The potential of cadmium ion-immobilized Rhizobium pusense KG2 to prevent soybean root from absorbing cadmium in cadmium-contaminated soil

• DOI: 10.1111/jam.14165
• Publication Date: 2018-11-29T14:33:39Z
• Authors: Y. Li; X. Yu; Y. Cui; W. Tu; T. Shen; M. Yan; Y. Wei; X. Chen; Q. Wang; Q. Chen; Y. Gu; K. Zhao; Q. Xiang; L. Zou; M. Ma
• Keywords: 0301 basic medicine; 2. Zero hunger; 03 medical and health sciences; Glycine max; Soil Pollutants; Agriculture; Food Contamination; Cells, Immobilized; Plant Roots; 6. Clean water; Cadmium; Rhizobium

Because the effect of Cd2+ -immobilized microbe on Cd uptake of plants in Cd-contaminated soil remains underexplored, this study focuses on the effect of Cd2+ -immobilized rhizobia on Cd uptake of soybean.Strain KG2 from soybean nodule was identified as Rhizobium pusense KG2 by phylogenetic analysis. Rhizobium pusense KG2 showed the 120 mg l-1 of minimal lethal concentration for Cd2+ . In 50 and 100 mg l-1 of Cd2+ liquid, approximately 2 × 1010 cells removed 56·71 and 22·11% of Cd2+ , respectively. In pot soil containing 50 and 100 mg kg-1 of Cd2+ , strain KG2 caused a 45·9 and 35·3% decrease in soybean root Cd content, respectively. Meanwhile, KG2 improved the root and shoot length, nitrogen content and biomass of soybean plants and superoxide dismutase activity.The Cd2+ -immobilized rhizobia could inhibit soybean plants to absorb Cd2+ from soil, promote plant growth and improve plant's tolerance against Cd. This study is the first time to report that R. pusense is an effective nodulating rhizobium of legume.Some Cd2+ -immobilized microbe lowering Cd uptake of plant and promoting plant growth should be considered as an effective strategy for producing safety crops in the Cd-contaminated agricultural soil.