Xylella fastidiosa - Insect Vector Interactions: Current and Potential Future Research Directions
Vectors play a major role in epidemiology of diseases caused by Xylella fastidiosa. Information on vector ecology, behavior and transmission sets the basis for identifying key species involved in pathogen spread and approaches to manage the diseases. The bacterium is non-circulative (foregut-borne), lacking latent period and transstadial transmission, but it is persistently-transmitted after acquisition by adults due to biofilm formation and propagation on the vector retention sites (e.g. the cuticular lining of the precibarium). The ability to sequence and transform X. fastidiosa, combined with advanced studies employing functional genomics, vector acquisition of cultured cells from artificial diets, microscopy and PCR-based assays, allowed the development of a model for bacterial adhesion and biofilm formation in the vector´s foregut. Host selection, electrical penetration graph (EPG) and acoustic communication studies have indicated vector behavioral aspects that could be manipulated to manage vector population and/or reduce pathogen transmission. Transmission efficiency is markedly influenced by X. fastidiosa populations in source plants (and maybe in the vectors), suggesting that approaches targeting bacterial growth may be useful to reduce transmission rates. Future research should translate fundamental knowledge of X. fastidiosa-vector-plant interactions into new ways to disrupt the transmission process and generate sustainable management strategies.