Salacioideae is one of the subfamilies of the family Celastraceae. Salacia is a rare, endangered, and threatened genus found in India. Salacia is one of the Western Ghats’ endemic species. Salacia species segregation and delimitation are difficult to achieve just based on taxonomic identification. The current research is an attempt to conduct a complete investigation into molecular phylogeny, estimation of age, and geographical implications of Salacia species. Salacia sp. Internal transcribed spacers (ITS), matK, and rcbL sequences from the Western Ghats of Karnataka, Kerala, and sequences from GenBank were utilized for the present study. Bayesian inference analysis (BI) and maximum likelihood (ML) to construct a phylogenetic tree using MrBayes and RAxML software. BI tree was used to calculate the divergence age of the Salacia species. Utilizing RASP v.2.0b geographic inferences were analyzed. A Well resolved phylogenetic tree was observed in the ITS and ITS + matK + rbcl concatenated sequence of the old world (OWC) and new world (NWC) samples forming two major clades. However, a poorly resolved phylogenetic tree was observed in the matK + rbcL sequences. The crown age of OWC and NWC was 9.82 Ma and 17.4 Ma, respectively. Madagascar and East Africa Salacia species had common tip node age of 3.13 Ma. Phylogeographic analysis suggests a total of 50 dispersals and 25 vicariance events. Phylogeographic analysis reveals the Salacia species could have originated from Southeast Asia. The endemism and diversity of Salacia species in the Western Ghats are explained by the fact that Salacia species from various geographic regions were positioned discordantly in the phylogenetic trees, demonstrating a high level of sequence similarity and congruence.
Key words: Biogeographic implication, DNA barcode, Phylogeny, Salacia species.
|
