TY  - JOUR
A1  - Mehterov, Nikolay
A1  - Balazadeh, Salma
A1  - Hille, Jacques
A1  - Toneva, Valentina
A1  - Müller-Röber, Bernd
A1  - Gechev, Tsanko S.
T1  - Oxidative stress provokes distinct transcriptional responses in the stress-tolerant atr7 and stress-sensitive loh2 Arabidopsis thaliana mutants as revealed by multi-parallel quantitative real-time PCR analysis of ROS marker and antioxidant genes
JF  - Plant physiology and biochemistry : an official journal of the Federation of European Societies of Plant Physiology
N2  - The Arabidopsis thaliana atr7 mutant is tolerant to oxidative stress induced by paraquat (PQ) or the catalase inhibitor aminotriazole (AT), while its original background loh2 and wild-type plants are sensitive. Both, AT and PQ which stimulate the intracellular formation of H2O2 or superoxide anions, respectively, trigger cell death in loh2 but do not lead to visible damage in atr7. To study gene expression during oxidative stress and ROS-induced programmed cell death, two platforms for multi-parallel quantitative real-time PCR (qRT-PCR) analysis of 217 antioxidant and 180 ROS marker genes were employed. The qRT-PCR analyses revealed AT- and PQ-induced expression of many ROS-responsive genes mainly in loh2, confirming that an oxidative burst plays a role in the activation of the cell death in this mutant. Some of the genes were specifically regulated by either AT or PQ serving as markers for particular types of ROS. Genes significantly induced by both AT and PQ in loh2 included transcription factors (ANAC042/JUB1, ANAC102, DREB19, HSFA2, RRTF1, ZAT10, ZAT12, ethylene-responsive factors), signaling compounds, ferritins, alternative oxidases, and antioxidant enzymes. Many of these genes were upregulated in atr7 compared to loh2 under non-stress conditions at the first time point, indicating that higher basal levels of ROS and higher antioxidant capacity in atr7 are responsible for the enhanced tolerance to oxidative stress and suggesting a possible tolerance against multiple stresses of this mutant.
KW  - Antioxidant genes
KW  - Reactive oxygen species
KW  - Stress tolerance
KW  - Transcription analysis
Y1  - 2012
U6  - https://doi.org/10.1016/j.plaphy.2012.05.024
SN  - 0981-9428
VL  - 59
SP  - 20
EP  - 29
PB  - Elsevier
CY  - Paris
ER  - 
TY  - JOUR
A1  - Benina, Maria
A1  - Obata, Toshihiro
A1  - Mehterov, Nikolay
A1  - Ivanov, Ivan
A1  - Petrov, Veselin
A1  - Toneva, Valentina
A1  - Fernie, Alisdair R.
A1  - Gechev, Tsanko S.
T1  - Comparative metabolic profiling of Haberlea rhodopensis, Thellungiella halophyla, and Arabidopsis thaliana exposed to low temperature
JF  - Frontiers in plant science
N2  - Haberlea rhodopensis is a resurrection species with extreme resistance to drought stress and desiccation but also with ability to withstand low temperatures and freezing stress. In order to identify biochemical strategies which contribute to Haberlea's remarkable stress tolerance, the metabolic reconfiguration of H. rhodopensis during low temperature (4 degrees C) and subsequent return to optimal temperatures (21 degrees C) was investigated and compared with that of the stress tolerant Thellungiella halophyla and the stress sensitive Arabidopsis thaliana. Metabolic analysis by GC-MS revealed intrinsic differences in the metabolite levels of the three species even at 21 degrees C. H. rhodopensis had significantly more raffinose, melibiose, trehalose, rhamnose, myo-inositol, sorbitol, galactinol, erythronate, threonate, 2-oxoglutarate, citrate, and glycerol than the other two species. A. thaliana had the highest levels of putrescine and fumarate, while T halophila had much higher levels of several amino acids, including alanine, asparagine, beta-alanine, histidine, isoleucine, phenylalanine, serine, threonine, and valine. In addition, the three species responded differently to the low temperature treatment and the subsequent recovery, especially with regard to the sugar metabolism. Chilling induced accumulation of maltose in H. rhodopensis and raffinose in A. thaliana but the raffinose levels in low temperature exposed Arabidopsis were still much lower than these in unstressed Haberlea. While all species accumulated sucrose during chilling, that accumulation was transient in H. rhodopensis and A. thaliana but sustained in T halophila after the return to optimal temperature. Thus, Haberlea's metabolome appeared primed for chilling stress but the low temperature acclimation induced additional stress-protective mechanisms. A diverse array of sugars, organic acids, and polyols constitute Haberlea's main metabolic defence mechanisms against chilling, while accumulation of amino acids and amino acid derivatives contribute to the low temperature acclimation in Arabidopsis and Thellungiella. Collectively, these results show inherent differences in the metabolomes under the ambient temperature and the strategies to respond to low temperature in the three species.
