2株放线菌的抗菌活性及分类学地位

旨在对2株放线菌HD-103和HD-109的抗菌活性和发酵液稳定性进行比较分析，并明确2株菌的分类学地位。以13种植物病原真菌为靶标菌，利用琼脂柱法分析2株生防菌的抗菌谱；以尖孢镰刀菌(Fusariumoxysporumf.sp.glycines)为指示菌，利用杯碟法检测2株生防菌发酵液的热稳定性、pH稳定性及紫外稳定性，并进行比较分析；在此基础上采用多相分类法对2株菌进行鉴定。研究结果显示：2株菌的抗真菌谱均较广，其中HD-103对禾谷镰刀菌(Fusariumgraminearumf.sp.Glycines)的抑制效果最显著，抑菌圈直径达到23.7mm，HD-109对烟草赤星病菌(Alternariaalternate)抑制效果最好，抑菌圈直径达25.0mm；HD-103的抗菌活性物质较HD-109的活性物质更为稳定；分类学鉴定结果表明，菌株HD-103与HD-109为微白黄链霉菌(Streptomycesalbidoflavus)的2个菌株。菌株HD-103与HD-109能够抑制多种植物病原真菌，其发酵液具有较好的热稳定性和酸碱稳定性，具有开发为新型生物农药的潜力。

Antifungal activity and taxonomic status of two actinomycetes

Objective] The objectives of this work were to comparative analysis the antibacterial activity between strain HD-103 and strain HD-109 and the stability of fermentation broth of the two actinomycetes against pathogenic fungi in vitro, and to identify their taxonomic status. Method] 13 kinds of plant pathogenic fungus were used as target microorganisms, antifungal spectrums of the two strains against target fungus was determined by measuring the diameter of inhibition zone. The thermostability, pH stability and UV resistance of fermentation broth of the two strains were detected and compared through cylinder plate method, and multiple classification method was used to clarify and definite their taxonomic position. Result] The experiment results showed that the two strains have broad anti-fungal spectrum for their inhibiting growth of 10 pathogenic fungus, wherein strain HD-103 has the best activity of inhibiting Fusarium graminearum f. sp. glycines, the diameter of inhibition zone reaches 23.7 mm; strain HD-109 has the best activity against Alternaria alternata, the diameter of inhibition zone reaches 25.0 mm. The antimicrobial active substances produced by strain HD-103 are more stable than that of strain HD-109. Evaluation results of taxonomy showed that HD-103 and HD-109 should belong to Streptomyces albidoflavus, and probably are two different variants of S. albidoflavus Conclusion] The two strains of Streptomyces albidoflavus have great disease suppression effects in vitro, therefore they could be develop a potential biological control agent against plant fungal pathogens, and have great value of application.