RRC ID 31984
著者 Gloss AD, Vassão DG, Hailey AL, Nelson Dittrich AC, Schramm K, Reichelt M, Rast TJ, Weichsel A, Cravens MG, Gershenzon J, Montfort WR, Whiteman NK.
タイトル Evolution in an ancient detoxification pathway is coupled with a transition to herbivory in the drosophilidae.
ジャーナル Mol Biol Evol
Abstract Chemically defended plant tissues present formidable barriers to herbivores. Although mechanisms to resist plant defenses have been identified in ancient herbivorous lineages, adaptations to overcome plant defenses during transitions to herbivory remain relatively unexplored. The fly genus Scaptomyza is nested within the genus Drosophila and includes species that feed on the living tissue of mustard plants (Brassicaceae), yet this lineage is derived from microbe-feeding ancestors. We found that mustard-feeding Scaptomyza species and microbe-feeding Drosophila melanogaster detoxify mustard oils, the primary chemical defenses in the Brassicaceae, using the widely conserved mercapturic acid pathway. This detoxification strategy differs from other specialist herbivores of mustard plants, which possess derived mechanisms to obviate mustard oil formation. To investigate whether mustard feeding is coupled with evolution in the mercapturic acid pathway, we profiled functional and molecular evolutionary changes in the enzyme glutathione S-transferase D1 (GSTD1), which catalyzes the first step of the mercapturic acid pathway and is induced by mustard defense products in Scaptomyza. GSTD1 acquired elevated activity against mustard oils in one mustard-feeding Scaptomyza species in which GstD1 was duplicated. Structural analysis and mutagenesis revealed that substitutions at conserved residues within and near the substrate-binding cleft account for most of this increase in activity against mustard oils. Functional evolution of GSTD1 was coupled with signatures of episodic positive selection in GstD1 after the evolution of herbivory. Overall, we found that preexisting functions of generalized detoxification systems, and their refinement by natural selection, could play a central role in the evolution of herbivory.
巻・号 31(9)
ページ 2441-56
公開日 2014-9-1
DOI 10.1093/molbev/msu201
PII msu201
PMID 24974374
PMC PMC4137718
MeSH Acetylcysteine / metabolism* Animals Drosophilidae / classification Drosophilidae / genetics Drosophilidae / physiology* Evolution, Molecular Gene Duplication Glutathione Transferase / genetics* Glutathione Transferase / metabolism Herbivory / genetics Insect Proteins / genetics* Insect Proteins / metabolism Mustard Plant / chemistry Mustard Plant / metabolism* Mutation Phylogeny Plant Oils / metabolism* Selection, Genetic Signal Transduction
IF 11.062
引用数 43
WOS 分野 EVOLUTIONARY BIOLOGY BIOCHEMISTRY & MOLECULAR BIOLOGY GENETICS & HEREDITY
リソース情報
ショウジョウバエ 10045R-4