Grapevine Vitiviruses

The discovery, isolation, and characterization of grapevine vitiviruses have spanned the history of grapevine virology. After the description of the rugose wood disease complex in the early 1960's, increasing evidence accumulated to link some members of this group of viruses with that disease. Improved serological and molecular detection techniques, findings regarding the transmission of vitiviruses by mealybugs, and the analysis of the genetic variability of these viruses have provided insights into their relevance to the grapevine industry and the importance of their inclusion in certification programs for the production of clean propagation stocks. The difficulty in satisfying Koch's postulates (i.e., the demonstration of the actual role of these viruses in eliciting wood and bark alteration symptoms) is due to the inability to infect grapevine via inoculation with virus particles. The synthesis and use of infectious full-length genomic clones and reverse genetic analyses will allow infectivity and functional genomic experiments in a variety of grapevine germplasm, in which it will be possible to discern differential reactivity leading to symptom expression