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Genetic and biological analysis of colombian phthorimaea operculella granulovirus isolated from tecia solanivora (Lepidoptera: Gelechiidae)

Abstract:

Tecia solanivora (Lepidoptera: Gelechiidae) is an invasive potato pest of the north of South America that recently colonized zones where Phthorimaea operculella (Lepidoptera: Gelechiidae), a taxonomically related insect, was established. Nowadays, both species can be found in most areas in different proportions. The Phthorimaea operculella granulovirus (PhopGV) was found to efficiently control P. operculella and was used as a biopesticide in storage conditions. However, no appropriate biological control methods exist for T. solanivora, and the use of granulovirus isolates would provide a solution. The Colombian Corporation for Agricultural Research (CORPOICA) carried out several T. solanivora larva samplings in Colombia with the aim of finding potential isolates. Five geographical granulovirus isolates from T. solanivora (VG001, VG002, VG003, VG004, and VG005) were found, and molecular analysis by REN profiles shows three different genotypic variants in Colombia. Analysis of their genomes revealed their relatedness to PhopGV. Two isolates exhibited submolar bands in their REN patterns, suggesting a mixture of viral genotypes. These data were confirmed by PCR amplification and sequencing of particular regions of the viral genomes. Their biological activity was assayed on both hosts, T. solanivora and P. operculella. A significantly higher pathogenicity in both hosts was observed with isolates VG001 and VG005 than with isolate VG003 or a Peruvian isolate (from P. operculella) used as a reference in the bioassay. Based on their molecular and biological activity characteristics, VG001 and VG005 isolates should be selected for further analysis in order to establish their potential as biological control agents. Copyright © 2010, American Society for Microbiology.