Properties of a strain of tobacco mosaic virus (TMV-S) originally isol
ated from soybean (Glycine max) were compared with those of two isolat
es of the common strain of TMV (ATCC PV-135 and PV-220), one TMV strai
n infecting bean (Phaseolus vulgaris) (TMV-B, ATCC PV-742), and sunnhe
mp mosaic virus (SHMV, ATCC PV-744). The virion capsid protein subunit
s of the common and soybean strains were 21 kDa, Reduced and alkylated
capsid proteins of TMV-B and SHMV migrated as two bands and more rapi
dly than capsid proteins of the common and soybean strains in acrylami
de gels containing sodium dodecyl sulfate. Host symptomatology, serolo
gical assays, particle morphology, and gel electrophoresis of the mono
partite genome (6.4 kb) and whole virions demonstrated that TMV-S is c
losely related to the common strain of TMV but only distantly related
to SHMV and TMV-B, which should be regarded as an SHMV isolate.