Background

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.

Results

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.

Conclusion

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.

中文翻译：

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OsMS188是水稻绒毡层发育和孢粉蛋白合成的关键调节剂

背景

在花药发育过程中，绒毡层为花粉发育提供了必要的营养和物质。在水稻中，已经从雄性不育系中克隆了绒毡层发育和花粉壁形成所必需的多种转录因子和酶。

结果

在这项研究中，我们获得了几条通过CRISPR-Cas9方法敲除MYB转录因子OsMS188的品系。所述osms188系显示与异常发展和绒毡层细胞的变性，不存在sexine层的和有缺陷的花药角质层雄性不育表型。CYP703A3，CYP704B2，OsPKS1，OsPKS2，DPW和ABCG15是水稻中孢粉蛋白合成和运输相关基因。这些基因中具有突变的植物是雄性不育的，具有缺陷的六丁香层和花药表皮。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有水稻绒毡层的发展上游调节。电泳迁移率迁移分析（EMSA）和激活分析表明，TDR直接调节OsMS188表达。另外，蛋白质相互作用测定表明TDR与OsMS188相互作用以调节下游基因表达。

结论

总体而言，OsMS188是绒毡层发育和花粉壁形成的关键调节剂。这项工作中建立的基因调控网络可能有助于将来对水稻和其他农作物的生育力调控进行研究。