Abstract
The regulation of seed size in rice represents a significant concern within the domain of developmental biology. Nevertheless, our understanding of the mechanisms by which plants determine seed size remains limited, despite its critical importance. The transcriptome and proteome sequencing of rice kernels, derived from the recombinant inbred line (RIL) population between the large-grain line AD3 and the small-grain line AD148, were conducted at the third stage of spikelet development (stage Sp 3: formation of lemma primordium), the sixth stage of spikelet development (stage Sp 6: formation of stamen primordia), as well as nine days post anthesis (9DPA). During the stage Sp 3 and stage Sp 6, the differentially expressed genes were predominantly associated with metabolic pathways, secondary metabolite synthesis, and nitrogen metabolism. In contrast, at 9DPA, these genes were primarily involved in cysteine and methionine metabolism, biosynthesis, and protein processing. This observation indicates that the differences in grain size between the large-grain line AD3 and the small-grain line AD148 result from distinct biological processes occurring both during the early stages of glume development and the grain filling stage. Furthermore, eight genes have been identified as potential regulators of grain development, providing valuable information on the underlying mechanisms of grain development in rice.To identify the key genes, pathways, and regulatory networks controlling rice grain size by integrating transcriptomic and proteomic analyses of large-grain (AD3) and small-grain (AD148) lines at critical developmental stages.