Genome-wide transcriptome comparison of flag leaves among japonica and indica varieties

摘要

Flag leaves in crops are one of the key organs determining grain yield, which significantly affects total yield. However, our understanding of the molecular and genetic regulation of flag leaves is very limited. To provide a genome-wide view of gene expression in flag leaves associated with grain yield, we compared the flag leaves of rice varieties with different yield potentials, such as Hwacheong (moderate yield), Milyang23 (high yield), Dasan (high yield), and IR64 (high yield), using an Agilent 8x60K microarray. As a result, we identified 245 genes that were up-regulated in high yield potential varieties compared to Hwacheong, along with 293 genes that were up-regulated in Hwacheong. GO enrichment analysis of the selected candidate genes revealed that the thiamin biosynthetic process and the sucrose metabolic process were the most enriched terms in flag leaves from the high yield potential varieties, while phosphate transport and the chitin catabolic process terms were the most significant in flag leaves of Hwacheong. In addition, MapMan analysis suggested that the biotic stress response and auxin signaling are important in Hwacheong, while the heat stress response, calcium and G-protein signaling are necessary in other high yield potential varieties. The functions of 11 of our candidate genes have been previously characterized in genetic and molecular biological studies and most of them are related to tolerance against environmental challenges or yield, thereby indicating the potential significance of our candidate genes in further applications.