Study of coding genes and SNPs in the brain tissue genome of honeybee related to behavioral traits in Italian and African subspecies using RNA-Seq data analysis

Honeybees, as pollinating insects, are an important part of nature. Because behavioral traits are so important in honeybees, comparing brain tissue transcriptomes of the two subspecies with aggressive and calm behavioral characteristics makes it possible to understand this behavioral difference genetically. This study aimed to investigate to gene expression profile and identify the key genes in brain tissue in Italian (Apis Mellifera Ligustica) and African (Apis mellifera Scutellata) honeybees concerning behavioral traits. The Italian honeybee has calm behavioral characteristics, while the African is known as an aggressive honeybee.

RNA-Seq data were obtained from the NCBI  (GEO) database, and after pre-processing of reads, the brain tissue transcriptomes of both subspecies were aligned and mapped on the honey bee reference genome (v A.mel 4.5), and then data qualification, transcriptome assembly, differential expression analysis, and gene ontology were performed.

Differential gene expression analysis identified 16,701 genes on the honeybee reference genome, of which 22 genes in brain tissue between the two subspecies had significant differential expression (adj p-value <0 .05 and Log2FC>2). As well, some of these genes were first identified. Gene ontology analysis showed that among these 22 genes, such as ITPR, MRJP, HSP70Ab, MBS, GB45410, and Def1 are directly or indirectly involved in the occurrence of various traits such as defensive, health behavior, reproductive, heat, light, and smell sensitivity. In addition, the SNPs encoding the honeybee brain tissue genome were identified in both subspecies, and 99636 SNPs were identified in the Italian, and 92514 SNPs were identified in the African subspecies.

RNA-seq data, due to its high throughput, can provide us with accurate information about the expression of genes in different tissues in various subspecies. In this study, genes involved in honeybee behavioral traits and the SNPs in these genes were identified