Browsing by Author "Turkan, Ismail"

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Citation - WoS: 4
Citation - Scopus: 4
Deciphering melatonin biosynthesis pathway in Chenopodium quinoa: genome-wide analysis and expression levels of the genes under salt and drought
(SPRINGER, 2025-06-12) Seher Yolcu; Ece Fidan; Muhammed Fatih Kaya; Emre Aksoy; Ismail Turkan; Kaya, Muhammed Fatih; Turkan, Ismail; Fidan, Ece; Aksoy, Emre; Yolcu, Seher
Main conclusionIn this study we identified a total of ten melatonin biosynthesis genes (3 TDCs 2 TSHs 3 SNATs and 2 ASMTs) in Chenopodium quinoa through bioinformatics methods and analyzed physiological traits and gene expression levels in drought- and salt-treated plants with or without melatonin. Gene expression levels showed variations depending on tissues genotypes and abiotic stress.AbstractMelatonin is involved in distinct biological processes such as growth development and stress response in plants. The tryptophan decarboxylase (TDC) tryptamine 5-hydroxylase (T5H) serotonin N-acetyltransferase (SNAT) and N-acetylserotonin O-methyltransferase (ASMT) enzymes are involved in melatonin biosynthesis. Exogenous melatonin reduces the adverse effects of salt stress in different plants but the roles of melatonin biosynthesis pathway in quinoa (Chenopodium quinoa) remain elusive. This study aims to identify and characterize the melatonin biosynthetic genes encoding TDCs T5Hs SNATs and ASMTs in C. quinoa genome through bioinformatics methods and determine their transcript abundances under salt and drought stress. In total ten genes were identified in C. quinoa genome including 3 TDCs 2 TSHs 3 SNATs and 2 ASMTs. TDCs have a pyridoxal-dependent decarboxylase domain T5Hs possess a cytochrome P450 SNAT proteins contain the Acetyltransf_1 domain and ASMTs include the O-methyltransferase domain. We also examined some physiological characteristics such as growth and water relations along with electrolyte leakage. For that purpose two quinoa genotypes (Salcedo and Ames 1377) were subjected to salt and drought stress with or without melatonin. Exogenous melatonin remarkably reduced the negative effects of salt and drought on shoot length RWC and electrolyte leakage in the sensitive Salcedo genotype. However it showed limited impact on the stress-tolerant Ames 1377 genotype. Expression patterns showed variations depending on tissues genotypes and the type of abiotic stress. Promoter analysis indicated that the cis-elements in TDC T5H and SNAT promoters were mostly associated with stress-response while those in ASMT promoters were related to light response.
Citation - WoS: 1
Citation - Scopus: 1
Gene expression and mucilage adaptations to salinity in germination of extreme halophyte Schrenkiella parvula seeds
(ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER, 2025-03) Keriman Sekerci; Nahoko Higashitani; Rengin Ozgur; Atsushi Higashitani; Ismail Turkan; Baris Uzilday; Ozgur, Rengin; Şekerci, Keriman; Turkan, Ismail; Higashitani, Nahoko; Higashitani, Atsushi; Uzilday, Baris
Salinization is a significant global issue causes irreversible damage to plants by reducing osmotic potential inhibiting seed germination and impeding water uptake. Seed germination a crucial step towards the seedling stage is regulated by several hormones and genes with the balance between abscisic acid and gibberellin being the key mechanism that either promotes or inhibits this process. Additionally mucilage a gelatinous substance is known to provide protection against drought herbivory soil adhesion and seed sinking. However limited information is available on the structure and thickness of seed mucilage in halophytes under different salinity conditions. In this study the mucilage structure of the extreme halophyte Schrenkiella parvula was compared with the glycophyte Arabidopsis thaliana in response to salinity. We found differences in the expression levels of genes such as ABI5 RGL2 DOG1 ENO2 and DHAR2 which are involved in seed germination and antioxidant activity as well as in the mucilage structure of seeds of S. parvula and A. thaliana seeds at different salt concentrations. The responses of seed germination of S. parvula to salinity indicate that it is more salt-tolerant than A. thaliana. Additionally it was found that S. parvula mucilage decreased under salt conditions but not under mannitol conditions whereas in A. thaliana mucilage did not change under both conditions which is one of the adaptation strategies of S. parvula to salt conditions. We believe that these fundamental analyzes will provide a foundation for future molecular and biochemical studies comparing the responses of crops and halophytes to salinity stress.
