Résumé
Aphids are among the most impactful agricultural pests, not only causing direct damage to crops but also transmitting hundreds of plant viruses, resulting in substantial global yield losses. The majority of aphid-borne viruses are transmitted in a non-circulative manner, and are transiently retained on specific receptors on the surface of the cuticle of aphid stylets. The study of stylet cuticle and its associated cuticular proteins remains a persistent challenge, as the candidate receptors are resistant to conventional protein-protein interaction approaches. To identify virus receptors and explore the binding properties of aphid stylets, our team has developed an integrated approach combining multi-omics, advanced microscopy and 3D imaging techniques and gene function validation through RNAi or CRISPR-Cas9 targeted mutagenesis in aphids. We have shown that cuticular proteins are not uniformly distributed in the stylets, conferring a local functionalization of cuticular micro-territories such as the acrostyle, a discrete structure at the apex of maxillary stylets capable of binding salivary effectors. Remarkably, certain plant viruses have evolved to bind this structure to facilitate their transmission from plant to plant. Among the identified acrostyle proteins, stylins from the CPR RR-1 family feature exposed domains at the virus-vector interface. Stylin-01 was recently confirmed as a key factor in the transmission of cauliflower mosaic virus by aphids, representing the first, but not the only, receptor identified on the cuticle surface. Ongoing investigations aim to elucidate the role of stylins in the transmission of other plant viruses, with particular emphasis on turnip mosaic virus (Potyvirus).