目的 研究健康西洋参和患根腐病西洋参的根际土壤细菌群落结构变化，为查明西洋参根腐病发生机制提供线索。方法 以未种过西洋参的土壤（C组）、4年生健康参根际土壤（N组）和4年生根腐病参根际土壤（R组）为研究对象，采用Illumina Miseq高通量测序技术分析了土壤细菌群落结构的变化。结果 9个土壤样品基因组经16 S测序共获得有效序列636 654条，用于物种分类的OTUs 8 422个，涵盖了42门、106纲、180目、158科、246属。在门的水平上，3组细菌主要类群基本一致，主要有变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、酸杆菌门（Acidobacteria）和绿弯菌门（Chloroflexi）等，但不同组中各类群相对丰度存在明显差异；在属的水平上，3组细菌群落组成及相对丰度差别很大，其中红游动菌属Rhodoplanes、Kaistobacter属、鞘脂菌属Sphingobium等可能是引起西洋参根腐病发生的关键菌群，后续研究应重点关注。结论 西洋参根腐病株和健株根际土壤微生物组成具有显著性差异，对于探究西洋参根腐病发生的微生态机制和改良种植西洋参土壤微生物具有理论指导作用。

Objective In this paper, the changes of bacterial community structure in the rhizosphere soil of healthy and root-rot Panax quinquefolius were investigated to explore the occurrence mechanism of root-rot in P. quinquefolius. Methods The changes of bacterial communities structure in uncultivated soil (group C), rhizosphere soil of 4-year-old healthy ginseng (group N), and 4-year-old root-rot ginseng (group R) were analyzed by using the Illumina MiSeq high-throughput sequencing technology. Results A total of 636 654 effective sequences and 8 422 OTUs were obtained from nine samples based on high-throughput sequencing of the 16S gene. Bacterial species detected in these samples covered 42 phyla, 106 classes, 180 orders, 158 families, and 246 genera. The main phylums were the same in the three groups, including Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi with significantly different relative abundance. At the genera level, the composition and relative abundance of the bacterial communities in the three groups are very different. Among them, Rhodoplanes, kaistobacter, and Sphingobium may be the key bacteria causing root rot of P. quinquefolius and should be focused in the further research. Conclusion There are significant differences in the bacterial community composition from the rhizosphere soil of healthy and root-rot P. quinquefolius. This finding plays a theoretical guiding role in exploring the micro-ecological mechanism of root-rot of P. quinquefolius and improving the soil microbial community during the cultivation of P. quinquefolius.

国家自然科学基金项目（31660153）；陕西理工大学科研基金项目（SLGKY16-23）；陕西省科技统筹项目（2015KTTSSF01-02）