Unique metabolites protect earthworms against plant polyphenols.
Unique metabolites protect earthworms against plant polyphenols.
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DOI：
10.1038/ncomms8869
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发表时间：
2015-08-04
影响因子：
16.6
通讯作者：
Bundy JG
中科院分区：
文献类型：
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作者：
Liebeke M;Strittmatter N;Fearn S;Morgan AJ;Kille P;Fuchser J;Wallis D;Palchykov V;Robertson J;Lahive E;Spurgeon DJ;McPhail D;Takáts Z;Bundy JG
所有高等植物都会产生多酚，以抵御地上食草动物。这些多酚也会影响分解植物落叶的土壤微型和大型动物群落。因此，多酚间接影响土壤养分的流动，并最终影响土壤中的碳周转和生态系统功能。蚯蚓是许多土壤中动物生物量的主要组成部分，目前尚不清楚它们如何应对富含多酚的食物。在此，我们发现蚯蚓肠道中拥有一类独特的表面活性代谢物，我们将其命名为“蚯蚓防御素”。这些化合物抵消了多酚对蚯蚓肠道酶的抑制作用，并且在实验室和野外种群中，富含多酚的食物都会增加蚯蚓防御素的浓度。这表明蚯蚓防御素可保护蚯蚓免受摄入的多酚的有害影响。我们已经确定了一个在全球土壤有机物循环中起重要作用的动物群体适应食物挑战的关键机制。
人们对食碎屑无脊椎动物如何应对高含量的植物防御性多酚知之甚少。在此，利贝克等人在接触富含多酚食物的蚯蚓中发现了一类新的表面活性代谢物，并表明它们对蛋白质沉淀起到保护作用。
All higher plants produce polyphenols, for defence against above-ground herbivory. These polyphenols also influence the soil micro- and macro-fauna that break down plant leaf litter. Polyphenols therefore indirectly affect the fluxes of soil nutrients and, ultimately, carbon turnover and ecosystem functioning in soils. It is unknown how earthworms, the major component of animal biomass in many soils, cope with high-polyphenol diets. Here, we show that earthworms possess a class of unique surface-active metabolites in their gut, which we term ‘drilodefensins'. These compounds counteract the inhibitory effects of polyphenols on earthworm gut enzymes, and high-polyphenol diets increase drilodefensin concentrations in both laboratory and field populations. This shows that drilodefensins protect earthworms from the harmful effects of ingested polyphenols. We have identified the key mechanism for adaptation to a dietary challenge in an animal group that has a major role in organic matter recycling in soils worldwide. Little is known about how detritivorous invertebrates cope with high levels of defensive plant polyphenols. Here, Liebeke et al. identify a new class of surface-active metabolites in earthworms exposed to high-polyphenol diets, and show that they play a protective role against precipitation of proteins.