of up to 60 plant samples of between 20 and 200 mg of fresh weight per day. The protocol was designed and the equipment used was chosen to facilitate implementation of the method into other laboratories and to provide access to state-of-the-art analytical tools for the acidic phytohormones and related signalling molecules. Whole-plant organ-distribution maps for indole-3-acetic acid, abscisic acid, jasmonic acid, 12-oxo-phytodienoic acid and salicylic acid were generated for Arabidopsis thaliana (L.) Heynh. For leaves of A. thaliana, a spatial resolution of hormone quantitation down to approximately 2 mm(2) was achieved.

  16. Single Stage Tandem Mass Spectrometry Assignment of the C-5 Uronic Acid Stereochemistry in Heparan Sulfate Tetrasaccharides using Electron Detachment Dissociation

    Science.gov (United States)

    Agyekum, Isaac; Zong, Chengli; Boons, Geert-Jan; Amster, I. Jonathan

    2017-09-01

    The analysis of heparan sulfate (HS) glycosaminoglycans presents many challenges, due to the high degree of structural heterogeneity arising from their non-template biosynthesis. Complete structural elucidation of glycosaminoglycans necessitates the unambiguous assignments of sulfo modifications and the C-5 uronic acid stereochemistry. Efforts to develop tandem mass spectrometric-based methods for the structural analysis of glycosaminoglycans have focused on the assignment of sulfo positions. The present work focuses on the assignment of the C-5 stereochemistry of the uronic acid that lies closest to the reducing end. Prior work with electron-based tandem mass spectrometry methods, specifically electron detachment dissociation (EDD), have shown great promise in providing stereo-specific product ions, such as the B3 ´ -CO2, which has been found to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA) in some HS tetrasaccharides. The previously observed diagnostic ions are generally not observed with 2- O-sulfo uronic acids or for more highly sulfated heparan sulfate tetrasaccharides. A recent study using electron detachment dissociation and principal component analysis revealed a series of ions that correlate with GlcA versus IdoA for a set of 2- O-sulfo HS tetrasaccharide standards. The present work comprehensively investigates the efficacy of these ions for assigning the C-5 stereochemistry of the reducing end uronic acid in 33 HS tetrasaccharides. A diagnostic ratio can be computed from the sum of the ions that correlate to GlcA to those that correlate to IdoA. [Figure not available: see fulltext.

  17. Fibrin clot adhesion to root surface treated with tetracycline hydrochloride and ethylenediaminetetraacetic acid: A scanning electron microscopic study

    Directory of Open Access Journals (Sweden)

    Chandran Preeja

    2013-01-01

    Full Text Available Background: Connective tissue attachment following periodontal regenerative surgery is directly related to the attachment of fibrin clot on to the root surface during early wound healing events.The adhesion of fibrin clot to the root surface affected by periodontal disease depends on the biologic acceptance of the root surface which can be accomplished by various root conditioning procedures during periodontal therapy. The present in vitro study has been designed to evaluate and compare the degree of fibrin clot adhesion to root surfaces treated with root conditioning agents tetracycline hydrochloride and ethylenediaminetetraacetic acid (EDTA. Materials and Methods: A total of 30 dentin blocks are divided into three groups and treated with tetracycline hydrochloride, EDTA and phosphate buffered saline and a drop of blood is added to each dentin block. The dentin blocks are then prepared for scanning electron microscopic analysis and examined for the degree of fibrin network frmation and entrapped erythrocytes. Results: The degree of fibrin clot adhesion was highest with tetracycline hydrochloride group, then with control group and least with EDTA treated group. Conclusion: According to the results of the present study, root conditioning with tetracycline hydrochloride produces a biologically acceptable root surface with enhanced fibrin clot adhesion, which is a critical step in early wound healing process. EDTA gel appears less effective in producing a root surface necessary for the adhesion of fibrin clot. The control without any root conditioning procedure showed poor fibrin clot adhesion when compared to tetracycline treated group, but when compared to EDTA treated group the fibrin clot adhesion was slightly better.

  18. Acid-etching technique of non-decalcified bone samples for visualizing osteocyte-lacuno-canalicular network using scanning electron microscope.

    Science.gov (United States)

    Lampi, Tiina; Dekker, Hannah; Ten Bruggenkate, Chris M; Schulten, Engelbert A J M; Mikkonen, Jopi J W; Koistinen, Arto; Kullaa, Arja M

    2018-01-01

    The aim of this study was to define the acid-etching technique for bone samples embedded in polymethyl metacrylate (PMMA) in order to visualize the osteocyte lacuno-canalicular network (LCN) for scanning electron microscopy (SEM). Human jaw bone tissue samples (N = 18) were collected from the study population consisting of patients having received dental implant surgery. After collection, the bone samples were fixed in 70% ethanol and non-decalcified samples embedded routinely into polymethyl metacrylate (PMMA). The PMMA embedded specimens were acid-etched in either 9 or 37% phosphoric acid (PA) and prepared for SEM for further analysis. PMMA embedded bone specimens acid-etched by 9% PA concentration accomplishes the most informative and favorable visualization of the LCN to be observed by SEM. Etching of PMMA embedded specimens is recommendable to start with 30 s or 40 s etching duration in order to find the proper etching duration for the samples examined. Visualizing osteocytes and LCN provides a tool to study bone structure that reflects changes in bone metabolism and diseases related to bone tissue. By proper etching protocol of non-decalcified and using scanning electron microscope it is possible to visualize the morphology of osteocytes and the network supporting vitality of bone tissue.

  19. Adsorption of acetic acid on ice studied by ambient-pressure XPS and partial-electron-yield NEXAFS spectroscopy at 230-240 K.

