Characterization of copper-resistant bacteria and assessment of bacterial communities in rhizosphere soils of copper-tolerant plants

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2010-01, Vol.44 (1), p.49-55
• Main Authors: He, Lin Yan, Zhang, Yan Feng, Ma, Hai Yan, Su, Le Ni, Chen, Zhao Jin, Wang, Qing Ya, Qian, Meng, Sheng, Xia Fang
• Format: Article
• Language: English
• Subjects: 1-aminocyclopropane-1-carboxylate deaminase; Agronomy. Soil science and plant productions; Bacteria; Bacterial community; bioavailability; Biochemistry and biology; Biological and medical sciences; Brassica napus; Chemical, physicochemical, biochemical and biological properties; copper; Copper mining wasteland; Copper-tolerant plants; DGGE; disease-free plants; DNA; Fundamental and applied biological sciences. Psychology; Heavy metal-resistant rhizobacteria; hydrolases; indole acetic acid; metal tolerance; Microbiology; mine spoil; oil crops; phosphates; Physics, chemistry, biochemistry and biology of agricultural and forest soils; plant growth-promoting rhizobacteria; plants; polluted soils; rapeseed; resistance mechanisms; rhizosphere; ribosomal RNA; siderophores; Soil and water pollution; soil bacteria; Soil science; strain differences
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2009.09.004

Thirteen copper-resistant bacteria were isolated from copper-tolerant plant species growing on a copper mine wasteland. The isolates were identified by 16S rRNA gene sequence analysis and characterized by their resistance to heavy metals and plant growth-promoting characteristics. The assessment of the bacterial communities in the rhizosphere soils of copper-tolerant plants was measured as bands in denaturing gradient gel electrophoresis (DGGE) obtained directly from rhizosphere soil DNA extracts. The isolates were found to exhibit different multiple heavy metal resistance characteristics. Strains SZY6, YJ7 and JYC17 were found to produce indole acetic acid (IAA), siderophore, 1-aminocyclopropane-1-carboxylate (ACC) deaminase or to solubilize phosphate. Root elongation assay conducted on rape under gnotobiotic conditions with strains MT16, JYC17, SZY6, GZC24, and YJ7 demonstrated increase (from 16 to 41%) in root elongation of inoculated rape seedlings compared to the control plants. In the rhizosphere soil samples the DGGE profiles of the direct DNA extracts were similar. The DGGE profiles indicated that there was no significant correlation between the concentration of available copper in the rhizosphere soils and the number of the visible bands in the DGGE pattern.