@article{BeninaObataMehterovetal.2013, author = {Benina, Maria and Obata, Toshihiro and Mehterov, Nikolay and Ivanov, Ivan and Petrov, Veselin and Toneva, Valentina and Fernie, Alisdair R. and Gechev, Tsanko S.}, title = {Comparative metabolic profiling of Haberlea rhodopensis, Thellungiella halophyla, and Arabidopsis thaliana exposed to low temperature}, series = {Frontiers in plant science}, volume = {4}, journal = {Frontiers in plant science}, number = {1}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2013.00499}, pages = {11}, year = {2013}, abstract = {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.}, language = {en} } @misc{BeninaRibeiroGechevetal.2015, author = {Benina, Maria and Ribeiro, Dimas Mendes and Gechev, Tsanko S. and M{\"u}ller-R{\"o}ber, Bernd and Schippers, Jos H. M.}, title = {A cell type-specific view on the translation of mRNAs from ROS-responsive genes upon paraquat treatment of Arabidopsis thaliana leaves}, series = {Plant, cell \& environment : cell physiology, whole-plant physiology, community physiology}, volume = {38}, journal = {Plant, cell \& environment : cell physiology, whole-plant physiology, community physiology}, number = {2}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0140-7791}, doi = {10.1111/pce.12355}, pages = {349 -- 363}, year = {2015}, abstract = {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.}, language = {en} } @article{DongGuptaSieversetal.2019, author = {Dong, Yanni and Gupta, Saurabh and Sievers, Rixta and Wargent, Jason J. and Wheeler, David and Putterill, Joanna and Macknight, Richard and Gechev, Tsanko S. and M{\"u}ller-R{\"o}ber, Bernd and Dijkwel, Paul P.}, title = {Genome draft of the Arabidopsis relative Pachycladon cheesemanii reveals environment}, series = {BMC genomics}, volume = {20}, journal = {BMC genomics}, number = {1}, publisher = {BMC}, address = {London}, issn = {1471-2164}, doi = {10.1186/s12864-019-6084-4}, pages = {14}, year = {2019}, abstract = {BackgroundPachycladon cheesemanii is a close relative of Arabidopsis thaliana and is an allotetraploid perennial herb which is widespread in the South Island of New Zealand. It grows at altitudes of up to 1000m where it is subject to relatively high levels of ultraviolet (UV)-B radiation. To gain first insights into how Pachycladon copes with UV-B stress, we sequenced its genome and compared the UV-B tolerance of two Pachycladon accessions with those of two A. thaliana accessions from different altitudes.ResultsA high-quality draft genome of P. cheesemanii was assembled with a high percentage of conserved single-copy plant orthologs. Synteny analysis with genomes from other species of the Brassicaceae family found a close phylogenetic relationship of P. cheesemanii with Boechera stricta from Brassicaceae lineage I. While UV-B radiation caused a greater growth reduction in the A. thaliana accessions than in the P. cheesemanii accessions, growth was not reduced in one P. cheesemanii accession. The homologues of A. thaliana UV-B radiation response genes were duplicated in P. cheesemanii, and an expression analysis of those genes indicated that the tolerance mechanism in P. cheesemanii appears to differ from that in A. thaliana.ConclusionAlthough the P. cheesemanii genome shows close similarity with that of A. thaliana, it appears to have evolved novel strategies allowing the plant to tolerate relatively high UV-B radiation.}, language = {en} } @misc{DurgudGuptaIvanovetal.2018, author = {Durgud, Meriem and Gupta, Saurabh and Ivanov, Ivan and Omidbakhshfard, Mohammad Amin and Benina, Maria and Alseekh, Saleh and Staykov, Nikola and Hauenstein, Mareike and Dijkwel, Paul P. and Hortensteiner, Stefan and Toneva, Valentina and Brotman, Yariv and Fernie, Alisdair R. and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {Molecular mechanisms preventing senescence in response to prolonged darkness in a desiccation-tolerant plant}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {778}, doi = {10.25932/publishup-43758}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-437588}, pages = {1319 -- 1338}, year = {2018}, abstract = {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.