Evolution of symbiosis in insects : mechanisms involved in associations between aphids and the gut-associated Serratia symbiotica bacterium
(2019) UK-France joint meeting on aphids — Location: Harpenden, UK (3.April.2019)
Files
No attached file found for this publication.
Details
- Authors
- Abstract
- Symbiotic microorganisms are widespread in nature and can play a major role in evolution. A key question in evolutionary ecology is how mutualistic associations are established and evolve. The aphid-Serratia symbiotica bacterium interaction provides a valuable model to study mechanisms behind this question. S. symbiotica is one of the most common symbionts among aphid populations and includes a wide variety of strains whose degree of interdependence on the host may vary considerably. S. symbiotica strains with free-living capacity have recently been isolated from aphids. By using these strains, we established artificial associations by simulating new bacterial acquisitions involved in aphid gut infections to decipher their infection processes, associated biological effects on their new hosts as well as the way they infect aphids and their transmission behaviour. Our study showed that the cultivable S. symbiotica colonized the aphid digestive tract following infection, after which the bacterium multiplied exponentially during aphid development. Our results further revealed that gut colonization by the bacteria induce a fitness cost. However, it appeared that they also offer an immediate protection against parasitoids that should probably in some conditions compensate the costs. Moreover, cultivable S. symbiotica seem to be extracellularly transmitted, partly through the honeydew and the plant sap. Indeed, we showed that the circulation of the cultivable S. symbiotica in aphids can be mediated by plants. We discovered that the cultivable S. symbiotica can be absorbed by plant roots and induce new bacterial infections in aphids feeding on these new infected plants. Furthermore, our results demonstrated that cultivable S. symbiotica can be horizontally transferred from infected to uninfected aphids sharing the same plant, providing first direct evidence that plants can mediate horizontal transmission of certain strains of this symbiont species. These findings provide new insights into the nature of symbiosis in aphids and highlight the importance of considering symbiotic associations in complex systems where microorganisms can circulate between different compartments.
- Affiliations
Citations
Pons-Guillouard, I., Renoz, F., Noël, C., & Hance, T. (2019). Evolution of symbiosis in insects : mechanisms involved in associations between aphids and the gut-associated Serratia symbiotica bacterium. UK-France joint meeting on aphids, Harpenden, UK. https://hdl.handle.net/2078.5/248056