The role of genetic and epigenetic changes and trait variation in adaptation of a clonal plant to changing climate

The SeedClim project studies the mechanics of plant adaptation to climate change using a climate grid in western Norway where four levels of annual precipitation (600, 1200, 2000 and 2700 mm) are combined with three levels of mean summer temperatures (7.5, 9.5, and 11.5°C) while keeping all other variables as constant as possible. Within SeedClim, I focused on the study of signatures of adaptive patterns and estimating the adaptive potential of a widespread Graminacea, Festuca rubra. For this I used population and quantitative genetic approaches.

I compared neutral genetic differentiation (F ST ) estimated from anonymous, neutral, SSR markers and putatively adaptive variation (Q ST ) estimated as between population phenotypic variation in natural populations. For most measured traits, Q ST was significantly higher than F ST , suggesting that adaptive, rather than random evolutionary processes, govern population differentiation along the temperature and precipitation gradient. A follow up study focused on the evolutionary potential and evolutionary constraints estimated from classical half-sib design and kinship matrices. I demonstrated a decreased additive genetic variance and increased genetic correlations in warmer and wetter environments, which correspond to future climate change projections for western Norway. Altogether, these results suggest that although present-day populations of F. rubra can adapt to their local climate, this ability could be compromised in future environments which reduce their adaptive potential and increase genetic constraints…