GNOM/FEWER ROOTS is required for the establishment of an auxin response maximum for arabidopsis lateral root initiation

Ken Ichi Okumura, Tatsuaki Goh, Koichi Toyokura, Hiroyuki Kasahara, Yumiko Takebayashi, Tetsuro Mimura, Yuji Kamiya, Hidehiro Fukaki

研究成果: Article同行評審

31 引文 斯高帕斯(Scopus)

摘要

Lateral root (LR) formation in vascular plants is regulated by auxin. The mechanisms of LR formation are not fully understood. Here, we have identified a novel recessive mutation in Arabidopsis thaliana, named fewer roots (fwr), that drastically reduces the number of LRs. Expression analyses of DR5::GUS, an auxin response reporter, and pLBD16::GUS, an LR initiation marker, suggested that FWR is necessary for the establishment of an auxin response maximum in LR initiation sites. We further identified that the fwr phenotypes are caused by a missense mutation in the GNOM gene, encoding an Arf-GEF (ADP ribosylation factor-GDP/GTP exchange factor), which regulates the recycling of PINs, the auxin efflux carriers. The fwr roots showed enhanced sensitivity to brefeldin A in a root growth inhibition assay, indicating that the fwr mutation reduces the Arf-GEF activity of GNOM. However, the other developmental processes except for LR formation appeared to be unaffected in the fwr mutant, indicating that fwr is a weaker allele of gnom compared with the other gnom alleles with pleiotropic phenotypes. The localization of PIN1-green fluorescent protein (GFP) appeared to be unaffected in the fwr roots but the levels of endogenous IAA were actually higher in the fwr roots than in the wild type. These results indicate that LR initiation is one of the most sensitive processes among GNOM-dependent developmental processes, strongly suggesting that GNOM is required for the establishment of the auxin response maximum for LR initiation, probably through the regulation of local and global auxin distribution in the root.

原文English
頁(從 - 到)406-417
頁數12
期刊Plant and Cell Physiology
54
發行號3
DOIs
出版狀態Published - 2013 3月

All Science Journal Classification (ASJC) codes

  • 生理學
  • 植物科學
  • 細胞生物學

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