The Role of ABC Transporters in Metal Transport in Plants

The metal ions are very essential for the survival, being an important part of many biological processes; however excess of metals causes toxicity. Correct balance of metal ions is necessary in the acquisition of metals depending on physiological needs. The uptake and transport of the essential metals occur with the help of metal transporters, which are also involved in homeostasis of metals. The metal transporters are found to be localized in different cellular compartments in different tissues depending upon their uptake in root cells and transport from root to xylem and to shoot and sequestration in vacuole to maintain the homeostasis. Different classes of transporters which are involved in uptake, transport, and sequestration of metals are discussed of which ATP binding cassette (ABC) family of transporters constitutes the largest family of transporters. Originally, ABC transporters in plants were identified in detoxification process where they exhibited important role in heavy metal detoxification and in metal homeostasis in cell. This chapter discusses the different subfamilies of ABC transporters and their role in metal transport and sequestration.