Bacterial microbiota composition of Ixodes ricinus ticks: the role of environmental variation, tick characteristics and microbial interactions
Bacterial microbiota composition of Ixodes ricinus ticks: the role of environmental variation, tick characteristics and microbial interactions
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DOI：
10.7717/peerj.8217
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发表时间：
2019-12-19
期刊：
影响因子：
2.7
通讯作者：
Tschirren, Barbara
中科院分区：
文献类型：
--
作者：
Aivelo, Tuomas;Norberg, Anna;Tschirren, Barbara
生态因素、宿主特征和/或微生物之间的相互作用都可能塑造微生物的出现和生物体内微生物群落的结构。在过去，将这些因素分开并确定它们在形成宿主内微生物群落方面的相对重要性一直受到分析限制的阻碍，无法解释(不)相似的环境偏好(“环境过滤”)。在这里，我们使用联合物种分布模型(JSDM)方法来表征欧洲最重要的疾病媒介之一--绵羊硬蜱的细菌微生物区系，沿着瑞士阿尔卑斯山的生态梯度。尽管我们的研究捕捉到了沿海拔倾斜的广泛的环境变化，但这种大规模生态因素的解释能力相对较弱，这表明扁虱特有的特征和行为、扁虱所经历的微生境和气候以及微生物之间的相互作用在形成扁虱微生物群落方面发挥了重要作用。事实上，当考虑到共同的环境偏好时，发现了微生物之间积极或消极共生的显著模式的证据，这表明竞争或促进过程。易化信号主要是在人类病原体之间观察到的，导致在硬蜱体内的共同感染，而硬蜱内共生体螺旋体和人类病原体之间则观察到竞争信号。这些发现突显了小规模生态变化和微生物-微生物相互作用在塑造壁虱微生物群落和壁虱传播疾病动态方面的重要作用。
Ecological factors, host characteristics and/or interactions among microbes may all shape the occurrence of microbes and the structure of microbial communities within organisms. In the past, disentangling these factors and determining their relative importance in shaping within-host microbiota communities has been hampered by analytical limitations to account for (dis)similar environmental preferences ('environmental filtering'). Here we used a joint species distribution modelling (JSDM) approach to characterize the bacterial microbiota of one of the most important disease vectors in Europe, the sheep tick Ixodes ricinus, along ecological gradients in the Swiss Alps. Although our study captured extensive environmental variation along elevational clines, the explanatory power of such large-scale ecological factors was comparably weak, suggesting that tick-specific traits and behaviours, microhabitat and -climate experienced by ticks, and interactions among microbes play an important role in shaping tick microbial communities. Indeed, when accounting for shared environmental preferences, evidence for significant patterns of positive or negative co-occurrence among microbes was found, which is indicative of competition or facilitation processes. Signals of facilitation were observed primarily among human pathogens, leading to co-infection within ticks, whereas signals of competition were observed between the tick endosymbiont Spiroplasma and human pathogens. These findings highlight the important role of small-scale ecological variation and microbe-microbe interactions in shaping tick microbial communities and the dynamics of tickborne disease.