PRJNA484772
Global analysis of baculovirus Autographa californica Multiple Nucleopolyhedrovirus (AcMNPV) gene expression in the midgut of the Trichoplusia ni larvae
The baculovirus AcMNPV is a large dsDNA virus that encodes approximately 156 genes and is highly pathogenic to a variety of larval lepidopteran insects in nature. Oral infection of larval midgut cells is initiated by the occlusion derived virus (ODV), while secondary infection of other tissues is mediated by the budded virus (BV). Global viral gene expression has been studied in detail in BV-infected cell cultures, but studies of ODV-infection in the larval midgut are limited. In this study, we examined expression of the ~156 AcMNPV genes in Trichoplusia ni midgut tissue using a transcriptomic approach. We analyzed expression profiles of viral genes in the midgut, and compared them with profiles from a T. ni cell line (Tnms42). Several viral genes (p6.9, orf76, orf75, pp31, Ac-bro, odv-e25, and odv-ec27) had high expression levels in the midgut throughout the infection. Also, the expression of genes associated with occlusion bodies (polh and p10) appeared to be delayed in the midgut in comparison with the cell line. Comparisons of overall viral gene expression profiles revealed remarkable similarities between the midgut and cell line for most genes, although substantial differences were also observed for some viral genes. These included genes associated with high level BV production (fp-25k), acceleration of systemic infection (v-fgf), and enhancement of viral movement (arif-1/orf20). These differential expression patterns appear to represent specific adaptations for virus infection and movement through the polarized cells of the lepidopteran midgut.