Li Zhu-Hao, Wang Shi-Lin, Zhu Yu-Jun, Fan Ye-Yang, Huang De-Run, Zhu Ai-Ke, Zhuang Jie-Yun, Liang Yan, Zhang Zhen-Hua
State Key Laboratory of Rice Biology and Chinese National Center for Rice Improvement, China National Rice Research Institute, Hangzhou 310006, China.
Nanchong Academy of Agricultural Sciences, Nanchong 637000, China.
Plants (Basel). 2022 Sep 27;11(19):2530. doi: 10.3390/plants11192530.
Grain shape and size are key determinants of grain appearance quality and yield in rice. In our previous study, a grain shape QTL, , was fine-mapped using near-isogenic lines (NILs) derived from a cross between Zhenshan 97 (ZS97) and Milyang 46 (MY46). One annotated gene, , was found to be the most likely candidate gene. Here, knockout and overexpression experiments were performed to investigate the effects of on grain shape and size. Four traits were tested, including grain length, grain width, grain weight, and the ratio of grain length to width. Knockout of in NIL, NIL, and another rice cultivar carrying the allele all caused decreases in grain width and weight and increases in the ratio of grain length to width. Results also showed that the magnitude of the mutational effects varied depending on the target allele and the genetic background. Moreover, it was found that NIL and NIL carried different functional alleles of , causing differences in grain shape rather than grain weight. In the overexpression experiment, significant differences between transgenic-positive and transgenic-negative plants were detected in all four traits. These results indicate that regulates grain shape and size through a complex mechanism and is a good target for deciphering the regulatory network of grain shape. This gene could be used to improve grain appearance quality through molecular breeding as well.
粒形和粒大小是水稻粒外观品质和产量的关键决定因素。在我们之前的研究中，利用珍汕97（ZS97）和密阳46（MY46）杂交衍生的近等基因系（NILs）对一个粒形QTL进行了精细定位。发现一个注释基因是最有可能的候选基因。在此，进行了敲除和过表达实验以研究该基因对粒形和粒大小的影响。测试了四个性状，包括粒长、粒宽、粒重和粒长与粒宽之比。在NIL、NIL以及另一个携带该等位基因的水稻品种中敲除该基因均导致粒宽和粒重降低，粒长与粒宽之比增加。结果还表明，突变效应的大小因目标等位基因和遗传背景而异。此外，发现NIL和NIL携带该基因的不同功能等位基因，导致粒形而非粒重存在差异。在过表达实验中，在所有四个性状上均检测到转基因阳性和转基因阴性植株之间存在显著差异。这些结果表明，该基因通过复杂机制调控粒形和粒大小，是解析粒形调控网络的良好靶点。该基因也可用于通过分子育种改善粒外观品质。