Genome-Wide Analysis of DNA Methyltransferases in a Model Extremophyte, Schrenkiella Parvula: Transcriptional Dynamics during Development and under Salt Stress
(Wiley, 2026-04-21) Kakhki, Amin Mirshamsi; Turkan, Ismail; Jalilian, Ahmad; Yolcu, Seher; Sevindik, Emre
DNA methyltransferases (DMTs) are involved in plant stress response and development. Schrenkiella parvula, a model extremophyte, thrives under various stresses. However, the interplay between stress tolerance and epigenetic mechanisms remains elusive in extremophytes. In this study, DNA methyltransferases were identified in S. parvula for the first time and classified into 4 subfamilies: two methyltransferases (METs), three chromomethylases (CMTs), three domains rearranged methyltransferases (DRMs), and one DNA methyltransferase 2 (DNMT2). The predicted molecular weights (MWs) ranged from 43.54 (SpDNMT2) to 176.58 (SpMET2) kDa. Analysis of evolutionary selective pressure determined that the Ka/Ks values were lower than 1, indicating a strong negative selection during evolution. The cis-elements were associated with stress-response, hormonal regulation, light-response, and development. Spatiotemporal RNA-seq analysis revealed differential expression of DMTs under NaCl stress. In siliques treated with 150 mM NaCl before flowering, MET1, MET2, CMT1, and DRM2 showed downregulation in expression, while in siliques treated after flowering, DRM1 and DRM2 exhibited downregulation. The MET1 gene is specifically expressed in siliques. Gene expression patterns were dependent on tissue type, developmental stage, and the duration of salt stress. Differences in transcript levels of SpDMT genes under NaCl stress, along with cis-elements, suggest that SpDMTs might be involved in salt stress adaptation.
Citation - Scopus: 9
Heavy metal toxicity leads to accumulation of insoluble proteins and induces endoplasmic reticulum stress–specific unfolded protein response in Arabidopsis thaliana
(Springer, 2024-08-24) Nil Demircan; Rengin Özgür Uzilday; I. Turkan; B. Uzilday; Ozgur, Rengin; Turkan, Ismail; Uzilday, Baris; Demircan, Nil
Unfolded protein accumulation in the endoplasmic reticulum (ER) triggers ER stress leading to a unique transcriptomic response called unfolded protein response (UPR). While ER stress is linked to various environmental stresses its role in plant responses to heavy metal toxicity remains unclear. This study aimed to elucidate if heavy metals Fe Zn Cu and As induce ER stress in plants. For this purpose Arabidopsis thaliana seedlings were treated with Fe (200 400 µM) Zn (500 700 µM) Cu (25 50 µM) and As (250 500 µM) for 7 days which resulted in 50–70% decrease in plant growth. All treatments increased insoluble protein levels indicating unfolded protein accumulation with the highest induction observed for 50 µM Cu treatment (fivefold). Expressions of genes involved in the perception and signaling of ER stress (IRE1 bZIP28 bZIP60 bZIP17) indicate that Zn toxicity specifically induces bZIP28 but not the IRE1 branch of UPR. All metals except Fe also induced genes associated with protein folding in the ER (BIP1 BIP3 and CNX) and ER-associated protein degradation (ERAD) (HRD1). This finding indicates Zn Cu and As but not Fe cause ER stress in plants. Furthermore increased expression of ER oxidoreductase 1 (ERO1) suggests that metal toxicity also disrupts oxidative protein folding in the ER lumen. This study enhances our understanding of the intricate interplay between essential nutrients metal toxicity protein folding machinery and ER stress demonstrating that heavy metal toxicity has an ER stress component in plants alongside its established effects on energy metabolism membrane integrity and oxidative stress. © 2024 Elsevier B.V. All rights reserved.
