Browsing by Author "Yuce, Merve"

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Ameliorative Effects of SL on Tolerance to Salt Stress on Pepper (Capsicum Annuum L.) Plants
(Elsevier France-Éditions Scientifiques Médicales Elsevier, 2025) Yuce, Merve; Aydin, Murat; Turan, Metin; Ilhan, Emre; Ekinci, Melek; Agar, Guleray; Yildirim, Ertan
Salinity is one of the most important problems that threaten agricultural production, especially in arid and semiarid areas. Strigolactones (SLs) are important in providing tolerance to various abiotic stresses in plants. The study was carried out in a hydroponic system to determine the effects of external GR24 (were applied as a foliar spray; 0, 10, and 20 mu M) applications at different doses on plant growth and some physiological, biochemical, and gene expression in two pepper genotype (Yalova and Maras,) grown under salt stress (0 and 100 mM NaCl). Plants were harvested and measured 10 days after the NaCl treatments. At the end of the research, it was determined that salt stress negatively affected plant growth in both genotype. Still, SL applications positively affected plant development both under normal and salt stress. While salt stress increased the amount of hydrogen peroxide (H2O2) and malondialdehyde (MDA), SL application caused a decrease in these parameters. Salt stress negatively affected the amount of chlorophyll and photosynthetic properties in both genotype, whereas SL applications mitigated this negative effect. SL applications caused a significant increase in antioxidant enzyme activities under both normal and salt stress conditions. SL content, which decreased with salt stress, increased with exogenous SL application. The content of other plant nutrients except sodium (Na) and chloride (Cl) decreased significantly in pepper seedlings grown under salt stress. External SL applications increased the uptake of these nutrients, especially under salt stress. In addition, the expression levels of CIPK3, CBL2, CCD7, DMAX2, PsbA, PsbB, PsbP1, TIP1;2, TIP5;1, SOS1, SOS2 and HKT2;2 genes were investigated in this study. It was observed that the expression levels of CCD7, DMAX2, SOS1, SOS2, and HKT2;2 genes increased with salinity stress, especially in the Maras, genotype, while SL applications decreased these expression levels. In the study, it was determined that especially exogenous 20 mu M SL application could significantly reduce the negative effects of salt stress in pepper.
Ameliorative Effects of Strigolactone on Tolerance to Lead Stress on Lettuce (Lactuca Sativa L.) Plants
(Nature Portfolio, 2025) Ucar, Sumeyra; Yuce, Merve; Yigider, Esma; Aydin, Murat; Turan, Metin; Ekinci, Melek; Yildirim, Ertan
Soil contamination by heavy metals, particularly lead (Pb), which is considered the second most toxic metal, poses serious risks to plants and humans due to its accumulation from various anthropogenic activities. Strigolactones (SLs) are a novel class of terpenoid lactones that play a vital role in regulating plant growth and development, particularly under stress conditions. This study aimed to investigate the impact of exogenous SL applications on plant growth and various physiological, biochemical, and molecular parameters in lettuce subjected to Pb stress. Pb stress harmed plant growth, whereas SL treatments improved growth parameters under both control and Pb stress conditions. While Pb stress increased the electrical conductivity (EC), malondialdehyde (MDA) and hydrogen peroxide (H2O2) content, SL applications caused a decrease in these parameters. Pb stress negatively affected chlorophyll content, whereas SL applications reduced negative effect. Pb caused an increase in superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) ascorbate peroxidase (APX), glutathione reductase (GR), glutathione s-transferase (GST) activities and Glucose-6-Phosphate Dehydrogenase (G6PD), 6-Phosphogluconate Dehydrogenase (6GPD). SL treatments significantly increased the activity of antioxidant enzymes in both control and Pb stress conditions. However, Pb stressed plants had lower nitrate reductase activity (NRA) than the control plants while SL treatments increased NRA compared to the non-treatments. Pb stress significantly reduced the uptake of essential nutrients in lettuce seedlings, whereas exogenous SL applications improved nutrient accumulation, particularly under Pb-stressed conditions. Additionally, mRNA expression profiles of nine stress-related genes in different tissues of lettuce were determined. Only Pb stress significantly decreased the expression of genes, particularly LsCCD8 and LsD14, in both tissues. The combined Pb and SL treatment significantly increased the expression of LsMAX2 in both tissues. These results suggest that exogenous SL applications can be an effective strategy to mitigate Pb-induced stress in lettuce by enhancing plant tolerance at physiological, biochemical, and molecular levels.
