Identification of Genes and miRNAs Affecting Pre-harvest Sprouting in Rice (Oryza sativa L.) by Transcriptome and Small RNAome Analyses

Purpose: The goal of our study is to compare two different ecotypes of Oryza sativa L., PHS-susceptible rice trait and PHS-resistant rice trait under three different maturation stages and two different tissues, embryo and endosperm of rice seeds with profile of RNA-seq. Methods: Oryza sativa. L mRNA profiles of two different ecotypes with 3 different maturation stages and 2 different tissues were generated by NGS, in duplicate, following Illumina NGS workflow. qRT–PCR validation was performed using SYBR Green assays. Results: We found the differentially expressed genes (DEGs) between PHS-susceptible rice trait and PHS-resistant rice trait according to the three different seed maturation stages. In DEGs, gene ontology (GO) analysis and Mapman analysis were performed, and we discovered genes related to plant hormones and heat stress, which are not yet reported. These genes were validated through qRT-PCR, and it is likely to be highly related to seed dormancy. Conclusions: Our study represents the analysis of rice seed transcriptomes under two different ecotypes, three different seed maturation stages and two different tissues (Embryo and endosperm). Our results show that seed dormancy is affected and regulated by a plant hormones and heat stress. This study might provide a foundation for understanding dynamics of seed dormancy during the seed development and overcoming pre-harvest sprouting. Overall design: mRNA profiles of two different ecotypes of rice (Oryza sativa L.)