title: 12-oxo-phytodienoic acid accumulation during seed development represses seed germination in Arabidopsis.
abstract: Arabidopsis thaliana COMATOSE (CTS) encodes an ABC transporter involved in peroxisomal import of substrates for β-oxidation. Various cts alleles and mutants disrupted in steps of peroxisomal β-oxidation have previously been reported to exhibit a severe block on seed germination. Oxylipin analysis on cts, acyl CoA oxidase1 acyl CoA oxidase2 (acx1 acx2), and keto acyl thiolase2 dry seeds revealed that they contain elevated levels of 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), and JA-Ile. Oxylipin and transcriptomic analysis showed that accumulation of these oxylipins occurs during late seed maturation in cts. Analysis of double mutants generated by crossing cts with mutants in the JA biosynthesis pathway indicate that OPDA, rather than JA or JA-Ile, contributes to the block on germination in cts seeds. We found that OPDA was more effective at inhibiting wild-type germination than was JA and that this effect was independent of CORONATINE INSENSITIVE1 but was synergistic with abscisic acid (ABA). Consistent with this, OPDA treatment increased ABA INSENSITIVE5 protein abundance in a manner that parallels the inhibitory effect of OPDA and OPDA+ABA on seed germination. These results demonstrate that OPDA acts along with ABA to regulate seed germination in Arabidopsis.
authors.affiliation: Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO105DD, United Kingdom.
authors.forename: Anuja
authors.initials: A
authors.lastname: Dave
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Hernández
authors.forename: Zhesi
authors.initials: Z
authors.lastname: He
authors.forename: Vasilios M E
authors.initials: VM
authors.lastname: Andriotis
authors.forename: Fabián E
authors.initials: FE
authors.lastname: Vaistij
authors.forename: Tony R
authors.initials: TR
authors.lastname: Larson
authors.forename: Ian A
authors.initials: IA
authors.lastname: Graham
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D003517:Cyclopentanes / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000187:drug effects*; D009154:Mutation; D054883:Oxylipins / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000254:growth & development*
chemical_list: D003517:Cyclopentanes; D005231:Fatty Acids, Unsaturated; D054883:Oxylipins; C025999:12-oxophytodienoic acid; C011006:jasmonic acid; D000040:Abscisic Acid