title: OsJAR1 is required for JA-regulated floret opening and anther dehiscence in rice.
abstract: Jasmonates are important phytohormones regulating reproductive development. We used two recessive rice Tos17 alleles of OsJAR1, osjar1-2 and osjar1-3, to study the biological function of jasmonates in rice anthesis. The florets of both osjar1 alleles stayed open during anthesis because the lodicules, which control flower opening in rice, were not withering on time. Furthermore, dehiscence of the anthers filled with viable pollen, was impaired, resulting in lower fertility. In situ hybridization and promoter GUS transgenic analysis confirmed OsJAR1 expression in these floral tissues. Flower opening induced by exogenous applied methyl jasmonate was impaired in osjar1 plants and was restored in a complementation experiment with transgenics expressing a wild type copy of OsJAR1 controlled by a rice actin promoter. Biochemical analysis showed that OsJAR1 encoded an enzyme conjugating jasmonic acid (JA) to at least Ile, Leu, Met, Phe, Trp and Val and both osjar1 alleles had substantial reduction in content of JA-Ile, JA-Leu and JA-Val in florets. We conclude that OsJAR1 is a JA-amino acid synthetase that is required for optimal flower opening and closing and anther dehiscence in rice.
authors.affiliation: Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Xiao
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Charnikhova
authors.forename: Patrick P J
authors.initials: PP
authors.lastname: Mulder
authors.forename: Jeroen
authors.initials: J
authors.lastname: Heijmans
authors.forename: Angela
authors.initials: A
authors.lastname: Hoogenboom
authors.forename: Adamantia
authors.initials: A
authors.lastname: Agalou
authors.forename: Corinne
authors.initials: C
authors.lastname: Michel
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Morel
authors.forename: Ludovico
authors.initials: L
authors.lastname: Dreni
authors.forename: Martin M
authors.initials: MM
authors.lastname: Kater
authors.forename: Harro
authors.initials: H
authors.lastname: Bouwmeester
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhu
authors.forename: Pieter B F
authors.initials: PB
authors.lastname: Ouwerkerk
mesh_terms: D003517:Cyclopentanes / Q000494:pharmacology*; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D012275:Oryza / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D054883:Oxylipins / Q000494:pharmacology*; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000254:growth & development / Q000378:metabolism; D011058:Pollen / Q000502:physiology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C011006:jasmonic acid