Applied and Environmental Microbiology (2005) 71, 4254-4262

Oihane Simón, Trevor Williams, Miguel López-Ferber and Primitivo Caballero (2005)
Functional importance of deletion mutant genotypes in an insect nucleopolyhedrovirus population
Applied and Environmental Microbiology 71 (8), 4254-4262
Abstract: A Nicaraguan isolate of a nucleopolyhedrovirus (SfNIC) that attacks the fall armyworm, Spodoptera frugiperda, survives as a mixture of nine genotypes (SfNIC A to I) that all present genomic deletions, except variant B (complete genotype). Sequencing of cloned restriction fragments revealed that genotypic variants lack between 5 and 16 of the open reading frames present in a contiguous sequence of 18kb of the SfNIC genome. The absence of oral infectivity of SfNIC-C and -D variants is related to the deletion of the pif and/or pif-2 gene, while that of SfNIC-G remains unexplained. The presence of open reading frame 10, homolog of Se030, also appeared to influence pathogenicity in certain variants. Previous studies demonstrated a significant positive interaction between genotypes B and C. We compared the median lethal concentration of single genotypes (A, B, C, D, and F) and co-occluded genotype mixtures (B+A, B+D, B+F, A+C, and F+C in a 3:1 ratio). Mixtures B+A and B+D showed increased pathogenicity, although only B+D restored the activity of the mixture to that of the natural population. Mixtures of two deletion variants (A+C and F+C) did not show interactions in pathogenicity. We conclude that minority genotypes have an important influence on the overall pathogenicity of the population. These results clearly demonstrate the value of retaining genotypic diversity in virus-based bioinsecticides.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Trevor Williams, Primitivo Caballero, Oihane Simón

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
molecular biology - genes
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Spodoptera frugiperda		Nicaragua
Alphabaculovirus spofrugiperdae (entomopathogen)	Spodoptera frugiperda		Nicaragua