Immunochemical detection of ds-RNA in healthy and virus-infected plants and specific detection of viral ds-RNA by hybridization to labelled complementary DNA.

Double-stranded (ds) RNA was detected in nucleic acid preparations from virus-free leaf tissues of several plant species by radial double-diffusion tests with antiserum raised against polyinosinic : polycytidylic acid [poly(I) : poly(C)]. No significant differences in the concentrations of ds-RNA were detected by such tests in virus-free French bean leaves and those infected with tobacco mosaic virus or tobacco ringspot virus. However, virus-specific ds-RNAs as well as genomic RNAs of both viruses were readily detected and estimated quantitatively by hybridization to 3H-labelled complementary DNA probes. It is concluded that it is not feasible to screen plant material infected with single-stranded RNA viruses by immunochemical tests for virus-associated ds-RNAs.