Prof. Dr. rer. nat. Prof. Dr. rer. nat. Bernhard Grimm

Profil

• A Regulatory Crosstalk Between Organelles and Nucleus in Plant Cells

  Quelle ↗

  Zeitraum: 09/2013 - 12/2015 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Chlorophyll Stabilisation

  Quelle ↗

  Zeitraum: 04/2007 - 12/2007 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Chlorophyll-Stabilisation

  Quelle ↗

  Zeitraum: 07/2006 - 07/2008 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems

  Quelle ↗

  Förderer: Bundesministerium für Forschung, Technologie und Raumfahrt Zeitraum: 03/2019 - 02/2024 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Die Funktion von co-translationalen N-terminalen Modifikationen plastidenkodierter Proteine unter Stresseinfluss

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 01/2021 - 12/2024 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Differentielle Funktionen der NF-Y-Untereinheiten für die Transkriptionskontrolle für oxidative Stressabwehr und Photosynthese

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 12/2004 - 12/2006 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Durch photosensiblisierende Porphyrine induzierte Geneexpression

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 11/2005 - 12/2006 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• FG 2092/1: Biogenesis of Thylakoid Membranes – Neue Proteine für die Protein-Protein-Interaktion und Organisation der Chlorophyllbiosynthese und der Verbindung zum Assemblierungsprozess der Chlorophyll-bindenden Proteine in der Photosynthese (TP 03)

  Quelle ↗

  Förderer: DFG Forschungsgruppe Zeitraum: 05/2014 - 12/2018 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• FG 804: Retrograde Signaling in plants 'Central Task'

  Quelle ↗

  Förderer: DFG Forschungsgruppe Zeitraum: 05/2007 - 12/2011 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• FG 804: Retrograde Signaling in Plants - Teilprojekt 2: Dissection of the tetrapyrrole-mediated signaling pathway: Identification of componenets involved in signal transduction and of target genes

  Quelle ↗

  Förderer: DFG Forschungsgruppe Zeitraum: 05/2007 - 04/2010 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• FG 804: Retrograde Signaling in Plants – TP 2: Dissection of the Tetrapyrrole-Mediated Signaling Pathway: Identification of Components Involved in Signal Transduction and of Target Genes

  Quelle ↗

  Förderer: DFG Forschungsgruppe Zeitraum: 11/2010 - 08/2014 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• FOR 2092/2: Assistenzproteine für die Protein-Protein-Interaktion und Organisation der Chlorophyllbiosynthese sowie die Assemblierung von Chlorophyll in Chlorophyll-bindende Proteine der Photosynthese (TP 03)

  Quelle ↗

  Förderer: DFG Forschungsgruppe Zeitraum: 11/2017 - 12/2021 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Förderung eines deutsch-russischen Symposiums (Veranstaltung: 12.09.-16.09.07, Minsk)

  Quelle ↗

  Förderer: DFG sonstige Programme Zeitraum: 09/2007 - 09/2007 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Functional analysis of the NF-Y transcription factor family for gene activation during adaptation to environmental stress. Exploration of properties and functions of specific members of NF-Y family for gene activation during adaptation to environmental

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 03/2007 - 12/2010 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Identification and Analysis of Chlamydomonas Mutants With Defects in Chlorophyll Synthesis

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 10/2011 - 09/2015 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Identifizierung und Analyse von Genen für den Tetrapyrrolstoffwechsel und die plastidären durch reaktive Sauerstoffspezies vermittelten Signalwege in Chlamydomonas reinhardtii

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 07/2019 - 07/2021 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Identifizierung und Analyse von Mutanten in der Chlorophyllbiosynthese der Grünalge Chlamydomonas reinhardtii

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 12/2008 - 11/2010 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Identifizierung von Proteinen, die am Häm-Transport von Plastiden ins Zytoplasma beteiligt sind.

