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Öğe A review of the potential involvement of small RNAs in transgenerational abiotic stress memory in plants(Springer Heidelberg, 2024) Junaid, Muhammad Daniyal; Chaudhry, Usman Khalid; Sanli, Beyazit Abdurrahman; Gokce, Ali Fuat; Ozturk, Zahide NeslihanCrop production is increasingly threatened by the escalating weather events and rising temperatures associated with global climate change. Plants have evolved adaptive mechanisms, including stress memory, to cope with abiotic stresses such as heat, drought, and salinity. Stress memory involves priming, where plants remember prior stress exposures, providing enhanced responses to subsequent stress events. Stress memory can manifest as somatic, intergenerational, or transgenerational memory, persisting for different durations. The chromatin, a central regulator of gene expression, undergoes modifications like DNA acetylation, methylation, and histone variations in response to abiotic stress. Histone modifications, such as H3K4me3 and acetylation, play crucial roles in regulating gene expression. Abiotic stresses like drought and salinity are significant challenges to crop production, leading to yield reductions. Plant responses to stress involve strategies like escape, avoidance, and tolerance, each influencing growth stages differently. Soil salinity affects plant growth by disrupting water potential, causing ion toxicity, and inhibiting nutrient uptake. Understanding plant responses to these stresses requires insights into histone-mediated modifications, chromatin remodeling, and the role of small RNAs in stress memory. Histone-mediated modifications, including acetylation and methylation, contribute to epigenetic stress memory, influencing plant adaptation to environmental stressors. Chromatin remodeling play a crucial role in abiotic stress responses, affecting the expression of stress-related genes. Small RNAs; miRNAs and siRNAs, participate in stress memory pathways by guiding DNA methylation and histone modifications. The interplay of these epigenetic mechanisms helps plants adapt to recurring stress events and enhance their resilience. In conclusion, unraveling the epigenetic mechanisms in plant responses to abiotic stresses provides valuable insights for developing resilient agricultural techniques. Understanding how plants utilize stress memory, histone modifications, chromatin remodeling, and small RNAs is crucial for designing strategies to mitigate the impact of climate change on crop production and global food security.Öğe Assessment of salt and drought stress on the biochemical and molecular functioning of onion cultivars(Springer, 2024) Chaudhry, Usman Khalid; Ozturk, Zahide Neslihan; Gokce, Ali FuatBackgroundSalt and drought stress are the main environmental constraints that limit onion growth and productivity. Turkiye is the fifth largest onion producer, whereas the stress conditions are increasing in the region, resulting in poor crop growth.Methods and ResultsA current study was conducted under greenhouse conditions according to a completely randomized design with factorial arrangements to evaluate the performance of onion cultivars. Plants were subjected to salt stress with an application of 750 mM NaCl and drought stress was applied by depriving plants of irrigation water for 20 days to measure biochemical and transcript changes. The antioxidant activities of the cultivars were quantified by using four different methods, i.e., 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays, cupric reducing antioxidant capacity, 2,2-Diphenyl-1-picrylhydrazyl, and ferric reducing antioxidant power (FRAP). The damage to pigments, phenolic, osmolytes, and hydrogen peroxide (H2O2) accumulation was also evaluated. Results revealed that the cultivars Elit and Hazar had higher H2O2, maximum damage to pigments, and least accumulation of phenolics and osmolytes under both stress conditions. The cultivar Sampiyon performance was better under salt stress but exhibited a poor antioxidant defensive mechanism under drought stress conditions. The remaining cultivars suggested a resilient nature with a higher accumulation of osmolytes, antioxidants and phenolics. The change in transcript levels further strengthened the response of resilient cultivars; for instance, they showed higher transcript levels of superoxide dismutase, ascorbate oxidase and transcription factors (WRKY70, NAC29). It helped alleviate the oxidative stress in tolerant cultivars and maintained the physio-biochemical functioning of the cultivars..ConclusionThe results of the current study will fill the gap of missing literature in onion at biochemical and molecular levels. Additionally, resilient cultivars can effectively cope with abiotic stresses to ensure future food security.Öğe Drought stress effects on morphophysiological and quality characteristics of commercial carrot cultivars(Tubitak Scientific & Technological Research Council Turkey, 2023) Junaid, Muhammad Daniyal; Ozturk, Zahide Neslihan; Gokce, Ali FuatThe effects of drought stress on plant growth and development are getting more pronounced due to increasing influence of climate change on environmental stresses. Current study was devised to explore the drought effects on eight commercial carrot cultivars, having different root colors as a base for further studies to understand the response of carrot. Drought stress for 10 days was applied to carrot plants at taproot formation stage in semicontrolled greenhouse. The results revealed that orange and yellow colored carrot cultivars exhibited the least decline in physiological functioning (relative water contents and dry matter) that assisted in maintaining higher yield and quality