Bacterial endosymbionts protect beneficial soil fungus from nematode attack.
Bacterial endosymbionts protect beneficial soil fungus from nematode attack.
复制标题
DOI：
10.1073/pnas.2110669118
复制
发表时间：
2021-09-14
影响因子：
11.1
通讯作者：
Hertweck C
中科院分区：
文献类型：
--
作者：
Büttner H;Niehs SP;Vandelannoote K;Cseresnyés Z;Dose B;Richter I;Gerst R;Figge MT;Stinear TP;Pidot SJ;Hertweck C
土壤是一个复杂而竞争激烈的环境，迫使其居民制定策略来对抗竞争对手，捕食者和病原体。识别和理解分子机制对医学、生态学和农业具有转化价值。在这项研究中，我们表明，一个重要的土壤真菌（被孢霉属）的成员形成了紧密的联盟与产毒细菌（Mycoavidus），生活在真菌菌丝和保护他们的主机从线虫的攻击。这一发现是相关的，因为被孢霉属物种与健康的土壤相关，并在农业中用作植物生长促进真菌。揭示了真菌内共生菌在被孢霉属中的生态作用，我们的研究结果有助于了解真菌-内细菌共生的主要动力，并为开发新的生物防治剂提供了可能性。被孢霉属真菌广泛存在于土壤中，它们在碳循环、降解外来生物体和促进植物生长方面发挥着关键作用。然而，这些重要的真菌受到微捕食者如食真菌线虫的威胁，但对它们的保护策略知之甚少。我们报告说，被孢霉轮叶孢NRRL 6337窝藏细菌内共生体，有效地屏蔽其主机从线虫攻击驱虫代谢产物。显微镜观察和16 S核糖体DNA分析表明，以前被忽视的细菌共生体属于Mycoavidus居住在M。轮生菌丝野生型真菌和通过抗生素处理获得的无共生体菌株的代谢谱以及基因组分析揭示了高细胞毒性大环内酯（CJ-12，950和CJ-13，357，syn.坏死肟C和D），最初被认为是土壤真菌的代谢产物，实际上是由内共生体生物合成的。根据比较基因组学，共生体属于一个新的物种（Mycoavidus necroximicus），其2.2 Mb的基因组中有12%致力于天然产物的生物合成，包括用于necroxime组装的模块化聚酮-非核糖体肽合成酶。使用秀丽隐杆线虫和食真菌线虫燕麦线虫作为测试菌株，我们表明，necroximes发挥高度有效的驱虫活性。在线虫与共生和化学互补的非共生真菌菌株的共培养物中证明了有效的宿主保护。线虫运动的图像分析和数学定量使得能够评价效力。我们的工作描述了一个相关的作用，内生真菌细菌在保护真菌对食菌线虫。
Soil is a complex and competitive environment, forcing its inhabitants to develop strategies against competitors, predators, and pathogens. Identifying and understanding the molecular mechanisms has translational value for medicine, ecology, and agriculture. In this study, we show that a member of important soil-dwelling fungi (Mortierella) forms a tight alliance with toxin-producing bacteria (Mycoavidus) that live within the fungal hyphae and protect their host from nematode attack. This discovery is relevant since Mortierella species correlate with healthy soils and are used as plant growth–promoting fungi in agriculture. Unraveling an ecological role for fungal endosymbionts in Mortierella, our results contribute to the understanding of a mainspring in fungal–endobacterial symbioses and open the possibility for the development of new biocontrol agents. Fungi of the genus Mortierella occur ubiquitously in soils where they play pivotal roles in carbon cycling, xenobiont degradation, and promoting plant growth. These important fungi are, however, threatened by micropredators such as fungivorous nematodes, and yet little is known about their protective tactics. We report that Mortierella verticillata NRRL 6337 harbors a bacterial endosymbiont that efficiently shields its host from nematode attacks with anthelmintic metabolites. Microscopic investigation and 16S ribosomal DNA analysis revealed that a previously overlooked bacterial symbiont belonging to the genus Mycoavidus dwells in M. verticillata hyphae. Metabolic profiling of the wild-type fungus and a symbiont-free strain obtained by antibiotic treatment as well as genome analyses revealed that highly cytotoxic macrolactones (CJ-12,950 and CJ-13,357, syn. necroxime C and D), initially thought to be metabolites of the soil-inhabiting fungus, are actually biosynthesized by the endosymbiont. According to comparative genomics, the symbiont belongs to a new species (Candidatus Mycoavidus necroximicus) with 12% of its 2.2 Mb genome dedicated to natural product biosynthesis, including the modular polyketide-nonribosomal peptide synthetase for necroxime assembly. Using Caenorhabditis elegans and the fungivorous nematode Aphelenchus avenae as test strains, we show that necroximes exert highly potent anthelmintic activities. Effective host protection was demonstrated in cocultures of nematodes with symbiotic and chemically complemented aposymbiotic fungal strains. Image analysis and mathematical quantification of nematode movement enabled evaluation of the potency. Our work describes a relevant role for endofungal bacteria in protecting fungi against mycophagous nematodes.
登录
查看更多内容
影响因子：
--
作者：
Edgington, Steven;Thompson, Emma;Bridge, Paul
通讯作者：
Bridge, Paul
影响因子：
3.6
作者：
Ellegaard-Jensen, Lea;Aamand, Jens;Rosendahl, Soren
通讯作者：
Rosendahl, Soren
影响因子：
5
作者：
Degenkolb T;Vilcinskas A
通讯作者：
Vilcinskas A
影响因子：
4.7
作者：
Li, Fang;Chen, Lin;Li, Wei
通讯作者：
Li, Wei
对90K核基因组的高通量ANI分析揭示了清晰的物种边界。
影响因子：
16.6
作者：
Jain C;Rodriguez-R LM;Phillippy AM;Konstantinidis KT;Aluru S
通讯作者：
Aluru S