Variation in Cydia pomonella Granulosis Virus Isolates and Physical Maps of the DNA from Three Variants

Abstract

SUMMARYCydia pomonella granulosis viruses (CpGV) from seven different sources in Europe, America and New Zealand were compared by restriction enzyme analysis. Most samples were indistinguishable from the Mexican isolate (CpGV-M). Isolates from Russia (CpGV-R) and England (CpGV-E) showed small genotypic differences. CpGV-E was shown to be a mixture of two variants, E1 and E2. CpGV-E1 was indistinguishable from CpGV-M. A physical map of CpGV-M was constructed for the enzymes EcoRI, BamHI, HindIII, Sinai and ApaI. A comparison of fragment profiles allowed construction of maps for CpGV-R and CpGV-E2. Relative to CpGV-M, CpGV-R had a single deletion of 2.4 kbp and CpGV-E2 was modified in one area resulting in an additional EcoRI site, a shift in a BamHI site and in total about 1 kbp more DNA. The map was orientated by locating the granulin gene using the cloned granulin gene from Trichoplusia ni GV as a probe. There was no significant difference between the infectivities of the Mexican, Russian and English isolates for neonate larvae.

Comprehensive physical map of the Cydia pomonella granulovirus genome and sequence analysis of the granulin gene region.

“…A detailed physical map is a prerequisite for such work. We previously produced a physical map for the CpGV-M strain of the virus (Crook et al, 1985) but this contained only 36 restriction sites. Also, although restriction profiles of the CpGV-M isolate contained no visible submolar bands, most baculovirus isolates contain a mixture of genotypes and it would be highly desirable to eliminate the possibility of genotypic variability by working with a cloned strain of the virus.…”

Screening Cydia pomonella granulovirus (CpGV) isolates via comparative bioassays

“…Despite the acceptance of the similarity of the lines, the LC50 was nearly half of others and 0.6 of the Mexican isolate, however, that was not significant. The calculated LC50 value for the Mexican isolate in the present experiment was 2724 OB/ml, comparable with 2600 OB/ml (7). The slopes of probit lines were promising and had no significant difference, but the similarity hypothesis of probit lines rejected.…”

“…Most of CpGV products that are commercialized and used for codling moth control are based on the so-called Mexican (M) isolate, which was isolated and identified in 1963 (5). Two further described isolates are a Russian (R) isolate in 1974 (6) and an English (E) isolate from laboratory (7). The geographic isolates of CpGV have been reported from different locations in the world (5)(6)(7)(8).…”

“…Two further described isolates are a Russian (R) isolate in 1974 (6) and an English (E) isolate from laboratory (7). The geographic isolates of CpGV have been reported from different locations in the world (5)(6)(7)(8). These isolates can be distinguished by restriction fragment length polymorphisms (RFLPs) (7-9), single nucleotide polymorphisms (SNPs) in highly conserved genes (10) and in their phylogenetic position based on genome sequencing (4).…”

“…The biological activities of the CpGV isolates have been evaluated in field and, under laboratory conditions mostly on neonate larvae or 5th instar larvae (11)(12)(13). The CpGV's biological activity parameters, such as LC50, LD50 and LT50 were discussed (1,6,7,11). The LC50 bioassays have been conducted not only on surface of artificial media, leaves (13) or fruits, but also in whole volume of media (11) during bioassay for 7 or 14 days permanently or partially.…”