Data from: Microbiome changes through ontogeny of a tick pathogen vector

Blacklegged ticks (Ixodes scapularis) are one of the most important pathogen vectors in the United States, responsible for transmitting Lyme disease and other tick-borne diseases. The structure of a host's microbial community has the potential to affect the ecology and evolution of the host. We employed high-throughput sequencing of the 16S rRNA gene V3-V4 hypervariable regions in the first study to investigate the tick microbiome across all developmental stages (larvae, nymphs, adults). In addition to field-collected life stages, newly hatched lab-reared larvae were studied to determine the baseline microbial community structure and to assess transovarial transmission. We also targeted midguts and salivary glands due to their importance in pathogen maintenance and transmission. Over 100,000 sequences were produced per life stage replicate. Rickettsia was the most abundant bacterial genus across all sample types matching mostly the Ixodes rickettsial endosymbionts, and its proportion decreased as developmental stage progressed, with the exception of adult females that harbored a mean relative abundance of 97.9%. Lab-reared larvae displayed the lowest bacterial diversity, containing almost exclusively Rickettsia. Many of the remaining bacteria included genera associated with soil, water, and plants, suggesting environmental acquisition while off-host. Female organs exhibited significantly different β-diversity than the whole tick from which they were derived. Our results demonstrate clear differences in both α and β diversity among tick developmental stages and between tick organs and the tick as a whole. Furthermore, field-acquired bacteria appear to be very important to the overall internal bacterial community of this tick species, with influence from the host blood meal appearing limited.黑腿蜱（Ixodes scapularis）是美国境内最重要的病原媒介生物之一，可传播莱姆病及其他蜱传疾病。蜱虫宿主的微生物群落结构可对其自身的生态与演化产生潜在影响。本研究首次运用16S rRNA基因V3-V4高变区高通量测序技术，对该蜱虫各发育阶段（幼虫、若虫、成虫）的微生物组展开分析。除野外采集的各发育阶段样本外，本研究还针对实验室饲养的刚孵化幼虫进行研究，以明确其微生物群落结构的基线水平，并评估经卵传播现象。鉴于中肠与唾液腺在病原维持及传播过程中的关键作用，本研究同时对这两类器官进行了靶向分析。每个发育阶段的重复样本均获得了超过10万条有效测序序列。立克次体属（Rickettsia）是所有样本类型中丰度最高的细菌类群，其序列主要与肩突硬蜱立克次体内共生菌匹配；随着发育阶段推进，该类群的相对占比逐渐下降，但成年雌蜱例外，其体内立克次体的平均相对丰度达97.9%。实验室饲养的幼虫细菌多样性最低，其菌群几乎完全由立克次体属构成。其余多数细菌类群均隶属于与土壤、水体及植物相关的菌属，提示该蜱虫在非寄生阶段可通过环境途径获得这些微生物。雌性蜱虫的器官微生物群落β多样性与其来源的整蜱存在显著差异。本研究结果表明，蜱虫各发育阶段之间，以及蜱虫器官与整蜱整体之间的α多样性与β多样性均存在显著差异。此外，野外环境中获得的细菌对该蜱虫的体内整体菌群结构至关重要，而宿主血液餐对菌群的影响则相对有限。