ARS | Publication request: Characterization of a cypovirus isolated from Missouri bilobed loopers

Submitted to: University of Missouri Life Sciences Week
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2012
Publication Date: April 18, 2012
Repository URL: http://bondlsc.missouri.edu/lsw/abstract_search/view/1405
Citation: Breitenbach, J.E., Popham, H.J. 2012. Characterization of a cypovirus isolated from Missouri bilobed loopers [abstract]. University of Missouri Life Sciences Week. Available: http://bondlsc.missouri.edu/lsw/abstract_search/view/1405.

Technical Abstract: Cypoviruses are non-enveloped arthropod-specific viruses of the family Reoviridae with a segmented, double-stranded RNA genome, and these viruses complete their replication cycle exclusively in the cellular cytoplasm by extruding mRNA and daughter genomes from conserved “turret” structures in their capsids. Cypovirus infection in most arthropod species results in a protracted replication and dissemination cycle, typically resulting in eventual host fatality. Field-isolated bilobed loopers (Autographa biloba) from Rolla, Missouri, were lethally infected with the baculovirus Anagrapha falcifera multicapsid nucleopolyhedrovirus (AfMNPV) and were also found to be co-infected with a novel cypovirus. Occlusion bodies containing both baculovirus and cypovirus particles were subsequently recovered from experimentally infected larvae. Liberation of the associated nucleic acids revealed a high molecular weight DNA band corresponding to the baculovirus genome and a ten-segmented dsRNA cypovirus genome. Further analysis revealed that the ten segments consisted of 0.5 to 4.5k base-pair bands, comprising a total genome size of approximately 22kb. Interestingly, co-infection of Heliothis virescens larvae with a mixture of the baculovirus and cypovirus did not result in extensive differences in mortality compared to infection with analogous preparations containing baculovirus alone. These data offer the first report of the natural co-infection of the bilobed looper pest insect by both a baculovirus and a cypovirus, and suggest the potential for such infections to be common in the subject geographical area. Complete genomic sequencing of this cypovirus and further studies on its interactions with baculoviruses will yield new insights into the pathogen-host interplay in the field and possibly new tools for use in crop protection strategies.