Phytochelatins: Heavy Metal Detoxifiers in Plants

Abstract

Heavy metals including cobalt, copper, manganese, molybdenum, and zinc are required by plants and other living organisms in trace levels for growth. Heavy metals, on the other hand, can be harmful in large doses. Plants, like other species, have a variety of detoxification processes to combat heavy metal toxicity. Heavy metal chelation by phytochelatins and metallothioneins, binding with plant cell walls and root excretions, metal efflux from the plasma membrane, metal chelation by phytochelatins and metallothioneins, and compartmentalization inside the vacuole are all examples. Plants have tiny metal-binding peptides called phytochelatins (PCs). PCs, metallothioneins, organic acids, and amino acids are the most common metal chelators. PCs are found in many higher plants, fungi such as Schizosaccharomyces pombe, Candida glabrata, and Mucroracemosus, algae, bryophytes, pteridophytes, and gymnosperms, and algae, bryophytes, pteridophytes, and gymnosperms. The inactive toxic metal ions of metal—PC chelatins were then transported from the cytosol to the vacuole before poisoning the enzymes of life-sustaining metabolic pathways, and transiently stored in the vacuole to reduce the heavy metal concentration in the cytosol, allowing for heavy metal detoxification. PC production in response to heavy metal stress is one of the truly adaptive responses that occur frequently in higher plants. The buildup of PC in heavy metal tolerant genotypes is substantially higher than in non-tolerant lines. The substrate for the synthesis of PC, which chelated the metals, is glutathione (GSH).