Cadmium Stress In Plants Research Articles

SlUPS, a U-box type E3 ubiquitin ligase gene of Lycopersicon esculentum Mill., confers the capacity of cadmium stress resistance in Arabidopsis

ABSTRACT Cadmium is not only seriously harmful to the growth and development of plants but threatens human health through the food chain. E3 ubiquitin ligase genes have been studied widely; however, whether it mediates cadmium stress in plants remains unclear. In this report, we provided evidence on the response of a U-box E3 ubiquitin ligase gene SlUPS to cadmium stress. The full-length CDS of SlUPS was 873 bp, with 223 amino acid residues. SlUPS was sufficiently induced by cadmium in leaf and root tissues. The expression of the SlUPS gene reached the maximum in leaves and roots in 3 and 9 h during CdCl2 treatment. The gene expression increased with progressively increasing concentrations of cadmium. The viability of yeast carrying pYES2-SlUPS, with SlUPS overexpressed, was higher than that in the control group. The transgenic Arabidopsis plants that overexpressed SlUPS showed a significantly higher germination rate and better growth than the control plants during the cadmium treatment. In summary, our study showed that SlUPS might positively regulate the plant response to cadmium stress. These results provided insights facilitating further investigations into the roles of U-box E3 ubiquitin ligase genes in heavy metal stress.

Photosynthetic light reactions in Oryza sativa L. under Cd stress: Influence of iron, calcium, and zinc supplements

Abstract Some mineral nutrients may help to alleviate cadmium stress in plants. Therefore, influence of Fe, Ca, and Zn supplements on photosynthesis light reactions under Cd stress studied in two Indian rice cultivars namely, MO-16 and MTU-7029 respectively. Exogenous application of both Fe and Ca ions helped to uphold quantum efficiency and linear electron transport during Cd stress. Also, recovery of biomass noticed during Cd treatment with Fe and Ca supplements. It was found that accumulation of carotenoids as well as non photochemical quenching enhances with Fe, Ca, and Zn supplements. Chlorophyll a/b ratio increased with Cd accumulation as a strategy to increase light harvest. Lipid peroxidation level was ascertained the highest during Cd plus Zn treatments. Above results point that both Fe and Ca ions supplements help to alleviate Cd stress on photosynthesis light reactions of rice plants.

The short-term responses of glutathione and phytochelation synthetic pathways genes to additional nitrogen under cadmium stress in poplar leaves

Earlier it was noticed that the supplementary nitrogen to nutritive solution of the cadmium stressed (Cd-stressed) plants can alleviate the toxic effects of this metal on the plants and improve plant growth performance. But the underlying mechanisms of such detoxification effect of nitrogen were not studied. In this study, a ten-day responses of related nitrogen-synthesized genes including γ-glutamylcysteine synthetase (γ-GCs), glutathione synthetase (ECGs) and phytochelatin synthase (PCs) involved in glutathione (ECG) and phytochelation (PC) synthetic pathways were examined. The plant growth performance and leaf chlorophyll content were examined at the final harvest. It was shown that the supplement of additional nitrogen to poplar plants under cadmium stress could significantly up-regulate the expression levels of γ-GCs, ECGs and PCs genes in plant leaves during the first 12 hours. Furthermore, cadmium stressed plants with additional nitrogen supplement showed significant enhancement in growth performance and increase in leaf chlorophyll content compared to sole cadmium stressed plants. Our results suggest that additional nitrogen could stimulate a short-term defense system in poplar plants through ECG and PC synthetic pathways. It is contribute to the alleviation of the toxic symptoms in polar plants caused by cadmium stress. This study provides a potential method to render harmless cadmium toxicity in stressed plants with nitrogen fertilization.

Role of salicylic acid in resistance to cadmium stress in plants.

We review and introduce the importance of salicylic acid in plants under cadmium stress, and provide insights into potential regulatory mechanisms for alleviating cadmium toxicity. Cadmium (Cd) is a widespread and potentially toxic environmental pollutant, originating mainly from rapid industrial processes, the application of fertilizers, manures and sewage sludge, and urban activities. It is easily taken up by plants, resulting in obvious toxicity symptoms, including growth retardation, leaf chlorosis, leaf and root necrosis, altered structures and ultrastructures, inhibition of photosynthesis, and cell death. Therefore, alleviating Cd toxicity in plants is a major aim of plant research. Salicylic acid (SA) is a ubiquitous plant phenolic compound that has been used in many plant species to alleviate Cd toxicity by regulating plant growth, reducing Cd uptake and distribution in plants, protecting membrane integrity and stability, scavenging reactive oxygen species and enhancing antioxidant defense system, improving photosynthetic capacity. Furthermore, SA functions as a signaling molecule involved in the expression of several important genes. Significant amounts of research have focused on understanding SA functions and signaling in plants under Cd stress, but several questions still remain unanswered. In this article, the influence of SA on Cd-induced stress in plants and the potential regulation mechanism for alleviating Cd toxicity are reviewed.

