Modulation of rice grain shape and appearance by the GS10-encoded long coiled-coil protein

Rice grain size is a primary characteristic essential for artificial domestication and breeding, governed by grain length, width, and thickness. In this study, we cloned Grain Size 10 (GS10), a novel gene via map-based cloning. Biochemical, molecular, and genetic studies were performed to elucidate the GS10 involved grain size mechanism in rice. Mutant of GS10 lead to reduced grain size due to alterations in cell expansion. Additionally, GS10 is responsible for the formation of notched-belly grains, especially in smaller grain varieties possessing loss-function mutations. Overexpression of GS10 in Nipponbare results in increasing grain length, grain weight and improve the appearance quality of rice. GS10 encodes conserved protein with uncharacterized function. Furthermore, GS10 regulates the grain size by interacting OsBRICK1, a subunit of the WAVE complex that governs actin nucleation and affects the assembly of microfilaments in rice. Together, our study demonstrates that, GS10 positively regulates the grain length and grain weight, which is beneficial for further improvements in yield characteristics.