Grapevine virus sampling kit
As with animals, grapes and other crops can be sick. Microorganisms such as the virus, bacterium, fungi, and others can be pathogens for crops. Grape Pathology lab at AHS Jr. AREC has been working on grapevine viruses and documented a total of ten viruses in our area, including five viruses new to the Commonwealth. We also identified four vector insect species that can spread the viruses, and developed management strategies against these vectors to manage grapevine viruses.
After sampling more than 700 grapevines in the Commonwealth, we found that 90% of 101 surveyed-vineyards had at least one grapevine infected with one of the ten grapevine viruses. Among these, grapevine leafroll-associated viruses and grapevine red blotch virus are considered significant because they can cause a substantial reduction in sugar and color expression (i.e., anthocyanin production) in grape berries; thus, crops from the infected vines are not ideal for wine production.
One of the challenges of working with viruses is that we cannot see them easily, even with a good microscope. Moreover, symptom development can be very variable, and often different viruses can cause very similar symptoms. Thus, we need to identify them using molecular tools (e.g., Polymerase Chain Reaction, or PCR) to detect specific nucleic acid information (DNA or RNA) that matches the profile of the target virus. Another potential challenge is storage. Often time, we need to keep tissue samples in a refrigerator because the quality of the sample can degrade quickly.
While we work on these economically important pathogens, we have developed a grapevine virus sampling tool that can help us and also other scientists. This kit uses a nitrocellulose membrane and a specific extraction buffer to trap viruses in grape petiole sap in the membrane. Once the sample is processed, the method is so robust that it can store the virus DNA and RNA without the need for refrigeration for over a year. The kit is straightforward to use so that growers can process the sample and send the finished membrane to our lab for diagnostic, rather than shipping live plant tissues via an overnight shipping service. We can also use this kit to sample viruses in remote areas or underdeveloped countries where access to cold storage may be limited.
We are currently collaborating with Virginia Tech’s Plant Clinic to refine this kit further, and to make grapevine virus testing available at the clinic. If you are interested in how this kit works, the link below is a Youtube video showing how the samples can be processed.