Genomic Variation the Threatened Palm Euterpe edulis (Martius) Along Altitudinal Gradients of the Atlantic Forest

Altitudinal climatic gradients may influence adaptive characteristics of plants leading to genetic divergence of populations. Under different selective pressures the allele frequencies at loci among populations may become significantly different and result in local adaptation. In this study we used SNPs to investigate the genomic variation of Euterpe edulis populations across an altitudinal gradient in Serra do Mar mountains, located in Southeast Brazil. A ddRAD genomic library was prepared for 24 adults individuals from four natural populations, with altitudes ranging from the sea level up to 1,100 m. The ddRAD library generated 1,040 high-quality SNPs that allowed the estimation of genomic diversity and differentiation. Genomic diversity was not affected by altitude, measures were similar for E. edulis populations (H_E ranging from 0.17 to 0.19 and A_R ranging from 1.38 to 1.42). The inbreeding coefficient was negative for all populations, again with no correlation with different altitudes. The population located at the sea level was the most differentiated from the other populations studied, as indicated by the pairwise Fst estimates and the multivariate analysis. Further analyses with a larger number of individuals are being carried out to identify outlier loci putatively under selection that may evidence the existence of local adaptation to low altitude in Serra do Mar altitudinal gradient. Characterizing the adaptive variation is fundamental to predict the vulnerability of plants to respond to environmental changes.