title: The IRREGULAR TRICHOME BRANCH loci regulate trichome elongation in Arabidopsis.
abstract: The proper control of cell expansion is vital to plant development. It is responsible for shaping individual cells and, together with cell division, it plays a lead role in shaping plant organs. Much of the underlying mechanism by which plant cells expand anisotropically is not understood. We are taking a genetic approach to cell expansion by isolating mutants that affect the branching pattern of Arabidopsis trichomes. Here we report the identification of four new loci that control trichome morphogenesis. These loci were named the IRREGULAR TRICHOME BRANCH (ITB) loci because of the deleterious effects on branch position and length in the mutants. Our analysis of branch expansion in itb mutants shows that the ITB genes act as positive regulators of branch elongation, and that the branch position defects are caused by altered expansion of the trichome stalk. The itb mutations display synergistic effects in double mutant combinations with certain branch number mutations, suggesting that the ITB genes also play key roles in branch initiation. These results demonstrate that the ITB genes are key regulators of anisotropic cell expansion in trichomes.
authors.affiliation: Department of Botany, University of Florida Genetics Institute, and the Plant Molecular and Cellular Biology Program, University of Florida, 220 Bartram Hall, PO Box 118526, Gainesville, FL 32611-8526, USA.
authors.forename: Xiaoguo
authors.initials: X
authors.lastname: Zhang
authors.forename: Paris H
authors.initials: PH
authors.lastname: Grey
authors.forename: Sujatha
authors.initials: S
authors.lastname: Krishnakumar
authors.forename: David G
authors.initials: DG
authors.lastname: Oppenheimer
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D017343:Genes, Plant; D009024:Morphogenesis; D009154:Mutation
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers