Current Research

• Plant virology
• Plant-virus-vector interactions
• Potato viruses

Aims: to understand the role and function of virus encoded proteins and identify host factors required for virus infection and transmission principally in relation to the potato viruses potato mop-top (PMTV) and Y (PVY).  Soil-borne PMTV and aphid transmitted PVY are economically important problems in potato seed and ware 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. By studying plant-virus-vector interactions to identify host proteins that play important roles in the infection process we will gain a deeper understanding the mechanisms of virus transmission and resistance. 

Current focus: We have recently discovered a novel resistance to potyviruses in Solanum phureja germplasm and studies are ongoing to map and characterise this gene.  Studies on 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.  Systems are being established to investigate the molecular mechanism of vector transmission of PMTV.  

News

New grant from Scottish Government International:

Strengthening Potato Production in Malawi

Partners are Paul Demo, CIP potato seed specialist, Malawi and Obed John Mwenye, Dept. Agriculture Research Services, Bvumbwe Research Sataion.

We will address the key issues identified within a Scottish Government supported survey, which explored the constraints on the potato crop within the Malawian agricultural system. The project aims to contribute to poverty reduction and food security through strengthening the development of sustainable potato production and marketing systems for improved productivity and trade.

Total award for 2010 - 2013: £399,900

Research History

Previously my group investigated novel antibody-based diagnostic techniques. In collaboration with others we showed that antibody fragments derived from naïve synthetic libraries of antibody genes can be incorporated into standard tests that detect the plant viruses Beet necrotic yellow vein virus and Potato leaf roll virus as well as tests based on immune reagents (these projects were funded by EC, AIR-CT-94-1046 and QLRT-1999-PL-1116).

Recent Publications

• Wright, K., Cowan, G., Lukhovitskaya, N., Tilsner, J., Roberts, A., Savenkov, E and Torrance, L. 2010. The N-terminal domain of PMTV TGB1 movement protein is required for nucleolar localization, microtubule association and long-distance movement. Molecular Plant-Microbes Interactions (accepted).
• Verchot-Lubicz, J., Torrance, L., Solovyev, A.G., Morozov, S.Y., Jackson, A.O. and Gilmer, D. 2010. Viral movement strategies employed by triple gene block encoding viruses. Molecular Plant-Microbe Interactions (accepted).
• Tilsner, J., Cowan, G.H., Roberts, A.G., Chapman, S., Ziegler, A., Savenkov, E. and Torrance, L. 2010. Plasmodesmal targeting and intercellular movement of potato mop-top pomovirus is mediated by a membrane anchored tyrosine-based motif on the lumenal side of the endoplasmic reticulum and the C-terminal transmembrane domain in the TGB3 movement protein. Virology 402, 41-51.
• Chichkova, N.V., Shaw, J., Galiullina, R.A., Drury, G.E., Tuzhikov, A.I., Kim, S.H., Kalkum, M., Hong, T.B., Gorshkova, E.N., Torrance, L., Vartapetian, A.B. and Taliansky, M.E. 2010. Phytaspase, a relocalisable cell death promoting plant protease with caspase specificity. EMBO Journal. (doi:10.1038/emboj.2001.1)
• Ziegler, A., Cowan, G.H. and Torrance, L. 2009. Comparative sequence anaylsis and serological and infectivity studies indicate that cocksfoot mild mosaic virus is a member of the genus Panicovirus. Archives of Virology 154, 1545-1549.
• Torrance, L., Lukhovitskaya, N.I., Schepetilnikov, M.V., Cowan, G.H., Ziegler, A. and Savenkov, E.I. 2009. Unusual Long-Distance Movement Strategies of Potato mop-top virus RNAs in Nicotiana benthamiana. Molecular Plant-Microbe Interactions 22, 381-390.
• Swanson, M.M., Fraser, G., Daniell, T.J., Torrance, L., Gregory, P.J. and Taliansky, M.E. 2008. Viruses in soils: morphological diversity and abundance in the rhizosphere. Annals of Applied Biology 155, 51-60. (doi:10.1111/j.1744-7348.2009.00319.x)
• Torrance, L., Cowan, G.H., Gillespie, T., Ziegler, A. and Lacomme, C. 2006. Barley stripe mosaic virus-encoded proteins triple-gene block 2 and γb localize to chloroplasts in virus-infected monocot and dicot plants, revealing hitherto-unknown roles in virus replication. Journal of General Virology 87, 2403-2411.
• Torrance, L., Igor, A., Gabrenaite-Verhovskaya, R., Cowan, G., Mäkinen, K. and Taliansky, M.E. 2006. An unusual structure at one end of potato potyvirus particles. Journal of Molecular Biology 357, 1-8.
• Haupt, S., Cowan, G.H, Ziegler, A., Roberts, A.G., Oparka, K.J. and Torrance, L. 2005. Two plant-viral movement proteins traffic in the endocytic recycling pathway. Plant Cell 17, 164-181.
• Torrance, L. and Koenig, R. 2004. Genus Furovirus. In: Virus Taxonomy, eighth report of the international committee on taxonomy of viruses. Eds, van Regenmortel, M.H.V., Fauquet, C. and Bishop, D.H.L., Harcourt International.
• Cowan, G.H., Lioliopoulou, F., Ziegler, A. and Torrance, L. 2002. Subcellular localisation, protein interactions and RNA binding of Potato mop-top virus triple gene block proteins. Virology 298, 106-115.
• Baratova, L.A., Efimov, A.V., Dobrov, E.N., Fedorova, N.V., Hunt, R., Badun, G.A., Ksenofontov, A.L., Torrance, L. and Järvekülg, L. 2001. In situ Spatial Organization of Potato Virus A Coat Protein Subunits as Assessed by Tritium Bombardment. Journal of Virology 75, 9696-9702.
• Sasaya, T., Torrance, L., Cowan, G.H., Ziegler, A. 2000. Aphid transmission studies using Potato virus Y helper component proteins expressed from a Potato virus X vector. Journal of General Virology 81, 1115-1119.

