Abstract
High temperature during the grain-filling stage causes deleterious effects on rice quality. In this study, we performed the screening of rice plants revealed decreased production of chalky grain by high temperature using many kinds of gene-suppressed rice plants. Three kinds of gene-suppressed plants were found as one revealed decreased production of chalky grain by high temperature. Biochemical analysis of starch showed that the high-temperature-ripened grains of the wild-type plants containing decreased levels of amylose of a specific size (DP=9-14), whereas those of the three kinds of gene-suppressed plants containing decreased levels of one (DP=13-18). Comprehensive gene screening by a 44-K DNA microarray in the grains during the grain-filling stage revealed that several genes which are involved in the scavenging of reactive oxygen species (ROS) such as superoxide dismutase (SOD) and catalase were up-regulated in the three plants compared with the wild-type plants. The relationship between these results and the production of chalky grain by high temperature was discussed.
