title: Expression of the tetrahydrofolate-dependent nitric oxide synthase from the green alga Ostreococcus tauri increases tolerance to abiotic stresses and influences stomatal development in Arabidopsis.
abstract: Nitric oxide (NO) is a signaling molecule with diverse biological functions in plants. NO plays a crucial role in growth and development, from germination to senescence, and is also involved in plant responses to biotic and abiotic stresses. In animals, NO is synthesized by well-described nitric oxide synthase (NOS) enzymes. NOS activity has also been detected in higher plants, but no gene encoding an NOS protein, or the enzymes required for synthesis of tetrahydrobiopterin, an essential cofactor of mammalian NOS activity, have been identified so far. Recently, an NOS gene from the unicellular marine alga Ostreococcus tauri (OtNOS) has been discovered and characterized. Arabidopsis thaliana plants were transformed with OtNOS under the control of the inducible short promoter fragment (SPF) of the sunflower (Helianthus annuus) Hahb-4 gene, which responds to abiotic stresses and abscisic acid. Transgenic plants expressing OtNOS accumulated higher NO concentrations compared with siblings transformed with the empty vector, and displayed enhanced salt, drought and oxidative stress tolerance. Moreover, transgenic OtNOS lines exhibited increased stomatal development compared with plants transformed with the empty vector. Both in vitro and in vivo experiments indicate that OtNOS, unlike mammalian NOS, efficiently uses tetrahydrofolate as a cofactor in Arabidopsis plants. The modulation of NO production to alleviate abiotic stress disturbances in higher plants highlights the potential of genetic manipulation to influence NO metabolism as a tool to improve plant fitness under adverse growth conditions.
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
authors.forename: Noelia
authors.initials: N
authors.lastname: Foresi
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000, Rosario, Argentina.
authors.forename: Martín L
authors.initials: ML
authors.lastname: Mayta
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000, Rosario, Argentina.
authors.forename: Anabella F
authors.initials: AF
authors.lastname: Lodeyro
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
authors.forename: Denise
authors.initials: D
authors.lastname: Scuffi
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
authors.forename: Natalia
authors.initials: N
authors.lastname: Correa-Aragunde
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
authors.forename: Carlos
authors.initials: C
authors.lastname: García-Mata
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
authors.forename: Claudia
authors.initials: C
authors.lastname: Casalongué
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000, Rosario, Argentina.
authors.forename: Néstor
authors.initials: N
authors.lastname: Carrillo
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Lamattina
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D000460:Chlorophyta / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000235:genetics; D006368:Helianthus / Q000235:genetics; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D054046:Plant Stomata / Q000235:genetics / Q000254:growth & development*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000235:genetics*; D013763:Tetrahydrofolates / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D013763:Tetrahydrofolates; D009569:Nitric Oxide; C030371:5,6,7,8-tetrahydrofolic acid; D012965:Sodium Chloride; D000040:Abscisic Acid; D019001:Nitric Oxide Synthase
keywords: Arabidopsis thaliana; abiotic stress; nitric oxide; nitric oxide synthase; oxidative stress; stomatal index; tetrahydrofolate