title: IAA production by Bacillus sp. JH 2-2 promotes Indian mustard growth in the presence of hexavalent chromium.
abstract: Bacillus sp. strain JH 2-2, isolated from the rhizosphere of plants at a multi-metal contaminated mine site, has the potential to reduce Cr(VI) to Cr(III) and promote plant growth by reducing Cr toxicity and producing IAA. The minimum inhibitory concentration of Cr(VI) to Bacillus sp. JH 2-2 was 1000 mg L(-1) and the strain reduced 99% of 10 mg Cr(VI) L(-1) to Cr(IV) within 24 h. Lower Cr(VI) stress (10 mg L(-1) ) stimulated IAA production, but much less IAA was produced at 30 or 50 mg Cr(VI) L(-1) . Inoculation with Bacillus sp. JH 2-2 increased the length of Brassica juncea L. roots by 364% and stems by 735% in the presence of 10 mg Cr(VI) L(-1) from those of uninoculated control plants. These findings suggest potential use of Bacillus sp. JH 2-2 to promote phytoremediation of soil contaminated with Cr(VI).
authors.affiliation: Division of Biotechnology, Advanced Institute of Environment and Bioscience, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, South Korea; School of Natural Resources, University of Nebraska-Lincoln, Lincoln, USA.
authors.forename: Jaehong
authors.initials: J
authors.lastname: Shim
authors.forename: Jin-Won
authors.initials: JW
authors.lastname: Kim
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Shea
authors.forename: Byung-Taek
authors.initials: BT
authors.lastname: Oh
mesh_terms: D001407:Bacillus / Q000187:drug effects / Q000378:metabolism*; D001711:Biotransformation; D002857:Chromium / Q000378:metabolism* / Q000633:toxicity; D007210:Indoleacetic Acids / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D009149:Mustard Plant / Q000254:growth & development* / Q000382:microbiology*; D010084:Oxidation-Reduction; D063245:Plant Development; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development; D018547:Plant Stems / Q000254:growth & development; D012989:Soil Pollutants / Q000378:metabolism* / Q000633:toxicity
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D012989:Soil Pollutants; D002857:Chromium; C074702:chromium hexavalent ion; C030737:indoleacetic acid
keywords: Bacillus sp.; Hexavalent chromium; Hormesis; IAA (Indole-3-acetic acid); Phytoremediation