PJB-2018-1018
Phylogeny of Rheum (Polygonaceae) based on cpDNA trnS-G sequences
Weiwei Li and Ailan Wang
Abstract
Rheum L. is a perennial herb of Polygonaceae, with about 60 species, most of which are distributed in the Qinghai-Tibet Plateau (QTP). Due to the unique habitats of the QTP, Rheum L. was one of the typical representatives for studying the species diversity of this region. To investigate the monophyletic origin of this genus and evaluate its infrageneric relationships, a total of 27 individuals distributed in seven of eight sections of Rheum (only excluding Sect. Orbicularia) were collected in the QTP and adjacent areas. Molecular phylogenetic trees were reconstructed based on cpDNA trnS-G sequences. The results showed that the monophyletic origin of Sect. Palmata was supported, while another six sections (Sect. Rheum, Sect. Acuminata, Sect. Deserticola, Sect. Spiciformia, Sect. Globulosa and Sect. Nobilia) were found to be paraphyletic origin. Rh. kialense of Sect. Acuminata clustered as a subclade with Rh. Likiangense 3 of Sect. Rheum, Rh. pumilum and Rh. sublanceolatum of Sect. Deserticola. Rh. alexandrae and Rh.nobile, the only two species in Sect. Nobilia, also scattered in different groups. The monophyletic origin of the monotypic Sect. (Globulosum) was also unsupported, and it was found to be clustered together with Rh. nanum of Sect. Deserticola in the ML tree. In conclusion, the phylogeny of Rheum based on cpDNA trnS-G sequences may serve as a reference for exploring specific patterns of rapid speciation in QTP and similar geographical environment.
To Cite this article:
Weiwei Li and Ailan Wang - Phylogeny of Rheum (Polygonaceae) based on cpDNA trnS-G sequences. Pak. J. Bot., 52(4): DOI: http://dx.doi.org/10.30848/PJB2020-4(43)
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