Origin, loss, and regain of self-incompatibility in angiosperms

作者：Hong Zhao, Yue Zhang, Hui Zhang, Yanzhai Song, Fei Zhao, Yue Zhang, Sihui Zhu, Hongkui Zhang, Zhendiao Zhou, Han Guo, Miaomiao Li, Junhui Li, Qiang Gao, Qianqian Han, Huaqiu Huang, Lucy Copsey, Qun Li, Hua Chen, Enrico Coen, Yijing Zhang, Yongbiao Xue · 发表于：The Plant Cell · 年份：2021 · DOI：10.1093/plcell/koab266 · 被引用次数：87 · 研究领域：Plant Reproductive Biology、Plant Molecular Biology Research、Plant and animal studies

The self-incompatibility (SI) system with the broadest taxonomic distribution in angiosperms is based on multiple S-locus F-box genes (SLFs) tightly linked to an S-RNase termed type-1. Multiple SLFs collaborate to detoxify nonself S-RNases while being unable to detoxify self S-RNases. However, it is unclear how such a system evolved, because in an ancestral system with a single SLF, many nonself S-RNases would not be detoxified, giving low cross-fertilization rates. In addition, how the system has been maintained in the face of whole-genome duplications (WGDs) or lost in other lineages remains unclear. Here we show that SLFs from a broad range of species can detoxify S-RNases from Petunia with a high detoxification probability, suggestive of an ancestral feature enabling cross-fertilization and subsequently modified as additional SLFs evolved. We further show, based on its genomic signatures, that type-1 was likely maintained in many lineages, despite WGD, through deletion of duplicate S-loci. In other lineages, SI was lost either through S-locus deletions or by retaining duplications. Two deletion lineages regained SI through type-2 (Brassicaceae) or type-4 (Primulaceae), and one duplication lineage through type-3 (Papaveraceae) mechanisms. Thus, our results reveal a highly dynamic process behind the origin, maintenance, loss, and regain of SI.