A physiological perspective on targets of nitration in NO-based signaling networks in plants.

Although peroxynitrite (ONOO-) has been well documented as a nitrating cognate of nitric oxide (NO) in plant cells, modifications of proteins, fatty acids, and nucleotides by nitration are relatively under-explored topics in plant NO research. As a result, they are seen mainly as hallmarks of redox processes or as markers of nitro-oxidative stress under unfavorable conditions, similar to those observed in human and other animal systems. Protein tyrosine nitration is the best-known nitrative modification in the plant system and can be promoted by the action of both ONOO- and related NO-derived oxidants within the cell environment. Recent progress in 'omics' and modeling tools have provided novel biochemical insights into the physiological and pathophysiological fate of nitrated proteins. The nitration process can be specifically involved in various cell regulatory mechanisms that control redox signaling via nitrated cGMP or nitrated fatty acids. In addition, there is evidence to suggest that nitrative modifications of nucleotides embedded in DNA and RNA can be considered as smart switches of gene expression that fine-tune adaptive cellular responses to stress. This review highlights recent advances in our understanding of the potential implications of biotargets in the regulation of intracellular traffic and plant biological processes.