The Gut Microbiota Can Provide Viral Tolerance in the Honey Bee.

Anja Tehel,Tabea Streicher,Anja Manigk,Christopher Dosch,Robert J. Paxton,Simon Tragust

doi:10.3390/microorganisms9040871

Anja Tehel, Tabea Streicher + Show 4 more

Open Access

https://doi.org/10.3390/microorganisms9040871

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Journal: Microorganisms	Publication Date: Apr 17, 2021
Citations: 42	License type: CC BY 4.0

Affiliation: Martin Luther University Halle-Wittenberg

Abstract

Adult honey bees host a remarkably consistent gut microbial community that is thought to benefit host health and provide protection against parasites and pathogens. Currently, however, we lack experimental evidence for the causal role of the gut microbiota in protecting the Western honey bees (Apis mellifera) against their viral pathogens. Here we set out to fill this knowledge gap by investigating how the gut microbiota modulates the virulence of a major honey bee viral pathogen, deformed wing virus (DWV). We found that, upon oral virus exposure, honey bee survival was significantly increased in bees with an experimentally established normal gut microbiota compared to control bees with a perturbed (dysbiotic) gut microbiota. Interestingly, viral titers were similar in bees with normal gut microbiota and dysbiotic bees, pointing to higher viral tolerance in bees with normal gut microbiota. Taken together, our results provide evidence for a positive role of the gut microbiota for honey bee fitness upon viral infection. We hypothesize that environmental stressors altering honey bee gut microbiota composition, e.g., antibiotics in beekeeping or pesticides in modern agriculture, could interact synergistically with pathogens, leading to negative effects on honey bee health and the epidemiology and impact of their viruses.

Highlights

Gut-associated microbial communities are ubiquitous in animals, and their presence can affect important host traits [1,2]
Overwintering honey bee colony losses have been linked to the presence of the exotic invasive ectoparasitic mite Varroa destructor and the viruses it transmits [13,14,15,16], deformed wing virus (DWV) [15], which has become panzootic in honey bee populations where V. destructor has been introduced [16,17,18,19]
Experimental prevention of gut microbiota establishment in microbiota− bees led to bees that had a significantly lower abundance of gut bacteria and specific honey bee gut microbiota members compared to both experimental microbiota+ bees and hive bees form source colonies (Figure 1; Table S3)

Summary

Introduction

Gut-associated microbial communities are ubiquitous in animals, and their presence can affect important host traits [1,2]. Social bees are no exception, featuring a recurring set of bacterial species clusters (phylotypes) in their gut [3]. In the eusocial Western honey bee (Apis mellifera), the gut microbiota is dominated by up to nine bacterial phylotypes [4,5], which are acquired by adult honey bees after emergence through contact with nest material and nestmates [6,7]. Several studies (reviewed in [8,9,10]) have shown that the presence of the characteristic, normal honey bee gut microbiota, either in its entirety or of single members, is related to bee health and physiology and likely plays a role in protection against a range of parasites and pathogens. The two widespread genotypes of DWV, genotypes A and B, are both highly virulent pathogens of A. mellifera when transmitted by V. destructor or experimentally by injection [20], though DWV is readily transmitted orally [17]

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