Citation - WoS: 2
Citation - Scopus: 2
Melatonin mediated tolerance to benzalkonium chloride phytotoxicity through improved growth- photochemical reactions- and antioxidant system in wild-type and snat2 mutant Arabidopsis lines
(ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER, 2024-07) Evren Yildiztugay; Busra Arikan Abdulveli; Ceyda Ozfidan-Konakci; Ismail Turkan; Turkan, Ismail; Yildiztugay, Evren; Arikan Abdulveli, Busra; Abdulveli, Busra Arikan; Ozfidan-Konakci, Ceyda
Melatonin (Mel) is a phytohormone that plays a crucial role in various plant processes including stress response. Despite numerous studies on the role of Mel in stress resistance its significance in plants exposed to benzalkonium chloride (BAC) pollution remains unexplored. BAC a common antiseptic poses a threat to terrestrial plants due to its widespread use and inefficient removal leading to elevated concentrations in the environment. This study investigated the impact of BAC (0.5 mg L-1) pollution on wild-type Col-0 and snat2 knockout mutant Arabidopsis lines revealing reduced growth altered water relations and gas exchange parameters. On the other hand exogenous Mel (100 mu M) treatments mitigated BAC-induced phytotoxicity and increased the growth rate by 1.8-fold in Col-0 and 2-fold in snat2 plants. snat2 mutant seedlings had a suppressed carbon assimilation rate (A) under normal conditions but BAC contamination led to further A repression by 71% and 48% in Col-0 and snat2 leaves respectively. However Mel treatment on stressed plants was successful in improving Fv/Fm and increased the total photosynthesis efficiency by regulating photochemical reactions. Excessive H2O2 accumulation in the guard cells of plants exposed to BAC pollution was detected by confocal microscopy. Mel treatments triggered almost all antioxidant enzyme activities (except POX) in both Arabidopsis lines under stress. This enhanced antioxidant activity facilitated by foliar Mel application contributed to the alleviation of oxidative damage regulation of photosynthesis reactions and promotion of plant growth in Arabidopsis. In addition to corroborating results observed in many agricultural plants regarding the development of tolerance to environmental stresses this study provides novel insights into the action mechanisms of Mel under the emerging pollutant benzalkonium chloride.
Citation - WoS: 14
Citation - Scopus: 13
Revisiting the Potential of Seed Nutri-Priming to Improve Stress Resilience and Nutritive Value of Cereals in the Context of Current Global Challenges
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-06-28) Hayet Houmani; Imen Ben Slimene Debez; I. Turkan; Henda Mahmoudi; Chédly Abdelly; Hans Werner Koyro; Ahmed Debez; Mahmoudi, Henda; Koyro, Hans-Werner; Houmani, Hayet; Ben Slimene Debez, Imen; Turkan, Ismail; Debez, Ahmed; Abdelly, Chedly
Most crop species are cultivated in nutrient-deficient soils in combination with other challenging constraints that are exacerbated by the current climate changes. The significance of micronutrient shortage in stress management is often underappreciated although their deficiency restricts both plant growth and resistance to abiotic stresses and diseases. While the application of nutrients to growing plants is a potential strategy to improve plant resistance to abiotic stresses seed nutrient status may also play a role in crop stress tolerance as a storage and accumulation site of nutrients. To avoid hidden hunger problems developing countries need to increase domestic cereal production enhance their resilience to extreme weather events and improve their nutritional status and quality. Here we analyze the accumulated knowledge about the effects of nutri-priming in cereal crop species with a focus on mechanisms of application and stress tolerance keeping in mind the risk of crop damage mostly caused by global climate change which is driving an alarming increase in the frequency and intensity of abiotic stresses. We also propose new approaches to food production which may be promising solutions for global warming emerging diseases and geopolitical conflicts recognized as major drivers of food insecurity. © 2024 Elsevier B.V. All rights reserved.