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 09/2025 - 08/2027 Projektleitung: Prof. Dr. Christian Schmitz-Linneweber, Prof. Dr. rer. nat. Bernhard Grimm

• InnoLight

  Quelle ↗

  Zeitraum: 05/2013 - 10/2014 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• In-Planta-Analysen der drei Aradidopsis Isoformen des bifunktionalen RIBA Proteins mit katalytischen Domänen für GTP Cyclohydrolase II und 3,4-Dihydroxy-2-Butanon-4-Phosphat-Synthase

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 09/2014 - 02/2019 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• In-Vivo-Analyse funktioneller Domänen der pflanzlichen Glutamyl-tRNA-Reduktase, dem regulatorischen Schlüsselenzym der Tetrapyrrolbiosynthese

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 04/2011 - 03/2014 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Lieferung verschiedener Proteine

  Quelle ↗

  Förderer: Wirtschaftsunternehmen / gewerbliche Wirtschaft Zeitraum: 08/2015 - 08/2016 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Mutant screen in Chlamydomonas

  Quelle ↗

  Förderer: DFG sonstige Programme Zeitraum: 03/2010 - 02/2011 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Plastidenextrakte

  Quelle ↗

  Förderer: Wirtschaftsunternehmen / gewerbliche Wirtschaft Zeitraum: 11/2015 - 11/2015 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• SFB 429 II-III: Regulation des ratenlimitierenden Schritts der Bildung der 5-Aminolävulinsäure für Tetrapyrrolbiosynthese und Funktion des Chloroplasten (Teilprojekt B 9)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 01/2002 - 12/2010 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• SFB 429 II-III: Struktur und Funktion von Produkten konservierter plastidärer Leserahmen aus Synechocystis sp. PCC6803 (Teilprojekt A 8)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 01/2002 - 12/2010 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• SFB/TRR 175/1: Die Bedeutung der Phosphorylierung des GUN4-Proteins für Akklimatisierung, retrograde Signaltransreduktion und Tetrapyrrolbiosynthese (TP C04)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 07/2016 - 12/2020 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• SFB/TRR 175/2: Der Chloroplast als zentraler Knotenpunkt der Akklimatisation bei Pflanzen (TP C04)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 07/2020 - 06/2024 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• SPP 1710/2: Thiol-basierte Kontrolle des Tetrapyrrolstoffwechsels: Posttranslationale Kontrolle der Tetrapyrrolbiosyntheseenzyme durch NADPH-abhängige Thioredoxin-Reduktase C und Thioredoxine

  Quelle ↗

  Förderer: DFG Schwerpunktprogramm Zeitraum: 07/2017 - 01/2021 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Thiol-basierte Kontrolle des Tetrapyrrolstoffwechsels: Posttranslationale Kontrolle der NADPH-abhängigen Thioredoxin-Reduktase C auf Enzyme der Tetrapyrrolbiosynthese

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 04/2014 - 12/2018 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Untersuchungen zur Regulation der am Chlorophyll-Abbauweg beteiligten Enzyme

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 07/2005 - 06/2010 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Verminderung des Chlorophyllgehaltes in Ölpflanzensamen

  Quelle ↗

  Förderer: Bundesministerium für Forschung, Technologie und Raumfahrt Zeitraum: 04/2002 - 03/2005 Projektleitung: Prof. Dr. rer. nat. Bernhard Grimm

• Step Systems GmbH

  PT

  7 Treffer75.8%
  • CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
    T

    75.8%

• Conviron

  PT

  7 Treffer75.8%
  • CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
    T

    75.8%

• Biologische Beratung

  PT

  7 Treffer75.8%
  • CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
    T

    75.8%

• Gesellschaft für soziale Unternehmensberatung mbH

  PT

  7 Treffer75.8%
  • CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
    T

    75.8%

• Rewe Group

  PT

  7 Treffer75.8%
  • CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
    T

    75.8%

• Vereniging voor Christelijk Hoger Onderwijs Wetenschappelijk Onderzoek en Patientenzorg

  PT

  32 Treffer61.2%
  • Eukaryotic Unicellular Organism Biology – Systems Biology of the Control of Cell Growth and Proliferation
    P

