Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
Appl Environ Microbiol. 2019 Jun 17;85(13). doi: 10.1128/AEM.00512-19. Print 2019 Jul 1.
Microbial ecosystems tightly associated with a eukaryotic host are widespread in nature. The genetic and metabolic networks of the eukaryotic hosts and the associated microbes have coevolved to form a symbiotic relationship. Both the Gram-positive and the Gram-negative can form biofilms on plant roots and thus can serve as a model system for the study of interspecies interactions in a host-associated ecosystem. We found that biofilms expand collectively and asymmetrically toward , while expressing a nonribosomal antibiotic bacillaene and an extracellular protease. As a result, biofilms outcompeted for successful colonization of the host. Strikingly, the plant host was able to enhance the efficiency of this killing by inducing bacillaene synthesis. In turn, biofilms increased the resistance of the plant host to pathogens. These results provide an example of how plant-bacterium symbiosis promotes the immune response of the plant host and the fitness of the associated bacteria. Our study sheds mechanistic light on how multicellular biofilm units compete to successfully colonize a eukaryote host, using microbial communities as our lens. The microbiota and its interactions with its host play various roles in the development and prevention of diseases. Using competing beneficial biofilms that are essential microbiota members on the plant host, we found that biofilms activate collective migration to capture their prey, followed by nonribosomal antibiotic synthesis. Plant hosts increase the efficiency of antibiotic production by biofilms, as they activate the synthesis of polyketides; therefore, our study provides evidence of a mechanism by which the host can indirectly select for beneficial microbiota members.
与真核宿主密切相关的微生物生态系统在自然界中广泛存在。真核宿主的遗传和代谢网络与相关微生物共同进化，形成共生关系。革兰氏阳性菌和革兰氏阴性菌都可以在植物根部形成生物膜，因此可以作为研究宿主相关生态系统中种间相互作用的模型系统。我们发现生物膜集体向扩展，表现出非核糖体抗生素杆菌肽和细胞外蛋白酶。结果，生物膜成功地与竞争，从而成功地定植宿主。引人注目的是，植物宿主能够通过诱导杆菌肽合成来提高这种杀伤的效率。反过来，生物膜增加了植物宿主对病原体的抗性。这些结果提供了一个例子，说明植物-细菌共生如何促进植物宿主的免疫反应和相关细菌的适应性。我们的研究揭示了多细胞生物膜单元如何利用微生物群落作为我们的视角来竞争成功地定植真核宿主的机制。微生物群及其与宿主的相互作用在疾病的发展和预防中发挥着各种作用。利用作为植物宿主必需微生物群落成员的竞争有益生物膜，我们发现生物膜激活集体迁移以捕获其猎物，随后合成非核糖体抗生素。植物宿主通过激活聚酮化合物的合成来提高生物膜产生抗生素的效率；因此，我们的研究提供了宿主可以间接选择有益微生物群落成员的机制的证据。