KW  - Arabidopsis thaliana
KW  - Haberlea rhodopensis
KW  - low temperature stress
KW  - metabolite profiling
KW  - Thellungiella halophila
Y1  - 2013
U6  - https://doi.org/10.3389/fpls.2013.00499
SN  - 1664-462X
VL  - 4
IS  - 1
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Petrov, Veselin
A1  - Schippers, Jos
A1  - Benina, Maria
A1  - Minkov, Ivan
A1  - Müller-Röber, Bernd
A1  - Gechev, Tsanko S.
T1  - In search for new players of the oxidative stress network by phenotyping an Arabidopsis T-DNA mutant collection on reactive oxygen species-eliciting chemicals
JF  - Plant omics
N2  - The ability of some chemical compounds to cause oxidative stress offers a fast and convenient way to study the responses of plants to reactive oxygen species (ROS). In order to unveil potential novel genetic players of the ROS-regulatory network, a population of similar to 2,000 randomly selected Arabidopsis thaliana T-DNA insertion mutants was screened for ROS sensitivity/resistance by growing seedlings on agar medium supplemented with stress-inducing concentrations of the superoxide-eliciting herbicide methyl viologen or the catalase inhibitor 3-amino-triazole. A semi-robotic setup was used to capture and analyze images of the chemically treated seedlings which helped interpret the screening results by providing quantitative information on seedling area and healthy-to-chlorotic tissue ratios for data verification. A ROS-related phenotype was confirmed in three of the initially selected 33 mutant candidates, which carry T-DNA insertions in genes encoding a Ring/Ubox superfamily protein, ABI5 binding protein 1 (AFP1), previously reported to be involved in ABA signaling, and a protein of unknown function, respectively. In addition, we identified six mutants, most of which have not been described yet, that are related to growth or chloroplast development and show defects in a ROS-independent manner. Thus, semi-automated image capturing and phenotyping applied on publically available T-DNA insertion collections adds a simple means for discovering novel mutants in complex physiological processes and identifying the genes involved.
KW  - growth
KW  - image analysis
KW  - methyl viologen
KW  - LemnaTec
KW  - screening
KW  - superoxide
Y1  - 2013
SN  - 1836-0661
VL  - 6
IS  - 1
SP  - 46
EP  - 54
PB  - Southern Cross Publ.
CY  - Lismore
ER  - 
TY  - JOUR
A1  - Gechev, Tsanko S.
A1  - Benina, Maria
A1  - Obata, Toshihiro
A1  - Tohge, Takayuki
A1  - Neerakkal, Sujeeth
A1  - Minkov, Ivan
A1  - Hille, Jacques
A1  - Temanni, Mohamed-Ramzi
A1  - Marriott, Andrew S.
A1  - Bergström, Ed
A1  - Thomas-Oates, Jane
A1  - Antonio, Carla
A1  - Müller-Röber, Bernd
A1  - Schippers, Jos H. M.
A1  - Fernie, Alisdair R.
