Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water, and air. In order to select the plant growth-promoting rhizobacteria （PGPR） for ...Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water, and air. In order to select the plant growth-promoting rhizobacteria （PGPR） for phytoremediation of heavy metal contamination, 60 bacterial strains were isolated from the rhizosphere of two endemic plants, Prosopis laevigata and Spharealcea angustifolia, in a heavy metal-contaminated zone in Mexico. These rhizobacterial strains were characterized for the growth at different pH and salinity, extracellular enzyme production, solubilization of phosphate, heavy metal resistance, and plant growth-promoting （PGP） traits, including production of siderophores and indol-3-acetic acid （IAA）. Overall, the obtained rhizobacteria presented multiple PGP traits. These rhizoba^teria were also resistant to high levels of heavy metals （including As as a metalloid） （up to 480 mmol L-1 As（V）, 24 mmol L-1 Pb（II）, 21 mmol L-1 Cu（II）, and 4.5 mmol L-1 Zn（II））. Seven rhizobacterial strains with the best PGP traits were identified as members of Alcaligenes, Bacillus, Curtobacterium, and Microbacterium, and were selected for further bioassay. The inoculation of Brassica nigra seeds with Microbacteriurn sp. CE3R2, Microbacterium sp. NE1R5, Curtobacterium sp. NM1R1, and Microbacterium sp. NM3E9 facilitated the root development; they significantly improved the B. nigra seed germination and root growth in the presence of heavy metals such as 2.2 mmol L-1 Zn（II）. The rhizobacterial strains isolated in the present study had the potential to be used as efficient bioinoculants in phytorremediation of soils contaminated with multiple heavy metals.展开更多
基金supported by the Secretaría de Investigación y Posgrado-Insituto Politécnico Nacional (IPN), México (No. 20130722)the fellowships provided by Consejo Nacional de Ciencia y Tecnología (CONACYT), México+1 种基金by Becas de Estímulo Institucional de Formación de Investigadores-IPN, Méxicothe scholarships of Comisión de Operación y Fomentode Actividades Académicas and Estímulos al Desempeo de los Investigadores-IPN and Sistema Nacional de Investigadores-CONACYT, México
文摘Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water, and air. In order to select the plant growth-promoting rhizobacteria （PGPR） for phytoremediation of heavy metal contamination, 60 bacterial strains were isolated from the rhizosphere of two endemic plants, Prosopis laevigata and Spharealcea angustifolia, in a heavy metal-contaminated zone in Mexico. These rhizobacterial strains were characterized for the growth at different pH and salinity, extracellular enzyme production, solubilization of phosphate, heavy metal resistance, and plant growth-promoting （PGP） traits, including production of siderophores and indol-3-acetic acid （IAA）. Overall, the obtained rhizobacteria presented multiple PGP traits. These rhizoba^teria were also resistant to high levels of heavy metals （including As as a metalloid） （up to 480 mmol L-1 As（V）, 24 mmol L-1 Pb（II）, 21 mmol L-1 Cu（II）, and 4.5 mmol L-1 Zn（II））. Seven rhizobacterial strains with the best PGP traits were identified as members of Alcaligenes, Bacillus, Curtobacterium, and Microbacterium, and were selected for further bioassay. The inoculation of Brassica nigra seeds with Microbacteriurn sp. CE3R2, Microbacterium sp. NE1R5, Curtobacterium sp. NM1R1, and Microbacterium sp. NM3E9 facilitated the root development; they significantly improved the B. nigra seed germination and root growth in the presence of heavy metals such as 2.2 mmol L-1 Zn（II）. The rhizobacterial strains isolated in the present study had the potential to be used as efficient bioinoculants in phytorremediation of soils contaminated with multiple heavy metals.