    Science.gov (United States)

    Křepelová, Adéla; Bartels-Rausch, Thorsten; Brown, Matthew A; Bluhm, Hendrik; Ammann, Markus

    2013-01-17

    Ice plays a key role in the environment, and the ice-air interface influences heterogeneous chemical reactions between snowpack or cirrus clouds and the surrounding air. Soluble gases have been suspected to affect the topmost, disordered layer on ice (often referred to as a quasiliquid layer, QLL). Changes are especially expected in the hydrogen-bonding structure of water in the presence of solutes at the ice surface. Here, we used ambient-pressure X-ray photoelectron spectroscopy (XPS) to detect acetic acid at the ice surface at 230-240 K under atmospheric conditions for the first time. Electron-kinetic-energy-dependent C 1s spectra indicate that acetic acid remains confined to the topmost ice surface layers. Spectral analysis provides information about the protonation state of acetate at the ice surface. Surface-sensitive Auger-electron-yield C-edge near-edge X-ray absorption fine structure (NEXAFS) spectra were recorded to probe the molecular state of the adsorbed species. The O-edge NEXAFS spectra show only minor differences between clean ice and ice with adsorbed acetic acid and thus indicate that acetic acid does not lead to an extended disordered layer on the ice surface between 230 and 240 K.

  20. Lewis Acid-Induced Change from Four- to Two-Electron Reduction of Dioxygen Catalyzed by Copper Complexes Using Scandium Triflate

    Science.gov (United States)

    Kakuda, Saya; Rolle, Clarence; Ohkubo, Kei; Siegler, Maxime A.; Karlin, Kenneth D.; Fukuzumi, Shunichi

    2015-01-01

    Mononuclear copper complexes, [(tmpa)CuII(CH3CN)](ClO4)2 (1, tmpa = tris(2-pyridylmethyl)amine) and [(BzQ)CuII(H2O)2](ClO4)2 (2, BzQ = bis(2-quinolinylmethyl)benzylamine)], act as efficient catalysts for the selective two-electron reduction of O2 by ferrocene derivatives in the presence of scandium triflate (Sc(OTf)3), in acetone, whereas 1 catalyzes the four-electron reduction of O2 by the same reductant in the presence of Brønsted acids such as triflic acid. Following formation of the peroxo-bridged dicopper(II) complex [(tmpa)CuII(O2)CuII(tmpa)]2+, the two-electron reduced product of O2 with Sc3+ is observed to be scandium peroxide ([Sc3+(O22−)]+). In the presence of three equiv of hexamethylphosphoric triamide (HMPA), [Sc3+(O22−)]+ was oxidized by [Fe(bpy)3]3+ (bpy = 2,2′-bipyridine) to the known superoxide species [(HMPA)3Sc3+(O2•−)]2+ as detected by EPR spectroscopy. A kinetic study revealed that the rate-determining step of the catalytic cycle for the two-electron reduction of O2 with 1 is electron transfer from Fc* to 1 to give a cuprous complex which is highly reactive toward O2, whereas the rate-determining step with 2 is changed to the reaction of the cuprous complex with O2 following electron transfer from ferrocene derivatives to 2. The explanation for the change in catalytic O2-reaction stoichiometry from four-electron with Brønsted acids to two-electron reduction in the presence of Sc3+ and also for the change in the rate-determining step is clarified based on a kinetics interrogation of the overall catalytic cycle as well as each step of the catalytic cycle with study of the observed effects of Sc3+ on copper-oxygen intermediates. PMID:25659416

  1. Comparative study of the radio-frequency magnetron sputter deposited CaP films fabricated onto acid-etched or pulsed electron beam-treated titanium

    International Nuclear Information System (INIS)

    Surmeneva, M.A.; Surmenev, R.A.; Tyurin, A.I.; Mukhametkaliyev, T.M.; Teresov, A.D.; Koval, N.N.; Pirozhkova, T.S.; Shuvarin, I.A.; Oehr, C.

    2014-01-01

    This study investigated the effect of the substrate morphology introduced by various substrate preparation techniques, namely acid etching (AE) and pulsed electron beam (PEB) treatments, on the CaP film morphology and mechanical properties. The morphology, nanohardness, and Young's modulus of the CaP coating deposited via radio-frequency (RF) magnetron sputtering were investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), scanning electron microscopy and nanoindentation studies. The Ca/P ratios of the CaP coating deposited via RF magnetron sputtering onto titanium substrates treated using AE and PEB according to XPS were 1.73 ± 0.03 and 1.72 ± 0.04, respectively, which is close to the Ca/P ratio of 1.67 typical for stoichiometric hydroxyapatite (HA). The AFM experiments and nanoindentation studies revealed significant differences in the morphology and mechanical responses of the CaP films deposited onto acid-etched titanium substrates treated with PEB. Deposition of the CaP coating onto the acid-etched surface resulted in a rough surface with the presence of an island-like morphology. The CaP coating onto a smooth titanium substrate treated by PEB exhibited grains with irregular shapes and decreased size. The nanoindentation hardness and the Young's modulus of the HA coating deposited onto titanium treated by the PEB treatment were determined to be 7.0 ± 0.3 and 124 ± 3 GPa, respectively, which are significantly higher than those of the CaP coating on the acid-etched titanium substrates. Moreover, the elastic strain to failure (H/E), the plastic deformation resistance (H 3 /E 2 ), and the percent elastic recovery %R of the HA coating on titanium after surface irradiation with an electron energy density of 15 J·cm −2 were determined to increase by ∼ 23%, ∼ 70% and ∼ 53%, respectively, compared to the CaP coating on acid-etched titanium. - Highlights: • Island-like morphology of calcium phosphate coating on

  2. Kinetics and Mechanism of Electron Transfer Reaction: Oxidation of Sulfanilic Acid by N-Chloro-p-Toluene Sulfonamide in Acid Perchlorate Medium

    International Nuclear Information System (INIS)

    Sailani, Riya; Bhasin, Meneka; Khandelwal, C. L.; Sharma, P. D.

