Susana M. Gallego

Universidad de Buenos Aires | UBA · Department of Biological Chemistry

Cadmium (Cd) pollution of agricultural soils is a growing global concern. Plant growth restriction is the main visible symptom of Cd toxicity, and this metal may be particularly harmful to the preformed, seminal root during the pre-emergence stage. In the present study, we focused on Cd phytotoxicity in seminal root growth, nutrient composition, re...

Nitric oxide (NO) is a small gaseous molecule regarded as an important signaling compound. It induces several developmental and physiological responses in plants, ranging from germination and senescence to photosynthesis and redox homeostasis. It can interact with phytohormones, like abscisic acid and auxins, inhibit programmed cell death (PCD), an...

Cadmium (Cd) pollution of agricultural soils is a growing global problem. Plant growth restriction is the main visible symptom of Cd toxicity, and this metal may be particularly harmful to the preformed, seminal root during the pre-emergence stage. In the present study, we focused on Cd phytotoxicity on seminal root growth, nutrient composition, re...

Cadmium is one of the most important contaminants and it induces severe plant growth restriction. In this study, we analyzed the metabolic changes associated with root growth restriction caused by cadmium in the early seminal root apex of wheat. Our study included two genotypes: the commercial variety ProINTA Federal (WT) and the PSARK::IPT (IPT) l...

Nitrogen (N) is a central mineral nutrient essential for plant development and growth. It is usually scarcely found in soils, so the knowledge of the overall plant N metabolism deserves substantial attention. Polyamines (PAs) are N‐containing low‐molecular‐weight compounds of polycationic nature involved in essential processes all throughout the li...

Cadmium (Cd) is a metal known to generate oxidative stress in plants and may be particularly harmful during germination. Herein, the growth and metabolic rearrangements of maize embryo axes subjected during the imbibition stage to Cd ions and other two well-known oxidative stressors, methyl viologen (MV) and hydrogen peroxide (H2O2), were assessed...

Copper (Cu) interferes with numerous biological functions in plants, including plant growth, which is partly governed by plant hormones. In the present study, Cu stress effect on the roots of pre-emerging maize seedlings in terms of growth, nutrient composition, protein modifications, and root hormone homeostasis was investigated, focusing on possi...

Cyclin-dependent kinase A (CDKA) is a key component for cell cycle progression. The catalytic kinase activity depends on the protein's ability to form an active complex with cyclins and on phosphoregulatory mechanisms. Cell cycle arrest and plant growth impairment under abiotic stress have been linked to different molecular processes triggered by i...

Cyclin dependent kinase A; 1 (CDKA; 1) is essential in G1/S transition of cell cycle and its oxidation has been implicated in cell cycle arrest during plant abiotic stress. In the present study, an evaluation at the molecular level was performed to find possible sites of protein oxidative modifications. In vivo studies demonstrated that carbonylati...

The complex formed by the cyclin-dependent kinase A (CDKA) and cyclin D is responsible for the G1-S transition in the plant cell cycle. Maize (Zea mays L) CDKA; 1 and CycD6; 1 were cloned and expressed in E. coli. The present study describes the optimization of both proteins production using a statistical approach known as response surface methodol...

In the present study we evaluated the pre-treatment (priming) of Arabidopsis thaliana plants with sodium nitroprusside (SNP), a NO-donor, as an interesting approach for improving plant tolerance to cadmium stress. We focused on the cell redox balance and on the methionine sulfoxide reductases (MSR) family as a key component of such response. MSR ca...

Microbes trigger stomatal closure through microbe-associated molecular patterns (MAMPs). The bacterial pathogen Pseudomonas syringae pv. tomato (Pst) synthesizes the polyketide toxin coronatine, which inhibits stomatal closure by MAMPs and by the hormone abscisic acid (ABA). The mechanism by which coronatine, a jasmonic acid-isoleucine analog, achi...

Plants are exposed to environmental stress, in natural and agricultural conditions.Nitric oxide (NO), a small gaseous molecule which plays important roles in plants, has been involved in many physiological processes, and emerged as an important endogenous signaling molecule in the adaptation of plants to biotic and abiotic stress. NO is produced fr...

Growth reduction caused by copper excess during plant photoautotrophic metabolism has been widely investigated, but information regarding early responses of root apical meristem (RAM) to toxic concentrations of this metal at the initial heterotrophic stage is certainly scarce. We analysed some determinants of seminal root growth in developing wheat...

In shaded wheat (Triticum aestivum L.) leaves, the suppression of blue radiation (BR) triggers senescence. This phenomenon is correlated to an increase in oxidative stress symptoms and a decrease of catalase (CAT) activity, among other traits. Previous data suggest that the radiation signal transduction pathway may involve changes in Ca2+ and H2O2...

