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

FORESI, NOELIA; MAYTA, MARTIN L.; LODEYRO, ANABELLA F.; SCUFFI, DENISE; CORREA-ARAGUNDE, NATALIA; GARCÍA-MATA, CARLOS; CASALONGUÉ, CLAUDIA; CARRILLO, NESTOR; LAMATTINA, LORENZO

PLANT JOURNAL

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 32 p. 806 - 821

0960-7412

Nitric oxide (NO) is a signaling molecule with diverse biological functions in plants. NO plays a crucial rolein growth and development, from germination to senescence, and is also involved in plant responses to bioticand 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, orthe 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 (Ot-NOS) has been discovered and characterized. Arabidopsis thaliana plants were transformed with OtNOSunder 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 OtNOSaccumulated higher NO concentrations compared with siblings transformed with the empty vector, and displayedenhanced salt, drought and oxidative stress tolerance. Moreover, transgenic OtNOS lines exhibitedincreased stomatal development compared with plants transformed with the empty vector. Both in vitroand in vivo experiments indicate that OtNOS, unlike mammalian NOS, efficiently uses tetrahydrofolate as acofactor in Arabidopsis plants. The modulation of NO production to alleviate abiotic stress disturbances inhigher plants highlights the potential of genetic manipulation to influence NO metabolism as a tool toimprove plant fitness under adverse growth conditions.