Aphid transmission of beet western yellows luteovirus requires the minor capsid read-through protein P74.

Abstract

Beet western yellows luteovirus is obligately transmitted by the aphid Myzus persicae in a circulative, non‐propagative fashion. Virus movement across the epithelial cells of the digestive tube into the hemocoel and from the hemocoel into the accessory salivary glands is believed to occur by receptor‐mediated endocytosis and exocytosis. Virions contain two types of protein; the major 22 kDa capsid protein and the minor read‐through protein, P74, which is composed of the major capsid protein fused by translational read‐through to a long C‐terminal extension called the read‐through domain. Beet western yellows virus carrying various mutations in the read‐through domain was tested for its ability to be transmitted to test plants by aphids fed on agro‐infected plants and semi‐purified or purified virus preparations. The results establish that the read‐through domain carries determinants that are essential for aphid transmission. The findings also reveal that the read‐through domain is important for accumulation of the virus in agro‐infected plants.

The Comparison of Antibodies Raised Against PLRV with Two Different Approaches - Viral Particles Purification and Recombinant Production of CP

“…This result are in agreement with Brault et al [38]; Filichkin et al [39]; Jolly and Mayo, [40]; Wang et al [41] found within the read through protein (RTD) there is a highly conserved N-terminal region and a variable C-terminal region. The full length RTP can be detected readily in infected tissue, but in purified virus preparations a significant portion of the C-terminus of the RTD is proteolytically processed yielding a 51-58 kDa RTP.…”

P0 proteins of European beet-infecting poleroviruses display variable RNA silencing suppression activity

“…P1 and P2 are required for virus replication (Mayo & Ziegler-Graff, 1996). ORF3 encodes the major coat protein (CP) involved in particle assembly and aphid transmission (Brault et al, 1995;Stevens et al, 2005). The product of ORF4 is thought to be a movement protein.…”

“…The product of ORF4 is thought to be a movement protein. P5 is expressed together with P3 as a fusion protein, the readthrough protein, whose Nterminal region contains important domains for aphid transmission and virus accumulation in plants (Brault et al, 1995;Bruyère et al, 1997).…”

Expression and suppression of circulative aphid transmission in pea enation mosaic virus.

“…The virions of both genera possess two structural proteins ; a dominant coat protein of around 21-23 kDa with lesser amounts of a 50-74 kDa protein. Studies in luteoviruses have demonstrated that the large subunits are composed of the coat protein and a protein encoded immediately downstream of the coat protein ORF (Bahner et al, 1990 ;Vincent et al, 1991 ;Tacke et al, 1990 ;Dinesh-Kumar et al, 1992 ;Reutenauer et al, 1993 ;Cheng et al, 1994 ;Filichkin et al, 1994 ;Brault et al, 1995 ;Wang et al, 1995). Serological studies in PEMV have likewise demonstrated the presence of coat protein-specific epitopes in the larger PEMV subunit, suggesting that it is also in part composed of the coat and a supplementary protein (Gabriel, 1983).…”

“…Recent studies of natural variants of potato leafroll virus differentiated on their relative efficiency of aphid transmission demonstrated that regulation of this phenotype could be mapped to specific regions in the C terminus of the readthrough protein (Jolly & Mayo, 1994), although serological studies have also implicated the coat protein as containing determinants critical to the virus-vector interaction (van den Heuvel et al, 1993). Furthermore, mutational analyses of the beet western yellows virus (BWYV) genome (Brault et al, 1995) and that of barley yellow dwarf virus (Chay et al, 1996) have also demonstrated that changes within the readthrough domain were sufficient to interfere with or abolish aphid transmissibility. Thus, it has been suggested that these minor structural components of the PEMV and luteovirus virions represent proteins that are involved in aphid transmission.…”