TY - GEN A1 - Knox-Brown, Patrick A1 - Rindfleisch, Tobias A1 - Günther, Anne A1 - Balow, Kim A1 - Bremer, Anne A1 - Walther, Dirk A1 - Miettinen, Markus S. A1 - Hincha, Dirk K. A1 - Thalhammer, Anja T1 - Similar Yet Different BT - Structural and Functional Diversity among Arabidopsis thaliana LEA_4 Proteins T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The importance of intrinsically disordered late embryogenesis abundant (LEA) proteins in the tolerance to abiotic stresses involving cellular dehydration is undisputed. While structural transitions of LEA proteins in response to changes in water availability are commonly observed and several molecular functions have been suggested, a systematic, comprehensive and comparative study of possible underlying sequence-structure-function relationships is still lacking. We performed molecular dynamics (MD) simulations as well as spectroscopic and light scattering experiments to characterize six members of two distinct, lowly homologous clades of LEA_4 family proteins from Arabidopsis thaliana. We compared structural and functional characteristics to elucidate to what degree structure and function are encoded in LEA protein sequences and complemented these findings with physicochemical properties identified in a systematic bioinformatics study of the entire Arabidopsis thaliana LEA_4 family. Our results demonstrate that although the six experimentally characterized LEA_4 proteins have similar structural and functional characteristics, differences concerning their folding propensity and membrane stabilization capacity during a freeze/thaw cycle are obvious. These differences cannot be easily attributed to sequence conservation, simple physicochemical characteristics or the abundance of sequence motifs. Moreover, the folding propensity does not appear to be correlated with membrane stabilization capacity. Therefore, the refinement of LEA_4 structural and functional properties is likely encoded in specific patterns of their physicochemical characteristics. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 901 KW - IDP KW - LEA protein KW - abiotic stress KW - dehydration KW - conformational rearrangement KW - membrane stabilization KW - sequence-structure-function relationship Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469419 SN - 1866-8372 IS - 901 ER - TY - GEN A1 - Petrov, Veselin A1 - Hille, Jacques A1 - Müller-Röber, Bernd A1 - Gechev, Tsanko S. T1 - ROS-mediated abiotic stress-induced programmed cell death in plants T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - During the course of their ontogenesis plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms have developed complex strategies to withstand them. When the intensity of a detrimental factor is high, one of the defense programs employed by plants is the induction of programmed cell death (PCD). This is an active, genetically controlled process which is initiated to isolate and remove damaged tissues thereby ensuring the survival of the organism. The mechanism of PCD induction usually includes an increase in the levels of reactive oxygen species (ROS) which are utilized as mediators of the stress signal. Abiotic stress-induced PCD is not only a process of fundamental biological importance, but also of considerable interest to agricultural practice as it has the potential to significantly influence crop yield. Therefore, numerous scientific enterprises have focused on elucidating the mechanisms leading to and controlling PCD in response to adverse conditions in plants. This knowledge may help develop novel strategies to obtain more resilient crop varieties with improved tolerance and enhanced productivity. The aim of the present review is to summarize the recent advances in research on ROS-induced PCD related to abiotic stress and the role of the organelles in the process. