ABSTRACT
Cydia pomonella granulovirus is a natural pathogen for Cydia pomonella that is used as a biocontrol agent of insect populations. The study of granulovirus virulence is of particular interest since the development of resistance in natural populations of C. pomonella has been observed during the long-term use of the Mexican isolate CpGV. In our study, we present the genomes of 18 CpGV strains endemic to southern Russia and from Kazakhstan, as well as a strain included in the commercial preparation "Madex Twin", which were sequenced and analyzed. We performed comparative genomic analysis using several tools. From comparisons at the level of genes and protein products that are involved in the infection process of virosis, synonymous and missense substitution variants have been identified. The average nucleotide identity has demonstrated a high similarity with other granulovirus genomes of different geographic origins. Whole-genome alignment of the 18 genomes relative to the reference revealed regions of low similarity. Analysis of gene repertoire variation has shown that BZR GV 4, BZR GV 6, and BZR GV L-7 strains have been the closest in gene content to the commercial "Madex Twin" strain. We have confirmed two deletions using read depth coverage data in regions lacking genes shown by homology analysis for granuloviruses BZR GV L-4 and BZR GV L-6; however, they are not related to the known genes causing viral pathogenicity. Thus, we have isolated novel CpGV strains and analyzed their potential as strains producing highly effective bioinsecticides against C. pomonella.
