The interplay between reactive oxygen and nitrogen species contributes in the regulatory mechanism of the nitro-oxidative stress induced by cadmium in Arabidopsis

Abstract Nitric oxide ( NO) involved in various metabolic processes in plants. Although its significant influence has been established, the exact mechanisms of NO-derived products under metal-stress conditions are largely unknown. Here, we investigated the key components of reactive oxygen/nitrogen species (ROS/RNS) metabolisms under cadmium (Cd) stress using Arabidopsis as the model plant. Exposure to Cd disturbed redox homeostasis and increased lipid peroxidation, thus triggering oxidative stress. Complementarily, Cd caused differential changes in the selected amino acids: a promotion in partial amino acids might be a genotype-specific trait, while the phenylalanine ammonia-lyase activity increased in a dose-dependent manner in shoots. Furthermore, NO production as well as S -nitrosoglutathione (GSNO) reductase (GSNOR) activity were up-regulated by Cd with the simultaneous depletion of GSNO. Correspondingly, S -nitrosothiols were involved in generating peroxynitrite and tyrosine nitration of protein (NO 2 -Tyr), in accordance with the regulation of NO-mediated post-translational modifications in antioxidant systems, including the ascorbate-glutathione cycle, amino acids and phenolic compounds, thereby provoking nitrosative stress. Our data provide comprehensive evidences regarding the clear relationships between the metabolisms of ROS and RNS, supporting the indicator role of NO 2 -Tyr as a nitrosative stress in plants, and help to provide a better understanding of the ROS/RNS interaction under stress conditions.