    61.2%

• Science & Startups Berlin

  T

  30 Treffer56.4%
  • Zuwendung im Rahmen des Programms „exist – Existenzgründungen aus der Wissenschaft“ aus dem Bundeshaushalt, Einzelplan 09, Kapitel 02, Titel 68607, Haushaltsjahr 2026, sowie aus Mitteln des Europäischen Strukturfonds (hier Euro-päischer Sozialfonds Plus – ESF Plus) Förderperiode 2021-2027 – Kofinanzierung für das Vorhaben: „exist Women“
    T

    56.4%

• Asociación Centro de Investigación Cooperativa en Nanociencia – CIC nanoGUNE

  PT

  145 Treffer55.6%
  • DYnamic control in hybrid plasmonic NAnopores: road to next generation multiplexed single MOlecule detection
    P

    55.6%

• Landeskompetenzzentrum Forst Eberswalde

  PT

  177 Treffer55.3%
  • ILB: Entwicklung eines Produktions- und Pflanzverfahrens mit rohrförmigen Wurzelhüllen
    P

    55.3%
  • Entwicklung eines innovativen Kulturbegründungsverfahrens für Eichen zur Verbesserung der Wurzelentwicklung durch kompostierbare Wurzelhüllen
    P

    47.9%

• Isogen GmbH & Co KG

  PT

  69 Treffer54.5%
  • Bewertung der physiologischen Plastizität und genetischen Variabilität der Kiefer (Pinus sylvestris L.) an ihrer westlichen Verbreitungsgrenze unter den Bedingungen des Klimawandels
    T

    54.5%

• Recent advances in chlorophyll biosynthesis and breakdown in higher plants

  2004

  Plant Molecular Biology · 412 Zitationen · DOI

• Differential response of antioxidant compounds to salinity stress in salt‐tolerant and salt‐sensitive seedlings of foxtail millet (<i>Setaria italica</i>)

  2000

  Physiologia Plantarum · 367 Zitationen · DOI

  The modulation of antioxidant components was comparatively analysed in a salt‐tolerant (cv. Prasad) and salt‐sensitive (cv. Lepakshi) cultivar of foxtail millet ( Setaria italica L.) under different NaCl concentrations. Under conditions of salt stress, the salt‐tolerant cultivar exhibited increased total superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity, whereas both enzyme activities decreased in acutely salt‐stressed seedlings of the sensitive cultivar. At 200 m M NaCl, the tolerant foxtail millet cultivar responded with induction of cytosolic Cu/Zn‐SOD and the Mn‐SOD isoform at the protein level. The induced accumulation of the cytosolic Cu/Zn‐SOD protein/activity is positively correlated with an elevated level of the cytosolic APX gene activity. The elevated cytosolic Cu/Zn‐SOD and cytosolic APX activity correlates with an induced accumulation of their transcripts. Tolerant 5‐day‐old seedlings grown during high salinity treatment (200 m M NaCl) contained a lower amount of Na + ions and showed a lower electrolyte leakage than sensitive seedlings. In conclusion, our comparative studies indicate that salt‐induced oxidative tolerance is conferred by an enhanced compartment‐specific activity of the antioxidant enzymes in response to compartment‐specific signals.

• The cell biology of tetrapyrroles: a life and death struggle

  2010

  Trends in Plant Science · 314 Zitationen · DOI

• Chlorophylls and Bacteriochlorophylls: Biochemistry, Biophysics, Functions and Applications

  2005

  Open access LMU (Ludwid Maxmilian's Universitat Munchen) · 298 Zitationen · DOI

  Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1.Please, click on the respective files for downloading. Any reference should cite the full title of the book.

