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Lange T, Atiq N, Pimenta Lange MJ. GAS2 encodes a 2-oxoglutarate dependent dioxygenase involved in ABA catabolism. Nat Commun 2023; 14:7602. [PMID: 37990018 PMCID: PMC10663614 DOI: 10.1038/s41467-023-43187-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 10/11/2023] [Indexed: 11/23/2023] Open
Affiliation(s)
- Theo Lange
- Technische Universität Braunschweig, Braunschweig, Germany.
| | - Nadiem Atiq
- Technische Universität Braunschweig, Braunschweig, Germany
| | - Maria João Pimenta Lange
- Technische Universität Braunschweig, Braunschweig, Germany.
- Julius Kühn Institute (JKI), Institute for Plant Protection in Horticulture and Urban Green, Braunschweig, Germany.
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2
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Nguyen CH, Yan D, Nambara E. Persistence of Abscisic Acid Analogs in Plants: Chemical Control of Plant Growth and Physiology. Genes (Basel) 2023; 14:genes14051078. [PMID: 37239437 DOI: 10.3390/genes14051078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 03/23/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
Abscisic acid (ABA) is a plant hormone that regulates numerous plant processes, including plant growth, development, and stress physiology. ABA plays an important role in enhancing plant stress tolerance. This involves the ABA-mediated control of gene expression to increase antioxidant activities for scavenging reactive oxygen species (ROS). ABA is a fragile molecule that is rapidly isomerized by ultraviolet (UV) light and catabolized in plants. This makes it challenging to apply as a plant growth substance. ABA analogs are synthetic derivatives of ABA that alter ABA's functions to modulate plant growth and stress physiology. Modifying functional group(s) in ABA analogs alters the potency, selectivity to receptors, and mode of action (i.e., either agonists or antagonists). Despite current advances in developing ABA analogs with high affinity to ABA receptors, it remains under investigation for its persistence in plants. The persistence of ABA analogs depends on their tolerance to catabolic and xenobiotic enzymes and light. Accumulated studies have demonstrated that the persistence of ABA analogs impacts the potency of its effect in plants. Thus, evaluating the persistence of these chemicals is a possible scheme for a better prediction of their functionality and potency in plants. Moreover, optimizing chemical administration protocols and biochemical characterization is also critical in validating the function of chemicals. Lastly, the development of chemical and genetic controls is required to acquire the stress tolerance of plants for multiple different uses.
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Affiliation(s)
- Christine H Nguyen
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON M5S 3B2, Canada
| | - Dawei Yan
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON M5S 3B2, Canada
| | - Eiji Nambara
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON M5S 3B2, Canada
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3
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Hewage KAH, Yang J, Wang D, Hao G, Yang G, Zhu J. Chemical Manipulation of Abscisic Acid Signaling: A New Approach to Abiotic and Biotic Stress Management in Agriculture. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001265. [PMID: 32999840 PMCID: PMC7509701 DOI: 10.1002/advs.202001265] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/11/2020] [Indexed: 05/02/2023]
Abstract
The phytohormone abscisic acid (ABA) is the best-known stress signaling molecule in plants. ABA protects sessile land plants from biotic and abiotic stresses. The conserved pyrabactin resistance/pyrabactin resistance-like/regulatory component of ABA receptors (PYR/PYL/RCAR) perceives ABA and triggers a cascade of signaling events. A thorough knowledge of the sequential steps of ABA signaling will be necessary for the development of chemicals that control plant stress responses. The core components of the ABA signaling pathway have been identified with adequate characterization. The information available concerning ABA biosynthesis, transport, perception, and metabolism has enabled detailed functional studies on how the protective ability of ABA in plants might be modified to increase plant resistance to stress. Some of the significant contributions to chemical manipulation include ABA biosynthesis inhibitors, and ABA receptor agonists and antagonists. Chemical manipulation of key control points in ABA signaling is important for abiotic and biotic stress management in agriculture. However, a comprehensive review of the current knowledge of chemical manipulation of ABA signaling is lacking. Here, a thorough analysis of recent reports on small-molecule modulation of ABA signaling is provided. The challenges and prospects in the chemical manipulation of ABA signaling for the development of ABA-based agrochemicals are also discussed.
