Convergently Evolved Toxic Secondary Metabolites in Plants Drive the Parallel Molecular Evolution of Insect Resistance
| Autor: | Alexander Donath, Michael von Tschirnhaus, Georg Petschenka, Susanne Dobler, Vera Wagschal |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Insecta media_common.quotation_subject Insect Biology Evolution Molecular 03 medical and health sciences Phylogenetics Molecular evolution Convergent evolution Gene Duplication Gene duplication Botany medicine Animals Gene Ecology Evolution Behavior and Systematics Cardiac glycoside media_common Genetics Natural selection fungi Plants Cardenolides 030104 developmental biology Sodium-Potassium-Exchanging ATPase medicine.drug |
| Zdroj: | The American naturalist. 190(S1) |
| ISSN: | 1537-5323 |
| Popis: | Natural selection imposed by natural toxins has led to striking levels of convergent evolution at the molecular level. Cardiac glycosides represent a group of plant toxins that block the Na,K-ATPase, a vital membrane protein in animals. Several herbivorous insects have convergently evolved resistant Na,K-ATPases, and in some species, convergent gene duplications have also arisen, likely to cope with pleiotropic costs of resistance. To understand the genetic basis and predictability of these adaptations, we studied five independent lineages of leaf-mining flies (Diptera: Agromyzidae). These flies have colonized host plants in four botanical families that convergently evolved cardiac glycosides of two structural types: cardenolides and bufadienolides. We compared each of six fly species feeding on such plants to a phylogenetically related but nonadapted species. Irrespective of the type of cardiac glycoside in the host plant, five out of six exposed species displayed substitutions in the cardiac glycoside-binding site of the Na,K-ATPase that were previously described in other insect orders; in only one species was the gene duplicated. In vitro assays of nervous tissue extractions confirmed that the substitutions lead to increased resistance of the Na,K-ATPase. Our results demonstrate that target site insensitivity of Na,K-ATPase is a common response to dietary cardiac glycosides leading to highly predictable amino acid changes; nonetheless, convergent evolution of gene duplication for this multifunctional enzyme appears more constrained. |
| Databáze: | OpenAIRE |
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