• Chlorophylls and Bacteriochlorophylls

  2006

  Advances in photosynthesis and respiration · 277 Zitationen · DOI

• Regulation and function of tetrapyrrole biosynthesis in plants and algae

  2015

  Biochimica et Biophysica Acta (BBA) - Bioenergetics · 249 Zitationen · DOI

• Connecting Chlorophyll Metabolism with Accumulation of the Photosynthetic Apparatus

  2021

  Trends in Plant Science · 241 Zitationen · DOI

• The light stress‐induced protein ELIP2 is a regulator of chlorophyll synthesis in <i>Arabidopsis thaliana</i>

  2007

  The Plant Journal · 183 Zitationen · DOI

  The early light-induced proteins (ELIPs) belong to the multigenic family of pigment-binding light-harvesting complexes. ELIPs accumulate transiently and are believed to play a protective role in plants exposed to high levels of light. Constitutive expression of the ELIP2 gene in Arabidopsis resulted in a marked reduction of the pigment content of the chloroplasts, both in mature leaves and during greening of etiolated seedlings. The chlorophyll loss was associated with a decrease in the number of photosystems in the thylakoid membranes, but the photosystems present were fully assembled and functional. A detailed analysis of the chlorophyll-synthesizing pathway indicated that ELIP2 accumulation downregulated the level and activity of two important regulatory steps: 5-aminolevulinate synthesis and Mg-protoporphyrin IX (Mg-Proto IX) chelatase activity. The contents of glutamyl tRNA reductase and Mg chelatase subunits CHLH and CHLI were lowered in response to ELIP2 accumulation. In contrast, ferrochelatase activity was not affected and the inhibition of Heme synthesis was null or very moderate. As a result of reduced metabolic flow from 5-aminolevulinic acid, the steady state levels of various chlorophyll precursors (from protoporphyrin IX to protochlorophyllide) were strongly reduced in the ELIP2 overexpressors. Taken together, our results indicate that the physiological function of ELIPs could be related to the regulation of chlorophyll concentration in thylakoids. This seems to occur through an inhibition of the entire chlorophyll biosynthesis pathway from the initial precursor of tetrapyrroles, 5-aminolevulinic acid. We suggest that ELIPs work as chlorophyll sensors that modulate chlorophyll synthesis to prevent accumulation of free chlorophyll, and hence prevent photooxidative stress.

• Cloning and characterization of a plastidal and a mitochondrial isoform of tobacco protoporphyrinogen IX oxidase

  1997

  Proceedings of the National Academy of Sciences · 183 Zitationen · DOI

  Protoporphyrinogen IX oxidase is the last enzyme in the common pathway of heme and chlorophyll synthesis and provides precursor for the mitochondrial and plastidic heme synthesis and the predominant chlorophyll synthesis in plastids. We cloned two different, full-length tobacco cDNA sequences by complementation of the protoporphyrin-IX-accumulating Escherichia coli hemG mutant from heme auxotrophy. The two sequences show similarity to the recently published Arabidopsis PPOX, Bacillus subtilis hemY, and to mammalian sequences encoding protoporphyrinogen IX oxidase. One cDNA sequence encodes a 548-amino acid residues protein with a putative transit sequence of 50 amino acid residues, and the second cDNA encodes a protein of 504 amino acid residues. Both deduced protein sequences share 27.2% identical amino acid residues. The first in vitro translated protoporphyrinogen IX oxidase could be translocated to plastids, and the approximately 53-kDa mature protein was detected in stroma and membrane fraction. The second enzyme was targeted to mitochondria without any detectable reduction in size. Localization of both enzymes in subcellular fractions was immunologically confirmed. Steady-state RNA analysis indicates an almost synchronous expression of both genes during tobacco plant development, greening of young seedlings, and diurnal and circadian growth. The mature plastidal and the mitochondrial isoenzyme were overexpressed in E. coli. Bacterial extracts containing the recombinant mitochondrial enzyme exhibit high protoporphyrinogen IX oxidase activity relative to control strains, whereas the plastidal enzyme could only be expressed as an inactive peptide. The data presented confirm a compartmentalized pathway of tetrapyrrole synthesis with protoporphyrinogen IX oxidase in plastids and mitochondria.

