Insight into the mechanisms of plant growth promoting strain SNB6 on enhancing the phytoextraction in cadmium contaminated soil

• Published in: Journal of hazardous materials 2020-03, Vol.385, p.121587, Article 121587
• Main Authors: Wu, Bin, He, Tingting, Wang, Ziru, Qiao, Suyu, Wang, Ying, Xu, Fei, Xu, Heng
• Format: Article
• Language: English
• Subjects: Biodegradation, Environmental; Biological Availability; Biomass; Cadmium; Cadmium - isolation & purification; Cadmium - pharmacokinetics; Cadmium - toxicity; Chrysopogon - drug effects; Chrysopogon - growth & development; Chrysopogon - metabolism; Chrysopogon - microbiology; Phytoextraction; Plant growth-promoting rhizobacteria; Rhizosphere; Soil Pollutants - isolation & purification; Soil Pollutants - pharmacokinetics; Soil Pollutants - toxicity; Vetiver grass; Whole genome
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.121587

[Display omitted] •The mechanisms of SNB6 assisted vetiver grass on Cd phytoextraction were studied.•The genes of Cd tolerance and plant growth promotion in SNB6 were revealed.•SNB6 increased Cd bioavailability and stimulated soil biochemical properties.•SNB6 enhanced the antioxidative enzyme activities of vetiver grass.•SNB6 significantly increased the biomass and Cd content of plant. Plant growth-promoting rhizobacteria (PGPR) assisted accumulator has been proposed as a phytoextraction method to clean cadmium (Cd) in contaminated soil, while the mechanisms were few studied regrading PGPR-soil-accumulator as an assemble. In this study, we revealed the possible mechanisms of the plant growth-promotion strain SNB6 on enhancing the Cd phytoextration of vetiver grass by the analysis of the whole genome of SNB6, soil biochemical properties and plant growth response. Results showed that SNB6 encoded numerous genes needed for Cd tolerance, Cd mobilization and plant growth promotion. SNB6 increased HOAc-extractable Cd that showed a positive correlation with Cd uptake in accumulator. In addition, SNB6 improved the biochemical activities (bioavailability of nutritional substances, bacterial count, soil respiration and enzyme activity) in rhizosphere soil. Moreover, the antioxidative enzymes activities of accumulator were significantly enhanced by SNB6. Consequently, SNB6 promoted Cd uptake and biomass of accumulator, thus enhancing the Cd phytoextraction. The maximum Cd extractions in root, stem and leaf reached to 289.47 mg/kg, 88.33 mg/kg and 59.38 mg/kg, respectively. Meanwhile, the total biomass of accumulator was increased by 9.68–45.99% in SNB6 treatment. These findings could be conducive to the understanding the mechanisms of PGPR on enhancing the Cd phytoextraction of accumulator.