Probable thiol-disulfide oxidoreductase involved in resistance to oxidative stress. May participate in the reduction of alkyl hydroperoxides derived from oxidative stress by acting as a physiological electron donor to the BAS1 peroxiredoxin. May regenerate methionine sulfoxide reductase B1 (MSRB1) activity through sulfenic acid reduction. Interacts with the plastidial peroxiredoxin BAS1. By drought stress and photooxidative conditions. Belongs to the thioredoxin family.