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期 刊 ：植物保护学报 2006年

关键词：内生真菌；终极腐霉；立枯丝核菌；矮棒曲霉；抑菌活性；

Keywords:Endophytic fungi, Pythium ultimum, Rhizoctonia solani, Aspergillus clavatonanicus, antifungal activity,

摘 要 ：从南方红豆杉中分离到549株内生真菌,以终极腐霉Pythium ultimum、立枯丝核菌Rhizoctonia solani为靶标菌进行抗菌活性的筛选。结果表明,对终极腐霉、立枯丝核菌的半抑制稀释倍数(ID₅₀)在10以上的活性菌株分别为20株(占总菌株的3.6%)和15株(占总菌株的2.8%)。其中矮棒曲霉Aspergillus clavatonanicus菌株F0028对这两种病原菌的活性最高(对终极腐霉、立枯丝核菌的ID₅₀分别为278±15.0、108±18.6)。进一步研究表明,F0028发酵液在pH值为1.0~7.0之间均有较强的抑菌活性;经高温高压处理后抑菌活性仍达到了对照的(65±3.8)%。发酵液经高效液相色谱纯化得到5种化合物,活性测定表明,5种化合物对终极腐霉、立枯丝核菌均有不同程度的抑制作用,半抑制浓度(EC₅₀)在7.0~45 μg/mL之间。

Abstract:A total of five hundred and forty-nine isolates of endophytic fungi isolated from Taxus mairei were screened for the bioactivity targeted against Pythium ultimum and Rhizoctonia solani. Of 549 isolates, 20 isolates (about 3.6% of the total isolates) showed significant activity against P.ultimum and 15 isolates (about 2.8% of the total isolates) against R.solani with ID₅₀ beyond 10. The isolate F0028, which has the highest inhibitory rate against P.ultimum (ID₅₀ of 278±15.0) and R.solani (ID₅₀ of 108±18.6) was identified as Aspergillus clavatonanicus. Its crude fermentation broths also showed strong inhibitory activity at pH value range from 1.0 to 7.0 and retained certain inhibitory activity of (65±3.8)% when autoclaved. Five compounds were isolated from the strain F0028 crude fermentation broths by HPLC. The results of bioassays revealed that all the five compounds have certain inhibitory activity with EC₅₀ between 7.0 and 45 μg/mL against two pathogenic fungi.

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