In this investigation we analyzed in detail the consequences of water deficit during the first 4 days of wheat development, focusing on root growth as affected by eventual changes in cell cycle regulation and oxidative processes. Root elongation decreased under water restriction in correlation with the intensity of this limitation, but the total nu...

Proteins are molecules especially susceptible to oxidative modifications owing to their abundance and reactivity to radicals. Amongst the protein oxidative (redox) changes, carbonylation of the molecules represents an irreversible process that leads to the lost of protein functionality. The bulk of carbonylated proteins are produced as a result of...

The production of reactive oxygen species (ROS) in specific regions of Salix seedlings roots seems essential for the normal growth of this organ. We examined the role of different ROS in the control of root development in Salix nigra seedlings, and explored possible mechanisms involved in the regulation of ROS generation and action. Root growth was...

In a previous work we demonstrated that the suppression of blue light in shaded leaves of wheat increases their senescence rate and the development of oxidative stress symptoms. In order to better understand the interaction between the oxidative metabolism and light spectral quality in the regulation of leaf senescence, we studied the evolution of...

We previously showed that the antimicrobial peptide microcin J25 induced the over-production of reactive oxygen species with the concomitant release of cytochrome c from rat heart mitochondria via the opening of the mitochondrial permeability transition pore. Here, we were able to demonstrate that indeed, as a consequence of the oxidative burst, Mc...

Plant proteolytic system includes proteases, mainly localized inside the organelles, and the ubiquitin-proteasome pathway in both, the cytoplasm and the nucleus. It was recently demonstrated that under severe Cd stress sunflower (Helianthus annuus L.) proteasome activity is reduced and this results in accumulation of oxidized proteins. In order to...

Catalase (CAT) dismutates the reactive oxygen species H2O2 into water and dioxygen and in plants; it is located in peroxisomes and glyoxysomes. In the present study, we investigated the effect of cadmium (a well-known oxidative stress inducer) on catalase in roots and cotyledons of developing sunflower seedlings, at 10 microM and 100 microM. Althou...

One of the main antioxidant enzymes, catalase (CAT, EC 1.11.1.6), is capable of catalyzing the dismutation of H(2)O(2). This enzyme is involved in signal transduction pathway in plants, controlling the cellular level of this reactive oxygen species. Four different genes, CATA1-CATA4, were identified in Helianthus annuus L. cotyledons. Incubation of...

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. Trea...

The effect of oxidative stress induced by cadmium on growth parameters and on the balance between protein synthesis and degradation was studied in sunflower (Helianthus annuus L.) leaves. Plants were germinated for 10 days and then transferred to hydroponic medium devoid (control) or containing 100, 200 and 300 μM CdCl2. Analyses were performed bet...

Proteases are crucial for living cells and play a role in plant cell adaptation to environmental conditions. Oxidative stress produced oxidized proteins which are selectively degraded by proteases. To understand the role of proteolysis in response to metal stress, sunflower plants (a plant suitable for phytoremediation) were treated with 100 mu M o...

Ultraviolet-B (UV-B) radiation produces oxidative stress by increasing active oxygen species (AOS) such as singlet oxygen, superoxide anion, hydrogen peroxide and hydroxyl radicals. Recent studies confirm that hydrogen peroxide is a signaling molecule that mediates responses to abiotic and biotic stresses in plants. Peroxidases are a variety of enz...

Cadmium causes oxidative damage and hence affects nitrogen assimilation. In the present work we tested the relationship between the inactivation of the enzymes involved in nitrogen assimilation pathway (glutamine synthetase (GS)/glutamate synthase (GOGAT)) and the protein oxidation in nodules of soybean (Glycine max L.) plants under Cd2+ stress. Th...

Nitrogen fixation and assimilation in nodules and roots were studied in soybean (Glycine max L.) exposed to different levels of aluminium (Al) stress (0, 50, 200 and 500μM). Al at 500μM induced oxidative stress, which became evident from an increase in lipid peroxidation accompanied by a concomitant decline in antioxidant enzyme activities and legh...

Proteases are crucial for living cells and play a role in plant cell adaptation to environmental conditions. Oxidative stress produced oxidized proteins which are selectively degraded by proteases. To understand the role of proteolysis in response to metal stress, sunflower plants (a plant suitable for phytoremediation) were treated with 100 μM of...

Cadmium (Cd) homeostasis and detoxification in sunflower (Helianthus annuus L.) cells differing in Cd sensitivity/tolerance were studied by analyzing the glutathione-mediated antioxidant mechanism vis-à-vis phytochelatin biosynthesis in vitro. Calluses exposed to Cd-shock/-acclimatization (150μM) were assayed for oxidative stress, reduced glutathio...

