IDENTIFICATION OF METABOLITES AND DIFFERENTIALLY EXPRESSED GENES IN RICE Oryza sativa L. ‘KDML105’ OVEREXPRESSING OsCaM1-1

Abstract

OsCaM1-1-overexpressing rice (Oryza sativa L.) has been shown to gain salt stress-tolerant capability. In this study, cDNA-AFLP, GC-TOF/MS, and LC-MS/MS were performed to identify transcriptomic and metabolomic changes in the transgenic rice overexpressing OsCaM1-1. A total of 31 candidate genes being differentially expressed in the transgenic rice were identified by cDNA-AFLP. However, qRT-PCR analysis of 10 selected candidate genes did not show any significant different expression between the transgenic rice lines and wild type rice. From metabolomic data of transgenic rice and control transgenic rice, PLS-DA score plot and hierarchical clustering analysis indicated that OsCaM1-1 caused an alteration in transgenic rice metabolomes. Up-accumulation of many intermediates in energy metabolisms together with amino acids and tricin glucoside suggested that OsCaM1-1-overexpressing rice was induced to a proactive state. To investigate a metabolite-to-gene correlation, several candidate genes, e.g. arginase, glutathione synthetase, and inositol-1-monophosphatase, were selected based on the metabolome data. However, no differentially expressed genes were found, implying a possible post-translational regulation in those steps. Subsequent analyses of CaM binding site prediction and homology modeling suggested that one isoform of glutathione synthetase, and inositol-1-monophosphatase are potential CaM interacting partners. This study provides novel information about possible roles of OsCaM1-1.