Wu Wenhao, Li Hongyu, Zhou Qian, Wu Bowen, Huang Weiting, Fang Zhongming
Institute of Rice Industry Technology Research, Key Laboratory of Functional Agriculture of Guizhou Provincial Higher Education Institutions, Key Laboratory of Molecular Breeding for Grain and Oil Crops in Guizhou Province, College of Agricultural Sciences, Guizhou University, Guiyang, Guizhou, 550025, China.
Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang, Guizhou, 550025, China.
Plant J. 2025 Mar;121(6):e70107. doi: 10.1111/tpj.70107.
Rice tillering determines grain yield, yet the molecular regulatory network is still limited. In this study, we demonstrated that the transcription factor OsMADS60 promotes the expression of the auxin transporter OsPIN5b to affect auxin distribution and inhibit rice tillering and grain yield. Natural variation was observed in the promoter region of OsMADS60, with its expression level negatively correlated with tiller number and inducible by auxin. Overexpression of OsMADS60 resulted in reduced tillers and grain yield, whereas CRISPR-mediated knockouts of OsMADS60 led to increased tillering and yield. OsMADS60 was found to directly bind the CArG motif [CATTTAC] in the OsPIN5b promoter, thereby upregulating its expression. Moreover, we found that auxin content in various tissues of OsMADS60 and OsPIN5b overexpression lines increased relative to the wild-type ZH11, whereas the auxin levels in mutant lines showed the opposite trend. Genetic analysis further confirmed that OsPIN5b acted downstream of OsMADS60, coregulating the expression of genes involved in hormone pathways. Our findings reveal that OsMADS60 modulates auxin distribution by promoting OsPIN5b expression, thereby influencing rice tillering. This regulatory mechanism holds significant potential for the genetic improvement of rice architecture and grain yield.
水稻分蘖决定着产量，但其分子调控网络仍较为有限。在本研究中，我们证明转录因子OsMADS60促进生长素转运蛋白OsPIN5b的表达，从而影响生长素分布并抑制水稻分蘖和产量。在OsMADS60的启动子区域观察到自然变异，其表达水平与分蘖数呈负相关且受生长素诱导。过表达OsMADS60导致分蘖数和产量降低，而CRISPR介导的OsMADS60敲除则导致分蘖增加和产量提高。发现OsMADS60直接结合OsPIN5b启动子中的CArG基序[CATTTAC]，从而上调其表达。此外，我们发现，相对于野生型ZH11，OsMADS60和OsPIN5b过表达系各组织中的生长素含量增加，而突变体系中的生长素水平则呈现相反趋势。遗传分析进一步证实OsPIN5b在OsMADS60下游起作用，共同调控参与激素途径的基因表达。我们的研究结果表明，OsMADS60通过促进OsPIN5b表达来调节生长素分布，从而影响水稻分蘖。这种调控机制在水稻株型和产量的遗传改良方面具有巨大潜力。
