|Martin, Robert - Bob|
Submitted to: Virus and Viruslike Diseases of Pome and Stone Fruit
Publication Type: Book / Chapter
Publication Acceptance Date: 10/13/2009
Publication Date: 7/26/2011
Citation: Hadidi, A.F., Olmos, A., Pasquini, G., Barba, M., Martin, R.R., Shamloul, A. 2011. Double-stranded RNAs and their use for characterization of recalcitrant viruses. In: Hadidi, A., Barba, M., Candresse, T., and Jelkmann, W., editors. Virus and Viruslike Diseases of Pome and Stone Fruit. St. Paul, MN, APS Press. 323-326. Interpretive Summary:
Technical Abstract: The presence of high molecular weight, virus-specific, double-stranded RNAs (dsRNAs) in virus-infected plants are probably formed during virus replication and consists of full-length and subgenomic RNAs of single-stranded RNA viruses or genomes of dsRNA viruses. The sizes and patterns of these virus-specific dsRNAs after separation on gels can be useful in virus characterization. The usefulness of dsRNAs from virus-infected plants is based on the premise that healthy plants, not infected with a virus, do not contain dsRNAs. The size of the genomic dsRNAs and the absence or presence of subgenomic dsRNAs provide useful information on the type of virus(es) that may be infecting a plant. While the presence of dsRNAs in plant extracts is a good indication of virus infection, it must be taken into consideration that viruses of fungal or bacterial pathogens, endophytes or saprophytes, as well as mites or insects could be the source of the dsRNA. In the case of many viruses of pome and stone fruit crops as well as many other woody hosts, dsRNA has long been the only laboratory based means of detecting viruses in infected plants. These viruses often are not transmitted mechanically to herbaceous hosts and in most cases it has not been possible to purify these viruses directly from the infected woody plants. The method described by Morris and Dodds can be used to extract dsRNA from many plant species. However, the quality of dsRNA templates is influenced greatly by the host plant and tissues from which they are extracted. Many plants contain compounds such as glycosides, polyphenols, and polysaccharides that co-purify with nucleic acids and can interfere with electrophoretic mobility and inhibit the process of cloning and sequencing from dsRNA templates. Several strategies have been developed to overcome the inhibitors found in woody hosts. Currently, dsRNA templates are the most easily obtained material that can be used to obtain sequence information and subsequently to develop diagnostic tests for viruses of woody hosts.