Molecular biology of plant virus-host and virus-vector interactions

Aims: To understand the role and function of virus encoded proteins and their interactions in the pathogenicity and spread of plant virus diseases.

Background: Potato is an important crop in Scotland with around about 1.3 million tonnes of potatoes produced and 76,000 tonnes of seed exported to over 30 countries (outside the EU). Pests and diseases are a major constraint to the industry causing economic losses by decreased tuber yield and quality, and rejection of exports.

Soil-borne potato mop-top virus (PMTV) and aphid transmitted potyviruses (principally PVY) are economically important problems in potato seed crops that are difficult to control. No sources of resistance to PMTV have been identified in Solanum tuberosum and there are no reliable methods to control the spread of PMTV by the soil-borne plasmodiophorid vector Spongospora subterranea (that also causes powdery scab disease on potato tubers).

In addition, the application of insecticides to control the spread of aphid-borne potato potyviruses such as PVY is not effective. It is expected that aphid populations may build up earlier in the season and aphid-borne virus spread may increase because of the warmer temperatures predicted with environmental change.

Studying the molecular interactions between virus-host and virus-vector will provide a deeper understanding of the mechanisms of virus transmission and host resistance. The practical outputs of the work will be to identify new sources of resistance and more effective methods of disease control.

Current focus: Investigating a novel resistance to PVY (and other potyviruses) that we have discovered in Solanum tuberosum Group Phureja germplasm; the effect of heat stress on virus resistance and the molecular basis of mature plant resistance in potato.

Studies on the localisation and function of PMTV TGB movement proteins have revealed that PMTV infection includes a nuclear/nucleolar phase important for long distance movement in the vascular system and that the movement protein TGB1 determines nucleolar targeting and we are investigating a host factor that mediates nuclear association. In vitro culture of potato 'hairy root' systems have been established to investigate the molecular mechanism of vector transmission of PMTV.

Other research in the lab concerns working with partners in Africa to improve seed potato production systems and collaboration with Ziejiang Academy of Agricultural Sciences on soil-borne viruses.

NSF/BBSRC Project on The spatial epidemiology of a vector-borne plant virus (PVY) with partners in USA led by Professor A Power, University of Cornell.