}, language = {en} } @article{DurgudGuptaIvanovetal.2018, author = {Durgud, Meriem and Gupta, Saurabh and Ivanov, Ivan and Omidbakhshfard, Mohammad Amin and Benina, Maria and Alseekh, Saleh and Staykov, Nikola and Hauenstein, Mareike and Dijkwel, Paul P. and Hortensteiner, Stefan and Toneva, Valentina and Brotman, Yariv and Fernie, Alisdair R. and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {Molecular Mechanisms Preventing Senescence in Response to Prolonged Darkness in a Desiccation-Tolerant Plant}, series = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, volume = {177}, journal = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, number = {3}, publisher = {American Society of Plant Physiologists}, address = {Rockville}, issn = {0032-0889}, doi = {10.1104/pp.18.00055}, pages = {1319 -- 1338}, year = {2018}, abstract = {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.}, language = {en} } @article{FaisalGechevMuellerRoeberetal.2020, author = {Faisal, Muhammad B. and Gechev, Tsanko S. and M{\"u}ller-R{\"o}ber, Bernd and Dijkwel, Paul P.}, title = {Putative alternative translation start site-encoding nucleotides of CPR5 regulate growth and resistance}, series = {BMC plant biology}, volume = {20}, journal = {BMC plant biology}, number = {1}, publisher = {BMC}, address = {London}, issn = {1471-2229}, doi = {10.1186/s12870-020-02485-2}, pages = {10}, year = {2020}, abstract = {Background The Arabidopsis CONSTITUTIVE EXPRESSER of PATHOGENESIS-RELATED GENES 5 (CPR5) has recently been shown to play a role in gating as part of the nuclear pore complex (NPC). Mutations in CPR5 cause multiple defects, including aberrant trichomes, reduced ploidy levels, reduced growth and enhanced resistance to bacterial and fungal pathogens. The pleiotropic nature of cpr5 mutations implicates that the CPR5 protein affects multiple pathways. However, little is known about the structural features that allow CPR5 to affect the different pathways. Results Our in silico studies suggest that in addition to three clusters of putative nuclear localization signals and four or five transmembrane domains, CPR5 contains two putative alternative translation start sites. To test the role of the methionine-encoding nucleotides implicated in those sites, metCPR5 cDNAs, in which the relevant nucleotides were changed to encode glutamine, were fused to the CPR5 native promoter and the constructs transformed to cpr5-2 plants to complement cpr5-compromised phenotypes. The control and metCPR5 constructs were able to complement all cpr5 phenotypes, although the extent of complementation depended on the specific complementing plant lines. Remarkably, plants transformed with metCPR5 constructs showed larger leaves and displayed reduced resistance when challenged to Pseudomonas syringae pv Pst DC3000, as compared to control plants. Thus, the methionine-encoding nucleotides regulate growth and resistance. We propose that structural features of the CPR5 N-terminus are implicated in selective gating of proteins involved in regulating the balance between growth and resistance. Conclusion Plants need to carefully balance the amount of resources used for growth and resistance. The Arabidopsis CPR5 protein regulates plant growth and immunity. Here we show that N-terminal features of CPR5 are involved in the regulation of the balance between growth and resistance. These findings may benefit efforts to improve plant yield, while maintaining optimal levels of disease resistance.}, language = {en} } @article{GechevBeninaObataetal.2013, author = {Gechev, Tsanko S. and Benina, Maria and Obata, Toshihiro and Tohge, Takayuki and Neerakkal, Sujeeth and Minkov, Ivan and Hille, Jacques and Temanni, Mohamed-Ramzi and Marriott, Andrew S. and Bergstr{\"o}m, Ed and Thomas-Oates, Jane and Antonio, Carla and M{\"u}ller-R{\"o}ber, Bernd and Schippers, Jos H. M. and Fernie, Alisdair R. and Toneva, Valentina}, title = {Molecular mechanisms of desiccation tolerance in the resurrection glacial relic Haberlea rhodopensis}, series = {Cellular and molecular life sciences}, volume = {70}, journal = {Cellular and molecular life sciences}, number = {4}, publisher = {Springer}, address = {Basel}, issn = {1420-682X}, doi = {10.1007/s00018-012-1155-6}, pages = {689 -- 709}, year = {2013}, abstract = {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.