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Affiliation(s)
- Kamalani Achala H. Hewage
- Key Laboratory of Pesticide & Chemical BiologyMinistry of EducationCollege of ChemistryCentral China Normal UniversityWuhan430079P. R. China
- International Joint Research Center for Intelligent Biosensor Technology and HealthCentral China Normal UniversityWuhan430079P. R. China
| | - Jing‐Fang Yang
- Key Laboratory of Pesticide & Chemical BiologyMinistry of EducationCollege of ChemistryCentral China Normal UniversityWuhan430079P. R. China
- International Joint Research Center for Intelligent Biosensor Technology and HealthCentral China Normal UniversityWuhan430079P. R. China
| | - Di Wang
- Key Laboratory of Pesticide & Chemical BiologyMinistry of EducationCollege of ChemistryCentral China Normal UniversityWuhan430079P. R. China
- International Joint Research Center for Intelligent Biosensor Technology and HealthCentral China Normal UniversityWuhan430079P. R. China
| | - Ge‐Fei Hao
- Key Laboratory of Pesticide & Chemical BiologyMinistry of EducationCollege of ChemistryCentral China Normal UniversityWuhan430079P. R. China
- International Joint Research Center for Intelligent Biosensor Technology and HealthCentral China Normal UniversityWuhan430079P. R. China
| | - Guang‐Fu Yang
- Key Laboratory of Pesticide & Chemical BiologyMinistry of EducationCollege of ChemistryCentral China Normal UniversityWuhan430079P. R. China
- International Joint Research Center for Intelligent Biosensor Technology and HealthCentral China Normal UniversityWuhan430079P. R. China
- Collaborative Innovation Center of Chemical Science and EngineeringTianjin300072P. R. China
| | - Jian‐Kang Zhu
- Shanghai Center for Plant Stress Biologyand CAS Center of Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghai20032P. R. China
- Department of Horticulture and Landscape ArchitecturePurdue UniversityWest LafayetteIN47907USA
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4
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Abstract
A short, enantioselective synthesis of a newly identified ABA receptor agonist (−)-phaseic acid is described.
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Affiliation(s)
- Wentong Tu
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- China
| | - Chengqing Ning
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- China
- SUSTech Academy for Advanced Interdisciplinary Studies
| | - Jing Xu
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- China
- SUSTech Academy for Advanced Interdisciplinary Studies
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5
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Hsiao PY, Lee SJ, Chen IS, Hsu HY, Chang HS. Cytotoxic cardenolides and sesquiterpenoids from the fruits of Reevesia formosana. PHYTOCHEMISTRY 2016; 130:282-290. [PMID: 27386738 DOI: 10.1016/j.phytochem.2016.06.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/09/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
Bioassay-guided fractionation of the fruits of Reevesia formosana led to isolation of three cardenolides (reevesioside J, reevesioside K, and epi-reevesioside K), three sesquiterpenoids (reevesiterpenol C, reevesiterpenol D, and reevesiterpenol E), and two glycosides (reevesianin A and reevesianin B), along with 46 known compounds. Their structures were determined using spectroscopic techniques. In addition to the reported cytotoxic cardenolides, reevesioside J and strophanthidin exhibited moderate cytotoxicity against the cell lines MCF-7, NCI-H460, and HepG2, with IC50 values of 0.39 ± 0.06 μM and 1.06 ± 0.12 μM for MCF-7, 0.12 ± 0.01 μM and 0.29 ± 0.01 μM for NCI-H460, and 1.09 ± 0.02 μM and 1.72 ± 0.02 μM for HepG2, respectively. Reevesiterpenol E also exhibited the best selective cytotoxicity to the NCI-H460 cell line, with an IC50 value of 3.15 ± 0.22 μM.
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Affiliation(s)
- Pei-Yu Hsiao
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC
| | - Shiow-Ju Lee
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli, 350, Taiwan, ROC
| | - Ih-Sheng Chen
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC; School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC; Research Center for Natural Products and Drug Development, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC
| | - Hsing-Yu Hsu
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli, 350, Taiwan, ROC
| | - Hsun-Shuo Chang
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC; School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC; Research Center for Natural Products and Drug Development, Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC; Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 807, Taiwan, ROC.
