Endophytic entomopathogenic fungi and host plant interactions: impact on phytovirus transmission by insect vector

Entomopathogenic fungi (EPF) are biological agents used to control crop pests. They infect their host insects transcutaneously, synthesize toxic secondary metabolites, multiply and colonize their host tissues leading to death. Currently, the mode of action by contact is the most widespread, but recent studies highlighted the successful way of inoculating endophytic strains in plants for systemic action. Therefore, endophytic EPF complete their life cycle in host plants tissues without symptom appearance. They interact then with plants pests and phytopathogenic agents. Our goal was to determine whether the presence of endophytic EPF in host plant tissues influenced the vector insect behavior with an impact on plant virus transmission. Previously, we have shown that the inoculation of two commercial strains of EPFs (Beauveria bassiana GHA from Botanigard® and Metarhizium acridum ARSEF 7486 from Green Muscle®) on tobacco (Nicotiana tabacum L.) have a negative influence on the Myzus persicae Sulzer life history. Here, we were looked at the transmission aspect of the Potato leaf roll virus (PLRV) on tobacco by M. pesicae. After a qualitative ELISA test on plants infested with virus-carrying insects, we found that a trend is emerging on inoculated B. bassiana plants with low PLRV transmission rate relative to the control. Interactions between plant – aphid – virus and entomopathogenic fungi are discussed in terms of optimal stragtegies to promote broad biological control and sustainable crop production.