Serological differences between some isolates of bean yellow mosaic virus.

The degree of serological relatedness of three isolates of bean yellow mosaic virus (BYMV) was studied. One common antigenic group (m) was demonstrated in all 3 isolates. In addition, another antigenic group (a) was demonstrated in the isolate FvM1. This group was absent from the isolates TpM3 and TpM11, in which the antigenic group n was found. Antisera to the 3 isolates contained the corresponding antibody groups. The antibody group (M) shared by all 3 BYMV isolates was present in the FvM1 antiserum in a level only a little higher than the second antibody group (A). Antisera to TpM3 and TpM11 isolates showed only a low titre of M antibody, while the second antibody group (N) reached titres from 512 to 1024. Cross-absorption tests revealed serological identity of both isolates of the "necrotic type" (TpM3 and TpM11) and allowed to estimate the degree of their serological relatedness to representatives of the "mosaic type" isolates of BYMV (FvM1).