Zhang Lisha, Zheng Lintao, Wu Jingwen, Liu Yang, Liu Weichi, He Guanghua, Wang Nan
Key Laboratory of Application and Safety Control of Genetically Modified Crops, College of Agronomy and Biotechnology, Rice Research Institute, Southwest University, Chongqing, 400715, China.
Rice (N Y). 2023 Feb 27;16(1):10. doi: 10.1186/s12284-023-00628-1.
Phenylpropanoid metabolism and timely tapetal degradation are essential for anther and pollen development, but the underlying mechanisms are unclear. In the current study, to investigate this, we identified and analyzed the male-sterile mutant, osccrl1 (cinnamoyl coA reductase-like 1), which exhibited delayed tapetal programmed cell death (PCD) and defective mature pollen. Map-based cloning, genetic complementation, and gene knockout revealed that OsCCRL1 corresponds to the gene LOC_Os09g32020.2, a member of SDR (short-chain dehydrogenase/reductase) family enzyme. OsCCRL1 was preferentially expressed in the tapetal cells and microspores, and localized to the nucleus and cytoplasm in both rice protoplasts and Nicotiana benthamiana leaves. The osccrl1 mutant exhibited reduced CCRs enzyme activity, less lignin accumulation, delayed tapetum degradation, and disrupted phenylpropanoid metabolism. Furthermore, an R2R3 MYB transcription factor OsMYB103/OsMYB80/OsMS188/BM1, involved in tapetum and pollen development, regulates the expression of OsCCRL1. Finally, the osmyb103 osccrl1 double mutants, exhibited the same phenotype as the osmyb103 single mutant, further indicating that OsMYB103/OsMYB80/OsMS188/BM1 functions upstream of OsCCRL1. These findings help to clarify the role of phenylpropanoid metabolism in male sterility and the regulatory network underlying the tapetum degradation.
苯丙烷类代谢和绒毡层的适时降解对花药和花粉发育至关重要，但其潜在机制尚不清楚。在本研究中，为了探究这一点，我们鉴定并分析了雄性不育突变体osccrl1（肉桂酰辅酶A还原酶样1），该突变体表现出绒毡层程序性细胞死亡（PCD）延迟和成熟花粉缺陷。基于图谱的克隆、遗传互补和基因敲除表明，OsCCRL1对应于基因LOC_Os09g32020.2，是短链脱氢酶/还原酶（SDR）家族酶的成员。OsCCRL1在绒毡层细胞和小孢子中优先表达，并定位于水稻原生质体和本氏烟草叶片的细胞核和细胞质中。osccrl1突变体表现出CCRs酶活性降低、木质素积累减少、绒毡层降解延迟以及苯丙烷类代谢紊乱。此外，参与绒毡层和花粉发育的R2R3 MYB转录因子OsMYB103/OsMYB80/OsMS188/BM1调节OsCCRL1的表达。最后，osmyb103 osccrl1双突变体表现出与osmyb103单突变体相同的表型，进一步表明OsMYB103/OsMYB80/OsMS188/BM1在OsCCRL1的上游发挥作用。这些发现有助于阐明苯丙烷类代谢在雄性不育中的作用以及绒毡层降解的调控网络。
