Nickel Solubilizing Capacity and Characterization of Rhizobacteria Isolated from Hyperaccumulating and Non-Hyperaccumulating Subspecies of Alyssum Serpyllifolium

• Published in: International journal of phytoremediation Vol. 13; no. 1; pp. 229 - 244
• Main Authors: Becerra-Castro, C, Prieto-Fernández, A, Álvarez-Lopez, V, Monterroso, C, Cabello-Conejo, M. I, Acea, M. J, Kidd, P. S
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis Group 2011; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Alyssum; Alyssum serpyllifolium; Biodegradation, Environmental; Biosurfactants; Brassicaceae - metabolism; Brassicaceae - microbiology; culture media; DNA; DNA fingerprinting; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; filtrates; genes; Genetic fingerprinting; Genotype; hyperaccumulators; indole acetic acid; Indoleacetic acid; Indoleacetic Acids; Metabolites; Nickel; Nickel - metabolism; Nucleotide sequence; Organic acids; Phylogeny; phytoextraction; Phytoremediation; Plant growth; Plant Leaves - metabolism; Plant Leaves - microbiology; Plant Roots - metabolism; Plant Roots - microbiology; Polymerase chain reaction; rhizobacteria; Rhizobiaceae - classification; Rhizobiaceae - isolation & purification; Rhizobiaceae - metabolism; Rhizosphere; rhizosphere bacteria; ribosomal RNA; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sequence analysis; serpentine; Serpentine soils; Soil; Soil microorganisms; Soil Pollutants - metabolism; Soils; Solubilization; Strains (organisms)
• ISSN: 1549-7879; 1522-6514; 1549-7879
• DOI: 10.1080/15226514.2011.568545

Bacterial strains were isolated from the rhizosphere of three populations of the Ni-hyperaccumulator Alyssum serpyllifolium subsp. lusitanicum (A. pintodasilvae; M, S, and L), one population of Ni-hyperaccumulator A. serpyllifolium subsp. malacitanum (A. malacitanum; SB), and one population of the non-hyperaccumulator A. serpyllifolium subsp. serpyllifolium (A. serpyllifolium; SN). Isolates were characterized genotypically by BOX-PCR genomic DNA fingerprinting and comparative sequence analysis of partial 16S rRNA gene, and phenotypically by their Ni tolerance (0–10 mM), presence of plant growth promoting traits (indoleacetic acid (IAA)-, siderophore-, or organic acid-production, and phosphate solubilization) or capacity to produce biosurfactants. Among the collection of rhizobacteria, 84 strains were selected (according to their BOX-PCR profiles and phenotypic characteristics) to assess their ability to modify Ni extractability from Ni-rich (serpentine) soils. Metabolites produced by 13 of the isolates mobilized soil Ni (originating from the rhizosphere of both Ni-hyperaccumulators and non-hyperaccumulator). In contrast, Ni extraction using culture medium filtrates which had supported the growth of 29 strains was significantly reduced. The remaining strains had no effect on Ni mobility. Bacterial induced Ni mobilization was not related to Ni resistance or the phenotypic traits tested. Isolates with potential use in phytoremediation techniques will be further studied in a plant-microorganism-soil system.