title: Comparative analysis of quantitative trait loci controlling glucosinolates, myrosinase and insect resistance in Arabidopsis thaliana.
abstract: Evolutionary interactions among insect herbivores and plant chemical defenses have generated systems where plant compounds have opposing fitness consequences for host plants, depending on attack by various insect herbivores. This interplay complicates understanding of fitness costs and benefits of plant chemical defenses. We are studying the role of the glucosinolate-myrosinase chemical defense system in protecting Arabidopsis thaliana from specialist and generalist insect herbivory. We used two Arabidopsis recombinant inbred populations in which we had previously mapped QTL controlling variation in the glucosinolate-myrosinase system. In this study we mapped QTL controlling resistance to specialist (Plutella xylostella) and generalist (Trichoplusia ni) herbivores. We identified a number of QTL that are specific to one herbivore or the other, as well as a single QTL that controls resistance to both insects. Comparison of QTL for herbivory, glucosinolates, and myrosinase showed that T. ni herbivory is strongly deterred by higher glucosinolate levels, faster breakdown rates, and specific chemical structures. In contrast, P. xylostella herbivory is uncorrelated with variation in the glucosinolate-myrosinase system. This agrees with evolutionary theory stating that specialist insects may overcome host plant chemical defenses, whereas generalists will be sensitive to these same defenses.
authors.affiliation: Department of Genetics and Evolution, Max-Planck Institute of Chemical Ecology, 07745 Jena, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kliebenstein
authors.forename: Deana
authors.initials: D
authors.lastname: Pedersen
authors.forename: Bridget
authors.initials: B
authors.lastname: Barker
authors.forename: Thomas
authors.initials: T
authors.lastname: Mitchell-Olds
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics* / Q000469:parasitology; D029681:Arabidopsis Proteins; D004843:Epistasis, Genetic; D014644:Genetic Variation; D005961:Glucosinolates / Q000235:genetics* / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics*; D007915:Lepidoptera / Q000472:pathogenicity; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D019655:Quantitative Trait, Heritable; D011956:Receptors, Cell Surface / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D005961:Glucosinolates; D011956:Receptors, Cell Surface; C457763:ER protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D006026:Glycoside Hydrolases; C022739:thioglucosidase