Li Shuangcheng, Gao Fengyan, Xie Kailong, Zeng Xiuhong, Cao Ye, Zeng Jing, He Zhongshan, Ren Yun, Li Wenbo, Deng Qiming, Wang Shiquan, Zheng Aiping, Zhu Jun, Liu Huainian, Wang Lingxia, Li Ping
Rice Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan, China.
State Key Laboratory of Hybrid Rice, Sichuan Agricultural University, Chengdu, China.
Plant Biotechnol J. 2016 Nov;14(11):2134-2146. doi: 10.1111/pbi.12569. Epub 2016 May 17.
Grain weight is the most important component of rice yield and is mainly determined by grain size, which is generally controlled by quantitative trait loci (QTLs). Although numerous QTLs that regulate grain weight have been identified, the genetic network that controls grain size remains unclear. Herein, we report the cloning and functional analysis of a dominant QTL, grain length and width 2 (GLW2), which positively regulates grain weight by simultaneously increasing grain length and width. The GLW2 locus encodes OsGRF4 (growth-regulating factor 4) and is regulated by the microRNA miR396c in vivo. The mutation in OsGRF4 perturbs the OsmiR396 target regulation of OsGRF4, generating a larger grain size and enhanced grain yield. We also demonstrate that OsGIF1 (GRF-interacting factors 1) directly interacts with OsGRF4, and increasing its expression improves grain size. Our results suggest that the miR396c-OsGRF4-OsGIF1 regulatory module plays an important role in grain size determination and holds implications for rice yield improvement.
粒重是水稻产量的最重要组成部分，主要由粒型决定，而粒型通常受数量性状基因座（QTL）控制。尽管已经鉴定出许多调控粒重的QTL，但控制粒型的遗传网络仍不清楚。在此，我们报道了一个显性QTL——粒长宽2（GLW2）的克隆和功能分析，它通过同时增加粒长和粒宽来正向调控粒重。GLW2基因座编码OsGRF4（生长调控因子4），并在体内受microRNA miR396c调控。OsGRF4中的突变扰乱了OsmiR396对OsGRF4的靶向调控，产生更大的粒型并提高了籽粒产量。我们还证明OsGIF1（GRF相互作用因子1）直接与OsGRF4相互作用，增加其表达可改善粒型。我们的结果表明，miR396c-OsGRF4-OsGIF1调控模块在粒型决定中起重要作用，对提高水稻产量具有重要意义。
