The skin microbiome facilitates adaptive tetrodotoxin production in poisonous newts
The skin microbiome facilitates adaptive tetrodotoxin production in poisonous newts
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DOI：
10.7554/elife.53898
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发表时间：
2020-04-07
期刊：
影响因子：
7.7
通讯作者：
Eisthen, Heather L.
中科院分区：
文献类型：
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作者：
Vaelli, Patric M.;Theis, Kevin R.;Eisthen, Heather L.
糙皮蝾螈（Taricha granulosa）使用河豚毒素（TTX）阻断电压门控钠（Na-v）通道作为对捕食的化学防御。有趣的是，蝾螈在毒性方面表现出极端的种群水平变化，这归因于与TTX抗性捕食蛇的共同进化军备竞赛，但蝾螈中TTX的来源尚不清楚。在这里，我们调查是否共生细菌分离出有毒蝾螈可以产生TTX。我们的特点是皮肤相关的微生物群从一个有毒和无毒的蝾螈种群，并建立了纯培养物的分离细菌共生体从有毒蝾螈。然后，我们使用LC-MS/MS筛选细菌培养基中的TTX，并确定TTX产生的细菌菌株来自四个属，包括气单胞菌属，假单胞菌属，希瓦氏菌属和鞘氨醇。此外，我们对有毒蝾螈中的Na-v通道基因家族进行了测序，发现蝾螈表达具有修饰的TTX结合位点的Na-v通道，赋予对TTX的极端生理抗性。这项研究强调了适应性生理学，动物-细菌共生和生态环境之间的复杂相互作用。
Rough-skinned newts (Taricha granulosa) use tetrodotoxin (TTX) to block voltage-gated sodium (Na-v) channels as a chemical defense against predation. Interestingly, newts exhibit extreme population-level variation in toxicity attributed to a coevolutionary arms race with TTX-resistant predatory snakes, but the source of TTX in newts is unknown. Here, we investigated whether symbiotic bacteria isolated from toxic newts could produce TTX. We characterized the skin-associated microbiota from a toxic and non-toxic population of newts and established pure cultures of isolated bacterial symbionts from toxic newts. We then screened bacterial culture media for TTX using LC-MS/MS and identified TTX-producing bacterial strains from four genera, including Aeromonas, Pseudomonas, Shewanella, and Sphingopyxis. Additionally, we sequenced the Na-v channel gene family in toxic newts and found that newts expressed Na-v channels with modified TTX binding sites, conferring extreme physiological resistance to TTX. This study highlights the complex interactions among adaptive physiology, animal-bacterial symbiosis, and ecological context.