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 - 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 - 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 - Shahnejat-Bushehri, Sara A1 - Allu, Annapurna Devi A1 - Mehterov, Nikolay A1 - Thirumalaikumar, Venkatesh P. A1 - Alseekh, Saleh A1 - Fernie, Alisdair R. A1 - Mueller-Roeber, Bernd A1 - Balazadeh, Salma T1 - Arabidopsis NAC Transcription Factor JUNGBRUNNEN1 Exerts Conserved Control Over Gibberellin and Brassinosteroid Metabolism and Signaling Genes in Tomato JF - Frontiers in plant science N2 - The Arabidopsis thaliana NAC transcription factor JUNGBRUNNEN1 (AtJUB1) regulates growth by directly repressing GA3ox1 and DWF4, two key genes involved in gibberellin (GA) and brassinosteroid (BR) biosynthesis, respectively, leading to GA and BR deficiency phenotypes. AtJUB1 also reduces the expression of PIF4, a bHLH transcription factor that positively controls cell elongation, while it stimulates the expression of DELLA genes, which are important repressors of growth. Here, we extend our previous findings by demonstrating that AtJUB1 induces similar GA and BR deficiency phenotypes and changes in gene expression when overexpressed in tomato (Solanum lycopersicum). Importantly, and in accordance with the growth phenotypes observed, AtJUB1 inhibits the expression of growth-supporting genes, namely the tomato orthologs of GA3ox1, DWF4 and PIF4, but activates the expression of DELLA orthologs, by directly binding to their promoters. Overexpression of AtJUB1 in tomato delays fruit ripening, which is accompanied by reduced expression of several ripeningrelated genes, and leads to an increase in the levels of various amino acids (mostly proline, beta-alanine, and phenylalanine), gamma-aminobutyric acid (GABA), and major organic acids including glutamic acid and aspartic acid. The fact that AtJUB1 exerts an inhibitory effect on the GA/BR biosynthesis and PIF4 genes but acts as a direct activator of DELLA genes in both, Arabidopsis and tomato, strongly supports the model that the molecular constituents of the JUNGBRUNNEN1 growth control module are considerably conserved across species. KW - Arabidopsis KW - tomato KW - fruit KW - growth KW - transcription factor KW - gibberellic acid KW - brassinosteroid KW - DELLA proteins Y1 - 2017 U6 - https://doi.org/10.3389/fpls.2017.00214 SN - 1664-462X VL - 8 PB - Frontiers Research Foundation CY - Lausanne ER -