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Publikationen - Molekulare Signalverarbeitung

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Publikation

Wasternack, C.; Hause, B. Jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in <span>Annals of Botany</span> Annals of Botany 111, 1021-1058, (2013) DOI: 10.1093/aob/mct067

Background: Jasmonates are important regulators in plant responses to biotic and abiotic stresses as well as indevelopment. Synthesized from lipid-constituents, the initially formed jasmonic acid is converted to differentmetabolites including the conjugate with isoleucine. Important new components of jasmonate signalling includingits receptor were identified, providing deeper insight into the role of jasmonate signalling pathways in stressresponses and development.Scope: The present review is an update of the review on jasmonates published in this journal in 2007. New dataof the last five years are described with emphasis on metabolites of jasmonates, on jasmonate perception andsignalling, on cross-talk to other plant hormones and on jasmonate signalling in response to herbivores and pathogens,in symbiotic interactions, in flower development, in root growth and in light perception.Conclusions: The last few years have seen breakthroughs in the identification of JASMONATE ZIM DOMAIN(JAZ) proteins and their interactors such as transcription factors and co-repressors, and the crystallization of thejasmonate receptor as well as of the enzyme conjugating jasmonate to amino acids. Now, the complex nature ofnetworks of jasmonate signalling in stress responses and development including hormone cross-talk can beaddressed.
Publikation

Kopycki, J.; Wieduwild, E.; Kohlschmidt, J.; Brandt, W.; Stepanova, A.N.; Alonso, J.M.; Pedras, M.S.; Abel, S.; Grubb, C.D. Kinetic analysis of Arabidopsis glucosyltransferase UGT74B1 illustrates a general mechanism by which enzymes can escape product inhibition Biochem J 450, 37-46, (2013) DOI: 10.1042/BJ20121403

Plant genomes encode numerous small molecule glycosyltransferases which modulate the solubility, activity, immunogenicity and/or reactivity of hormones, xenobiotics and natural products. The products of these enzymes can accumulate to very high concentrations, yet somehow avoid inhibiting their own biosynthesis. Glucosyltransferase UGT74B1 (UDP-glycosyltransferase 74B1) catalyses the penultimate step in the core biosynthetic pathway of glucosinolates, a group of natural products with important functions in plant defence against pests and pathogens. We found that mutation of the highly conserved Ser284 to leucine [wei9-1 (weak ethylene insensitive)] caused only very mild morphological and metabolic phenotypes, in dramatic contrast with knockout mutants, indicating that steady state glucosinolate levels are actively regulated even in unchallenged plants. Analysis of the effects of the mutation via a structural modelling approach indicated that the affected serine interacts directly with UDP-glucose, but also predicted alterations in acceptor substrate affinity and the kcat value, sparking an interest in the kinetic behaviour of the wild-type enzyme. Initial velocity and inhibition studies revealed that UGT74B1 is not inhibited by its glycoside product. Together with the effects of the missense mutation, these findings are most consistent with a partial rapid equilibrium ordered mechanism. This model explains the lack of product inhibition observed both in vitro and in vivo, illustrating a general mechanism whereby enzymes can continue to function even at very high product/precursor ratios.
Publikation

Dekkers, B.J.W.; Pearce, S.; van Bolderen-Veldkamp, R.P.; Marshall, A.; Widera, P.; Gilbert, J.; Drost, H.-G.; Basseli, G.W.; Müller, K.; King, J.R.; Wood, A.T.A.; Grosse, I.; Quint, M.; Krasnogor, N.; Leubner-Metzger, G.; Holdsworth, M.J. & Bentsink, L. Transcriptional Dynamics of Two Seed Compartments with Opposing Roles in Arabidopsis Seed Germination Plant Physiol 163, 205-215, (2013) DOI: 10.1104/pp.113.223511

