Genomic basis and evolutionary potential for extreme drought adaptation in Arabidopsis thaliana

Abstract

Because earth is currently experiencing dramatic climate change, it is of critical interest to understand how species will respond to it. The chance of a species to withstand climate change will likely depend on the diversity within the species and, particularly, whether there are subpopulations that are already adapted to extreme environments. However, most predictive studies ignore that species comprise genetically diverse individuals. We have identified genetic variants in Arabidopsis thaliana that are associated with survival of an extreme drought event, a major consequence of global warming. Subsequently, we determined how these variants are distributed across the native range of the species. Genetic alleles conferring higher drought survival showed signatures of polygenic adaptation, and were more frequently found in Mediterranean and Scandinavian regions. Using geo-environmental models, we predicted that Central European, but not Mediterranean, populations might lag behind in adaptation by the end of the 21st century. Further analyses showed that a population decline could nevertheless be compensated by natural selection acting efficiently over standing variation or by migration of adapted individuals from populations at the margins of the species’ distribution. These findings highlight the importance of within-species genetic heterogeneity in facilitating an evolutionary response to a changing climate.

Unique genetic signatures of local adaptation over space and time for diapause, an ecologically relevant complex trait, inDrosophila melanogaster

“…In gypsy moths, SNPs associated with three ecologically relevant traits have consistent clinal signals [101], and in corals, SNPs associated with heat tolerance are more common in warmer reefs and in warmer microclimates within a single reef [102]. Drought-associated SNPs also show spatial variation in European populations of Arabidopsis thaliana [103], and models suggest that those populations with more drought-tolerance alleles may adapt to global warming more effectively. Therefore, in addition to elucidating genetic mechanisms of local adaptation, the ability to detect polygenic adaptation of ecologically relevant traits over space is important for predicting population-level changes in response to climate change.…”

The Earth BioGenome project: opportunities and challenges for plant genomics and conservation

“…We note that both the pace of extinction and countervailing conservation efforts are affected by within‐species diversity (Jump et al , ; Exposito‐Alonso et al , ). In fact, geographic distributions of about 50% of plant and animal species surveyed are already shrinking (Wiens, ).…”

Effects of two centuries of global environmental variation on phenology and physiology of Arabidopsis thaliana

“…Arabidopsis displays substantial genetic diversity in environmental response between genotypes from different regions (e.g., Exposito-Alonso et al, 2018;Lasky, Forester, & Reimherr, 2018). Thus, we employed a regression model with spatially varying coefficients (GAM) to account for regional differences in responses to environment, much of which may have a genetic component (Wheeler & Waller, 2009;Wood, 2006).…”