Transcriptome Profiling Reveals a Novel Mechanism of Antiviral Immunity Upon Sacbrood Virus Infection in Honey Bee Larvae (Apis cerana)

Abstract

The honey bee is one of the most important pollinators in the agricultural system and is responsible for pollinating a third of all food we eat. Sacbrood virus (SBV) is a member of the virus family Iflaviridae and affects honey bee larvae and causes particularly devastating disease in the Asian honey bees, Apis cerana. Chinese Sacbrood virus (CSBV) is a geographic strain of SBV identified in China and has resulted in mass death of honey bees in China in recent years. However, the molecular mechanism underlying SBV infection in the Asian honey bee has remained unelucidated. In this present study, we employed high throughput next-generation sequencing technology to study the host transcriptional responses to CSBV infection in A. cerana larvae, and were able to identify genome-wide differentially expressed genes associated with the viral infection. Our study identified 2,534 differentially expressed genes (DEGs) involved in host innate immunity including Toll and immune deficiency (IMD) pathways, RNA interference (RNAi) pathway, endocytosis, etc. Notably, the expression of genes encoding antimicrobial peptides (abaecin, apidaecin, hymenoptaecin, and defensin) and core components of RNAi such as Dicer-like and Ago2 were found to be significantly upregulated in CSBV infected larvae. Most importantly, the expression of Sirtuin target genes, a family of signaling proteins involved in metabolic regulation, apoptosis, and intracellular signaling was found to be changed, providing the first evidence of the involvement of Sirtuin signaling pathway in insects’ immune response to a virus infection. The results obtained from this study provide novel insights into the molecular mechanism and immune responses involved in CSBV infection, which in turn will contribute to the development of diagnostics and treatment for the diseases in honey bees.

Stably transmitted defined microbial community in honeybees preserves Hafnia alvei inhibition by regulating the immune system

“…The colonization resistance conferred by the gut microbiota through stimulating the host’s innate immune system was supported by increasing evidence ( Lawley and Walker, 2013 ). The innate immune system of honeybees comprises the Toll and Imd pathways ( Lourenço et al, 2013 , 2018 ; Danihlík et al, 2015 ), which primarily regulate the production of antimicrobial peptides (AMPs), such as abaecin, apidaecin, defensin, and hymenoptaecin, during pathogen infection ( Evans et al, 2006 ; Guo et al, 2021 ). When honeybees were colonized with conventional gut microbiota or mono-colonized with strains from S. alvi , the immune system of honeybees was stimulated to inhibit potential pathogens such as Serratia marcescens ( Horak et al, 2020 ).…”

Specific Strains of Honeybee Gut Lactobacillus Stimulate Host Immune System to Protect against Pathogenic Hafnia alvei

“…The indirect immune regulation of honeybees and other insects in response to gut commensals consists of three levels of resistance: physical barriers, cell-mediated immunity, and cell-free humoral immunity ( 20 ). Induction of honeybee innate immune responses by the gut microbes have been proposed, while only several bee gut members have been tested, such as Snodgrassella alvi ( 21 ), Lactobacillus kunkeei ( 23 ), and Frischella perrara ( 42 ).…”

“…Honeybee antibacterial immunity relies on the Toll and Imd pathways, which primarily regulate the production of AMPs released into circulation under the activation of the two signal pathways during pathogen infection ( 19 ). In honeybee, four families of AMPs—abaecin, apidaecin, defensin, and hymenoptaecin—have been recognized, which are key components of the innate immune system of honeybee ( 20 ). So far, several studies have shown that the gut microbiota can influence bee health by the modulation of host immune responses.…”

Біологічна ефективність колоїдного (нанорозмірного) діоксиду церію у бджіл Apis mellifera

“…Зважаючи на те, що у Apis mellifera відсутній адаптивний імунітет [30], основні складники їх антиінфекційного захисту -вивільнення антимікробних пептидів, фагоцитоз, меланізація та ферментативне руйнування патогенів [31,32]. У відповідь на інфікування ВМР у бджіл також активується РНК-інтерференція [33,34]. Зважаючи на дані [35] щодо мінімальної віруліцидної дії нано-СеО2 проти вірусів, які не мають суперкапсиду, а ВМР належить до їх числа, антивірусна ефективність нано-СеО2 може бути пов'язана саме із впливом на неспецифічну ланку антиінфекційного захисту.…”