A1  - Toneva, Valentina
T1  - Molecular mechanisms of desiccation tolerance in the resurrection glacial relic Haberlea rhodopensis
JF  - Cellular and molecular life sciences
N2  - Haberlea rhodopensis is a resurrection plant with remarkable tolerance to desiccation. Haberlea exposed to drought stress, desiccation, and subsequent rehydration showed no signs of damage or severe oxidative stress compared to untreated control plants. Transcriptome analysis by next-generation sequencing revealed a drought-induced reprogramming, which redirected resources from growth towards cell protection. Repression of photosynthetic and growth-related genes during water deficiency was concomitant with induction of transcription factors (members of the NAC, NF-YA, MADS box, HSF, GRAS, and WRKY families) presumably acting as master switches of the genetic reprogramming, as well as with an upregulation of genes related to sugar metabolism, signaling, and genes encoding early light-inducible (ELIP), late embryogenesis abundant (LEA), and heat shock (HSP) proteins. At the same time, genes encoding other LEA, HSP, and stress protective proteins were constitutively expressed at high levels even in unstressed controls. Genes normally involved in tolerance to salinity, chilling, and pathogens were also highly induced, suggesting a possible cross-tolerance against a number of abiotic and biotic stress factors. A notable percentage of the genes highly regulated in dehydration and subsequent rehydration were novel, with no sequence homology to genes from other plant genomes. Additionally, an extensive antioxidant gene network was identified with several gene families possessing a greater number of antioxidant genes than most other species with sequenced genomes. Two of the transcripts most abundant during all conditions encoded catalases and five more catalases were induced in water-deficient samples. Using the pharmacological inhibitor 3-aminotriazole (AT) to compromise catalase activity resulted in increased sensitivity to desiccation. Metabolome analysis by GC or LC-MS revealed accumulation of sucrose, verbascose, spermidine, and gamma-aminobutyric acid during drought, as well as particular secondary metabolites accumulating during rehydration. This observation, together with the complex antioxidant system and the constitutive expression of stress protective genes suggests that both constitutive and inducible mechanisms contribute to the extreme desiccation tolerance of H. rhodopensis.
KW  - Antioxidant genes
KW  - Catalase
KW  - Desiccation tolerance
KW  - Drought stress
KW  - Metabolome analysis
KW  - Resurrection plants
Y1  - 2013
U6  - https://doi.org/10.1007/s00018-012-1155-6
SN  - 1420-682X
VL  - 70
IS  - 4
SP  - 689
EP  - 709
PB  - Springer
CY  - Basel
ER  - 
TY  - JOUR
A1  - Ivanov, Ivan
A1  - Benina, Maria
A1  - Petrov, Veselin
A1  - Gechev, Tsanko S.
A1  - Toneva, Valentina
T1  - Metabolic responses of gloxinia perennis to dehydration and rehydration
JF  - COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES
N2  - Gloxinia perennis is a species from the family Gesneriaceae with little known physiology, particularly in respect to responses to dehydration. G. perennis survived water deprivation for a month and then quickly recovered upon rehydration. The slow loss of water was in contrast with the quick dehydration of other Gesnerian species - Boea hygrometrica, Ramonda serbica, and Haber lea rhodopensis. Furthermore, a significant difference between older and younger leaves of G. perennis was observed. While the relative water content in the early stages of water deprivation was reduced to 65% in the old leaves, it was not or slightly reduced in the young ones, implying a mechanism that protects specifically the younger leaves from dehydration. Water deprivation induced accumulation of gama-aminobutyric acid and sugars like sucrose and raffinose, but decreased the levels of amino acids such as glycine, leucine, and isoleucine. The levels of these amino acids recovered after rehydration and in some cases like glycine and isoleucine were even higher in rehydrated leaves compared with unstressed controls. We conclude that G.perennis can survive prolonged drought stress but its responses to dehydration are different from the resurrection species from Gesneriaceae. All this makes G. perennis a good model that can be used for comparative genomics and metabolomics of Gesneriads exposed to desiccation.
KW  - Gloxinia perennis
KW  - drought stress
KW  - metabolome analysis
Y1  - 2014
SN  - 1310-1331
VL  - 67
IS  - 12
SP  - 1657
EP  - 1662
PB  - Publ. House of the Bulgarian Acad. of Sciences
CY  - Sofia
ER  - 
TY  - JOUR
A1  - Gechev, Tsanko S.
