Molecular phylogeny and genetic diversity of some Lepidagathis species (Acanthaceae) based on nuclear and chloroplast regions

Lepidagathis Wild., a pantropical genus belonging to the tribe Barlerieae, contains similar to 147 species. Considerable morphological work has been done on Lepidagathis, but some taxonomical doubts and contrasting interpretations still persist. Molecular analysis is the best tool to resolve the taxonomic doubts, but few nucleotide sequence data are available to date on Lepidagathis. Recently, some phylogenetic and morphological studies have proposed the inclusion of Teliostachya and Lophostachys in Lepidagathis. This work constitutes the first phylogenetic analysis of some Lepidagathis species based on chloroplast and nuclear regions. Both Bayesian and Maximum Likelihood phylogenetic analyses divide studied Lepidagathis species into two main clades, i.e. Clade A and B and place the Indian endemic Lepidagathis in Clade A with strong support. Phylogeny based on combined data resolve Lepidagathis, Barleria, and Crabbea lineages with stronger support than nrITS and cpDNA phylogenies. This phylogenetic study supports previous systematic revisions about the inclusion of Lophostachys and Acanthura species in Lepidagathis as well as the inclusion of Golaea and Acanthostelma into Crabbea species. In conclusion, this study constitutes a baseline molecular phylogeny for Lepidagathis and, in particular, contributes to the knowledge of the genetic diversity of Indian representatives of the genus.