Arabidopsis thaliana Rop GTPases are localized to tips of root hairs and control polar growth Journal Article


Author(s): Molendijk, Arthur J; Bischoff, Friedrich; Rajendrakumar, Chadalavada S; Friml, Jiří; Braun, Markus; Gilroy, Simon; Palme, Klaus
Article Title: Arabidopsis thaliana Rop GTPases are localized to tips of root hairs and control polar growth
Affiliation
Abstract: Plants contain a novel unique subfamily of Rho GTPases, vital components of cellular signalling networks. Here we report a general role for some members of this family in polarized plant growth processes. We show that Arabidopsis AtRop4 and AtRop6 encode functional GTPases with similar intrinsic GTP hydrolysis rates. We localized AtRop proteins in root meristem cells to the cross-wall and cell plate membranes. Polar localization of AtRops in trichoblasts specifies the growth sites for emerging root hairs. These sites were visible before budding and elongation of the Arabidopsis root hair when AtRops accumulated at their tips. Expression of constitutively active AtRop4 and AtRop6 mutant proteins in root hairs of transgenic Arabidopsis plants abolished polarized growth and delocalized the tip-focused Ca2+ gradient. Polar localization of AtRops was inhibited by brefeldin A, but not by other drugs such as latrunculin B, cytochalasin D or caffeine. Our results demonstrate a general function of AtRop GTPases in tip growth and in polar diffuse growth.
Keywords: Polarity; Arabidopsis thaliana; Rho GTPase; Root development; Root hair
Journal Title: EMBO Journal
Volume: 20
Issue 11
ISSN: 1460-2075
Publisher: Wiley-Blackwell  
Date Published: 2001-06-01
Start Page: 2779
End Page: 2788
URL:
DOI: 10.1093/emboj/20.11.2779
Open access: yes (repository)