Advances in the Arms Race Between Silkworm and Baculovirus

Abstract

Insects are the largest group of animals. Nearly all organisms, including insects, have viral pathogens. An important domesticated economic insect is the silkworm moth Bombyx mori. B. mori nucleopolyhedrovirus (BmNPV) is a typical baculovirus and a primary silkworm pathogen. It causes major economic losses in sericulture. Baculoviruses are used in biological pest control and as a bioreactor. Silkworm and baculovirus comprise a well-established model of insect–virus interactions. Several recent studies have focused on this model and provided novel insights into viral infections and host defense. Here, we focus on baculovirus invasion, silkworm immune response, baculovirus evasion of host immunity, and enhancement of antiviral efficacy. We also discuss major issues remaining and future directions of research on silkworm antiviral immunity. Elucidation of the interaction between silkworm and baculovirus furnishes a theoretical basis for targeted pest control, enhanced pathogen resistance in economically important insects, and bioreactor improvement.

The Antiviral Molecule 5-Pyridoxolactone Identified Post BmNPV Infection of the Silkworm, Bombyx mori

“…Although multiple metabolic signaling pathways were enriched during BmNPV infection, ABC transporter, aminoacyl–transport RNA, and purine metabolism changed significantly at almost all infection stages. Among them, the ABC transporter pathway has been identified in multiple proteome and transcriptome studies [ 9 , 40 ]. In previous studies, knockout of the V-ATPase subunit gene BMgn016795A of the ABC transporter pathway resulted in a significant decrease in proliferation of BmNPV in BmE cells [ 8 ].…”

“…Bombyx mori nucleopolyhedrovirus (BmNPV) baculovirus is a major pathogen of the silkworm and causes serious economic losses [ 6 , 7 ]. Genetics and molecular biology studies have generated antiviral strains and revealed immunological responses [ 8 , 9 , 10 , 11 , 12 ]. However, the resistance mechanism remains unclear.…”

Sending Out Alarms: A Perspective on Intercellular Communications in Insect Antiviral Immune Response

“…The expression level of several pro-apoptotic genes, such as reaper, hid, and p53, increased in response to virus-induced stress, while anti-apoptotic genes, such as diap1 decreased, resulting in onset of apoptosis and subsequent phagocytosis of viral-infected cells by haemocytes (14)(15)(16)(17). Interestingly, sometimes this antiviral apoptosis is suppressed by host protein, as evidence found in silkworm that peptidoglycan recognition protein (PGRP) 2-2, inhibited baculovirus-induced apoptosis via Akt activation, reflecting arms race between insect and virus (18,19). Recently, a few studies found autophagy occurs after Drosophila infected with vesicular stomatitis virus (VSV), Rift Valley fever virus (RVFV) or Zika virus as evidenced by the elevation of lipidated Atg8 (Atg8-II) level and accumulation of Atg8 in autophagic punctae (20)(21)(22)(23)(24).…”

Haemocyte‐mediated immunity in insects: Cells, processes and associated components in the fight against pathogens and parasites

“…The antiviral mechanism of apoptosis can be suppressed by the virus, indicating an arms race between the insect and the virus. For example, all baculoviruses express antiapoptotic proteins, namely p35 or IAP, that interfere with caspase activity and block apoptosis in the host cells [218], and there are additional strategies to inhibit host antiviral apoptosis [219]. Drosophila C virus (DCV) is able to suppress the degradation of DIAP, thus inhibiting apoptosis and enhancing viral replication [220].…”