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This joint international conference was at Cornell University, USA. Ithaca is a beautiful town which is the heart of the Finger Lakes Region of the New York State. The meeting brought together 173 scientists from North America, South America, Europe, Australia, Asia, and Africa working on all aspects of virus epidemiology and ecology. The objective of the meeting was to broaden the scope beyond the agricultural setting to include natural landscape and the interactions between these ecosystems that can impact plant virus disease emergence, development, diversity and maintenance.
The conference was divided into four themes, with each day beginning with a symposium that featured a keynote speaker and invited presentations in the mornings. This was followed by 15 minute oral presentations after lunch and then a short session in which selected poster authors described briefly their posters. A poster viewing session and social time then followed in the evening prior to dinner.
The first day of the conference was on plant virus epidemiology and etiology. The presentation that really caught my attention was on epidemiology of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) in East Africa presented by James P. Legg (IITA, Tanzania). He reported that the severe CMD pandemic spread has arisen from virus recombination and inter-species synergy whilst the CBSD pandemic is a ‘new encounter’ situation. CMD pandemic spread has been tightly linked with the appearance of super- abundant Bemisia tabaci populations, in contrast to CBSD, where outbreaks have occurred 3-10 years after whitefly population increases. During the poster session, Titus Alicai (NaCRRI, Uganda) indicated that CBSD is now the most serious threat to cassava production in the entire East and Central Africa. Two virus species associated with CBSD are Cassava brown streak virus (CBSV) and Cassava brown streak Uganda virus (CBSUV) with incidences and yield loss of up to 100% reported. Maruthi M. N. Gowda’s (NRI, UK) poster described two genetic groups of the virus causing CBSD in East Africa. Isolates from Tanzania and Mozambique produced the most severe symptoms and caused dieback of Nicotiana plants 2-3 weeks after inoculation, while the Ugandan isolates produced relatively less severe symptoms.
In the same session, I presented my PhD work which showed the widespread incidence of Turnip yellows virus (TuYV) infection in oilseed rape crops in England. Incidences of infections detected from oilseed rape crops between 2007-2010 in Lincolnshire, Warwickshire and Yorkshire range between 0 and 100%. Preliminary phylogenetic analyses of nucleotide sequences of both P3 and P0 genes showed the existence of more than one genetic group of TuYV isolates infecting oilseed rape plants in each county.
The second day theme was virus ecology and evolution. Israel Pagan (Pennsylvania State University, USA) presented an interesting topic on long- term evolution of Luteoviridae. Molecular clock analysis suggested that the origin of currently circulating species occurred within the last four millennia, with intra-specific genetic diversity arising within the last few hundred years. As a consequence, speciation seems to be associated with the rise and expansion of agricultural systems. Wendy Monger (Fera, UK) gave a presentation on next generation sequencing of plant viruses, an emerging powerful tool and technology which i s being exploited for identification of pathogens, including viruses.
The theme for the third day symposium was vector biology / virus transmission. The talk which interested me most was on an aphid gut binding peptide which was presented by Bryony Bonning (Iowa State University, Ames, USA). A twelve-residue gut binding peptide (GBP3. 1) that binds to the midgut and hindgut of the pea aphid has been identified. GBP3. 1 reduced uptake of Pea enation mosaic virus from the pea aphid gut into the hemocoel, and also bound to the gut epithelia of the green peach aphid and the soybean aphid. These results present a novel and broad spectrum approach for the management of plant viruses. On Wednesday evening we took a trip to the Wagner Vineyard and Micro- Brewery located on the east side of Seneca Lake, the largest and deepest of the Finger Lakes in the region. The conference dinner was held there.
The last day of the conference was on virus disease management/detection/ diagnosis. Of particular interest was the effective virus detection system developed by Maja Ravnikar (National Institute of Biology, Ljubljana) for Pepino mosaic virus (PepMV) that threatens tomato industry worldwide. Several sensitive one-step RT-qPCR assays have been developed for the detection of low concentrations of PepMV and for discriminating currently circulating PepMV genotypes.
Generally, it was an excel lent conference where I identified future collaborators and acquired ideas knowledge. I would like to thank the University of Warwick, the British Society for Plant Pathology and the conference organisers, especially Dr Stewart Gray, for their financial support, which enabled me to attend the workshop. I would also like to thank my supervisors Dr John Walsh and Dr Carol Jenner for the opportunity to present at the conference.
Elvis Asare-Bediako
University of Warwick
