Non-transmissibility of Pepper whitefly borne vein yellows virus (PeWBVYV) by the Mediterranean species of Bemisia tabaci and identification of a candidate insect receptor protein for poleroviruses

Abstract

Recent reports of transmission of poleroviruses by whiteflies is indicative of evolution of new virus-vector relationships. Pepper whitefly-borne vein yellows virus (PeWBVYV), was the first report of a polerovirus infecting pepper in Israel which was transmitted by whiteflies (MEAM1) and not aphids. This study reports the inability of the Mediterranean species (MED, Q biotype) of B. tabaci to transmit PeWBVYV. However we show that non-transmission of PeWBVYV by MED is not due to the lack of interaction with the GroEL protein of the Hamiltonella symbiont. Although not transmitted by MED, PeWBVYV was detected in its hemolymph, indicating its translocation across the MED midgut barrier. The aphid transmitted Pepper vein yellows virus 2 (PeVYV-2) was also detected in the hemolymph of MEAM1 whiteflies but PeWBVYV could not be detected in the aphid hemolymph. Interestingly, relative amounts of PeWBVYV in the hemolymph of the, MED was much lower than in hemolymph of MEAM1 whiteflies. We also identified a candidate receptor protein, complement component 1Q sub-complement binding protein (C1QBP) which interacts with the capsid proteins of PeWBVYV and PeVYV-2 but not with the whitefly transmitted Tomato yellow leaf curl virus by a yeast two-hybrid approach using the minor capsid protein (RTD) as bait to screen for interacting proteins against the whitefly cDNA library. C1QBP, is a known receptor of bacterial and viral pathogens but this is the first report of its interaction with a plant virus.