Genomics of Climate Adaptation in Pinus Lambertiana

The largest pine tree in the world, sugar pine, also has one the largest genomes ever sequenced in any plant species. The reference genome, transcriptome, and SNP markers developed for the species have been used to support breeding disease resistant trees and answer questions related to genome obesity. These resources also create an opportunity to explore associations between genetic variation and environmental variables. By combining ordination and association techniques such as PCA, MLM, and RDA, we identified markers and genes associated with environmental variation across the Sugar Pine species range. Most of the genes identified by our analysis were associated with precipitation though temperature and continentality were also found to be associated with putatively adaptive genes. The results of the PCA and environmental correlations demonstrated explicit groupings among the environmental variables. Functional annotations for these genes were primarily related to signal transduction and disease resistance, but annotations related to biotic and abiotic stress were also identified. Results further provide insight into the geographic pattern of environmentally correlated genetic variation in the species. These findings may provide important insights to guide management strategies looking to maintain the species through ongoing changes in climate and fire regimes.