Specific redox regulation of carbohydrate, organic acid, amino acid and polyamine levels in maize seedlings

• Redox compounds (Asc, H 2 O 2 , NaHS) modulate NO, sugars, and TCA metabolites in maize. • Amino acid profiles shift distinctly: Asc lowers Glu-family and H 2 O 2 boosts Ser/Gly • Polyamine metabolism is redox-sensitive, with PUT, SPD, and SPM showing treatment-specific changes. • Gene expression reprogramming links redox balance to nitrogen, amino acid, PA, and hormone metabolism. Despite the well-known importance of the redox system in the regulation of metabolism, further research is required to elucidate the specific role of its constituent components. In this study, we found that ascorbate (Asc), hydrogen peroxide (H 2 O 2 ) and hydrogen sulphide (H 2 S) have different effects on the diverse metabolites present in maize seedlings. Interestingly, Asc treatment led to an increase in nitric oxide (NO) levels even after three days, while the other two compounds exerted their effects only after 7 days. In parallel, Asc-treated seedlings had greater carbohydrates (arabinose, ribose) content after 3 days, and diminished levels of organic acids (malate, citrate), amino acids (Asp, Thr, Ser, Asn, Glu, Gly, Ala, Tyr, Orn), and polyamines (PUT, SPD and DAP) levels after 7 days compared to H 2 O 2 - and H 2 S-treated ones. Furthermore, the expression levels of several genes related to the metabolism of these compounds exhibited variations between the treatments. The observations presented here demonstrate coordinated, compound-specific redox control of citrate cycle, carbohydrate, amino acids, and polyamine metabolism. This regulation may be of significance in the acclimatisation to environmental changes or the enrichment of agronomically important compounds in crops.