Potato Virus Y Transmission Research Articles

Effects of the repellent polygodial on stylet penetration behaviour and non‐persistent transmission of plant viruses by aphids

Abstract: Behavioural effects of the plant‐derived repellent polygodial were investigated by video recording aphids during access to potato virus Y (PVY) or cucumber mosaic virus (CMV) infected tobacco leaf material. Stylet penetration of floating leaf discs, assessed using antennal and body movements as behavioural markers, was significantly delayed by polygodial treatment of the leaf surface. This delay may help account for a previously reported reduction of virus transmission caused by polygodial, although the majority (77%) of aphids on polygodial‐treated leaf areas penetrated within the first minute, compared with 100% on solvent‐treated areas. Neither the duration of stylet penetrations, nor subsequent transmission of PVY or CMV, were affected by the presence of polygodial on virus‐infected plants. Electrical recording of stylet activities confirmed that aphid stylets punctured plant cell membranes, regardless of polygodial treatment of PVY‐infected plants.

Solanum viarum:Weed reservoir of plant viruses in Florida

Abstract Solanum viarum Dunal (tropical soda apple), an introduced and rapidly spreading weed, currently infests over 60 000 ha in Florida. Approximately 220 plants were sampled in seven stands of S. viarum in south‐west and west central Florida during 1992 and 1993 to determine the occurrence of nine viruses which can infect solanaceous crops. Virus detection utilized a double antibody sandwich‐enzyme linked immunosorbent assay, or a nucleic acid spot hybridization assay. The viruses detected included cucumber mosaic virus (CMV), potato leaf roll virus (PLRV), potato virus Y (PVY), tobacco etch virus (TEV), tomato mosaic virus (ToMV), and tomato mottle virus (TMoV). Transmission of PVY and ToMV from S. viarum produced a range of symptoms in pepper, tobacco, and tomato. Isolates of TEV from pepper, and PVY and TMoV from tomato were transmitted to S. viarum. Solanum viarum was also naturally infected in the field by Altemaria solani Sorauer and infested by Colorado potato beetles (Leptinotarsa decenlineata...

Comparative sequence of the helper component (HC) region of potato virus Y and a HC-defective strain, potato virus C

Potato virus C (PVC), a non-aphid transmissible strain of potato virus Y (PVY), was found to code for a protein (PVC-HC) which is similar in molecular weight and immunological reactivity to the helper component protein of PVY (PVY-HC). PVC-HC, however, was inactive with respect to its ability to effect aphid transmission of either PVC or PVY. The 5′-terminal 2.7-kb regions of PVC and PVY were sequenced. Within the HC region there was 92% nucleotide homology between the two strains; comparison of the derived amino acid sequences revealed 24 amino acid differences. Comparison of the PVC-HC sequence with that of five potyviruses revealed 2 amino acid changes which were specific to PVC-HC. These amino acids are prime targets for mutational analysis of HC activity.

Engineering resistance to mixed virus infection in a commercial potato cultivar: resistance to potato virus X and potato virus Y in transgenic Russet Burbank.

Potato virus X (PVX) and potato virus Y (PVY) infection in potato may result in the loss of certification of seed potatoes and affect quality and yield of potatoes in commercial production. We transformed a major commercial cultivar of potato, Russet Burbank, with the coat protein genes of PVX and PVY. Transgenic plants that expressed both CP genes were resistant to infection by PVX and PVY by mechanical inoculation. One line was also resistant when PVY was inoculated with viruliferous green peach aphids. These experiments demonstrate that CP protection is effective against mixed infection by two different viruses and against mechanical and aphid transmission of PVY.

Further studies on the transmission of plant viruses by different forms of aphids

Various forms of four aphid species were tested as vectors of potato virus Y (PVY) and cabbage virus B (CVB). Oviparous females of Macrosiphum euphorbiae (Thom.) and Brevicoryne brassicae (L.) transmitted the viruses as efficiently as did apterous viviparous females. In addition, PVY was transmitted by oviparae of Aulacorthum solani (Kltb.), and by males of M. euphorbiae. A “vector form specificity” seemed to exist in the transmission of PVY by fall and spring forms of Aphis nasturtii Kltb. The virus was transmitted by migratory forms such as gynoparae, males, and fundatrigeniae which during part of their life cycle live on virus-susceptible hosts, but not by oviparae and fundatrices, which spend their entire life cycle on the winter host. Thus vector form specificity in the transmission of PVY seems to be related to the host range of the aphid form.