PDF(Pubmed)
Abstract：
Amblyomma americanum, a known vector of multiple tick-borne pathogens, has expanded its geographic distribution across the United States in the past decades. Tick microbiomes may play a role shaping their host\'s life history and vectorial capacity. Bacterial communities associated with A. americanum may reflect, or enable, geographic expansion and studying the microbiota will improve understanding of tick-borne disease ecology. We examined the microbiota structure of 189 adult ticks collected in four regions encompassing their historical and current geographic distribution. Both geographic region of origin and sex were significant predictors of alpha diversity. As in other tick models, within-sample diversity was low and uneven given the presence of dominant endosymbionts. Beta diversity analyses revealed that bacterial profiles of ticks of both sexes collected in the West were significantly different from those of the Historic range. Biomarkers were identified for all regions except the historical range. In addition, Bray-Curtis dissimilarities overall increased with distance between sites. Relative quantification of ecological processes showed that, for females and males, respectively, drift and dispersal limitation were the primary drivers of community assembly. Collectively, our findings highlight how microbiota structural variance discriminates the western-expanded populations of A. americanum ticks from the Historical range. Spatial autocorrelation, and particularly the detection of non-selective ecological processes, are indicative of geographic isolation. We also found that prevalence of Ehrlichia chaffeensis, E. ewingii, and Anaplasma phagocytophilum ranged from 3.40-5.11% and did not significantly differ by region. Rickettsia rickettsii was absent from our samples. Our conclusions demonstrate the value of synergistic analysis of biogeographic and microbial ecology data in investigating range expansion in A. americanum and potentially other tick vectors as well.
摘要：
美洲弱视，一种已知的多种蜱传病原体的媒介，在过去的几十年里，扩大了它在美国各地的地理分布。滴答微生物组可能在塑造其宿主的生活史和矢量能力方面发挥作用。与美洲曲霉相关的细菌群落可能反映，或启用，地理扩展和研究微生物群将提高对蜱传疾病生态学的理解。我们检查了在四个地区收集的189个成年蜱的微生物群结构，包括它们的历史和当前地理分布。地理区域和性别都是α多样性的重要预测因子。与其他滴答模型一样，鉴于存在优势的内共生体，样本内多样性低且不均匀。Beta多样性分析显示，在西部收集的两种性别的蜱的细菌谱与历史范围的细菌谱明显不同。除历史范围外，所有地区都确定了生物标志物。此外,Bray-Curtis的差异总体上随着站点之间的距离而增加。生态过程的相对量化表明，对于女性和男性，分别,漂移和分散限制是社区集会的主要驱动因素。总的来说，我们的研究结果强调了微生物群结构差异如何区分历史范围内的美洲A.空间自相关，特别是检测非选择性生态过程，表示地理隔离。我们还发现恰菲埃里希菌的患病率，E.艾文吉,和吞噬细胞无性体的范围为3.40-5.11％，各地区没有显着差异。我们的样品中没有立克次体立克次体。我们的结论证明了生物地理和微生物生态学数据的协同分析在调查美洲A.americanum和潜在的其他tick矢量的范围扩展中的价值。