attributes in contrast to purple and black carrot cultivars. However, anthocyanin contents in nonpurple cultivars Tendersweet and Solar Yellow showed 72% decrease, whereas in purple carrot cultivars 3-fold increase was observed in Eregli Black and Cosmic Purple. Beta-carotene contents showed 59% decrease in cultivar Eregli Black under drought; however, it was increased in cultivars Solar Yellow and Coral Orange by 17% and 3%, respectively. Sugar accumulation exhibited variable response of carrot cultivars; minimal sucrose contents in cultivars Cosmic Purple, Solar Yellow and Tendersweet were detected after they were subjected to drought. Overall, the results showed that cultivars Atomic Red and Coral Orange performed well under water scarce condition. We believe this study may help the researchers to move forward in understanding the drought effects for the selection of promising cultivars to be used in development of tolerant varieties with breeding strategies.Öğe Exploitation of tolerance to drought stress in carrot (Daucus carota L.): an overview(Springernature, 2023) Junaid, Muhammad Daniyal; Ozturk, Zahide Neslihan; Gokce, Ali FuatDrought stress is a significant environmental factor that adversely affects the growth and development of carrot (Daucus carota L.), resulting in reduced crop yields and quality. Drought stress induces a range of physiological and biochemical changes in carrots, including reduced germination, hindered cell elongation, wilting, and disrupted photosynthetic efficiency, ultimately leading to stunted growth and decreased root development. Recent research has focused on understanding the molecular mechanisms underlying carrot's response to drought stress, identifying key genes and transcription factors involved in drought tolerance. Transcriptomic and proteomic analyses have provided insights into the regulatory networks and signaling pathways involved in drought stress adaptation. Among biochemical processes, water scarcity alters carrot antioxidant levels, osmolytes, and hormones. This review provides an overview of the effects of drought stress on carrots and highlights recent advances in drought stress-related studies on this crop. Some recent advances in understanding the effects of drought stress on carrots and developing strategies for drought stress mitigation are crucial for ensuring sustainable carrot production in the face of changing climate conditions. However, understanding the mechanisms underlying the plant's response to drought stress is essential for developing strategies to improve its tolerance to water scarcity and ensure food security in regions affected by drought.Öğe Recent advances in potato genomics, transcriptomics, and transgenics under drought and heat stresses: a review(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2015) Aksoy, Emre; Demirel, Ufuk; Ozturk, Zahide Neslihan; Caliskan, Sevgi; Caliskan, Mehmet EminSustainable potato production practices are crucial for food security and social sustainability in the future since potato is a highly nutritious food and it is considered as one of the most promising crops to reduce human hunger and poverty in the world due to its high yield potential. However, being a temperate crop, potato is exposed to various environmental stresses, including extended periods of drought and heat. The majority of potato genomics, transcriptomics, and transgenics studies concentrate on the characterization of molecular mechanisms governing cold hardiness of tubers and response and tolerance mechanisms against diseases. Likewise, potato breeding studies focus on increasing the yield, extending the postharvest storage, and developing cultivars that withstand biotic stresses. The number of genomics, transcriptomics, and transgenics studies of drought and heat tolerance in potato is limited, although they are necessary state-of-the-art research procedures to characterize and identify the regulatory mechanism underlying any stresses in order to develop new crop varieties that can tolerate harsh environmental conditions. For these reasons, this review focuses on recent advances in genomics, transcriptomics, and transgenics of drought and heat tolerance in potato.Öğe Subcellular localization and developmental regulation of cytosolic, soluble pyrophosphatase isoforms in Arabidopsis thaliana(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2014) Ozturk, Zahide Neslihan; Greiner, Steffen; Rausch, ThomasPyrophosphate (PPi) is the by-product of several reversible key reactions of primary metabolism. Thus, generated PPi should be removed by hydrolysis via pyrophosphatases to prevent accumulation and to drive anabolism. In plastids, a plastidic, soluble pyrophosphatase splits PPi released by ADPG pyrophosphorylase. The cytosolic PPi pool is believed to be hydrolyzed by tonoplast- and/or Golgi-integral H+-translocating pyrophosphatases. The Arabidopsis thaliana (L.) Heynh. genome encodes 6 soluble pyrophosphatase isoforms (PPas), 1 of which was shown to be localized in plastids. The remaining 5 of those PPas (PPas 1-5) are more similar to each other with highly conserved protein sequences. They all lack known targeting sequences and are thought to reside in the cytosol. To address their role and redundancy in plants, we performed (i) subcellular targeting of C-terminal PPa:EGFP fusions, (ii) analysis of transgenic promoter beta-glucuronidase (GUS) lines to depict differential expression during plant development, and (iii) transcript quantification via real-time PCR to corroborate promoter-GUS data. The results revealed pronounced tissue specificity and developmental regulation for each PPa isoform, but also partial redundancy with coexpression of several PPa isoforms in all plant tissues.