红树植物根际土壤细菌分离鉴定及抑菌活性的研究

Study on isolation and identification of rhizosphere soil bacteria from mangrove plants and their antibacterial activity

为了从红树林植物根际土壤中分离出具有广谱抑菌作用的海洋细菌,试验以大肠杆菌、金黄色葡萄球菌、沙门氏菌、链球菌4种常见致病菌为指示菌,采用M10和P3培养基从红树植物根际土壤中分离细菌,以固体琼脂打孔法对分离的细菌进行抑菌活性筛选,并提取分离菌株的基因组DNA,PCR扩增16S rDNA基因并测序,同时采用邻接法构建系统发育树。结果表明:从红树植物土壤中分离得到654株细菌,其中107株细菌具有抑菌活性,占分离菌株的16.4%。菌株M36对大肠杆菌和链球菌抑菌活性最强,抑菌圈直径分别为13 mm、16 mm;菌株P19和P25对金黄色葡萄球的抑菌活性最强,抑菌圈直径均为16 mm;菌株P83对沙门氏菌抑菌活性最强,抑菌圈直径为13 mm;菌株M36和P31的抑菌谱最广。综合两种培养基的培养结果有抑菌活性的菌株被分成4个属,分别是肠杆菌属、芽孢杆菌属、葡萄球菌属、伯克霍尔德氏菌属,其中肠杆菌属为优势菌属,其次为芽孢杆菌属,占比分别为69.2%和15.9%。说明红树植物根际土壤中存在具有广谱抑菌活性的细菌。

In order to isolate marine bacteria with broad-spectrum bacterial inhibition from the rhizosphere soil of mangrove plants,the experiment was conducted with four common pathogenic bacteria as indicator bacteria,E.coli,Staphylococcus aureus,Salmonella and Streptococcus.Bacteria were isolated from the rhizosphere soil of mangrove plants using M10 and P3 media,and the isolates were screened for antibacterial activity by solid agar punching method;genomic DNA of the isolates was extracted;16S rDNA gene was amplified by PCR and sequenced,while a phylogenetic tree was constructed by using the neighbor-joining method.The results showed that 654 strains of bacteria were isolated from the soil of mangrove plants,among which 107 strains had antibacterial activity,accounting for 16.4%of the isolated strains.Strain M36 had the strongest antibacterial activity against E.coli and Streptococcus,with a circle diameter of 13 mm and 16 mm,respectively;strains P19 and P25 had the strongest antibacterial activity against S.aureus,with a circle diameter of 16 mm;strain P83 had the strongest antibacterial activity against Salmonella,with a circle diameter of 13 mm;strains M36 and P31 had the broadest antibacterial spectrum.The strains with antibacterial activity were classified into four genera,namely Enterobacter,Bacillus,Staphylococcus,and Burkholderia,based on the results of the two media,among which Enterobacter was the dominant genus,followed by Bacillus,accounting for 69.2%and 15.9%,respectively.The results suggested that there were bacteria with broad-spectrum antibacterial activity in the rhizosphere soil of mangrove plants.