Hu Li, Yang Rui, Wang Yue-Hua, Gong Xun
Plant Science Institute, School of Life Sciences, Yunnan University, Kunming 650201, Yunnan, China.
CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
AoB Plants. 2021 Mar 4;13(2):plab012. doi: 10.1093/aobpla/plab012. eCollection 2021 Apr.
Natural hybridization is frequent in plants and is considered an important factor facilitating speciation. The natural intergeneric hybridization between and was previously confirmed using a couple of DNA markers. However, the mechanism of this intergeneric hybridization and the role of reproductive isolation in the process of hybridization remain unclear. Here we used double-digest restriction site-associated DNA sequencing (ddRAD-seq) to further quantify the occurrence of hybridization, the genetic structure of the hybrid population and the role of reproductive isolation between and . The results based on the ddRAD-seq SNP data sets indicated that hybridization between and was restricted to Fs, and no gene introgression was identified between these two species. STRUCTURE analysis and maximum likelihood (ML) tree results showed a slightly larger genetic contribution of to putative hybrid Fs. We deduced that the reproductive isolation between these two parent species is not well-developed but still strong enough to maintain the genetic integrity of the species, and that their Fs are sterile or with low fertility. Given the poorly resolved phylogenetic relationship between and , the occurrence of natural hybridization between and may provide new insights into the re-circumscription and re-delimitation of these two genera.
自然杂交在植物中很常见，被认为是促进物种形成的一个重要因素。先前已使用一些DNA标记证实了[两个属名未给出]之间的自然属间杂交。然而，这种属间杂交的机制以及生殖隔离在杂交过程中的作用仍不清楚。在这里，我们使用双酶切限制性位点关联DNA测序（ddRAD-seq）来进一步量化杂交的发生率、杂交群体的遗传结构以及[两个属名未给出]之间生殖隔离的作用。基于ddRAD-seq SNP数据集的结果表明，[两个属名未给出]之间的杂交仅限于Fs，并且在这两个物种之间未发现基因渗入。STRUCTURE分析和最大似然（ML）树结果显示，[一个属名未给出]对假定的杂交种Fs的遗传贡献略大。我们推断，这两个亲本物种之间的生殖隔离虽未充分发展，但仍足以维持物种的遗传完整性，并且它们的Fs是不育的或育性较低。鉴于[两个属名未给出]之间的系统发育关系尚未明确解决，[两个属名未给出]之间自然杂交的发生可能为这两个属的重新界定和重新划分提供新的见解。