    2014-01-01

    The kinetics and mechanism of oxidation of sulfanilic acid by N-chloro-p-toluene sulfonamide (chloramine-T) have been studied in acid medium. The species of chloramine-T were analysed on the basis of experimental observations and predominantly reactive species was taken into account for proposition of most plausible reaction mechanism. The derived rate law (1) conforms to such a mechanism. All kinetic parameters were evaluated. Activation parameters such as energy and entropy of activation were calculated to be (61.67 ± 0.47) kJ mol -1 and (-62.71 ± 2.48) JK -1 mol -1 respectively employing Eyring equation

  3. Investigating the Secondary Structure of Membrane Peptides Utilizing Multiple 2H-Labeled Hydrophobic Amino Acids via Electron Spin Echo Envelope Modulation (ESEEM) Spectroscopy.

    Science.gov (United States)

    Liu, Lishan; Sahu, Indra D; Bottorf, Lauren; McCarrick, Robert M; Lorigan, Gary A

    2018-04-12

    An electron spin echo envelope modulation (ESEEM) approach was used to probe local secondary structures of membrane proteins and peptides. This ESEEM method detects dipolar couplings between 2 H-labeled nuclei on the side chains of an amino acid (Leu or Val) and a strategically placed nitroxide spin-label in the proximity up to 8 Å. ESEEM spectra patterns for different samples correlate directly to the periodic structural feature of different secondary structures. Since this pattern can be affected by the side chain length and flexibility of the 2 H-labeled amino acid used in the experiment, it is important to examine several different hydrophobic amino acids (d 3 Ala, d 8 Val, d 8 Phe) utilizing this ESEEM approach. In this work, a series of ESEEM data were collected on the AChR M2δ membrane peptide to build a reference for the future application of this approach for various biological systems. The results indicate that, despite the relative intensity and signal-to-noise level, all amino acids share a similar ESEEM modulation pattern for α-helical structures. Thus, all commercially available 2 H-labeled hydrophobic amino acids can be utilized as probes for the further application of this ESEEM approach. Also, the ESEEM signal intensities increase as the side chain length gets longer or less rigid. In addition, longer side chain amino acids had a larger 2 H ESEEM FT peak centered at the 2 H Larmor frequency for the i ± 4 sample when compared to the corresponding i ± 3 sample. For shorter side chain amino acids, the 2 H ESEEM FT peak intensity ratio between i ± 4 and i ± 3 was not well-defined.

  4. An Experimental and Theoretical Investigation of the Electronic Structures and Photoelectrical Properties of Ethyl Red and Carminic Acid for DSSC Application

    Directory of Open Access Journals (Sweden)

    Chaofan Sun

    2016-10-01

    Full Text Available The photoelectrical properties of two dyes—ethyl red and carminic acid—as sensitizers of dye-sensitized solar cells were investigated in experiments herein described. In order to reveal the reason for the difference between the photoelectrical properties of the two dyes, the ground state and excited state properties of the dyes before and after adsorbed on TiO2 were calculated via density functional theory (DFT and time-dependent DFT (TDDFT. The key parameters including the light harvesting efficiency (LHE, the driving force of electron injection ( Δ G inject and dye regeneration ( Δ G regen , the total dipole moment ( μ normal , the conduction band of edge of the semiconductor ( Δ E CB , and the excited state lifetime (τ were investigated, which are closely related to the short-circuit current density ( J sc and open circuit voltage ( V oc . It was found that the experimental carminic acid has a larger J sc and V oc , which are interpreted by a larger amount of dye adsorbed on a TiO2 photoanode and a larger Δ G regen , excited state lifetime (τ, μ normal , and Δ E CB . At the same time, chemical reactivity parameters illustrate that the lower chemical hardness (h and higher electron accepting power (ω+ of carminic acid have an influence on the short-circuit current density. Therefore, carminic acid shows excellent photoelectric conversion efficiency in comparison with ethyl red.

  5. Interaction of hydrated electron with dietary flavonoids and phenolic acids. Rate constants and transient spectra studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Cai, Zhongli; Li, Xifeng; Katsumura, Yosuke

    2000-01-01

    The reaction rate constants and transient spectra of 11 flavonoids and 4 phenolic acids reacting with e aq - at neutral pH were measured. The results suggest that C 4 keto group is the active site for e aq - to attack on flavonoids and phenolic acids, while the o-dihydroxy structure in B-ring, the C 2,3 double bond, the C 3 -OH group and glycosylation have little effects on the e aq - scavenging activities. (author)

  6. Fast Hydrazone Reactants: Electronic and Acid/Base Effects Strongly Influence Rate at Biological pH

    OpenAIRE

    Kool, Eric T.; Park, Do-Hyoung; Crisalli, Pete

    2013-01-01

    Kinetics studies with structurally varied aldehydes and ketones in aqueous buffer at pH 7.4 reveal that carbonyl compounds with neighboring acid/base groups form hydrazones at accelerated rates. Similarly, tests of a hydrazine with a neighboring carboxylic acid group show that it also reacts at an accelerated rate. Rate constants for the fastest carbonyl/hydrazine combinations are 2–20 M−1sec−1, which is faster than recent strain-promoted cycloaddition reactions.

  7. Ionic liquid based on α-amino acid anion and N7,N9-dimethylguaninium cation ([dMG][AA]): theoretical study on the structure and electronic properties.

    Science.gov (United States)

    Shakourian-Fard, Mehdi; Fattahi, Alireza; Bayat, Ahmad

    2012-06-07

    The interactions between five amino acid based anions ([AA](-) (AA = Gly, Phe, His, Try, and Tyr)) and N7,N9-dimethylguaninium cation ([dMG](+)) have been investigated by the hybrid density functional theory method B3LYP together with the basis set 6-311++G(d,p). The calculated interaction energy was found to decrease in magnitude with increasing side-chain length in the amino acid anion. The interaction between the [dMG](+) cation and [AA](-) anion in the most stable configurations of ion pairs is a hydrogen bonding interaction. These hydrogen bonds (H bonds) were analyzed by the quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analysis. Finally, several correlations between electron densities in bond critical points of hydrogen bonds and interaction energy as well as vibrational frequencies in the most stable configurations of ion pairs have been checked.

