Phylogeographic and phylogenetic analyses of selected set of wild and naturalized Solanum spp. in Sri Lanka

Abstract

Solanum spp. encompass a greater share of the biodiversity in the world. Sri Lanka, one of the biodiversity hotspots in the world, is the home for wide range of Solanum spp. which have been named and morphologically characterized.However, their origins and times of origin have not yet been resolved. Hence, this study was conducted to identify the origins and origination events of 13 wild and naturalized Solanum spp. found in Sri Lanka, using DNA barcoding locus matK in comparison to worldwide Solanum spp. with phylogenetics and divergence dating approaches. In this study, 13 Sri Lankan Solanum spp. were separated into four defined phylogenetic groups viz., Old world, Morelloids, Acanthophora and Trova. The studied Sri Lankan Solanum spp. would have been originated in Africa 2.007 million years ago (MYA) in the Pleistocene epoch through mammalian migration from Mediterranean land bridges. The Australian relatives of Sri Lankan Solanum spp. would have been colonized from South Asia through South East Asia. The floristic connectivity in Pleistocene epoch may have introduced Asian Solanum spp. to South East Asia where mid Miocenic collisions between Australian and Asian plates as well as over water Long Distance Dispersal (LDD) may have caused these species to colonize in Australia. Our analysis demonstrated that most of the Solanum spp. found in Sri Lanka were introduced from India during the Pleistocene ice age. We suggest that Pre Pleistocene migrations of Solanum spp. such as S. nigrum may have occurred through overwater LDD.