title: The hydroperoxide lyase branch of the oxylipin pathway protects against photoinhibition of photosynthesis.
abstract: This study describes a new role for hydroperoxide lyase branch of oxylipin biosynthesis pathway in protecting photosynthetic apparatus under high light conditions. Lipid-derived signaling molecules, oxylipins, produced by a multi-branch pathway are central in regulation of a wide range of functions. The two most known branches, allene oxide synthase (AOS) and 13-hydroperoxide lyase (HPL) pathways, are best recognized as producers of defense compounds against biotic challenges. In the present work, we examine the role of these two oxylipin branches in plant tolerance to the abiotic stress, namely excessive light. Towards this goal, we have analyzed variable chlorophyll fluorescence parameters of intact leaves of Arabidopsis thaliana genotypes with altered oxylipin profile, followed by examining the impact of exogenous application of selected oxylipins on functional activity of photosynthetic apparatus in intact leaves and isolated thylakoid membranes. Our findings unequivocally bridge the function of oxylipins to photosynthetic processes. Specifically, HPL overexpressing lines display enhanced adaptability in response to high light treatment as evidenced by lower rate constant of photosystem 2 (PS2) photoinhibition and higher rate constant of PS2 recovery after photoinhibition. In addition, exogenous application of linolenic acid, 13-hydroperoxy linolenic acid, 12-oxophytodienoic acid, and methyl jasmonate individually, suppresses photochemical activity of PS2 in intact plants and isolated thylakoid membranes, while application of HPL-branch metabolites-does not. Collectively these data implicate function of HPL branch of oxylipin biosynthesis pathway in guarding PS2 under high light conditions, potentially exerted through tight regulation of free linolenic acid and 13-hydroperoxy linolenic acid levels, as well as competition with production of metabolites by AOS-branch of the oxylipin pathway.
authors.affiliation: Institute of Basic Biological Problems, RAS, Institutskaya st., 2, Pushchino, 142290, Moscow Region, Russia. savchenko_t@rambler.ru.|All-Russian Research Institute of Phytopathology, Institute st., 5, Odintsovo District, B. Vyazyomy, 143050, Moscow Region, Russia. savchenko_t@rambler.ru.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Savchenko
authors.affiliation: Institute of Basic Biological Problems, RAS, Institutskaya st., 2, Pushchino, 142290, Moscow Region, Russia.|All-Russian Research Institute of Phytopathology, Institute st., 5, Odintsovo District, B. Vyazyomy, 143050, Moscow Region, Russia.
authors.forename: Denis
authors.initials: D
authors.lastname: Yanykin
authors.affiliation: Institute of Basic Biological Problems, RAS, Institutskaya st., 2, Pushchino, 142290, Moscow Region, Russia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Khorobrykh
authors.affiliation: Institute of Basic Biological Problems, RAS, Institutskaya st., 2, Pushchino, 142290, Moscow Region, Russia.
authors.forename: Vasily
authors.initials: V
authors.lastname: Terentyev
authors.affiliation: Institute of Basic Biological Problems, RAS, Institutskaya st., 2, Pushchino, 142290, Moscow Region, Russia.
authors.forename: Vyacheslav
authors.initials: V
authors.lastname: Klimov
authors.affiliation: Institute for Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA.
authors.forename: Katayoon
authors.initials: K
authors.lastname: Dehesh
mesh_terms: D000085:Acetates / Q000378:metabolism; D000446:Aldehyde-Lyases / Q000378:metabolism; D017360:Arabidopsis / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D008027:Light; D054883:Oxylipins / Q000378:metabolism*; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism; D017962:alpha-Linolenic Acid / Q000378:metabolism
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D054883:Oxylipins; D045332:Photosystem II Protein Complex; D017962:alpha-Linolenic Acid; C072239:methyl jasmonate; D003577:Cytochrome P-450 Enzyme System; D000446:Aldehyde-Lyases; C054540:hydroperoxide lyase; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase
keywords: Allene oxide synthase; High light stress; Hydroperoxide lyase; Oxylipins; Photoinhibition; Photosystem 2