菲降解菌Pseudomonas sp. JM2-gfp细胞特性对生物膜形成能力的影响及其在植物根表的定殖  

Effect of characteristics of phenanthrene-degrading bacteria Pseudomonas sp. JM2-gfp on biofilm formation and its colonization on plant root surface

作　　者：高晓蓉[1] 朱丽晖 周玉嫚 GAO Xiaorong;ZHU Lihui;ZHOU Yuman(School of Bioengineering,Dalian University of Technology,Dalian,Liaoning 116024,China)

机构地区：[1]大连理工大学生物工程学院,辽宁大连116024

出　　处：《微生物学通报》2021年第11期4019-4029,共11页Microbiology China

基　　金：国家自然科学基金(21876017)。

摘　　要：【背景】多环芳烃是农田土壤中的主要有机污染物,可通过作物根系进入食物链威胁人类健康。采用高效降解菌在植物根际形成生物膜是一种经济可行的生态阻控策略,而细菌细胞特性是影响其表面粘附并进行初始成膜的关键。【目的】探究菲高效降解菌Pseudomonassp.JM2-gfp的细胞特性对自聚集成膜过程的影响,观察其在小麦根表定殖成膜情况,为在土壤-根际系统中构建阻控屏障提供理论依据。【方法】采用培养皿培养、结晶紫染色、接触角测量(Contact Angle Measurement,CAM)及定量方法测定JM2-gfp菌株细胞特性,采用植物液体培养法形成生物膜,采用激光共聚焦显微镜(Confocal Laser Scanning Microscope,CLSM)、扫描电子显微镜(Scanning Electron Microscope,SEM)观察和分析生物膜的结构特征。【结果】菌株Pseudomonas sp. JM2-gfp生有鞭毛结构及疏水性细胞壁,并具备较强的运动能力、初始粘附率和自聚集能力。JM2-gfp菌株具有良好的成膜及降解能力,48 h菲降解效率是浮游态菌株的2.5倍。成膜过程呈现明显的周期性变化,2 d时生物膜量达最大值。2 d内生物膜厚度约为32.8μm,生物膜上分泌多种胞外基质物质(Extracellular Polymeric Substances,EPS),其中碳水化合物和蛋白质含量分别为74.68μg/mL和211.9μg/mL。小麦根系与菌液共培养4 d后,JM2-gfp菌株可在根表形成稳定的生物膜,并进一步定殖到根和茎、叶组织内部。【结论】菲胁迫下,Pseudomonassp.JM2-gfp降解菌易于在载体表面附着聚集形成生物膜,降解能力也随之增强,其在植物根表定殖成膜的结果为阻控土壤有机污染物进入作物体内提供了一种新的技术策略。[Background] Polycyclic aromatic hydrocarbons(PAHs) accumulated in agricultural soils are threatening human health and ecosystem via food chain. The strategy to impede PAHs entrance by biofilm formation of degrading bacteria on the root surface is economically feasible. Bacteria cell properties are the key factors determining its adhesion and initial formation of the biofilm. [Objective] Our study aims to investigate the biofilm formation process and identify the features of a phenanthrene degrading bacterium Pseudomonas sp. JM2-gfp influencing on the cell adhesion and the biofilm formation, to observe its colonization on the wheat root surface, and finally to provide references for building a control barrier in the soil-rhizosphere system. [Methods] Methods of petri dish culture observation, crystal violet stain, and contact angle assay were used to determine the cell characteristics of JM2-gfp. Hydroponic culture of plant was used to generate the biofilm formation. The structural features of the biofilm were observed and analyzed by a confocal laser scanning microscope(CLSM) and scanning electron microscope(SEM).[Results] The strain Pseudomonas sp. JM2-gfp has a flagella structure and hydrophobic cell wall, as well as strong motility, initial adhesion, self-aggregation ability. It showed good biofilm-forming abilities and phenanthrene-degrading performance. Compared with planktonic bacteria, our biofilms can degrade phenanthrene within 48 hours by 2.5 times. The film formation process presented obvious periodic changes, and the amount of the biofilm reached the maximum at the second day. The thickness of the biofilm within 2 days was about 32.8 μm, and a variety of extracellular polymeric substances(EPS) were secreted on the biofilm, containing carbohydrate at the concentration of 74.68 μg/mL and protein 211.9 μg/mL,respectively. After 4 days of co-cultivation of wheat roots and JM2-gfp, a stable biofilm was formed by JM2-gfp on the root surface, and further colonized the roots, stems and leaf tissues. [Conc

关 键 词：菲降解菌 细胞特性 生物膜 根表 定殖 

分 类 号：X592[环境科学与工程—环境工程] X172