拟康宁木霉T-51菌株发酵液对灰葡萄孢的抑菌活性

拟康宁木霉菌株T-51是从土壤中分离得到的一株优秀生防菌株,在前期的研究与应用中表现出对番茄灰霉病的良好防效。本文研究了T-51菌株的PDB发酵液对灰葡萄孢的抑菌活性,结果表明T-51发酵液在0.5%的低浓度下的抑菌率达到52.1%,与高浓度(10%)发酵液的抑菌率(59.7%)没有显著差异。当发酵液浓度下降为0.05%时失去抑菌活性。T-51摇培至第5天时的发酵液的抑菌活性稳定。T-51发酵液中的抑菌物质对高温不敏感,沸水浴处理10 min后抑菌活性没有明显降低。T-51发酵液pH为3.3,呈酸性,当调节pH至7时,发酵液抑菌活性从57.89%下降到46.61%。T-51发酵液能够显著抑制灰葡萄孢侵染番茄叶片后产生的病斑大小,接种后叶片病斑直径比对照减小53.9%。

Antifungal activity of Trichoderma koningiopsis T-51 cultural filtrate against Botrytis cinerea

Trichoderma koningiopsis T-51,a promising biological control agent against gray mold caused by Botrytis cinerea,was isolated from soil.The antifungal activity of the cultural filtrates(CF)of isolate T-51 in potato dextrose broth(PDB)was determined.The results showed that 0.5%of T-51 CF showed high antifungal activity against B.cinerea,with an inhibition percentage of 52.1%,not significantly(P>0.05)different from that in the treatment with 10%CF(59.7%).The T-51 CF lost the antifungal activity at the concentration of 0.05%.The antifungal activity of the T-51 CF did not continue increase when incubated for more than 5 days.The antifungal metabolites of T-51 appeared thermostable,as the CF in the treatment at 100℃for 10 min still showed antifungal activity.Ambient pH value greatly affected the antifungal activity of the T-51 CF:when the pH value of the CF was adjusted from 3.3 to 7.0 with NaOH,the inhibition percentage was decreased from 57.89%to 46.6%.The CF of T-51 showed strong inhibition against infection by B.cinerea on tomato leaves,the size of the average leaf lesion was decreased by 53.9%by the T-51 CF compared to that in the control.