Influence of Cadmium-Tolerant and Plant Growth-Promoting Rhizobacteria on Cadmium Accumulation and Growth Response of Wheat Seedlings Under Mountain Ecosystem

In the present study, cadmium tolerance potential of cold-tolerant and plant growth-promoting rhizobacteria (PGPR), namely Pseudomonas putida and Bacillus subtilis, and their effects on growth and Cd accumulation in wheat seedlings under mountain ecosystem have been studied. In petri-dish-based assays, P. putida and B. subtilis exhibited tolerance to Cd up to 18 mg l(-1) and 20 mg l(-1), respectively. In pot-based experiments, the bacterial inoculations that were carried out in two wheat cultivars (HPW-184 and HPW-236) under influence of Cd exposure (two doses @ 10 and 20 mg kg(-1) soil) resulted in improved seed germination, plant-growth-related parameters including root-shoot length and root-shoot biomass accumulation and allocation, results being statistically significant (p < 0.05) in most instances. Overall, the bacterial inoculations were useful in reducing the Cd stress in the wheat cultivars through reducing Cd accumulation in roots and shoots. Cd accumulation in roots and shoots was found in the order: control > P. putida > B. subtilis. The capacity of tested PGPR, B. subtilis and P. putida, originally isolated from Indian Himalayan Region, to protect the wheat plants through reducing Cd accumulation, and consequent inhibitory effects may be utilized in preventing Cd accumulation in the food chain and in improving growth of wheat crop under mountain ecosystem.