2023-05-23 ペンシルベニア州立大学(PennState)
◆ペンシルベニア州立大学の研究チームが610種のランの遺伝子を比較し、ランの系統樹を再構築した結果、少なくとも14回の独立した進化が確認されました。この研究は、ランの保全や特性の進化の研究、新たな利用法の発見に役立つ可能性があります。
<関連情報>
- https://www.psu.edu/news/eberly-college-science/story/orchids-ability-grow-other-plants-independently-evolved-multiple-times/
- https://onlinelibrary.wiley.com/doi/10.1111/jipb.13462
核遺伝子を用いたラン科植物の包括的な系統解析と着生植物に関する進化的な知見を得る Comprehensive phylogenetic analyses of Orchidaceae using nuclear genes and evolutionary insights into epiphytism
Guojin Zhang, Yi Hu, Ming-Zhong Huang, Wei-Chang Huang, Ding-Kun Liu, Diyang Zhang, Haihua Hu, Jason L. Downing, Zhong-Jian Liu, Hong Ma
Journal of Integrative Plant Biology Published: 04 February 2023
DOI:https://doi.org/10.1111/jipb.13462
Abstract
Orchidaceae (with >28,000 orchid species) are one of the two largest plant families, with economically and ecologically important species, and occupy global and diverse niches with primary distribution in rainforests. Among orchids, 70% grow on other plants as epiphytes; epiphytes contribute up to ~50% of the plant diversity in rainforests and provide food and shelter for diverse animals and microbes, thereby contributing to the health of these ecosystems. Orchids account for over two-thirds of vascular epiphytes and provide an excellent model for studying evolution of epiphytism. Extensive phylogenetic studies of Orchidaceae and subgroups have ;been crucial for understanding relationships among many orchid lineages, although some uncertainties remain. For example, in the largest subfamily Epidendroideae with nearly all epiphytic orchids, relationships among some tribes and many subtribes are still controversial, hampering evolutionary analyses of epiphytism. Here we obtained 1,450 low-copy nuclear genes from 610 orchid species, including 431 with newly generated transcriptomes, and used them for the reconstruction of robust Orchidaceae phylogenetic trees with highly supported placements of tribes and subtribes. We also provide generally well-supported phylogenetic placements of 131 genera and 437 species that were not sampled by previous plastid and nuclear phylogenomic studies. Molecular clock analyses estimated the Orchidaceae origin at ~132 million years ago (Ma) and divergences of most subtribes from 52 to 29 Ma. Character reconstruction supports at least 14 parallel origins of epiphytism; one such origin was placed at the most recent common ancestor of ~95% of epiphytic orchids and linked to modern rainforests. Ten occurrences of rapid increase in the diversification rate were detected within Epidendroideae near and after the K-Pg boundary, contributing to ~80% of the Orchidaceae diversity. This study provides a robust and the largest family-wide Orchidaceae nuclear phylogenetic tree thus far and new insights into the evolution of epiphytism in vascular plants.
