Han Yu, Zhou Si-Da, Fan Jiong-Jiong, Zhou Lei, Shi Qiang-Sheng, Zhang Yan-Fei, Liu Xing-Lu, Chen Xing, Zhu Jun, Yang Zhong-Nan
Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, 200234, China.
Rice (N Y). 2021 Jan 6;14(1):4. doi: 10.1186/s12284-020-00451-y.
During anther development, the tapetum provides essential nutrients and materials for pollen development. In rice, multiple transcription factors and enzymes essential for tapetum development and pollen wall formation have been cloned from male-sterile lines.
In this study, we obtained several lines in which the MYB transcription factor OsMS188 was knocked out through the CRISPR-Cas9 approach. The osms188 lines exhibited a male-sterile phenotype with aberrant development and degeneration of tapetal cells, absence of the sexine layer and defective anther cuticles. CYP703A3, CYP704B2, OsPKS1, OsPKS2, DPW and ABCG15 are sporopollenin synthesis and transport-related genes in rice. Plants with mutations in these genes are male sterile, with a defective sexine layer and anther cuticle. Further biochemical assays demonstrated that OsMS188 binds directly to the promoters of these genes to regulate their expression. UDT1, OsTDF1, TDR, bHLH142 and EAT1 are upstream regulators of rice tapetum development. Electrophoretic mobility shift assays (EMSAs) and activation assays revealed that TDR directly regulates OsMS188 expression. Additionally, protein interaction assays indicated that TDR interacts with OsMS188 to regulate downstream gene expression.
Overall, OsMS188 is a key regulator of tapetum development and pollen wall formation. The gene regulatory network established in this work may facilitate future investigations of fertility regulation in rice and in other crop species.
在花药发育过程中，绒毡层为花粉发育提供必需的营养物质和材料。在水稻中，已从雄性不育系中克隆出多个对绒毡层发育和花粉壁形成至关重要的转录因子和酶。
在本研究中，我们通过CRISPR-Cas9方法获得了几个敲除MYB转录因子OsMS188的株系。osms188株系表现出雄性不育表型，绒毡层细胞发育异常并退化，缺乏外壁外层，花药角质层有缺陷。CYP703A3、CYP704B2、OsPKS1、OsPKS2、DPW和ABCG15是水稻中与孢粉素合成和运输相关的基因。这些基因发生突变的植株雄性不育，外壁外层和花药角质层有缺陷。进一步的生化分析表明，OsMS188直接与这些基因的启动子结合以调节其表达。UDT1、OsTDF1、TDR、bHLH142和EAT1是水稻绒毡层发育的上游调节因子。电泳迁移率变动分析（EMSA）和激活分析表明，TDR直接调节OsMS188的表达。此外，蛋白质相互作用分析表明，TDR与OsMS188相互作用以调节下游基因表达。
总体而言，OsMS188是绒毡层发育和花粉壁形成的关键调节因子。本研究建立的基因调控网络可能有助于未来对水稻和其他作物育性调控的研究。
