Figure 7. Schematic presentation of HvAACT1 roles in barley.

HvAACT1 in the pericycle cells of root mature zone releases citrate to the xylem, which is required for the translocation of Fe from the roots to the shoots in both Al-sensitive and -tolerant cultivars. A 1-kb insertion in the upstream in the Al-tolerant cultivars alters the expression to the root tips and enhances the expression in both the root tips and mature zones. HvAACT1 expressed in the root tips releases citrate to the rhizosphere to detoxify Al.