title: ArabidopsisMyosins XI1, XI2, and XIK Are Crucial for Gravity-Induced Bending of Inflorescence Stems.
abstract: Myosins and actin filaments in the actomyosin system act in concert in regulating cell structure and dynamics and are also assumed to contribute to plant gravitropic response. To investigate the role of the actomyosin system in the inflorescence stem gravitropism, we used single and multiple mutants affecting each of the 17Arabidopsismyosins of class VIII and XI. We show that class XI but not class VIII myosins are required for stem gravitropism. Simultaneous loss of function of myosins XI1, XI2, and XIK leads to impaired gravitropic bending that is correlated with altered growth, stiffness, and insufficient sedimentation of gravity sensing amyloplasts in stem endodermal cells. The gravitropic defect of the corresponding triple mutantxi1 xi2 xikcould be rescued by stable expression of the functional XIK:YFP in the mutant background, indicating a role of class XI myosins in this process. Altogether, our results emphasize the critical contributions of myosins XI in stem gravitropism ofArabidopsis.
authors.affiliation: Department of Gene Technology, Tallinn University of Technology Tallinn, Estonia.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Talts
authors.affiliation: Department of Gene Technology, Tallinn University of Technology Tallinn, Estonia.
authors.forename: Birger
authors.initials: B
authors.lastname: Ilau
authors.affiliation: Department of Gene Technology, Tallinn University of Technology Tallinn, Estonia.
authors.forename: Eve-Ly
authors.initials: EL
authors.lastname: Ojangu
authors.affiliation: Department of Gene Technology, Tallinn University of Technology Tallinn, Estonia.
authors.forename: Krista
authors.initials: K
authors.lastname: Tanner
authors.affiliation: Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis OR, USA.
authors.forename: Valera V
authors.initials: VV
authors.lastname: Peremyslov
authors.affiliation: Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis OR, USA.
authors.forename: Valerian V
authors.initials: VV
authors.lastname: Dolja
authors.affiliation: Department of Gene Technology, Tallinn University of Technology Tallinn, Estonia.
authors.forename: Erkki
authors.initials: E
authors.lastname: Truve
authors.affiliation: Department of Gene Technology, Tallinn University of Technology Tallinn, Estonia.
authors.forename: Heiti
authors.initials: H
authors.lastname: Paves
keywords: Arabidopsis; T-DNA mutants; actin filaments; amyloplasts; gravitropism; myosins