Isolation of cadmium-resistance and siderophore-producing endophytic bacteria and their potential use for soil cadmium remediation

Endophyte-assisted phytoremediation is an emerging technique for soil heavy metals (HMs) remediation and has become a research focus in the world because of benefits endophytes on plant growth uptake HMs. In this study, multifunctional endophytic bacteria strains were isolated screened, feasibility these cadmium (Cd) was investigated by incubation experiments pot experiments. All from roots woody plants grown Cd-contaminated soil. Seven had capacities to tolerate Cd toxicity produce siderophores, sequence analysis 16S rRNA gene classified as belonging genera Burkholderia, Pseudomonas, Pantoea, Herbaspirillum. able hydroxamate siderophores (32.40%–91.49%) three or more promoting properties such phosphorus solubilization, nitrogen fixation, indole acetic acid 1-aminocyclopropane-1-carboxylate deaminase production. They all strongly resistant Cd2+ toxicity, with minimum inhibitory concentration LB medium ranging 1.5 mM 9.0 mM. Except strain Burkholderia contaminans JLS17, other showed decreasing removal rates within continuously elevated 10–100 mg L−1. Compared uninoculated treatment, inoculation B.contaminans Pseudomonas lurida JLS32, Pantoea endophytica JLS50 effectively increased acid-soluble decreased reducible, oxidizable, residual soils different contamination levels. experiments, JLS17 YTG72 significantly (p < 0.05) promoted above-ground parts root system slash pine (Pinus elliottii) under stress. This study provides valuable biological resource endophyte-assisted theoretical basis application