Abstract

Aims Metal contamination poses a global threat due to its widespread occurrence and the high toxicity of these elements. Phytoremediation has emerged as a preferred approach for the bioremediation of metal-contaminated soils. The search for microorganisms facilitating phytoremediation, especially plant-growth-promoting bacteria (PGPB), has become critical to advance ecosystem remediation efforts. This research aimed to characterize in-depth a Priestia megaterium strain isolated from multimetal contaminated soils located at the Atacama Desert, showing potential for bacteria-assisted phytoremediation . Methods and Results The strain MOD5IV exhibited notable PGPB features: phosphate and potassium solubilization, nitrogen fixation, phytohormone production, and growth promotion of Arabidopsis thaliana. Genomic analysis revealed a 5,254,635 bp chromosome plus nine plasmids, hosting over 6,000 genes. Functional annotation identified genes associated with resistance to copper, cadmium, lead, mercury, zinc, and cobalt. Also, genes linked to PGPB capabilities as siderophore-production, nutrient-solubilization, IAA-synthesis, and nitrogen-fixation. Accordingly, MOD5IV exhibited robust tolerance to multiple metals and enhanced the phytoremediation potential of Caesalpinia Spinosa (Mol.) in laboratory trials. Conclusions MOD5IV proved to have promising traits for microbe-assisted phytoremediation of metal-contaminated soils. Impact Statement This study contributed to the characterization of new native multi-metal-resistant PGPR bacteria for phytoremediation of metal-contaminated soils. Increasing the evidence of the Atacama Desert as a source of microbiological solutions for climate adaptation and environmental remediation.