• Role of Magnesium Chelatase Activity in the Early Steps of the Tetrapyrrole Biosynthetic Pathway

  2000

  PLANT PHYSIOLOGY · 182 Zitationen · DOI

  Magnesium-protoporphyrin IX chelatase (Mg-chelatase) is located at the branchpoint of tetrapyrrole biosynthesis, at which point protoporphyrin IX is distributed for the synthesis of chlorophyll and heme. We investigated the regulatory contribution of Mg-chelatase to the flow of metabolites. In plants, the enzyme complex consists of three subunits, designated CHL D, CHL I, and CHL H. Transgenic tobacco (Nicotiana tabacum) plants expressing antisense RNA for the Mg-chelatase subunit CHL H were analyzed to elucidate further the role of Mg-chelatase in the distribution of protoporphyrin IX into the branched tetrapyrrolic pathway. The transgenic plants displayed a reduced growth rate and chlorophyll deficiency. Both phenotypical properties were correlated with lower Mg-chelatase activity. Unexpectedly, less protoporphyrin IX and heme accumulated, and a decrease in 5-aminolevulinate (ALA)-synthesizing capacity and ALA dehydratase activity paralleled the progressive reduction in Mg-chelatase activity in the transformants compared with control plants. The reduced activities of the early enzymatic steps corresponded with lower levels of transcripts encoding glutamyl-tRNA reductase and ALA-dehydratase. The decreased expression and activities of early enzymes in the pathway could be explained by a feedback-controlled mechanism in response to lower Mg-chelatase activity. We discuss intercompartmental signaling that synchronizes the activities of the first steps in tetrapyrrolic metabolism with the late steps for the synthesis of end products.

• Reduced Activity of Geranylgeranyl Reductase Leads to Loss of Chlorophyll and Tocopherol and to Partially Geranylgeranylated Chlorophyll in Transgenic Tobacco Plants Expressing Antisense RNA for Geranylgeranyl Reductase1

  1999

  PLANT PHYSIOLOGY · 180 Zitationen · DOI

  The enzyme geranylgeranyl reductase (CHL P) catalyzes the reduction of geranylgeranyl diphosphate to phytyl diphosphate. We identified a tobacco (Nicotiana tabacum) cDNA sequence encoding a 52-kD precursor protein homologous to the Arabidopsis and bacterial CHL P. The effects of deficient CHL P activity on chlorophyll (Chl) and tocopherol contents were studied in transgenic plants expressing antisense CHL P RNA. Transformants with gradually reduced Chl P expression showed a delayed growth rate and a pale or variegated phenotype. Transformants grown in high (500 &mgr;mol m-2 s-1; HL) and low (70 &mgr;mol photon m-2 s-1; LL) light displayed a similar degree of reduced tocopherol content during leaf development, although growth of wild-type plants in HL conditions led to up to a 2-fold increase in tocopherol content. The total Chl content was more rapidly reduced during HL than LL conditions. Up to 58% of the Chl content was esterified with geranylgeraniol instead of phytol under LL conditions. Our results indicate that CHL P provides phytol for both tocopherol and Chl synthesis. The transformants are a valuable model with which to investigate the adaptation of plants with modified tocopherol levels against deleterious environmental conditions.

• Cytokinin deficiency causes distinct changes of sink and source parameters in tobacco shoots and roots

