16 - Microbial symbionts for alleviation of heavy metal toxicity in crop plants

Abstract

Due to various anthropogenic activities, crop plants are witnessing the havoc of heavy metal toxicity. From various sources, the heavy metals get accumulated in the soil and are taken up by the plants if they are grown in heavy metal-contaminated soil. Due to the accumulation of heavy metals, the metabolism of the plants gets affected which leads to yield penalty. Biostimulants are recently emerging as an effective means for alleviating heavy metal toxicity in crop plants. There are two main categories of biostimulants namely, nonmicrobial biostimulants and microbial biostimulants. The microbial biostimulants help in remediating heavy metal stress from crop plants by activating various physiological and biochemical mechanisms. Microbial biostimulants have several advantages over nonmicrobial biostimulants due to their eco-friendly nature and they are endowed with several plant growth-promoting traits. Further, the formulation of microbial biostimulants with other beneficial microbes or inorganic and organic chemicals is found to be a more effective means for alleviating plant stress including heavy metal stress.