Assessing genetic structure of Eugenia uniflora L. populations along an environmental gradient using a novel set of SSR markers

Abstract

Gradients in biodiversity are often considered a result of environmental variables like temperature, precipitation, ecological disturbance regimes, and species coexistence. This study aimed at investigating the genetic diversity and structure of natural populations of Eugenia uniflora growing in two different biomes in southern Brazil (Atlantic Forest and Pampa biomes), as well as in the transition zone between them. A novel set of 11 SSR loci from E. uniflora was validated and employed to test the hypothesis that the allelic composition of the populations changes gradually along the environmental gradient sampled, with a characteristic genetic structure within each biome and an intermediary allelic composition in the transition zone. The results revealed high polymorphism of the validated markers and significant genetic structure of the different populations. The main source of genetic variation observed is the individual samples, but there was a considerable amount of variation among populations, and regions. We suggested that the genetic structure of the studied populations presents distinct patterns which may be related to adaptation to local environmental conditions, or at least related to the transition among them. Our study provides evidence that even environments neglected regarding the information on their biodiversity and the transition zones may hold important levels of genetic diversity. Thus, the distribution of genetic diversity should be interpreted in the light of the life traits of the species and the local environment since valuable diversity may be found both in a hotspot of diversity and in neglected forest formations.