活性内生真菌EZG0807的鉴定及其生物学特性研究

Identification and Biological Characteristics of an Active Endophytic Fungus EZG0807

从传统中药温莪术根部分离出一株活性内生真菌EZG0807,采用分子生物学与形态学观察相结合的方法对其进行鉴定。通过PCR扩增该菌ITS区域并在NCBI中进行同源性分析,构建系统发育树,结合形态学观察,鉴定其为串珠赤霉菌Gibberella moniliformis,是一种兼性内生真菌,既是植物和昆虫病害的病原体,又能作为内生真菌促进宿主植物的生长;为了更好地了解和利用活性菌株EZG0807,对其进行了生物学特性及发酵条件优化的研究。该菌除对半乳糖和（NH4）2SO4利用度较差外,能利用多种常见的培养基;其生长温度范围为15～35℃,最适生长温度为30℃;菌株生长pH范围为4.0～10.0,最适pH为7。根据菌株EZG0807的生长特性及前期单因素实验结果,经响应面优化后的发酵条件为发酵温度28.72℃,初始pH值6.76,发酵时间10.02 d,测得其发酵液对普通变形杆菌的抑菌圈直径为25.6 mm,比优化前提高24.9%。熟悉该菌株的生长培养条件和营养需求,可为后续研究其代谢产物奠定基础。

An active endophytic fungus EZG0807 isolated from the Chinese traditional medical plant Curcuma wenyujin was identified as Gibberella moniliformis through the molecular biology technique combined with morphology. It is a facultative endophytic fungus, which can not only induce the disease in plants and insects, but also stimulate the growth of host plant. In the other hand, the researches about the biological characters and fermentation conditions of this active fungus were carried out. It could use a variety of media except galactose and （NH4）2SO4and grew in the range of 15～35℃ and pH 4.0～10.0. The optimum growth temperature and pH were 30℃ and 7, respectively. Based on the fungal characteristics and previous one-factor experiment, the optimal fermentation condition was 28.72℃ for the temperature, 6.76 for initial pH and 10.02 d performed by the Response Surface Methodology. Under this optimal condition, the inhibition zone of fungal fermentation broth against Proteus vulgaris reached 25.6 mm, which was improved by 24.9%, making a foundation for further study on its metabolites.