双孢线虫草内生和生境土壤细菌的分离鉴定及其抑菌活性

Isolation,Identification,and Antimicrobial Activity of Endophytic and Habitat Soil Bacteria of Ophiocordyceps bispora

采用8种培养基从来自云南哀牢山的12份双孢线虫草(Ophiocordyceps bispora)的子座、菌核及其生境土壤样品中分离细菌,并对细菌进行形态学分类,进行16 S rRNA测序鉴定,同时按所获菌株来源及种类随机挑取供试菌株采用琼脂块扩散法测试对25株病原菌的抑菌活性。结果表明:从双孢线虫草子座、菌核和生境土壤中分离获得302株细菌,对其中275株进行测序,它们属于4门14目18科18属65种,其中链霉菌属(Streptomyces)、芽孢杆菌属(Bacillus)、类芽孢杆菌属(Paenibacillus)、诺卡氏菌属(Nocardia)和根瘤菌属(Rhizobium)为优势属;枯草芽孢杆菌(B.subtilis)、N.nova、纳塔尔链霉菌(S.natalensis)、S.angustmyceticus、高原链霉菌(S.platensis)、杀黄孢链霉菌(S.xanthocidicus)、江西诺卡氏菌(N.jiangxiensis)、高山芽孢杆菌(B.altitudinis)为优势种。就所含细菌类群而言,双孢线虫草生境土壤(16科16属57种)明显高于子座(9科9属17种)和菌核(3科3属7种)。在199株细菌中,有99株对1个以上病原菌具有抑菌活性,初筛阳性率为49.75%;其中8个优势菌株对4个及以上病原菌具有广谱且高效的抑菌活性。

Using eight culture media,cultivable bacteria in 12 stroma,sclerotium and habitat soil samples of Ophiocordyceps bispora from Ailao Mountain of Yunnan province were isolated,classified by morphology and identified by 16 S rRNA sequencing.Based on the origin and taxonomy of the obtained strains,they were randomly selected and tested for antibacterial activity against 25 pathogenic bacteria by the agar well diffusion method.The results showed that a total of 302 strains were isolated,of which 275 strains were sequenced and classified into 65 species,18 genera,18 families,14 orders,and 4 phyla.Among them,Streptomyces,Bacillus,Paenibacillus,Nocardia,and Rhizobium were the dominant endophytic bacterial genera of O.bispora,and B.subtilis,N.nova,S.natalensis,S.angustmyceticus,S.platensis,S.xanthocidicus,N.jiangxiensis,and B.altitudinis were the dominant endophytic bacterial species of O.bispora.The bacteria isolated from habitat soil(57 species,16 genera,and 16 families)were more abundant than that of stroma(17 species,9 genera,and 9 families)and sclerotium(7 species,3 genera,and 3 families).Among 199 randomly selected strains,99 strains showed antibacterial activity against at least one of the 25 pathogenic bacteria,and the positive rate of primary screening was 49.75%.Among them,eight strains showed broad-spectrum and significant antimicrobial activity against at least four pathogenic bacteria.