Phylogenetic relationship of Clauseneae (Rutaceae) inferred from plastid and nuclear DNA data and taxonomic implication for some major taxa

8 September 2017

Mou, Fengjuan; Tu, Tie-Yao; Chen, Yi-Zhang; Zhang, Dianxiang

The data matrix in this study contained 91 accessions, 72 species or varieties from 31 genera and two outgroups, including new and extensive sampling of 43 accessions from 29 species or varieties representing four genera in the tribe Clauseneae. Using maximum likelihood (ML) and Bayesian inference (BI) methods, the phylogeny of Clauseneae was reconstructed based on trnL-F, atpB-rbcL and ITS. Six major clades were recognized with strong support in the subfamily Aurantioideae: (1) MICROMELUM Clade: Micromelum; (2) GLYCOSMIS Clade: Glycosmis; (3) BERGERA Clade: Murraya sect. Bergera; (4) CLAUSENA Clade: Clausena; (5) MURRAYA Clade: Murraya sect. Murraya, Merrillia; (6) CITREAE Clade: Citreae. Five genera of Clauseneae don't cluster together; four genera, namely Micromelum, Glycosmis, Clausena and Merrillia are monophyly respectively. However, the genus Murraya s.l. is recovered to be polyphyletic, in that Murraya sect. Bergera and Clausena form a separated branch while Murraya sect. Murraya and Merrillia are clustered into a group and is sister to the tribe Citreae. All members from Citreae are clustered into a natural group. The genus Micromelum is primitive group in this subfamily and more close to Glycosmis. Based on the phylogeny and other morphologic characters, the taxonomy of some major species from Clauseneae was also discussed here. The current tribal and generic classification need further revision, and additional studies are advisable before carrying out further taxonomic changes.