Gagarinova, Alla , Wang, Aiming .
Analysis of two closely related Soybean mosaic virus (SMV) isolates, differing in their ability to overcome soybean Rsv4 resistance gene.
SMV belongs to the family Potyviridae and is one of the most destructive viral pathogens of soybean. Two SMV isolates, SMV-L and SMV-LRB, differing in their ability to overcome soybean Rsv4 resistance gene were obtained form an experimental field in London, Ontario, Canada. The entire genomes of these two isolates were cloned and sequenced. The two isolates are 9585 nucleotide (nt) in length, excluding the poly-A tails, and share 99.6 % identity on nt and amino acid (aa) levels. Both isolates have 131 and 252 nt 5’- and 3’-untranslational regions, respectively. The deduced polyprotein of each isolate consists of 3066 aa with a calculated molecular mass of 350 kDa. Phylogenetic analysis indicated that the two isolates are most closely related to the G2 group of SMV isolates in the USA. Pathogenicity tests showed that like other G2 isolates, both SMV-L and SMV-LRB can infect soybean cultivars carrying Rsv3 resistance gene but not cultivars carrying Rsv1 and Rsv1-h resistance genes. However, only the SMV-LRB isolate but not the SMV-L isolate, is able to overcome resistance of Rsv4 resistance locus. We are currently working on testing full length infectious clones of the two isolates, which will be used to identify viral genes responsible for breaking the Rsv4 resistance. Results of the sequence comparison, phylogenetic analysis, and recombination prediction as well as progress of SMV infectious clone construction and follow-up identification of viral resistance-breaking determinants will be discussed.
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1 - The University of Western Ontario, Department of Biology, Biological & Geological Building, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
2 - Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre
Soybean mosaic virus
viral resistance-breaking determinants
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM