College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China.
Plant Sci. 2022 Oct;323:111377. doi: 10.1016/j.plantsci.2022.111377. Epub 2022 Jul 9.
The thermo-sensitive cytoplasmic male-sterility line with Aegilops kotschyi cytoplasm (K-TCMS) is completely male sterile under low temperature (< 18 ℃) during Zadoks growth stages 45-52, whereas its fertility can be restored under hot temperature (≥ 20 ℃). The K-TCMS line may facilitate hybrid breeding and hybrid wheat production. Therefore, to elucidate the molecular mechanisms of its male sterility/fertility conversion, we conducted the association analysis of proteins and transcript expression to screen fertility related genes using RNA-seq, iTRAQ, and PRM-based assay. A gene encoding expansin protein in wheat, TaEXPB5, was isolated in K-TCMS line KTM3315A, which upregulated expression in the fertility anthers. Subcellular localization analysis suggested that TaEXPB5 protein localized to nucleus and cell wall. The silencing of TaEXPB5 displayed pollen abortion and the declination of fertility. Further, cytological investigation indicated that the silencing of TaEXPB5 induced the early degradation of tapetum and abnormal development of pollen wall. These results implied that TaEXPB5 may be essential for anther or pollen development and male fertility of KTM3315A. These findings provide a novel insight into molecular mechanism of fertility conversion for thermo-sensitive cytoplasmic male-sterility wheat, and contribute to the molecular breeding of hybrid wheat in the future.
携带有 Aegilops kotschyi 细胞质的温敏细胞质雄性不育系（K-TCMS）在小孢子发育时期的 Zadoks 45-52 阶段，低温（<18℃）下完全不育，而在高温（≥20℃）下可育。K-TCMS 系可促进杂种的选育和杂交小麦的生产。因此，为了阐明其不育/可育转换的分子机制，我们利用 RNA-seq、iTRAQ 和 PRM 技术进行了蛋白质和转录表达的关联分析，以筛选与育性相关的基因。在 K-TCMS 系 KTM3315A 中，我们分离到一个编码小麦扩展蛋白的基因 TaEXPB5，该基因在可育花药中表达上调。亚细胞定位分析表明，TaEXPB5 蛋白定位于细胞核和细胞壁。TaEXPB5 的沉默导致花粉败育和育性下降。进一步的细胞学研究表明，TaEXPB5 的沉默诱导了绒毡层的早期降解和花粉壁的异常发育。这些结果表明，TaEXPB5 可能对花药或花粉发育以及 KTM3315A 的雄性育性至关重要。这些发现为温敏细胞质雄性不育小麦育性转换的分子机制提供了新的见解，并为未来杂交小麦的分子育种做出了贡献。
