title: Nitric oxide is required for determining root architecture and lignin composition in sunflower. Supporting evidence from microarray analyses.
abstract: Nitric oxide (NO) is a signal molecule involved in several physiological processes in plants, including root development. Despite the importance of NO as a root growth regulator, the knowledge about the genes and metabolic pathways modulated by NO in this process is still limited. A constraint to unravel these pathways has been the use of exogenous applications of NO donors that may produce toxic effects. We have analyzed the role of NO in root architecture through the depletion of endogenous NO using the scavenger cPTIO. Sunflower seedlings growing in liquid medium supplemented with cPTIO showed unaltered primary root length while the number of lateral roots was deeply reduced; indicating that endogenous NO participates in determining root branching in sunflower. The transcriptional changes induced by NO depletion have been analyzed using a large-scale approach. A microarray analysis showed 330 genes regulated in the roots (p≤0.001) upon endogenous NO depletion. A general cPTIO-induced up-regulation of genes involved in the lignin biosynthetic pathway was observed. Even if no detectable changes in total lignin content could be detected, cell walls analyses revealed that the ratio G/S lignin increased in roots treated with cPTIO. This means that endogenous NO may control lignin composition in planta. Our results suggest that a fine tuning regulation of NO levels could be used by plants to regulate root architecture and lignin composition. The functional implications of these findings are discussed.
authors.affiliation: Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina. Electronic address: cortimonzon@mdp.edu.ar.
authors.forename: Georgina
authors.initials: G
authors.lastname: Corti Monzón
authors.affiliation: Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina. Electronic address: mpinedo@mdp.edu.ar.
authors.forename: Marcela
authors.initials: M
authors.lastname: Pinedo
authors.affiliation: Cátedra de Estadística y Biometría, Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Córdoba, Argentina. Electronic address: dirienzo.julio@gmail.com.
authors.forename: Julio
authors.initials: J
authors.lastname: Di Rienzo
authors.affiliation: Departamento de Biología Vegetal, Universidad de Murcia, Murcia, Spain. Electronic address: enovo@udc.es.
authors.forename: Esther
authors.initials: E
authors.lastname: Novo-Uzal
authors.affiliation: Departamento de Biología Animal, Biología Vegetal y Ecología, Universidade da Coruña, A Coruña, Spain. Electronic address: fpomar@udc.es.
authors.forename: Federico
authors.initials: F
authors.lastname: Pomar
authors.affiliation: Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina. Electronic address: lolama@mdp.edu.ar.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Lamattina
authors.affiliation: Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina. Electronic address: ldelacan@mdp.edu.ar.
authors.forename: Laura
authors.initials: L
authors.lastname: de la Canal
mesh_terms: D016166:Free Radical Scavengers / Q000494:pharmacology; D020869:Gene Expression Profiling; D006368:Helianthus / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D008031:Lignin / Q000032:analysis / Q000737:chemistry; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D020030:Nitric Oxide Donors; D010940:Plant Proteins; D009569:Nitric Oxide; D008031:Lignin
keywords: Lignin; Microarray; Nitric oxide; Phenylpropanoid biosynthesis; Root architecture; cPTIO