Browsing by Author "Ozgur, Rengin"

Now showing 1 - 6 of 6

Citation - WoS: 7
Citation - Scopus: 6
Alternative electron sinks in chloroplasts and mitochondria of halophytes as a safety valve for controlling ROS production during salinity
(John Wiley and Sons Inc, 2024) Nil Demircan; Mustafa Cemre Sonmez; Turgut Yigit Akyol; Rengin Özgür Uzilday; I. Turkan; Karl Josef Dietz; B. Uzilday; Dietz, Karl-Josef; Uzilday, Baris; Demircan, Nil; Ozgur, Rengin; Turkan, Ismail; Akyol, Turgut Yigit; Sonmez, Mustafa Cemre
Electron flow through the electron transport chain (ETC) is essential for oxidative phosphorylation in mitochondria and photosynthesis in chloroplasts. Electron fluxes depend on environmental parameters e.g. ionic and osmotic conditions and endogenous factors and this may cause severe imbalances. Plants have evolved alternative sinks to balance the reductive load on the electron transport chains in order to avoid overreduction generation of reactive oxygen species (ROS) and to cope with environmental stresses. These sinks act primarily as valves for electron drainage and secondarily as regulators of tolerance-related metabolism utilizing the excess reductive energy. High salinity is an environmental stressor that stimulates the generation of ROS and oxidative stress which affects growth and development by disrupting the redox homeostasis of plants. While glycophytic plants are sensitive to high salinity halophytic plants tolerate grow and reproduce at high salinity. Various studies have examined the ETC systems of glycophytic plants however information about the state and regulation of ETCs in halophytes under non-saline and saline conditions is scarce. This review focuses on alternative electron sinks in chloroplasts and mitochondria of halophytic plants. In cases where information on halophytes is lacking we examined the available knowledge on the relationship between alternative sinks and gradual salinity resilience of glycophytes. To this end transcriptional responses of involved components of photosynthetic and respiratory ETCs were compared between the glycophyte Arabidopsis thaliana and the halophyte Schrenkiella parvula and the time-courses of these transcripts were examined in A. thaliana. The observed regulatory patterns are discussed in the context of reactive molecular species formation in halophytes and glycophytes. © 2024 Elsevier B.V. All rights reserved.
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) 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.
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) 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: 5
Citation - Scopus: 5
Proteomic profiling of an extreme halophyte Schrenkiella parvula with accelerated root elongation under mild salt stress.
(Elsevier B.V., 2024) Keriman Şekerci; Nahoko Higashitani; Rengin Özgür Uzilday; B. Uzilday; Atsushi Higashitani; I. Turkan; Ozgur, Rengin; Şekerci, Keriman; Turkan, Ismail; Higashitani, Nahoko; Higashitani, Atsushi; Uzilday, Baris
Increased salinity in soil is one of the impacts of climate change and a major problem for crop cultivation. Halophytes have the ability to survive in hypersaline environments and investigating their adaptation mechanisms is effective in imparting salt tolerance to plants. Recently we discovered a strategy by the extreme halophyte Schrenkiella parvula to promote primary root elongation a morpho-physiological response that may be given to have access to groundwater sources while reducing meristem DNA replication root hair development and biomass at moderate salinities around 100 mM NaCl. However when NaCl concentration exceeds 200 mM seedling root elongation is inhibited and seedlings change to respond to severe stress induced by salinity. To understand the interesting physiological and molecular mechanisms underlying primary root elongation at moderate salinity we performed a proteomic analysis using two-dimensional gel electrophoresis and MALDI-TOF MS. Ultimately a total of 300 different proteins were identified of which 20 showed significant increases and 25 showed significant decreases at 100 mM NaCl. Among the increased proteins proteins responding to abiotic stress such as glutathione transferases were found and among the decreased proteins proteins involved in glycolysis purine nucleotide synthesis and protein synthesis were found. Accumulation levels of proline an osmotic regulator that inhibits root growth were lower in S. parvula than in A. thaliana. On the other hand interestingly the expression levels of fructose-bisphosphate aldolase sucrose phosphatase and α-subunit of acetyl-CoA carboxylase increased. In addition increases in P5CDH an enzyme in the proline catabolism process and decreases in GLN and GDH in glutamate synthesis in S. parvula suggest that these may lead to a fine-tuning of proline content. For annexins a family of calcium-binding and membrane-bound proteins that regulate plant tolerance moderate salt treatment showed a significant decrease in SpANN7 a non-significant downtrend for SpANN2 but no change for SpANN1. These findings suggest that the 100 mM NaCl does not create a serious stress for S. parvula. We also performed gene expression analysis of these altered proteins between S. parvula and A. thaliana. Taken together in S. parvula roots 100 mM NaCl partially induced the redox homeostasis system stress response and proline-mediated osmoregulation moderately suppressing carbon metabolism nucleotide and protein synthesis to accelerate primary root elongation. © 2024 Elsevier B.V. All rights reserved.
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) 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.