Seed germination is a critical stage in the plant life cycle and the first step toward successful plant establishment. Therefore, understandinggermination is of important ecological and agronomical relevance. Previous research revealed that different seed compartments (testa,endosperm, and embryo) control germination, but little is known about the underlying spatial and temporal transcriptome changes thatlead to seed germination. We analyzed genome-wide expression in germinating Arabidopsis (Arabidopsis thaliana) seedswith both temporaland spatial detail and provide Web-accessible visualizations of the data reported (vseed.nottingham.ac.uk). We show the potential of this highresolutiondata set for the construction ofmeaningful coexpression networks, which provide insight into the genetic control of germination.The data set reveals two transcriptional phases during germination that are separated by testa rupture. The first phase is marked by largetranscriptome changes as the seed switches from a dry, quiescent state to a hydrated and active state. At the end of this first transcriptionalphase, the number of differentially expressed genes between consecutive time points drops. This increases again at testa rupture, the start ofthe second transcriptional phase. Transcriptome data indicate a role for mechano-induced signaling at this stage and subsequently highlightthe fates of the endosperm and radicle: senescence and growth, respectively. Finally, using a phylotranscriptomic approach, we show thatexpression levels of evolutionarily young genes drop during the first transcriptional phase and increase during the second phase.Evolutionarily old genes show an opposite pattern, suggesting a more conserved transcriptome prior to the completion of germination.
Publikation

Feussner, I.; Hause, B.; Nellen, A.; Wasternack, C.; Kindl, H. Lipid-body lipoxygenase is expressed in cotyledons during germination prior to other lipoxygenase forms Planta 198, 288-293, (1996) DOI: 10.1007/BF00206255

Lipid bodies are degraded during germination. Whereas some proteins, e.g. oleosins, are synthesized during the formation of lipid bodies of maturating seeds, a new set of proteins, including a specific form of lipoxygenase (LOX; EC 1.13.11.12), is detectable in lipid bodies during the stage of fat degradation in seed germination. In cotyledons of cucumber (Cucumis sativus L.) seedlings at day 4 of germination, the most conspicuous staining with anti-LOX antibodies was observed in the cytosol. At very early stages of germination, however, the LOX form present in large amounts and synthesized preferentially was the lipid-body LOX. This was demonstrated by immunocytochemical staining of cotyledons from 1-h and 24-h-old seedlings: the immunodecoration of sections of 24-h-old seedlings with anti-LOX antiserum showed label exclusively correlated with lipid bodies of around 3 μm in diameter. In accordance, the profile of LOX protein isolated from lipid bodies during various stages of germination showed a maximum at day 1. By measuring biosynthesis of the protein in vivo we demonstrated that the highest rates of synthesis of lipid-body LOX occurred at day 1 of germination. The early and selective appearance of a LOX form associated with lipid bodies at this stage of development is discussed.
Publikation

Abdala, G.; Castro, G.; Guinazu, M.; Tizio, R.; Miersch, O. Occurrence of jasmonic acid in organs of <EM>Solanum tuberosum</EM> L. c.v. Spunta and its effect on tuberization Plant Growth Reg. 19, 139-143, (1996)

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Publikation

Herde, O.; Atzorn, R.; Fisahn, J.; Wasternack, C.; Willmitzer, L.; Peña-Cortés, H. Localized wounding by heat initiates the accumulation of proteinase inhibitor II in abscisic acid-deficient plants by triggering jasmonic acid biosynthesis Plant Physiol. 112, 853-860, (1996)

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Publikation

Peña-Cortés, H.; Prat, S.; Atzorn, R.; Wasternack, C.; Willmitzer, L. Pin2 gene expression in potato and tomato detached leaves from ABA-deficient potato and tomato plants upon systemin treatment Planta 198, 447-451, (1996)

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Publikation

Wasternack, C.; Atzorn, R.; Pena-Cortes, H.; Parthier, B. Alteration of gene expression by jasmonate and ABA in tobacco and tomato J. Plant Physiol. 147, 503-510, (1996)

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Publikation

Feussner, K.; Guranowski, A.; Kostka, S.; Wasternack, C. Diadenosine 5'5'''-P1,P4-tetraphosphate (Ap4A) hydrolase from tomato (<EM>Lycopersicon esculentum</EM> cv. Lukullus) - Purification, Biochemical properties and behaviour during stress Z. Naturforsch. 51c, 477-486, (1996)

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Publikation

O'Donnell, P.J.; Calvert, C.; Atzorn, R.; Wasternack, C.; Leyser, H.M.O.; Bowles, D.J. Ethylene as a signal mediating the wound response of tomato plants Science 274, 1914-1917, (1996)

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