Stylin-1: a putative receptor of Cauliflower mosaic virus
Résumé
The receptor of Cauliflower mosaic virus (CaMV) has been shown previously (Uzest et al., 2009) to be a surface exposed cuticular protein (CuP) occurring at the tip of maxillary stylets along a discrete organ called the acrostyle. However, while thelocation has been determined, the identity of this receptor has not been identified despite a plethora of attempts. Additionallyit is presumed that the receptors of other non-persistent viruses, including the Potyvirsues and Cucumber mosaic virus arelocated at, or close to, the acrostyle, hence the great interest in this region and its involvement in plant-insect and virusinsectinteractions. Here we identify for the first time a CuP which is present at the surface of the acrostyle of Acyrthosiphonpisum, making it the first protein specifically identified within the stylets of aphids and for which we propose the name stylin-1. Additionally we determined that stylin-1 collocates with the P2 helper protein of CaMV at the surface of the acrostyle andis conserved within the stylets of several important vectors of non-persistent viruses including Aphis gossypii, Brevycorniaebrassicae and Myzus persicae. Competition/blocking of the acrostyle, by sequentially labelling stylets with the P2 helperprotein and stylin-1 antibody, were used to determine the interaction of the two on dissected stylets. In these experimentsP2 reduced significantly the amount of subsequent labelling of the stylin-1 antibody indicating competition for the samemolecule. Hence, we propose that stylin-1 may be the first receptor of a non-persistent virus found.