Adaptation represents key evolutionary mechanism, which allows species and populations to succeed in a variable environment. Hostile serpentine soils are among the strongest triggers for adaptation in plants. This chemically extreme substrate provides multiple challenges to plant life, including extremely low Ca:Mg ratio and elevated levels of toxic metals. Therefore, serpentine barrens provide a powerful model for studying multi-challenge adaptations. Moreover, the island-like distribution of serpentines can trigger parallel evolution at the level of both genome and phenotype.
In multiple serpentine / non-serpentine pairs of Arabidopsis arenosa populations we study substrate adaptive evolution using population genomics (demographic reconstruction, genome scanning for selection candidates) and multi-trait phenotyping including high-throughput analysis of metal uptake. By sampling multiple lineages, we ask if serpentine populations of A. arenosa from central Europe originated by means of parallel adaptation. First results have shown multiple colonization events of serpentine barrens as well as several common candidate genes for selection among serpentine populations were identified. Furthermore, the candidate genes seem to be relevant to serpentines, e.g. genes, which are involved in dehydration tolerance and ion homeostasis traits.
In a follow-up, we will ask if adaptive introgression from closely related species A. lyrata played a role in repeated cases of serpentine adaptation. In collaboration with C. Parisod we also are going to further test generality of our findings using other Brassicecae species frequently found on and off serpentines, Biscutella leavigata.
Funding: Junior group leader research project of Charles University in Prague (Primus/SCI/35)
Key collaborators on this work are
Levi Yant (University of Notingham, UK)
Christian Parisod (University of Bern, Switzerland)