Wang Shuaibin, Gao Junping, Li Zhaowu, Chen Kai, Pu Wenxuan, Feng Chen
Tobacco Research Institute of Technology Centre, China Tobacco Hunan Industrial Corporation, Changsha, China.
Puai Medical College, Shaoyang University, Shaoyang, China.
Front Plant Sci. 2023 Jul 28;14:1205683. doi: 10.3389/fpls.2023.1205683. eCollection 2023.
L. (Solanaceae) is of great scientific and economic importance, and polyploidization has been pivotal in shaping this genus. Despite many previous studies on the phylogenetic relationship and hybridization, evidence from whole genome data is still lacking.
In this study, we obtained 995 low-copy genes and plastid transcript fragments from the transcriptome datasets of 26 species, including all sections. We reconstructed the phylogenetic relationship and phylogenetic network of diploid species.
The incongruence among gene trees showed that the formation of involved incomplete lineage sorting. The nuclear-plastid discordance and nuclear introgression absence indicated that organelle capture from section was involved in forming section . Furthermore, we analyzed the evolutionary origin of polyploid species and dated the time of hybridization events based on the analysis of PhyloNet, sequence similarity search, and phylogeny of subgenome approaches. Our results highly evidenced the hybrid origins of five polyploid sections, including sections , and . Notably, we provide novel insights into the hybridization event of section and . The section formed from a single hybridization event between maternal progenitor and paternal progenitor ; the (paternal progenitor) and the (maternal progenitor) were involved in the formation of section .
This study represents the first exploration of polyploidization events and phylogenetic relationships using the high-throughput RNA-seq approach. It will provide guidance for further studies in molecular systematics, population genetics, and ecological adaption studies in and other related species.
茄属在科学和经济方面具有重大意义，多倍体化在塑造该属的过程中起着关键作用。尽管此前有许多关于系统发育关系和杂交的研究，但仍缺乏来自全基因组数据的证据。
在本研究中，我们从26个物种的转录组数据集中获得了995个低拷贝基因和质体转录片段，这些物种涵盖了所有组。我们重建了二倍体物种的系统发育关系和系统发育网络。
基因树之间的不一致表明茄属的形成涉及不完全谱系分选。核质不一致以及不存在核基因渐渗表明从某一组捕获细胞器参与了另一组的形成。此外，我们基于PhyloNet分析、序列相似性搜索和亚基因组系统发育分析了多倍体物种的进化起源，并确定了杂交事件的时间。我们的结果有力地证明了五个多倍体组的杂交起源，包括某几个组。值得注意的是，我们对某一组和另一组的杂交事件提供了新的见解。某一组由母本祖先和父本祖先之间的一次杂交事件形成；某一父本祖先和某一母本祖先参与了另一组的形成。
本研究是首次使用高通量RNA测序方法探索茄属多倍体化事件和系统发育关系。它将为茄属及其他相关物种的分子系统学、群体遗传学和生态适应性研究的进一步开展提供指导。
