Regulation of the Thioredoxin System by Quercetin and Kaempferol in Arsenic Stressed Wheat (Triticum aestivum L.)

Thioredoxins (TRXs) are small proteins that function as redox regulators in various metabolic processes. However, due to the complexity of the thioredoxin system, research on its role in stress tolerance remains limited. This study aimed to elucidate the mechanisms by which quercetin (Q) and kaempferol (K) influence the transcription levels of NTRA, TRX15, TRX4, and TRXh1 genes, which are associated with the chloroplastic and cytoplasmic thioredoxin systems in wheat seedlings under arsenic (As) stress. The expression of TRX system-related genes was found to be reduced in wheat leaves subjected to As stress. While the expression of NTRA and TRX15 genes showed a slight increase in the As+Q group, Q did not exhibit a dominant effect on the regulation of the thioredoxin system. Similarly, As+K treatment led to an increase in TRXh1 gene expression. Although the regulatory effect of K was only noticeable with the combined application of Stress+Q+K, this effect was not strong enough to suggest that the thioredoxin system plays an active role in the stress response.