Genômica de populações e diversidade adaptativa do marolo (Annona crassiflora Mart.) ao longo do Cerrado brasileiro

Abstract

The Cerrado is a major South American phytogeographic domain, stretching across reasonably heterogeneous environments and holding considerable species richness. Despite that, it is also one of the most degraded domains in Brazil, surpassing the Amazon. Annona crassiflora, or marolo, is a typical species of the Cerrado, with ample distribution and potential for restoration efforts. In this study, we use a combination of population genomics and landscape genomics approaches to investigate a native species distributed throughout a large portion of the Cerrado’s territory, including northern regions, which are poorly studied. We analyzed both neutral and adaptive genetic diversities, to better understand patterns for the species and for the whole Cerrado, in an attempt to obtain useful information about the influence of the environment on the evolutionary history of the domain. We used neutral loci to assess genetic structure and association tests to identify potentially adaptive SNPs based on leaf morphology data and climatic and soil composition variables, connecting phenotype, genotype and environment. The neutral genetic structure patterns found were generally concordant with previous studies, evidencing the differentiation between eastern and western Cerrado, although our results highlight an important divergence of the northern populations. In addition, we observed high diversity in the southwest, reinforcing the possible existence of refugia in the area. We found a large number of putative adaptive SNPs, and the majority of the adaptive diversity correlates to climatic variables, mainly water availability. We also observed small differences between neutral and adaptive structures, mostly related to climatic gradients within neutral clusters. Our results contribute to the understanding of the evolutionary history of the Cerrado, evidencing the importance of natural selection to population differentiation, and provide relevant information to the domain’s conservation efforts that take into consideration the adaptive potential of its species in the face of climate change.