Data from: Genome-wide association mapping within a local Arabidopsis thaliana population more fully reveals the genetic architecture for defensive metabolite diversity

A paradoxical finding from genome-wide association studies (GWAS) in
plants is that variation in metabolite profiles typically maps to a small
number of loci, despite the complexity of underlying biosynthetic
pathways. This discrepancy may partially arise from limitations presented
by geographically diverse mapping panels. Properties of metabolic pathways
that impede GWAS by diluting the additive effect of a causal variant, such
as allelic and genic heterogeneity and epistasis, would be expected to
increase in severity with the geographic range of the mapping panel. We
hypothesized that a population from a single locality would reveal an
expanded set of associated loci. We tested this in a French Arabidopsis
thaliana population (< 1 km transect) by profiling and conducting
GWAS for glucosinolates, a suite of defensive metabolites that have been
studied in depth through functional and genetic mapping approaches. For
two distinct classes of glucosinolates, we discovered more associations at
biosynthetic loci than previous GWAS with continental-scale mapping
panels. Candidate genes underlying novel associations were supported by
concordance between their observed effects in the TOU-A population and
previous functional genetic and biochemical characterization. Local
populations complement geographically diverse mapping panels to reveal a
more complete genetic architecture for metabolic traits.