  8. Effect of electron beam irradiation on thermal and mechanical properties of poly (lactic acid)/poly (ethylene-co-glycidyl methacrylate) blend

    Science.gov (United States)

    Kumar, Ashish; Rao, T. Venkatappa; Chowdhury, S. Ray; Reddy, S. V. S. R.

    2017-06-01

    Physiochemical blend of Poly (lactic acid) (PLA)/Poly (ethylene-co-glycidyl methacrylate) (PEGMA) has been prepared by using twin-screw Micro compounder. The weight ratio of the blends was fixed at 80:20 (PLA: PEGMA). After that, the multipurpose test specimens -ASTM D638 of resulting blend and pristine PLA were prepared by injection moulding with mould temperature 32˚C. Furthermore, some test Specimens -ASTM D256 also prepared for notch impact test. The prepared samples were exposed to electron beam irradiation at different doses. These samples (un-irradiated and irradiated) were tested for mechanical and thermal properties. A detailed study is made by observing the improvement in the mechanical and thermal properties of the prepared blends with and without electron beam irradiation.

  9. Molecular docking, vibrational, structural, electronic and optical studies of {4 - (2, 6) dichlorophenyl amino 2 - methylidene 4 - oxobutanoic acid and 4- (2, 5)} dichlorophenyl amino 2 - methylidene 4 - oxobutanoic acid - A comparative study

    Science.gov (United States)

    Vanasundari, K.; Balachandran, V.; Kavimani, M.; Narayana, B.

    2018-03-01

    Spectroscopic and structural investigations of 4 - [(2, 6 - dichlorophenyl) amino] 2 -methylidene 4 - oxobutanoic acid (6DAMB) and 4-[(2, 5- dichlorophenyl) amino] 2 - methylidene 4 - oxobutanoic acid (5DAMB) are presented by using experimental (FT-IR and FT-Raman) spectra and theoretical (DFT approach) calculations. Seventy-two characteristic vibrational bands of the title compounds were assigned and compared with available experimental data. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization was analyzed using natural bond orbital (NBO) analysis. Several descriptors determined from the energies of frontier molecular orbital (HOMO and LUMO) were applied to describe the reactivity of the title compound. The dipole moment and first hyperpolarizabilities of the studied compounds indicate that the compound is a good candidate of nonlinear optical materials. Theoretical Ultraviolet-Visible spectra of title compounds have been analyzed using the TD-DFT method. The noncovalent interactions like hydrogen bonding and Van der Waals interaction were identified from the molecular geometry and electron localization function. These interactions in molecules have been studied by using reduced density gradient (RDG) and graphed by Multiwfn. Auto-dock studies reveal that butanoic acid derivatives play a vital role in bonding and results draw us to the concluded that both compounds inhibit Placenta growth factor (PIGF-1) and that have good biological activities. This study may also provide further investigation on butanoic acid derivatives for pharmacological importance.

  10. Distinguishing of Ile/Leu amino acid residues in the PP3 protein by (hot) electron capture dissociation in Fourier transform ion cyclotron resonance mass spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Haselmann, Kim F; Sørensen, Esben Skipper

    2003-01-01

    In hot electron capture dissociation (HECD), multiply protonated polypeptides fragment upon capturing approximately 11-eV electrons. The excess of energy upon the primary c, z* cleavage induces secondary fragmentation in z* fragments. The resultant w ions allow one to distinguish between the isom......In hot electron capture dissociation (HECD), multiply protonated polypeptides fragment upon capturing approximately 11-eV electrons. The excess of energy upon the primary c, z* cleavage induces secondary fragmentation in z* fragments. The resultant w ions allow one to distinguish between...... the isomeric Ile and Leu residues. The analytical utility of HECD is evaluated using tryptic peptides from the bovine milk protein PP3 containing totally 135 amino acid residues. Using a formal procedure for Ile/Leu (Xle) residue assignment, the identities of 20 out of 25 Xle residues (80%) were determined....... The identity of an additional two residues could be correctly guessed from the absence of the alternative w ions, and only two residues, for which neither expected nor alternative w ions were observed, remained unassigned. Reinspection of conventional ECD spectra also revealed the presence of Xle w ions...

  11. Interaction of hydrated electron with dietary flavonoids and phenolic acids. Rate constants and transient spectra studied by pulse radiolysis

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Zhongli; Li, Xifeng; Katsumura, Yosuke [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab

    2000-03-01

    The reaction rate constants and transient spectra of 11 flavonoids and 4 phenolic acids reacting with e{sub aq}{sup -} at neutral pH were measured. The results suggest that C{sub 4} keto group is the active site for e{sub aq}{sup -} to attack on flavonoids and phenolic acids, while the o-dihydroxy structure in B-ring, the C{sub 2,3} double bond, the C{sub 3}-OH group and glycosylation have little effects on the e{sub aq}{sup -} scavenging activities. (author)

  12. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

    NARCIS (Netherlands)

    Bsat, S.; Yavari, S.; Munsch, M.; Valstar, E.R.; Zadpoor, A.A.

    2015-01-01

    Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be

  13. Silencing the SpMPK1, SpMPK2, and SpMPK3 Genes in Tomato Reduces Abscisic Acid—Mediated Drought Tolerance

    Directory of Open Access Journals (Sweden)

    Yan Liang

    2013-11-01

    Full Text Available Drought is a major threat to agriculture production worldwide. Mitogen-activated protein kinases (MAPKs play a pivotal role in sensing and converting stress signals into appropriate responses so that plants can adapt and survive. To examine the function of MAPKs in the drought tolerance of tomato plants, we silenced the SpMPK1, SpMPK2, and SpMPK3 genes in wild-type plants using the virus-induced gene silencing (VIGS method. The results indicate that silencing the individual genes or co-silencing SpMPK1, SpMPK2, and SpMPK3 reduced the drought tolerance of tomato plants by varying degrees. Co-silencing SpMPK1 and SpMPK2 impaired abscisic acid (ABA-induced and hydrogen peroxide (H2O2-induced stomatal closure and enhanced ABA-induced H2O2 production. Similar results were observed when silencing SpMPK3 alone, but not when SpMPK1 and SpMPK2 were individually silenced. These data suggest that the functions of SpMPK1 and SpMPK2 are redundant, and they overlap with that of SpMPK3 in drought stress signaling pathways. In addition, we found that SpMPK3 may regulate H2O2 levels by mediating the expression of CAT1. Hence, SpMPK1, SpMPK2, and SpMPK3 may play crucial roles in enhancing tomato plants’ drought tolerance by influencing stomatal activity and H2O2 production via the ABA-H2O2 pathway.

