Arsenic Uptake and Transportation in Plants

Abstract

The arsenic uptake and translocation systems in plants are dependent on As species. Uptake of inorganic arsenate [Asin(V)] is conducted via specified group of high-affinity phosphate (Pi) transporters belonging to the PHS family, called Pi transporter 1. Recently identified transcription factors involved in the regulation of Asin(V) intake in plants are also described in this chapter. The role of other proteins such as mitochondrial proteins localized to the inner mitochondrial membrane and responsible for dicarboxylate exchange between the mitochondrial matrix and the cytosol or Pi transporter traffic facilitator 1 located in the endoplasmic reticulum (ER) of A. thaliana is not omitted. Uptake of inorganic arsenite [Asin(III)], as well as the organic derivatives of As from environment and distribution in plants, is conducted by channels created by proteins belonging to three of the five plant aquaporin subfamilies called nodulin 26-like intrinsic protein (NIP), membrane (PIP), and tonoplast intrinsic proteins (TIP). The significance of ABC (ATP-binding cassette) transporters which are responsible for transferring of Asin(III)-phytochelatin complexes across the tonoplast to the vacuole as well as the role of transporters responsible for inositol uptake in As translocation from the xylem into the phloem is explained. Additionally, the meaning of some elements like S, Si, and Fe in As influx in plants is considered.