School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China.
School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China.
Ecotoxicol Environ Saf. 2022 Aug;241:113763. doi: 10.1016/j.ecoenv.2022.113763. Epub 2022 Jun 11.
The immunotoxicity induced by heavy metals on herbivorous insects reflect the alterations of the susceptibility to entomopathogenic agents in herbivorous insects exposed to heavy metal. In the present study, the susceptibility of gypsy moth larvae to Bacillus thuringiensis under Cd treatment at low and high dosages was investigated, and the gut microbiome-hemolymph metabolome responses that affected larval disease susceptibility caused by Cd exposure were examined. Our results showed that mortality of gypsy moth larvae caused by B. thuringiensis was significantly higher in larvae pre-exposed to Cd stress, and there was a synergistic effect between Cd pre-exposure and bacterial infection. Exposure to Cd significantly decreased the abundance of several probiotics (e.g., Serratia for the low Cd dosage and Weissella, Aeroonas, and Serratia for the high Cd dosage) and increased the abundances of several pathogenic bacteria (e.g., Stenotrophomonas, Gardnerella, and Cutibacterium for the low Cd dosage and Pluralibacter and Tsukamurella for the high Cd dosage) compared to the controls. Moreover, metabolomics analysis indicated that amino acid biosynthesis and metabolism were significantly perturbed in larval hemolymph under Cd exposure at both the low and high dosages. Correlation analysis demonstrated that several altered metabolites in larval hemolymph were significantly correlated with changes in the gut microbial community. The results demonstrate that prior exposure to Cd increases the susceptibility of gypsy moth larvae to B. thuringiensis in a synergistic fashion due to gut microbiota dysbiosis and hemolymph metabolic disorder, and thus microbial-based biological control may be the best pest control strategy in heavy metal-polluted areas.
重金属对植食性昆虫的免疫毒性反映了暴露于重金属的植食性昆虫对昆虫病原物敏感性的改变。本研究调查了 Cd 低、高剂量处理下舞毒蛾幼虫对苏云金芽孢杆菌的敏感性，并研究了影响 Cd 暴露引起幼虫疾病易感性的肠道微生物组-血淋巴代谢组反应。研究结果表明，Cd 应激预暴露的幼虫中 B. thuringiensis 引起的舞毒蛾幼虫死亡率明显更高，且 Cd 预暴露与细菌感染之间存在协同作用。与对照组相比，Cd 暴露显著降低了几种益生菌（例如低 Cd 剂量下的 Serratia 和高 Cd 剂量下的 Weissella、Aeroonas 和 Serratia）的丰度，并增加了几种病原菌（例如低 Cd 剂量下的 Stenotrophomonas、Gardnerella 和 Cutibacterium 和高 Cd 剂量下的 Pluralibacter 和 Tsukamurella）的丰度。此外，代谢组学分析表明，低、高 Cd 剂量暴露下幼虫血淋巴中的氨基酸生物合成和代谢明显受到干扰。相关性分析表明，幼虫血淋巴中几种改变的代谢物与肠道微生物群落的变化显著相关。结果表明，由于肠道微生物群落失调和血淋巴代谢紊乱，Cd 预暴露以协同方式增加了舞毒蛾幼虫对 B. thuringiensis 的敏感性，因此基于微生物的生物防治可能是重金属污染地区的最佳害虫防治策略。
