产纳他霉素生防菌A01和A02与已知产生菌的RAPD比较

为了明确自主分离的天然抗真菌活性产物——纳他霉素产生菌A01和A02与已知纳他霉素产生菌的遗传相似性,采用RAPD技术对这2株菌和3个产纳他霉素的标准菌株进行了比较分析。利用筛选出的7个随机引物对5个菌株的PCR扩增共得到154条清晰稳定的DNA条带,其中同源性条带86条,多态性条带68条,分别占总条带数的55.8%和44.2%,平均每个引物扩增出9.7个多态性条带,得到了丰富的DNA指纹图谱。所得数据经NTSYS pc 2.10e软件聚类分析,表明5个菌株间的遗传距离为0.0991~0.4738,其中A02与其它菌株间的遗传距离均较远。结合前期的分类研究结果,确证了菌株A02为新的纳他霉素产生菌。

Comparison of the Genetic Similarity between Natamycin-producing Strains A01, A02 and Three Standard Ones by RAPD

Antagonistic strains A01 and A02 were independently isolated from the soil in suburbs of Beijing,and identified preliminarily as Streptomyces lydicus.Recent research showed the two strains were able to produce natamycin,an antifungal metabolite strongly inhibitive against plant pathogenic fungi,including Botrytis cinerea,Alternaria solani,Fusarium oxysporum f.sp. conglutinans,etc.In this paper,genetic similarities between the two strains and three reported standard natamycin producing strains were analyzed with random amplified polymorphic DNA（RAPD）.Seven high-repeatable primers with good polymorphism were screened from 20 primers and used for PCR amplification of five natamycin-producing strains mentioned above.154 clear and stable DNA bands were obtained totally,including 86 homologous bands（55.8% of the total bands） and 68 polymorphic bands（44.2% of the total）.On average,each primer amplified 9.7 polymorphic fragments,resulting in a rich DNA fingerprinting.Cluster analysis demonstrated that the genetic distances between the five strains ranged from 0.0991 to 0.4738,and there were greater genetic distances between strain A02 and the other four strains.The result confirmed that A02 was a new strain producing natamycin.