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6
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Yamashita Y, Ota M, Inoue Y, Hasebe Y, Okamoto M, Inukai T, Masuta C, Sakihama Y, Hashidoko Y, Kojima M, Sakakibara H, Inage Y, Takahashi K, Yoshihara T, Matsuura H. Chemical Promotion of Endogenous Amounts of ABA in Arabidopsis thaliana by a Natural Product, Theobroxide. PLANT & CELL PHYSIOLOGY 2016; 57:986-99. [PMID: 26917631 DOI: 10.1093/pcp/pcw037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 02/14/2016] [Indexed: 05/21/2023]
Abstract
Plant hormones are a group of structurally diverse small compounds that orchestrate the cellular processes governing proper plant growth and environmental adaptation. To understand the details of hormonal activity, we must study not only their inherent activities but also the cross-talk among plant hormones. In addition to their use in agriculture, plant chemical activators, such as probenazole and uniconazole, have made great contributions to understand hormonal cross-talk. However, the use of plant chemical activators is limited due to the lack of activators for certain hormones. For example, to the best of our knowledge, there are only a few chemical activators previously known to stimulate the accumulation of ABA in plants, such as absinazoles and proanthocyanidins. In many cases, antagonistic effects have been examined in experiments using exogenously applied ABA, although these studies did not account for biologically relevant concentrations. In this report, it was found that a natural product, theobroxide, had potential as a plant chemical activator for stimulating the accumulation of ABA. Using theobroxide, the antagonistic effect of ABA against GAs was proved without exogenously applying ABA or using mutant plants. Our results suggest that ABA levels could be chemically controlled to elicit ABA-dependent biological phenomena.
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Affiliation(s)
- Yudai Yamashita
- Laboratory of Natural Product Chemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Maremichi Ota
- Laboratory of Natural Product Chemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Yutaka Inoue
- Laboratory of Natural Product Chemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Youko Hasebe
- Laboratory of Cell Biology and Manipulation, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Masanori Okamoto
- Arid Land Research Center, Tottori University, Tottori, Japan PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Tsuyoshi Inukai
- Laboratory of Cell Biology and Manipulation, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Chikra Masuta
- Laboratory of Cell Biology and Manipulation, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Yasuko Sakihama
- Laboratory of Ecological Biochemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Yasuyuki Hashidoko
- Laboratory of Ecological Biochemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Mikiko Kojima
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
| | - Hitoshi Sakakibara
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
| | - Yasuyuki Inage
- Japan Agricultural Cooperatives Minami Sorachi, Kuriyama, Yubari-gun, Hokkaido, 069-1511 Japan
| | - Kosaku Takahashi
- Laboratory of Natural Product Chemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Teruhiko Yoshihara
- Laboratory of Natural Product Chemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
| | - Hideyuki Matsuura
- Laboratory of Natural Product Chemistry, Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan
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7
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Trisuwan K, Rukachaisirikul V, Sukpondma Y, Preedanon S, Phongpaichit S, Rungjindamai N, Sakayaroj J. Epoxydons and a pyrone from the marine-derived fungus Nigrospora sp. PSU-F5. JOURNAL OF NATURAL PRODUCTS 2008; 71:1323-1326. [PMID: 18646829 DOI: 10.1021/np8002595] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nigrospoxydons A-C (1- 3) and nigrosporapyrone (4), four new metabolites, were isolated from the marine-derived fungus Nigrospora sp. PSU-F5 together with nine known compounds. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. The antibacterial activity against the standard Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus was evaluated.
