title: A gain-of-function mutation in IAA16 confers reduced responses to auxin and abscisic acid and impedes plant growth and fertility.
abstract: Auxin regulates many aspects of plant development, in part, through degradation of the Aux/IAA family of transcriptional repressors. Consequently, stabilizing mutations in several Aux/IAA proteins confer reduced auxin responsiveness. However, of the 29 apparent Aux/IAA proteins in Arabidopsis thaliana, fewer than half have roles established through mutant analysis. We identified iaa16-1, a dominant gain-of-function mutation in IAA16 (At3g04730), in a novel screen for reduced root responsiveness to abscisic acid. The iaa16-1 mutation also confers dramatically reduced auxin responses in a variety of assays, markedly restricts growth of adult plants, and abolishes fertility when homozygous. We compared iaa16-1 phenotypes with those of dominant mutants defective in the closely related IAA7/AXR2, IAA14/SLR, and IAA17/AXR3, along with the more distantly related IAA28, and found overlapping but distinct patterns of developmental defects. The identification and characterization of iaa16-1 provides a fuller understanding of the IAA7/IAA14/IAA16/IAA17 clade of Aux/IAA proteins and the diverse roles of these repressors in hormone response and plant development.
authors.affiliation: Department of Biochemistry and Cell Biology, Rice University, Houston, TX, 77005, USA.
authors.forename: Mauro A
authors.initials: MA
authors.lastname: Rinaldi
authors.forename: James
authors.initials: J
authors.lastname: Liu
authors.forename: Tara A
authors.initials: TA
authors.lastname: Enders
authors.forename: Bonnie
authors.initials: B
authors.lastname: Bartel
authors.forename: Lucia C
authors.initials: LC
authors.lastname: Strader
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics; D005298:Fertility / Q000187:drug effects / Q000235:genetics; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000494:pharmacology; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D000040:Abscisic Acid