Chrysin Alleviates Salt Stress in Tomato by Physiological, Biochemical, and Genetic Mechanisms
(Elsevier, 2024) Ekinci, Melek; Turan, Metin; Aydin, Murat; Yuce, Merve; Agar, Guleray; Ors, Selda; Yildirim, Ertan
Soil salinity greatly reduces agricultural productivity, especially in dry and semi-arid regions, by interfering with physiological and biochemical processes. This research aimed to determine whether Chrysin (Chr) can mitigate the negative effects of salinity on growth parameters, antioxidant enzyme activity, and gene expression in tomato (Solanum lycopersicum L.) plants. Experiments were conducted in a semi-controlled greenhouse, with plants subjected to varying concentrations of sodium chloride (NaCl) (0 and 100 mM) and Chr (0, 0.1, 0.5, and 1.0 mM). Results revealed that salinity stress significantly reduced plant height, leaf area, and chlorophyll content while increasing hydrogen peroxide (H2O2), malondialdehyde (MDA), and proline levels, indicating oxidative stress. Chr application alleviated these detrimental effects by enhancing the activity of antioxidant enzymes such as catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), thereby reducing reactive oxygen species (ROS) accumulation. Additionally, Chr treatments improved plant water status and mineral content under salt stress. Gene expression analysis showed that Chr positively regulated the transcription of salt tolerance-related genes, including HKT1-1, HKT1-2, and PIP1-2, which are associated with sodium ion transport and water balance. These findings suggest that Chr can be an effective biostimulant for enhancing salt tolerance in tomato plants by modulating physiological, biochemical, and genetic mechanisms. This study provides insights into Chr's potential as a sustainable solution for improving crop resilience to salinity in agricultural practices. Further research is recommended to optimize Chr concentrations for maximum efficacy.
Chrysin Mitigates Copper Stress by Regulating Antioxidant Enzymes Activity, Plant Nutrient and Phytohormones Content in Pepper
(Elsevier, 2024) Yuce, Merve; Ekinci, Melek; Turan, Metin; Agar, Guleray; Aydin, Murat; Ilhan, Emre; Yildirim, Ertan
Copper (Cu) has an important role in physiological processes. High concentrations of Cu can cause toxic effects for plants. To evaluate the effect of Cu and chrysin (Chr) on the seedling growth, some physiological and biochemical properties of pepper, a factorial experiment in a completely randomized design was carried out. The treatments were T1= Control, T2= 0.1 mM Chr, T3= 0.5 mM Chr, T4= 50 mM Cu, T5= 50 mM Cu+ 0.1 mM Chr and T6= 50 mM Cu+ 0.5 mM Chr. Plant morphological characters were significantly affected by Cu and Chr treatments. The results showed a significant decrease in plant growth parameters due to Cu stress while Chr alleviated negative impacts of Cu on growth these parameters. The hydrogen peroxide (H2O2), malondialdehyde (MDA), prolin and sucrose content increased in pepper seedlings grown under Cu stress conditions. The MDA and H2O2 content showed a decrease with the effect of Chr treatment. Chr treatments also increased prolin and sucrose content of pepper plants under non-stressed conditions. Catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) enzyme activity elevated considerably compared to the control plants under Chr treatments. Moreover, higher values were observed for Chr treated plants under Cu stress. The findings of the study showed that Cu stress lowered all plant nutrient elements except for Cu content. 0.1 and 0.5 mM Chr treatments increased plant nutrient elements content of pepper seedlings under normal and Cu stress conditions. In conclusion, Chr mitigates Cu stress by regulating antioxidant enzymes activity, plant nutrient and phytohormones content in pepper.
N-Acetyl Mitigates Arsenic Stress in Lettuce: Molecular, Biochemical, and Physiological Perspective
(Elsevier France-Éditions Scientifiques Médicales Elsevier, 2024) Yuce, Merve; Yildirim, Ertan; Ekinci, Melek; Turan, Metin; Ilhan, Emre; Aydin, Murat; Ucar, Sumeyra
Agricultural land contaminated with heavy metals such as non-biodegradable arsenic (As) has become a serious global problem as it adversely affects agricultural productivity, food security and human health. Therefore, in this study, we investigated how the administration of N-acetyl-cysteine (NAC), regulates the physio-biochemical and gene expression level to reduce As toxicity in lettuce. According to our results, different NAC levels (125, 250 and 500 mu M) significantly alleviated the growth inhibition and toxicity induced by As stress (20 mg/L). Shoot fresh weight, root fresh weight, shoot dry weight and root dry weight (33.05%, 55.34%, 17.97% and 46.20%, respectively) were decreased in plants grown in As-contaminated soils compared to lettuce plants grown in soils without the addition of As. However, NAC applications together with As stress increased these growth parameters. While the highest increase in shoot fresh and dry weight (58.31% and 37.85%, respectively) was observed in 250 mu M NAC application, the highest increase in root fresh and dry weight (75.97% and 63.07%, respectively) was observed in 125 mu M NAC application in plants grown in As-polluted soils. NAC application decreased the amount of ROS, MDA and H2O2 that increased with As stress, and decreased oxidative damage by regulating hormone levels, antioxidant and enzymes involved in nitrogen metabolism. According to gene expression profiles, LsHIPP28 and LsABC3 genes have shown important roles in reducing As toxicity in leaves. This study will provide insight for future studies on how NAC applications develop resistance to As stress in lettuce.
