Texas A&M AgriLife Research scientists have generated the first infectious clone of tomato spotted wilt virus in the United States, a laboratory breakthrough that gives plant breeders a faster way to test peppers, tomatoes and other crops for resistance to a disease that costs growers millions of dollars annually.
The clone lets researchers introduce the virus into plants under controlled conditions and measure how each variety responds, rather than waiting for thrips — the tiny insects that spread the pathogen — to deliver it unevenly across a field. That control is what makes the tool valuable: resistance screening that once took multiple growing seasons can now be run on a shorter, more predictable timetable.
Tomato spotted wilt virus ranks among the most damaging plant pathogens worldwide, infecting more than 1,000 plant species, including peppers, tomatoes, peanuts, lettuce and ornamental flowers. In peppers, infection stunts the plant and scars or discolors the fruit, cutting marketable yield. The virus is spread almost exclusively by thrips, which acquire it while feeding and carry it for life, making outbreaks difficult to predict and expensive to spray against.
Because the virus is transmitted biologically rather than through seed or soil alone, fields cannot be protected with a single chemical treatment. Breeders have relied on naturally occurring resistance genes, but identifying which plant lines actually hold up requires exposing them to the virus — a step the new clone makes faster and more consistent.
Texas A&M AgriLife, part of the Texas A&M University System, conducts crop research across more than a dozen stations in the state. Its vegetable breeding programs serve growers in Texas and the surrounding region, where pepper production is concentrated in the Rio Grande Valley and the High Plains.
An infectious clone is a laboratory-built copy of the virus's genetic material that can be introduced directly into a plant, bypassing the insect vector. Researchers use it to compare how different virus strains behave and to confirm whether a plant's resistance holds against each one.
The advance matters beyond the laboratory because pepper and tomato growers face limited options once a field is infected. There is no cure for a plant already carrying the virus. Resistant varieties are the primary defense, and every year a new variety spends in development is a year growers absorb losses.
Details of the clone and its development were reported by Texas A&M AgriLife Research. The work is expected to support breeding programs evaluating pepper and other susceptible crops for durable resistance.
