Responses of barley root and shoot proteomes to long‐term nitrogen deficiency, short‐term nitrogen starvation and ammonium

• Published in: Plant, cell and environment cell and environment, 2011-12, Vol.34 (12), p.2024-2037
• Main Authors: MØLLER, ANDERS L. B., PEDAS, PAI, ANDERSEN, BIRGIT, SVENSSON, BIRTE, SCHJOERRING, JAN K., FINNIE, CHRISTINE
• Format: Article
• Language: English
• Subjects: amino acid metabolism; Amino acids; Ammonium; ascorbate‐glutathione cycle; Biological and medical sciences; carbon metabolism; Crops; Enzymes; Fundamental and applied biological sciences. Psychology; Hordeum - metabolism; Hordeum vulgare; hydroponics; mass spectrometry; Metabolism; nitrate; Nitrates; Nitrogen; Nitrogen - metabolism; Plant Roots - metabolism; Plant Shoots - metabolism; Proteins; Proteome - metabolism; proteome analysis; Proteomics; Quaternary Ammonium Compounds - metabolism; redox regulation; shoots; Stress, Physiological; two‐dimensional gel electrophoresis
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/j.1365-3040.2011.02396.x

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. Improvement of nitrogen use efficiency of important cereal crops is a crucial challenge. In this study a proteomics approach enabled identification of over 80 proteins in barley roots and shoots that respond to N supply. Distinct but overlapping responses to long term N deficiency, short‐term N starvation and ammonium were observed, which differed in roots and shoots.