Impact of loss‐of‐function of FATTY ACID DESATURASE 7 in Arabidopsis thaliana on the green peach aphid, Myzus persicae, and the cabbage aphid, Brevicoryne brassicae

Abstract

AbstractThe FATTY ACID DESATURASE 7 (FAD7) enzyme is widely conserved across many groups of plants and influences resistance to multiple stresses, including aphid infestation. In the model plant Arabidopsis thaliana (L.) Heynh. (Brassicaceae), a loss‐of‐function mutation in the FAD7 gene decreases population growth of a generalist herbivore, the green peach aphid (GPA), Myzus persicae (Sulzer) (Hemiptera: Aphididae). This study used multiple bioassay designs to further characterize the effects of a fad7 mutant on the GPA, and also to determine whether fad7 impacts a specialist herbivore, the cabbage aphid (CA), Brevicoryne brassicae L. (Hemiptera: Aphididae). In choice assays, when presented with wild‐type A. thaliana (Col‐0) or fad7, neither GPA nor CA showed a preference between genotypes within 48 h. In no‐choice assays the fad7 mutation decreased the overall population growth of GPA, with significant differences in juvenile production occurring as early as 48 h after infestation. In contrast, CA showed comparable population growth on fad7 and Col‐0 at all time points, from 24 to 144 h (6 days). No‐choice assays also demonstrated that the fad7 mutation increased GPA development time and reduced fecundity but did not influence the mortality rates of adults or juveniles, or the weight of newly emerged adults reared on fad7. These results indicate that aphid resistance in the fad7 mutant is species‐specific, and that it impacts the population growth of GPA solely through antibiosis, decreasing adult fecundity and increasing juvenile development time.