Links Between Ethylene and Sulfur Nutrition-A Regulatory Interplay or Just Metabolite Association?

Multiple reports demonstrate associations between ethylene and sulfur metabolisms, however the details of these links have not yet been fully characterized; the links might be at the metabolic and the regulatory levels. First, sulfur-containing metabolite, methionine, is a precursor of ethylene and is a rate limiting metabolite for ethylene synthesis; the methionine cycle contributes to both sulfur and ethylene metabolism. On the other hand, ethylene is involved in the complex response networks to various stresses and it is known that S deficiency leads to photosynthesis and C metabolism disturbances that might be responsible for oxidative stress. In several plant species, ethylene increases during sulfur starvation and might serve signaling purposes to initiate the process of metabolism reprogramming during adjustment to sulfur deficit. An elevated level of ethylene might result from increased activity of enzymes involved in its synthesis. It has been demonstrated that the alleviation of cadmium stress in plants by application of S seems to be mediated by ethylene formation. On the other hand, the ethylene-insensitive Nicotiana attenuata plants are impaired in sulfur uptake, reduction and metabolism, and they invest their already limited S into methionine needed for synthesis of ethylene constitutively emitted in large amounts to the atmosphere. Regulatory links of EIN3 and SLIM1 (both from the same family of transcriptional factors) involved in the regulation of ethylene and sulfur pathway, respectively, is also quite probable as well as the reciprocal modulation of both pathways on the enzyme activity levels.

Effect of Sulphur and Cadmium on Macronutrient Balance in Spring Wheat

The aim of the present experiment was to evaluate the changes in macronutrient contents and their accumulation in spring wheat (Triticum aestivum L.) ‘Zebra’ at different levels of sulphur and cadmium in the nutrient solution. In the experiment three levels of sulphur (2, 6 or 9 mM) and four concentrations of cadmium (0, 0.0002, 0.02 or 0.04 mM) were used. The present results indicate that cadmium exposure impaired the balance and accumulation of macronutrients in wheat plants. However, appropriate sulphur nutrition can at least partially restore ionic equilibrium and enhance macronutrient accumulation in cadmium exposed plants, especially at sulphur level of 6 mM. On the other hand, intensive sulphur nutrition generally increased cadmium accumulation in both roots and shoots, especially under 6 mM sulphur treatment. However, the sulphur dose of 6 mM concentration seems to be the most beneficial for the mineral status of cadmium stressed plants.

Hydrogen sulfide modulates cadmium-induced physiological and biochemical responses to alleviate cadmium toxicity in rice

We investigated the physiological and biochemical mechanisms by which H2S mitigates the cadmium stress in rice. Results revealed that cadmium exposure resulted in growth inhibition and biomass reduction, which is correlated with the increased uptake of cadmium and depletion of the photosynthetic pigments, leaf water contents, essential minerals, water-soluble proteins, and enzymatic and non-enzymatic antioxidants. Excessive cadmium also potentiated its toxicity by inducing oxidative stress, as evidenced by increased levels of superoxide, hydrogen peroxide, methylglyoxal and malondialdehyde. However, elevating endogenous H2S level improved physiological and biochemical attributes, which was clearly observed in the growth and phenotypes of H2S-treated rice plants under cadmium stress. H2S reduced cadmium-induced oxidative stress, particularly by enhancing redox status and the activities of reactive oxygen species and methylglyoxal detoxifying enzymes. Notably, H2S maintained cadmium and mineral homeostases in roots and leaves of cadmium-stressed plants. By contrast, adding H2S-scavenger hypotaurine abolished the beneficial effect of H2S, further strengthening the clear role of H2S in alleviating cadmium toxicity in rice. Collectively, our findings provide an insight into H2S-induced protective mechanisms of rice exposed to cadmium stress, thus proposing H2S as a potential candidate for managing toxicity of cadmium, and perhaps other heavy metals, in rice and other crops.

