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Arabidopsis thaliana Rop GTPases are localized to tips of root hairs and control polar growth
Author(s) -
Molendijk Arthur J,
Bischoff Friedrich,
Rajendrakumar Chadalavada S V,
Friml Jiří,
Braun Markus,
Gilroy Simon,
Palme Klaus
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.11.2779
Subject(s) - root hair , biology , gtpase , arabidopsis , tip growth , arabidopsis thaliana , microbiology and biotechnology , meristem , cell plate , cell polarity , botany , mutant , biochemistry , cell division , cytokinesis , cell , gene , pollen , pollination , pollen tube
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 Ca 2+ 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.