合欢内生菌H8的分离、鉴定及其抗菌代谢物质研究

摘要

An endophytic bacteria H8 was isolated from the leaves of the Chinese medicinal plant Albizzia julibrissin Durazz.,in order to find novel antimicrobial activity compounds .The methods of dual culture and agar diffusion assay were used ,the result showed that the strain H 8 had strong antifungal activity against growth of six pathogens Valsa ceratosperma,Botryosphaeria dothidea,and so on.The inhibition zone diameter ranged from 20.5 to 34 .5 mm depending on the microorganism being tested .According to the characteristics of morphology ,physiological characterization and the comparison of 16S rDNA sequence,strain H8 was identified as was Bacillus subtilis.The an-tifungal extracts were fractionated and purified on liquid-liquid extraction ,thin-layer chromatography and silica gel chromatography .From the culture extracts of H8,two active components were silylated ,then twenty-eight compounds were identified as fatty acids ,aromatic acids and cyclic dipeptides based on gas chromatograph-mass spectrometer .%为了寻找结构新颖，高效的农用抗菌活性物质，以药用植物合欢叶为试验材料，分离筛选出一株内生细菌H8。采用对峙培养法与琼脂扩散法进行抑菌试验，结果表明：H8菌株、发酵液、无菌发酵液及其活性组分对苹果腐烂病菌、苹果轮纹病菌等6种供试植物病原菌均具有较强的抑菌活性，抑菌带宽度可达20．5～34．5 mm。经形态观察、生理生化试验和16S rDNA系统进化分析，鉴定其为死谷芽孢杆菌（Bacillus vallismortis）。采用液-液萃取、薄层层析及硅胶柱层析，对内生菌H8的代谢液提取分离，得6个组分，对抑菌活性高的2个组分硅烷化衍生后，经GC-MS检测，确定代谢液中有脂肪酸、芳香酸、环二肽等28种活性化合物。