Abstract:

Objective To investigate the bacterial community composition and diversity in Haemaphysalis longicornis. Methods The metagenomic 16S rDNA V3-V4 profiling of bacteria were sequenced by Illumina Miseq PE300 sequencing platform to describe the bacterial community in H. longicornis ticks, to evaluate bacterial population diversity and to identify the predominant microorganisms and distribution of pathogens. Results A total of 1 070 624 Tags and 145 479 OTUs were obtained for the study. Rarefaction analysis showed a rare factional Shannon-Wiener index reaching a plateau, which indicated that sufficient numbers of sequences had been sequenced for diversity analyses and the richness of bacteria of H. longicornis. The predominated phyla in the H. longicornis were Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes sequentially. Gammaproteobacteria class showed the highest relative abundance. Also we identified a core bacterial community and divided the ticks into two groups. The 21 and 11 unique bacterial communities were detected in individual group, GⅠ and GⅡ respectively. A large number of pathogenic bacteria and opportunistic pathogens were found, there were no Spirochaeta and Mycoplasma present in the tick samples. Conclusion The bacterial community structure and distribution of pathogens obtained from H. longicornis ticks showed a high diversity.

Key words: Haemaphysalis longicornis, Bacterial community structure, Diversity, Next-generation sequencing

摘要：

目的 了解长角血蜱细菌的群落结构及种群多样性。方法 应用Illumina Miseq PE300二代测序技术测定长角血蜱细菌16S rDNA基因的V3～V4高变异区段序列，分析其细菌的群落结构、种群多样性、优势菌群以及常见病原菌的分布。结果 获得用于分析的序列和OTU数目分别为1 070 624条和145 479个；香农多样性指数的稀疏曲线接近平台期，说明此次测序的深度合适，可充分代表长角血蜱细菌的实际种群结构。长角血蜱微生物优势菌群依次为变形菌门、厚壁菌门、放线菌门和拟杆菌门，其中以γ-变形菌纲相对丰度最高。长角血蜱的“核心微生物群”，聚集成2个“蜱簇”，GⅠ和GⅡ簇分别有21和11个特有微生物群。发现菌群中存在大量致病菌和条件致病菌，但未检测到螺旋体和支原体。结论 野外长角血蜱携带的微生物物种组成和丰度均表现了较大差异性。

关键词: 长角血蜱, 细菌群落结构, 多样性, 二代测序