GNS4, a novel allele of DWARF11, regulates grain number and grain size in a high-yield rice variety
会议名称：《江苏省遗传学会2017年学术研讨会——“技术创新与遗传学发展”》
会议日期：2017年
关 键 词：Rice GNS4/D11 Grain number Grain size Cell elongation
摘 要：Rice plays an extremely important role in food safety because it feeds more than half of the world’s population. Rice grain yield depends on biomass and the harvest index. An important strategy to break through the rice grain yield ceiling is to increase the biological yield. Therefore, genes associated with organ size are important targets for rice breeding. We characterized a rice mutant gns4(grain number and size on chromosome 4) with reduced organ size, fewer grains per panicle, and smaller grains compared with those of WT. Mapbased cloning indicated that the GNS4 gene, encoding a cytochrome P450 protein, is a novel allele of DWARF11(D11). A single nucleotide polymorphism(deletion) in the promoter region of GNS4 reduced its expression level in the mutant, leading to reduced grain number and smaller grains. Morphological and cellular analyses suggested that GNS4 positively regulates grain size by promoting cell elongation. Overexpression of GNS4 significantly increased organ size, 1000-grain weight, and panicle size, and subsequently enhanced grain yields in both the Nipponbare and Wuyunjing7(a high-yielding cultivar) backgrounds. These results suggest that GNS4 is key target site with possible applications in rice yield breeding. GNS4 was identified as a positive regulator of grain number and grain size in rice. Increasing the expression level of this gene in a high-yielding rice variety enhanced grain yield. GNS4 can be targeted in breeding programs to increase yields.