J Integr Plant Biol ›› 2024, Vol. 66 ›› Issue (7): 1440-1458.DOI: 10.1111/jipb.13674

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  • 收稿日期:2023-11-14 接受日期:2024-04-14 出版日期:2024-07-01 发布日期:2024-07-12

Natural variation in MORE GRAINS 1 regulates grain number and grain weight in rice

Yingchun Han1†, Qianfeng Hu2†, Nuo Gong1, Huimin Yan1, Najeeb Ullah Khan2, Yanxiu Du1, Hongzheng Sun1, Quanzhi Zhao1,3, Wanxi Peng4, Zichao Li2, Zhanying Zhang2* and Junzhou Li1*   

  1. 1. Henan Key Laboratory of Rice Molecular Breeding and High Efficiency Production, College of Agronomy, Henan Agricultural University, Zhengzhou 450046, China
    2. Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
    3. Rice Industrial Technology Research Institute, Guizhou University, Guiyang 550025, China
    4. School of Forestry, Henan Agricultural University, Zhengzhou 450046, China
    †These authors contributed equally to this work.
    *Correspondence: Zhanying Zhang (zhangzhanying@cau.edu.cn); Junzhou Li (lijunzhou199899@126.com, Dr. Li is fully responsible for the distributions of all materials associated with this article)
  • Received:2023-11-14 Accepted:2024-04-14 Online:2024-07-01 Published:2024-07-12

Abstract: Grain yield is determined mainly by grain number and grain weight. In this study, we identified and characterized MORE GRAINS1 (MOG1), a gene associated with grain number and grain weight in rice (Oryza sativa L.), through map-based cloning. Overexpression of MOG1 increased grain yield by 18.6%-22.3% under field conditions. We determined that MOG1, a bHLH transcription factor, interacts with OsbHLH107 and directly activates the expression of LONELY GUY(LOG), which encodes a cytokinin-activating enzyme and the cell expansion gene EXPANSIN-LIKE1(EXPLA1), positively regulating grain number per panicle and grain weight. Natural variations in the promoter and coding regions of MOG1 between Hap-LNW and Hap-HNW alleles resulted in changes in MOG1 expression level and transcriptional activation, leading to functional differences. Haplotype analysis revealed that Hap-HNW, which results in a greater number and heavier grains, has undergone strong selection but has been poorly utilized in modern lowland rice breeding. In summary, the MOG1-OsbHLH107 complex activates LOG and EXPLA1 expression to promote cell expansion and division of young panicles through the cytokinin pathway, thereby increasing grain number and grain weight. These findings suggest that Hap-HNW could be used in strategies to breed high-yielding temperate japonica lowland rice.

Key words: grain number,  grain weight, MOG1, natural variation, rice

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