Premium
Phenotypic characteristics and relative proportions of three genotypic variants isolated from a nucleopolyhedrovirus of Spodoptera exigua
Author(s) -
Muñoz Delia,
Escudero Iñigo Ruiz,
Caballero Primitivo
Publication year - 2000
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1046/j.1570-7458.2000.00740.x
Subject(s) - biology , exigua , genotype , larva , spodoptera , instar , virology , veterinary medicine , strain (injury) , noctuidae , gene , genetics , botany , recombinant dna , medicine , anatomy
US2A, US2D, and US2F are three in vivo cloned genotypic variants from the wild‐type strain of a Spodoptera exigua nucleopolyhedrovirus (SeMNPV) isolated in Florida (USA) and is the active component of the commercial bioinsecticide Spod‐X®. These variants were compared in terms of pathogenicity ( LD 50 ), speed of kill (expressed as mean time to death) and viral progeny productivity (OBs/larva). LD 50 values were similar for the three cloned genotypes. The mean time to death value for US2D (113.7 h) was significantly higher than those of US2A (31.7 h) and US2F (27.8 h). Virus yield was determined for L 4 larvae infected with the estimated LD 99 . US2D infected larvae attained higher weight than those infected with US2A and US2F, and produced a higher OB yield than larvae infected with US2A or US2F. An outstanding feature of US2F, in contrast to US2A and US2D, was its inability to disrupt the teguments of NPV‐killed larvae. To study the relative proportion of the three genotypic variants throughout successive passages, S. exigua larvae were originally infected with a viral inoculum containing a 1:1:1 mixture of the three genotypes. After three successive passages, US2D was no longer detected in either of the three replicate experiments performed, while US2A was the predominant genotype in all of them, and US2F remained at similar proportions throughout the three passages. The influence of the phenotypic characteristics of the three variants on their relative proportions in mixed infections is discussed.