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 425 KW - abiotic stress KW - programmed cell death KW - reactive oxygen species KW - signal transduction KW - stress adaptation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-406481 IS - 425 ER - TY - THES A1 - Oberkofler, Vicky T1 - Molecular basis of HS memory in Arabidopsis thaliana T1 - Die molekulare Basis des Hitzestress-Gedächtnisses in Arabidopsis thaliana N2 - Plants can be primed to survive the exposure to a severe heat stress (HS) by prior exposure to a mild HS. The information about the priming stimulus is maintained by the plant for several days. This maintenance of acquired thermotolerance, or HS memory, is genetically separable from the acquisition of thermotolerance itself and several specific regulatory factors have been identified in recent years. On the molecular level, HS memory correlates with two types of transcriptional memory, type I and type II, that characterize a partially overlapping subset of HS-inducible genes. Type I transcriptional memory or sustained induction refers to the sustained transcriptional induction above non-stressed expression levels of a gene for a prolonged time period after the end of the stress exposure. Type II transcriptional memory refers to an altered transcriptional response of a gene after repeated exposure to a stress of similar duration and intensity. In particular, enhanced re-induction refers to a transcriptional pattern in which a gene is induced to a significantly higher degree after the second stress exposure than after the first. This thesis describes the functional characterization of a novel positive transcriptional regulator of type I transcriptional memory, the heat shock transcription factor HSFA3, and compares it to HSFA2, a known positive regulator of type I and type II transcriptional memory. It investigates type I transcriptional memory and its dependence on HSFA2 and HSFA3 for the first time on a genome-wide level, and gives insight on the formation of heteromeric HSF complexes in response to HS. This thesis confirms the tight correlation between transcriptional memory and H3K4 hyper-methylation, reported here in a case study that aimed to reduce H3K4 hyper-methylation of the type II transcriptional memory gene APX2 by CRISPR/dCas9-mediated epigenome editing. Finally, this thesis gives insight into the requirements for a heat shock transcription factor to function as a positive regulator of transcriptional memory, both in terms of its expression profile and protein abundance after HS and the contribution of individual functional domains. In summary, this thesis contributes to a more detailed understanding of the molecular processes underlying transcriptional memory and therefore HS memory, in Arabidopsis thaliana. N2 - Pflanzen können darauf vorbereitet werden, einen schweren Hitzestress (HS) zu überleben, indem sie zuvor einem leichten HS ausgesetzt werden. Die Information über den Priming-Stimulus wird von der Pflanze mehrere Tage lang aufrechterhalten. Diese Aufrechterhaltung der erworbenen Thermotoleranz, das so genannte HS-Gedächtnis, ist genetisch vom Erwerb der Thermotoleranz selbst trennbar, und in den letzten Jahren wurden mehrere spezifische Regulierungsfaktoren identifiziert. Auf molekularer Ebene korreliert das HS-Gedächtnis mit zwei Arten von Transkriptionsgedächtnis, Typ I und Typ II, die eine sich teilweise überschneidende Untergruppe von HS-induzierbaren Genen charakterisieren. Das Transkriptionsgedächtnis vom Typ I oder die anhaltende Induktion bezieht sich auf die anhaltende Transkriptionsinduktion eines Gens über das Niveau der Expression im ungestressten Zustand hinaus über einen längeren Zeitraum nach dem Ende der Stressbelastung. Das Transkriptionsgedächtnis des Typs II bezieht sich auf eine veränderte Transkriptionsreaktion eines Gens nach wiederholter Exposition gegenüber einem Hitzestress von ähnlicher Dauer und Intensität. Insbesondere bezieht sich dabei die verstärkte Re-Induktion auf ein Transkriptionsmuster, bei dem ein Gen nach der zweiten Stressexposition in deutlich höherem Maße induziert wird als nach der ersten. Diese Arbeit beschreibt die funktionelle Charakterisierung eines neuartigen positiven Transkriptionsregulators des Typ-I-Transkriptionsgedächtnisses, des Hitzeschock-Transkriptionsfaktors HSFA3, und vergleicht ihn mit HSFA2, einem bekannten positiven Regulator des Typ-I- und Typ-II-Transkriptionsgedächtnisses. Die Arbeit untersucht das Typ-I-Transkriptionsgedächtnis und seine Abhängigkeit von HSFA2 und HSFA3 zum ersten Mal auf genomweiter Ebene und gibt Einblick in die Bildung heteromerer HSF-Komplexe als Reaktion auf HS. Diese Arbeit bestätigt den engen Zusammenhang zwischen transkriptionellem Gedächtnis und H3K4-Hypermethylierung, über den hier in einer Fallstudie berichtet wird, die darauf abzielt, die H3K4-Hypermethylierung des Typ-II-Transkriptionsgedächtnisgens APX2 durch CRISPR/dCas9-vermitteltes Epigenom-Editing zu reduzieren. Schließlich gibt diese Arbeit einen Einblick in die Anforderungen, die ein