Phylogenetic relationships, diversification and expansion of chili peppers (Capsicum, Solanaceae)

CARRIZO GARCÍA C.; BARFUSS MHJ; SEHR EM; BARBOZA GE; SAMUEL R; MOSCONE EA; EHRENDORFER F

ANNALS OF BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2016

0305-7364

Background and Aims. Capsicum (Solanaceae), native to the tropical and temperate Americas, comprises the well-known sweet and hot chili peppers and several wild species. So far, only partial taxonomic and phylogenetic analyses have been done for the genus. Here,the phylogenetic relationships between nearly all taxa of Capsicum were explored to test the monophyly of the genus and toobtain a better knowledge of species relationships, diversification and expansion.Methods. Thirty-four Capsicum species (out of ca. 35) were sampled. Maximum Parsimony and Bayesian Inference analyses were performed using two plastid markers matK and psbA-trnH and one single-copy nuclear gene (waxy). The evolutionary changes of nine key features were reconstructed following the parsimony ancestral states method. Ancestral areas were reconstructed through a Bayesian MCMC analysis.Key Results. Capsicum forms a monophyletic superclade, with Lycianthes as sister group,following both phylogenetic approaches. Eleven well supported clades (four ofthem monotypic) can be recognized within Capsicum, although some interspecific relationships need further analysis. A few features are useful to characterize different clades (e.g. fruit anatomy, chromosome basenumber) while some others are highly homoplastic (e.g. seed colour). The origin of Capsicum is postulated in an area along the Andes of W-NW South America. The expansion of the genus has followed a clockwise direction around the Amazon basin, towards Central and SE Brazil,then back to W South America, and finally northwards to Central America.Conclusions. New insights are provided regarding interspecific relationships, character evolution and geographic origin and expansion of Capsicum. A clearly distinct basal clade can be distinguished, centred in W-NW South America. Subsequent rapid speciation has led to the origin of the remaining clades. The diversification of Capsicum has culminated in the origin of the main cultivated species in several regionsof South to Central America.