Silencing of ATP Synthase β Impairs Egg Development in the Leafhopper Scaphoideus titanus, Vector of the Phytoplasma Associated with Grapevine Flavescence Dorée

Abstract

Scaphoideus titanus (Hemiptera: Cicadellidae) is the natural vector of Flavescence dorée phytoplasma, a quarantine pest of grapevine with severe impact on European viticulture. RNA interference (RNAi) machinery components are present in S. titanus transcriptome and injection of ATP synthase β dsRNAs into adults caused gene silencing, starting three days post injection (dpi) up to 20 dpi, leading to decrease cognate protein. Silencing of this gene in the closely related leafhopper Euscelidiusvariegatus previously showed female sterility and lack of mature eggs in ovaries. Here, alteration of developing egg morphology in S. titanus ovaries as well as overexpression of hexamerin transcript (amino acid storage protein) and cathepsin L protein (lysosome proteinase) were observed in dsATP-injected females. To evaluate RNAi-specificity, E.variegatus was used as dsRNA-receiving model-species. Different doses of two sets of dsRNA-constructs targeting distinct portions of ATP synthase β gene of both species induced silencing, lack of egg development, and female sterility in E. variegatus, indicating that off-target effects must be evaluated case by case. The effectiveness of RNAi in S. titanus provides a powerful tool for functional genomics of this non-model species and paves the way toward RNAi-based strategies to limit vector population, despite several technical and regulatory constraints that still need to be overcome to allow open field application.

Metatranscriptomic Assessment of the Microbial Community Associated With the Flavescence dorée Phytoplasma Insect Vector Scaphoideus titanus

“…The newly assembled S. titanus transcriptome, alongside the transcriptome of the other phytoplasma vector Euscelidius variegatus (Galetto et al, 2018 ), provides a valuable sequence resource for downstream applications, such as the implementation of strategies based on RNA interference (RNAi) for studying the insect gene function as well as for devising new biocontrol tactics against the insect vector (Ripamonti et al, 2022 ). Analogously, the analysis of the composition of S. titanus microbiome and a better understanding of the complex interactions within the holobiont could further contribute to the identification of novel targets for sustainable strategies to counteract the Flavescence dorée spread in Europe.…”

Grapevine Resistant Cultivars: A Story Review and the Importance on the Related Wine Consumption Inclination

“…Grapevine is also facing a number of other diseases which require chemical treatments, including esca, black rot, Flavescence doree, phytoplasmas, etc. [15][16][17][18]. This results in a challenging defensive chemical management.…”