Biological and Serological Comparisons of Bean Yellow Mosaic Virus(BYMV) Isolates in Japan.

Abstract

To compare biological and serological reactions of 28 bean yellow mosaic virus (BYMV) isolates collected from different hosts and locations in Japan, 15 different bean (Phaseolus vulgaris) cultivars were inoculated with the 28 isolates. Four biological variations (pathotypes I-IV) were observed among the 28 BYMV isolates. Pathotype I systemically infected only one bean cultivar, Honkintoki, out of the 15 cultivars studied. Pathotype II infected systemically Honkintoki, Kentucky Wonder and four other cultivars. Pathotype III infected systemically Honkintoki, Kentucky Wonder, Master Piece and four other cultivars. Pathotype IV infected systemically all 15 bean cultivars. Pathotype II also showed higher seed-transmissibility in broad bean (Vicia faba) than other pathotypes. The 28 BYMV isolates also varied serologically in their reactions in TAS-ELISA to 16 monoclonal antibodies (MAbs) produced against a BYMV isolate and two clover yellow vein virus (ClYVV) isolates. These reactions corresponded, to some degree, to biological variability. MAb-1F3 reacted with pathotypes I, II and III, and with one ClYVV isolate. MAb-2C4 reacted only with pathotype II. MAb-5F2 reacted with all BYMV and ClYVV isolates. MAb-2B4, -2C5, -3F9, -3F11, -4G8 and -4H9 reacted with all BYMV isolates in pathotypes II and III, and with some BYMV isolates in pathotypes I and IV. MAb-1A2 and -2H8 reacted strongly with pathotype III and with two ClYVV isolates. On the other hand, the differences in reactivity of six polyclonal antisera against four BYMV isolates and two ClYVV isolates in DAS-ELISA were not observed clearly. Our results indicate that the BYMV population in Japan is biologically and serologically variable and can be grouped into four pathotypes.