Comparison of the gut microbiome of sacbrood virus-resistant and -susceptible Apis cerana from South Korea

Abstract

Honey bees are important pollinators for the conservation of the ecosystem and agricultural products and provide a variety of products important for human use, such as honey, pollen, and royal jelly. Sacbrood disease (SD) is a devastating viral disease in Apis cerana; an effective preventive measure for SD is urgently needed. In this study, the relationship between the gut microbiome of honey bees and SD was investigated by pyrosequencing. Results revealed that sacbrood virus (SBV)-resistant A. cerana strains harbour a unique acetic acid bacterium, Bombella intestini, and the lactic acid bacteria (LAB) Lactobacillus (unclassified)_uc, Bifidobacterium longum, B. catenulatum, Lactococcus lactis, and Leuconostoc mesenteroides in larvae and Hafnia alvei, B. indicum, and the LAB L. mellifer and Lactobacillus HM215046_s in adult bees. Changes in the gut microbiome due to SBV infection resulted in loss of bacteria that could affect host nutrients and inhibit honey bee pathogens, such as Gilliamella JFON_s, Gilliamella_uc, Pseudomonas putida, and L. kunkeei in A. cerana larvae and Frischella_uc, Pantoea agglomerans, Snodgrassella_uc, and B. asteroides in adult bees. These findings provide important information for the selection of probiotics for A. cerana larvae and adults to prevent pathogenic infections and keep honey bees healthy.

The Gut Microbiota at Different Developmental Stages of Apis cerana Reveals Potential Probiotic Bacteria for Improving Honeybee Health

“…Further characterization showed that larvae and pupae have a few core bacteria in their gut. This was consistent with previous reports showing that the core bacteria are relatively rare in larvae; however, they consist of highly variable communities dominated by non-core environmental bacteria [ 6 , 28 ]. Indeed, in this study, the microbiota of larvae was predominant by L. kunkeei , M. plutonius , Lactobacillus_uc , Commensalibacter, whereas those in pupae were B. subtilis , S. pruni , Lachnospiraceae .…”

“…Adult workers have a relatively diverse set of bacteria in their gut compared with larvae and pupae. The gut microbiota of A. cerana adult workers consisted of nine bacterial species, which was consistent with our recent studies on the gut microbiota of Vietnamese A. cerana [ 16 ] and the previous reports that the gut microflora of workers ( A. melifera and A. cerana ) may contain from five to nine taxa belonging to four phyla, including Firmicutes , Actinobacteria , Proteobacteria , and Bacteroidetes [ 1 , 2 , 12 , 16 , 17 , 18 , 28 ]. However, the composition and the abundance of predominant bacteria groups varied due to geographical differences and natural conditions.…”

“…[ 29 , 33 ] due to antibacterial activity via the production of antimicrobial peptides or protein [ 29 ]. It has been found that L. kunkeei significantly decreased when compared to the gut microbiota of healthy and SD-affected larvae in SBV-susceptible A. cerana [ 28 ]. B. subtilis was one of the most important probiotic Bacillus species for humans and animals since they have a broad range of antioxidant and antimicrobial activities (such as surfactin, bacteriocins, bacteriocin-like inhibitory substances (BLISes), etc.)…”

“…Interestingly, an endosymbiotic acetic acid bacterium in bumble bees, Bombella intestine, was also detected with an adequate amount (7%) in the larvae since this species was first identified in A. cerana in Korea by Yun et al (2022) [ 28 ]. These bacteria can increase larval survival against pathogens by the secretion of acids [ 37 ].…”

“…These bacteria can increase larval survival against pathogens by the secretion of acids [ 37 ]. It has been reported that B. intestini and Lactobacillus_uc were only detected in sacbrood virus-resistant A. cerana, whereas they were not included in SBV-susceptible A. cerana larva [ 28 ].…”