Genetic diversity and characterization of heavy metal-resistant-endophytic bacteria from two copper-tolerant plant species on copper mine wasteland

Bioresour Technol. 2010 Jan;101(2):501-9. doi: 10.1016/j.biortech.2009.08.011. Epub 2009 Sep 16.

Abstract

The diversity of endophytic bacteria from the copper-tolerant species Elsholtzia splendens and Commelina communis was evaluated by using cultivation and cultivation-independent techniques. Phylogenetic analysis based on 16S rDNA sequences showed that the Cu-resistant isolates belonged to three major phylogenetic groups: Firmicutes, Actinobacteria and Proteobacteria. Bacillus and Acinetobacter were predominant among the Cu-resistant isolates. Sequence analysis from the 16S rDNA clone libraries of the two plant roots revealed sequences of Alpha-, Beta-, Gamma-Proteobacteria, Firmicutes,Actinobacteria and Bacteroidetes. Gammaproteobacteria was predominant in the two 16S rDNA clone libraries. Thirty-two endophytic bacteria were isolated and characterized with respect to heavy metal resistance and production of plant growth-promoting factors. In experiments involving rape plants grown in vermiculite containing 4 mg kg(-1) of Cu, inoculation with the isolates was found to increase the dry weights of roots (ranging from 132% to 155%) and above-ground tissues (ranging from 71% to 83%) compared to the uninoculated control. Increase in above-ground tissue Cu content varied from 63% to 125% in inoculated-rape plants cultivated in Cu-contaminated substrate compared to the uninoculated control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Bacteria / classification
  • Bacteria / drug effects*
  • Bacteria / genetics
  • Bacteria / isolation & purification
  • Base Sequence
  • Biodiversity*
  • Copper / pharmacology*
  • DNA Primers
  • DNA, Ribosomal / genetics
  • Metals, Heavy / toxicity*
  • Mining*
  • Phylogeny
  • Plants / microbiology*
  • Polymerase Chain Reaction
  • RNA, Ribosomal, 16S / genetics

Substances

  • DNA Primers
  • DNA, Ribosomal
  • Metals, Heavy
  • RNA, Ribosomal, 16S
  • Copper