Stewart Gray

Stewart Gray

Courtesy Professor


My overall interest is to gain an understanding of the interactions between plant viruses and their insect vectors that regulate the efficient movement of viruses between plant hosts. Specific projects mix fundamental laboratory studies with field studies to investigate; the molecular and cellular interactions of plant viruses with their aphid vectors; the genetics of vector competence in aphid populations; and biological and cultural factors that influence virus epidemics in cereal and potato crops. The long-term goal is to develop sustainable virus disease control practices based on the interference of efficient transmission of viruses by their insect vectors.

Research Focus

There are two main areas of research ongoing in the lab; an investigation of the mechanisms regulating circulative virus transmission by aphids, and the biology and management of Potato virus Y in potato. The circulative viruses we study belong to the Luteoviridae. We have identified two structural virus proteins and one nonstructural protein that regulate the movement of virus through plant hosts and aphid vectors. Transmission is also genetically regulated in aphids in an additive manner by a number of aphid and symbiont genes. Our recent efforts are focused on the aphid and symbiont proteome and discovery of virus interacting proteins. Interestingly it also appears that host proteins may also influence virus uptake by aphids. Potato virus Y is the major disease problem affecting seed potato production in North America and it is responsible for huge economic loss each year. The genetic diversity within this virus is extreme and we are monitoring a major shift in virus strain populations as well as an increase in overall disease levels and the emergence of tuber necrotic strains. Working with growers and the national potato industry, a multi-institutional, multi-disciplinary team of researchers are using fundamental and applied studies to develop and implement a comprehensive virus management plan that is economically and environmentally sustainable.

Outreach and Extension Focus

I work with the national potato industry, growers, seed certification programs and regulatory agencies to develop sustainable practices to reduce virus disease occurrence and the impact of viruses on crop production and quality. A focus in recent years is the development and implementation of the BiNational Canada – U.S. Management Plan for Tuber Necrotic Potato Viruses that helped maintain trade between the countries. This is a project involving the U.S. and Canadian potato industries, USDA, APHIS and CFIA. I serve on the National Potato Council subcommittee for Seed Certification and Plant Disease Management and the North American Plant Protection Organization committee on potato diseases. I am also the project leader on a national, multi-institutional, multidisciplinary project to develop comprehensive strategies to manage Potato virus Y in potato and eradicate the tuber necrotic variants recently introduced into the United States.

Awards and Honors

  • Fellow (2014) American Association for the Advancement of Science
  • Senior Scientist of the Year (2012) USDA, Agricultural Research Service, North Atlantic Area
  • Meritorious Service Award (2009) U.S. Potato Industry
  • Early Career Scientist of the Year (1994) USDA, Agricultural Research Service, North Atlantic Area
  • TW Edminster Award (1992) USDA, Agricultural Research Service

Selected Publications

Journal Publications