Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel.
NPJ Biofilms Microbiomes. 2021 Jan 5;7(1):2. doi: 10.1038/s41522-020-00174-4.
The soil bacterium Bacillus subtilis forms beneficial biofilms that induce plant defences and prevent the growth of pathogens. It is naturally found in the rhizosphere, where microorganisms coexist in an extremely competitive environment, and thus have evolved a diverse arsenal of defence mechanisms. In this work, we found that volatile compounds produced by B. subtilis biofilms inhibited the development of competing biofilm colonies, by reducing extracellular matrix gene expression, both within and across species. This effect was dose-dependent, with the structural defects becoming more pronounced as the number of volatile-producing colonies increased. This inhibition was mostly mediated by organic volatiles, and we identified the active molecules as 3-methyl-1-butanol and 1-butanol. Similar results were obtained with biofilms formed by phylogenetically distinct bacterium sharing the same niche, Escherichia coli, which produced the biofilm-inhibiting 3-methyl-1-butanol and 2-nonanon. The ability of established biofilms to inhibit the development and spreading of new biofilms from afar might be a general mechanism utilized by bacterial biofilms to protect an occupied niche from the invasion of competing bacteria.
土壤细菌枯草芽孢杆菌形成有益的生物膜，诱导植物防御并阻止病原体的生长。它自然存在于根际，在那里微生物在极其竞争的环境中共存，因此进化出了多样化的防御机制。在这项工作中，我们发现枯草芽孢杆菌生物膜产生的挥发性化合物通过降低细胞外基质基因的表达，抑制了竞争生物膜菌落的发育，无论是在同种内还是跨物种。这种效应是剂量依赖性的，随着产生挥发性化合物的菌落数量的增加，结构缺陷变得更加明显。这种抑制主要是由有机挥发物介导的，我们确定了活性分子是 3-甲基-1-丁醇和 1-丁醇。具有相同生态位的系统发育上不同的细菌（大肠杆菌）形成的生物膜也得到了类似的结果，大肠杆菌产生了抑制生物膜形成的 3-甲基-1-丁醇和 2-壬酮。已建立的生物膜从远处抑制新生物膜的发育和扩散的能力可能是细菌生物膜用来保护占据的生态位免受竞争细菌入侵的一般机制。
