Microscopic investigation of AcMNPV infection in the Trichoplusia ni midgut
Citation
Javed, M.A., Harris, S., Willis, L.G., Theilmann, D.A., Donly, B.C., Erlandson, M.A., Hegedus, D.D. (2016). Microscopic investigation of AcMNPV infection in the Trichoplusia ni midgut. Journal of Invertebrate Pathology, [online] 141 24-33. http://dx.doi.org/10.1016/j.jip.2016.10.006
Plain language summary
In nature, infection with the insect specific baculovirus isolate, AcMNPV, begins with ingestion of viral occlusion bodies (OBs) from which occlusion-derived viruses (ODV) are released in the gut lumen and go on to infect midgut cells. This study explored the early stages of cabbage looper midgut infection using recombinant viruses expressing green fluorescent protein (GFP) and/or a VP39-mCherry fusion protein under the control of early and late promoters, respectively. The insect host anterior midgut region was identified as the predominant site for primary infection. Infection of midguts revealed that active viral replication and cell-to-cell spread was required for the formation of infection foci and the subsequent spread to uninfected midgut cells and then other cells in the blood system of the insect. The spread of the infection from primary infected cells to secondary cells within the midgut was shown to be dependent upon a virus gene product known as the membrane fusion protein or GP64.
Abstract
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is the type species for the genus Alphabaculovirus in the family Baculoviridae. In nature, AcMNPV infection begins with ingestion of viral occlusion bodies (OBs) from which occlusion-derived viruses (ODV) are released to infect midgut cells. This study explored the early stages of Trichoplusia ni midgut infection using recombinant viruses expressing green fluorescent protein (GFP) and/or a VP39-mCherry fusion protein under the control of early and late promoters, respectively. Using a recombinant ie1:GFP virus, the anterior midgut region was identified as the predominant site for primary infection. Infection of midguts using the GFP-VP39mCherry-dual labelled recombinant virus revealed that active viral replication and cell-to-cell spread was required for the formation of infection foci and the subsequent spread to uninfected midgut cells and tracheoblasts. The spread of the infection from primary infected cells to secondary cells within the midgut was shown to be dependent upon the membrane fusion protein GP64.