Zoological Institute, Christian-Albrechts University of Kiel, 24098 Kiel, Germany.
Proc Natl Acad Sci U S A. 2013 Sep 24;110(39):E3730-8. doi: 10.1073/pnas.1304960110. Epub 2013 Sep 3.
Animals are colonized by coevolved bacterial communities, which contribute to the host's health. This commensal microbiota is often highly specific to its host-species, inferring strong selective pressures on the associated microbes. Several factors, including diet, mucus composition, and the immune system have been proposed as putative determinants of host-associated bacterial communities. Here we report that species-specific antimicrobial peptides account for different bacterial communities associated with closely related species of the cnidarian Hydra. Gene family extensions for potent antimicrobial peptides, the arminins, were detected in four Hydra species, with each species possessing a unique composition and expression profile of arminins. For functional analysis, we inoculated arminin-deficient and control polyps with bacterial consortia characteristic for different Hydra species and compared their selective preferences by 454 pyrosequencing of the bacterial microbiota. In contrast to control polyps, arminin-deficient polyps displayed decreased potential to select for bacterial communities resembling their native microbiota. This finding indicates that species-specific antimicrobial peptides shape species-specific bacterial associations.
动物被共同进化的细菌群落定植，这些细菌群落有助于宿主的健康。这种共生微生物群落通常对其宿主物种高度特异，这表明相关微生物受到强烈的选择性压力。包括饮食、粘液组成和免疫系统在内的几个因素被认为是宿主相关细菌群落的潜在决定因素。在这里，我们报告称，物种特异性的抗菌肽解释了与刺胞动物门水螅属的密切相关物种相关的不同细菌群落。在四种水螅物种中检测到了强效抗菌肽阿米宁的基因家族扩展，每种物种都具有独特的阿米宁组成和表达谱。为了进行功能分析，我们用不同水螅物种特有的细菌共生体接种阿米宁缺陷和对照水螅息肉，并通过 454 焦磷酸测序比较它们对细菌微生物组的选择性偏好。与对照息肉相比，阿米宁缺陷息肉对类似于其天然微生物组的细菌群落的选择潜力降低。这一发现表明，物种特异性的抗菌肽塑造了物种特异性的细菌关联。
