Data from: Exploring genomic variation associated with drought stress in Picea mariana populations

Predicted increases in drought and heat stress will likely induce shifts
in species bioclimatic envelopes. Genetic variants adapted to water
limitation may prove pivotal for species response under scenarios of
increasing drought. In this study, we aimed to explore this hypothesis by
investigating genetic variation in 16 populations of black spruce (Picea
mariana) in relation to climate variables in Alaska. A total of 520 single
nucleotide polymorphisms (SNPs) were genotyped for 158 trees sampled from
areas of contrasting climate regimes. We used multivariate and univariate
genotype-by-environment approaches along with available gene annotations
to investigate the relationship between climate and genetic variation
among sampled populations. Nine SNPs were identified as having a
significant association with climate, of which five were related to
drought stress response. Outlier SNPs with respect to the overall
environment were significantly overrepresented for several biological
functions relevant for coping with variable hydric regimes, including
osmotic stress response. This genomic imprint is consistent with local
adaptation of black spruce to drought stress. These results suggest that
natural selection acting on standing variation prompts local adaptation in
forest stands facing water limitation. Improved understanding of possible
adaptive responses could inform our projections about future forest
dynamics and help prioritize populations that harbor valuable genetic
diversity for conservation.