Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200030, China.
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200030, China.
New Phytol. 2022 Mar;233(6):2629-2642. doi: 10.1111/nph.17939. Epub 2022 Jan 20.
Pollen protects male sperm and allows flowering plants to adapt to diverse terrestrial environments, thereby leading to the rapid expansion of plants into new regions. The process of anther/pollen development is coordinately regulated by internal and external factors including hormones. Currently, the molecular mechanisms underlying gibberellin (GA)-mediated male reproductive development in plants remain unknown. We show here that rice DELLA/SLR1, which encodes the central negative regulator of GA signaling, is essential for rice anther development. The slr1-5 mutant exhibits premature programmed cell death of the tapetum, lacks Ubisch bodies, and has no exine and no mature pollen. SLR1 is mainly expressed in tapetal cells and tetrads, and is required for the appropriate expression of genes encoding key factors of pollen development, which are suggested to be OsMS188-targeted genes. OsMS188 is the main component in the essential genetic program of tapetum and pollen development. Further, we demonstrate that SLR1 interacts with OsMS188 to cooperatively activate the expression of the sporopollenin biosynthesis and transport-related genes CYP703A3, DPW, ABCG15 and PKS1 for rapid formation of pollen walls. Overall, the results of this study suggest that the GA hormonal signal is integrated into the anther genetic program and regulates rice anther development through the GA-DELLA-OsMS188 module.
花粉保护雄性精子，使开花植物能够适应多样化的陆地环境，从而使植物迅速扩展到新的区域。花药/花粉发育的过程受到内部和外部因素（包括激素）的协调调节。目前，植物中赤霉素（GA）介导的雄性生殖发育的分子机制尚不清楚。我们在这里表明，编码 GA 信号中央负调节剂的水稻 DELLA/SLR1 对于水稻花药发育是必需的。slr1-5 突变体表现出绒毡层过早编程性细胞死亡，缺乏 Ubisch 小体，没有外壁和成熟花粉。SLR1 主要在绒毡层细胞和四分体中表达，并且对于编码花粉发育关键因子的基因的适当表达是必需的，这些基因被认为是 OsMS188 靶向基因。OsMS188 是绒毡层和花粉发育必需遗传程序的主要组成部分。此外，我们证明 SLR1 与 OsMS188 相互作用，共同激活与花粉壁快速形成有关的类脂素生物合成和运输相关基因 CYP703A3、DPW、ABCG15 和 PKS1 的表达。总的来说，这项研究的结果表明，GA 激素信号被整合到花药遗传程序中，并通过 GA-DELLA-OsMS188 模块调节水稻花药发育。