A1  - Hille, Jacques
A1  - Woerdenbag, Herman J.
A1  - Benina, Maria
A1  - Mehterov, Nikolay
A1  - Toneva, Valentina
A1  - Fernie, Alisdair R.
A1  - Müller-Röber, Bernd
T1  - Natural products from resurrection plants: Potential for medical applications
JF  - Biotechnology advances : an international review journal ; research reviews and patent abstracts
N2  - Resurrection species are a group of land plants that can tolerate extreme desiccation of their vegetative tissues during harsh drought stress, and still quickly often within hours regain normal physiological and metabolic functions following rehydration. At the molecular level, this desiccation tolerance is attributed to basal cellular mechanisms including the constitutive expression of stress-associated genes and high levels of protective metabolites present already in the absence of stress, as well as to transcriptome and metabolome reconfigurations rapidly occurring during the initial phases of drought stress. Parts of this response are conferred by unique metabolites, including a diverse array of sugars, phenolic compounds, and polyols, some of which accumulate to high concentrations within the plant cell. In addition to drought stress, these metabolites are proposed to contribute to the protection against other abiotic stresses and to an increased oxidative stress tolerance. Recently, extracts of resurrection species and particular secondary metabolites therein were reported to display biological activities of importance to medicine, with e.g. antibacterial, anticancer, antifungal, and antiviral activities, rendering them possible candidates for the development of novel drug substances as well as for cosmetics. Herein, we provide an overview of the metabolite composition of resurrection species, summarize the latest reports related to the use of natural products from resurrection plants, and outline their potential for medical applications. (C) 2014 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).
KW  - Antibacterial
KW  - Anticancer
KW  - Antifungal
KW  - Antiviral
KW  - Natural product
KW  - Resurrection plant
KW  - Secondary metabolite
KW  - Synthetic biology
Y1  - 2014
U6  - https://doi.org/10.1016/j.biotechadv.2014.03.005
SN  - 0734-9750
SN  - 1873-1899
VL  - 32
IS  - 6
SP  - 1091
EP  - 1101
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
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
JF  - Frontiers in plant science
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.
KW  - abiotic stress
KW  - programmed cell death
KW  - reactive oxygen species
KW  - signal transduction
KW  - stress adaptation
Y1  - 2015
U6  - https://doi.org/10.3389/fpls.2015.00069
SN  - 1664-462X
VL  - 6
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Benina, Maria
A1  - Ribeiro, Dimas Mendes
A1  - Gechev, Tsanko S.
A1  - Müller-Röber, Bernd
A1  - Schippers, Jos H. M.
T1  - A cell type-specific view on the translation of mRNAs from ROS-responsive genes upon paraquat treatment of Arabidopsis thaliana leaves
JF  - Plant, cell & environment : cell physiology, whole-plant physiology, community physiology
N2  - Oxidative stress causes dramatic changes in the expression levels of many genes. The formation of a functional protein through successful mRNA translation is central to a coordinated cellular response. To what extent the response towards reactive oxygen species (ROS) is regulated at the translational level is poorly understood. Here we analysed leaf- and tissue-specific translatomes using a set of transgenic Arabidopsis thaliana lines expressing a FLAG-tagged ribosomal protein to immunopurify polysome-bound mRNAs before and after oxidative stress. We determined transcript levels of 171 ROS-responsive genes upon paraquat treatment, which causes formation of superoxide radicals, at the whole-organ level. Furthermore, the translation of mRNAs was determined for five cell types: mesophyll, bundle sheath, phloem companion, epidermal and guard cells. Mesophyll and bundle sheath cells showed the strongest response to paraquat treatment. Interestingly, several ROS-responsive transcription factors displayed cell type-specific translation patterns, while others were translated in all cell types. In part, cell type-specific translation could be explained by the length of the 5-untranslated region (5-UTR) and the presence of upstream open reading frames (uORFs). Our analysis reveals insights into the translational regulation of ROS-responsive genes, which is important to understanding cell-specific responses and functions during oxidative stress.
