Tolerance of Heavy Metal Toxicity Using PGPR Strains of Pseudomonas Species

Abstract Currently, rapid industrialization, overuses of chemical pesticides in the agriculture and other anthropogenic activities directly or indirectly lead to heavy metals contamination. Normal physiological functioning of plants and humans require metals, but their excessive accumulations have severe toxic effects on ecosystem and ecology of plants, and human. Therefore, there is an urgent need for the mitigation of heavy metals through eco-friendly means. Applications of plant growth promoting bacteria (PGPB) have appeared as a promising approach in the mitigation process of heavy metal tolerance. Pseudomonas is one of the most diversified bacterial genera broadly used as biocontrol, plant growth promoting agents as well as in the mitigation process of xenobiotics and heavy metals. Heavy metal tolerance involves some of the standard mechanisms like the transformation of metals into bioavailable and soluble form, bioaccumulation, production of extracellular polymeric substances (EPSs), siderophores production, etc. Also, Pseudomonas sp. possess plant growth promotion activity, such as synthesis of phytohormones, phosphorus solubilization, production of ammonia, HCN, and siderophore. Present review focused on the impact of heavy metals on the plant growth, and vis a vis the role of Pseudomonas sp. in the mitigation of heavy metal toxicity.