Hitzeschock-Transkriptionsfaktor erfüllen muss, damit er als positiver Regulator des Transkriptionsgedächtnisses fungieren kann, und zwar sowohl in Bezug auf sein Expressionsprofil und seine Proteinabundanz nach HS als auch in Bezug auf den Beitrag seiner einzelnen funktionellen Domänen. Zusammenfassend trägt diese Arbeit zu einem genaueren Verständnis der molekularen Prozesse bei, die dem Transkriptionsgedächtnis und damit dem HS-Gedächtnis in Arabidopsis thaliana zugrunde liegen. KW - Arabidopsis thaliana KW - abiotic stress KW - heat stress memory KW - transcription factors KW - HSF KW - epigenome editing KW - histone methylation KW - H3K4me KW - Arabidopsis thaliana KW - H3K4me KW - Hitzeschock-Transkriptionsfaktor KW - abiotischer Stress KW - Epigenom Editierung KW - Hitzestress-Gedächtnis KW - Histon Methylierung KW - Transkriptionsfaktoren Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-569544 ER - TY - GEN A1 - Gupta, Saurabh A1 - Dong, Yanni A1 - Dijkwel, Paul P. A1 - Müller-Röber, Bernd A1 - Gechev, Tsanko S. T1 - Genome-Wide Analysis of ROS Antioxidant Genes in Resurrection Species Suggest an Involvement of Distinct ROS Detoxification Systems during Desiccation T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Abiotic stress is one of the major threats to plant crop yield and productivity. When plants are exposed to stress, production of reactive oxygen species (ROS) increases, which could lead to extensive cellular damage and hence crop loss. During evolution, plants have acquired antioxidant defense systems which can not only detoxify ROS but also adjust ROS levels required for proper cell signaling. Ascorbate peroxidase (APX), glutathione peroxidase (GPX), catalase (CAT) and superoxide dismutase (SOD) are crucial enzymes involved in ROS detoxification. In this study, 40 putative APX, 28 GPX, 16 CAT, and 41 SOD genes were identified from genomes of the resurrection species Boea hygrometrica, Selaginella lepidophylla, Xerophyta viscosa, and Oropetium thomaeum, and the mesophile Selaginella moellendorffi. Phylogenetic analyses classified the APX, GPX, and SOD proteins into five clades each, and CAT proteins into three clades. Using co-expression network analysis, various regulatory modules were discovered, mainly involving glutathione, that likely work together to maintain ROS homeostasis upon desiccation stress in resurrection species. These regulatory modules also support the existence of species-specific ROS detoxification systems. The results suggest molecular pathways that regulate ROS in resurrection species and the role of APX, GPX, CAT and SOD genes in resurrection species during stress. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 763 KW - abiotic stress KW - desiccation KW - resurrection plants KW - ROS KW - ascorbate peroxidase KW - glutathione peroxidase KW - catalase KW - superoxide dismutase Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-437299 SN - 1866-8372 IS - 763 ER - TY - GEN A1 - Bäurle, Isabel A1 - Trindade, Inês T1 - Chromatin regulation of somatic abiotic stress memory T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - In nature, plants are often subjected to periods of recurrent environmental stress that can strongly affect their development and productivity. To cope with these conditions, plants can remember a previous stress, which allows them to respond more efficiently to a subsequent stress, a phenomenon known as priming. This ability can be maintained at the somatic level for a few days or weeks after the stress is perceived, suggesting that plants can store information of a past stress during this recovery phase. While the immediate responses to a single stress event have been extensively studied, knowledge on priming effects and how stress memory is stored is still scarce. At the molecular level, memory of a past condition often involves changes in chromatin structure and organization, which may be maintained independently from transcription. In this review, we will summarize the most recent developments in the field and discuss how different levels of chromatin regulation contribute to priming and plant abiotic stress memory. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1408 KW - abiotic stress KW - chromatin regulation KW - heat stress memory KW - histone modifications, priming KW - transcriptional memory KW - vernalization Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-516668 SN - 1866-8372 IS - 17 ER -