Strigolactone Mitigates Nickel Toxicity by Regulating Nutrient Uptake, Antioxidant Defense, Vitamins and Phytohormones Biosynthesis in Pepper Seedlings
(Elsevier, 2026) Yildirim, Ertan; Yuce, Merve; Yaprak, Esra; Ucar, Sumeyra; Aydin, Murat; Turan, Metin; Oztemiz, Firuze
Here, pepper plants were subjected to non-stress control, control with strigolactone (SL), Nickel (Ni)-stress and Ni+ SL conditions to investigate the morpho-physiological and biochemical alterations in plant. Excess Ni produced significant negative impacts on plant's morphology, essential nutrients, and phytohormones content as compared to control plants. However, it caused tremendous increment of hydrogen peroxide (H2O2), and malondialdehyde (MDA) and the effects were further triggered by increasing concentration. Consistently, Ni induced the activity of enzymatic antioxidants like superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) compared to control plants. It also showed downregulation of photosystem II (PSII)-related CaPsb2, aquaporin-related CaPIP1-1 and CaPIP1-2, and dehydrin-related CaDHN3 transcripts. Exogenous SL improved plant's phenotypes in control plants and greatly repaired the morphology of Ni-stressed plants. Although, sucrose accumulation was greatly enhanced by SL in Ni-stressed plants, proline content was only heightened under 500 mu M Ni. SL showed tremendous enhancement of nutrients and phytohormones in control plant and caused significant restoration of those in Ni-stressed plant. However, SL significantly reduced reactive oxygen species (ROS) in the Ni-stressed plants. This reduction correlated with elevated levels of both non-enzymatic and enzymatic antioxidants, despite the decline observed in CAT activity under extreme Ni-stressed condition. SL also showed modulation of CaPsbD transcript under Ni stress. Taken together, SL (20 mu M) produced the best results in improving most of parameters studied here, as evidenced by our multivariate analysis. The findings claim the crucial role of exogenous SL in growth and mitigation of Ni-toxicity in pepper.
Unraveling the Role of Chrysin in Mitigating Cadmium Toxicity in Pepper by Improving Antioxidant Defense, Phytohormone Biosynthesis and Photosystem II and Aquaporins Related Transcripts☆
(Elsevier Sci Ltd, 2025) Yuce, Merve; Ucar, Sumeyra; Yildiz, Mehmet; Aydin, Murat; Turan, Metin; Ghosh, Totan Kumar; Yildirim, Ertan
Cadmium (Cd) is the most dangerous and prevalent one which has tremendous impacts on global food security. Although chrysin (Chr) has been extensively studied in Cd stressed animal system, the role of this valuable flavonoid in plants is yet to be clarified. Therefore, this study was designed to determine the effects of different doses of Chr (0, 50, 150 and 300 mu M) on some physiological, biochemical and gene expression in pepper grown under Cd stress (0 and 50 mM Cd). Cd stress significantly arrested relative water, proline, essential nutrients and phytohormones content when compared to non-stressed plants. However, Cd stress caused significant enhancement of hydrogen peroxide (H2O2), melondialdehyde (MDA), and tissue electrolyte leakage (EL) and reduction of enzymatic antioxidants like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD), and expression of photosystem II (PSII) and aquaporin (AQPs) related transcripts compared to non-stressed plants. Compared to Cd stress, Chr positively regulated the formation of H2O2, MDA and %EL, antioxidant enzyme activity, as well as accelerated the synthesis of indole-3-acetic acid (IAA), gibberellic acid (GA) and cytokinins (CK) and reduced the level of abscisic acid (ABA), which was significantly increased by Cd stress. In addition, Chr demonstrated enhanced expression of CaPsbB, CaPsbD, CaPsb1 and CaPsb2, CaPIP1-2 and CaTIP5-1 in both root and shoots and when compared to Cd stressed plants. The findings obtained at the end of the study show that Chr is very important for alleviation of Cd toxicity in pepper plants.