The United States produces 4% of the annual global onion supply with 125,000 acres planted across the country. This accounts for billions of dollars’ worth of produce with Washington and Idaho/Oregon producing the highest numbers of onions. Tospoviruses are enveloped viruses that infect plants, leading to tissue necrosis. The Iris yellow spot tospovirus (IYSV) is one variety of tospovirus and is the most common virus found in food crops in the United States, particularly in onion supplies. IYSV affects onion fields throughout the country but has the greatest impact in Washington, Oregon and California where a large portion of the country’s onion supplies originate. The virus causes multimillion dollar crop losses worldwide and it is often difficult to make diagnoses based on symptoms alone.
The Washington State University is home to a strong agricultural science division who have been investigating ways to minimise the spread of IYSV and in some places to eliminate it completely. One team, led by postdoctoral research associate Diwaker Tripathi, are using PCR analysis to detect and treat infected crops in the Washington area.
Conducting PCR analysis on onion crops requires fields to be identified as ‘potentially affected’ in the first place through visual clues such as lesions on leaves. From there, samples are taken for further analysis to determine whether the visible symptoms are false positives or if the crops are actually infected. To do this PCR analysis conducted in the central lab determines whether or not the virus is present. Positive results require immediate remedial action as IYSV is a fast spreading virus, wiping out entire crops in the couple of days. Removing infected plants is the best way to ensure the least impact possible. To do this however, the area of infection is determined through additional PCR analysis. This means samples are tracked back and forward from the lab over some days to ensure the total infected area is identified. With a fast moving target, this can be a very difficult task.
Tripathi has recognised an opportunity in mobile molecular testing to increase the effectiveness of IYSV identification and removal. Being able to test samples in near real time would allow infection areas to be quickly identified and infected crops to be removed immediately. This would stop virus spread then and there, rather than allowing up to a week during sample testing and mapping for the virus to continue to spread.
By reducing the time taken to test and identify infected crops, hundreds of thousands of dollars’ worth of onion crops could be saved throughout the United States. Current lengthy lab-based methods potentially permit whole crops to become infected leading to them being destroyed. The use of mobile molecular testing would prevent this destruction by rapidly containing virus spread. This benefits both the growers as well as the hundreds of importers and exporters of onions.
Ubiquitome is running a grants program for research groups who would benefit from a mobile qPCR device. Diwaker Tripathi has been chosen as one of the finalists. To find out more about the program and view the other finalists, visit the website here.