Interaction of Cd-hyperaccumulator Solanum nigrum L. and functional endophyte Pseudomonas sp. Lk9 on soil heavy metals uptake

• Published in: Soil biology & biochemistry Vol. 68; pp. 300 - 308
• Main Authors: Chen, Liang, Luo, Shenglian, Li, Xiaojie, Wan, Yong, Chen, Jueliang, Liu, Chengbin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.01.2014; Elsevier
• Subjects: acid phosphatase; aerial parts; Agronomy. Soil science and plant productions; bioaccumulation factor; Bioaugmentation; Biochemistry and biology; Biological and medical sciences; biosurfactants; cadmium; Chemical, physicochemical, biochemical and biological properties; copper; endophytes; Functional endophyte; Fundamental and applied biological sciences. Psychology; Heavy metal; heavy metals; inoculum; iron; microbial biomass; nutrition; organic acids and salts; Parasitic plants. Weeds; phosphorus; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Phytoextraction; Phytopathology. Animal pests. Plant and forest protection; phytoremediation; polluted soils; Pseudomonas; Pseudomonas sp. Lk9; secretion; siderophores; Soil and water pollution; soil microorganisms; Soil science; Solanum nigrum; Weeds; zinc; Solanum nigrum; Bioaugmentation; Functional endophyte; Phytoextraction; Pseudomonas sp. Lk9; Heavy metal; Pseudomonadales; Weed; Pseudomonas; Soils; Absorption; Dicotyledones; Angiospermae; Hyperaccumulator; Bacteria; Pseudomonadaceae; Endophyte; Spermatophyta; Soil science; Solanaceae
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2013.10.021

Bioaugmentation is a promising method for assisting phytoextraction of heavy metals from contaminated soil, and the development of bioaugmentation-assisted phytoextraction requires the understanding of the mechanism involved in the interaction between plants and inocula. In this study, a pot study was conducted to evaluate the effect of bacterial endophyte Pseudomonas sp. Lk9 which can produce biosurfactants, siderophores and organic acids on the growth and metal uptake of Cd-hyperaccumulator Solanum nigrum L. growing in multi-metal-contaminated soil. The results revealed that Lk9 inoculation could improve soil Fe and P mineral nutrition supplies, enhance soil heavy metal availability, and affect host-mediated low-molecular-weight organic acids secretion, thereby significantly increasing S. nigrum shoot dry biomass by 14% and the total of Cd by 46.6%, Zn by 16.4% and Cu by 16.0% accumulated in aerial parts, compared to those of non-inoculated control. The assessment of phytoextraction showed that Lk9 inoculation elevated the bioaccumulation factor of Cd (28.9%) and phytoextraction rates of all metals (17.4%, 48.6% and 104.6% for Cd, Zn and Cu, respectively), while the translocation factors had negligible difference between Lk9 inoculation (3.30, 0.50 and 0.40 for Cd, Zn and Cu, respectively) and non-inoculated control (2.95, 0.53 and 0.42 for Cd, Zn and Cu, respectively). It was also found that the symbiotic association between S. nigrum and Lk9 significantly increased the soil microbial biomass C by 39.2% and acid phosphatase activity by 28.6% compared to those in S. nigrum without Lk9. This study would provide a new insight into the bioaugmentation-assisted phytoextraction of heavy metal-contaminated soils. [Display omitted] •Functional Pseudomonas sp. Lk9 enhanced Solanum nigrum extraction of Cd, Zn and Cu.•Lk9 inoculation improved soil Fe, P mineral nutrition supplies.•Lk9 inoculation enhanced soil Cd, Zn and Cu bioavailability.•Lk9 inoculation affected host-mediated low-molecular-weight organic acids secretion.•Lk9 is a good candidate for bioaugmentation-assisted metal phytoextraction.