Serological characterization of papaya ringspot virus isolates in Taiwan

Twenty-seven isolates of papaya ringspot virus (PRSV) were obtained from Taiwan. Differences in symptoms were observed. In addition to such isolates as necrotic severe mottle (SMN), severe mottle (SM) and mild mottle (M), another mottle type with deformation (DF) was isolated. Ail the isolates of PRSV and PRSV-W (PRSV type W) examined were serologically indistinguishable as determined by polyclonal antibodies-rabbit antisera to PRSV, but were consistently distinguishable with monoclonal antibodies (MAbs). Those isolates were raised against the PRSV. The virus isolates that reacted with the MAbs to PRSV were selected and applied to compare the antigenic specificity of the PRSV strain. Moreover, the immunoreactivities of the MAbs were compared with polyclonal rabbit serum to detect PRSV in foliar tissue by enzyme-linked immunosorbent assay (ELISA). Eleven selected MAbs were differentiated into five sero-groups according to sere-reaction patterns of ELISA index with 27 isolates of PRSV and PRSV-W. It was assumed that at least five antigenic epitopes were identified. Distinct results were obtained in application of MAb to ELISA for detecting PRSV strains in cucurbitaceous plants.