Functional analysis of AccCDK2-like and AccCINP-like genes in Apis cerana cerana under pesticide and heavy metal stress

Functional analysis of AccCPR in Apis cerana cerana under pesticide and heavy metal stress

NADPH-cytochrome P450 reductase (CPR) plays important roles in the metabolism of both endogenous and exogenous compounds through cytochrome P450, and is also involved in the detoxification of insecticides mediated by cytochrome P450. However, the CPR from Apis cerana cerana has not been well characterized and its function is still undescribed. This study isolated the CPR gene from Apis cerana cerana and investigated its functional role in the resistance to pesticide and heavy metal stress. Bioinformatic analysis revealed significant homology between the gene and its counterparts in other species. Functional investigations demonstrated diverse expression and localization patterns of this gene, with AccCPR primarily expressed in muscular tissues and the gut, suggesting its potential roles in flight activities and intestinal barrier function of bees. Furthermore, the expression levels of this gene were significantly modulated under pesticide and heavy metal stress. Notably, the overexpression of AccCPR led to a marked alteration the tolerance to external stressors in E. coli. Additionally, the silencing of the AccCPR gene resulted in a significant decrease in antioxidant enzyme activity and the expression levels of genes associated with antioxidant functions. Consequently, the mortality rate of Apis cerana cerana under imidacloprid stress was significantly elevated. Taken together, our findings suggest that AccCPR may play a pivotal role in the resistance of Apis cerana cerana to abiotic stresses such as pesticides and heavy metals by regulating antioxidant pathways.

Toxic effects of the heavy metal Cd on Apis cerana cerana (Hymenoptera: Apidae): Oxidative stress, immune disorders and disturbance of gut microbiota

Cadmium (Cd) is a toxic non-essential metal element that can enter the honey bee body through air, water and soil. Currently, there is a lack of sufficient research on the effects of Cd on A. cerana cerana, especially the potential risks of long-term exposure to sublethal concentrations. In order to ascertain the toxicological effects of the heavy metal Cd on bees, we performed laboratory-based toxicity experiments on worker bees and conducted analyses from three distinctive facets: antioxidative, immunological, and gut microbiota. The results showed that exposure of bees to high concentrations of Cd resulted in acute mortality, and the increase in mortality was concentration dependent. In long-term exposure to sublethal concentrations, Cd reduced the number of transcripts of antioxidant genes (AccSOD1, AccTPx3 and AccTPx4) and superoxide dismutase activity, causing an increase in malondialdehyde content. Simultaneously, the transcription of immune-related genes (AccAbaecin and AccApidaecin) and acetylcholinesterase activities was inhibited. Furthermore, Cd changes the structural characteristics of bacterial and fungal communities in the gut, disrupting the balance of microbial communities. In conclusion, the health and survival of honey bees are affected by Cd. This study provides a scientific basis for investigating the toxicological mechanisms and control strategies of the heavy metal Cd on honey bees, while facilitating a better understanding and protection of these valuable honey bees.