The RING-Type Domain-Containing Protein GNL44 Is Essential for Grain Size and Quality in Rice ( Oryza sativa L.)

Grain size in rice ( L.) shapes yield and quality, but the underlying molecular mechanism is not fully understood. We functionally characterized ( ), encoding a RING-type protein that localizes to the cytoplasm. The mutant has fewer but enlarged grains compared to the wild type. is mainly expressed in panicles and developing grains. Grain chalkiness was higher in the mutant than in the wild type, short-chain amylopectin content was lower, middle-chain amylopectin content was higher, and appearance quality was worse. The amylose content and gel consistency of were lower, and protein content was higher compared to the wild type. Rapid Visco Analyzer results showed that the texture of cooked rice changed, and that the taste value of was lower, making the eating and cooking quality of worse than that of the wild type. We used , , and monogenic and two-gene near-isogenic lines to study the effects of different combinations of genes affecting grain size on rice quality-related traits. Our results revealed additive effects for these three genes on grain quality. These findings enrich the genetic resources available for rice breeders.