Gut bacteria of the silkworm Bombyx mori facilitate host resistance against the toxic effects of organophosphate insecticides
Gut bacteria of the silkworm Bombyx mori facilitate host resistance against the toxic effects of organophosphate insecticides
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DOI：
10.1016/j.envint.2020.105886
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发表时间：
2020-10-01
影响因子：
11.8
通讯作者：
Shao, Yongqi
中科院分区：
文献类型：
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作者：
Chen, Bosheng;Zhang, Nan;Shao, Yongqi
有机磷杀虫剂在农业中大量用于害虫控制，在世界范围内引起了日益严重的环境问题和公众健康问题。具有讽刺意味的是，杀虫剂抗性在主要鳞翅目害虫中迅速发展，部分是通过它们的微生物共生体。为了研究微生物群赋予鳞翅目昆虫杀虫剂抗性的可能机制，给模式生物家蚕（鳞翅目：家蚕科）喂食不同的抗生素以诱导肠道生态失调（微生物群失衡）。用多粘菌素处理的幼虫在暴露于毒死蜱时，存活率显着降低。通过高通量测序，我们发现寡养单胞菌属和肠球菌属的丰度。治疗后发生了很大变化。为了评估这两组细菌在毒死蜱抗性中所起的作用，建立了无菌（GF）养蚕方案，以避免自然微生物群和抗生素的影响。单协会的GF蚕与寡养单胞菌增强宿主对毒死蜱的抗性，但不是在肠球菌喂养的幼虫，符合幼虫解毒活性。粪样中毒死蜱残留的GC-mu ECD检测结果表明，无论是寡养单胞菌还是肠球菌都不能直接在肠道内降解毒死蜱。然而，肠道代谢组学分析揭示了一个高度种属特异性的模式，与高水平的必需氨基酸产生的家蚕幼虫肠道monoassociated与寡养单胞菌。这种关键的营养供应显着增加主机健身，从而使幼虫规避这些有毒化学品的有害影响更有效。总之，我们的研究不仅提出了一种新的机制，在臭名昭著的鳞翅目害虫杀虫剂抗性，但也提供了一个有用的模板，调查宿主和肠道细菌之间的相互作用，在复杂的环境系统。
Organophosphate insecticides that are heavily used in agriculture for pest control have caused growing environmental problems and public health concerns worldwide. Ironically, insecticide resistance develops quickly in major lepidopteran pests, partially via their microbial symbionts. To investigate the possible mechanisms by which the microbiota confers insecticide resistance to Lepidoptera, the model organism silkworm Bombyx mori (Lepidoptera: Bombycidae) was fed different antibiotics to induce gut dysbiosis (microbiota imbalance). Larvae treated with polymyxin showed a significantly lower survival rate when exposed to chlorpyrifos. Through highthroughput sequencing, we found that the abundances of Stenotrophomonas and Enterococcus spp. changed substantially after treatment. To assess the roles played by these two groups of bacteria in chlorpyrifos resistance, a germ-free (GF) silkworm rearing protocol was established to avoid the influence of natural microbiota and antibiotics. Monoassociation of GF silkworms with Stenotrophomonas enhanced host resistance to chlorpyrifos, but not in Enterococcus-fed larvae, consistent with larval detoxification activity. GC-mu ECD detection of chlorpyrifos residues in feces indicated that neither Stenotrophomonas nor Enterococcus degraded chlorpyrifos directly in the gut. However, gut metabolomics analysis revealed a highly species-specific pattern, with higher levels of essential amino acid produced in the gut of silkworm larvae monoassociated with Stenotrophomonas. This critical nutrient provisioning significantly increased host fitness and thereby allowed larvae to circumvent the deleterious effects of these toxic chemicals more efficiently. Altogether, our study not only suggests a new mechanism for insecticide resistance in notorious lepidopteran pests but also provides a useful template for investigating the interplay between host and gut bacteria in complex environmental systems.