The Regulation Mechanism Of Rice Root Growth And Development Mediated By OsRMC

We previously reported OsRAA1-overexpression resulted in phenotypes of reduced growth of primary root, increased number of adventitious roots and helix primary root, and delayed gravitropic response of roots in seedlings of rice. The OsRAA1 expression was induced by auxin. These data suggested that OsRAA1 as a new gene functions in the development of rice root systems, which is mediated by auxin. Recent studies in Arabidopsis about ubiquitin-related processes in phytohormonal signal transduction display that jasmonic acid and auxin signal transduction pathways are working via the 26S proteasome. But the michanism of jasmonic acid in development of rice root system is less known.Here we show that a receptor like protein OsRMC (Oryza sativa Root Meander and Curling, AAL87185) was down regulated in the roots of OsRAA1-overexprssion transgenic seedlings with two-dimensional PAGE (2-DE). The GST-OsRMC fusion protein was expressed in E. coli BL21 (DE3) cells. The inclusion body cut from gel was used to immunize rabbit for antibody. The result of western blot was accordant to of 2-DE.The OsRMC was isolated according to the sequence information of the gene in chromosome 4 with RT-PCR. Its predicted ORF encoded a 258 amino acid peptide. Sequence analysis in Genbank (http://www.ncbi.nlm.nih.gov) revealed the protein was belong to a domain unknown function 26 (DUF26) family of receptor-like kinases in plants. The OsRMC has one signal peptide and two C-X8-C-X2-C motifs (Cys-rich repeat, CRR), but has no transmembrane zone and kinase domain. OsRMC expression was detected in young spikes, young leaves, young shoots, stems and young roots by RT-PCR. In situ hybridization revealed that OsRMC expresses in root tips. OsRMC-GFP fusion study showed that OsRMC was a membrane binding protein. The results of western blotting proved that OsRMC was...