Abstract: 【Aim】To explore the effects of gut microbiota deficiency on the brain neuronal cells of Apis mellifera, so as to provide data support for further research on the gut-brain axis information exchange mechanism of honeybee.【Methods】The brains from 20 10-day-old healthy worker adults of A. mellifera with sterile guts were pooled as the gut microbiota-depleted group (MF), and those from 20 10-day-old healthy worker adults of A. mellifera with normal gut microbiota were pooled as the conventional control group (CV). The 10×Genomics high-throughput single-cell transcriptome sequencing platform was used to complete single-cell capture, the captured single cells were sequenced by the standard process of snRNA-seq, and the single-cell transcriptome-level information for the MF and CV sample groups were obtained by principal component analysis (PCA) and unified manifold approximation and projection (UMAP) algorithms.【Results】Compared to CV, A. mellifera in MF showed no significant changes in the number and composition of nerve cell subtypes. However, the expression levels of genes in the brain neuronal cell subtypes in MF significantly changed, particularly those of genes associated with learning and memory in the neuronal cell subtypes, such as Hsp90, sGC-α1, Ecr, mGlutR1 and GluCl as compared to those in CV. Notably, Hsp90 was differentially expressed across all cell subtypes of the brain neurons. Additionally, the acetylcholine receptor genes nAChRα3, nAChRα6 and nAChRα7, and the glutamate transporter receptor gene Eaat-2 in the glial cell subtypes also exhibited differential expression.【Conclusion】The gut microbiota is essential for maintaining the normal function of neuronal cells in the brain of A. mellifera, and may primarily sustain nervous system function by regulating signal transduction between neurons of A. mellifera.

Key words: Apis mellifera, brain, neuron, single-cell transcriptome, gut microbes