Functional Analysis of The Jasmonate-Responsive Gene RERJ1 in Rice

Abstract

Jasmonic acid (JA) is a plant hormone which regulates various developmental processes in plants, and it acts as a signal molecule in plant defense against herbivores and pathogens. We isolated a cDNA for the JA-responsive gene RERJ1 from suspension-cultured rice cells. RERJ1 encodes a transcriptional regulator with a bHLH motif. Analyses of the phenotypes of rice plants expressing sense- and antisense-RERJ1 mRNA strongly suggested that RERJ1 is involved in the inhibition of shoot growth caused by exogenously applied JA. However, the other biological functions of RERJ1 remain to be clarified. In this study, it was indicated that in rice plants RERJ1 was upregulated by exposure to stresses such as wounding, salt, and drought as well as JA, but that RERJ1 was not responsive to abscisic acid. We also carried out microarray analysis using RNA from sense-RERJ1-overexpressing rice calli to survey the target genes of RERJ1.