title: Identification of the OsOPR7 gene encoding 12-oxophytodienoate reductase involved in the biosynthesis of jasmonic acid in rice.
abstract: Enzyme 12-oxophytodienoate (OPDA) reductase (EC1.3.1.42), which is involved in the biosynthesis of jasmonic acid (JA), catalyses the reduction of 10, 11-double bonds of OPDA to yield 3-oxo-2-(2'-pentenyl)-cyclopentane-1-octanoic acid (OPC-8:0). The rice OsOPR1 gene encodes OPDA reductase (OPR) converting (-)-cis-OPDA preferentially, rather than (+)-cis-OPDA, a natural precursor of JA. Here, we provide evidence that an OPR family gene in rice chromosome 8, designated OsOPR7, encodes the enzyme involved in the JA biosynthesis. Recombinant OsOPR7-His protein efficiently catalysed the reduction of both enantiomers of cis-OPDA, similar to the OPR3 protein in Arabidopsis thaliana (L.) Heynh. The expression of OsOPR7 mRNA was induced and reached maximum levels within 0.5 h of mechanical wounding and drought stress, and the endogenous JA level started to increase in accordance with the increase in OsOPR7 expression. The GFP-OsOPR7 fusion protein was detected exclusively in peroxisomes in onion epidermal cells. Furthermore, complementation analysis using an Arabidopsis opr3 mutant indicated that the OsOPR7 gene, but not OsOPR1, was able to complement the phenotypes of male sterility in the mutant caused by JA deficiency, and that JA production in the opr3 mutant was also restored by the expression of the OsOPR7 gene. We conclude that the OsOPR7 gene encodes the enzyme catalysing the reduction of natural (+)-cis-OPDA for the JA biosynthesis in rice.
authors.affiliation: Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Tani
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sobajima
authors.forename: Kazunori
authors.initials: K
authors.lastname: Okada
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Chujo
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Arimura
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tsutsumi
authors.forename: Mikio
authors.initials: M
authors.lastname: Nishimura
authors.forename: Hideharu
authors.initials: H
authors.lastname: Seto
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nojiri
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Yamane
mesh_terms: D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics; D003517:Cyclopentanes / Q000378:metabolism*; D015870:Gene Expression; D005816:Genetic Complementation Test; D012275:Oryza / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D010088:Oxidoreductases / Q000235:genetics; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics* / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D020675:Peroxisomes / Q000378:metabolism*; D051479:Plant Infertility / Q000502:physiology; D018515:Plant Leaves / Q000378:metabolism; D013237:Stereoisomerism; D014867:Water / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D014867:Water; C011006:jasmonic acid; C416525:OPR3 protein, Arabidopsis; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C106360:12-oxophytodienoate reductase