In vitro, possesses glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene (CDNB) and glutathione peroxidase activity toward cumene hydroperoxide and linoleic acid-13-hydroperoxide. May be involved in the conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles and have a detoxification role against certain herbicides. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) Isoform 1 is predominantly expressed in leaves and isoform 2 in roots. By salicylic acid, ethylene, methyl jasmonate, auxin, H(2)O(2), metolachlor, and the pathogen Hyaloperonospora parasitica. Belongs to the GST superfamily. Phi family.