Metabolomics and evolution of chemical characters in the subtribe Espeletiinae (Asteraceae)

Abstract

The northern region of the tropical Andes in South America was subjected to a series of climate fluctuations as a consequence of the recurrent periods of glaciations and inter-glaciations that occurred in the late Pliocene and early Pleistocene, two to five million years ago. This led to the development of a new ecosystem called páramo, which combines the isothermal climatic conditions of the tropical region with the low temperatures characteristic of high elevations. This ecosystem is characterized by a series of climatic and vegetation conditions that make it unique, among which stand out the "Frailejones", a group of ca. 143 species grouped in eight genera that make up the subtribe Espeletiinae (Asteraceae, Millerieae). Due to its high morphological variability and recent speciation, the Frailejones are considered a classic example for studying rapid adaptive radiations and speciation mechanisms in plants. Therefore, the biology, ecology and especially the phylogeny and taxonomy of this group have been the focus of numerous studies in recent years. However, chemically have been poorly studied and there are still many questions concerning the possible correlation between the chemical composition of the subtribe and their taxonomy, morphology, and biogeography. Furthermore, it is unknown if the evolution of chemical characters in this group may help explain its adaptive evolutionary success, considering that recent studies have shown that the chemical composition of the species of the main genus in the subtribe (Espeletia) varies according to their geographical origin, with similar results based on molecular markers. Therefore, this research project aims to investigate species of Espeletiinae through a metabolomic approach by UHPLC-UV-MS and multivariate statistical methods, in order to contribute to the understanding of the secondary metabolism chemistry of this subtribe and its correlation with biological data. Additionally, we intend to perform phylogenetic analyzes with sequences from the literature with the aim of mapping the chemical characters in the evolution of the subtribe and thus determine ancestral states, contributing to the understanding of evolutionary processes that have shaped the current distribution and diversity of secondary metabolites in Espeletiinae. (AU)