  2008

  Journal of Experimental Botany · 179 Zitationen · DOI

  Cytokinin deficiency causes pleiotropic developmental changes such as reduced shoot and increased root growth. It was investigated whether cytokinin-deficient tobacco plants, which overproduce different cytokinin oxidase/dehydrogenase enzymes, show changes in different sink and source parameters, which could be causally related to the establishment of the cytokinin deficiency syndrome. Ultrastructural analysis revealed distinct changes in differentiating shoot tissues, including an increased vacuolation and an earlier differentiation of plastids, which showed partially disorganized thylakoid structures later in development. A comparison of the ploidy levels revealed an increased population of cells with a 4C DNA content during early stages of leaf development, indicating an inhibited progression from G2 to mitosis. To compare physiological characteristics of sink leaves, source leaves and roots of wild-type and cytokinin-deficient plants, several photosynthetic parameters, content of soluble sugars, starch and adenylates, as well as activities of enzymes of carbon assimilation and dissimilation were determined. Leaves of cytokinin-deficient plants contained less chlorophyll and non-photochemical quenching of young leaves was increased. However, absorption rate, photosynthetic capacity (F(v)/F(m) and J(CO2 max)) and efficiency (Phi CO(2 app)), as well as the content of soluble sugars, were not strongly altered in source leaves, indicating that chlorophyll is not limiting for photoassimilation and suggesting that source strength did not restrict shoot growth. By contrast, shoot sink tissues showed drastically reduced contents of soluble sugars, decreased activities of vacuolar invertases, and a reduced ATP content. These results strongly support a function of cytokinin in regulating shoot sink strength and its reduction may be a cause of the altered shoot phenotype. Roots of cytokinin-deficient plants contained less sugar compared with wild-type. However, this did not negatively affect glycolysis, ATP content, or root development. It is suggested that cytokinin-mediated regulation of the sink strength differs between roots and shoots.

• Tetrapyrrole biosynthetic enzyme protoporphyrinogen IX oxidase 1 is required for plastid RNA editing

  2014

  Proceedings of the National Academy of Sciences · 158 Zitationen · DOI

  RNA editing is a posttranscriptional process that covalently alters the sequence of RNA molecules and plays important biological roles in both animals and land plants. In flowering plants, RNA editing converts specific cytidine residues to uridine in both plastid and mitochondrial transcripts. Previous studies identified pentatricopeptide repeat (PPR) motif-containing proteins as site-specific recognition factors for cytidine targets in RNA sequences. However, the regulatory mechanism underlying RNA editing was largely unknown. Here, we report that protoporphyrinogen IX oxidase 1 (PPO1), an enzyme that catalyzes protoporphyrinogen IX into protoporphyrin IX in the tetrapyrrole biosynthetic pathway, plays an unexpected role in editing multiple sites of plastid RNA transcripts, most of which encode subunits of the NADH dehydrogenase-like complex (NDH), in the reference plant Arabidopsis thaliana. We identified multiple organellar RNA editing factors (MORFs), including MORF2, MORF8, and MORF9, that interact with PPO1. We found that two conserved motifs within the 22-aa region at the N terminus of PPO1 are essential for its interaction with MORFs, its RNA editing function, and subsequently, its effect on NDH activity. However, transgenic plants lacking key domains for the tetrapyrrole biosynthetic activity of PPO1 exhibit normal RNA editing. Furthermore, MORF2 and MORF9 interact with three PPRs or related proteins required for editing of ndhB and ndhD sites. These results reveal that the tetrapyrrole biosynthetic enzyme PPO1 is required for plastid RNA editing, acting as a regulator that promotes the stability of MORF proteins through physical interaction.

• Cytokinin effects on tetrapyrrole biosynthesis and photosynthetic activity in barley seedlings

  2006

  Planta · 157 Zitationen · DOI

• Tomato Fruit Photosynthesis Is Seemingly Unimportant in Primary Metabolism and Ripening But Plays a Considerable Role in Seed Development  

