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Location: Biological Control of Insects Research
Title: Determination and analysis of the genome sequence of Spodoptera littoralis multiple nucleopolyhedrovirus
Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 26, 2012
Publication Date: January 24, 2013
Citation: Breitenbach, J.E., El-Sheikh, E.A., Harrison, R.L., Rowley, D.L., Sparks, M., Gundersen, D.E., Popham, H.J. 2013. Determination and analysis of the genome sequence of Spodoptera littoralis multiple nucleopolyhedrovirus. Virus Research. 171(1):194-2008.
Interpretive Summary: Insect pests cause billions of dollars of damage to crops each year. The use of chemical insecticides to control insect pests can have negative ecological, environmental, and health consequences. Baculoviruses are a group of insect viruses used for biologically-based insect control without the problems of chemical insecticides. However, the success of baculoviruses as control agents is partially limited by their slow speed of action against insect pests. A more complete understanding of the genetic factors controlling baculovirus insecticidal activity and speed of kill is necessary for improving their scope and performance as biopesticides. In this study, a baculovirus originally isolated from Egyptian cotton leaf worm was examined. The entire DNA sequence of this virus was determined and compared to the previously sequenced fall armyworm baculovirus. Additionally the virus was found to control fall armyworm larvae in laboratory tests. The information in this study provides clues for the development of baculovirus strains with potential to control targeted pests worldwide. Baculoviruses have a wide range of applications in addition to their use as biopesticides, and this study will be of interest to scientists in academia, government, and industry who work with this group of viruses.
The Spodoptera littoralis multiple nucleopolyhedrovirus (SpliMNPV), a pathogen of the Egyptian cotton leaf worm Spodoptera littoralis, was subjected to sequencing of its entire DNA genome and bioassay analysis comparing its virulence to that of other baculoviruses. The annotated SpliMNPV genome of 137,998 bp was found to harbor 132 open reading frames and 15 homologous repeat regions. Four unique genes not present in SpltMNPV were identified, as were 14 genes that were absent or translocated by comparison. Bioassay analysis of experimentally infected Spodoptera frugiperda revealed an extended killing time for SpliMNPV as compared to S. frugiperda MNPV (SfMNPV), but a level of mortality similar to that caused by infection with SfMNPV and superior to that of Autographa californica MNPV (AcMNPV). Although extensive similarity was observed between the genome structure and predicted translation products of SpliMNPV and Spodoptera litura MNPV (SpltMNPV), genetic distances between isolates of SpliMNPV and SpltMNPV suggest that they are in fact different species of genus Alphabaculovirus.