Genetic and epigenetic regulatory mechanism of rice panicle development

Rice panicle architecture is a key agronomical trait that directly contributes to grain productivity. The complexity of the developmental process of the young panicle determines the complexity of its regulatory molecular mechanism. This paper briefly introduces the general process of panicle development and summarizes the important genes/quantitative trait loci regulating panicle development, identified and characterized by mutant screening and map cloning in recent years. According to their roles in the rice panicle development process, these genes are divided into 3 categories: initiation and maintenance of axillary meristems, size of meristem, and elongation of the branches. In recent years, knowledge on the epigenetic regulatory mechanism of panicle development has improved. In addition, development of the young panicle has been confirmed to be closely related to the regulation of plant hormones. Finally, the new genome editing tool clustered regularly interspaced short palindromic repeats/associated protein-9 nuclease and epigenome-wide association studies are expected to contribute to further understand the molecular mechanisms of panicle development, which might help improving panicle traits for increasing grain yield.