清除玉米赤霉烯酮菌株的筛选、鉴定及机理初探

Screening, Identification and Mechanism of Bacterial Strains Capable of Eliminating Zearalenone

通过对我国赤霉病高发区田间取样,筛选具有清除玉米赤霉烯酮(Zearalenone,ZEN)活性的菌株.获得2株清除效果较好的细菌A5、D6,其中D6活性较高.通过生理特征分析、16S rDNA序列比对、GC含量及BIOLOG分析等方法,2株菌都被鉴定为红球菌,DNA-DNA同源性分析表明,这2株菌均为Rhodococcus qingshengii.灭活细胞与ZEN共培养,发现细胞无清除ZEN能力,证明A5、D6不具有吸附ZEN的活性;菌液上清液及细胞内容物与ZEN共培养,证明D6菌株中具有清除ZEN的活性成分为胞内蛋白类物质.同时,通过HPLC荧光检测,发现疑似ZEN代谢产物峰.通过筛选获得了2株可通过胞内酶活降解ZEN的红球菌,为生物法清除真菌毒素提供参考.

In this study,the strains capable of degrading Zearalenone(ZEN)were screened through sampling from the agricultural field where gibberellic disease occurred frequently.Two bacteria A5 and D6,showing obvious elimination activity,have been obtained where D6 demonstrated stronger effect.These two strains were identified as Rhodococcus sp.using physiological analysis,BLAST of 16S rDNA sequence,GC content and BIOLOG analysis,the DNA-DNA hybridization result showed that these two strains belonged to Rhodococcus qingshengii.The cells were proved to have no ZEN absorption activity through cultivating the inactivated cells with ZEN;and the active component of D6 strain in ZEN elimination was proved to be intracellular protein by cultivating the bacterial culture supernatant and cellular content together with ZEN.Meanwhile,the peak suspected to be ZEN metabolite was observed with fluorescence detector of HPLC.Two Rhodococcus sp.degrading ZEN via intracellular enzymatic activity were screened and isolated,which provides theoretical evidence for ZEN bio-detoxification.