 The study illustrates the response of different Arabidopsis thaliana leaf cells and tissues to oxidative stress at the translational level, an aspect of reactive oxygen species (ROS) biology that has been little studied in the past. Our data reveal insights into how translational regulation of ROS-responsive genes is fine-tuned at the cellular level, a phenomenon contributing to the integrated physiological response of leaves to stresses involving changes in ROS levels.
KW  - Arabidopsis
KW  - gene regulation
KW  - oxidative stress
KW  - tissue-specific
KW  - translation
Y1  - 2015
U6  - https://doi.org/10.1111/pce.12355
SN  - 0140-7791
SN  - 1365-3040
VL  - 38
IS  - 2
SP  - 349
EP  - 363
PB  - Wiley-Blackwell
CY  - Hoboken
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  - GEN
A1  - Durgud, Meriem
A1  - Gupta, Saurabh
A1  - Ivanov, Ivan
A1  - Omidbakhshfard, Mohammad Amin
A1  - Benina, Maria
A1  - Alseekh, Saleh
A1  - Staykov, Nikola
A1  - Hauenstein, Mareike
A1  - Dijkwel, Paul P.
A1  - Hortensteiner, Stefan
A1  - Toneva, Valentina
A1  - Brotman, Yariv
A1  - Fernie, Alisdair R.
A1  - Müller-Röber, Bernd
A1  - Gechev, Tsanko S.
T1  - Molecular mechanisms preventing senescence in response to prolonged darkness in a desiccation-tolerant plant
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - The desiccation-tolerant plant Haberlea rhodopensis can withstand months of darkness without any visible senescence. Here, we investigated the molecular mechanisms of this adaptation to prolonged (30 d) darkness and subsequent return to light. H. rhodopensis plants remained green and viable throughout the dark treatment. Transcriptomic analysis revealed that darkness regulated several transcription factor (TF) genes. Stress-and autophagy-related TFs such as ERF8, HSFA2b, RD26, TGA1, and WRKY33 were up-regulated, while chloroplast-and flowering-related TFs such as ATH1, COL2, COL4, RL1, and PTAC7 were repressed. PHYTOCHROME INTERACTING FACTOR4, a negative regulator of photomorphogenesis and promoter of senescence, also was down-regulated. In response to darkness, most of the photosynthesis-and photorespiratory-related genes were strongly down-regulated, while genes related to autophagy were up-regulated. This occurred concomitant with the induction of SUCROSE NON-FERMENTING1-RELATED PROTEIN KINASES (SnRK1) signaling pathway genes, which regulate responses to stress-induced starvation and autophagy. Most of the genes associated with chlorophyll catabolism, which are induced by darkness in dark-senescing species, were either unregulated (PHEOPHORBIDE A OXYGENASE, PAO; RED CHLOROPHYLL CATABOLITE REDUCTASE, RCCR) or repressed (STAY GREEN-LIKE, PHEOPHYTINASE, and NON-YELLOW COLORING1). Metabolite profiling revealed increases in the levels of many amino acids in darkness, suggesting increased protein degradation. In darkness, levels of the chloroplastic lipids digalactosyldiacylglycerol, monogalactosyldiacylglycerol, phosphatidylglycerol, and sulfoquinovosyldiacylglycerol decreased, while those of storage triacylglycerols increased, suggesting degradation of chloroplast membrane lipids and their conversion to triacylglycerols for use as energy and carbon sources. Collectively, these data show a coordinated response to darkness, including repression of photosynthetic, photorespiratory, flowering, and chlorophyll catabolic genes, induction of autophagy and SnRK1 pathways, and metabolic reconfigurations that enable survival under prolonged darkness.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 778 
KW  - beta-oxidation
KW  - craterostigma-plantagineum
KW  - photosynthetic apparatus
KW  - transcription factors
KW  - lipid-metabolism
KW  - leaf senescence
KW  - fatty-acid
KW  - arabidopsis
KW  - chlorophyll
KW  - stress
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-437588
IS  - 778
SP  - 1319
EP  - 1338
ER  -