Citation - WoS: 9
Citation - Scopus: 11
Role of Abscisic Acid- Reactive Oxygen Species- and Ca2+ Signaling in Hydrotropism-Drought Avoidance-Associated Response of Roots
(MDPI, 2024-04-28) Baris Uzilday; Kaori Takahashi; Akie Kobayashi; Rengin Ozgur Uzilday; Nobuharu Fujii; Hideyuki Takahashi; Ismail Turkan; Fujii, Nobuharu; Uzilday, Baris; Uzilday, Rengin Ozgur; Takahashi, Kaori; Turkan, Ismail; Takahashi, Hideyuki; Kobayashi, Akie
Plant roots exert hydrotropism in response to moisture gradients to avoid drought stress. The regulatory mechanism underlying hydrotropism involves novel regulators such as MIZ1 and GNOM/MIZ2 as well as abscisic acid (ABA) reactive oxygen species (ROS) and Ca2+ signaling. ABA ROS and Ca2+ signaling are also involved in plant responses to drought stress. Although the mechanism of moisture gradient perception remains largely unknown the sensory apparatus has been reported to reside in the root elongation zone rather than in the root cap. In Arabidopsis roots hydrotropism is mediated by the action of MIZ1 and ABA in the cortex of the elongation zone the accumulation of ROS at the root curvature and the variation in the cytosolic Ca2+ concentration in the entire root tip including the root cap and stele of the elongation zone. Moreover root exposure to moisture gradients has been proposed to cause asymmetric ABA distribution or Ca2+ signaling leading to the induction of the hydrotropic response. A comprehensive and detailed analysis of hydrotropism regulators and their signaling network in relation to the tissues required for their function is apparently crucial for understanding the mechanisms unique to root hydrotropism. Here referring to studies on plant responses to drought stress we summarize the recent findings relating to the role of ABA ROS and Ca2+ signaling in hydrotropism discuss their functional sites and plausible networks and raise some questions that need to be answered in future studies.
Role of Sirtuins in Heat Stress Tolerance under Elevated CO2 in Arabidopsis: Photosynthesis, Antioxidant System and Redox Regulation
(Springer, 2026-03-14) Alp-Turgut, Fatma Nur; Arikan-Abdulveli, Busra; Turkan, Ismail; Yildiztugay, Evren; Ozfidan-Konakci, Ceyda
Current knowledge about what the protective roles of elevated CO2 concentration (eCO(2)) on chlorophyll fluorescence, PSII photochemistry and antioxidant capacity of Arabidopsis with heat stress remains insufficient. Besides, there is a lack of information on the tolerance mechanism of plants against stress in the presence or absence of sirtuin genes. This study aimed to investigate how eCO(2) (800 ppm) mitigated heat stress (36 degrees C)-dependent oxidative damages through analyzing growth, water content, gas exchange, chlorophyll fluorescence, electron flux efficiency in PSII, antioxidant capacity and lipid peroxidation in Arabidopsis thaliana cv. Columbia-0 (Col-0) and its sirtuin-deficient mutant (srt2) plants. The focus was on investigating the function of the SRT2 gene, particularly in comparison with wild-type plants. Therefore, the sirtuin inhibitor (sirtinol, 1 & micro;M S) was applied to Col-0 plants and the effects of ambient (400 ppm) and eCO(2) heat (H) under stress were also examined. The reductions in growth and water content of heat stress-treated Col-0 and srt2 mutants were eliminated by eCO(2) exposure. The elevated CO2 was removed the reductions on chlorophyll fluorescence, carbon assimilation rate and carboxylation efficiency dependent by H stress in Col-0 plants, but not in srt2 mutants. S supplementation to Col-0 plants produced effects similar to those observed under stress across all measured parameters. While the structural indicators and electron fluxes of PSII and performance indices were disrupted by H stress, eCO(2) provided the positive effects on the photochemistry of PSII in the wild type of Arabidopsis. Interestingly, the eCO(2)-triggered alleviation against stress in srt2 mutants was not maintain. The induced (SOD and GR) and reduced activities (POX, APX, AsA/DHA and GSH redox state) of antioxidant systems point to increased H2O2 accumulation in both Col-0 (123%) and srt2 mutant (40%). Both of the Arabidopsis plants experienced oxidative stress as proved by the high levels of lipid peroxidation. eCO(2) under H stress resulted in remarkable decline in H2O2 accumulation, which contributed to POX and AsA regeneration in Col-0 and POX, AsA and GSH redox status in srt2. Sirtinol application to Col-0 plants also eliminated eCO(2)-mediated protection on TBARS content. This study provides the first evidence of SRT2 involvement in CO2-mediated heat stress tolerance.
