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Sinosenecio yangii (Asteraceae), a new species from Guizhou, China

Citation

Zhou, Qiang et al. (2022), Sinosenecio yangii (Asteraceae), a new species from Guizhou, China, Dryad, Dataset, https://doi.org/10.5061/dryad.d7wm37q4g

Abstract

A new species Sinosenecio yangii D.G. Zhang & Q. Zhou (Asteraceae, Senecioneae) from Guizhou Province, China, is described and illustrated based on its morphological characteristics and molecular evidence. It closely resembles S. confervifer and S. guangxiensis, the former in the scapigerous habit and smooth and glabrous achene surface, the latter in the calyculate involucre and purple abaxial leaf surface, and both in the shape and indumentum of leaf lamina, but differs markedly from the latter two in having fewer capitula and epappose achenes. Phylogenetic analysis based on nrITS and ndhC-trnV sequences shows that this new species belongs to the S. latouchei clade and is sister to S. guangxiensis with moderate support.

Methods

Morphological observation 

Morphological examination and comparison of the new species with S. confervifer and S. guangxiensis were based on fresh materials and herbarium specimens. Chromosome observation was conducted according to Meng et al. (2010).

Molecular analyses

To test the phylogenetic affiliation of S. yangii, we carried out a phylogenetic analysis based on a combined matrix of ITS and ndhC-trnV sequences. The matrix contained 23 accessions from 20 species, including the new species, 16 species of the S. oldhamianus group, two of Nemosenecio, and an outgroup, Tephroseris flammea (Turcz. ex DC.) Holub. The ITS and ndhC-trnV of S. yangii were sequenced in this study and the rest were downloaded from GenBank. The GenBank accession numbers are listed in Appendix 1. Total DNA was extracted from dried leaves using Plant Genomic DNA Kit DP305 (Beijing, China) and used as the template for polymerase chain reaction (PCR). The primers used in this study are listed in Table 1. Sequences obtained were edited using Sequencher-5.4.5 and then combined by Sequence Matrix-1.9 (Vaidya et al. 2011). Multi-sequence alignment and manual adjustment were conducted using the programme CLUSTAL_W in Mega-X64 (Rédei 2008) and gaps were treated as missing data.

Phylogenetic trees were constructed using Bayesian Inference (BI) and Maximum Likelihood (ML) in CIPRES Portal (https://www.phylo.org/portal2). BI and ML analyses were performed using MrBayes version-3.2 (Ronquist et al. 2012) and RAxML-8.2.10 (Stamatakis 2014), respectively. For BI analysis, GTR+G was selected as the best-fitting model using Akaike information criterion (AIC) in JmodelTest 2-2.1.6 (Posada 2008). The Markov chain Monte Carlo analyses were run with four simultaneous chains of 10,000,000 generations sampling one tree every 1,000 generations. After the first 25% of trees were discarded as burn-in, the remaining trees were used to construct a majority-rule consensus tree with Bayesian posterior probabilities. ML analysis was performed with GTRCAT model, and support values were calculated with 1,000 bootstrap replicates using a fast bootstrapping algorithm (Stamatakis et al. 2008).

Funding

National Natural Science Foundation of China, Award: 31860117