| 摘要: |
| 【目的】明确菌株Y-19的种属及其异菌脲降解特性，挖掘青藏高原地区异菌脲高效降解微生物资源，以期解决西藏地区大棚土壤环境中异菌脲的残留问题，确保该地区大棚种植土壤及蔬菜的质量安全。【方法】以异菌脲高效降解菌株Y-19为研究对象，采用多相分类方法开展该菌株的种属鉴定，采用GC-ECD法和GC-MS法分析该菌株的异菌脲降解途径及降解特征，分别以异菌脲初始质量浓度、温度、pH值、接种量和NaCl质量分数等为因子，探究该菌株的最佳降解环境条件，并采用比较基因组学挖掘该菌株的异菌脲降解基因。【结果】多相分类鉴定结果表明，菌株Y-19为烟碱拟节杆菌（Paenarthrobacter nicotinovorans），其能够将异菌脲先降解为N-(3,5-二氯苯基)-2,4-二氧代咪唑烷和异丙基氨基甲酸，其次再将N-(3,5-二氯苯基)-2,4-二氧代咪唑烷降解为N-［［(3,5-二氯苯基)氨基］羰基］甘氨酸，最后将N-［［(3,5-二氯苯基)氨基］羰基］甘氨酸降解为3,5-二氯苯胺和氨基甲酸。菌株Y-19的最佳异菌脲降解环境条件为：温度25 ℃、pH 7.0，NaCl质量分数0.0%～1.0%、接种量5%和异菌脲初始质量浓度100 mg/L。在最佳条件下菌株Y-19可在14 h完全降解100 mg/L异菌脲，异菌脲降解率为100%，最终生成48.8 mg/L 3,5-二氯苯胺。菌株Y-19含有高度相似的异菌脲降解基因ipaH，ddaH和duaH，上述基因编码的水解酶能够使异菌脲及其降解产物结构中的酰胺键（―CO―N＝，包括肽键―CO―NH―）发生水解反应。【结论】烟碱拟节杆菌（Paenarthrobacter nicotinovorans）Y-19是降解异菌脲效率较快的菌株，节杆菌属（Arthrobacter）和拟节杆菌属（Paenarthrobacter）可能是参与异菌脲降解为3,5-二氯苯胺的主要细菌种类。 |
| 关键词: 异菌脲 农药残留 3,5 二氯苯胺 降解特性 拟节杆菌属 降解途径 降解基因 |
| DOI：DOI:10.13207/j.cnki.jnwafu.2024.11.013 |
| 分类号: |
| 基金项目:国家自然科学基金项目（32060025）；西藏财政本级农口部门预算项目（XZNKYZBS-2023-C-001） |
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| Identification and degradation characteristics of an iprodione-degrading strain Y-19 |
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PAN Hu1,2
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1.Institute of Agricultural Quality Standard and Testing,Tibet Academy of Agricultural and Animal Husbandry Sciences,Lhasa,Tibet 850032,China;2 Agricultural and Livestock Products Engineering Technology Research Center of Tibet Autonomous Region,Lhasa,Tibet 850032,China
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| Abstract: |
| 【Objective】This study identified the species of strain Y-19,determined its iprodione-degradation characteristics and explored high-efficient iprodione-degrading microorganisms on the Qinghai-Tibet Plateau to solve the iprodione-residue problem in soil environment and ensure the quality and safety of greenhouse soil and vegetables.【MethodThe strain Y-19 was classified using polyphasic classification methods.The degradation pathway and characteristics were analyzed by gas chromatography-electron capture detection (GC-ECD) and gas chromatography-mass spectrometer (GC-MS).Initial iprodione concentration,temperature,pH value,inoculation amount and NaCl concentration were investigated to formulate optimal degradation environmental factors.The iprodione-degrading genes of strain Y-19 were dug by comparative genome analysis.【Result】Strain Y-19 was identified as Paenarthrobacter nicotinovorans by polyphasic classification technology.It could firstly decompose iprodione into N-(3,5-dichlorophenyl) -2,4-dioximidazolidine and isopropyl carbamate.Then,N-(3,5-dichlorophenyl)-2,4-dioximidazolidine could be decomposed to N-［［(3,5-dichlorophenyl)amino］carbonyl］glycine.Finally,N-［［(3,5-dichlorophenyl)amino］-carbonyl］glycine was degraded to 3,5-dichloroaniline and carbamic acid.The optimal iprodione-degrading conditions of strain Y-19 were 25 ℃,pH 7.0,NaCl 0.0%-1.0%,inoculation amount 5% and initial iprodione concentration 100 mg/L.Under these conditions,100 mg/L of iprodione could be degraded within 14 h and generated 48.8 mg/L 3,5-dichloroaniline.Strain Y-19 had highly similar ipaH,ddaH and duaH genes with other iprodione-degrading bacteria.The hydrolytic enzymes encoded by above genes could hydrolyze amide bonds (―CO―N＝,including ―CO―NH―) in iprodione and its degradation products.【Conclusion】Paenarthrobacter nicotinovorans Y-19 is an efficiently iprodione-degrading bacteria.Arthrobacter spp. and Paenarthrobacter spp. may be main bacterial species to degrade iprodione to 3,5-dichloroaniline. |
| Key words: iprodione pesticide residue 3,5 dichloroaniline degrading characteristics Paenarthrobac ter degradation pathway degradation genes |
