title: Water deficit stress-induced changes in carbon and nitrogen partitioning in Chenopodium quinoa Willd.
abstract: Water deficit stress followed by re-watering during grain filling resulted in the induction of the ornithine pathway and in changes in Quinoa grain quality. The genetic diversity of Chenopodium quinoa Willd. (Quinoa) is accompanied by an outstanding environmental adaptability and high nutritional properties of the grains. However, little is known about the biochemical and physiological mechanisms associated with the abiotic stress tolerance of Quinoa. Here, we characterized carbon and nitrogen metabolic changes in Quinoa leaves and grains in response to water deficit stress analyzing their impact on the grain quality of two lowland ecotypes (Faro and BO78). Differences in the stress recovery response were found between genotypes including changes in the activity of nitrogen assimilation-associated enzymes that resulted in differences in grain quality. Both genotypes showed a common strategy to overcome water stress including the stress-induced synthesis of reactive oxygen species scavengers and osmolytes. Particularly, water deficit stress induced the stimulation of the ornithine and raffinose pathways. Our results would suggest that the regulation of C- and N partitioning in Quinoa during grain filling could be used for the improvement of the grain quality without altering grain yields.
authors.affiliation: Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Consorcio: Universidad de La Serena, INIA Intihuasi, Universidad Católica del Norte, Casilla 599, Coquimbo, Chile. luisa.bascunan@ceaza.cl.
authors.forename: Luisa
authors.initials: L
authors.lastname: Bascuñán-Godoy
authors.affiliation: Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Reguera
authors.affiliation: Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
authors.forename: Yasser M
authors.initials: YM
authors.lastname: Abdel-Tawab
authors.affiliation: Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Blumwald
mesh_terms: D002244:Carbon / Q000378:metabolism*; D027465:Chenopodium quinoa / Q000235:genetics / Q000502:physiology*; D003681:Dehydration; D002523:Edible Grain / Q000235:genetics / Q000502:physiology; D014644:Genetic Variation; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D013312:Stress, Physiological; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water; D002244:Carbon; D009584:Nitrogen
keywords: C and N partitioning; Grain nutritional quality; Ornithine pathway; Quinoa; ROS scavengers; Source and sink interactions; Stress recovery; Water deficit stress