尼古丁降解菌SCUEC1菌株的分离及其降解基因

Isolation and gene characterization of a nicotine-degradation strain Agrobacterium tumefacience SCUEC1

【目的】分离并鉴定1株具有尼古丁降解能力的细菌,研究其尼古丁降解特性并对其降解基因进行分析,为尼古丁微生物降解提供基础。【方法】从烟草种植地土壤中分离1株具有尼古丁降解能力的细菌,通过16S r RNA基因和生理生化特性对该菌株进行鉴定,检测该菌株尼古丁降解率与生长量的关系,并进一步对该菌株进行尼古丁浓度耐受性测定,采用高通量测序技术对菌株进行全基因组测序,BLAST比对分析尼古丁降解相关基因。【结果】筛选到1株具有尼古丁降解能力的细菌,经鉴定命名为根癌土壤杆菌(Agrobacterium tumerficience)SCUEC1菌株,根癌土壤杆菌SCUEC1菌株尼古丁降解率可达到94.81%,该菌株在尼古丁浓度为0.50–5.00 g/L范围内生长良好且有较高的尼古丁降解能力。对根癌土壤杆菌SCUEC1菌株全基因组序列进行BLAST比对分析,推测该菌株的尼古丁降解代谢途径与中间苍白杆菌SYJ1菌株的尼古丁降解途径相似。【结论】本研究揭示了Agrobacterium tumerficienceSCUEC1菌株具备尼古丁降解特性,初步推测出尼古丁降解相关基因和降解代谢途径,为尼古丁微生物降解提供基础。

[Objective] The aim of this study was to identify bacterial species capable of degrading nicotine, and to characterize related genes. [Methods] One bacterial strain with the ability to degrade nicotine was screened from tobacco field soil by using nicotine as the sole carbon source. Using phylogenetic analysis of its 16S rRNA gene, together with physiological and biochemical characteristics, we identified this strain as Agrobacterium tumefacience SCUEC1. We determined its association of degradation rate with its growth rate, and its tolerance to nicotine. Also, the genome was sequenced using high throughput sequencing technology, and the nicotine metabolic pathway of SCUEC1 strain was analyzed by bioinformatics tools. [Results[ Nicotine degradation rate of SCUEC1 reached 94.81%. The strain tolerated nicotine with the concentration from 0.50 g/L to 5.00 g/L. Its metabolic pathway of nicotine degradation appeared similar to that of Ochrobactrum sp. strain SJY1. [Conclusion] Agrobacterium tumerficience SCUEC 1 degraded nicotine. These findings provide a theoretical basis for biodegradation of nicotine.