| 李佳颖,李昂,朱展鹏,黄应群,唐杨臻郅,郭文龙,袁芳,许小霞,金丰良,2026,全基因组分析根癌农杆菌At_42菌株降解烟碱的机制[J].环境昆虫学报,(4):1227-1241 |
| 全基因组分析根癌农杆菌At_42菌株降解烟碱的机制 |
| Genome-wide analysis of the nicotine degradation mechanism in Agrobacterium tumefaciens strain At_42 |
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| DOI：10.3969/j.issn.1674-0858.2026.04.23 |
| 中文关键词: 烟碱 分子对接 MS/MS At_42菌株 |
| 英文关键词:Nicotine molecular docking MS/MS strain At_42 |
| 基金项目:永州市烟草公司科技项目计划（2023）16号；国家自然科学基金（32172498，31972345） |
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| 中文摘要: |
| 【目的】为解决烟草上部烟叶中烟碱含量偏高及烟碱环境污染治理问题，本研究基于实验室前期分离获得的1株高效烟碱降解菌-根癌农杆菌Agrobacterium tumefaciens At_42，利用基因组学方法深入解析其烟碱降解机制。【方法】通过平均核苷酸一致性分析（Average nucleotide identity，ANI）、共线性比对、泛基因组分析、分子对接及RT-qPCR，对At_42进行了分类鉴定，并在基因水平上研究了烟碱代谢途径。同时，利用MS/MS技术检测了At_42降解烟碱的代谢产物。【结果】泛基因组分析显示At_42拥有13 296个基因家族，其中核心基因家族为1 301个。共线性分析表明，At_42与A. tumefaciens S33的烟碱降解基因簇高度同源，鉴定出10个同源基因。分子对接结果显示，At_42中的NdhA和NdhB蛋白能与尼古丁结合，而Hsh蛋白则能与6-Hydroxy-3-succinoylpyridine结合。RT-qPCR检测发现，At_42中关键的烟碱代谢基因（NdhA、NdhB、Pno、Nfo、Hsh、Iso、Ami、Hpo、Hno）在烟碱诱导下均显著上调表达。MS/MS分析鉴定出6-羟基-N-甲基肌胺、2,5-二羟基吡啶、6-羟基假氧尼古丁和马来酸盐等代谢产物。其中，6-羟基-N-甲基肌胺和6-羟基假氧尼古丁通过吡啶途径生成，而6-羟基假氧尼古丁和马来酸盐则源自吡咯途径。【结论】基于上述代谢检测与基因组生物信息学分析结果，预测At_42通过通过吡咯烷-吡啶途径降解尼古丁。本研究评估了菌株At_42在环境烟碱污染修复中的应用潜力，在烟草农业和环境治理领域具有重要价值。 |
| 英文摘要: |
| 【Aim】To address the issue of high nicotine content in upper tobacco leaves and the remediation of environmental nicotine pollution, this study employed genomic approaches to investigate the nicotine degradation mechanism of Agrobacterium tumefaciens At_42, a highly efficient nicotine-degrading strain previously isolated in our laboratory.【Methods】Classification of At_42 and its nicotine metabolic pathway at the genetic level were studied using Average Nucleotide Identity (ANI) analysis, synteny alignment, pan-genome analysis, molecular docking, and RT-qPCR. Concurrently, metabolites resulting from nicotine degradation by At_42 were analyzed using MS/MS technology.【Results】The results demonstrated that ANI analysis confirmed At_42 as A. tumefaciens. Its complete genome size is 5.86 Mb,with a GC content of 59.24%, encoding 5 770 predicted genes. Pan-genome analysis revealed that At_42 possesses 13 296 gene families, of which 1 301 are core gene families. Synteny analysis demonstrated a high degree of homology between the nicotine degradation gene cluster of At_42 and that of A. tumefacien S33, with 10 homologous genes identified. Molecular docking results indicated that the NdhA and NdhB proteins in At_42 can bind to nicotine, while the Hsh protein can bind to 6-Hydroxy-3-succinoylpyridine (Hsp). RT-qPCR detection revealed significant upregulation of key nicotine metabolic genes (NdhA, NdhB, Pno, Nfo, Hsh, Iso, Ami, Hpo, Hno) in At_42 in response to nicotine induction. MS/MS analysis identified metabolites including 6-Hydroxy-N-methylmyosmine,2,5-Dihydroxypyridine, 6-Hydroxy-pseudo-oxynicotine, and Maleate. Among these, 6-Hydroxy-N-methylmyosmine and 6-Hydroxy-pseudo-oxynicotine are generated via the pyridine pathway, while 6-Hydroxy-pseudo-oxynicotine and Maleate are derived from the pyrrolidine pathway.【Conclusion】Based on the metabolite detection and genomic bioinformatics analysis results, At_42 is predicted to degrade nicotine through a pyrrolidine-pyridine pathway. This study evaluated the application potential of strain At_42 for the remediation of environmental nicotine pollution, demonstrating considerable value in the fields of tobacco agriculture and environmental management. |
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