不同栽培方式的铁皮石斛根、茎中内生细菌多样性及其抑菌活性研究

Diversity and antibacterial activity of endophytic bacteria in roots and stems of Dendrobium officinale with different cultivation patterns

摘要:

[目的] 分析树干仿生栽培和大棚种植的铁皮石斛根、茎中内生细菌的组成与分布，并挖掘潜在的微生物资源及功能。[方法] 利用Illumina MiSeq高通量测序技术，对不同栽培方式铁皮石斛根、茎中免培养内生细菌丰富度及多样性进行比较分析；通过传统的内生菌分离法以及16S rRNA基因测序技术对可培养内生细菌进行分离鉴定；采用滤纸片法筛选拮抗石斛病原菌的内生菌株。[结果] 高通量测序分析中内生细菌以Pseudomonas （30.52%）为主，其次是Mycobacterium （10.22%）以及Brachybacterium （8.32%），树干仿生栽培石斛内生细菌组成丰富度及多样性高于大棚种植，石斛根中内生细菌组成丰富度及多样性高于石斛茎。可培养内生细菌中Bacillus （18.37%）所占比例最高，其次是Curtobacterium （8.16%），同时筛选得到8株具有抑制石斛病原菌活性的菌株。[结论] 铁皮石斛中蕴含着丰富的内生细菌资源，菌群组成和分布受其不同栽培方式和组织部位的影响。此外，筛选得到8株具有抑制病原菌活性的菌株，表明铁皮石斛内生细菌代谢产物具有抗菌活性。本试验对铁皮石斛内生细菌多样性及其抑菌活性的分析研究，为石斛内生微生物资源的后续深度挖掘以及利用提供了内生细菌资源。

Abstract:

[Objective] To explore the potential microbial resources and functions, this study analyzed the diversity of endophytic bacteria in the roots and stems of Dendrobium officinale cultivated on trunks and in greenhouses. [Methods] The composition and distribution of the endophytic bacterial community were analyzed by Illumina MiSeq High-throughput sequencing. Meanwhile, the endophytic bacteria were isolated using the traditional culture method and identified by 16S rRNA gene sequence analysis. The Kirby-Bauer test was used for detecting antimicrobial activity. [Results] The results showed that the culture-independent bacteria mainly belonged to Pseudomonas (30.52%), followed by Mycobacterium (10.22%) and Brachybacterium (8.32%). The abundance and diversity of endophytic bacteria of Dendrobium officinale cultivated on trunks were higher than that cultivated in greenhouse. The endophytic bacteria of Dendrobium officinale in root showed more abundance and diversity than in the stems. Bacillus (18.37%) accounted for the highest proportion of the culturable endophytic bacteria, followed by Curtobacterium (8.16%). Meanwhile, 8 strains showed antimicrobial activity against at least one pathogen in this study. [Conclusion] The result demonstrated that there was a huge resource of endophytic bacteria in the Dendrobium officinale. The distribution of the endophytic bacterial community was influenced by the difference of cultivation patterns and tissues. In addition, the strains with antimicrobial activity could be used as biological control of pathogenic bacteria. This study provides a diverse endophytic microbial resource of Dendrobium for further exploring and utilizing.