}, language = {en} } @misc{GechevHilleWoerdenbagetal.2014, author = {Gechev, Tsanko S. and Hille, Jacques and Woerdenbag, Herman J. and Benina, Maria and Mehterov, Nikolay and Toneva, Valentina and Fernie, Alisdair R. and M{\"u}ller-R{\"o}ber, Bernd}, title = {Natural products from resurrection plants: Potential for medical applications}, series = {Biotechnology advances : an international review journal ; research reviews and patent abstracts}, volume = {32}, journal = {Biotechnology advances : an international review journal ; research reviews and patent abstracts}, number = {6}, publisher = {Elsevier}, address = {Oxford}, issn = {0734-9750}, doi = {10.1016/j.biotechadv.2014.03.005}, pages = {1091 -- 1101}, year = {2014}, abstract = {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/).}, language = {en} } @misc{GuptaDongDijkweletal.2019, author = {Gupta, Saurabh and Dong, Yanni and Dijkwel, Paul P. and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {Genome-Wide Analysis of ROS Antioxidant Genes in Resurrection Species Suggest an Involvement of Distinct ROS Detoxification Systems during Desiccation}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {763}, issn = {1866-8372}, doi = {10.25932/publishup-43729}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-437299}, pages = {22}, year = {2019}, abstract = {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.}, language = {en} } @article{GuptaDongDijkweletal.2019, author = {Gupta, Saurabh and Dong, Yanni and Dijkwel, Paul P. and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {Genome-Wide Analysis of ROS Antioxidant Genes in Resurrection Species Suggest an Involvement of Distinct ROS Detoxification Systems during Desiccation}, series = {International Journal of Molecular Sciences}, volume = {20}, journal = {International Journal of Molecular Sciences}, number = {12}, publisher = {Molecular Diversity Preservation International}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms20123101}, pages = {22}, year = {2019}, abstract = {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.}, language = {en} } @article{IvanovBeninaPetrovetal.2014, author = {Ivanov, Ivan and Benina, Maria and Petrov, Veselin and Gechev, Tsanko S. and Toneva, Valentina}, title = {Metabolic responses of gloxinia perennis to dehydration and rehydration}, series = {COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES}, volume = {67}, journal = {COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES}, number = {12}, publisher = {Publ. House of the Bulgarian Acad. of Sciences}, address = {Sofia}, issn = {1310-1331}, pages = {1657 -- 1662}, year = {2014}, abstract = {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.}, language = {en} } @article{MehterovBalazadehHilleetal.2012, author = {Mehterov, Nikolay and Balazadeh, Salma and Hille, Jacques and Toneva, Valentina and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {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}, series = {Plant physiology and biochemistry : an official journal of the Federation of European Societies of Plant Physiology}, volume = {59}, journal = {Plant physiology and biochemistry : an official journal of the Federation of European Societies of Plant Physiology}, publisher = {Elsevier}, address = {Paris}, issn = {0981-9428}, doi = {10.1016/j.plaphy.2012.05.024}, pages = {20 -- 29}, year = {2012}, abstract = {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.}, language = {en} } @misc{OmidbakhshfardNeerakkalGuptaetal.2020, author = {Omidbakhshfard, Mohammad Amin and Neerakkal, Sujeeth and Gupta, Saurabh and Omranian, Nooshin and Guinan, Kieran J. and Brotman, Yariv and Nikoloski, Zoran and Fernie, Alisdair R. and Mueller-Roeber, Bernd and Gechev, Tsanko S.}, title = {A Biostimulant Obtained from the Seaweed Ascophyllum nodosum Protects Arabidopsis thaliana from Severe Oxidative Stress}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {823}, issn = {1866-8372}, doi = {10.25932/publishup-44509}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445093}, pages = {26}, year = {2020}, abstract = {Abiotic stresses cause oxidative damage in plants. Here, we demonstrate that foliar application of an extract from the seaweed Ascophyllum nodosum, SuperFifty (SF), largely prevents paraquat (PQ)-induced oxidative stress in Arabidopsis thaliana. While PQ-stressed plants develop necrotic lesions, plants pre-treated with SF (i.e., primed plants) were unaffected by PQ. Transcriptome analysis revealed induction of reactive oxygen species (ROS) marker genes, genes involved in ROS-induced programmed cell death, and autophagy-related genes after PQ treatment. These changes did not occur in PQ-stressed plants