Comprehensive Expression Analysis of Rice Armadillo Gene Family During Abiotic Stress and Development

Genes in the Armadillo (ARM)-repeat superfamily encode proteins with a range of developmental and physiological processes in unicellular and multicellular eukaryotes. These 42 amino acid, long tandem repeat-containing proteins have been abundantly recognized in many plant species. Previous studies have confirmed that Armadillo proteins constitute amultigene family in Arabidopsis. In this study, we performed a computational analysis in the rice genome (Oryza sativa L. subsp. japonica), and identified 158 genes of Armadillo superfamily. Phylogenetic study classified them into several arbitrary groups based on a varying numberof non-conservedARM repeats and accessory domain(s) associatedwith them. An in-depth analysis of geneexpression throughmicroarrayandQ-PCRrevealedanumberofARMproteinsexpressingdifferential-ly in abiotic stresses and developmental conditions, suggesting a potential roles of this superfamily in devel-opment and stress signalling. Comparative phylogenetic analysis between Arabidopsis and rice Armadillo genes revealed a high degree of evolutionary conservation between the orthologues in two plant species. Thenon-synonymous and synonymous substitutions per site ratios (Ka/Ks) of duplicated genepairs indicate a purifying selection. This genome-wide identification and expression analysis provides a basis for further functional analysis of Armadillo genes under abiotic stress and reproductive developmental condition in the plant lineage. Key words: Armadillo; abiotic stress; development; signal transduction 1