Résumé
Most plant viruses are transmitted by vectors, particularly by hemipteran insects. The interactions between plants, viruses and insect vectors are obviously highly sophisticated, but they remain only very fragmentarily understood. Indeed, while countless reports have focused on two way interactions between the couples plant-insect, plant-virus, and virus-insect, the studies actually addressing three ways interactions in this type of biological system remains extremely scarce. The impact of plant viralinfection on the insect behavior have sometimes been addressed, reporting for example increased insect attraction due to changes in leaf colors, in volatile emission, or in sap composition. Surprisingly enough, despite the fact that common defense pathways are induced in plants by viral infection and by insect attack, a possible impact of the insect colonization of the plants onto the viral infection cycle has never been addressed. We have recently demonstrated that Cauliflower mosaic virus (CaMV) is able to highjack the plant perception of aphid feeding, and to immediately react by producing transmission specific morphs within infected plant cells. Interestingly, we demonstrated that non-aphid stresses such as wounding, or exposure to CO2-saturated atmosphere is provoking the same CaMV reaction, correlatively enhancing the efficiency of vector-transmission. This discovery is opening a wide new horizon for research in this field, evaluating the possible range of viral reactions to the feeding of insect vectors, and the range of unrelated biotic or non-biotic stresses that can “falsely” provoke these viral reactions and increase transmission