An alternative,zeaxanthin epoxidase-independent abscisic acid biosynthetic pathway in plants  

作　　者：Kun-Peng Jia Jianing Mi Shawkat Ali Hajime Ohyanagi Juan C.Moreno Abdugaffor Ablazov Aparna Balakrishna Lamis Berqdar Alessia Fiore Gianfranco Diretto Claudio Martínez Angel R.de Lera Takashi Gojobori Salim Al-Babili 

机构地区：[1]Biological and Environmental Sciences and Engineering Division,Center for Desert Agriculture,The BioActives Lab,King Abdullah University of Science and Technology,Thuwal 23955-6900,Saudi Arabia [2]State Key Laboratory of Cotton Biology,Henan Joint International Laboratory for Crop Multi-Omics Research,School of Life Sciences,Henan University,Jinming Road,Kaifeng 475004,China [3]Biological and Environmental Sciences and Engineering Division,Computational Bioscience Research Center,King Abdullah University of Science and Technology,Thuwal 23955-6900,Saudi Arabia [4]Italian National Agency for New Technologies,Energy and Sustainable Economic Development,00123 Rome,Italy [5]Universidade de Vigo,Facultade de Química and CINBIO,36310 Vigo,Spain [6]Agriculture and Agri-Food Canada,Kentville Research and Development Center,32 Main Street,Kentville,NS B4N1J5,Canada

出　　处：《Molecular Plant》2022年第1期151-166,共16页分子植物（英文版）

基　　金：This work was supported by baseline funding and the Research Grants Prog ram-Round 4(CRG4);baseline funding from King Abdullah University of Science and Technology to S.A.-B.;National Natural Science Foundation of China(funds 31900245 and 32170271)given to K.-P.J.

摘　　要：Abscisic acid(ABA)is an important carotenoid-derived phytohormone that plays essential roles in plant response to biotic and abiotic stresses as well as in various physiological and developmental processes.In Arabidopsis,ABA biosynthesis starts with the epoxidation of zeaxanthin by the ABA DEFICIENT 1(ABA1)enzyme,leading to epoxycarotenoids;e.g.,violaxanthin.The oxidative cleavage of 9-cis-epoxycaro-tenoids,a key regulatory step catalyzed by 9-C/S-EPOXYCAROTENOID DIOXYGENASE,forms xanthoxin,which is converted in further rea.ctions mediated by ABA DEFICIENT 2(ABA2),ABA DEFICIENT 3(ABA3),and ABSCISIC ALDEHYDE OXIDASE 3(AAO3)into ABA.By combining genetic and biochemical approaches,we unravel here an ABA1-independent ABA biosynthetic pathway starting upstream of zeaxanthin.We iden-tified the carotenoid cleavage products(i.e.,apocarotenoids,β-apo-11-carotenal,9-cis-β-apo-11-carotenal,3-OH-β-apo-11-carotenal,and 9-cis-3-OH-β-apo-11-carotenal)as intermediates of this ABA1-independent ABA biosynthetic pathway.Using labeled compounds,we showed thatβ-apo-11-carotenal,9-cis-β-apo-11-carotenal,and 3-OH-β-apo-11-carotenal are successively converted into 9-cis-3-OH-β-apo-11-carotenal,xanthoxin,and finally into ABA in both Arabidopsis and rice.When applied to Arabidopsis,theseβ-apo-11-carotenoids exert ABA biological functions,such as maintaining seed dormancy and inducing the expression of ABA-responsive genes.Moreover,the transcdptomic analysis revealed a high overlap of differentially expressed genes regulated byβ-apo-11-carotenoids and ABA,suggesting thatβ-apo-11-carot-enoids exert ABA-independent regulatory activities.Taken together,our study identifies a biological function for the common plant metabolites,β-apo-11-carotenoids,extends our knowledge about ABA biosynthesis,and provides new insights into plant apocarotenoid metabolic networks.

关 键 词：seed germination APOCAROTENOIDS ABA ABA biosynthesis ABA1 carotenoids ultra-high-performance liquid chromatography-mass spectrometry Arabidopsis thaliana 

分 类 号：Q946[生物学—植物学]