Despite the deep knowledge of the honey bee (Apis mellifera) gut microbiome, information on the microbial communities of other hive components is still scarce. Propolis originates from a natural resinous mixture that honeybees collect from different plants sources and modify; it is used mainly to ensure the hygiene of the hive. By virtue of its antimicrobial properties, propolis has been considered relatively aseptic, yet its ability to harbor microorganisms has not been previously investigated. In this study we report the first description of the diversity of the microbial community of propolis by both targeted-metagenomics analysis and cultivation. We demonstrated that propolis hosts a variety of microbial strains belonging to taxa already described in other hive components. Some of them are cultivable in standard laboratory conditions, and show metabolic characteristics compatible with their persistence in different physiological states inside propolis. Isolated bacteria produce antimicrobials against Gram-negative and Gram-positive bacteria, and entomopathogenic fungi, with different spectra of inhibition. Metagenomics analysis shows the presence of bacteria and fungi with great potential to outcompete potentially harmful microorganisms. These findings suggest that the characterized microbiota could contribute to the overall antimicrobial properties of propolis and to its ecological role as "disinfectant" within the hive.

中文翻译：

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蜂胶拥有多样化的微生物群落

尽管对蜜蜂（Apis mellifera）肠道微生物组有深入了解，但关于其他蜂巢成分的微生物群落的信息仍然很少。蜂胶源自蜜蜂从不同植物来源收集并改性的天然树脂混合物；它主要用于确保蜂巢的卫生。凭借其抗菌特性，蜂胶被认为是相对无菌的，但之前尚未研究过它携带微生物的能力。在这项研究中，我们报告了通过靶向宏基因组学分析和培养对蜂胶微生物群落多样性的首次描述。我们证明蜂胶承载着属于已经在其他蜂巢组件中描述的分类群的各种微生物菌株。其中一些可以在标准实验室条件下培养，并显示出与它们在蜂胶内不同生理状态下的持久性相适应的代谢特征。分离的细菌对革兰氏阴性菌和革兰氏阳性菌以及昆虫病原真菌产生抗菌剂，具有不同的抑制谱。宏基因组学分析表明，细菌和真菌的存在具有战胜潜在有害微生物的巨大潜力。这些发现表明，所表征的微生物群可能有助于蜂胶的整体抗菌特性及其作为蜂巢内“消毒剂”的生态作用。具有不同的抑制谱。宏基因组学分析表明，细菌和真菌的存在具有战胜潜在有害微生物的巨大潜力。这些发现表明，所表征的微生物群可能有助于蜂胶的整体抗菌特性及其作为蜂巢内“消毒剂”的生态作用。具有不同的抑制谱。宏基因组学分析表明，细菌和真菌的存在具有战胜潜在有害微生物的巨大潜力。这些发现表明，所表征的微生物群可能有助于蜂胶的整体抗菌特性及其作为蜂巢内“消毒剂”的生态作用。