Adaptation is a fundamental evolutionary process that allows species and populations to cope with changing environments. However, how adaptation operates in natural populations at the level of individual genes and their non-coding DNA environment - the genome? Using genome resequencing of natural Arabidopsis populations coupled with transcriptomics, metabolomics and field and chamber experiments, we aim to uncover how plant genomes respond to a dramatic environmental challenge – the colonization of alpine habitats after the end of ice ages. Multiple pairs of independently adapted populations provide natural replicates that will allow us to find the general trends in the process of natural selection and adaptation. Identification of candidate genes under selection in a plant model genus may also provide important clues for crop breeding aimed at tolerance to environmental challenges.
We recently terminated a long-term transplant experiment in the Austrian Alps to test whether local adaptation involves similar traits in independently adapted alpine populations from different regions when transplanted to the same environment. Seeds of Arabidopsis arenosa plants were collected in 16 natural diploid and tetraploid populations at different elevations from the Alps and Carpathian Mountains and seedlings were transplanted into a low and high-elevation garden. Analysis of the phenotypic data showed clear signs of local adaptation with no obvious difference between the two ploidy levels. In general, we found overall local advantage of foothill and alpine plants when transplanted in their native elevation but the differences may be more or less important depending on the mountain region of origin.
Arabidopsis plant of a foothill (A) and an alpine (B) origin grown at the low-elevation site. Differences in fitness parameters depicted by number of flowers (C) and total dry biomass (D) between populations of foothill (green) and alpine (orange) origin grown in the low- and high-elevation site.
Transposable elements (TEs) may play an important role in response to environmental challenges in plants. Recent studies highlighted that biotic and abiotic stress induced activity of TEs, in particular the retrotransposons belonging to Copia and Gypsy families. Using expression analysis by RNA-seq, we study the activity of TEs between foothill and alpine populations of A. arenosa raised in growth chamber experiments. Preliminary results indicate that some Copia and Gypsy elements are differentially expressed between foothill and alpine ecotypes and are also responsive to changes in temperature and irradiance, factors varying strongly with elevation.
Funding: Junior researcher project of Czech Science Foundation (17-20357Y) & Junior group leader research project of Charles University in Prague (Primus/SCI/35) & FRIPRO Mobility project, Norwegian Research Council (262033)
Team members involved: Guillaume Wos, Magdalena Bohutínská, Doubravka Požárová
Key collaborators on this work are
Karl Hülber (Univ. Vienna)
Christian Parisod (Univ. Bern)