Need of biomarkers of nitrosative stress in plants

Abstract

Reactive oxygen species (ROS) and oxidative stress are well recognized terms in plant physiology and biochemistry [ 1 Mittler R. Oxidative stress, antioxidants and stress tolerance. Trends Plant Sci. 2002; 7: 405-410 Abstract Full Text Full Text PDF PubMed Scopus (7476) Google Scholar ]. However, the same is not true for the terms reactive nitrogen species (RNS) and nitrosative stress, despite the fact that the gaseous radical nitric oxide ( NO) is one of the molecules that has attracted most attention from plant biologists in the last decade, owing to its physiological implications in plant signaling, growth and development [ 2 Lamattina L. et al. Nitric oxide: the versatility of an extensive signal molecule. Annu. Rev. Plant Biol. 2003; 54: 109-136 Crossref PubMed Scopus (730) Google Scholar , 3 Shapiro A.D. Nitric oxide signaling in plants. Vitam. Horm. 2005; 72: 339-398 Crossref PubMed Scopus (98) Google Scholar , 4 Corpas F.J. et al. Constitutive arginine-dependent nitric oxide synthase activity in different organs of pea seedlings during plant development. Planta. 2006; 224: 246-254 Crossref PubMed Scopus (239) Google Scholar ]. After the first report on the presence of NO in plant cells, many efforts have been made to elucidate the enzymatic sources of this versatile molecule. Although its main function is to catalyze the NAD(P)H-dependent reduction of nitrate to nitrite during nitrate assimilation, nitrate reductase was shown to generate NO [ 5 Yamasaki H. et al. An alternative pathway for nitric oxide production in plants: new features of an old enzyme. Trends Plant Sci. 1999; 4: 128-129 Abstract Full Text Full Text PDF PubMed Scopus (296) Google Scholar ]. The presence of NO-producing l-arginine-dependent nitric oxide synthase (NOS) activity has been demonstrated in various plant species [ 4 Corpas F.J. et al. Constitutive arginine-dependent nitric oxide synthase activity in different organs of pea seedlings during plant development. Planta. 2006; 224: 246-254 Crossref PubMed Scopus (239) Google Scholar , 6 del Río L.A. et al. Nitric oxide and nitric oxide synthase activity in plants. Phytochemistry. 2004; 65: 783-792 Crossref PubMed Scopus (256) Google Scholar , 7 Valderrama R. et al. Nitrosative stress in plants. FEBS Lett. 2007; 581: 453-461 Abstract Full Text Full Text PDF PubMed Scopus (280) Google Scholar ]. However, during the search for the gene encoding this activity, several proteins were erroneously identified as NOSs, including a variant of the P protein of the glycine decarboxylase complex and, more recently, the AtNOS1 protein [ 8 Zemojtel T. et al. Plant nitric oxide synthase: a never-ending story?. Trends Plant Sci. 2006; 11: 524-525 Abstract Full Text Full Text PDF PubMed Scopus (265) Google Scholar ]. This indicates that the complete identification of the enzymatic source(s) of NO remains an open question in our understanding of NO metabolism in plants. In comparison with NO, however, much less attention has been paid to other RNS, such as S-nitrosoglutathione (GSNO), nitrotyrosine (n-Tyr) and peroxynitrite, which all have a high physiological relevance, as has been demonstrated in animal systems [ 9 Klatt P. Lamas S. Regulation of protein function by S-glutathiolation in response to oxidative and nitrosative stress. Eur. J. Biochem. 2000; 267: 4928-4944 Crossref PubMed Scopus (654) Google Scholar , 10 Benhar M. et al. Nitrosative stress in the ER: a new role for S-nitrosylation in neurodegenerative diseases. ACS Chem. Biol. 2006; 1: 355-358 Crossref PubMed Scopus (72) Google Scholar ]. In plants, the identification of possible candidates for S-nitrosylation in Arabidopsis cell suspension cultures and in leaves by application of exogenous NO or GSNO has recently been reported [ 11 Lindermayr C. et al. Proteomic identification of S-nitrosylated proteins in Arabidopsis. Plant Physiol. 2005; 137: 921-930 Crossref PubMed Scopus (588) Google Scholar ].