Comparative Transcriptomic Analysis in Paddy Rice under Storage and Identification of Differentially Regulated Genes in Response to High Temperature and Humidity

The transcriptomes of paddy rice in response to high temperature and humidity were studied using a high throughput RNA sequencing approach. Effects of high temperature and humidity on the sucrose and starch contents and beta-amylase activity were also investigated. Results showed that 6876 differentially expressed genes (DEGs) were identified in paddy rice under high temperature and humidity storage. Importantly, 12 DEGs that were downregulated fell into the "starch and sucrose pathway". The quantitative real-time polymerase chain reaction assays indicated that expression of these 12 DEGs was significantly decreased, which was in parallel with the reduced level of enzyme activities and the contents of sucrose and starch in paddy rice stored at high temperature and humidity conditions compared to the control group. Taken together, high temperature and humidity influence the quality of paddy rice at least partially by downregulating the expression of genes encoding sucrose transferases and hydrolases, which might result in the decrease of starch and sucrose contents.