title: Jasmonic acid control of GLABRA3 links inducible defense and trichome patterning in Arabidopsis.
abstract: Once attacked by herbivores, plants regenerate new leaves with increased trichome density as an inducible defense. Trichomes are specified from neighboring epidermal cells through local cell-cell interactions in the leaf primordia. However, the molecular mechanism of how herbivore-induced damage at older leaves remodels the pattern of trichome fate specification at newly forming leaves is largely unknown. In this study, we show that mutations in either the biosynthetic or signaling pathway of jasmonates (JAs), long-distance wound signals, abolish the wound-induced formation of trichomes. To identify the factors linking JA signaling to trichome fate specification, we isolated a novel class of mutants, unarmed (urm), which lack trichome induction but show otherwise normal responses to JAs. URM9 encodes an Importin beta family protein, and URM23 is identical to TRANSPARENT TESTA GLABRA1 (TTG1), the product of which interacts with the bHLH transcription factor GLABRA3 (GL3). Loss of either URM9 or URM23 disrupts the subnuclear localization of GL3, thus implicating GL3 in trichome induction. The expression of GL3 was enhanced by JA treatment prior to trichome initiation. Genetic analysis of multiple trichome mutants shows that GL3, in concert with the R2R3-Myb transcription factor GLABRA1 (GL1), promotes trichome fate in response to JA in a dosage-dependent manner. These results indicate that GL3 is a key transcription factor of wound-induced trichome formation acting downstream of JA signaling in Arabidopsis.
authors.affiliation: Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Sano
authors.forename: Takuji
authors.initials: T
authors.lastname: Wada
authors.forename: Junji
authors.initials: J
authors.lastname: Takabayashi
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Okada
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D003517:Cyclopentanes / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D054883:Oxylipins / Q000494:pharmacology*; D010641:Phenotype; D016415:Sequence Alignment
chemical_list: D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D003517:Cyclopentanes; D004268:DNA-Binding Proteins; D054883:Oxylipins; C417284:GL3 protein, Arabidopsis; C473611:MYC2 protein, Arabidopsis; C121067:TTG1 protein, Arabidopsis; C071556:GL1 protein, Arabidopsis; C011006:jasmonic acid