药用植物刺山柑不同部位细菌群落结构及其多样性

【目的】研究传统药用植物刺山柑（Capparis spinosa L.）不同部位细菌群落结构、物种组成和多样性特征，为药用植物微生物资源的开发及微生物与宿主互作提供理论依据。【方法】本研究以刺山柑地上部植物组织（果实、茎）和地下部土壤（根际土壤、非根际土壤）为研究材料，采用高通量测序技术分析刺山柑不同部位细菌的16S rRNA基因多样性，比较其细菌群落结构和物种组成特征。【结果】刺山柑4种样本共获得的3 649个操作分类单元（operational taxonomic unit，OTU），属于34门、88纲、248目、464科和1 051属。土壤样本的细菌多样性大于植物组织，细菌群落多样性以根际土壤、非根际土壤、茎和果实的顺序逐渐降低，果实内生细菌群落多样性始终最低，显著低于根际土壤。不同部位相对丰度较高的细菌门如下：植物组织中以变形菌门为主，根际土壤中为变形菌门和放线菌门，非根际土中为厚壁菌门和放线菌门。无色杆菌属（Achromobacter）、欧文氏菌属（Erwinia）、肠球菌属（Enterococcus）、微小杆菌属（Exiguobacterium）、乳杆菌属（Lactobacillus）和克雷伯氏菌属（Klebsiella）主要存在于刺山柑植物组织中。游动球菌属（Planomicrobium）、库克菌属（Kocuria）、类芽孢杆菌属（Paenibacillus）、链霉菌属（Streptomyces）、微枝形杆菌属（Microvirga）和节杆菌属（Arthrobacter）主要分布于土壤中。β多样性分析结果表明，刺山柑植物组织和土壤的细菌群落结构具有显著差异，同类型样本的细菌群落结构相似。【结论】刺山柑土壤样本中细菌群落的多样性和丰富度均高于植物组织，刺山柑不同部位的细菌群落组成不同。本研究对刺山柑不同部位细菌群落结构进行了初步分析，鉴定了各部位细菌群落中的核心菌群，为以后挖掘刺山柑的功能研究和利用提供了准确的微生物信息。

Bacterial diversity and communities in different parts of the medicinal plant Capparis spinosa L.

[Objective] To understand the bacterial community structures, species composition, and diversity in different parts of the medicinal plant Capparis spinosa L., so as to provide a theoretical basis for developing the microbial resources in medicinal plants and revealing the interactions between microorganisms and hosts. [Methods] The aboveground tissue (fruit and stem) samples of plants and soil (rhizosphere soil and bulk soil) samples were collected. High-throughput sequencing of bacterial 16S rRNA gene hypervariable regions V5-V7 and V3-V4 was employed to compare the bacterial community structure, species composition, and function in different samples. [Results] A total of 3 649 (operational taxonomic unit, OTUs) were annotated for the sequencing results of the four samples, belonging to 1 051 genera, 464 families, 248 orders, 88 classes of 34 phyla. The bacterial diversity in soil samples was higher than that in plant samples, following the trend of rhizosphere soil>bulk soil>stems>fruits. The bacterial diversity in fruits was always the lowest and significantly lower than that in rhizosphere soil. At the phylum level, Proteobacteria was dominant in plant samples, Proteobacteria and Actinobacteriota in rhizosphere soil, and Firmicutes and Actinobacteriota in bulk soil. At the genus level, Achromobacter, Erwinia, Enterococcus, Exiguobacterium, Lactobacillus, and Klebsiella were dominant in the plant samples, and Planomicrobium,Kocuria, Paenibacillus, Streptomyces, Microvirga, and Arthrobacter in the soil samples. The beta diversity analysis indicated that the bacterial community structure had significant differences between plant samples and soil samples and was similar in the same type of samples. [Conclusion] The bacterial diversity and abundance in soil samples were higher than those in plant samples, and the bacterial community structure varied between different parts of Capparis spinosa L. The findings provide accurate microbial information for exploring the function of and utilizing the bacteria in this medicinal plant.