  2011

  PLANT PHYSIOLOGY · 155 Zitationen · DOI

  Fruit of tomato (Solanum lycopersicum), like those from many species, have been characterized to undergo a shift from partially photosynthetic to truly heterotrophic metabolism. While there is plentiful evidence for functional photosynthesis in young tomato fruit, the rates of carbon assimilation rarely exceed those of carbon dioxide release, raising the question of its role in this tissue. Here, we describe the generation and characterization of lines exhibiting a fruit-specific reduction in the expression of glutamate 1-semialdehyde aminotransferase (GSA). Despite the fact that these plants contained less GSA protein and lowered chlorophyll levels and photosynthetic activity, they were characterized by few other differences. Indeed, they displayed almost no differences in fruit size, weight, or ripening capacity and furthermore displayed few alterations in other primary or intermediary metabolites. Although GSA antisense lines were characterized by significant alterations in the expression of genes associated with photosynthesis, as well as with cell wall and amino acid metabolism, these changes were not manifested at the phenotypic level. One striking feature of the antisense plants was their seed phenotype: the transformants displayed a reduced seed set and altered morphology and metabolism at early stages of fruit development, although these differences did not affect the final seed number or fecundity. Taken together, these results suggest that fruit photosynthesis is, at least under ambient conditions, not necessary for fruit energy metabolism or development but is essential for properly timed seed development and therefore may confer an advantage under conditions of stress.

• Control of retrograde signalling by protein import and cytosolic folding stress

  2019

  Nature Plants · 149 Zitationen · DOI

• Regulatory network of tetrapyrrole biosynthesis - studies of intracellular signalling involved in metabolic and developmental control of plastids

  2001

  Planta · 147 Zitationen · DOI

• Expression studies in tetrapyrrole biosynthesis: inverse maxima of magnesium chelatase and ferrochelatase activity during cyclic photoperiods

  1999

  Planta · 141 Zitationen · DOI

• Transiently expressed early light-inducible thylakoid proteins share transmembrane domains with light-harvesting chlorophyll binding proteins

  1989

  Plant Molecular Biology · 140 Zitationen · DOI

• Post-translational control of tetrapyrrole biosynthesis in plants, algae, and cyanobacteria

  2012

  Journal of Experimental Botany · 139 Zitationen · DOI

  The tetrapyrrole biosynthetic pathway provides the vital cofactors and pigments for photoautotrophic growth (chlorophyll), several essential redox reactions in electron transport chains (haem), N- and S-assimilation (sirohaem), and photomorphogenic processes (phytochromobilin). While the biochemistry of the pathway is well understood and almost all genes encoding enzymes of tetrapyrrole biosynthesis have been identified in plants, the post-translational control and organization of the pathway remains to be clarified. Post-translational mechanisms controlling metabolic activities are of particular interest since tetrapyrrole biosynthesis needs adaptation to environmental challenges. This review surveys post-translational mechanisms that have been reported to modulate metabolic activities and organization of the tetrapyrrole biosynthesis pathway.

• Studies on Differential Nuclear Translocation Mechanism and Assembly of the Three Subunits of the Arabidopsis thaliana Transcription Factor NF-Y

  2011

  Molecular Plant · 136 Zitationen · DOI

• Light and dark modulation of chlorophyll biosynthetic genes in response to temperature

  2006

  Planta · 131 Zitationen · DOI

• Crystal structure of glutamate-1-semialdehyde aminomutase: An α ₂ -dimeric vitamin B ₆ -dependent enzyme with asymmetry in structure and active site reactivity

  1997

  Proceedings of the National Academy of Sciences · 131 Zitationen · DOI

  The three-dimensional structure of glutamate-1-semialdehyde aminomutase (EC 5.4.3.8), an alpha2-dimeric enzyme from Synechococcus, has been determined by x-ray crystallography using heavy atom derivative phasing. The structure, refined at 2.4-A resolution to an R-factor of 18.7% and good stereochemistry, explains many of the enzyme's unusual specificity and functional properties. The overall fold is that of aspartate aminotransferase and related B6 enzymes, but it also has specific features. The structure of the complex with gabaculine, a substrate analogue, shows unexpectedly that the substrate binding site involves residues from the N-terminal domain of the molecule, notably Arg-32. Glu-406 is suitably positioned to repel alpha-carboxylic acids, thereby suggesting a basis for the enzyme's reaction specificity. The subunits show asymmetry in cofactor binding and in the mobilities of the residues 153-181. In the unliganded enzyme, one subunit has the cofactor bound as an aldimine of pyridoxal phosphate with Lys-273 and, in this subunit, residues 153-181 are disordered. In the other subunit in which the cofactor is not covalently bound, residues 153-181 are well defined. Consistent with the crystallographically demonstrated asymmetry, a form of the enzyme in which both subunits have pyridoxal phosphate bound to Lys-273 through a Schiff base showed biphasic reduction by borohydride in solution. Analysis of absorption spectra during reduction provided evidence of communication between the subunits. The crystal structure of the reduced form of the enzyme shows that, despite identical cofactor binding in each monomer, the structural asymmetry at residues 153-181 remains.

