Thioredoxin h System and Wheat Seed Quality

Thioredoxin is one of the key systems controlling cellular redox balance in all living organisms. Plant thioredoxins are a diverse multigene family divided into two systems, the chloroplastic and the cytoplasmic systems, which are distinguishable by the electron donor and by the enzyme that catalyses thioredoxin reduction. In cereal seed, the thioredoxin (Trx) h system acts in the developing phase. controlling the delivery of compounds during seed filling. Early in the development of the imbibed seed. it promotes the mobilization of storage nitro.-en and carbon in the endosperm by inhibiting the inactivators of amylolytic enzyme and by activating a specific serine protease, thiocalsin. During seed maturation and germination, the Trx It system controls oxidative stress ill the livin,, tissues. specifically in the scutellum and the aleurone layer, where it accumulates ill the nucleus. The overexpression and the suppression of Trx confirm these features and constitute a powerful tool to manage seed quality. due to the large number of Trx h isoforms and to the specific nature of some of them.