Aphids can host several secondary symbionts (SS) in addition to the primary endosymbiontBuchnera aphidicola. These SS have been previously shown to alter various aphid phenotypes, including body color, heat resistance, or resistance to pathogens or parasites. Having characterized the pea aphid hemocytes, and thanks to the availability of lines harboring each SS separately in the same genetic background, we were able to demonstrate that i) plasmatocytes and granulocytes can phagocyte all primary and secondary symbionts but some of these SS seem able to survive inside hemocytes, ii) that the presence of some SS alters the number of these hemocytes, iii) that this effect can be symbiont-strain dependant. Altogether, we could demonstrate a strong interaction between aphid symbionts and immune cells, depending upon the symbiont, highlighting the link between immunity and symbiosis.
- Schmitz A, Anselme C, Ravallec M, Rebuf C, Simon JC, Gatti JL, Poirié M (2012) The cellular immune response of the pea aphid to foreign intrusion and symbiotic challenge.PLoS One7, e42114