Nitric oxide and plant iron homeostasis.

AGUSTINA BUET; MARCELA SIMONTACCHI

Ferrara

Congreso; Third International Conference on Cellular Environmental Stressors in Biology and Medicine: Focus on Redox Reactions; 2014

Università di Ferrara

Nitric oxide and plant iron homeostasis   Agustina Buet and Marcela Simontacchi   Instituto de Fisiología Vegetal (INFIVE), UNLP-CONICET, La Plata, Buenos Aires, Argentina   Changes in iron homeostasis profoundly affects plant performance, crop yield and iron content in grains, which has direct consequences in human nutrition. Nitric oxide (NO) is involved as a signal in several growth and developmental processes, as well as in plant responses to environmental stress. NO acts as a central player in maintaining iron homeostasis by modifying Fe in terms of uptake from soil solution, transport, storage, and interaction with cellular components. Early observations that linked NO with the reverse of iron-deficiency induced chlorosis, led  to an investigation for the presence of nitrosyl-Fe complexes in embryonic axes exposed to exogenous NO (SNP, DETA-NONOate and GSNO). Both mono- and dinitrosyl-iron complexes were detected.  The formation of these complexes was dependent on iron and NO availability. Interestingly, the transit or labile iron pool, evaluated as the fraction chelated by deferoxamine, increased as a consequence of NO exposure. In addition, wheat plants suffering from common mineral nutrient deficiency were analyzed in relation to their iron content after exposure to exogenous NO. These results led to the conclusion that NO might revert symptoms of iron deficiency by increasing the availability of endogenous iron or facilitating iron delivery through the formation of mononitrosyl and dinitrosyl iron complexes. Moreover, NO is probably implicated in the general response against nutrient deficiency in plants.