The effect of moderate (50 M) and high (200 M) doses of Cd were studied in relation to polyamine (Pas) metabolism, proline level and the glutamine synthetase/glutamate synthase system (GS/GOGAT) activity in nodules and roots of soybean plants during 6 days of treatment. The lower Cd concentration increased putrescine (Put) in both nodules and roots...

Heavy metals are important environmental pollutants and their toxicity is a problem of increasing significance for ecological, evolutionary, nutritional, and environmental reasons. Plants posses homeostatic cellular mechanisms to regulate the concentration of metal ions inside the cell to minimize the potential damage that could result from the exp...

The relationship between cadmium-induced oxidative stress and nodule senescence in soybean was investigated at two different concentrations of cadmium ions (50 and 200M), in solution culture. High cadmium concentration (200M) resulted in oxidative stress, which was indicated by an increase in thiobarbituric acid reactive substances content and a de...

A relationship between the antioxidant defense system and salt tolerance in two types of sunflower calli differing in salt sensitivity was studied. No reduction in growth occurred in the NaCl-salt-adapted cell line (T) when grown on 175 mM NaCl but growth of the salt-stressed cell line (S) was reduced by 83%. Lipid peroxidation and protein oxidatio...

The nitrogen metabolism of soybean (Glycine max L.) nodules and roots was studied in plants subjected to two different concentrations (50 and 200 μM) of CdCl2. Nitrogenase activity was decreased in nodules treated with 200 μM Cd2+. In 50 μM Cd2+-treated plants, NH4+ content showed similar values to controls in nodules, but increased by 55% in roots...

The behavior of the antioxidant defense system was studied in sunflower cotyledons subjected to ultraviolet-B (UV-B) radiation. The two doses assayed (15.0 and 30.0 kJ m−2) induced oxidative damage, as evidenced by an increase in lipid peroxidation and a decrease in both chlorophyll content and superoxide dismutase activity. However, the reduced gl...

A relationship between the antioxidant defence system and metal iontolerance in two types of sunflower callus differing in metal ion sensitivitywas studied. The antioxidant defence system of callus subjected to anadaptationtreatment of Cd(II), Al(III) and Cr(III) responded differently to 150M of each metal compared with the corresponding controls u...

The antioxidant defence system of soybean (Glycine maxL.) nodules and roots was studied in plants subjected to three different concentrations (50, 100 and µ200 M ) of CdCl 2 . Cadmium (Cd)-induced oxidative stress was determined by lipid peroxidation, which remained unaltered in nodules and roots treated with 50 µM Cd(II). No changes were observed...

Polyamines have been reported as efficient antioxidant compounds in plants. Sunflower leaf discs, treated with 100 µM paraquat (PQ), a well known oxidative stress inducer, showed decreased levels of putrescine (Put), spermidine (Spd) and spermine (Spm) (between 33% and 80% with respect to the controls). Arginine decarboxylase (ADC) and ornithine de...

A relationship between the antioxidant defence system and salt tolerance in two clones of potato (Solanum tuberosum L.) differing in salt sensitivity was studied. The antioxidant defence system of the sensitive clone responded differently to 100 and 150 mM NaCl. At 100 mm NaCl, growth, dehydroascorbate reductase and catalase activities remained una...

Sunflower (Helianthus annuus L.) seeds were germinated and grown in the presence of 50, 100 and 200 µM CdCl2. The lower concentration (50 µM) of Cd2 ions produced slight decrease in reduced glutathione (GSH) content and overall increase (except superoxide dismutase) in antioxidant enzyme activities, and in H2O2 concentration. Chlorophyll content, l...

Two soybean (Glycine max L.) cultivars NaCl tolerant (377) and NaCl sensitive (411), were grown on medium with 150 mM NaCl. Salt treatment produced a 50% decrease in leghemoglobin (Lb) in 411, while in 377 no significant change was observed. Decreases of 50% in acetylene reduction activity (ARA) occurred in 411, while in the tolerant 377 values rem...

The relationship between heavy metal ion toxicity and oxidative stress in plant cells was studied. Leaf segments from 14 day old sunflower seedlings were incubated in solutions containing 0.5 mM Fe(II), Cu(II) or Cd(II) ions for 12 h in the light. Treatment with metal ions studied produced a decrease in chlorophyll and GSH contents as well as incre...

Relationship between cadmium ion toxicity and oxidative reactions in plant cells was studied. Helianthus annuus L. plants were treated with two concentrations (50 μM and 100 μM) of CdCl2 from 3 to 22 days after germination. Both cadmium concentrations caused a decrease in leaf chlorophyll content as well as an increase in lipid peroxidation rate. T...