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    Aluminum Toxicity: A Case Study on Tobacco (Nicotiana tabacum L.)
    (Tech Science Press, 2023) Ozturk, Munir; Metin, Mert; Altay, Volkan; Kawano, Tomonori; Gul, Alvina; Unal, Bengu Turkyilmaz; Unal, Dilek
    Aluminum is an abundant metal in the earth's crust that turns out to be toxic in acidic environments. Many plants are affected by the presence of aluminum at the whole plant level, at the organ level, and at the cellular level. Tobacco as a cash crop (Nicotiana tabacum L.) is a widely cultivated plant worldwide and is also a good model organism for research. Although there are many articles on Al-phytotoxicity in the literature, reviews on a single species that are economically and scientifically important are limited. In this article, we not only provide the biology associated with tobacco Al-toxicity, but also some essential information regarding the effects of this metal on other plant species (even animals). This review provides information on aluminum localization and uptake process by different staining techniques, as well as the effects of its toxicity at different compartment levels and the physiological consequences derived from them. In addition, molecular studies in recent years have reported specific responses to Al toxicity, such as overexpression of various protective proteins. Besides, this review discusses data on various organelle-based responses, cell death, and other mechanisms, data on tobacco plants and other kingdoms relevant to these studies.
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    Ameliorative effect of Halopteris filicina extracts on growth parameters and genomic DNA template stability of tomato (Solanum lycopersicum) under lead chloride stress
    (Csiro Publishing, 2022) Unal, Dilek; Sevim, Gulcin; Varis, Gokay; Tuney-Kizilkaya, Inci; Unal, Bengu Turkyilmaz; Ozturk, Munir
    Lead is a toxic element that accumulates in agricultural soils through various anthropogenic sources. It inhibits the growth and development of plants and causes mutations in DNA. Macroalgae such as Halopteris filicina contain multifunctional components that may improve plant tolerance to lead stress. In this study, seeds of tomato (Solanum lycopersicum) were subjected to six treatments comprising two levels of lead exposure (60 or 120 mu M PbCl2) with or without H. filicina extract (0.5% in distilled water), a distilled water control, and a positive control (H. filicina extract) for 7 days. Physiological responses were investigated. Seedlings that had been treated with 60 and 120 mu M PbCl2 without H. filicina extract showed root growth reduction of 55% and 68.6%, respectively, relative to the control, whereas for 60 and 120 mu M PbCl2-treated seedlings with H. filicina extract applied, the reductions in root growth were lower, at 27.44% and 50.51%. The seedling viability index was decreased by 68.14% at 120 mu M PbCl2 application without H. filicina extract, whereas a 42.48% reduction was recorded for 120 mu M PbCl2-treated seedlings with H. filicina extract applied. Moreover, PbCl2 accumulation resulted in a decrease in leaf pigment content. Leaf pigment content was high in plants receiving the H. filicina extract. The rate of lipid peroxidation caused by PbCl2 was reduced with application of H. filicina extract. Genomic template stability was determined by using the inter simple sequence repeat-PCR technique, which revealed a decrease in DNA stabilisation with an increase in lead accumulation. However, this was alleviated by application of H. filicina extract. Our findings indicate that H. filicina extract both stimulates plant growth and protects from toxic effects by reducing accumulation of metals in the cell.
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    Effect of Putrescine on Low-Temperature Acclimation in Chlamydomonas reinhardtii
    (Tech Science Press, 2022) Inal, Muslum S.; Unal, Dilek; Unal, Bengu Turkyilmaz; Ozturk, Munir
    Putrescine is reported to be necessary for cold acclimation under low-temperature stress. In this study, the effect of low-temperature on some physiological and biochemical parameters has been investigated using the green algae Chlamydomonas reinhardtii. The lipid peroxidation rate, amount of Rubisco protein, activities of antioxidant enzymes and gene expression of polyamine biosynthesis (odc2, and spd1), heat shock proteins (hsp70c, hsp90a, and hsp90c), and PSII repair mechanisms (psba, rep27, and tba1) were determined to understand the low-temperature response. Exogenous putrescine application significantly increased Rubisco protein concentration and catalase enzyme activities under low-temperature stress. Moreover, real-time RT-PCR results and gene expression analysis showed that polyamine metabolism induced gene expression at low-temperatures in the first 24 h. In the same way, the gene expression of heat shock proteins (hsp70c, hsp90a, and hsp90c) decreased under low-temperature treatment for 72 h; however, application of putrescine enhanced the gene expression in the first 24 h. The results obtained indicated that molecular response in the first 24 h could be important for cold acclimation. The psba and tba1 expressions were reduced under low-temperatures depending on the exposure time. In contrast, the exogenous putrescine enhanced the expression level of the psba response to low-temperature at 24 and 72 h. The results obtained in this study indicate that putrescine could play a role in the PS II repair mechanisms under low-temperature stress.