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Abstract title Adaptive remodeling of the transcriptional response to drought stress in Arabidopsis lyrata
Author Juliette De Meaux, Cologne, Germany (Presenting author)
Topic 19 Evolution of gene expression regulation
Abstract text

To describe how stress responses evolve, we undertook a time serie analysis of plant transcriptome responses to progressive dehydration in the species Arabidopsis lyrata, which is robust to drought stress, and compared it to the response displayed by the more sensitive sister species A. halleri. Our results show that while A. halleri displays a response that converges towards an ancestral response type, A. lyrata has evolved a novel transcription profile. Trans-acting mutations predominate at early steps of the response, but as it progresses, interspecific divergences is becoming increasingly sustained by cis-acting mutations. To investigate the footprint of polygenic selection on the timing and dynamics of the expression response, we analyzed the distribution of cis-acting mutations derived in each lineage, an approach that we had previously used to demonstrate selection on heavy metal genes in A. halleri. We show that the response displayed by A. lyrata 6h after initiation of the stress carries the signature of polygenic selection on the GO category „regulation of response to stress“. We contrast our results with a population genomics survey of selection coefficients throughout the genome. Our work illustrates the polygenic nature of adaptation in complex traits.