primed with SF. In contrast, upregulation of several carbohydrate metabolism genes, growth, and hormone signaling as well as antioxidant-related genes were specific to SF-primed plants. Metabolomic analyses revealed accumulation of the stress-protective metabolite maltose and the tricarboxylic acid cycle intermediates fumarate and malate in SF-primed plants. Lipidome analysis indicated that those lipids associated with oxidative stress-induced cell death and chloroplast degradation, such as triacylglycerols (TAGs), declined upon SF priming. Our study demonstrated that SF confers tolerance to PQ-induced oxidative stress in A. thaliana, an effect achieved by modulating a range of processes at the transcriptomic, metabolic, and lipid levels.}, language = {en} } @article{OmidbakhshfardNeerakkalGuptaetal.2020, author = {Omidbakhshfard, Mohammad Amin and Neerakkal, Sujeeth and Gupta, Saurabh and Omranian, Nooshin and Guinan, Kieran J. and Brotman, Yariv and Nikoloski, Zoran and Fernie, Alisdair R. and Mueller-Roeber, Bernd and Gechev, Tsanko S.}, title = {A Biostimulant Obtained from the Seaweed Ascophyllum nodosum Protects Arabidopsis thaliana from Severe Oxidative Stress}, series = {International Journal of Molecular Sciences}, volume = {21}, journal = {International Journal of Molecular Sciences}, number = {2}, publisher = {Molecular Diversity Preservation International}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms21020474}, pages = {26}, year = {2020}, abstract = {Abiotic stresses cause oxidative damage in plants. Here, we demonstrate that foliar application of an extract from the seaweed Ascophyllum nodosum, SuperFifty (SF), largely prevents paraquat (PQ)-induced oxidative stress in Arabidopsis thaliana. While PQ-stressed plants develop necrotic lesions, plants pre-treated with SF (i.e., primed plants) were unaffected by PQ. Transcriptome analysis revealed induction of reactive oxygen species (ROS) marker genes, genes involved in ROS-induced programmed cell death, and autophagy-related genes after PQ treatment. These changes did not occur in PQ-stressed plants primed with SF. In contrast, upregulation of several carbohydrate metabolism genes, growth, and hormone signaling as well as antioxidant-related genes were specific to SF-primed plants. Metabolomic analyses revealed accumulation of the stress-protective metabolite maltose and the tricarboxylic acid cycle intermediates fumarate and malate in SF-primed plants. Lipidome analysis indicated that those lipids associated with oxidative stress-induced cell death and chloroplast degradation, such as triacylglycerols (TAGs), declined upon SF priming. Our study demonstrated that SF confers tolerance to PQ-induced oxidative stress in A. thaliana, an effect achieved by modulating a range of processes at the transcriptomic, metabolic, and lipid levels.}, language = {en} } @misc{PetrovHilleMuellerRoeberetal.2015, author = {Petrov, Veselin and Hille, Jacques and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {ROS-mediated abiotic stress-induced programmed cell death in plants}, series = {Frontiers in plant science}, volume = {6}, journal = {Frontiers in plant science}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2015.00069}, pages = {16}, year = {2015}, abstract = {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.}, language = {en} } @misc{PetrovHilleMuellerRoeberetal.2015, author = {Petrov, Veselin and Hille, Jacques and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {ROS-mediated abiotic stress-induced programmed cell death in plants}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {425}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-406481}, pages = {16}, year = {2015}, abstract = {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.}, language = {en} } @article{PetrovSchippersBeninaetal.2013, author = {Petrov, Veselin and Schippers, Jos and Benina, Maria and Minkov, Ivan and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {In search for new players of the oxidative stress network by phenotyping an Arabidopsis T-DNA mutant collection on reactive oxygen species-eliciting chemicals}, series = {Plant omics}, volume = {6}, journal = {Plant omics}, number = {1}, publisher = {Southern Cross Publ.}, address = {Lismore}, issn = {1836-0661}, pages = {46 -- 54}, year = {2013}, abstract = {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.}, language = {en} }