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FRIMEDBIO-Fri prosj.st. med.,helse,biol

Parallel adaptation to changing environments in wild Arabidopsis populations

Alternative title: Parallell tilpasning til miljøendringer i ville bestander av modellplanten Arabidopsis

Awarded: NOK 3.1 mill.

Adaptation is a fundamental evolutionary process that allows species and populations to cope with changing environments. However, little is still known about how adaptation operates in natural populations at the level of individual genes and their non-coding DNA environment - the genome. Repeatedly originated alpine populations in the genetically well-characterized plant model genus Arabidopsis are well suited to address this question using an interdisciplinary approach. Using DNA sequencing over whole genomes of natural Arabidopsis populations coupled with field experiments, the project aims to uncover how plant genomes respond to a dramatic environmental challenge, such as the colonization of alpine habitats. During the research stay in Austria, we transplanted plants originating from alpine and foothill conditions to their home vs. foreign elevations and observed significant differences in fitness suggesting that the alpine populations are locally adapted. Analysis of genomic data supported multiple parallel origins of the distinct alpine ecotype in four distinct mountain ranges, and allowed to identify candidate genes linked with plant growth and development that have repeatedly been target of selection in different mountain ranges. Using the independent origins we addressed general question on evolutionary predictability and demonstrate a strong link between the evolutionary distance of lineages, availability of genetic variation standing in the foothill ancestors and subsequent ability to evolve parallel genetic solution to alpine stress. We conclude that adaptive evolution could be well predictable when lineages are closely related but contingent in divergent lineages even if they face similar environmental challenges. Alltogether our results document remarkable evolutionary plasticity of plants when facing harsh alpine climate.

The results contribute to our understanding of plant adaptation under environmental challenges. By focusing on high-altitude environments, a harsh ecological transition, the results (both theoretical concepts and actual list of adaptive genes and their potential transcriptomic consequences) may inform predictions of the impact of climate change on biodiversity. Our genomic investigation provides a first empirical demonstration of divergence-dependency of repeated genome evolution, exemplified by five-fold independent alpine colonisation. Consequently, our results broadly inform on how predictable plant genome evolution may be, what brings general implications for pest control, nature conservation and predictions on genome evolution. The results shall stimulate research in the Arabidopsis scientific community by providing foundations for follow-up studies on the molecular function of the identified loci, including targets for further crop breeding and temperature resilience.

Adaptation is a fundamental evolutionary process that allows species and populations to cope with changing environment. However, little is still known about the genomic background of adaptation in natural populations. Repeatedly originated alpine ecotypes of plant model Arabidopsis arenosa, so far not subjected to any ecological and/or genomic study, provide exceptional opportunity to characterize how genome responds to dramatic environmental challenge such as was the recent colonization of postglacial alpine habitats. Using comprehensive whole-genome scans of multiple populations coupled with manipulative experiment, I aim at identifying genome-wide set of loci that are consistently associated with alpine phenotype and characterizing genomic landscape of adaptation of wild Arabidopsis populations. By comparing multiple pairs of independently originated ecotypes occupying similar environment, this project will also address role of generality in process of selection and adaptation. Identification of candidate loci that got repeatedly under selection in a plant model genus may also provide important clues for rational crop breeding aimed at tolerance to environmental challenges. The host institution, largely focused on evolution and ecology of alpine organisms ideally matches the project objectives and will provide me in-depth training in relevant fields of ecology and genomics. The project will significantly improve my skills in leading-edge scientific methods (advanced analyses of high-throughput sequence data, design and evaluation of ecological experiments, ecophysiology and metabolomics) and will strengthen my scientific independence through training in project management and international collaboration.

Funding scheme:

FRIMEDBIO-Fri prosj.st. med.,helse,biol

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