  14. Comparison of electron beam and gamma ray irradiations effects on ruminal crude protein and amino acid degradation kinetics, and in vitro digestibility of cottonseed meal

    International Nuclear Information System (INIS)

    Ghanbari, F.; Ghoorchi, T.; Shawrang, P.; Mansouri, H.; Torbati-Nejad, N.M.

    2012-01-01

    This study was conducted to compare effects of electron beam (EB) and gamma ray (GR) treatments at doses of 25, 50 and 75 kGy on ruminal degradation kinetics of crude protein (CP), amino acid (AA), and in vitro digestibility of cottonseed meal (CSM). Ionizing radiations of EB and GR had significant effects (P 0.05). Irradiation processing caused decrement in AA degradation after 16 h of ruminal incubation (P<0.05). EB irradiation was more effective than GR irradiation in lessening the ruminal degradability of AA (P<0.05). EB and GR treatments at a dose of 75 kGy increased in vitro digestibility of CSM numerically. This study showed that EB could cause CP and AA bypass rumen as well as GR. Therefore, ionizing irradiation processing can be used as an efficient method in improving nutritional value of CSM. - Highlights: ► Irradiation was effective on reducing ruminal degradability of cottonseed meal. ► Ionizing radiations, especially electron beam, lessened ruminal degradability of amino acid substantially. ► Irradiation processing could be used as a safe and efficient method in improving nutritional value of cottonseed meal.

  15. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production: Progress report, February 1, 1987-February 1, 1988

    International Nuclear Information System (INIS)

    Zeikus, J.G.; Shen, Gwo-Jenn.

    1988-01-01

    These studies concern the fundamental biochemical mechanisms that control carbon and electron flow in anaerobic bacteria that conserve energy when coupling hydrogen consumption to the production of acetic, propionic, or butyric acids. Two acidogens, Propionispira arboris and Butyribacterium methylotrophicum were chosen as model systems to understand the function of oxidoreductases and electron carriers in the regulation of hydrogen metabolism and single carbon metabolism. In P. arboris, H 2 consumption was linked to the inhibition of CO 2 production and an increase in the propionate/acetate rate; whereas, H 2 consumption was linked to a stimulation of CO 2 consumption and an increase in the butyrate/acetate ratio in B. methylotrophicum. We report studies on the enzymes involved in the regulation of singe carbon metabolism, the enzyme activities and pathways responsible for conversion of multicarbon components to acetate and propionate or butyrate, and how low pH inhibits H 2 and acetic acid production in Sarcina ventriculi as a consequence of hydrogenase regulation. 9 refs

  16. Competitive fragmentation pathways of acetic acid dimer explored by synchrotron VUV photoionization mass spectrometry and electronic structure calculations

    Energy Technology Data Exchange (ETDEWEB)

    Guan Jiwen; Hu Yongjun; Zou Hao [MOE Key laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Cao Lanlan; Liu Fuyi; Shan Xiaobin; Sheng Liusi [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029 (China)

    2012-09-28

    In present study, photoionization and dissociation of acetic acid dimers have been studied with the synchrotron vacuum ultraviolet photoionization mass spectrometry and theoretical calculations. Besides the intense signal corresponding to protonated cluster ions (CH{sub 3}COOH){sub n}{center_dot}H{sup +}, the feature related to the fragment ions (CH{sub 3}COOH)H{sup +}{center_dot}COO (105 amu) via {beta}-carbon-carbon bond cleavage is observed. By scanning photoionization efficiency spectra, appearance energies of the fragments (CH{sub 3}COOH){center_dot}H{sup +} and (CH{sub 3}COOH)H{sup +}{center_dot}COO are obtained. With the aid of theoretical calculations, seven fragmentation channels of acetic acid dimer cations were discussed, where five cation isomers of acetic acid dimer are involved. While four of them are found to generate the protonated species, only one of them can dissociate into a C-C bond cleavage product (CH{sub 3}COOH)H{sup +}{center_dot}COO. After surmounting the methyl hydrogen-transfer barrier 10.84 {+-} 0.05 eV, the opening of dissociative channel to produce ions (CH{sub 3}COOH){sup +} becomes the most competitive path. When photon energy increases to 12.4 eV, we also found dimer cations can be fragmented and generate new cations (CH{sub 3}COOH){center_dot}CH{sub 3}CO{sup +}. Kinetics, thermodynamics, and entropy factors for these competitive dissociation pathways are discussed. The present report provides a clear picture of the photoionization and dissociation processes of the acetic acid dimer in the range of the photon energy 9-15 eV.

  17. Hydrogen Bonding, (1)H NMR, and Molecular Electron Density Topographical Characteristics of Ionic Liquids Based on Amino Acid Cations and Their Ester Derivatives.

