Serological relationships between the nucleocapsids of some planthopper-borne rhabdoviruses of cereals

Leaves infected with barley yellow striate mosaic virus (BYSMV) from Italy, wheat chlorotic streak virus (WCSV) from France, northern cereal mosaic virus (NCMV) from Japan, maize sterile stunt virus (MSSV) from Australia or Shiraz maize rhabdovirus (SMRV) from Iran were homogenized in buffered 1% Nonidet P-40, releasing intact nucleocapsids. These (except SMRV) were trapped on electron microscope grids using appropriate antisera and tested by decoration with serial dilutions of antisera to BYSMV, NCMV, MSSV, Moroccan wheat rhabdovirus (MWRV), wheat rosette stunt virus (WRSV) from China, and maize mosaic virus (MMV) from Venezuela. The results suggest that BYSMV and NCMV, though related, are distinct viruses; MWRV and WCSV are strains of BYSMV; MSSV is intermediate between BYSMV and NCMV but may be considered a strain of BYSMV; WRSV is a strain of NCMV; and MMV and SMRV are unrelated to each other and to the other viruses tested. SMRV was morphologically quite different from BYSMV, NCMV, WCSV and MSSV, all of which had the same morphology.