Chemistry of the subtribe Espeletiinae (Asteraceae) and its correlation with phylogenetic data: an in silico chemosystematic approach

Abstract

The subtribe Espeletiinae (Asteraceae) constitutes a recently diversified group endemic to the South American Andes. Due to its impressive morphological diversity and remarkable success in the páramo ecosystem, the subtribe has been the focus of intensive research. However, disagreement persists over the taxonomic subdivisions of Espeletiinae as well as its phylogeny. Chemically, the group is characterized by the presence of ent-kaurane diterpenes, but this information is currently dispersed and fragmented. Considering that chemical markers could aid in developing a deeper understanding of the taxonomy of Espeletiinae, the aim of this study was to (1) review the secondary metabolite chemistry of this subtribe, (2) discuss taxonomic implications and (3) perform phylogenetic analyses using chemical data to assess similarities and differences among the chemical and molecular phylogenies. Interestingly, our phylogenetic analyses using chemical data showed a characteristic geographic structure, with one grade containing mostly Venezuelan taxa and one clade composed mainly of Colombian species, which is in agreement with the molecular phylogeny of the subtribe. Our results suggest that chemical markers can be used to infer chemotaxonomic and chemosystematic relationships in Espeletiinae and offer the first report of the use of Bayesian inference and maximum likelihood methods with chemical data.