Multi-approach comparative study of the two most prevalent genotypes of pea aphid Acyrthosiphon pisum (Hemiptera: Aphididae) in Chile.
The pea aphid, Acyrthosiphon pisum Harris, is able to colonize various habitats and form genetically distinct biotypes worldwide. In Chile, few genotypes are dominating in space and time and are qualified as "superclones". Here, we compared in the laboratory different biological features of the most common clones of A. pisum collected from pea (Ap1) and alfalfa (Ap2) fields, in order to gain some insight on their differential ability to colonize broad bean plants. We also studied their probing behavior, profiled their proteome and characterized their community of endosymbionts. We found that the Ap1 genotype performed better on Vicia faba and realized more salivation events in phloem than Ap2. In addition, Ap1 presented a higher prevalence of the endosymbiont Serratia symbiotica. Among the total of 40 proteins that were differentially expressed, 14 and 26 were upregulated in Ap1 and Ap2 genotypes, respectively. The symbionin from Buchnera aphidicola was found to be upregulated in Ap1. A field experiment showed that both genotypes were able to colonize wild legumes, with Ap1 reproducing better on Vicia nigricans than Ap2. However, Ap2 exhibited higher reproduction in the other three wild legumes, suggesting higher invasiveness capacity on wild plants. Variation in the ability to colonize, feeding behavior and the putative involvement of differentially regulated proteins between Ap1 and Ap2 are discussed in relation to their respective endosymbiotic composition, nutritional lifestyle and consequences on their "superclone" status.