Functional Analysis of RERJ1, a Jasmonic Acid-responsive Transcription Factor From Rice

Abstract

Jasmonic acid (JA) is a plant hormone that acts as a secondary signal molecule in plant defense against pathogens. RERJ1 which encodes a bHLH transcription factor was isolated as a JA-early-responsive gene from suspension-cultured rice cells, and candidate target genes of RERJ1 were suveyed by microarray analysis of transformants overexpressing RERJ1. In the present study, we generated a transgenic rice (XS-line) in which RERJ1 expression could be induced by estradiol treatment. Expression of RERJ1 in the XS-line under 1 mM estradiol treatment was almost equal to that after 0.1 mM JA treatment. Now, we are investigating relationships between expression of RERJ1 and that of the candidate target gene by expression analysis and reporter-gene assay using XS-line in a time-dependent manner after RERJ1 expression. We also suggested by transient gene expression assays that RERJ1 functions as an transcriptional activator of target genes in vivo.