Abstract
Gut microbial communities can greatly affect host health by modulating the host's immune system. For many important insects, however, the relationship between the gut microbiota and immune function remains poorly understood. Here, we test whether the gut microbial symbionts of the honey bee can induce expression of antimicrobial peptides (AMPs), a crucial component of insect innate immunity. We find that bees up-regulate gene expression of the AMPs apidaecin and hymenoptaecin in gut tissue when the microbiota is present. Using targeted proteomics, we detected apidaecin in both the gut lumen and the haemolymph; higher apidaecin concentrations were found in bees harbouring the normal gut microbiota than in bees lacking gut microbiota. In in vitro assays, cultured strains of the microbiota showed variable susceptibility to honey bee AMPs, although many seem to possess elevated resistance compared to Escherichia coli. In some trials, colonization by normal gut symbionts resulted in improved survivorship following injection with E. coli. Our results show that the native, non-pathogenic gut flora induces immune responses in the bee host. Such responses might be a host mechanism to regulate the microbiota, and could potentially benefit host health by priming the immune system against future pathogenic infections.
Highlights
Bacterial communities living in symbiosis with animal hosts can be important factors in host health
When compared to bees lacking gut microbiota, bees inoculated with the normal gut microbiota via feeding with hive bee guts or with the gut symbiont S. alvi [3] had significant increases in transcripts for apidaecin, with an average 28.5-fold increase in the full microbiota-fed bees and an average 26.9-fold increase in S. alvi-fed bees in gut tissue
Neither of these genes showed significant expression differences between S. alvi-treated bees and bees lacking gut microbiota, they trend towards lower expression in the S. alvi treatment
Summary
Bacterial communities living in symbiosis with animal hosts can be important factors in host health. The recently characterized gut microbiota of the Western honey bee, Apis mellifera, comprises approximately nine socially transmitted bacterial species that probably have long evolutionary associations with their host [2,3,4,5]. This distinctive, specialized gut community is likely.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