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Affiliation(s)
- Kongkiat Trisuwan
- Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand
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8
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Ueno K, Yoneyama H, Mizutani M, Hirai N, Todoroki Y. Asymmetrical ligand binding by abscisic acid 8′-hydroxylase. Bioorg Med Chem 2007; 15:6311-22. [PMID: 17582774 DOI: 10.1016/j.bmc.2007.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 06/04/2007] [Accepted: 06/05/2007] [Indexed: 11/24/2022]
Abstract
Abscisic acid (ABA), a plant stress hormone, has a chiral center (C1') in its molecule, yielding the enantiomers (1'S)-(+)-ABA and (1'R)-(-)-ABA during chemical synthesis. ABA 8'-hydroxylase (CYP707A), which is the major and key P450 enzyme in ABA catabolism in plants, catalyzes naturally occurring (1'S)-(+)-enantiomer, whereas it does not recognize naturally not occurring (1'R)-(-)-enantiomer as either a substrate or an inhibitor. Here we report a structural ABA analogue (AHI1), whose both enantiomers bind to recombinant Arabidopsis CYP707A3, in spite of stereo-structural similarity to ABA. The difference of AHI1 from ABA is the absence of the side-chain methyl group (C6) and lack of the alpha,beta-unsaturated carbonyl (C2'C3'-C4'O) in the six-membered ring. To explore which moiety is responsible for asymmetrical binding by CYP707A3, we synthesized and tested ABA analogues that lacked each moiety. Competitive inhibition was observed for the (1'R) enantiomers of these analogues in the potency order of (1'R,2'R)-(-)-2',3'-dihydro-4'-deoxo-ABA (K(I)=0.45 microM)>(1'R)-(-)-4'-oxo-ABA (K(I)=27 microM)>(1'R)-(-)-6-nor-ABA and (1'R,2'R)-(-)-2',3'-dihydro-ABA (no inhibition). In contrast to the (1'R)-enantiomers, the inhibition potency of the (1'S)-analogues declined with the saturation of the C2',C3'-double bond or with the elimination of the C4'-oxo moiety. These findings suggest that the C4'-oxo moiety coupled with the C2',C3'-double bond is the significant key functional group by which ABA 8'-hydroxylase distinguishes (1'S)-(+)-ABA from (1'R)-(-)-ABA.
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Affiliation(s)
- Kotomi Ueno
- The United Graduate School of Agricultural Science, Gifu University, Gifu 501-1193, Japan
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9
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Ueno K, Araki Y, Hirai N, Saito S, Mizutani M, Sakata K, Todoroki Y. Differences between the structural requirements for ABA 8'-hydroxylase inhibition and for ABA activity. Bioorg Med Chem 2005; 13:3359-70. [PMID: 15848748 DOI: 10.1016/j.bmc.2005.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 03/08/2005] [Accepted: 03/08/2005] [Indexed: 10/25/2022]
Abstract
A major catabolic enzyme of the plant hormone abscisic acid (ABA) is the cytochrome P450 monooxygenase ABA 8'-hydroxylase. For designing a specific inhibitor of this enzyme, the substrate specificity and inhibition of CYP707A3, an ABA 8'-hydroxylase from Arabidopsis thaliana, was investigated using 45 structural analogues of ABA and compared to the structural requirements for ABA activity. Substrate recognition by the enzyme strictly required the 6'-methyl groups (C-8' and C-9'), which were unnecessary for ABA activity, whereas elimination of the 3-methyl (C-6) and 1'-hydroxyl groups, which significantly affected ABA activity, had little effect on the ability of analogues to competitively inhibit the enzyme. Fluorination at C-8' and C-9' resulted in resistance to 8'-hydroxylation and competitive inhibition of the enzyme. In particular, 8',8'-difluoro-ABA and 9',9'-difluoro-ABA yielded no enzyme reaction products and strongly inhibited the enzyme (K(I) = 0.16 and 0.25 microM, respectively).
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Affiliation(s)
- Kotomi Ueno
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan
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10
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Abstract
The level of abscisic acid (ABA) in any particular tissue in a plant is determined by the rate of biosynthesis and catabolism of the hormone. Therefore, identifying all the genes involved in the metabolism is essential for a complete understanding of how this hormone directs plant growth and development. To date, almost all the biosynthetic genes have been identified through the isolation of auxotrophic mutants. On the other hand, among several ABA catabolic pathways, current genomic approaches revealed that Arabidopsis CYP707A genes encode ABA 8'-hydroxylases, which catalyze the first committed step in the predominant ABA catabolic pathway. Identification of ABA metabolic genes has revealed that multiple metabolic steps are differentially regulated to fine-tune the ABA level at both transcriptional and post-transcriptional levels. Furthermore, recent ongoing studies have given new insights into the regulation and site of ABA metabolism in relation to its physiological roles.
