Molecular changes accompanying the loss in fertility of Spodoptera frugiperda female moths following infection with sub-lethal dose of baculovirus

Abstract

Sub-lethal baculoviral infections are associated with several developmental and reproductive defects but the mechanism behind these defects is not well understood. Here, we investigated the reproductive defects induced by sub-lethal infection of Spodoptera frugiperda nucleopolyhedrovirus (SfNPV) in Spodoptera frugiperda (J.E.Smith) adults. We observed significantly less oviposition, loss of fecundity and egg hatchability in surviving adults after SfNPV infection. Reciprocal crosses with both the genders suggested that the infection of either sex could result in the fertility defects. An investigation of anatomy of reproductive of the surviving females suggested minor defects but confirmed reduced mating with infected males. Oviposition defects were observed in the infected group in spite of successful mating. Differential transcriptome analysis of infertile females from sub-lethally infected group revealed alteration of reproductive, developmental and behavioural pathway genes in comparison to control. We have also investigated the involvement of hormonal genes and piRNAs in their contribution to reproductive defects post sub-lethal baculoviral infection. This study will shed some light on the molecular mechanisms behind the sub-lethal effects observed in the surviving adults post baculovirus infection and will be useful to understand the infertility pathways in insects.