Self-incompatibility (SI), which has recurred during the evolution of plants, is one of the most important cross-pollination mating systems. Three S-loci have been reported in Brassicaceae, namely, Arabidopsis lyrata (Al), Brassica (Br), and Leavenworthia alabamica (La) S-loci. Here, through multi-genomic comparative analysis of 20 species, we revealed that the most ancient S-locus was formed prior to the divergence of Brassicaceae lineage I and II. It was retained and inherited by Arabidopsis, as the Al S-locus in Brassicaceae lineage I. Furthermore, we found that the Br S-locus, which has been widely used in the breeding of Brassica crops to generate hybrid seeds, was formed through segmental translocation (ST) in the hexaploid ancestor of Brassica in Brassicaceae lineage II. The Br S-locus was evolved through a ST from one of the triplicated ancestral S-locus paralogs in the Brassica hexaploidy ancestor, while the other two S-locus paralogs were lost. Together with the previous discovery that the La S-locus was formed through a secondary origin in Brassicaceae lineage I, we conclude the monophyletic origin of Al and Br S-loci and clarify the evolutionary route of S-loci in the Brassicaceae family. Our findings will contribute to evolutionary studies and breeding applications of the S-locus in Brassicaceae.

在植物进化过程中反复出现的自交不亲和性（SI）是最重要的异花授粉交配系统之一。三S-已报道十字花科位点，即，琴叶拟南芥（铝），油菜（溴），和Leavenworthia alabamica（香格里拉）S-位点。在这里，通过对20个物种的多基因组比较分析，我们发现最古老的S-基因座是在十字花科第一代和第二代分化之前形成的。它被拟南芥保留并继承为Al S-locus在十字花科谱系I.此外，我们发现，宽单峰-locus，其已被广泛用于在育种芸苔属作物，以产生杂交种子，通过在的六倍体祖先节段性易位（ST）形成芸苔属中十字花科血统II。的宽单峰-locus物通过ST从之一放出的三重祖S-轨迹旁系同源物在芸苔属六倍体祖先，而其他两个S-轨迹旁系同源物丢失。连同先前的发现，La S-基因座是通过十字花科第一类的次生起源形成的，我们得出了Al的单系起源。和Br S -loci，并阐明了十字花科家族中S-基因的进化途径。我们的发现将有助于十字花科植物S-基因座的进化研究和育种应用。