Effect of Novosphingobium sp. CuT1 inoculation on the rhizoremediation of heavy metal- and diesel-contaminated soil planted with tall fescue

Abstract

Rhizoremediation is a promising method based on the synergism between plant and rhizobacteria, which constitutes a promising means to remediate soil co-contaminated with heavy metals and total petroleum hydrocarbons (TPHs). A plant growth-promoting (PGP) rhizobacterium with diesel-degrading capacity and heavy metals tolerance was isolated from the rhizosphere of tall fescue (Festuca arundinacea L.), after which the effects of its inoculation on rhizoremediation performance were evaluated in heavy metal and diesel-contaminated soil planted with tall fescue.The bacterial isolate (Novosphingobium sp. CuT1) was characterized by its production of indole-3-acetic acid (IAA), 1-aminocyclopropane-1carboxylic acid (ACC) deaminase activity, and siderophore productivity as PGP traits. CuT1 was able to grow on 1/10 LB-agar plates containing 5 mM of Cu or 5 mM of Pb. Compared to the rhizoremediation performance of the co-contaminated soil (Cu + Pb + diesel) without inoculation, the bioavailable Cu concentrations in soil and the biomass of tall fescue were signi cantly increased CuT1 inoculation. Additionally, the root growth of tall fescue was also promoted CuT1 inoculation. Correlation analysis showed that Cu bioavailability and bioconcentration factor were positively correlated with CuT1 inoculation. The diesel removal e ciency showed a positive correlation with CuT1 inoculation although diesel removal was below 30%. CuT1 inoculation was positively correlated with IAA and dehydrogenase activity in soil. Moreover, the dry biomass of the tall fescue's roots was highly associated with CuT1 inoculation. Collectively, our ndings suggest that Novosphingobium sp. CuT1 can be utilized as an applicable bioresource to enhance rhizoremediation performance in heavy metal-and TPH-contaminated soils.

Remediation of Leachate-Metal-Contaminated Soil Using Selected Bacterial Consortia

“…This is probably due to the role played by the introduced microorganisms. This agrees with published findings that have highlighted the effectiveness of microbes in the bioremediation of metal-contaminated soils [60,61].…”

Using Isoform Sequencing for De Novo Transcriptome Sequencing and the Identification of Genes Related to Drought Tolerance and Agronomic Traits in Tall Fescue (Festuca arundinacea Schreb.)

“…is extensively planted in warm temperate to subtropical regions worldwide. Tall fescue is widely used for forage and turf and contributes to soil conservation and environmental protection because of its exceptional resistance to abiotic stress, particularly drought [1][2][3][4][5][6][7]. The mechanism underlying the adaptation of tall fescue to abiotic stress has attracted widespread interest; however, its understanding at the genetic level is rudimentary [5,7].…”

Isolation and Characterization of Plant Growth-Promoting Bacteria for the Phytoremediation of Diesel- and Heavy Metal-Contaminated Soil

“…Rhizobacteria were isolated from the rhizosphere of tall fescue (Festuca arundinacea) grown in soil co-contaminated with diesel and heavy metals for two years. The soil was artificially polluted with diesel, Cu, Pb, and Cd at final concentrations of 30,000 mg-total petroleum hydrocarbons (TPH)• kg-soil -1 , 500 mg-Cu• kg-soil -1 , 500 mg-Pb• kg-soil -1 , and 20 mg-Cd• kg-soil -1 , respectively [11]. The pH, water content, and organic matter content of the soil was 6.90 ± 0.06, 40.33 ± 1.40%, and 9.16 ± 1.25%, respectively.…”

“…Briefly, 0.3 ml of cell culture (OD 600 of 0.6) was cultured in 30 ml of nutrient broth (1%, v/v) at a specific temperature (25−40℃) for 1−6 days. Our previous study described the procedure in more detail [11]. The absorbance was measured using a UV/Vis spectrometer (Biochrom Ltd.) at 700 nm, and the quantity of siderophores produced was expressed as µM-benzoic acid (BA)•mg-DCW -1 .…”

“…They were identified by a 16S rRNA sequencing analysis. To obtain genomic DNA, a colony was vortexed with 30 µl of sterilized water for 30 s. The suspension was heat-treated in a heating block at 95℃ for 15 min and then centrifuged at 11,000 rpm for 30 s [11]. The procedure was repeated three times.…”