The Transcriptomic Landscape of Molecular Effects after Sublethal Exposure to Dinotefuran on Apis mellifera

SIMPLE SUMMARY: Apis mellifera is one of the most important pollinator communities in nature. Insecticide residues in pollen and nectar, due to their wide use, may harm bees. Thus, it is crucial to provide novel insights into the effects of neonicotinoid insecticides on pollinators for protecting bees and maintaining a long-term stable ecological environment. The aim of our study was to investigate the effect and the mechanisms underlying bees impaired by dinotefuran. In the present study, for the first time, we found the mRNA expression profile of bees changes after treatment with sublethal doses of dinotefuran. Overall, our findings enhance understanding of the molecular mechanisms that underly physiological and behavioural damage for bees after dinotefuran exposure. ABSTRACT: The decreasing number of bees is a global ecological problem. With the advancement of agricultural modernisation, the large-scale use of neonicotinoid insecticides is one of the main factors leading to the decline of bees. The aim of the present study was to investigate the effect and the mechanisms underlying bees impaired by dinotefuran. Acute (48 h) oral toxicity tests showed that a 5% lethal concentration (LC(5)) was 0.220 mg/L, and a 20% lethal concentration (LC(20)) was 0.458 mg/L. The gene expression profile shows that when compared with the control group, the LC(5) group induced 206 significantly upregulated, differentially expressed genes (DEGs) and 363 significantly downregulated DEGs, while the LC(20) group induced 180 significantly upregulated DEGs and 419 significantly downregulated DEGs. Significantly, transcriptomic analysis revealed DEGs involved in immunity, detoxification, and the nervous system, such as antimicrobial peptides, vitellogenin, synaptotagmin-10, AChE-2, and nAChRa9. Furthermore, Gene Ontology (GO) annotation and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis revealed that DEGs were enriched in amino acid and fatty acid biosynthesis and metabolism pathways. Collectively, our findings will help clarify the deleterious physiological and behavioural impacts of dinotefuran on bees and provide a basis for future research on the mechanisms underlying bees impaired by dinotefuran.