Molecular study of viruses from LN33 hybrid showing symptoms of corky bark disease
Goszczynski, D E
ARC Plant Protection Research Institute
Jooste, A E C
Corky bark is one of the four graft transmissible grapevine diseases of rugose wood complex. The disease is highly detrimental to some grapevine cultivars but in others it remains latent. Although grapevine virus B is believed to be the cause of this disease, there is no 100% association of the virus with corky bark. There are reports that corky bark can be induced in the absence of grapevine virus B, which suggests that this disease can be induced by different aetiological agents. Study of corky bark is complicated by the fact that corky bark-affected grapevines usually contain a mixture of different viruses. Prof. Martelli’s team (Bari, Italy), which is the leader in the study of grapevine virus B, states that “… GVB is an agent of corky bark, even though, perhaps, not the only one” (Minafra, 2000, 13th ICVG Meeting, Australia).
Molecular techniques adapted to the analysis of small amounts of dsRNA from virus-infected plants are the methods of choice for analysis of viruses from corky bark-affected grapevines. The perfection of these techniques may lead to the identification of known viruses, that differ from typical ones and the discovery of unknown viruses associated with the disease. A classical example of such an approach is the recent discovery of two new viruses in grapevine cv. Red Globe by the team of Dr. Rowhani (University of California, Davis, United States).
Detailed molecular analysis of dsRNA isolated from the LN33 hybrid showing symptoms of corky bark will be performed. The work will focus on plants originating from woody indexing of Richter 99 plants, which were recently shown to be positive for corky bark, but negative for leafroll, SG, Shiraz dieback and fleck diseases.
Goszczynski, D E and Jooste, A E C. 2002. Molecular heterogeneity of virus associated with leafroll, corky bark and Shiraz diseases of grapevines. Presentation at the Winetech Grapevine Virus Workshop. 6 May, Simondium, South Africa.
Goszczynski, D E and Jooste, A E C. 2003. LN33 plants infected with grapevine virus B do not always express symptoms of corky bark disease. Presented at the Winetech Grapevine Workshop. 5 May, ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa
Goszczynski, D E and Jooste, A E C. 2004. Is a grapevine virus B isolate, which does not induce corky bark disease in LN33, able to protect grapevines from severe pathogenic virus? Presentation at the Winetech Grapevine Workshop. 11 May, ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa
Goszczynski, D E and Jooste, A E C. 2005. Aetiology of corky bark disease – molecular and biological variability of grapevine virus B (GVB). Presentation at the Winetech Grapevine Workshop. 10 May, Stellenbosch, South Africa