Ecological and functional genomics of plant adaptation

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One of biology's major goals is to describe understand adaptive evolution on multiple levels of organization: from the genes and mutations involved, to their effects on gene expression and phenotypes, to how those traits function in a realistic ecological context. One area to address this challenge is in the life history and developmental transition from vegetative growth to flowering, which is often under geographically variable selection due to climatic variation and seasonality. We have investigated this in the annual plant, Arabidopsis thaliana, which in addition to being the pre-eminent model system for plant biology, genomics, and genetics, is also in the same family as the important crop, Canola. The genetic and genomic resources for Arabidopsis are being increasingly leveraged for studies in the ecology, evolution, and genetics of adaptation.***Arabidopsis thaliana invaded North America, and appears to show evidence of rapid, adaptive evolution. Recent work in our group has identified 53 novel candidate genes underlying flowering time differentiation in the introduced range. None of these loci have been previously implicated as being involved in flowering time variation in Arabidopsis, suggesting that post-introduction evolution has used novel genetic mechanisms.However, these candidates require genetic and ecological validation. I will investigate the phenotypic, ecological, evolutionary, and transcriptomic consequences of variation at these candidate genes. Combining knockout experiments, studies of near-isogenic lines, ecological studies, and transcriptomics we will allow a comprehensive investigation of the effect sizes, dominance, and ecological consequences of variation at these genes. My specific aims are to: 1) Verify the phenotypic effects of these genes, using tDNA knockout lines, 2) Create near isogenic lines to estimate effect sizes and dominance of naturally occurring mutations that these genes, (3) Perform field experiments to validate their effects in ecologically realistic settings, and (4) Examine their contribution to gene expression variation, and the role of expression variation in within-population variation in flowering time.******The proposed work will support training several HQP in the rapidly expanding areas of ecological and evolutionary genomics, and advance our knowledge of flowering time, plant reproduction, and the genetics of invasive species because it evaluates the roles of molecular genetic and environmental variation in shaping complex traits. The results are likely to be of great importance in understanding adaptive responses of species to biological invasion and climate change.**