State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China.
Department of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762, United States of America.
Nat Commun. 2021 Nov 26;12(1):6930. doi: 10.1038/s41467-021-26922-4.
Chloranthales remain the last major mesangiosperm lineage without a nuclear genome assembly. We therefore assemble a high-quality chromosome-level genome of Chloranthus spicatus to resolve enigmatic evolutionary relationships, as well as explore patterns of genome evolution among the major lineages of mesangiosperms (eudicots, monocots, magnoliids, Chloranthales, and Ceratophyllales). We find that synteny is highly conserved between genomic regions of Amborella, Vitis, and Chloranthus. We identify an ancient single whole-genome duplication (WGD) (κ) prior to the divergence of extant Chloranthales. Phylogenetic inference shows Chloranthales as sister to magnoliids. Furthermore, our analyses indicate that ancient hybridization may account for the incongruent phylogenetic placement of Chloranthales + magnoliids relative to monocots and eudicots in nuclear and chloroplast trees. Long genes and long introns are found to be prevalent in both Chloranthales and magnoliids compared to other angiosperms. Overall, our findings provide an improved context for understanding mesangiosperm relationships and evolution and contribute a valuable genomic resource for future investigations.
金粟兰目仍然是最后一个没有核基因组组装的主要中柱植物谱系。因此，我们组装了金粟兰属植物的高质量染色体水平基因组，以解决神秘的进化关系，并探索中柱植物（真双子叶植物、单子叶植物、木兰类植物、金粟兰目和金鱼藻目）主要谱系之间的基因组进化模式。我们发现，Amborella、葡萄属和金粟兰属的基因组区域之间的同线性高度保守。我们确定在现存金粟兰目分化之前存在一个古老的全基因组重复（WGD）（κ）。系统发育推断表明金粟兰目与木兰类植物是姐妹群。此外，我们的分析表明，古老的杂交可能导致金粟兰目+木兰类植物在核和叶绿体树中相对于单子叶植物和真双子叶植物的系统发育位置不一致。与其他被子植物相比，长基因和长内含子在金粟兰目和木兰类植物中都很常见。总的来说，我们的研究结果为理解中柱植物的关系和进化提供了一个改进的背景，并为未来的研究提供了有价值的基因组资源。
