Li Yan, Guo Xuelian, Song Jiayi, Xu Kun, Qin Tian, Zhang Xianhua, Song Zhaojian, He Yuchi, Zhang Biaoming, Zhang Haitao, Li Haitao, Yuan Wenya
State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.
State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.
Plant Commun. 2025 Jun 9;6(6):101348. doi: 10.1016/j.xplc.2025.101348. Epub 2025 May 2.
The identification of seed development-related regulators is critical for the genetic improvement of yield and grain quality in cereal crops. SQUAMOSA PROMOTER BINDING PROTEIN-LIKE14 (OsSPL14) is a well-studied, plant-specific transcription factor; however, its roles in controlling rice grain appearance quality and the underlying molecular mechanisms have not been fully elucidated. In this study, we demonstrate that OsSPL14 positively regulates appearance quality by controlling grain chalkiness in rice. Genetic analysis revealed that knockdown or knockout of OsSPL14 leads to a chalky grain phenotype, which is associated with significant defects in compound starch granules and notable changes in both starch and protein contents in the endosperm. Transcript analysis identified multiple genes regulated by OsSPL14, including the key granule-bound starch synthase gene Waxy (Wx) and the protein disulfide isomerase-like enzyme-encoding gene PDIL1-1. Both in vitro and in vivo assays demonstrated that OsSPL14 directly binds to the GTAC-box motif in the Wx and PDIL1-1 promoters to enhance their expression. Protein-protein interaction experiments further revealed that OsSPL14 interacts with the nuclear transcription factor Y (NF-Y) heterodimer OsNF-YB9/YC8-12 to promote the transcription of Wx and PDIL1-1, thereby enhancing rice grain appearance quality. Our findings uncover a novel regulatory pathway controlled by OsSPL14 and provide new insights into the molecular mechanisms underlying rice grain appearance quality, with promising implications for genetic improvement in rice.
鉴定与种子发育相关的调控因子对于谷类作物产量和籽粒品质的遗传改良至关重要。SQUAMOSA启动子结合蛋白样14（OsSPL14）是一种经过充分研究的植物特异性转录因子；然而，其在控制水稻籽粒外观品质方面的作用及潜在分子机制尚未完全阐明。在本研究中，我们证明OsSPL14通过控制水稻籽粒垩白度来正向调控外观品质。遗传分析表明，敲低或敲除OsSPL14会导致籽粒垩白表型，这与复合淀粉粒的显著缺陷以及胚乳中淀粉和蛋白质含量的明显变化有关。转录分析鉴定出多个受OsSPL14调控的基因，包括关键的颗粒结合淀粉合酶基因蜡质（Wx）和编码蛋白二硫键异构酶样酶的基因PDIL1-1。体外和体内试验均表明，OsSPL14直接结合Wx和PDIL1-1启动子中的GTAC-box基序以增强其表达。蛋白质-蛋白质相互作用实验进一步揭示，OsSPL14与核转录因子Y（NF-Y）异二聚体OsNF-YB9/YC8-12相互作用，以促进Wx和PDIL1-1的转录，从而提高水稻籽粒外观品质。我们的研究结果揭示了一条由OsSPL14控制的新调控途径，并为水稻籽粒外观品质的潜在分子机制提供了新见解，对水稻的遗传改良具有重要意义。