    Science.gov (United States)

    Rao, Soniya S; Bejoy, Namitha Brijit; Gejji, Shridhar P

    2015-08-13

    Amino acid ionic liquids (AAILs) have attracted significant attention in the recent literature owing to their ubiquitous applications in diversifying areas of modern chemistry, materials science, and biosciences. The present work focuses on unraveling the molecular interactions underlying AAILs. Electronic structures of ion pairs consisting of amino acid cations ([AA(+)], AA = Gly, Ala, Val, Leu, Ile, Pro, Ser, Thr) and their ester substituted derivatives [AAE(+)] interacting with nitrate anion [NO3(-)] have been obtained from the dispersion corrected M06-2x density functional theory. The formation of ion pair is accompanied by the transfer of proton from quaternary nitrogen to anion facilitated via hydrogen bonding. The [Ile], [Pro], [Ser], and [Thr] and their esters reveal relatively strong inter- as well as intramolecular hydrogen-bonding interactions. Consequently, the hierarchy in binding energies of [AA][NO3] ion pairs and their ester analogues turns out to be [Gly] > [Ala] > [Ser] ∼ [Val] ∼ [Ile] > [Leu] ∼ [Thr] > [Pro]. The work underlines how the interplay of intra- as well as intermolecular hydrogen-bonding interactions in [AA]- and [AAE]-based ILs manifest in their infrared and (1)H NMR spectra. Substitution of -OCH3 functional group in [AA][NO3] ILs lowers the melting point attributed to weaker hydrogen-bonding interactions, making them suitable for room temperature applications. As opposed to gas phase structures, the presence of solvent (DMSO) does not bring about any proton transfer in the ion pairs or their ester analogues. Calculated (1)H NMR chemical shifts of the solvated structures agree well with those from experiment. Correlations of decomposition temperatures in [AA]- and [AAE]-based ILs with binding energies and electron densities at the bond critical point(s) in molecular electron density topography, have been established.

  18. Use of 3-(4-hydroxyphenyl)propionic acid as electron donating compound in a potentiometric aflatoxin M{sub 1}-immunosensor

    Energy Technology Data Exchange (ETDEWEB)

    Rameil, Steffen, E-mail: s.rameil@r-biopharm.de [R-Biopharm AG, An der neuen Bergstrasse 17, 64297 Darmstadt (Germany); Schubert, Peter, E-mail: p.schubert@r-biopharm.de [R-Biopharm AG, An der neuen Bergstrasse 17, 64297 Darmstadt (Germany); Grundmann, Peter, E-mail: peter.grundmann@jennewein-biotech.de [R-Biopharm AG, An der neuen Bergstrasse 17, 64297 Darmstadt (Germany); Dietrich, Richard, E-mail: R.Dietrich@mh.vetmed.uni-muenchen.de [Department of Veterinary Sciences, University of Munich, Schoenleutner Str 8, 85764 Oberschleissheim (Germany); Maertlbauer, Erwin, E-mail: E.Maertlbauer@mh.vetmed.uni-muenchen.de [Department of Veterinary Sciences, University of Munich, Schoenleutner Str 8, 85764 Oberschleissheim (Germany)

    2010-02-19

    We developed a potentiometric aflatoxin M{sub 1}-immunosensor which utilizes 3-(4-hydroxyphenyl)propionic acid (p-HPPA) as electron donating compound for horseradish peroxidase (HRP; EC 1.11.1.7). The assay system consists of a polypyrrole-surface-working electrode coated with a polyclonal anti-M{sub 1} antibody (pAb-AFM{sub 1}), a Ag/AgCl reference electrode and a HRP-aflatoxin B{sub 1} conjugate (HRP-AFB{sub 1} conjugate). To optimize the potentiometric measuring system p-HPPA as well as related compounds serving as electron donating compounds were compared. Also the influence of different buffer systems, varying pH and substrate concentrations on signal intensity was investigated. Our results suggest that reaction conditions that favor the formation of Pummerer's type ketones lead to an increase in signal intensity rather than formation of fluorescent dye. Comparison with commercial ready-to-use HRP electron donating compounds such as 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), o-phenylenediamine (OPD) or 3,3',5,5'-tetramethylbenzidine (TMB) showed that only 34%, 77% and 49% of the signal intensity of p-HPPA were reached, respectively. The optimized assay had a detection limit of 40 pg mL{sup -1} and allowed detection of 500 pg mL{sup -1} (FDA action limit) aflatoxin M{sub 1} (AFM{sub 1}) in pasteurized milk and UHT-milk containing 0.3-3.8% fat within 10 min without any sample treatment. The working range was between 250 and 2000 pg mL{sup -1} AFM{sub 1}.

  19. A facile, sensitive, and highly specific trinitrophenol assay based on target-induced synergetic effects of acid induction and electron transfer towards DNA-templated copper nanoclusters.

    Science.gov (United States)

    Li, Haiyin; Chang, Jiafu; Hou, Ting; Ge, Lei; Li, Feng

    2016-11-01

    Reliable, selective and sensitive approaches for trinitrophenol (TNP) detection are highly desirable with respect to national security and environmental protection. Herein, a simple and novel fluorescent strategy for highly sensitive and specific TNP assay has been successfully developed, which is based on the quenching of the fluorescent poly(thymine)-templated copper nanoclusters (DNA-CuNCs), through the synergetic effects of acid induction and electron transfer. Upon the addition of TNP, donor-acceptor complexes between the electron-deficient nitro-groups in TNP and the electron-donating DNA templates are formed, resulting in the close proximity between TNP and CuNCs. Moreover, the acidity of TNP contributes to the pH decrease of the system. These factors combine to dramatically quench the fluorescence of DNA-CuNCs, providing a "signal-off" strategy for TNP sensing. The as-proposed strategy demonstrates high sensitivity for TNP assay, and a detection limit of 0.03μM is obtained, which is lower than those reported by using organic fluorescent materials. More significantly, this approach shows outstanding selectivity over a number of TNP analogues, such as 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT), 2,4-dinitrophenol (DNP), 3-nitrophenol (NP), nitrobenzene (NB), phenol (BP), and toluene (BT). Compared with previous studies, this method does not need complex DNA sequence design, fluorescent dye labeling, or sophisticated organic reactions, rendering the strategy with additional advantages of simplicity and cost-effectiveness. In addition, the as-proposed strategy has been adopted for the detection of TNP in natural water samples, indicating its great potential to be applied in the fields of public safety and environmental monitoring. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Light and electron microscopic study of the toxic effect of prolonged lead exposure on the seminiferous tubules of albino rats and the possible protective effect of ascorbic acid.

