The specific involvement of coat protein in tobacco mosaic virus cross protection

Transgenic Nicotiana debneyii expressing viral coat protein are resistant to potato virus S infection

“…It has been postulated that one of the underlying mechanisms of cross-protection is that the presence of coat protein from the first virus acts to inhibit the uncoating of the second challenge virus or that it encapsidates the RNA of the challenging strain thereby preventing its replication. Although results with viroids (Niblett et al, 1978) and coat profein-deficient mutants of TMV (Sarkar & Smitamana, 1981) argue against this mechanism, other experiments demonstrating that naked CMV RNA or TMV RNA, or TMV RNA trans-encapsidated in brome mosaic virus coat protein effectively escaped the protection afforded by previous infection with a mild strain of the relevant virus (Dodds et al, 1985;Sherwood & Fulton, 1982), indicate that inhibition of virus uncoating plays some role in cross-protection. The extent to which classical cross-protection and the coat protein-mediated resistance in transgenic plants are related biological phenomena remains to be determined.…”

Effects of dicer-like endoribonucleases 2 and 4 on infection of Arabidopsis thaliana by cucumber mosaic virus and a mutant virus lacking the 2b counter-defence protein gene

“…Despite many years of study since its discovery by McKinney (1929), cross-protection is still poorly understood mechanistically (Ziebell, 2008). In certain instances, successful cross-protection between viral strains involves the coat protein, presumably where the presence of the coat protein of the protective strain inhibits the uncoating of challenge-strain virions (Culver, 1996;de Zoeten & Fulton, 1975;Koo et al, 2004;Lu et al, 1998;Sherwood, 1987;Sherwood & Fulton, 1982). However, not all instances of cross-protection can be explained this way (Gerber & Sarkar, 1989;Zaitlin, 1976).…”

Attenuated plant viruses: preventing virus diseases and understanding the molecular mechanism

“…In the former, the CP of a protecting virus present in cells may inhibit the uncoating step of an incoming virus. This case was first reported by Sherwood and Fulton (1982) who showed difficulty of infection by TMV in the yellow region of leaves with mosaic symptoms. Abel et al (1986) showed delayed expression of symptoms after inoculation with TMV in CP-expressing transgenic tobacco.…”