Microbes-mediated alleviation of heavy metal stress in crops: Current research and future challenges

Heavy metals (HMs) pollute the environment on a global scale and have different harmful effect on ecosystem. Outstripping accumulation of diverse toxic HMs in soils has altered the diversity, structure and function of microflora, degraded soils, reduces growth and yield of plant, and entered the food chain. HM treatment is necessary for maintaining the agricultural soil health. Many procedures and approaches have been used to recover contaminated soils in recent time, however, most of them were too pricey not environmentally friendly, and negatively affected soil properties. Usage of microbes was found as cost affective and ecofriendly approach for bioremediation of HMs. Microbes increased sustainability in agriculture soil health, which is essential to uninterrupted plant growth or improvement in stress full condition through mechanism likes productions phytohormones, organic acids, biosurfactants, exopolymers, antioxidant enzymes; and solubilization of phosphorus. It is well known that plant growth-promoting microbes enhance crop productivity and plant resistance to HM stress. In this following review, deep insight have has provided on mechanism of alleviation of HM stress by microbes and enhancement of plant growth promotion.