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

Using sequences of the nuclear ribosomal ITS region as well as the chloroplast DNA <italic>trn</italic>L‐<italic>trn</italic>F and <italic>atp</italic>B‐<italic>rbc</italic>L regions, this study aims to provide further insight into the phylogenetic relationships within Clauseneae and its relationship to Citreae (Rutaceae). Using maximum likelihood (ML) and Bayesian inference (BI), we reconstructed the phylogeny of Clauseneae based on <italic>trn</italic>L‐F, <italic>atp</italic>B‐<italic>rbc</italic>L and ITS sequences. Our data matrix contained 91 accessions, representing 72 species and varieties from 31 genera and two outgroups, including new and extensive sampling of species and varieties representing four genera in the tribe Clauseneae. In the subfamily Aurantioideae, six major clades were resolved with strong support: 1) Micromelum clade: <italic>Micromelum</italic>; 2) Glycosmis clade: <italic>Glycosmis</italic>; 3) Bergera clade: <italic>Murraya</italic> sect. <italic>Bergera</italic>; 4) Clausena clade: <italic>Clausena</italic>; 5) Murraya clade: <italic>Murraya</italic> sect. <italic>Murraya</italic> + <italic>Merrillia</italic>; 6) Citreae clade: Citreae. <italic>Micromelum</italic>,<italic> Glycosmis</italic>, <italic>Clausena</italic> and<italic> Merrillia</italic> were confirmed as monophyletic. In contrast, <italic>Murraya</italic> s.l. was reconstructed as polyphyletic. <italic>Murraya</italic> sect. <italic>Bergera</italic> clustered with <italic>Clausena</italic> while <italic>Murraya</italic> sect. <italic>Murraya</italic> and <italic>Merrillia</italic> together formed a clade that is sister to the tribe Citreae. All members from Citreae were clustered into a natural group. The genus <italic>Micromelum</italic> was found to be primitive in this subfamily and more close to <italic>Glycosmis</italic>. Based on the phylogeny and morphological characters, we discuss the taxonomy of some members of Clauseneae and conclude that the current tribal and generic classification need further revision. [ABSTRACT FROM AUTHOR]