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Affiliation(s)
- Eiji Nambara
- Laboratory for Reproductive Growth Regulation, Plant Science Center, RIKEN, Yokohama, 230-0045, Japan.
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11
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Todoroki Y, Sawada M, Matsumoto M, Tsukada S, Ueno K, Isaka M, Owaki M, Hirai N. Metabolism of 5'alpha,8'-cycloabscisic acid, a highly potent and long-lasting abscisic acid analogue, in radish seedlings. Bioorg Med Chem 2004; 12:363-70. [PMID: 14723955 DOI: 10.1016/j.bmc.2003.10.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We synthesized 5'alpha,8'-cycloabscisic acid (CycloABA), a highly potent and long-lasting abscisic acid (ABA) analogue, by a different method from that reported before. CycloABA fed to radish seedlings had more metabolic tolerance than ABA. The major metabolite of CycloABA was the glucose conjugate, which was the minor metabolite of ABA. The 8'-hydroxylated metabolite and its cyclized isomer, which were major metabolites of ABA, were not found as metabolites of CycloABA. The present results suggest that the highly potent and long-lasting activity of CycloABA is caused by resistance to ABA 8'-hydroxylase, and that CycloABA is partially metabolized to the glucose conjugate by ABA glucosyltransferase.
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Affiliation(s)
- Yasushi Todoroki
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan.
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12
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Saito S, Hirai N, Matsumoto C, Ohigashi H, Ohta D, Sakata K, Mizutani M. Arabidopsis CYP707As encode (+)-abscisic acid 8'-hydroxylase, a key enzyme in the oxidative catabolism of abscisic acid. PLANT PHYSIOLOGY 2004; 134:1439-49. [PMID: 15064374 PMCID: PMC419820 DOI: 10.1104/pp.103.037614] [Citation(s) in RCA: 343] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Revised: 02/02/2004] [Accepted: 02/06/2004] [Indexed: 05/17/2023]
Abstract
Abscisic acid (ABA) is involved in a number of critical processes in normal growth and development as well as in adaptive responses to environmental stresses. For correct and accurate actions, a physiologically active ABA level is controlled through fine-tuning of de novo biosynthesis and catabolism. The hydroxylation at the 8'-position of ABA is known as the key step of ABA catabolism, and this reaction is catalyzed by ABA 8'-hydroxylase, a cytochrome P450. Here, we demonstrate CYP707As as the P450 responsible for the 8'-hydroxylation of (+)-ABA. First, all four CYP707A cDNAs were cloned from Arabidopsis and used for the production of the recombinant proteins in insect cells using a baculovirus system. The insect cells expressing CYP707A3 efficiently metabolized (+)-ABA to yield phaseic acid, the isomerized form of 8'-hydroxy-ABA. The microsomes from the insect cells exhibited very strong activity of 8'-hydroxylation of (+)-ABA (K(m) = 1.3 microm and k(cat) = 15 min(-1)). The solubilized CYP707A3 protein bound (+)-ABA with the binding constant K(s) = 3.5 microm, but did not bind (-)-ABA. Detailed analyses of the reaction products confirmed that CYP707A3 does not have the isomerization activity of 8'-hydroxy-ABA to phaseic acid. Further experiments revealed that Arabidopsis CYP707A1 and CYP707A4 also encode ABA 8'-hydroxylase. The transcripts of the CYP707A genes increased in response to salt, osmotic, and dehydration stresses as well as ABA. These results establish that the CYP707A family plays a key role in regulating the ABA level through the 8'-hydroxylation of (+)-ABA.
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Affiliation(s)
- Shigeki Saito
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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13
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Todoroki Y, Hirai N. Abscisic acid analogs for probing the mechanism of abscisic acid reception and inactivation. BIOACTIVE NATURAL PRODUCTS (PART H) 2002. [DOI: 10.1016/s1572-5995(02)80040-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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