The Fate of the Transport Protein of Tobacco Mosaic Virus in Systemic and Hypersensitive Tobacco Hosts

Abstract

SUMMARYThe transport protein of tobacco mosaic virus (TMV) (Mr 30 000, 30K non-structural protein) was detected on Western blots, using an antiserum to a synthetic C-terminal nonapeptide. Accumulation of this protein in subcellular fractions of inoculated leaves was measured during TMV infection of Nicotiana tabacum cv. Samsun and cv. Samsun NN. In cv. Samsun, a systemic host, the 30K protein appeared transiently in a crude membrane fraction but accumulated more stably in cell walls. In cv. Samsun NN, which is a hypersensitive host giving only localized infection, the early accumulation (up to 40 h; before any necrosis was visible) was the same as in cv. Samsun. However, as soon as necrosis was visible, the amount of 30K detected in the cell wall fraction decreased sharply and coat protein synthesis stopped. This drop in the amount of 30K protein is most easily interpreted as a side-effect of the hypersensitive reaction and may explain why TMV infection becomes localized in leaves of cv. Samsun NN.

A Spontaneous Red Clover Necrotic Mosaic Virus Mutant with a Truncated Movement Protein

“…A host hypersensitive response may prevent systemic infection by inducing resistance, blocking further cell-to-cell movement (Moser et al, 1988) and preventing the virus from reaching the vascular system. Evidence has recently been obtained to show that some RCNMV isolates induce a hypersensitive response, as evidenced by cell necrosis, the production of pathgenesis-related proteins of the PR1 family (van Loon, 1985) and induced resistance (S. J. Miller, unpublished results).…”

Detection of the movement protein of red clover necrotic mosaic virus in a cell wall fraction from infected Nicotiana clevelandii plants

“…Immunocytological studies have shown that the movement protein of tobacco mosaic virus (TMV) is localized in the plasmodesmata, both in infected plants and in uninfected transgenic plants expressing the movement protein from a chromosomally inserted gene (Tomenius et al, 1987;Atkins et al, 1991), and that the protein is found in a cell wall-enriched fraction after subcellular fractionation of tissue from infected plants (Moser et al, 1988;Lehto et al, 1990). Putative movement proteins of a number of other viruses, e.g.…”

Complete nucleotide sequences of two soybean mosaic virus strains differentiated by response of soybean containing the Rsv resistance gene

“…A single Mr 30 000 (30K) protein encoded by the tobacco mosaic virus (TMV) genome has been identified which potentiates cell-to-cell movement of TMV in tobacco plants (Deom et al, 1987;Meshi et al, 1987). It has been speculated that the 30K protein is either not expressed properly or is unable to act on cells in plants which do not support systemic movement of TMV (Moser et al, 1988;Taliansky et al, 1982).…”