Chen Jia-Dan, Lin Tao, Wang Wan, Jin Cheng, Zuo Jian-Ru, Nian Jin-Qiang
College of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China.
College of Horticulture, China Agricultural University, Beijing 100193, China.
Yi Chuan. 2025 Jul 20;47(7):797-812. doi: 10.16288/j.yczz.25-084.
The number of tillers, the number of grains per panicle and the weight of grains, which are interrelated, mutually restricted and mutually compensated. In addition, they mainly determine the grain yield per plant in rice; especially panicle number and grain number per panicle have a large negative correlation, so high yield can be obtained only in the case of coordinated development of all factors. Nevertheless, many of the modes that regulate rice grain number and grain size remain unexplained and require further study, owing to the complex regulatory modes within and among the pathways. In this study, two mutants of grain number have been identified in the background of KY131 (Kongyu131, an excellent rice variety in Northeast of China) by EMS mutagens, named as () and . Compared with the wild type, the and mutants have excellent agronomic traits, including the plant height, yield per plant, panicle length, number of grains per spike, grain length, grain width and grain thickness, while significantly decreased the number of tillers. Genetic analysis showed that and were allelic mutants or the same mutant, and the mutation in a recessive nuclear gene caused their phenotypes. The results of MutMap analysis based on resequencing and map cloning showed that the was located in the 576 kb physical interval between M33 and M28 markers on chromosome 1 in rice. Cytological analysis of young panicle and glume epidermis in mutants indicated that mutant have higher cell division frequency and cell size during differentiation of young panicle. In addition, the mutants have significantly higher the expression levels of cyclin-related genes , , and than wild type, suggesting that may be involved in panicle development and yield formation by regulating cell division in rice. In summary, gene plays an important role in the regulation of the differentiation and development of panicle, which will provide a new idea for molecular design breeding to improve high and stable yield in rice.
分蘖数、每穗粒数和粒重相互关联、相互制约且相互补偿。此外，它们主要决定水稻单株产量；尤其是穗数和每穗粒数呈较大的负相关，因此只有在所有因素协调发展的情况下才能获得高产。然而，由于途径内部和之间复杂的调控模式，许多调节水稻粒数和粒大小的模式仍未得到解释，需要进一步研究。在本研究中，通过甲基磺酸乙酯（EMS）诱变剂在KY131（空育131，中国东北优良水稻品种）背景下鉴定出两个粒数突变体，命名为（）和。与野生型相比，和突变体具有优良的农艺性状，包括株高、单株产量、穗长、每穗粒数、粒长、粒宽和粒厚，而分蘖数显著减少。遗传分析表明，和是等位突变体或同一突变体，隐性核基因的突变导致了它们的表型。基于重测序和图位克隆的MutMap分析结果表明，位于水稻第1染色体上M33和M28标记之间576 kb的物理区间内。对突变体幼穗和颖壳表皮的细胞学分析表明，突变体在幼穗分化过程中具有较高的细胞分裂频率和细胞大小。此外，突变体中细胞周期蛋白相关基因、、和的表达水平显著高于野生型，表明可能通过调节水稻细胞分裂参与穗发育和产量形成。综上所述，基因在穗分化和发育调控中起重要作用，这将为分子设计育种提高水稻高产稳产提供新思路。
