Abstract
To investigate influence on rice grain-filling metabolism by high temperature, the comprehensive expression analysis using microarray and conventional differential screening was conducted. The kernel grown under high temperature condition (33/28 C) had decreased grain weight and milky-white appearance compared to the control grown under low temperature (25/20 C). Starch analyses revealed that high temperature-grown kernel has lower amylose content and altered amylopectin which is rich in long chains (DP 20-32) and poor in short chains (DP 6-18). Microarray analysis using developing seeds 10d after anthesis revealed that expression of granule-bound starch synthase (GBSSI) and starch branching enzyme (BEIIb) genes was repressed under high temperature, which is in agreement with change of starch composition; decrease of amylose content and elongation of side-chains of amylopectin. These results suggest that storage material in rice kernel is, in part, controlled by gene expression level.
