Symptom regulation induced by chicory yellow mottle virus satellite-like RNA

CYMV-T, CYMV-C and CYMV-RS are three strains of CYMV, a nepovirus isolated from chicory in Southern Italy. They are serologically indistinguishable, but display different electrophoretic and analytical ultracentrifugation patterns. In fact the RNAs obtained from CYMV-T, when analyzed in 2.4% polyacrylamide cylindrical gels, showed the presence of a 170,000 mol. wt. satellite-like RNA (CYMV-T Sat RNA) and several other RNAs, whereas CYMV-RS gave only the genomic RNAs and CYMV-C, in addition, some ofthe RNAs present in CYMV-T but not the Sat RNA. When these three strains were assayed on Nicotiana glutinosa L., CYMV-C and CYMV-RS elicited typical necrotic rings, whereas CYMV-T infections were symptomless. The conclusions were drawn that CYMV-T Sat RNA is another low mol. wt. RNA able to display viral disease regulation and that CYMV-T, CYMV-C and CYMV-RS could represent an example of natural oscillation among different stages of RNA satellite emergence.