TY - JOUR A1 - Orawetz, Tom A1 - Malinova, Irina A1 - Orzechowski, Slawomir A1 - Fettke, Jörg T1 - Reduction of the plastidial phosphorylase in potato (Solanum tuberosum L.) reveals impact on storage starch structure during growth at low temperature JF - Plant physiology and biochemistry : an official journal of the Federation of European Societies of Plant Physiology N2 - Tubers of potato (Solanum tuberosum L.), one of the most important crops, are a prominent example for an efficient production of storage starch. Nevertheless, the synthesis of this storage starch is not completely understood. The plastidial phosphorylase (Phol; EC 2.4.11) catalyzes the reversible transfer of glucosyl residues from glucose-1-phosphate to the non-reducing end of alpha-glucans with the release of orthophosphate. Thus, the enzyme is in principle able to act during starch synthesis. However, so far under normal growth conditions no alterations in tuber starch metabolism were observed. Based on analyses of other species and also from in vitro experiments with potato tuber slices it was supposed, that Phol has a stronger impact on starch metabolism, when plants grow under low temperature conditions. Therefore, we analyzed the starch content, granule size, as well as the internal structure of starch granules isolated from potato plants grown under low temperatures. Besides wild type, transgenic potato plants with a strong reduction in the Phol activity were analyzed. No significant alterations in starch content and granule size were detected. In contrast, when plants were cultivated at low temperatures the chain length distributions of the starch granules were altered. Thus, the granules contained more short glucan chains. That was not observed in the transgenic plants, revealing that Pho1 in wild type is involved in the formation of the short glucan chains, at least at low temperatures. (C) 2016 Elsevier Masson SAS. All rights reserved. KW - Potato KW - Solanum tuberosum L. KW - Plastidial phosphorylase KW - Starch synthase KW - Starch metabolism KW - Starch granule Y1 - 2016 U6 - https://doi.org/10.1016/j.plaphy.2016.01.013 SN - 0981-9428 VL - 100 SP - 141 EP - 149 PB - Elsevier CY - Paris ER - TY - JOUR A1 - Mahlow, Sebastian A1 - Orzechowski, Slawomir A1 - Fettke, Jörg T1 - Starch phosphorylation: insights and perspectives JF - Cellular and molecular life sciences N2 - During starch metabolism, the phosphorylation of glucosyl residues of starch, to be more precise of amylopectin, is a repeatedly observed process. This phosphorylation is mediated by dikinases, the glucan, water dikinase (GWD) and the phosphoglucan, water dikinase (PWD). The starch-related dikinases utilize ATP as dual phosphate donor transferring the terminal gamma-phosphate group to water and the beta-phosphate group selectively to either C6 position or C3 position of a glucosyl residue within amylopectin. By the collaborative action of both enzymes, the initiation of a transition of alpha-glucans from highly ordered, water-insoluble state to a less order state is realized and thus the initial process of starch degradation. Consequently, mutants lacking either GWD or PWD reveal a starch excess phenotype as well as growth retardation. In this review, we focus on the increased knowledge collected over the last years related to enzymatic properties, the precise definition of the substrates, the physiological implications, and discuss ongoing questions. KW - Starch metabolism KW - Glucan, water dikinase KW - Phosphoglucan, water dikinase KW - Starch phosphorylation KW - Starch degradation Y1 - 2016 U6 - https://doi.org/10.1007/s00018-016-2248-4 SN - 1420-682X SN - 1420-9071 VL - 73 SP - 2753 EP - 2764 PB - Springer CY - Basel ER - TY - JOUR A1 - Krasuska, Urszula A1 - Ciacka, Katarzyna A1 - Orzechowski, Slawomir A1 - Fettke, Jörg A1 - Bogatek, Renata A1 - Gniazdowska, Agnieszka T1 - Modification of the endogenous NO level influences apple embryos dormancy by alterations of nitrated and biotinylated protein patterns JF - Planta N2 - NO donors and Arg remove dormancy of apple embryos and stimulate germination. Compounds lowering NO level (cPTIO, L -NAME, CAN) strengthen dormancy. Embryo transition from dormancy state to germination is linked to increased nitric oxide synthase (NOS)-like activity. Germination of embryos is associated with declined level of biotin containing proteins and nitrated proteins in soluble