Impact of Sacbrood Virus on Larval Microbiome of Apis mellifera and Apis cerana.

Rujipas Yongsawas,Panuwan Chantawannakul,Terd Disayathanoowat,Jeffery S Pettis,Ammarin In-On,Veeranan Chaimanee,Dawn Lopez,Humberto Freire Boncristiani Junior

doi:10.3390/insects11070439

Abstract

In this study, we examined the impact of Sacbrood virus (SBV), the cause of larval honeybee (Apis mellifera) death, producing a liquefied a larva sac, on the gut bacterial communities on two larval honeybee species, Apis mellifera and Apis cerana. SBV was added into a worker jelly food mixture and bee larvae were grafted into each of the treatment groups for 24 h before DNA/RNA extraction. Confirmation of SBV infection was achieved using quantitative reverse transcription polymerase chain reaction (RT-qPCR) and visual symptomology. The 16S rDNA was sequenced by Illumina sequencing. The results showed the larvae were infected with SBV. The gut communities of infected A. cerana larvae exhibited a dramatic change compared with A. mellifera. In A. mellifera larvae, the Illumina sequencing revealed the proportion of Gilliamella, Snodgrassella and Fructobacillus was not significantly different, whereas in A. cerana, Gilliamella was significantly decreased (from 35.54% to 2.96%), however, with significant increase in Snodgrassella and Fructobacillus. The possibility of cross-infection should be further investigated.

Highlights

The Western cavity nesting bee Apis mellifera and Asiatic cavity nesting bee Apis cerana are two domesticated bee species in worldwide apiculture [1,2]
The results reveal an overwhelming change in the bacterial microbiota in both species of honeybee larvae, A. mellifera and A. cerana, during viral infection, which has not been previously shown and has potential applications in apiculture worldwide
We investigated the interaction between viral infection and the larval microbiome using an NGS technique to compare the difference in gut microbial communities between control larvae and Sacbrood virus (SBV)-infected larvae, in two different species of honeybee, A. mellifera and A. cerana

Summary

Introduction

The Western cavity nesting bee Apis mellifera and Asiatic cavity nesting bee Apis cerana are two domesticated bee species in worldwide apiculture [1,2]. The virus infects bee larvae, causing the larval development process to fail, leading to eventual death [5]. SBV infection can be found in both A. mellifera and A. cerana [10,11,12,13], while the infection in A. cerana is more severe, in terms of prevalence and colony damage, than A. mellifera [14]. The consequences of this infection in A. cerana have been reported in Thailand, Vietnam, China, India and South Korea [5,15,16,17,18]

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Conclusion