Comparative Transcriptomic Analysis of Two Rice (Oryza sativa L.) Male Sterile Line Seed Embryos Under Accelerated Aging

Abstract

Seed aging is a complex and irreversible process during seed development and storage. The quality of parental seeds affects yield and quality of hybrid rice seeds directly. However, little is known about the mechanism of the accelerated aging seeds in hybrid rice photoperiod-thermo-sensitive genic male sterile (PTGMS) lines. RNA-Seq technique was performed by using seed embryos of two PTGMS lines, Y58S (YS) and Zhun S (ZS), under the restrictive conditions (95% relative humidity and 45 °C) for 0 day, 5 days, 7 days, and 10 days. In total, 1198, 487, 1308, 396, and 669 differentially expressed genes (DEGs) were identified between adjacent time periods of accelerated aging treatment in the ZS and YS. Gene Ontology (GO) analysis revealed the DEGs enriched in the starch catabolic process and sucrose catabolic process. It also showed that many genes were enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways such as starch and sucrose metabolism, plant-pathogen interaction, and plant hormone signal transduction. In addition, 34 candidate genes were selected to the following phylogenetic analysis and different gene expression profiles. Finally, several key candidate genes of seed aging were identified, containing a rice sucrose synthase Os07g0616800 and an unknown gene Os12g0161500, by quantitative real-time PCR. Together, these results established a good foundation for studying the molecular mechanism of rice seed storability and also provide new insights into the PTMGS line seed storage.