Selected Publications - Virus Diagnostics

• Zakri, A.M., Ziegler, A., Torrance, L., Fischer, R. and Commandeur, U. 2010. Generation and characterization of a scFv against the purified coat protein of the geminivirus tomato leaf curl New Delhi virus. Archives of Virology. (doi: 10.1007/s00705-010-0591-6)
• Al-Mrabeh, A., Ziegler, A., Cowan, G. and Torrance, L. 2009. A fully recombinant ELISA using in vivo biotinylated antibody fragments for the detection of potato leaf roll virus. Journal of Virological Methods 159, 200-205.
  
• Torrance, L., Ziegler, A., Pittman, H., Paterson, M., Toth, R and Eggleston, I. 2006. Engineering single-chain antibodies and oriented immobilisation for biosensor and biotechnological applications. Journal of Virological Methods 134 (1-2), 164-170.
• Torrance, L. 2005. Serological Methods. In Proceedings Bee Research and Virology in Europe (BRAVE) meeting, 24-26 April 2005, pp 109-114.
• Jones, A.T., Cowan, G.H., McGavin, W.J., Roberts, I.M. and Torrance, L. 2004. Production and properties of monoclonal antibodies to solanum nodiflorum mottle sobemovirus. Annals of Applied Biology 146, 321-325.
• Ziegler, A. and Torrance, L. 2002. Applications of recombinant antibodies in plant pathology. Molecular Plant Pathology 3, 401-407.
• Ziegler, A., Cowan, G.H., Torrance, L., Ross, H.A. and Davies, H.V. 2000. Facile assessment of cDNA constructs for expression of functional antibodies in plants using the potato virus X vector. Molecular Breeding 6, 327-335.
• Reavy, B., Ziegler, A., Diplexcito, J., Macintosh, S.M., Torrance, L. and Mayo, M. 2000. Expression of functional recombinant antibody molecules in insect cell expression systems. Protein Expression and Purification 18, 221-228.

Posters

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Attachment	Size
AFPTEST: Standard test kits based on novel recombinant antibodies for detection of harmful plant viruses	203.22 KB
Detection of Potato Mop-Top Virus in potato tissues and soil	134.22 KB
Multifunctional role of Potato mop-top virus movement protein TGB2	419.36 KB
Viruses in Soil	494.3 KB
TGB2 movement proteins of the Hordei type localise to chloroplasts	265.31 KB
Virus-like particles from Antarctic dry valley soil	915.72 KB
Caspase-resistant VirD2 protein provides enhanced gene delivery and expression in plants	409.12 KB
Environmental Change - Impacts on pests and Diseases	725.69 KB
PVY transmission by aphids: implications of the host plant and the virus isolate	2.19 MB
The coordinated action of potato mop-top virus triple gene block movement proteins in viral cell-to-cell transport	5.96 MB