PT  - JOURNAL ARTICLE
AU  - AD Gloss
AU  - B Brachi
AU  - MJ Feldmann
AU  - SC Groen
AU  - C Bartoli
AU  - J Gouzy
AU  - ER LaPlante
AU  - CG Meyer
AU  - HS Pyon
AU  - SC Rogan
AU  - F Roux
AU  - J Bergelson
AU  - NK Whiteman
TI  - Genetic variants affecting plant size and chemical defenses jointly shape herbivory in <em>Arabidopsis</em>
AID  - 10.1101/156299
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 156299
4099  - http://biorxiv.org/content/early/2017/06/27/156299.short
4100  - http://biorxiv.org/content/early/2017/06/27/156299.full
AB  - Herbivorous insects exhibit strong feeding preferences when choosing among plant genotypes, yet experiments to map loci mediating plant susceptibility to herbivory rarely incorporate host choice. To address this gap, we applied genome-wide association (GWA) mapping to uncover genetic polymorphisms mediating damage from foraging insects (two populations of Scaptomyza flava) across a mixture of Arabidopsis thaliana genotypes in experimental enclosures. The effect of chemical defenses (glucosinolates) on herbivory depended on herbivore genotype. Unlike many studies that minimize the effects of host choice behavior, we also found a large effect of plant size on herbivory—likely through its effect on plant apparency—that was independent of herbivore genotype. These herbivory-associated loci are polymorphic at fine spatial scales, and thus have potential to shape variation in herbivory within natural populations. We also show that the polymorphism with the largest effect on herbivory underlies adaptive latitudinal variation in Arabidopsis plant size across Europe. Overall, our results provide genetic support for ecological observations that variation in both chemical defenses and non-canonical defense traits (e.g., plant size and phenology) jointly shapes plant-herbivore interactions.