Department for Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 13, 55128, Mainz, Germany.
Department of Biomolecular Chemistry, Leibniz Institute for Natural Products Research and Infection Biology, HKI, Beutenbergstr. 11a, 07745, Jena, Germany.
Nat Commun. 2018 Jun 26;9(1):2478. doi: 10.1038/s41467-018-04955-6.
Microbial symbionts are often a source of chemical novelty and can contribute to host defense against antagonists. However, the ecological relevance of chemical mediators remains unclear for most systems. Lagria beetles live in symbiosis with multiple strains of Burkholderia bacteria that protect their offspring against pathogens. Here, we describe the antifungal polyketide lagriamide, and provide evidence supporting that it is produced by an uncultured symbiont, Burkholderia gladioli Lv-StB, which is dominant in field-collected Lagria villosa. Interestingly, lagriamide is structurally similar to bistramides, defensive compounds found in marine tunicates. We identify a gene cluster that is probably involved in lagriamide biosynthesis, provide evidence for horizontal acquisition of these genes, and show that the naturally occurring symbiont strains on the egg are protective in the soil environment. Our findings highlight the potential of microbial symbionts and horizontal gene transfer as influential sources of ecological innovation.
微生物共生体通常是化学新颖性的来源，并能有助于宿主抵御拮抗剂。然而，对于大多数系统来说，化学介质的生态相关性仍不清楚。Lagria 甲虫与多种 Burkholderia 细菌共生，这些细菌保护它们的后代免受病原体的侵害。在这里，我们描述了抗真菌聚酮 lagriamide，并提供了证据支持它是由未培养的共生体 Burkholderia gladioli Lv-StB 产生的，该共生体在野外采集的 Lagria villosa 中占优势。有趣的是，lagriamide 在结构上与海洋被囊动物中的防御化合物 bistramides 相似。我们确定了一个可能参与 lagriamide 生物合成的基因簇，提供了这些基因水平获得的证据，并表明在土壤环境中，自然存在于卵上的共生菌株具有保护作用。我们的发现强调了微生物共生体和水平基因转移作为生态创新的有影响力的来源的潜力。
