海州香薷(Elsholtzia splendens)根际铜抗性细菌的筛选及生物多样性

Isolation and biodiversity of Copper-resistant bacteria from rhizosphere soil of Elsholtzia splendens

【目的】重金属耐性植物海州香薷根际铜抗性细菌的筛选及生物多样性研究将有助于了解微生物-超富集植物相互关系和植物修复机理、开发微生物-香薷重金属修复新技术。【方法】采用稀释平板涂布法从海州香薷根际筛选铜抗性菌株,测定菌株溶磷和产生吲哚乙酸、铁载体、1-氨基环丙烷-1-羧酸(ACC)脱氨酶的特性,采用16S rDNA限制性酶切多态性分析(amplified rDNA restriction analysis,ARDRA)研究铜抗性细菌的遗传多样性,根据16S rDNA相似性对产ACC脱氨酶的菌株进行了鉴定。【结果】分离纯化到27株抗Cu2+20 mg/L的细菌,所有菌株均能产生吲哚乙酸或其衍生物,44.4%的分离菌株能够分泌高量的铁载体。分离菌株在60%相似性水平上可聚类分为7个群。5株细菌具ACC脱氨酶活性,菌株2EBS12、2EBS13、2EBS15、3EBS11属于不动杆菌属(Acinetobacter),菌株2EBS14属于产碱菌属(Alcaligenes)。【结论】海州香薷根际铜抗性细菌具有丰富多样的生物学特性和遗传多样性,不动杆菌属和产碱杆菌属细菌具ACC脱氨酶活性。

[Objective] Isolation and characterization of rhizosphere copper-resistant bacteria from a copper accumulator plant Elsholtzia splendens were investigated.[Methods] Cultivable Cu-resistant bacteria were isolated by plating and screening from rhizosphere soils of Elsholtzia splendens growing on a copper mine tailing.Bacteria were characterized regarding characteristics that may be relevant for a beneficial plant-microbe interaction—Cu tolerance,phosphate-solubilizing,1-aminocyclopropane-1-carboxylic acid（ACC）deaminase, siderophore and indoleacetic acid production, and further classified by restriction analysis of16S rDNA （ARDRA）. Strains that produced ACC deaminase were identified by 16S rDNA sequence analysis. [ Results] Twenty-seven Cu-resistant strains were isolated from rhizosphere soil of Elsholtzia splendens and classified by ARDRA in different taxonomic groups at the similarity level of 60% . All strains produced IAA or their derivatives, 44.4% of the strait produced a very high level of siderophores, and five strains were able to grow on ACC as the sole nitrogen source. Strain., 2EBS12, 2EBS13, 2EBS15 and 3EBS11 were identified as Acinetobacter, strain 2EBS14 was essentially consistent Alcaligenes [ Conclusion] Cu-resistant rhizobacteria isolated from Elsholtzia splendens have abundant characteristics relative to promoting plant growth and genetic diversity, rhizobacteria Acinetobacter sp. and Alcaligenes sp. contained ACC deaminase activity.