德国鸢尾组培快繁过程中内生菌的分离、鉴定及控制药剂筛选

Isolation,Identification and Screening of Endophyte Fingicides for Disease Control during Tissue Culture of German Irises

【目的】在德国鸢尾的组培过程中,内生菌引起的污染制约着其进行快速繁殖工厂化育苗,针对引起德国鸢尾组培苗污染的内生菌进行分离、鉴定,研究比较6种常用药剂对该菌株的抑制效果,筛选出最佳防治药剂,为德国鸢尾组培快繁过程中有效控制内生菌污染提供科学依据。【方法】采用NA培养基分离纯化菌株(115325),通过形态特征观察、生理生化试验及16S r DNA序列同源性分析,对其进行分类鉴定。采用纸碟抑菌圈法测定6种常用药剂对供试菌株的抑制效果。【结果】供试菌株115325的形态特征,及生理生化指标与表皮葡萄球菌(Staphylococcus epidermidis)基本相同。16S r DNA序列分析表明,该菌株与解糖葡萄球菌S.saccharolyticus(L37602)进化关系最为密切,聚在同一个系统发育分支,与表皮葡萄球菌的同源性最高,为99.86%。室内药剂筛选结果表明,头孢菌素和庆大霉素对供试菌株的抑制作用最强。【结论】综合形态学特征、生理生化特性及16S r DNA序列分析结果,供试菌株115325被鉴定为表皮葡萄球菌。头孢菌素和庆大霉素可作为抑制德国鸢尾组培苗内生菌污染的首选药剂。

[ Objective] During tissue culture of German irises, Endophytic bacteria pollution is the key problem of restricting them for rapid propagation factory nursery. For that reason, this project aims to segregate and identify endophytic bacteria that might lead to tissue culture explants pollution, and the inhibition of 6 kinds of commonly used agents on the strain effect will be compared so as to select the best preventive agent. That will provide a scientific basis for effective control of endophytic bacteria pollution during its rapid propa- gation. [ Method] The strain （115325 ） has been segregated and purified using NA medium and the endophyt- ic bacteria were been classified and identified by morphology observation, physiological and biochemical test, and 16S rDNA sequence homology analysis. Inhibitory effects of 6 kinds of commonly used chemicals on the tested strains were determined by the method of paper disc bacteriostatic circle. [ Result ] The strain （115325） of morphology characteristics and physiological and biochemical indicators were basically the same as Staphylococcus epidermidis. The results of 16S rDNA sequence homology analysis showed that the strain and saccharolyticus（L37602） had mostly close relation in the evolution, belonging to the same phylogenetic branch. And S. staphylococcus epiderrnidis had the highest homology, at 99.86%. Indoor medicament screen- ing results showed that the cephalosporins and gentamicin had the strongest inhibitory effect on strains. [ Con- clusion] The comprehensive analysis results of morphological characteristics, physiological and biochemical characteristics and 16S rDNA sequence, 115325 strains have been identified as Staphylococcus epidermidis. Cephalosporin and gentamicin can be used as the preferred agents to inhibit endophytic bacterial contamination of the German iris plantlets.