Role of Sirtuins in Heat Stress Tolerance under Elevated CO2 in Arabidopsis: Photosynthesis, Antioxidant System and Redox Regulation
(Springer, 2026-03-14) Alp-Turgut, Fatma Nur; Arikan-Abdulveli, Busra; Turkan, Ismail; Yildiztugay, Evren; Ozfidan-Konakci, Ceyda
Current knowledge about what the protective roles of elevated CO2 concentration (eCO(2)) on chlorophyll fluorescence, PSII photochemistry and antioxidant capacity of Arabidopsis with heat stress remains insufficient. Besides, there is a lack of information on the tolerance mechanism of plants against stress in the presence or absence of sirtuin genes. This study aimed to investigate how eCO(2) (800 ppm) mitigated heat stress (36 degrees C)-dependent oxidative damages through analyzing growth, water content, gas exchange, chlorophyll fluorescence, electron flux efficiency in PSII, antioxidant capacity and lipid peroxidation in Arabidopsis thaliana cv. Columbia-0 (Col-0) and its sirtuin-deficient mutant (srt2) plants. The focus was on investigating the function of the SRT2 gene, particularly in comparison with wild-type plants. Therefore, the sirtuin inhibitor (sirtinol, 1 & micro;M S) was applied to Col-0 plants and the effects of ambient (400 ppm) and eCO(2) heat (H) under stress were also examined. The reductions in growth and water content of heat stress-treated Col-0 and srt2 mutants were eliminated by eCO(2) exposure. The elevated CO2 was removed the reductions on chlorophyll fluorescence, carbon assimilation rate and carboxylation efficiency dependent by H stress in Col-0 plants, but not in srt2 mutants. S supplementation to Col-0 plants produced effects similar to those observed under stress across all measured parameters. While the structural indicators and electron fluxes of PSII and performance indices were disrupted by H stress, eCO(2) provided the positive effects on the photochemistry of PSII in the wild type of Arabidopsis. Interestingly, the eCO(2)-triggered alleviation against stress in srt2 mutants was not maintain. The induced (SOD and GR) and reduced activities (POX, APX, AsA/DHA and GSH redox state) of antioxidant systems point to increased H2O2 accumulation in both Col-0 (123%) and srt2 mutant (40%). Both of the Arabidopsis plants experienced oxidative stress as proved by the high levels of lipid peroxidation. eCO(2) under H stress resulted in remarkable decline in H2O2 accumulation, which contributed to POX and AsA regeneration in Col-0 and POX, AsA and GSH redox status in srt2. Sirtinol application to Col-0 plants also eliminated eCO(2)-mediated protection on TBARS content. This study provides the first evidence of SRT2 involvement in CO2-mediated heat stress tolerance.