    Science.gov (United States)

    El Shafai, Adel; Zohdy, Nahed; El Mulla, Khaled; Hassan, Manal; Morad, Noha

    2011-04-01

    Lead has been long recognized as an occupational toxicant. Now, lead is considered to be one of the major environmental pollutants which have serious potential threat to human health. Reports of declining male fertility have renewed interest in the role of environmental and occupational exposures in the etiology of human infertility. The aim of the present work was to investigate the toxic effect of prolonged exposure to lead on albino rat's seminiferous tubules and the possible protective effect of ascorbic acid (vitamin C) on lead toxicity. The study was carried out on 40 adult male albino rats divided into three groups: a control group which comprised three subgroups; negative control which received no treatment and two positive controls receiving an oral daily dose of distilled water or ascorbic acid, respectively. Lead acetate--intoxicated group received lead acetate orally in a dose of 25 mg/kg b.w dissolved in distilled water for 3 months. While the protected group received ascorbic acid orally in a dose of 100 mg/kg b.w daily for 3 months, simultaneously with lead acetate in a similar dose to that of the intoxicated group. By the end of the experimental period, blood samples were collected for estimation of blood lead level. Fresh specimens were taken from the testis and processed for light and electron microscopic examination. Biochemical analysis demonstrated significant increase in the blood lead level in lead intoxicated group compared to the control group, while ascorbic acid--protected group revealed significant decrease in the blood lead level. Light microscopic examination of lead treated group revealed loss of normal architecture of the testicular tissue in the form of thin walled seminiferous tubules with wide lumen and vacuolations in the spermatogenic epithelium mostly separating primary spermatocytes from spermatogonia and surrounding nuclei of Sertoli cells. Apoptotic bodies were found among the basal part of the spermatogenic epithelium

  1. Gas chromatography-electron ionization-mass spectrometry quantitation of valproic acid and gabapentin, using dried plasma spots, for therapeutic drug monitoring in in-home medical care.

    Science.gov (United States)

    Ikeda, Kayo; Ikawa, Kazuro; Yokoshige, Satoko; Yoshikawa, Satoshi; Morikawa, Norifumi

    2014-12-01

    A simple and sensitive gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) method using dried plasma spot testing cards was developed for determination of valproic acid and gabapentin concentrations in human plasma from patients receiving in-home medical care. We have proposed that a simple, easy and dry sampling method is suitable for in-home medical patients for therapeutic drug monitoring. Therefore, in the present study, we used recently developed commercially available easy handling cards: Whatman FTA DMPK-A and Bond Elut DMS. In-home medical care patients can collect plasma using these simple kits. The spots of plasma on the cards were extracted into methanol and then evaporated to dryness. The residues were trimethylsilylated using N-methyl-N-trimethylsilyltrifluoroacetamide. For GC-EI-MS analysis, the calibration curves on both cards were linear from 10 to 200 µg/mL for valproic acid, and from 0.5 to 10 µg/mL for gabapentin. Intra- and interday precisions in plasma were both ≤13.0% (coefficient of variation), and the accuracy was between 87.9 and 112% for both cards within the calibration curves. The limits of quantification were 10 µg/mL for valproic acid and 0.5 µg/mL for gabapentin on both cards. We believe that the present method will be useful for in-home medical care. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Phosphomolybdic acid and ferric iron as efficient electron mediators for coupling biomass pretreatment to produce bioethanol and electricity generation from wheat straw.

    Science.gov (United States)

    Ding, Yi; Du, Bo; Zhao, Xuebing; Zhu, J Y; Liu, Dehua

    2017-03-01

    Phosphomolybdic acid (PMo 12 ) was used as an electron mediator and proton carrier to mediate biomass pretreatment for ethanol production and electricity generation from wheat straw. In the pretreatment, lignin was oxidized anaerobically by PMo 12 with solubilization of a fraction of hemicelluloses, and the PMo 12 was simultaneously reduced. In an external liquid flow cell, the reduced PMo 12 was re-oxidized with generation of electricity. The effects of several factors on pretreatment were investigated for optimizing the conditions. Enzymatic conversion of cellulose and xylan were about 80% and 45%, respectively, after pretreatment of wheat straw with 0.25M PMo 12 , at 95°C for 45min. FeCl 3 was found to be an effective liquid mediator to transfer electrons to air, the terminal electron acceptor. By investigating the effects of various operation parameters and cell structural factors, the highest output power density of about 11mW/cm 2 was obtained for discharging of the reduced PMo 12 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Bottlenecks in bog pine multiplication by somatic embryogenesis and their visualization with the environmental scanning electron microscope.

    Science.gov (United States)

    Vlašínová, Helena; Neděla, Vilem; Đorđević, Biljana; Havel, Ladislav

    2017-07-01

    Somatic embryogenesis (SE) is an important biotechnological technique used for the propagation of many pine species in vitro. However, in bog pine, one of the most endangered tree species in the Czech Republic, limitations were observed, which negatively influenced the development and further germination of somatic embryos. Although initiation frequency was very low-0.95 %, all obtained cell lines were subjected to maturation. The best responding cell line (BC1) was used and subjected to six different variants of the maturation media. The media on which the highest number of early-precotyledonary/cotyledonary somatic embryos was formed was supplemented with 121 μM abscisic acid (ABA) and with 6 % maltose. In the end of maturation experiments, different abnormalities in formation of somatic embryos were observed. For visualization and identification of abnormalities in meristem development during proliferation and maturation processes, the environmental scanning electron microscope was used. In comparison to the classical light microscope, the non-commercial environmental scanning electron microscope AQUASEM II has been found as a very useful tool for the quick recognition of apical meristem disruption and abnormal development. To our knowledge, this is the first report discussing somatic embryogenesis in bog pine. Based on this observation, the cultivation procedure could be enhanced and the method for SE of bog pine optimized.

