Yang Yuqi, Zhang Zhining, Liu Jun, Tang Luyao, Wei Yiting, Nong Wen, Yin Lu, Li Sanfeng, Duan Penggen, Wang Yuexing, Rao Yuchun
College of Life Sciences, Zhejiang Normal University, Jinhua 321004, Zhejiang, China.
China National Center for Rice Improvement/State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, Zhejiang, China.
Sheng Wu Gong Cheng Xue Bao. 2025 Jul 25;41(7):2789-2802. doi: 10.13345/j.cjb.250179.
Rice is the world's largest food crop, and its yield and quality are directly related to food security and human health. Grain size, as one of the important factors determining the rice yield, has been widely concerned by breeders and researchers for a long time. To decipher the regulatory mechanism of rice grain size, we obtained a multi-tiller, dwarf, and small-grain mutant by ethyl methanesulfonate (EMS) mutation from the rice cultivar 'Zhonghua 11' ('ZH11'). Genetic analysis indicated that the phenotype of was controlled by a single recessive gene. Using the mutation site map (Mutmap) method, we identified the candidate gene , which encoded a carotenoid cleavage dioxygenase involved in the biosynthesis of strigolactone (SL). The SL content in was significantly lower than that in 'ZH11'. Cytological analysis showed that the grain size of the mutant decreased due to the reductions in the length and width of glume cells. The function of was further verified by the CRISPR/cas9 gene editing technology. The plants with the gene knockout exhibited similar grain size to the mutant. In addition, gene expression analysis showed that the expression levels of multiple grain size-related genes in the mutant changed significantly, suggesting that may interact with other genes regulating grain size. This study provides a new theoretical basis for research on the regulatory mechanism of rice grain size and potential genetic resources for breeding the rice cultivars with high yields.
水稻是世界上种植面积最大的粮食作物，其产量和品质直接关系到粮食安全和人类健康。粒型作为决定水稻产量的重要因素之一，长期以来一直受到育种者和研究者的广泛关注。为了解析水稻粒型的调控机制，我们通过甲基磺酸乙酯（EMS）诱变处理水稻品种‘中花11’（‘ZH11’）获得了一个多分蘖、矮化且小粒的突变体。遗传分析表明，该突变体的表型受一个单隐性基因控制。利用突变位点图谱（Mutmap）方法，我们鉴定出候选基因，该基因编码一种参与独脚金内酯（SL）生物合成的类胡萝卜素裂解双加氧酶。该突变体中的SL含量显著低于‘中花11’。细胞学分析表明，突变体的粒型变小是由于颖壳细胞长度和宽度的减小。通过CRISPR/cas9基因编辑技术进一步验证了该基因的功能。基因敲除的植株表现出与突变体相似的粒型。此外，基因表达分析表明，突变体中多个与粒型相关基因的表达水平发生了显著变化，这表明该基因可能与其他调控粒型的基因相互作用。本研究为水稻粒型调控机制的研究提供了新的理论依据，并为培育高产水稻品种提供了潜在的遗传资源。
