COMPARISON OF COAT PROTEIN EPITOPES OF 2 ZUCCHINI YELLOW MOSAIC-VIRUSISOLATES

Serological differences between two zucchini yellow mosaic virus (ZYMV ) isolates (ZYMV-169 and ZYMV-M) obtained from two distinct geographic al locations in Japan were determined by mapping epitopes on the coat proteins (CPs) of the two isolates. A total of 45 monoclonal antibodie s (MAbs) against the two isolates were produced and the epitopes on th e CPs were delineated by reacting these MAbs with trypsin-treated ZYMV particles and Escherichia coli-expressed ZYMV CP fragments. Six MAbs of groups I-a and I-b, specific for ZYMV-169, recognised two epitopes in the N-terminal region at amino acids (aa) 1-28 and 6-41 of ZYMV-169 CP. Fourteen MAbs of group II, specific for ZYMV-M, recognised epitop es in the N-terminal region of ZYMV-M CP. Twenty-one MAbs of groups II I-a, III-b(i), III-b(ii), and III-b(iii), reacting with both isolates, recognised four epitopes; one epitope was located in the N-terminal r egion at aa 6-28 and the remaining three epitopes were located in the core region at aa 42-95, 171-227 and 228-259 of ZYMV CPs.