ABSTRACT
Sobemoviruses are transmitted by beetles, through seeds, and mechanically, each to a narrow range of plant species. A number of viruses have some properties sufficiently similar to southern bean mosaic virus (SBMV) to be considered possible members of the Sobemovirus group. The three new viruses, those of velvet tobacco mottle (VTMoV), solanum nodiflorum mottle (SNMV), and subterranean clover mottle (SCMoV), have been shown to share a number of properties characteristic of Sobemoviruses. SBMV, on which more vector work has been done, can be transmitted without an incubation period by its chrysomelid beetle vector. The virus appears to enter the haemolymph and can continue to be transmitted by the insect for some days after feeding on infected plants. The integrity of the SBMV particle is dependent on divalent metal ions and the function of both calcium and magnesium has been studied extensively.
