MICOTI project: towards a fungal-based integrated pest management against Scaphoideus titanus

The leafhopper Scaphoideus titanus is the main vector of the EU quarantine pest "Candidatus Phytoplasma vitis", which is associated with the Flavescence dorée (FD) disease in grapevine. Due to the epidemic nature of this disease and the severity of the damage caused in vineyards, winegrowers are likely to respond with more intense insecticidal treatments. However, insecticides have a considerable economic impact on viticulture, as well as harmful consequences for human and animal health and for the biodiversity of the ecosystems. For this reason, recent European regulations insist on the urgency of minimizing the use of chemicals. As a significant step in this direction, the project aims at developing two complementary sustainable approaches for the biocontrol of FD. Both are based on insect-fungal interactions: one explores the potential application of naturally occurring entomopathogenic fungi (EPF) against the insect, whereas the other is based on the possibility of using RNA interference (RNAi) mechanisms against the yeast-like endosymbiont of S. titanus (StYLS), which is phylogenetically related to entomoparasitic Ophiocordyceps fungi. EPF strains will first be selected based on their pathogenicity through direct contact with S. titanus cuticle and, then, by their ability to spread and persist in the vegetative tissues of grapevine. The project will also assess whether EPF in the endophytic state can have detrimental effects on S. titanus by altering the plant metabolism. Through genomic and proteomic characterization of StYLS, the project will identify and silence the fungal genes involved in the metabolic pathways (e.g. biosynthesis of amino acids and vitamins) considered essential for the insect survival. In this way, MICOTI will explore for the first time the possibility to interfere with the gene expression of a fungal endosymbiont to perturb the fitness of its insect host.