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Abstract

Genetic variation, environment and demography intersect to shape Arabidopsis defense metabolite variation across Europe
Ella Katz1, Jia-Jie Li1, Benjamin Jaegle2, Haim Ashkenazy3, Clement Bagaza4, Samuel Holden4, Ruthie Angelovici4, Daniel Kliebenstein1
1UC Davis, 2Gregor Mendel Institute, 3Max Planck Institute for Developmental Biology, 4University of Missouri, Columbia
Presenter: Ella Katz
Plants produce diverse metabolites to cope with the challenges presented by complex and ever-changing environments. These challenges drive the diversification of specialized metabolites within and between plant species. However, we are just beginning to understand how frequently new alleles arise controlling specialized metabolite diversity and how the geographic distribution of these alleles may be structured by ecological and demographic pressures. Here we measure the variation in specialized metabolites across a population of 797 natural Arabidopsis thaliana accessions. We show a combination of geography, environmental parameters, demography, and different genetic processes all combine to influence the specific chemotypes and their distribution. This showed that causal loci in specialized metabolism contain frequent independently generated alleles using both SNPs and structural variation with patterns suggesting potential within species convergence. Further, the distribution of the alleles and chemotypes across Europe is likely shaped by an interaction of demography with non-linear selection processes that potentially vary across geography. This indicates that local adaptation of specialized metabolism may not follow linear gradients at a continental scale. This provides a new perspective about the complexity of the selective forces and mechanisms that shape the generation and distribution of allelic variation that may influence local adaptation.