Enzyme-linked immunosorbent assay for detection of red clover necrotic mosaic virus in the host plants.

Detection of three isolates of red clover necrotic mosaic virus (RCNMV) representing A, B, and C serotypes was experimentally proved in 18 host plant species by enzyme-linked immunosorbent assay (ELISA). In all plant species tested, the homologous serotype reactions showed high selectivity. Individual virus serotypes could be reliably detected in the extracts of infected plants only with the homologous IgG fraction. Group specific detection of RCNMV without serotype determination was possible using the mixture of IgG directed to all virus serotypes occurring in the region of investigation. Intensity of positive reaction of optimally diluted IgG with the extracts from infected plants differed markedly from that of negative reaction and from the reaction background. The latter depended on the quality of serum used for the IgG preparation. For detection of small amounts of RCNMV, virus infectivity test on indicator plants was more sensitive than ELISA.