Researchers uncover secrets of destructive plant virus

By Kate Wilhite, College of Agricultural, Human & Natural Resource Sciences

Pappu,-80PULLMAN, Wash. – A Washington State University professor and a colleague from Australia have deciphered the inner workings of one of the world’s most destructive crop viruses.

Tomato spotted wilt virus (TSWV) is a global pest estimated to cause more than $1 billion in crop losses each year. Like the other 25 known tospoviruses, TSWV is spread by thrips, tiny black-winged insects that feed on the sap of many food, fiber and feed plants including bean, lettuce, peanut, pepper, potato and tomato.

The strategy for reducing damage caused by TSWV is to grow virus-resistant crop varieties. However, viruses are notorious for overcoming resistance.

Scientists have known TSWV carries a gene that overcomes a plant’s defenses, but what part of the gene has remained a mystery until now.

After applying highly sophisticated total genome sequencing technologies and bioinformatics analysis, “the virus finally started giving away its secrets,” said project leader Hanu Pappu (

Pappu,-left,-and-Mitter-400Pappu, the Sam Smith Distinguished Professor of Plant Virology at WSU, collaborated with Neena Mitter, an associate professor at the University of Queensland in Brisbane and authority on silencing suppressors coded by plant viruses. The researchers identified the regions of the viral genome that are most vulnerable to interference and therefore can be manipulated into suppressing virus replication.

The collaborative effort began in 2011 when Mitter spent three months visiting Pappu’s lab.

Pappu has studied the tospovirus family for nearly two decades. His research focuses on understanding the biology and molecular biology of the thrips-tospovirus complex in order to develop effective and novel virus suppression strategies in both plant hosts and insect vectors.

The results of the research were recently published in the online journal PLOS ONE at



Hanu Pappu, WSU Department of Plant Pathology, 509-335-9541,

Kate Wilhite, WSU CAHNRS Marketing, News and Educational Communications, 509-335-8164,