title: Deletion genotypes reduce occlusion body potency but increase occlusion body production in a Colombian Spodoptera frugiperda nucleopolyhedrovirus population.
abstract: A Colombian field isolate (SfCOL-wt) of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is a mixture of different genotypes. To evaluate the insecticidal properties of the different genotypic variants, 83 plaque purified virus were characterized. Ten distinct genotypes were identified (named A through J). SfCOL-A was the most prevalent (71±2%; mean ± SE) showing a PstI restriction profile indistinguishable to that of SfCOL-wt. The remaining nine genotypes presented genomic deletions of 3.8 - 21.8 Kb located mainly between nucleotides 11,436 and 33,883 in the reference genome SfMNPV-B, affecting the region between open reading frames (ORFs) sf20 and sf33. The insecticidal activity of each genotype from SfCOL-wt and several mixtures of genotypes was compared to that of SfCOL-wt. The potency of SfCOL-A occlusion bodies (OBs) was 4.4-fold higher than SfCOL-wt OBs, whereas the speed of kill of SfCOL-A was similar to that of SfCOL-wt. Deletion genotype OBs were similarly or less potent than SfCOL-wt but six deletion genotypes were faster killing than SfCOL-wt. The potency of genotype mixtures co-occluded within OBs were consistently reduced in two-genotype mixtures involving equal proportions of SfCOL-A and one of three deletion genotypes (SfCOL-C, -D or -F). Speed of kill and OB production were improved only when the certain genotype mixtures were co-occluded, although OB production was higher in the SfCOL-wt isolate than in any of the component genotypes, or mixtures thereof. Deleted genotypes reduced OB potency but increased OB production of the SfCOL-wt population, which is structured to maximize the production of OBs in each infected host.
authors.affiliation: Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, Mutilva Baja, Navarra, Spain ; Corporación Colombiana de Investigación Agropecuaria (CORPOICA), Bogotá, Colombia.
authors.forename: Gloria
authors.initials: G
authors.lastname: Barrera
authors.forename: Trevor
authors.initials: T
authors.lastname: Williams
authors.forename: Laura
authors.initials: L
authors.lastname: Villamizar
authors.forename: Primitivo
authors.initials: P
authors.lastname: Caballero
authors.forename: Oihane
authors.initials: O
authors.lastname: Simón
mesh_terms: D000818:Animals; D017353:Gene Deletion; D005814:Genes, Viral; D014644:Genetic Variation; D005838:Genotype; D054884:Host-Pathogen Interactions; D017924:Nucleopolyhedroviruses / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D016366:Open Reading Frames; D018411:Spodoptera / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics
chemical_list: D014764:Viral Proteins