title: Apocynin-induced nitric oxide production confers antioxidant protection in maize leaves.
abstract: The effect of apocynin on nitric oxide (NO) synthesis and oxidative stress was studied in corn (Zea mays) seedlings. After treatment with 100 microM apocynin, strongly increased amounts of NO were detected in the leaves. This NO production was reduced by more than 70% by N(G)-nitro-l-arginine methyl ester (L-NAME), a NO synthase (NOS) inhibitor, but there was no reduction in NO production when apocynin was applied in combination with diphenylene iodonium (a plant NOX inhibitor). When maize seedlings were UV-B-irradiated, cellular damage occurred and reactive oxygen species (ROS) were found widely distributed in chloroplasts and mesophyll cells. Pre-treatment with apocynin and coinciding NO accumulation prevented this damage. However, the protective effect was averted by L-NAME application. Leaf discs placed in 1M H(2)O(2) for 24h showed a reduction in chlorophyll content that could also be avoided by apocynin treatment. Our results show that apocynin induces the accumulation of NO in leaves of maize seedlings through a NOS-like activity, a mechanism alternative to NOX inhibition, and confers an augmented tolerance to different types of abiotic oxidative stress. Indeed, we propose the use of apocynin as an alternative approach to study NO functionality in plants.
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC1245 (7600) Mar del Plata, Argentina.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Tossi
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC1245 (7600) Mar del Plata, Argentina. Electronic address: rocassia@mdp.edu.ar.
authors.forename: Raúl
authors.initials: R
authors.lastname: Cassia
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC1245 (7600) Mar del Plata, Argentina.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Lamattina
mesh_terms: D000098:Acetophenones / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000528:radiation effects; D018515:Plant Leaves / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects; D014466:Ultraviolet Rays; D003313:Zea mays / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D000098:Acetophenones; D000975:Antioxidants; D002734:Chlorophyll; D009569:Nitric Oxide; C056165:acetovanillone; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase