Population differentiation and phylogeography in Lycianthes moziniana (Solanaceae: Capsiceae), a perennial herb endemic to the Mexican Transition Zone

Abstract

Abstract Lycianthes moziniana (Solanaceae: Capsiceae) is a perennial herb with edible fruits that is endemic to Mexico. Three varieties are recognized, all known in the Mexican Transition Zone. Lycianthes moziniana var. margaretiana grows in the Sierra Madre Oriental, whereas L. moziniana var. moziniana is common along the Trans-Mexican Volcanic Belt and in the Sierra Madre Occidental. Lycianthes moziniana var. oaxacana is found exclusively in the Sierra Madre del Sur. The Mexican Transition Zone is a complex geological, climatic and biogeographical area, the result of tectonic and volcanic activity that has promoted genetic divergence and speciation. We determined the genetic variation and structure of L. moziniana. Using phylogeographical approaches, we described the demographic history and evolutionary processes leading its divergence. The intergenic spacers rpl32-trnL and ycf1 were sequenced for 133 individuals pertaining to 15 populations. The genealogical relationships were analysed using haplotype networks. Finally, based on ecological niche models, we inferred the palaeodistribution of L. moziniana during the Pleistocene. The genetic differences and the haplogroups matched the three described varieties. Geological and climatic events of the Mexican Transition Zone facilitated these results. The Trans-Mexican Volcanic Belt isolated the populations of the Sierra Madre Oriental and the Sierra Madre del Sur, while allowing the migration to the Sierra Madre Occidental, during the middle Holocene.