• Kinetic Studies on the Xanthophyll Cycle in Barley Leaves (Influence of Antenna Size and Relations to Nonphotochemical Chlorophyll Fluorescence Quenching)

  1996

  PLANT PHYSIOLOGY · 131 Zitationen · DOI

  Xanthophyll-cycle kinetics as well as the relationship between the xanthophyll de-epoxidation state and Stern-Volmer type nonphotochemical chlorophyll (Chl) fluorescence quenching (qN) were investigated in barley (Hordeum vulgare L.) leaves comprising a stepwise reduced antenna system. For this purpose plants of the wild type (WT) and the Chl b-less mutant chlorina 3613 were cultivated under either continuous (CL) or intermittent light (IML). Violaxanthin (V) availability varied from about 70% in the WT up to 97 to 98% in the mutant and IML-grown plants. In CL-grown mutant leaves, de-epoxidation rates were strongly accelerated compared to the WT. This is ascribed to a different accessibility of V to the de-epoxidase due to the existence of two V pools: one bound to light-harvesting Chl a/b-binding complexes (LHC) and the other one not bound. Epoxidation rates (k) were decreased with reduction in LHC protein contents: kWT > kmutant >> kIML plants. This supports the idea that the epoxidase activity resides on certain LHC proteins. Irrespective of huge zeaxanthin and antheraxanthin accumulation, the capacity to develop qN was reduced stepwise with antenna size. The qN level obtained in dithiothreitol-treated CL- and IML-grown plants was almost identical with that in untreated IML-grown plants. The findings provide evidence that structural changes within the LHC proteins, mediated by xanthophyll-cycle operation, render the basis for the development of a major proportion of qN.

• Expression and activity of isoenzymes of superoxide dismutase in wheat roots in response to hypoxia and anoxia

  2000

  Plant Cell & Environment · 129 Zitationen · DOI

  ABSTRACT We investigated the effects of hypoxia, anoxia and reaeration on enzymatic activity and expression of superoxide dismutase (SOD) isoforms in wheat roots ( Triticum aestivum L.). Neither hypoxia nor subsequent re‐aeration caused significant changes in SOD isoenzyme pattern compared with aerated controls. However, anoxia led to the appearance of additional activity bands of SOD in native gels resulting in an increase in total activity. Additional isoformic bands remained also apparent in the following recovery period. Re‐aeration following both hypoxia and anoxia resulted in an increased content of hydrogen peroxide in roots. SOD transcript and protein levels were only slightly altered in response to hypoxia. Although SOD mRNA levels were diminished, protein content of different SOD isoforms increased with duration of anoxia. Incubation of roots with cycloheximide revealed that the additional activity bands and higher SOD protein content under anoxia were not due to de novo synthesis. Crude subcellular fractionation experiments implied that the anoxia‐responsive SOD isoforms might be plastid‐associated. We suggest that SOD is a very stable enzyme which, under anoxia, accumulates relative to total protein content and remains active even after protein modification under severe environmental stress conditions.

• Ludwig-Maximilians-Universität München

  SFB/TRR 175/2: Der Chloroplast als zentraler Knotenpunkt der Akklimatisation bei Pflanzen (TP C04)

  university

Name

Prof. Dr. rer. nat. Bernhard Grimm

Titel

Prof. Dr. rer. nat.

Fakultät

Lebenswissenschaftliche Fakultät

Institut

Institut für Biologie

Arbeitsgruppe

Pflanzenphysiologie I

Telefon

+49 30 2093-98332

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