Glutathione Depletion Due to Copper-Induced Phytochelatin Synthesis Causes Oxidative Stress in Silene cucubalus.
نویسندگان
چکیده
The relation between loss of glutathione due to metal-induced phytochelatin synthesis and oxidative stress was studied in the roots of copper-sensitive and tolerant Silene cucubalus (L.) Wib., resistant to 1 and 40 micromolar Cu, respectively. The amount of nonprotein sulfhydryl compounds other than glutathione was taken as a measure of phytochelatins. At a supply of 20 micromolar Cu, which is toxic for sensitive plants only, phytochelatin synthesis and loss of total glutathione were observed only in sensitive plants within 6 h of exposure. When the plants were exposed to a range of copper concentrations for 3 d, a marked production of phytochelatins in sensitive plants was already observed at 0.5 micromolar Cu, whereas the production in tolerant plants was negligible at 40 micromolar or lower. The highest production in tolerant plants was only 40% of that in sensitive plants. In both varieties, the synthesis of phytochelatins was coupled to a loss of glutathione. Copper at toxic concentrations caused oxidative stress, as was evidenced by both the accumulation of lipid peroxidation products and a shift in the glutathione redox couple to a more oxidized state. Depletion of glutathione by pretreatment with buthionine sulfoximine significantly increased the oxidative damage by copper. At a comparably low glutathione level, cadmium had no effect on either lipid peroxidation or the glutathione redox couple in buthionine sulfoximine-treated plants. These results indicate that copper may specifically cause oxidative stress by depletion of the antioxidant glutathione due to phytochelatin synthesis. We conclude that copper tolerance in S. cucubalus does not depend on the production of phytochelatins but is related to the plant's ability to prevent glutathione depletion resulting from copper-induced phytochelatin production, e.g. by restricting its copper uptake.
منابع مشابه
Response differences between Ectocarpus siliculosus populations to copper stress involve cellular exclusion and induction of the phytochelatin biosynthetic pathway.
Some populations of brown seaweed species inhabit metal-polluted environments and can develop tolerance to metal stress, but the mechanisms by which this is accomplished are still to be elucidated. To address this, the responses of two strains of the model brown alga Ectocarpus siliculosus isolated from sites with different histories of metal contamination exposed to total copper (CuT) concentr...
متن کاملEffects of Copper Nanoparticles in Prostate Normal and Cancer Cell Lines
Background and purpose: In clinical treatment of cancer, improving the efficacy of drugs and targeted drug delivery have always been a fundamental problem requiring more focused solutions. The purpose of this study was to investigate the protective effects of copper nanoparticles in prostate normal and cancer cell lines. Materials and methods: In this experimental study, different concentrati...
متن کاملMulberry Leaf Extract Attenuates Oxidative Stress-Mediated Testosterone Depletion in Streptozotocin-Induced Diabetic Rats
Background: It has been proposed that oxidative stress may contribute to the development of testicular abnormalities in diabetes. Morus alba leaf extract (MAE) has hypoglycemic and antioxidant properties. We, therefore, explored the impact of the administration of MAE on steroidogenesis in diabetic rats. Methods: To address this hypothesis, we measured the serum level of glucose, insulin, and f...
متن کاملThe Effect of Rebadioside A on Attenuation of Oxidative Stress in Kidney of Mice under Acetaminophen Toxicity
Background: Acetaminophen (APAP) overdose causes renal and hepatic injury. It is also believed that oxidative stress has a pivotal role in APAP-induced renal injury. Therefore, protective effects of different antioxidants have been examined in APAP-induced renal and hepatic toxicity models. Stevia rebadiana is a plant with a high degree of natural antioxidant activity in its leaf extract. T...
متن کاملNucleotide Sequence of the Gene for a Glutathione S-Transferase from Cell Suspension Cultures of Silene cucubalus.
Glutathione S-transferases (4) are involved in numerous plant physiological processes such as herbicide resistance (8), senescing flower petal response to ethylene (7), host response to pathogenic attack (2), and mammalian systems in the detoxification of xenobiotics. It has also been proposed that human glutathione S-transferase interacts with mercury, copper, and cadmium, therefore becoming a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Plant physiology
دوره 98 3 شماره
صفحات -
تاریخ انتشار 1992