Heat‐responsive genes in Bemisia tabaci : roles in thermotolerance and neonicotinoid resistance

BACKGROUND: Temperature strongly influences insect physiology and can affect responses to chemical stress. However, the molecular basis underlying the relationship between thermal responses and insecticide resistance in the whitefly Bemisia tabaci remains poorly understood. This study aimed to identify conserved temperature-responsive genes and determine their functional roles in thermotolerance and neonicotinoid resistance. RESULTS: Comparative transcriptomic analyses of B. tabaci reared on cotton, soybean, and tomato identified 22 commonly up-regulated and seven commonly down-regulated genes under 32 °C compared with 25 °C. Nine shared temperature-responsive genes were selected for further analysis, and temporal expression profiling identified HSP70, HSP68, CYP6DW5, and CYP6A20 as prominent temperature-responsive candidates. RNA interference showed that silencing either HSP70 or HSP68 significantly increased mortality at 32 °C but had limited effects at 25 °C, supporting their roles in thermotolerance. In addition, silencing either CYP6DW5 or CYP6A20 significantly increased mortality following exposure to thiamethoxam, acetamiprid, and thiacloprid in the resistant population, but not in the susceptible population, demonstrating their contribution to neonicotinoid resistance. CONCLUSION: High temperature induces a conserved but functionally diverse transcriptional response in B. tabaci, with HSP70 and HSP68 contributing to thermotolerance and CYP6DW5 and CYP6A20 contributing to resistance against multiple neonicotinoids. These findings indicate that temperature-responsive genes can participate in distinct processes underlying thermal adaptation and insecticide resistance. Further investigation of the interaction between environmental temperature and resistance-associated pathways will improve our understanding of resistance phenotypes and may inform insecticide management under changing climatic conditions.