小花老鼠簕可培养细菌多样性及其生物学活性研究

Diversity and bioactivity of culturable bacteria from Acanthus ebracteatus

关键词:  小花老鼠簕, 可培养细菌, 植物病原菌, 捕食活性

Key words:  Acanthus ebracteatus, culturable bacteria, plant pathogens, predation activity

摘要:

小花老鼠簕(Acanthus ebracteatus)是一种生长在红树生态系统的珍稀真红树植物,具有较高的药用价值。为研究小花老鼠簕内生及根际可培养细菌多样性,挖掘其潜在新物种及具有特殊生物学活性的菌株,该文利用7种不同培养基,通过传统稀释涂布法对小花老鼠簕各植物组织及根际土壤可培养细菌进行分离,基于16S rRNA基因序列解析其内生及根际细菌群落结构和多样性特征,应用植物病原菌平板对峙实验和平铺捕食活性测试分析其可培养细菌的抗菌活性。结果表明:(1)基于16S rRNA基因序列分析,发现从小花老鼠簕的根、茎、叶、花及根际土壤中分离得到144株可培养细菌,这些细菌隶属于18目26科37属66种,芽孢杆菌属(Bacillus)和链霉菌属(Streptomyces)为优势菌属,分别占细菌种数的15.1%和13.6%;(2)拮抗多种植物病原菌试验结果显示,获得29株具有拮抗植物病原菌活性的细菌,10株具有广谱抑菌活性,其中链霉菌属菌株拮抗作用最强且菌株Y129为潜在新物种。(3)捕食活性测试结果显示,有5株细菌对金黄色葡萄球菌(Staphylococcus aureus)、耐甲氧西林金黄色葡萄球菌(multi-drug resistance Staphylococcus aureus)及大肠埃希氏菌(Escherichia coli)具有捕食活性,假单胞菌属菌株捕食活性最强,其中菌株Y90为潜在新物种。综上表明,红树植物小花老鼠簕及其根际土壤中蕴含着丰富的细菌种质资源且具有多种生物活性,可作为生防菌和药源菌的来源之一,该研究结果为提高红树植物小花老鼠簕的药效和栽培提供了理论参考。

Abstract:

Acanthus ebracteatus is a special kind of rare mangrove plant, possessing great medicinal value. In this paper, in order to study the diversity of endophytic and rhizosphere culturable bacteria in the A. ebracteatus, we explored new potential bacterial species and strains with special biological activities. The culturable bacteria were isolated from A. ebracteatus by dilution separation method. The bacterial diversity was investigated based on the 16S rRNA gene sequence analysis. In addition, the confrontation experiment and lawn predation assay were utilized to screen bacteria with anti-microorganism activities. The results were as follows:(1)A total of 144 culturable bacteria were isolated from A. ebracteatus root, stems, leaves, flowers and rhizosphere soil. These bacteria were affiliated into 66 species based on the analysis of the 16S rRNA gene sequence. The bacterial genera Bacillus and Streptomyces were dominant in plant tissue and rhizosphere soil with that of the value 15.1% and 13.6%, respectively.(2)The bioactivity assays revealed that there were 29 strains with anti-fungal activity and 10 strain possessing a broad spectrum of anti-fungal activity. Among them, the Streptomyces strains had the strongest antagonistic effect, and the active strain Y129 was a potential new species.(3)A total of five strains showed predation activity on Staphylococcus aureus, multi-drug resistance Staphylococcus aureus and Escherichia coli. Pseudomonas had the strongest predatory activity, and the active strain Y90 was a potential new species. In conclusion, A. ebracteatus and their rhizosphere soil contain rich bacterial germplasm resources and have a variety of functional strains, which can be used as one of the sources of biocontrol bacteria and medicinal bacteria. This study provides the theoretical reference for improving the efficacy and cultivation of A. ebracteatus.