Galactoglucomannan oligosaccharides alleviate cadmium stress in Arabidopsis

Our study focused on the mediatory role of galactoglucomannan oligosaccharides (GGMOs) in plant protection against cadmium stress, examined mainly on the primary root growth of Arabidopsis thaliana. The application of GGMOs diminished the negative effect of cadmium on root length, root growth dynamics and also on photosynthetic pigment content. We tested the hypothesis that the effect of GGMOs is associated with decreased cadmium accumulation or its modified distribution. Cadmium distribution was observed chronologically from the first day of plant culture and depended on the duration of cadmium treatment. First, cadmium was stored in the root and hypocotyl and later transported by xylem to the leaves and stored there in trichomes. The protective effect of GGMOs was not based on modified cadmium distribution or its decreased accumulation. In cadmium and GGMOs+cadmium-treated plants, the formation of suberin lamellae was shifted closer to the root apex compared to the control and GGMOs. No significant changes between cadmium and GGMOs+cadmium variants in suberin lamellae development corresponded with any differences in cadmium uptake. GGMOs also stimulated Arabidopsis root growth under non-stress conditions. In this case, suberin lamellae were developed more distantly from the root apex in comparison with the control. Faster solute and water transport could explain the faster plant growth induced by GGMOs. Our results suggest that, in cadmium-stressed plants, GGMOs' protective action is associated with the response at the metabolic level.

Proline enhances antioxidative enzyme activity, photosynthesis and yield of Cicer arietinum L. exposed to cadmium stress

Abstract Seeds of chickpea inoculated with Rhizobium were sown in pots supplemented with different doses of cadmium (0, 25, 50 or 100 mg per kg of soil). At the stage of 30 days after sowing (DAS), the plants were sprayed with 20 mM solution of proline and were sampled at 90 DAS to assess the various parameters. The foliar treatment of proline resulted in the alleviation of the adverse effects generated by metal exposure, which was expressed in terms of the increase in plant growth. The activity of carbonic anhydrase in the cadmium-fed plants sprayed with proline was higher than that of control. The proline applied as foliar spray increased the photosynthetic attributes and yield characteristics in the cadmium-stressed plants. The activity of antioxidative enzymes increased with increasing concentration of cadmium. Maximum values were recorded in the plants exposed to 100 mg cadmium per kg of soil.

Effect of Cadmium Stress on the Growth, Antioxidative Enzymes and Lipid Peroxidation in Two Kenaf (Hibiscus cannabinus L.) Plant Seedlings

The effects of cadmium stress on the growth, antioxidative enzymes and lipid peroxidation in two kenaf plants, Fuhong 991 and ZM412, were analysed under control (0.5-strength Hoagland's nutrient solution) or five levels of cadmium stress (0.5-strength Hoagland's nutrient solution containing different concentrations of Cd2+). The leaves and roots of control and cadmium-stressed plants were harvested after 3 wk. At the same Cd concentration, the Cd tolerance index of Fuhong 991 was higher than that of ZM412, indicating that Fuhong 991 may be more tolerant to Cd than ZM412. The superoxide dismutase (SOD), catalase activity (CAT) and peroxidase (POD) activities fluctuated in the leaves of the Cd-stressed plants compared to the control, whereas the glutathione reductase activity (GR) was much larger than the control for Fuhong 991, ensuring that sufficient quantities of GSH were available to respond to the cadmium stress. In comparison to the control, the dynamic tendency of the SOD, CAT and POD activities in roots of the Cd-stressed plants all increased and then declined, but the POD activity of Fuhong 991 remained nearly unchanged at all of the stress levels. The increase in the enzyme activities demonstrated that Fuhong 991 was more tolerant to cadmium than ZM 412. The lipid peroxidation was enhanced only in the leaves of Cd-stressed ZM 412. These findings indicated that antioxidative activities may play important roles in Cd-stressed Fuhong 991 and ZM 412 and that the leaf and root cell membranes of Fuhong 991 have a greater stability than those of ZM 412. For pollution monitoring purposes, the GR activity in the roots and leaves may serve as a biomarker of Cd for Fuhong 991, whereas lipid peroxidation may serve as biomarker for ZM 412.

Фенольні сполуки як компоненти саліцилат-індукованої адаптивної відповіді рослин пшениці на токсичну дію кадмій хлориду

The effect of salicylic acid on the content of phenolic compounds and anthocyanins in wheat plants ( Triticum aestivum L.) affected by cadmium chloride was investigated. Increase in phenolic compounds content in cadmium-stressed plants was established. Preincubation with salicylic acid reduces phenol content, demonstrating growth activation, however increase in phenols content negatively correlates with photosynthetic productivity and nitrogen accumulation in leaves. Disproportion of distribution of the phenolic compounds in plant organism with significant predominance of their accumulation in root system was revealed. Salicylic acid increases content of anthocyanins in the shoots of 21-days-old plants under cadmium stress. An increase in phenols’ concentration in wheat plants caused by toxic effect of cadmium chloride affirms their functioning as prooxidants. Obtained results do not contradict the realization of antioxidant function by them. A decrease in phenol content in plant roots and shoots and increase in anthocyanin pool after preincubation with salicylic acid dsuggest their role as the components of adaptive response to cadmium stress. Keywords: salicylic acid, cadmium chloride, phenolic compounds, anthocyanins, Triticum aestivum L.

