Conventional and novel approaches for managing "flavescence doree" in grapevine: knowledge gaps and future prospects

"Flavescence doree" (FD) is a grapevine quarantine disease associated with phytoplasmas and transmitted to healthy plants by insect vectors, mainly Scaphoideus titanus. Development of efficient methods for its control has been hampered by the lack of knowledge about phytoplasma biological properties, linked also to difficulties in its in vitro cultivation. Conventional management strategies rely mainly on the application of insecticide treatments, roguing of infected plants and production of phytoplasma-free propagation material. However, these strategies are costly and could have undesirable environmental impacts. Novel approaches are being investigated using transcriptomic and proteomic tools that can assist in identifying key regulators expressed by diseased, recovered and healthy plants. These studies allowed the identification of molecular profiles linked to the grapevine cultivar-diverse susceptibility that are of great interest for the development of FD less susceptible plants by breeding programmes. Other promising FD management strategies include the use of grapevine endophytic microorganisms with known biocontrol properties and endophytes living inside specialized insect cells, which can be potential candidates for FD vector control. Finally, the application of plant defence elicitors might be an interesting tool for FD containment, but more research is needed before it can be implemented. In this review, the methodologies used for detecting and confining FD diffusion are discussed, focusing mainly on conventional tools, current research perspectives and knowledge gaps.