Citation - Scopus: 4
Roles of Reactive Carbonyl Species (RCS) in Plant Response to Abiotic Stress
(Humana Press Inc., 2024) Mustafa Cemre Sonmez; Side Selin Su Yirmibesoglu; Rengin Özgür Uzilday; B. Uzilday; I. Turkan; Ozgur, Rengin; Turkan, Ismail; Sonmez, Mustafa Cemre; Yirmibesoglu, Side Selin Su; Uzilday, Baris
Abiotic and biotic stress conditions lead to production of reactive carbonyl species (RCS) which are lipid peroxide derivatives and have detrimental effects on plant cells especially at high concentrations. There are several molecules that can be classified in RCS, among them 4-hydroxy-(E)-2-nonenal (HNE) and acrolein are widely recognized and studied because of their toxicity. The toxicity mechanisms of RCS are well known in animals but their roles in plant systems especially signaling aspects in metabolism need to be addressed. This chapter focuses on the production mechanisms of RCS in plants as well as how plants scavenge and modify them to prevent irreversible damage in the cell. We aimed to get a comprehensive look at the literature to summarize the signaling roles of RCS in plant metabolism and their interaction with other signaling mechanisms such as highly recognized reactive oxygen species (ROS) signaling. Changing climate promotes more severe abiotic stress effects on plants which also decrease yield on the field. The effects of abiotic stress conditions on RCS metabolism are also gathered in this chapter including their signaling roles during abiotic stresses. Different methods of measuring RCS in plants are also presented in this chapter to draw more attention to the study of RCS metabolism in plants. © 2024 Elsevier B.V. All rights reserved.
The Interaction between Histone Acetylation and Methylation with ROS Metabolism in Plants
(Springer, 2026-02-03) Ozgur, Rengin; Turkan, Ismail; Sevim, Gulcin; Keskinoglu, Merve; Gumus, B. Ozlem; Uzilday, Baris
Plants are constantly challenged by various abiotic stresses throught their life cycle and have evolved complex defence systems to ensure survival. Reactive oxygen species (ROS) are generated as byproducts of diverse metabolic pathways, acting not only as damaging molecules but also as essential signaling mediators at basal levels. Recent evidence indicates that enzymes involved in ROS/redox metabolism can influence gene expression by modulating histone modifications, particularly acetylation and methylation. Nevertheless, the precise molecular mechanisms linking ROS dynamics to epigenetic regulation remain poorly understood. This review synthesizes current knowledge on the interplay between ROS metabolism and global histone modifications in plants, highlighting how these interactions shape transcriptional reprogramming under stress conditions. Furthermore, we discuss how this crosstalk contributes to plant defence strategies against abiotic stresses such as drought, salinity, and heavy metal exposure, and we identify emerging questions and future research directions in this rapidly developing field.
The Interaction between Histone Acetylation and Methylation with ROS Metabolism in Plants
(Springer, 2026-02-03) Ozgur, Rengin; Turkan, Ismail; Sevim, Gulcin; Keskinoglu, Merve; Gumus, B. Ozlem; Uzilday, Baris
Plants are constantly challenged by various abiotic stresses throught their life cycle and have evolved complex defence systems to ensure survival. Reactive oxygen species (ROS) are generated as byproducts of diverse metabolic pathways, acting not only as damaging molecules but also as essential signaling mediators at basal levels. Recent evidence indicates that enzymes involved in ROS/redox metabolism can influence gene expression by modulating histone modifications, particularly acetylation and methylation. Nevertheless, the precise molecular mechanisms linking ROS dynamics to epigenetic regulation remain poorly understood. This review synthesizes current knowledge on the interplay between ROS metabolism and global histone modifications in plants, highlighting how these interactions shape transcriptional reprogramming under stress conditions. Furthermore, we discuss how this crosstalk contributes to plant defence strategies against abiotic stresses such as drought, salinity, and heavy metal exposure, and we identify emerging questions and future research directions in this rapidly developing field.