Restriction endonuclease analysis and mapping of the genomes of granulosis viruses isolated from Xestia c-nigrum and five other noctuid species

Restriction endonuclease analysis was performed on the genomic DNA of granulosis viruses isolated from noctuid species of six genera: Xestia c-nigrum, Autographa gamma, Hydraecia amurensis, Celaena leucostigma, Aletia pallens and Pseudaletia separata. All of the isolates gave very similar restriction endonuclease profiles with only minor variations. An isolate obtained from X. c-nigrum was chosen as the reference genotype, and a genomic library was constructed for this isolate using plasmid vectors. The genome was mapped using EcoRI, BamHI and BglII, and Southern hybridization; the size of the genome was estimated to be 179 kbp. Hybridization of labelled clones to fragments of other isolates revealed that genotypic variation among isolates resulted from changes in restriction sites, and from deletion or insertion of DNA. Comparative restriction mapping revealed that all of the isolates were variants of one virus, even though they originated from different host species.