| Abstract Detail
Cell-to-Cell and Long Distance Signaling Chevalier, Eric [1], Matton, Daniel P. [2]. RALF, a secreted peptide involved in plant reproduction. Small secreted peptides have been shown to be involved in intercellular signaling in numerous physiological processes including self-incompatibility, pathogen recognition, cell differentiation and cell growth. Most have been shown to act through a receptor-mediated pathway, suggesting a common theme in the recognition process at the plasma membrane. The Rapid Alkalinization Factor or RALF, is a 5 kDa peptide initially isolated from tobacco and showed to play a role in development by inhibiting cell growth. In Solanum chacoense, we have isolated 5 RALF-like genes, of which 2 were predominantly expressed in reproductive tissues. RNAi lines of ScRALF1 were shown to have impaired fruit growth. In Arabidopsis thaliana, there are 36 RALF-like genes. Single T-DNA insertional mutants were analyzed in Arabidopsis for the 2 putative ScRALF1 orthologs (AtRALF-like 24 and 31) and no obvious phenotype was observed. Although these genes are expressed in female reproductive tissues, they are also ubiquitously expressed. Gene redundancy in the RALF family and overlapping expression patterns could explain this absence of visible phenotype. However, using publicly available microarray data, five other Arabidopsis RALF-like genes were found to be highly specific to reproductive tissues, especially stamen and pollen. Fine expression analysis is currently being conducted on these genes through promoter:GUS reporter gene assays. Functional analysis of these genes is also currently being done in T-DNA insertional mutants or RNAi lines. Using various RALF:GFP fusion proteins we also show by fluorescence microscopy and western blotting that, following the initial signal peptide cleavage, N-terminal processing of the proRALF peptide to the mature RALF protein occurs in the cis-golgi compartment.
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1 - Université de Montréal (IRBV), Sciences Biologiques, 4101, rue Sherbrooke Est, Montréal, QC, H1X 2B2, Canada
2 - Université de Montréal (IRBV), Sciences Biologiques
Keywords:
Rapid Alcalinization Factor
RALF
gene expression.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P34002
Abstract ID:341 |
