Rhizobacteria-<i>Pseudomonas guguanensis</i> SMHMZ4 Isolated from Mines Area Assists Green-Remediation of Cadmium by <i>Brassica juncea</i>: a Promising Environment Sustainable approach

Abstract

The aim of this study was to investigate how metal-tolerant rhizobacteria isolated from the mine area and landfill site influence the phytoremediation efficacy of B. juncea plants in metal-contaminated soils. Out of four cadmium-tolerant rhizobacteria, isolate SMHMZ4 showed the promising phytoextraction efficacy of B. juncea. Isolate SMHMZ4 was identified as Pseudomonas guguanensis and submitted to NCBI GenBank under accession number MZ145097. These rhizobia were reported for the first time to support metal-Cd phytoremediation using B. juncea. Compared with the non-inoculated control, SHMMZ4 treatment significantly improved the germination of B. juncea seeds and increased soluble heavy metals in soil by 7.78 times. Growth and health parameters, pigment and metal accumulation in roots and shoots of isolate SHMMZ4 inoculated B. juncea grown in individual soil contaminated with 94.95 μg g-1 CdCl2 were significantly increased. Pot experiments showed that SHMMZ4 could transfer heavy metals from soil to roots, from roots to shoots and the values of translocation coefficient, bioconcentration coefficient, and bioaccumulation coefficient were 1.28, 1.22, and 1.72, respectively, which were significantly higher than the non-inoculated control. In the present study it is demonstrated that the amendments of rhizobacteria to B. juncea is believed to be a more promising method for green remediation of cadmium.