ARA8 — Oryza sativa Japonica

Summary

OsARA8 (also known as CAD1, PCS1, PCS2) on rice chromosome 6 encodes a phytochelatin synthase, an enzyme with glutathione gamma-glutamylcysteinyltransferase activity (EC 2.3.2.15) that also binds cadmium, copper and other metals. The gene is associated with detoxification of arsenic and cadmium ions, phytochelatin biosynthesis, arsenite transport, copper detoxification, and glutathione metabolism. It has been linked to stress tolerance, particularly to cadmium and arsenite, as well as to immune signaling, callose deposition, and defense responses. Associations with plant organ development, chlorophyll metabolism, hormone biosynthesis, and jasmonic acid signaling have also been noted. The gene product localises to the plastid, cytosol and nucleus. Studies of related genes in other species link the family to heavy metal tolerance, phytochelatin synthesis, pathogen resistance, and seed germination.