Local adaptation to an altitudinal cline of populations of Pitcairnia flammea Lindl (Bromeliaceae) species complex from the southeast of Brazil

Abstract

Local adaptation may promote the genetic divergence of a population culminating in na event of ecological speciation. Previous studies suggest that populations of the Pitcairnia flammea (Bromeliaceae) species complex are diverging because of local adaptation to altitude and temperature. The aim of this study is to understand how the process of local adaptation to an altitudinal gradient has contributed to the genetic divergence of Pitcairnia flammea populations in southeastern of Brazil. For this purpose, we intend to assemble and annotate the chromosomal level genome of the species, using PacBio HiFi and Omni-C sequences. Afterwards, some individuals distributed through an altitudinal cline will be resequenced in a medium coverage to characterize the whole gene pool of the species, that is, the pangenome. Once the pangenoma is assembled, a population genomic approach will be carried out in order to: (I) characterize the structural variations present in the pangenome of P. flammea and observe how they are structured among its populations; (II) discern the role of each evolutionary force in the process of population genetic divergence and consequent speciation of P. flammea populations in the altitudinal cline in the Atlantic Forest; and (III) identify which is the genetic basis responsible for the local adaptations of these populations and how the environment has influenced this process. In this way, this study aims to understand how the environment can promote the genetic divergence of locally adapted populations, thus contributing to the elucidation of the first steps of the speciation process in one of the most biodiverse areas in the world and to make predictions about the resilience of species in the face of climate changes.