National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou, PR China.
National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou, PR China.
Ecotoxicol Environ Saf. 2023 Oct 1;264:115383. doi: 10.1016/j.ecoenv.2023.115383. Epub 2023 Aug 25.
Bacterial symbionts exhibiting co-evolutionary patterns with insect hosts play a vital role in the nutrient synthesis, metabolism, development, reproduction, and immunity of insects. The brown planthopper (BPH) has a strong ability to adapt to various environmental stresses and can develop resistance to broad-spectrum insecticides. We aimed to investigate whether gut symbionts of BPH play a major role in the detoxification of insecticides and host fitness in unfavorable environments. Nicotine-treated rice plants were exposed to BPH (early stage) and the gut microbiome of the emerging female adults were analyzed using high throughput sequencing (HTS). Nicotine administration altered the diversity and community structure of BPH symbionts with significant increases in bacterial members such as Microbacteriaceae, Comamondaceae, Enterobacteriaceae, and these changes may be associated with host survival strategies in adverse environments. Furthermore, the in-vitro study showed that four intestinal bacterial strains of BPH (Enterobacter NLB1, Bacillus cereus NL1, Ralstonia NLG26, and Delftia NLG11) could degrade nicotine when grown in a nicotine-containing medium, with the highest degradation (71%) observed in Delftia NLG11. RT-qPCR and ELISA analysis revealed an increased expression level of CYP6AY1 and P450 enzyme activities in Delftia NLG11, respectively. CYP6AY1 increased by 20% under the action of Delftia and nicotine, while P450 enzyme activity increased by 18.1%. After CYP6AY1 interference, nicotine tolerance decreased, and the mortality rate reached 76.65% on the first day and 100% on the third day. Moreover, Delftia NLG11 helped axenic BPHs to increase their survival rate when fed nicotine in the liquid-diet sac (LDS) feeding system. Compared with axenic BPHs, the survival rate improved by 25.11% on day 2% and 6.67% on day 3. These results revealed an altered gut microbiota and a cooperative relationship between Delftia NLG11 and CYP6AY1 in nicotine-treated BPH, suggesting that insects can adapt to a hostile environment by interacting with their symbionts and providing a new idea for integrated pest management strategies.
与昆虫宿主表现出共同进化模式的细菌共生体在昆虫的营养合成、代谢、发育、繁殖和免疫中起着至关重要的作用。褐飞虱具有很强的适应各种环境压力的能力，并能对广谱杀虫剂产生抗性。我们旨在研究褐飞虱的肠道共生体是否在杀虫剂解毒和不利环境中宿主适应性方面发挥主要作用。将尼古丁处理过的水稻植株暴露于褐飞虱（早期），并用高通量测序（HTS）分析新出现的雌性成虫的肠道微生物组。尼古丁处理改变了褐飞虱共生体的多样性和群落结构，细菌成员如 Microbacteriaceae、Comamondaceae 和 Enterobacteriaceae 的丰度显著增加，这些变化可能与宿主在不利环境中的生存策略有关。此外，体外研究表明，褐飞虱的四种肠道细菌菌株（Enterobacter NLB1、Bacillus cereus NL1、Ralstonia NLG26 和 Delftia NLG11）可以在含有尼古丁的培养基中降解尼古丁，其中 Delftia NLG11 的降解率最高（71%）。RT-qPCR 和 ELISA 分析分别显示 Delftia NLG11 中 CYP6AY1 的表达水平和 P450 酶活性增加。在 Delftia 和尼古丁的作用下，CYP6AY1 增加了 20%，而 P450 酶活性增加了 18.1%。CYP6AY1 干扰后，尼古丁耐受性降低，第 1 天死亡率达到 76.65%，第 3 天达到 100%。此外，在液体饮食囊（LDS）喂养系统中给褐飞虱喂食尼古丁时，Delftia NLG11 有助于无菌褐飞虱提高其存活率。与无菌褐飞虱相比，第 2 天的存活率提高了 25.11%，第 3 天提高了 6.67%。这些结果揭示了在尼古丁处理的褐飞虱中肠道微生物组的改变和 Delftia NLG11 与 CYP6AY1 之间的协同关系，表明昆虫可以通过与共生体相互作用来适应恶劣环境，并为综合虫害管理策略提供了新的思路。
