Genetic diversity and characterization of heavy metal-resistant-endophytic bacteria from two copper-tolerant plant species on copper mine wasteland.
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.
Sun
Le-Ni
LN
MOA Key Laboratory of Microbiological Engineering of Agricultural Environment, College of Life Science, Nanjing Agricultural University, Nanjing 210095, PR China.
Zhang
Yan-Feng
YF
He
Lin-Yan
LY
Chen
Zhao-Jin
ZJ
Wang
Qing-Ya
QY
Qian
Meng
M
Sheng
Xia-Fang
XF
D000222:Adaptation, Physiological; D001419:Bacteria / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D044822:Biodiversity; D003300:Copper / Q000494:pharmacology*; D017931:DNA Primers; D004275:DNA, Ribosomal / Q000235:genetics; D019216:Metals, Heavy / Q000633:toxicity*; D008906:Mining; D010802:Phylogeny; D010944:Plants / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D017931:DNA Primers; D004275:DNA, Ribosomal; D019216:Metals, Heavy; D012336:RNA, Ribosomal, 16S; D003300:Copper