title: Bread Wheat (Triticum aestivum L.) Grain Protein Concentration Is Related to Early Post-Flowering Nitrate Uptake under Putative Control of Plant Satiety Level.
abstract: The strong negative correlation between grain protein concentration (GPC) and grain yield (GY) in bread wheat complicates the simultaneous improvement of these traits. However, earlier studies have concluded that the deviation from this relationship (grain protein deviation or GPD) has strong genetic basis. Genotypes with positive GPD have an increased ability to uptake nitrogen (N) during the post-flowering period independently of the amount of N taken up before flowering, suggesting that genetic variability for N satiety could enable the breakage of the negative relationship. This study is based on two genotypes markedly contrasted for GPD grown under semi-hydroponic conditions differentiated for nitrate availability both before and after flowering. This allows exploration of the genetic determinants of post-flowering N uptake (PANU) by combining whole plant sampling and targeted gene expression approaches. The results highlights the correlation (r² = 0.81) with GPC of PANU occurring early during grain development (flowering-flowering + 250 degree-days) independently of GY. Early PANU was in turn correlated (r² = 0.80) to the stem-biomass increment after flowering through its effect on N sink activity. Differences in early PANU between genotypes, despite comparable N statuses at flowering, suggest that genetic differences in N satiety could be involved in the establishment of the GPC. Through its strong negative correlation with genes implied in N assimilation, root nitrate concentration appears to be a good marker for evaluating instantaneous plant N demand, and may provide valuable information on the genotypic N satiety level. This trait may help breeders to identify genotypes having high GPC independently of their GY.
authors.affiliation: INRA, UMR 1095 Génétique, Diversité et Ecophysiologie des Céréales, 5 chemin de Beaulieu, F-63100 Clermont-Ferrand, France.|Université Blaise Pascal, UMR 1095 Génétique, Diversité et Ecophysiologie des Céréales, F-63178 Aubière Cedex, France.|Arvalis-Institut du Végétal, Station Expérimentale de Boigneville, F-91720 Boigneville, France.
authors.forename: François
authors.initials: F
authors.lastname: Taulemesse
authors.affiliation: INRA, UMR 1095 Génétique, Diversité et Ecophysiologie des Céréales, 5 chemin de Beaulieu, F-63100 Clermont-Ferrand, France.|Université Blaise Pascal, UMR 1095 Génétique, Diversité et Ecophysiologie des Céréales, F-63178 Aubière Cedex, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Le Gouis
authors.affiliation: Arvalis-Institut du Végétal, Station Expérimentale de Boigneville, F-91720 Boigneville, France.
authors.forename: David
authors.initials: D
authors.lastname: Gouache
authors.affiliation: INRA, UMR 1332 Biologie du Fruit et Pathologie, 71 avenue Edouard Bourlaux, F-33882 Villenave d'Ornon Cedex, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Gibon
authors.affiliation: INRA, UMR 1095 Génétique, Diversité et Ecophysiologie des Céréales, 5 chemin de Beaulieu, F-63100 Clermont-Ferrand, France.|Université Blaise Pascal, UMR 1095 Génétique, Diversité et Ecophysiologie des Céréales, F-63178 Aubière Cedex, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Allard
mesh_terms: D018533:Biomass; D001939:Bread; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D014908:Triticum / Q000235:genetics*
chemical_list: D009566:Nitrates; D010940:Plant Proteins; D009584:Nitrogen