The discovery of a wild abortive-type (WA) cytoplasmic male sterile (CMS) line and breeding its restorer line have led to the commercialization of three-line hybrid rice, contributing considerably to global food security. However, the molecular mechanisms underlying fertility abortion and the restoration of CMS-WA lines remain largely elusive. In this study, we cloned a restorer gene, , following a genome-wide association study analysis of the core parent lines of three-line hybrid rice. We found that was present in all core parental lines, but different haplotypes and structural variants of its gene resulted in differences in expression levels between sterile and restored lines. could restore pollen fertility in the CMS-WA line and was found to be responsible for fertility restoration in some CMS lines under high temperatures. In addition, we found that encodes a pentatricopeptide repeat protein that competes with WA352 for binding with COX11. This interaction enhances COX11’s function as a scavenger of reactive oxygen species, which in turn restores pollen fertility. Collectively, our study suggests a new action mode for pentatricopeptide repeat proteins in the fertility restoration of CMS lines, providing an essential theoretical basis for breeding robust restorer lines and for overcoming high temperature-induced fertility recovery of some CMS lines.

中文翻译：

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新的育性恢复基因Rf20的结构变异是水稻野生败育型细胞质雄性不育恢复的基础


野生败育型（WA）细胞质雄性不育（CMS）系的发现及其恢复系的育种导致了三系杂交水稻的商业化，为全球粮食安全做出了重大贡献。然而，生育力流产和 CMS-WA 系恢复的分子机制在很大程度上仍然难以捉摸。在这项研究中，我们对三系杂交水稻的核心亲本系进行了全基因组关联研究分析，克隆了一个恢复基因。我们发现它存在于所有核心亲本系中，但其基因的不同单倍型和结构变异导致不育系和恢复系之间表达水平的差异。可以恢复 CMS-WA 系中的花粉育性，并被发现有助于某些 CMS 系在高温下恢复育性。此外，我们发现编码五肽重复蛋白，该蛋白与 WA352 竞争与 COX11 的结合。这种相互作用增强了 COX11 作为活性氧清除剂的功能，从而恢复花粉育性。总的来说，我们的研究提出了五肽重复蛋白在CMS系育性恢复中的新作用模式，为选育健壮的恢复系和克服一些CMS系的高温诱导的育性恢复提供了重要的理论基础。