一株镰刀菌酸高效降解菌的分离与鉴定及降解特性研究

Isolation, identification and degradation characteristics ofa fusaric acid degrading bacterium

为给镰刀菌酸(Fusaric Acid,FA)污染土壤和饲料脱毒提供菌株资源,从发生枯萎病的香蕉根际土里采集土壤样品,通过富集培养,分离出一株FA降解菌FAD1.通过菌落形态特征观察、16S rDNA基因序列比对,菌株FAD1鉴定为分枝杆菌属(Mycolicibacterium sp.),将其接种至以FA作为唯一碳(C)或氮(N)源培养基中观察生长特性,通过高效液相色谱法(High Performance Liquid Chromatography,HPLC)和植物活体测试评估FAD1对FA的降解效果.研究表明,FAD1在以FA作为唯一C或N源的培养基中均可生长,其中在以FA作为唯一N源和额外添加C、N源培养基中对FA的降解效果最佳.在HPLC检测结果表明,FAD1在含有FA的培养基中培养至衰退期,FA降解率高达89%.植物活体测试显示,番茄(Solanum lycopersicum)幼苗在含有FA且未经FAD1发酵的培养基中浸泡40 h后失去膨压、叶面失水死亡,而其余经FAD1发酵后的处理组均存活.综上所述,FAD1能够在以FA作为唯一C、N源的培养基中生长,对FA具有一定的降解能力,在防治FA对植物、动物和微生物的危害方面具有一定的应用价值.

In order to provide strain resources for detoxification of fusaric acid(FA)-contaminated soil and feed,soil samples were collected from banana rhizosphere soil in the field where fusarium wilt occurred,An FA degrading bacterium FAD1 was isolated by enrichment culture.Through the observation of colony morphological characteristics and 16S rDNA gene sequence alignment,the strain FAD1 was identified as Mycobacterium sp.,FAD1 was inoculated into the medium with FA as the sole carbon(C)or nitrogen(N)source to observe its growth characteristics.The degradation effect of FAD1 on FA was evaluated by high performance liquid chromatography(HPLC)and plant in vivo test.The results showed that FAD1 could grow in the medium with FA as the sole source of C or N,and the degradation effect of FA was the best in the medium with FA as the sole source of N or additional sources of C and N.The HPLC results showed that the degradation rate of FA was up to 89%when FAD1 was cultured in FA containing medium until the decline phase.Plant in vivo test showed that tomato(Solanum lycopersicum)seedlings lost turgid pressure and died of leaf water loss after soaking in MMF medium containing FA without FAD1 fermentation for 40 h,while seedlings treated after FAD1 fermentation survived.In conclusion,FAD1 can grow in the culture medium with FA as the sole source of C and N.FAD1 can degrade FA to a certain degree,which has a application value in preventing the harm of FA to plants,animals and microorganisms.