冬青卫矛内生放线菌YDG17菌株发酵液抑菌活性研究

从冬青卫矛植株中筛选得到一株内生链霉菌YDG17,其发酵液对多种植物病原真菌有较强的抑制作用。室内生物测定结果表明,YDG17菌株发酵液对供试的11种植物病原真菌菌丝生长均有一定的抑制作用,其中对小麦赤霉病菌Fusarium graminearum、番茄灰霉病菌Fulvia fulvum和番茄早疫病菌Alternaria solani的抑制作用最强,EC50值分别为259.98、336.13和100.72 mg/L;对供试的3种植物病原真菌孢子萌发也均有一定的抑制作用,其中对番茄灰霉病菌孢子萌发的抑制作用最强,EC50值为87.84 mg/L。离体子叶法测定结果表明,发酵液原液对番茄灰霉病的保护效果为97.62%,治疗效果为79.63%。盆栽试验结果表明,发酵液原液对番茄灰霉病的保护效果为71.34%,治疗效果为64.23%。捷克八溶剂系统纸色谱测定结果表明,该发酵液的主要活性物质为碱性水溶性抗生素。选用弱酸性离子交换树脂吸附法对YDG17发酵液活性成分进行了初步分离,并对其活性馏分进行ESI-MS/MS分析,表明其活性物质主要为链丝菌素类化合物,该类化合物为首次从植物内生菌中分离得到。

Antifungal Activity of the Fermentation Broth fromEndophytic Streptomyces sp. YDG17 of Euonymus japonicus

A strain of endophytic Streptomyces sp. YDG17 was isolated from the root of Euonymus japonicus. The result of bioassay indicated that the mycelial growth of 11 species of plant-pathogenic fungus could be inhibited in vitro by the broth of YDG17,and the value of EC₅₀ against Fusarium graminearum,Botrytis cinerea and Alternaria solani were 259.98,336.13 and 100.72 mg/L,respectively. The spore germination of 3 species of plant-pathogenic fungus could also be inhibited by the broth of YDG17,and the value of EC₅₀ in the spore germination tests against B.cinerea was 87.84 mg/L.The results also showed that the protective efficacy and curative efficacy of the undiluted fermentation products against B.cinerea were 97.62% and 79.23% on detached cucumber leaves,and were 71.34% and 64.23% on potted cucumber plants,respectively.By comparing with the curves of classical antibiotics in Doskochilova system,the active ingredients in the fermentation were identified as alkaline and water soluble compounds.The broth of YDG17 was isolated by weak acid cation resin and the active fraction was identified as some streptothricins by ESI-MS/MS.