Abstract
The particles of two serologically unrelated viruses, Solanum nodiflorum mottle (SNMV) and lucerne transient streak (LTSV), contain linear single-stranded RNA-1 (mol. wt. approx. 1.4 x 106), and linear and circular RNA molecules of mol. wt. approx. 1.2 x 105 (RNA-2). SNMV RNA-2 is reported to be part of the virus genome, but LTSV RNA-2 is a satellite-like RNA which is not necessary for the replication of LTSV RNA-1 or for the production of virus particles. When inoculated alone, SNMV RNA-2 did not infect plants but when inoculated with LTSV RNA-1 it replicated, modified the symptoms induced by LTSV and was packaged in particles with the serological specificity of LTSV. Thus, SNMV RNA-2 behaves like a satellite RNA in its interactions with LTSV. LTSV cultures containing LTSV RNA-2 or SNMV RNA-2, or lacking RNA-2, were distinguishable by reactions in some plant species but their particles were indistinguishable serologically, in sedimentation rate and in buoyant density in CsCl.