Rice Papers

Genetics. 2009 Nov 23.

ERECT PANICAL2 Encodes a Novel Protein That Regulates Panicle Erectness in Indica Rice. <鏈帓鐗�>

绫肩ɑ涓皟鎺х鐩寸珛鐨勫熀鍥燛P2锛屽熀浜庣鐩寸珛鐨勪袱涓奔绋诲ぉ鐒剁獊鍙樹綋銆傜敓鐞嗗疄楠屻�佹瘮杈冨父瑙勭殑鍩哄洜鍥句綅鍏嬮殕銆�

Rice (Oryza sativa L.) inflorescence (panicle) architecture is an important agronomic trait for rice breeding. A number of high-yielding japonica rice strains, characterized by an erect panicle (EP) of their architecture, have been released as commercial varieties in China. But no EP-type indica varieties are released so far. Here, we identified two allelic erect-panicle mutants in indica rice, erect panicle2-1 (ep2-1) and erect panicle2-2 (ep2-2), exhibiting the characteristic erect panicle phenotype. Both mutants were derived from spontaneous mutation. We cloned the EP2 gene by way of a map-based cloning strategy, and transgenic complementation test rescued the phenotype of the ep2-1. Anatomical investigations revealed that the ep2 mutants have more vascular bundles and thicker stem than that of wild-type plants, explaining the panicle erectness phenotype in ep2 mutants. It was shown that the EP2 was specifically expressed in the vascular bundles of internodes by GUS staining and RT-PCR. The EP2 encodes a novel plant-specific protein, which localizes to the endoplasmic reticulum with unknown biochemical function. In addition, the EP2 also regulates other panicle characteristics, such as panicle length and grain size, but grain number of per panicle has little change, indicating that the mutation of ep2 gene could be applied in the EP-type indica rice breeding.