Mitochondrial pathway-mediated gut cell apoptosis: A key mechanism of nitenpyram toxicity in Diaphorina citri adults

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is a significant global pest of citrus that transmits Candidatus Liberibacter spp., the pathogen of Huanglongbing. Nitenpyram, a second-generation neonicotinoid insecticide, has shown substantial efficacy against several Hemiptera species, such as Nilaparvata lugens and Bemisia tabaci . It has also been employed for the control of D. citri . Nevertheless, its toxicity mechanism remains unclear. In this study, the toxicity of nitenpyram to adult D. citri was analyzed. RNA-Seq was conducted on adults exposed to LC 20 (12.86 μg/mL) and LC 50 (38.39 μg/mL) of nitenpyram. A total of 152 and 675 differentially expressed genes (DEGs) were identified in adults exposed to LC 20 and LC 50 of nitenpyram, respectively. KEGG enrichment analysis revealed that several DEGs were significantly enriched in the apoptosis pathway. TdT-mediated dUTP nick end labeling (TUNEL) staining further confirmed that LC 20 and LC 50 of nitenpyram induced apoptosis in the gut of adults. Moreover, elevated levels of reactive oxygen species (ROS) and reduced mitochondrial membrane potential (MMP) suggested that nitenpyram may initiate the mitochondrial apoptotic pathway in the adult gut. These results suggest that nitenpyram exposure generates toxicity via activating the mitochondrial pathway to trigger apoptosis in the adult guts of D. citri , providing valuable insights into the molecular toxicological mechanisms of nitenpyram in D. citri adults.