Genetic Control of Inflorescence Architecture during Rice Domestication

Inflorescence architecture is a key agronomical factor determining grain yield and thus has been a major target of cereal crop domestication. The transition from a spread panicle typical of ancestral wild rice (Oryza rufipogon Griff.) to the compact panicle of present cultivars (O. sativa L.) was a crucial event in rice domestication. Here, we show that the spread panicle architecture of wild rice is controlled by a single dominant gene, which was designated PAC1 (Panicle Architecture Control 1). Positional cloningof the gene revealed that PAC1 was corresponded to LG1, which controls laminar joint and ligule development. Association analysis indicates that a single nucleotide polymorphism (SNP6), residing in the regulatory region 11 kb upstream of the PAC1/LG1 gene,  led to a compact panicle architecture in cultivars during rice domestication. It is speculated that cis-regulatory mutation can fine-tune the spatial expression of the target gene, and selection of cis-regulatory mutation might be an efficient strategy for crop domestication and improvement.