title: Responses of barley root and shoot proteomes to long-term nitrogen deficiency, short-term nitrogen starvation and ammonium.
abstract: Cereals are major crops worldwide, and improvement of their nitrogen use efficiency is a crucial challenge. In this study proteins responding to N supply in barley roots and shoots were analysed using a proteomics approach, to provide insight into mechanisms of N uptake and assimilation. Control plants grown hydroponically for 33 d with 5 mm nitrate, plants grown under N deficiency (0.5 mm nitrate, 33 d) or short-term N starvation (28 d with 5 mm nitrate followed by 5 d with no N source) were compared. N deficiency caused changes in C and N metabolism and ascorbate-glutathione cycle enzymes in shoots and roots. N starvation altered proteins of amino acid metabolism in roots. Both treatments caused proteome changes in roots that could affect growth. Shoots of plants grown with ammonium as N source (28 d with 5 mm nitrate followed by 5 d with 5 mm ammonium) showed responses similar to N deficient shoots, characterized by turnover of ribulose 1·5-bisphosphate carboxylase/oxygenase (Rubisco) and increases in proteins of the chloroplastic transcription and translation machinery. Identified proteins in 67 and 49 varying spots in roots and shoots respectively, corresponded to 62 functions and over 80 gene products, considerably advancing knowledge of N responses in barley.
authors: Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Building 224, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark.
authors: Anders L B
authors: AL
authors: Møller
authors: Pai
authors: P
authors: Pedas
authors: Birgit
authors: B
authors: Andersen
authors: Birte
authors: B
authors: Svensson
authors: Jan K
authors: JK
authors: Schjoerring
authors: Christine
authors: C
authors: Finnie
mesh_terms: D001467:Hordeum / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D018520:Plant Shoots / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D020543:Proteome; D000644:Quaternary Ammonium Compounds; D009584:Nitrogen