Differentiation of Dasheen Mosaic Potyvirus Isolates Based on Variability in the Apparent Size of the Capsid Protein in Western Blots

The capsid protein (CP) sizes of seven dasheen mosaic virus (DsMV) isolates and one isolate of vanilla mosaic virus were estimated to be 38–47 kDa and 47 kDa, respectively, based on Western blot analyses using DsMV polyclonal antiserum. The CP sizes of 12 other potyviruses were estimated to be 31–36 kDa. Apparent CP sizes of the DsMV isolates extracted from their original hosts were 47 kDa (Xanthosoma caracu), 45 kDa (Colocasia esculenta, Zantedeschia aethiopica), and 38–46 kDa (Caladium hortulanum). Propagation in seedlings of Philodendron selloum did not affect the CP sizes of any of the individual DsMV isolates. The same characteristic CP sizes were also detected in Western blot analyses of these isolates, using polyclonal antisera of eight other potyviruses, or using Agdia Poty 1 monoclonal antiserum, and using three monoclonal antisera of papaya ringspot virus type W. The apparent CP size and pattern of apparent breakdown products as revealed by Western blots of extracts from infected aroids may be used in the characterization and differentiation of DsMV isolates.