Physical mapping and molecular cloning of caulimovirus DNA

John Innes Institute, Colney Lane, Norwich NR4 7UH, U.K. Native DNA of both mirabilis mosaic virus (MMV) and the previously undescribed thistle mottle virus (ThMV) formed multiple bands when analysed by gel electrophoresis, thereby resembling DNA from other caulimoviruses. Denaturation showed that ThMV DNA had three discontinuities (one in one strand and two in the other) and that MMV DNA had four discontinuities which mapped in the same relative positions as those in DNA of figwort mosaic virus (FMV). DNA from carnation etched ring virus (CERV), FMV, MMV and ThMV was cloned in bacterial plasmids. Cloned full-length DNA of CERV, FMV or MMV was infective for plants. Comparisons by restriction mapping and Southern transfer hybridization among DNA from cauliflower mosaic virus, CERV, FMV, MMV and ThMV suggest that these viruses are distinct members of the caulimovirus group. Keywords: caulimovirus, infective cloned DNA, physical mapping, discontinuities Received 18 April 1983; accepted 16 June 1983.