protein fraction of root axis. Pattern of nitrated proteins suggest that storage proteins are putative targets of nitration. Nitric oxide (NO) acts as a key regulatory factor in removal of seed dormancy and is a signal necessary for seed transition from dormant state into germination. Modulation of NO concentration in apple (Malus domestica Borkh.) embryos by NO fumigation, treatment with NO donor (S-nitroso-N-acetyl-d,l-penicillamine, SNAP), application of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), N (omega)-nitro-l-arginine methyl ester (l-NAME), canavanine (CAN) or arginine (Arg) allowed us to investigate the NO impact on seed dormancy status. Arg analogs and NO scavenger strengthened embryo dormancy by lowering reactive nitrogen species level in embryonic axes. This effect was accompanied by strong inhibition of NOS-like activity, without significant influence on tissue NO2 (-) concentration. Germination sensu stricto of apple embryos initiated by dormancy breakage via short term NO treatment or Arg supplementation were linked to a reduced level of biotinylated proteins in root axis. Decrease of total soluble nitrated proteins was observed at the termination of germination sensu stricto. Also modulation of NO tissue status leads to modification in nitrated protein pattern. Among protein bands that correspond to molecular mass of approximately 95 kDa, storage proteins (legumin A-like and seed biotin-containing protein) were identified, and can be considered as good markers for seed dormancy status. Moreover, pattern of nitrated proteins suggest that biotin containing proteins are also targets of nitration. KW - Apple KW - Nitro-tyrosine KW - Nitric oxide synthase-like activity KW - Reactive nitrogen species KW - Seed germination Y1 - 2016 U6 - https://doi.org/10.1007/s00425-016-2553-z SN - 0032-0935 SN - 1432-2048 VL - 244 SP - 877 EP - 891 PB - Springer CY - New York ER - TY - JOUR A1 - Gietler, Marta A1 - Nykiel, Malgorzata A1 - Orzechowski, Slawomir A1 - Zagdanska, Barbara A1 - Fettke, Jörg T1 - Proteomic analysis of S-nitrosylated and S-glutathionylated proteins in wheat seedlings with different dehydration tolerances JF - Plant physiology and biochemistry : an official journal of the Federation of European Societies of Plant Physiology N2 - A loss of dehydration tolerance in wheat seedlings on the fifth day following imbibition is associated with a disturbance in cellular redox homeostasis, as documented by a shift of the reduced/oxidized glutathione ratio to a more oxidized state and a significant increase in the ratio of protein thiols to the total thiol group content. Therefore, the identification and characterization of redox-sensitive proteins are important steps toward understanding the molecular mechanisms of the loss of dehydration tolerance. In the present study, proteins that were differentially expressed between fully turgid (control), dehydrated tolerant (four-day-old) and dehydrated sensitive (six-day-old) wheat seedlings were analysed. Protein spots having at least a significant (p < 0.05) two-fold change in protein abundance were selected by Delta2D as differentially expressed, identified by MALDI-TOF and LC-MS/MS, and classified according to their function. The observed changes in the proteomic patterns of the differentially S-nitrosylated and S-glutathionylated proteins were highly specific in dehydration-tolerant and-sensitive wheat seedlings. The metabolic function of these proteins indicates that dehydration tolerance is mainly related to nucleic acids, protein metabolism, and energy metabolism. It has been proven that leaf-specific thionins BTH6 and DB4, chloroplastic 50S ribosomal protein L16, phospholipase A1-II delta, and chloroplastic thioredoxin M2 are both S-nitrosylated and S-glutathionylated upon water deficiency. Our results revealed the existence of interplay between S-nitrosylation and S-glutathionylation, two redox-regulated protein posttranslational modifications that could enhance plant defence mechanisms and/or facilitate the acclimation of plants to unfavourable environmental conditions. (C) 2016 Elsevier Masson SAS. All rights reserved. KW - Dehydration tolerance KW - Proteomics KW - Redox sensitive proteins KW - S-glutathionylation KW - S-nitrosylation KW - Triticum aestivum L. Y1 - 2016 U6 - https://doi.org/10.1016/j.plaphy.2016.08.017 SN - 0981-9428 VL - 108 SP - 507 EP - 518 PB - Elsevier CY - Paris ER -