异菌脲降解菌Y-19的鉴定及其降解特性  

Identification and degradation characteristics of an iprodione-degrading strain Y-19

作　　者：潘虎 PAN Hu(Institute of Agricultural Quality Standard and Testing,Tibet Academy of Agricultural and Animal Husbandry Sciences,Lhasa,Tibet 850032,China;Agricultural and Livestock Products Engineering Technology Research Center of Tibet Autonomous Region,Lhasa,Tibet 850032,China)

机构地区：[1]西藏自治区农牧科学院农业质量标准与检测研究所,西藏拉萨850032 [2]西藏自治区农畜产品工程技术研究中心,西藏拉萨850032

出　　处：《西北农林科技大学学报（自然科学版）》2024年第11期121-131,共11页Journal of Northwest A&F University(Natural Science Edition)

基　　金：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)。

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。【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.【Method】The 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.

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 

分 类 号：Q939.96[生物学—微生物学]