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

Abstract:

Abstract: [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 of 16S 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 7 different taxonomic groups at the similarity level of 60%. All strains produced IAA or their derivatives, 44.4% of the strains produced a very high level of siderophores, and five strains were able to grow on ACC as the sole nitrogen source. Strains 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.