Biomolecular and serological methods to identify strains of cucumber mosaic cucumovirus on tomato 1

Abstract

Biomolecular and serological methods were used to classify 52 Italian isolates of cucumber mosaic cucumovirus (CMV) into S and WT subgroups. Two synthetic oligonucleotides, specific for the coat‐protein genes of the S and WT subgroups, were designed. These probes, used in Northern blot assays, were able to identify viral RNAs present in total nucleic‐acid extracts from fruits and leaves of infected field tomatoes. CMV‐specific primers, flanking the coat‐protein gene, were used to amplify, by RT‐PCR assay, a fragment of approximately 870 bp from either dsRNA replicative intermediates or purified genomic ssRNA. The restriction pattern analysis of the PCR product distinguished between the two subgroups. Monoclonal antibodies specific for CMV isolates belonging to the S and WT subgroups were produced. Five of these were able to detect and distinguish the strains in indirect ELISA using crude extracts from field samples. The three strategies gave concordant results and were useful in detecting and typing CMV subgroups on tomato.