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OsAGAP , an ARF‐GAP from rice, regulates root development mediated by auxin in Arabidopsis
Author(s) -
ZHUANG X.,
XU Y.,
CHONG K.,
LAN L.,
XUE Y.,
XU Z.
Publication year - 2005
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2004.01253.x
Subject(s) - arabidopsis , auxin , gtpase , biology , microbiology and biotechnology , mutant , guanine nucleotide exchange factor , adp ribosylation factor , arabidopsis thaliana , polar auxin transport , genetically modified rice , small gtpase , botany , apical dominance , oryza sativa , transgene , gtpase activating protein , root hair , shoot , gene , biochemistry , genetically modified crops , g protein , signal transduction , golgi apparatus , endoplasmic reticulum
Arf (ADP‐ribosylation factor) proteins, which mediate vesicular transport, have little or no intrinsic GTPase activity. They rely on the action of GTPase‐activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs) for their function. In the present study the OsAGAP gene in rice, which encoded a protein with predicted structure similar to ArfGAP, was identified. The purified OsAGAP‐GST fusion protein was able to stimulate the GTPase activity of rice Arf. Furthermore, OsAGAP can rescue the defect of vesicular transport in the yeast gcs1 Δ glo3 Δ double‐mutant cells. Transgenic Arabidopsis with OsAGAP constitutively expression showed reduced apical dominance, shorter primary roots, increasing number of longer adventitious roots. Many of the phenotypes can be phenocopied by treatment of exogenous indoleacetic acid level (IAA) in wild‐type plants. Determination of whole‐plant IAA level showed that there is a sharp increase of free IAA in OsAGAP transgenic Arabidopsis seedlings. In addition, removal of the 4‐day‐old shoot apex could inhibit the adventitious root formation in the transgenic seedlings. These results suggest OsAGAP, an ARF‐GAP of rice, may be involved in the mediation of plant root development by regulating auxin level.