Isolation of As-tolerant bacteria and their potentials of reducing As and Cd accumulation of edible tissues of vegetables in metal(loid)-contaminated soils

• Published in: The Science of the total environment Vol. 579; pp. 179 - 189
• Main Authors: Wang, Xiaohan, Nie, Zongwei, He, Linyan, Wang, Qi, Sheng, Xiafang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-02-2017
• Subjects: Bioavailability; Brassica; Edible tissue As and Cd uptake; Exiguobacterium; Metal(loid)-contaminated soils; Metal(loid)-tolerant and plant growth-promoting bacteria; Ralstonia eutropha; Rhizobium tropici; Vegetables; Metal(loid)-tolerant and plant growth-promoting bacteria; Edible tissue As and Cd uptake; Metal(loid)-contaminated soils; Vegetables; Bioavailability
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2016.10.239

In this study, three As-tolerant bacteria Ralstonia eutropha Q2-8, Rhizobium tropici Q2-13, and Exiguobacterium aurantiacum Q3-11 were isolated from the rhizosphere and bulk soils of Chinese cabbage. The strains were characterized for their production of indole-3-acetic acid (IAA) and siderophores, their effects on soil metal(loid) bioavailability and organic matter content, and their effects on the edible tissue growth and metal(loid) accumulation of Chinese cabbage and radish in the metal(loid)-contaminated soil. The strains produced IAA and siderophores and increased the edible tissue biomass (ranging from 74% to 124%) of the vegetables compared to the controls. Furthermore, strain Q2-8 reduced As contents (ranging from 22% to 50%), while strains Q2-13 and Q3-11 decreased Cd contents (ranging from 21% to 53%) of the edible tissues of the vegetables compared to the controls. Strains Q2-8, Q2-13, and Q3-11 decreased the DTPA-extractable Cd contents (ranging from 16% to 41%) and increased the organic matter contents of the rhizosphere soils compared to the controls. The results showed the effects of the strains on the increased edible tissue growth and reduced As and Cd uptake of the edible tissues and highlighted the possibility to develop a new bacterial-assisted technique for reduced metal(loid) uptake of vegetables in the metal(loid)-contaminated soils.
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•Metal(loid)-resistant bacterial strains Q2-8, Q2-13, and Q3-11 were obtained.•The three strains increased the edible tissue biomass of Chinese cabbage and radish.•The three strains decreased the edible tissue As or Cd content of the vegetables.•The three strains decreased the DTPA-extractable Cd of the rhizosphere soils.•Strains Q2-8 and Q3-11 increased the organic matter content of the rhizosphere soils.