Mitigation of cadmium phytotoxicity and enhancement of selected nutritional and active components in Artemisia selengensis turcz through co-inoculation with plant growth-promoting and cadmium-tolerant rhizobacteria.

Abstract

Cadmium (Cd) accumulation in plants poses a serious risk to crop growth and human health. Although rhizobacteria are known to enhance plant Cd tolerance, research on rhizobacterial consortium to alleviate Cd toxicity in crops under hydroponic conditions remains limited. Two rhizobacterial strains, Bacillus cereus TLMC1 and Pseudomonas putida TLMC5, exhibiting high Cd tolerance and strong plant growth-promoting (PGP) traits, were selected to investigate their synergistic effects on Artemisia selengensis Turcz under Cd stress. Single and co-inoculation significantly decreased shoot Cd content and increased root Cd content, with co-inoculation yielding the lowest Cd translocation factors (0.08 and 0.09 under 1 and 10 mg L-1 Cd stress, respectively). Co-inoculation maximally reduced SOD and POD activities by 27.52% and 20.34% under 1 mg L-1 Cd stress. Soluble sugars, soluble proteins, vitamin C, and total flavonoids in edible shoots were all elevated, with co-inoculation showing optimal performance. Despite the reduction of Target Hazard Quotient (THQ) after inoculation, the minimum value remained above the safety threshold. These findings demonstrated that TLMC1 and TLMC5 co-inoculation effectively reduced Cd uptake and enriched nutritional and active components in the edible parts of A. selengensis, offering a preliminary microbial strategy for Cd risk mitigation in moderately Cd-polluted regions.