Thiol-disulfide oxidoreductase involved in response to pathogens and oxidative stresses. Required for the response to victorin, a phytotoxin which induces programmed cell death in sensitive plants. Possesses insulin disulfide bonds reducing activity. Interacts with MDH1. By treatment with salicylic acid (SA), abscisic acid (ABA), iron, copper and UV-C. Induced by wounding, oxidative stress, infection with incompatible P.syringae and treatment with the fungal phytotoxin victorin. Insensitivity to victorin phytotoxin. Belongs to the thioredoxin family. Plant H-type subfamily. The active site contains a CPPC motif wich differs from the conserved CGPC motif.