  4. Poster - 38: On the physical and dosimetric properties of 3D printed electron bolus fabricated using polylactic acid

    International Nuclear Information System (INIS)

    Sasaki, David; Jensen, Martin; Rickey, Daniel W; Dubey, Arbind; Harris, Chad; McCurdy, Boyd

    2016-01-01

    Purpose: 3D printing technology could simplify and improve electron bolus fabrication. The purpose of this study was to characterize the density, dimensional accuracy, uniformity, and attenuation of PLA boluses fabricated with a low-cost 3D printer. Methods: Several solid square slabs were printed with specific requested dimensions and 100% infill using different fill patterns. These pieces were imaged using an x-ray flat panel imager in order to check for uniformity of the prints. Percentage depth doses (PDDs) were measured downstream of the slabs in solid water using a parallel plate chamber and compared to measurements in water in order to characterize attenuation. The dimensions of the PLA slabs were measured using digital calipers. The slabs were also weighed to find their density. Results: The fill pattern used to create boluses can affect the attenuation of the bolus. Fill patterns should be chosen carefully and quality assurance should be done for each printed piece. PLA causes the electron PDD to shift towards shallower depths, compared to water, by 1.7 mm for each centimeter of PLA. Agreement with design dimensions was within 1 mm in the plane of the printer bed, and within 1/3 of a millimeter (roughly the thickness of a single layer), perpendicular to the printer bed. Average density was in the range 1.20 – 1.22. Conclusions: 3D printing shows great promise for use in fabricating electron bolus. This work indicates that printed PLA can be a suitable material provided the increased attenuation is properly accounted for.

  5. Evidence of phytohormones and phenolic acids variability in garden-waste-derived vermicompost leachate, a well-known plant growth stimulant

    Czech Academy of Sciences Publication Activity Database

    Aremu, A.O.; Stirk, W.A.; Kulkarni, M. G.; Tarkowská, Danuše; Turečková, Veronika; Grúz, Jiří; Šubrtová, Michaela; Pěnčík, Aleš; Novák, Ondřej; Doležal, Karel; Strnad, Miroslav; van Staden, J.

    2015-01-01

    Roč. 75, č. 2 (2015), s. 483-492 ISSN 0167-6903 R&D Projects: GA MŠk LK21306; GA ČR GA14-34792S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Abscisic acid * Biostimulant * Brassinosteroids Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.333, year: 2015

  6. An electron conductive polymer, poly-aniline, in gas separation: optimisation of transport properties by alternated acid-base treatment

    International Nuclear Information System (INIS)

    Rebattet, Laurence

    1994-01-01

    The objective of this research thesis is to study the variation of gas permeation properties of poly-aniline during a doping/de-doping/re-doping cycle, and to study the evolution of the separation power of this polymer. Scanning electronic microscopy is used to study the microstructure and more particularly how the doping agent is distributed within the polymer. Permeabilities, diffusion coefficients, sorption solubilities and interaction energies are measured by using coupled permeation and micro-gravimetry-calorimetry methods. A range of gases (H 2 , O 2 , CO 2 , N 2 , CH 4 ) is analysed [fr

  7. Highly Sprouting-Tolerant Wheat Grain Exhibits Extreme Dormancy and Cold Imbibition-Resistant Accumulation of Abscisic Acid.

    Science.gov (United States)

    Kashiwakura, Yu-ichi; Kobayashi, Daisuke; Jikumaru, Yusuke; Takebayashi, Yumiko; Nambara, Eiji; Seo, Mitsunori; Kamiya, Yuji; Kushiro, Tetsuo; Kawakami, Naoto

    2016-04-01

    Pre-harvest sprouting (PHS) of wheat (Triticum aestivum L.) grains induces hydrolyzing enzymes such as α-amylase, which considerably decreases wheat product quality. PHS occurs when cool and wet weather conditions before harvest break dormancy and induce grain germination. In this study, we used PHS-tolerant varieties, Gifu-komugi (Gifu) and OS38, to characterize the mechanisms of both dormancy breakage and dormancy maintenance at low temperatures. Physiologically mature Gifu grains exhibited dormancy after imbibition at 20°C, but germinated at 15°C. In contrast, OS38 grains remained dormant even at temperatures as low as 5°C. Embryo half-grains cut out from the dormant Gifu grains germinated by imbibition at 20°C, similar to conventional varieties worldwide. However, OS38 embryo half-grains were still dormant. Hormonome and pharmacological analyses suggested that ABA and gibberellin metabolism are important for temperature-dependent dormancy maintenance and breakage. Imbibition at 15°C decreased ABA levels but increased gibberellin levels in embryos of freshly harvested Gifu grains. Additionally, low temperatures induced expression of the ABA catabolism genes,TaABA8' OH1 and TaABA8' OH2, and the gibberellin biosynthesis gene,TaGA3ox2, in the embryos. However, in embryos of freshly harvested OS38 grains, ABA levels were increased while gibberellin levels were suppressed at 15°C. In these dormant embryos, low temperatures induced the TaNCED ABA biosynthesis genes, but suppressed TaABA8' OH2 and TaGA3ox2.These results show that the regulatory mechanism influencing the expression of ABA and gibberellin metabolism genes may be critical for dormancy maintenance and breakage at low temperatures. Our findings should help improve PHS-resistant wheat breeding programs. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. Ethylene Interacts with Abscisic Acid to Regulate Endosperm Rupture during Germination: A Comparative Approach Using Lepidium sativum and Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Linkies, A.; Müller, L.; Morris, K.; Turečková, Veronika; Wenk, M.; Cadman, C. S. C.; Corbineau, F.; Strnad, Miroslav; Lynn, J. R .; Finch-Savage, W. E.; Leubner-Metzger, G.

    2009-01-01

    Roč. 21, č. 12 (2009), s. 3803-3822 ISSN 1040-4651 Instituti