Grain weight is an important characteristic of grain shape and a key contributing factor to the grain yield in rice. Here, we report that gw2.1, a new allele of the Grain Width and Weight 2 (GW2) gene, regulates grain size and grain weight. A single nucleotide substitution in the coding sequence (CDS) of gw2.1 resulted in the change of glutamate to lysine (E128K) in GW2.1 protein. Complementation tests and GW2 overexpression experiments demonstrated that the missense mutation in gw2.1 was responsible for the phenotype of enlarged grain size in the mutant line jf42. The large grain trait of the near-isogenic line NIL-gw2.1 was found to result from increased cell proliferation during flower development. Meanwhile, NIL-gw2.1 was shown to increase grain yield without compromising the grain quality. The GW2 protein was localized to the cell nucleus and membrane, and interacted with CHB705, a subunit of the chromatin remodeling complex. Finally, the F1 hybrids from crosses of NIL-gw2.1 with 7 cytoplasmic male-sterile lines exhibited large grains and desirable grain appearance. Thus, gw2.1 is a promising allele that could be applied to improve grain yield and grain appearance in rice.
本文報(bào)道了粒寬和粒重基因GW2的新等位基因gw2.1，其可有效調(diào)控籽粒大小和粒重。值得注意的是，gw2.1不僅提高了水稻的籽粒產(chǎn)量，而且改善了水稻的籽粒品質(zhì)，這表明gw2.1有可能用于改善水稻的籽粒產(chǎn)量和品質(zhì)。