Genomic responses to climate: Understanding local adaptation in the Andean tree species Nothofagus pumilio and implications for a changing world

SEKELY, JILL; MARCHELLI, PAULA; ARANA, VERÓNICA; DAUPHIN, BENJAMIN; MATTERA, MARÍA GABRIELA; PASTORINO, MARIO; SCOTTI, IVAN; SOLIANI, CAROLINA; HEER, KATRIN; OPGENOORTH, LARS

PLANTS, PEOPLE, PLANET

Willey

Año: 2024

2572-2611

Nothofagus pumilio is a foundation tree species that inhabits a 2000-km-long range inthe southern Andes, a region with two perpendicular environmental gradients:temperature and photoperiod (North–South), and precipitation (West–East). Weinvestigated local adaptation patterns by searching for relationships betweenenvironmental clines and signatures of adaptation in candidate genes related tostress response, growth, and phenology. Using a paired site sampling design within alandscape genome analysis, we analyzed 493 adult N. pumilio trees in 20 samplingsites across the species' latitudinal range. We screened 47,336 single nucleotide polymorphism(SNP) loci in 1632 contigs (i.e., coding regions along the genome). Populationstructure and genetic diversity analyses preceded four genome scan analysesusing genetic and environmental data. Population structure and genetic diversity aremainly oriented along the latitude axis. Genome scans identified 445 outlier SNPs,which are loci showing signatures of selection. Temperature and photoperiodvariables were associated with notably more outliers than precipitation. However, the most frequent biological functions among genes were water deprivation responseand cold response, suggesting that stress response is comprised of complex and polygenictraits that are affected by many environmental variables. Our findings suggestthat N. pumilio shows signatures of local adaptation to extant climate conditions,including temperature, photoperiod, and precipitation. However, climate change islikely to alter existing relationships among environmental conditions to which thisspecies is currently adapted. These changes may have unpredictable consequencesfor the species' future survival, adaptation potential, and the people who dependupon these forests.