The Diversity of Starch Chain-length Distribution and Expression Analyses of Genes Related to Starch Biosynthesis in Japanese Landrace Rice Core Collection

Abstract

Rice starch is composed of linear amylose and branched amylopectin. The physicochemical properties of starch are influenced by amylose content and amylopectin structure. In this study, we examined the diversity of the chain length distribution of amylopectin among NIAS rice core collection of Japanese landraces, and compared the expression level of genes related to starch biosynthesis (starch synthase, branching enzyme and debranching enzyme). The measurement of the chain length distribution showed that Japonica varieties were mainly three types and more than half of them had high proportions of short chain length while the Indica species low proportions. The principal component analysis of the chain length distribution and gene expression level revealed that those with high short chain proportion were divided from other three groups with low short chain proportion. However, any tendency was not found to devide other three groups. It was suggested that there are some gene regulation pattern for starch synthesis among varieties with low short chain proportion.