Nitric oxide and dinitrosyl iron complexes: roles in plant iron sensing and metabolism

This chapter aims to review the role of nitric oxide (NO) and dinitrosyl iron complexes (DNICs) in plants. NO is a signaling and physiologically active molecule in plants. However, the molecular mechanism/s involved in transducing the NO signal between cells and tissues is/are still unknown. The formation of low-molecular weight DNICs from internal NO sources has been recently demonstrated in plants. In addition, S-nitrosoglutathione (GSNO) has been shown to be a biologically active compound in plants. Both DNICs and GSNO are candidates for NO storage and/or mobilization between plant tissues and cells. NO has been shown to have a role in plant iron nutrition; therefore, it is proposed that DNICs and GSND may have roles in NO-mediated improvement of iron nutrition in plants growing under iron deficient conditions. It is suggested that the formation of DNICs constitutes a key process in plant iron sensing and metabolism. An interconversion between DNICs and GSNO based on the iron and NO status of the plant cell might be the core of a metabolic process leading plant iron homeostasis.