Understanding the proteomic composition of the acrostyle through novel methods and the identification of cuticular proteins available for viral binding

BGPI : équipe 2The acrostyle is a distinct anatomical region present along the surface of the common duct at the distal tip of the maxillary stylets, after the fusing of the food and salivary canals. This structure is known to be conserved across multiple aphid species which vector plant viruses and is known to contain the receptor of at least one plant virus, Cauliflower mosaic virus(CaMV), and presumably other viruses (Uzest et al., 2007). This receptor is known to be a non-glycosylated protein embedded within the matrix of chitin fibers of the stylet. Additionally a motif present within many RR-2 family proteins was earlier identified in the acrostyle (Uzest et al., 2010). To better characterize the role of the acrostyle in the transmission of non-persistent viruses two novel tools were developed to examine its proteomic composition: a series of cuticular protein(CuP) specific antibodies from across the conserved RR-2 chitin binding consensus domain, and an array of peptides covering the diversity of Acyrthosiphon pisum RR-2 CuPs. Three regions of the RR-2 domain could be detected at the acrostyle at either the surface, or embedded in the chitin matrix. Hybridizations of viral proteins of non-persistent viruses to the peptide array also revealed peptides that specifically bound these non-persistent viruses. From these peptides two conserved motifs within RR-2 family proteins were identified that may have a role in non-persistent viral transmission. Together these results increase the knowledge of peptides within the RR2 CuPs present at the acrostyle and indicate regions which warrant further research