Plant viruses are widespread in the natural environment and exhibit enormous variation in their structure and composition. Agricultural crops are under constant attack from viruses making an understanding of virus biology a necessity for devising new, more effective approaches to prevent virus disease in plants.
Current work includes a range of studies of viruses of raspberry, an important crop in Scotland in terms of both economics and nutritional health. Viruses are a major cause of disease in raspberry and other woody perennial crops and over time their disease impact increases as the plants become infected with mixtures of different viruses. We have characterised a number of viruses that are known to exist in the UK raspberry crop but are not well understood, (Black raspberry necrosis virus (BRNV), Raspberry leaf mottle virus (RLMV) and Raspberry vein chlorosis virus (RVCV)), to develop molecular diagnostics to be used in The James Hutton Institute High Health Certification Scheme. We also have generated an infectious clone system to aid research into Raspberry bushy dwarf virus (RBDV), a virus of great importance to the raspberry industry because of its involvement in crumbly fruit disease.
Recently we discovered a new, negative-strand RNA virus that is transmitted by eriophyid mites and is responsible for the emerging problem of leaf blotch disorder in many raspberry plantations. This new virus, Raspberry leaf blotch virus (RLBV), belongs to a newly identified group of plant viruses that cause disease in a wide variety of important crops. The molecular structure of these plant viruses shows that they are related to an important group of human and animal-infecting viruses, the bunyaviruses, and further study of RLBV may reveal parallels between the infection processes of these different viruses.
New work has been started to study the resistance reactions of different potato cultivars to aphid-transmitted viruses, such as PVY, and to the nematode-transmitted virus, TRV, which causes spraing in potato tubers.
Past research
In recent years I have researched the mechanism of action of the P19 protein of Tomato bushy stunt virus (TBSV). This is a pathogenicity protein that has a role in suppression of RNA silencing, symptom production in plants, and long- and short-distance movement of the virus within the plant. We have discovered an interaction between P19 and members of the ALY family of plant proteins.
Other aspects of my research have included fundamental studies, primarily on Tobacco rattle virus (TRV), an important pathogen of potatoes in Scotland, Europe and North America, and Pea early-browning virus (PEBV), to understand the mechanism of transmission of these viruses by nematodes, a process that is central to the diseases they cause in the field.
More recently it has been realised that plant viruses can be developed into tools that have great potential for functional genomic analysis of plants. I have engineered TRV, and the related viruses PEBV and Pepper ringspot virus (PepRSV), to be useful as vectors for gene expression and gene silencing in a variety of plant species.