ARS | Publication request: Classification, genetic variation, and biological activity of nucleopolyhedrovirus samples from larvae of the heliothine pests heliothis virescens, helicoverpa zea, and helicoverpa armigera

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 28, 2010
Publication Date: December 12, 2010
Citation: Rowley, D.L., Popham, H.J., Harrison, R.L. 2010. Classification, genetic variation, and biological activity of nucleopolyhedrovirus samples from larvae of the heliothine pests heliothis virescens, helicoverpa zea, and helicoverpa armigera. Meeting Abstract. 58:125.

Technical Abstract: A PCR-based method was used to classify 109 isolates of nucleopolyhedrovirus (NPV; Baculoviridae: Alphabaculovirus) collected worldwide from larvae of Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Partial nucleotide sequencing and phylogenetic analysis of three highly conserved genes (lef-8, lef-9, and polh) indicated that 83 of these isolates were variants of the H. zea-H. armigera single nucleopolyhedrovirus (Hz/HaSNPV) species group. Twenty of the isolates were variants of a previously sequenced but otherwise undescribed multiple NPV from H. armigera, HearMNPV. Four of the isolates were variants of Autographa californica MNPV (AcMNPV), and one isolate was a variant of Trichoplusia ni SNPV (TnSNPV). One sample from Colombia, South America, contained three distinct NPVs, including an AcMNPV variant, a HearMNPV variant, and a previously undescribed NPV that grouped with a clade containing TnSNPVand Chrysodeixis chalcites NPV. In bioassays of a selection of isolates against H. zea, the commercially available Gemstar isolate of HzSNPV killed larvae faster than other Hz/HaSNPV isolates, and Hz/HaSNPV isolates killed larvae faster than HearMNPV isolates. Gemstar and the HearMNPV isolates exhibited higher LC50s than the other Hz/HaSNPV isolates tested. These results indicate that viruses of the Hz/HaSNPV and HearMNPV species groups are major viral pathogens of heliothine pests worldwide.