Culturable heavy metal-resistant and plant growth promoting bacteria in V-Ti magnetite mine tailing soil from Panzhihua, China

PLoS One. 2014 Sep 4;9(9):e106618. doi: 10.1371/journal.pone.0106618. eCollection 2014.

Abstract

To provide a basis for using indigenous bacteria for bioremediation of heavy metal contaminated soil, the heavy metal resistance and plant growth-promoting activity of 136 isolates from V-Ti magnetite mine tailing soil were systematically analyzed. Among the 13 identified bacterial genera, the most abundant genus was Bacillus (79 isolates) out of which 32 represented B. subtilis and 14 B. pumilus, followed by Rhizobium sp. (29 isolates) and Ochrobactrum intermedium (13 isolates). Altogether 93 isolates tolerated the highest concentration (1000 mg kg(-1)) of at least one of the six tested heavy metals. Five strains were tolerant against all the tested heavy metals, 71 strains tolerated 1,000 mg kg(-1) cadmium whereas only one strain tolerated 1,000 mg kg(-1) cobalt. Altogether 67% of the bacteria produced indoleacetic acid (IAA), a plant growth-promoting phytohormone. The concentration of IAA produced by 53 isolates was higher than 20 µg ml(-1). In total 21% of the bacteria produced siderophore (5.50-167.67 µg ml(-1)) with two Bacillus sp. producing more than 100 µg ml(-1). Eighteen isolates produced both IAA and siderophore. The results suggested that the indigenous bacteria in the soil have beneficial characteristics for remediating the contaminated mine tailing soil.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus / metabolism
  • Bacillus / physiology
  • Bacteria / metabolism*
  • Metals, Heavy / metabolism*
  • Mining*
  • Ochrobactrum / metabolism
  • Ochrobactrum / physiology
  • Plant Development / physiology*
  • Rhizobium / metabolism
  • Rhizobium / physiology
  • Siderophores / metabolism
  • Soil Microbiology

Substances

  • Metals, Heavy
  • Siderophores

Grants and funding

This work was financially supported by National Natural Science Foundation of China (NO. 31300461), Doctoral Fund of Ministry of Education of China (NO. 20135103120003), and Research Foundation for the Introduction of Talent of Sichuan Agricultural University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.