Scientists Aim for Better Control of Tomato Spotted Wilt Virus

Texas A&M AgriLife Research scientists have received two grants from USDA and the National Science Foundation (NSF) to develop better control and understanding of tomato spotted wilt virus (TSWV), one of the top 10 most economically important plant viruses in the world.

Kiran Gadhave, Texas A&M Assistant Professor, will lead one grant and is a co-investigator on the other.

The most recent project and the one Gadhave is leading is funded by a three-year, $887,000 grant from the USDA’s Agricultural Marketing Service, which will pursue research applications to develop better control of the pathogen.

A related three-year, $993,002 grant from NSF and USDA’s National Institute of Food and Agriculture will focus on understanding the virus on a fundamental level.

Tomato Spotted Wilt Virus Specs

Tomato spotted wilt virus infects more than 1,000 plant species, including both specialty and staple food crops and weeds, causing an estimated $1 billion in crop losses worldwide each year.

Stunting, mosaic-like patterns on leaves, a lack of fruit, or rot-like spots on fruit are some of the symptoms of the disease in crops. Badly infected produce cannot be sold and is unpalatable. Studies show the virus continues to change, and new strains have been reported in at least 10 countries. “A single gene in tomatoes offers resistance against this virus,” Gadhave says. “But new virus strains have emerged, which our lab has reported, that have been breaking that resistance. So those virus-resistant tomato cultivars are not completely effective anymore.”

These “resistance-breaking” strains of the virus are of particular concern and will be a key focus of the new applied and basic research.

Another complication in combating the virus is its main insect vector, western flower thrips.

“The unique thing about this virus is that it can replicate in insect and plant hosts,” Gadhave says. “It’s a cross-kingdom virus.”

Applied Research

The applied USDA-AMS project aims to help vegetable growers through new crop cultivars, new detection methods, and updated, science-based management recommendations. The results and outcomes will also inform future research and education.

In addition, given the global agricultural significance and economic impact of the tomato spotted wilt virus, the project will also help educate the public about agriculture, Gadhave says.

Joining Gadhave on the USDA-AMS grant are several Texas A&M faculty members as well as collaborators from North Carolina State University the University of California, Davis.

The team will pursue six connected goals:

1. Surveillance of resistance-breaking virus strains in major tomato and pepper growing regions of the U.S.
2. With growers, estimate the economic losses due to the virus and calculate the cost-effectiveness of different management strategies.
3. Development of diagnostic tools to reliably and efficiently detect resistance-breaking virus variants.
4. Understanding the transmission biology of the resistance-breaking strains and identifying strategies to disrupt transmission.
5. Evaluating the impact of growing practices on disease transmission, including a comparison between high tunnels and open fields.
6. Developing new crop cultivars with strong resistance to resistance-breaking virus strains.

After the USDA-AMS work is completed, Gadhave says, growers should have a new, cutting-edge diagnostic tool, research-based recommendations for sustainable crop production, and, potentially, new cultivars.