Salicylic acid enhances the efficiency of nitrogen fixation and assimilation in Cicer arietinum plants grown under cadmium stress

The aim of this study was to determine the effect of salicylic acid (SA) on nitrogen fixation and assimilation under conditions of cadmium stress in chickpea plants. Chickpea seeds were sown in pots containing 0, 25, 50, or 100 mg of cadmium per kilogram of soil. The foliage of the 30-day-old plants was sprayed with 10−5 M SA, and the activities of nitrogenase, nitrate reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase were investigated. SA exposure increased the number of nodules, fresh and dry nodule masses, leghemoglobin content, and activity of the nitrogen-fixing enzyme nitrogenase compared with the control conditions. Furthermore, SA application enhanced the activities of the enzymes involved in nitrogen assimilation, in both the control and cadmium-stressed plants. The overall results indicate that SA increases the fixation and assimilation of nitrogen regardless of whether the plants are grown in the presence or absence of cadmium.

Функціональний стан хлорофіл-білкових комплексів у листках рослин за дії іонів кадмію та саліцилати

Changes in status of chlorophyll-protein complexes of wheat and maize plants influenced by cadmium stress and different treatments with salicylate were studied. Observed modifications of pigment-protein complexes indicate adaptive effect of salicylic acid on cadmium-stressed plants. Impact of salicylic acid is species-specific and depends on stress sensitivity of plant. Features of salicylate and cadmium influence towards chlorophyll a and b , and possible mechanisms of salicylate role in regulation of status of chlorophyll-protein complexes under stressful conditions, are considered. Keywords: salicylic acid, cadmium, photosynthesis, chlorophyll-protein comple­xes, adaptation, stress, Triticum aestivum L., Zea mays L.

Two-Dimensional Liquid Chromatography Technique Coupled with Mass Spectrometry Analysis to Compare the Proteomic Response to Cadmium Stress in Plants

Plants are useful in studies of metal toxicity, because their physiological responses to different metals are correlated with the metal exposure dose and chemical state. Moreover a network of proteins and biochemical cascades that may lead to a controlled homeostasis of metals has been identified in many plant species. This paper focuses on the global protein variations that occur in a Populus nigra spp. clone (Poli) that has an exceptional tolerance to the presence of cadmium. Protein separation was based on a two-dimensional liquid chromatography technique. A subset of 20 out of 126 peaks were identified as being regulated differently under cadmium stress and were fingerprinted by MALDI-TOF. Proteins that were more abundant in the treated samples were located in the chloroplast and in the mitochondrion, suggesting the importance of these organelles in the response and adaptation to metal stress.

20S proteasome and accumulation of oxidized and ubiquitinated proteins in maize leaves subjected to cadmium stress

In order to examine the possible involvement of the 20S proteasome in degradation of oxidized proteins, the effects of different cadmium concentrations on its activities, protein abundance and oxidation level were studied using maize ( Zea mays L.) leaf segments. The accumulation of carbonylated and ubiquitinated proteins was also investigated. Treatment with 50 μM CdCl 2 increased both trypsin- and PGPH-like activities of the 20S proteasome. The incremental changes in 20S proteasome activities were probably caused by an increased level of 20S proteasome oxidation, with this being responsible for degradation of the oxidized proteins. When leaf segments were treated with 100 μM CdCl 2, the chymotrysin- and trypsin-like activities of the 20S proteasome also decreased, with a concomitant increase in accumulation of carbonylated and ubiquitinated proteins. With both Cd 2+ concentrations, the abundance of the 20S proteasome protein remained similar to the control experiments. These results provide evidence for the involvement of this proteolytic system in cadmium-stressed plants.

Translational asymmetry as a sensitive indicator of cadmium stress in plants: a laboratory test with wild-type and mutant Arabidopsis thaliana.

• Translational and bilateral asymmetry have been proposed as sensitive measures of stress in plants, but few studies have addressed the asymmetry-stress association for individuals grown under strictly defined conditions. Here, we assess the impact of cadmium (Cd) stress on various asymmetry measures in a wild-type and mutant strain of Arabidopsis thaliana. • Fitness measures (fresh weight, pod count and shoot length) and developmental stability (DS) measures (bilateral asymmetry and translational asymmetry (TA)) were compared between plants grown under different cadmium concentrations. • Cadmium stress sharply increased TA in both strains but had inconsistent effects on bilateral asymmetry. The TA effects were detected at a Cd concentration when effects on growth and reproduction were not yet evident. • Translational asymmetry, but not bilateral asymmetry, may therefore act as a sensitive indicator of cadmium stress and could be used to assess soil contamination in transplanted A. thaliana.