一株白芍内生放线菌的分离、活性及系统发育分析

目的:分离白芍中拮抗农作物致病菌和人类常见病原菌的内生放线菌,并进行系统发育分析。方法:采用3种分离培养基,从白芍根部分离内生放线菌;通过滤纸片法筛选具有拮抗活性的菌株,观察菌丝形态,并进行16S rDNA序列系统发育分析。结果:从白芍中分离得到16株内生放线菌,其中从FYSCA培养基中分离到9株;16株内生放线菌中有6株具有拮抗作用,菌株S-BS033004对5种病原菌有拮抗活性,尤其是对棉花黄萎病菌和小孢拟盘多毛孢菌和耐青霉素类金黄色葡萄球菌的拮抗作用显著,抑菌圈≥20mm。经16S rDNA系统发育分析表明该菌株与Streptomyces anulatus NBRC13369T等6株链霉菌模式菌株亲缘关系较近,相似性均为99.7%。结论:白芍内生放线菌S-BS033004是一株杀菌谱较广的链霉菌,具有很好的开发潜力。

Isolation, Antagonistic Activity and Phylogenetic Analysis of an Endophytic Actinomycete from Paeonia lactiflora

Objective:To isolate the endophytic actinomycete strains of resisting pathogenic organism harmming the crops and the human and analyse phylogenetic status of activated strain.Method:Three kinds of isolating media were used to isolate endophytic actinomycetes from surface-sterilized root of Paeonia lactiflora.The method of filter paper slice was used to screen the strains which had anti-microbial activity.Mycelial morphology of activated strain was observed and phylogenetic analysis was carried out.Result:Sixteen endophytic actinomycete strains were isolated from Paeonia lactiflora and nine strains were isolated on FYSCA medium.Six of sixteen strains had anti-microbial activity and S-BS033004 was found to produce antibiotic substances which showed significant inhibitory effects on 6 pathogenic organisms such as Verticillium dahliae,Fusarium Oxysporum f.sp.Vasinfectum,Bipolaris oryzae Shoem,Pestalotiopsis microspora,Curvularia lunata(Walk) Boed and Staphyloccocus aureus,especially Verticillium dahliae,Pestalotiopsis microspora and Staphyloccocus aureus of Penicillin tolerance.And the inhibition zones were all equal or greater than 20mm.The result of 16S rDNA sequence analysis showed that the strain S-BS033004 was similar to Streptomyces anulatus NBRC13369T,Streptomyces praecox NBRC13073T,Streptomyces rubiginosohelvolus NBRC12912T,Streptomyces mediolani NBRC15427T,Streptomyces griseinus NBRC12869T,Streptomyces pluricolorescens NBRC12808T,and the sequence similarities were all 99.7%.Conclusion:S-BS033004 is an endophytic Streptomyces of Paeonia lactiflora,which has wide antimicrobial spectrum and exploitative potential.