Pollen development is critical to the reproductive success of flowering plants, but how it is regulated is not well understood. Here, we isolated two allelic male-sterile mutants of OsMYB80 and investigated how OsMYB80 regulates male fertility in rice. OsMYB80 was barely expressed in tissues other than anthers, where it initiated the expression during meiosis, reached the peak at the tetrad-releasing stage and then quickly declined afterward. The osmyb80 mutants exhibited premature tapetum cell death, lack of Ubisch bodies, no exine and microspore degeneration. To understand how OsMYB80 regulates anther development, RNA-seq analysis was conducted to identify genes differentially regulated by OsMYB80 in rice anthers. In addition, DNA affinity purification sequencing (DAP-seq) analysis was performed to identify DNA fragments interacting with OsMYB80 in vitro. Overlap of the genes identified by RNA-seq and DAP-seq revealed 188 genes that were differentially regulated by OsMYB80 and also carried an OsMYB80-interacting DNA element in the promoter. Ten of these promoter elements were randomly selected for gel shift assay and yeast one-hybrid assay, and all showed OsMYB80 binding. The 10 promoters also showed OsMYB80-dependent induction when co-expressed in rice protoplast. Functional annotation of the 188 genes suggested that OsMYB80 regulates male fertility by directly targeting multiple biological processes. The identification of these genes significantly enriched the gene networks governing anther development and provided much new information for the understanding of pollen development and male fertility.

中文翻译：

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OsMYB80通过靶向多种生物途径来调节花药发育和花粉育性。

花粉发育对于开花植物的生殖成功至关重要，但是如何对其进行调节尚不十分清楚。在这里，我们分离了两个OsMYB80等位基因雄性不育突变体，并研究了OsMYB80如何调节水稻的雄性育性。OsMYB80在花药以外的组织中几乎不表达，在减数分裂期间它开始表达，在四分体释放阶段达到峰值，然后迅速下降。osmyb80突变体表现出过早的绒毡层细胞死亡，缺乏Ubisch体，没有外在和小孢子变性。为了了解OsMYB80如何调节花药发育，进行了RNA序列分析以鉴定水稻花药中受OsMYB80差异调节的基因。此外，进行了DNA亲和纯化测序（DAP-seq）分析，以鉴定与OsMYB80体外相互作用的DNA片段。RNA-seq和DAP-seq鉴定的基因重叠显示188个受OsMYB80差异调节的基因，并且在启动子中还携带与OsMYB80相互作用的DNA元件。这些启动子元件中的十个被随机选择用于凝胶迁移测定和酵母一杂交测定，并且全部显示出OsMYB80结合。当在水稻原生质体中共表达时，这10个启动子也显示出OsMYB80依赖性诱导。188个基因的功能注释表明，OsMYB80通过直接靶向多种生物学过程来调节雄性育性。