Abstract
As climate changes, understanding the genetic basis of local adaptation
in plants becomes an ever more pressing issue. Combining
Genotype-Environment Association (GEA) with Genotype-Phenotype
Association (GPA) analysis has an exciting potential to uncover the
genetic basis of environmental responses. We use these approaches to
identify genetic variants linked to local adaptation to drought inPinus ponderosa . Over 4 million SNPs were identified using 223
individuals from across the Sierra Nevada of California. We found 1458
associated with five largely uncorrelated climate variables, with the
largest number (1151) associated with April 1stsnowpack. We also conducted a greenhouse study with various
drought-tolerance traits measured in seedlings grown in control and
drought treatments. 817 SNPs were associated with control-condition
trait values, while 1154 were associated with responsiveness of these
traits to drought.
While
no individual SNPs were associated with both the environmental variables
and the measured traits, several annotated genes were associated with
both, particularly those involved in cell wall formation, biotic and
abiotic stress responses, and ubiquitination. However, the functions of
many of the associated genes have not yet been determined due to the
lack of gene annotation information for conifers. Future studies are
needed to assess the developmental roles and ecological significance of
these unknown genes.
Keywords: climate change, adaptive genetic variation,
environmental association, phenotypic association, GBS, SNP