Tag Archives: salt stress

Action of methyl jasmonate and salt stress on antioxidant system of Arabidopsis plants defective in jasmonate signaling genes

Т. О. Yastreb1, Yu. E. Kolupaev1,2, N. V. Shvidenko1, A. P. Dmitriev3

1Dokuchaev Kharkiv National Agrarian University, Ukraine;
e-mail: plant_biology@ukr.net;
2Karazin Kharkiv National University, Ukraine;
3Institute of Cell Biology and Genetic Engineering, National Academy of Sciences of Ukraine, Kyiv;
e-mail: dmitriev.ap@gmail.com

Role of jasmonate signaling in the regulation of stress-protective systems in Arabidopsis under salt stress remains insufficiently studied. For its clarification, comparative studies with mutants lacking various protein components of jasmonate signaling are advisable. In this connection, effects of methyl jasmonate (MJ, 50 μM) and salt stress (NaCl, 150 mM) on functioning of antioxidant and osmoprotective systems of wild-type Arabidopsis plants (Col-0) and ones defective in jasmonate signaling, namely coi1 (mutant for gene coding the protein COI1, which participates in removal of repressor proteins of transcription factors of jasmonate signaling) and jin1 (mutant defective in gene encoding the transcription factor JIN1/MYC2, one of the key in jasmonate signaling), were investigated. Salt stress inhibited growth of plants of all three genotypes. Treatment with MJ before salt stress positively influenced only the growth of wild-type plants. In contrast to mutants coi1 and jin1, Col-0 plants treated with MJ, under conditions of salt stress, kept close to the control values of water and total chlorophylls content, and the content of carotenoids increased. The coi1 plants under normal conditions differed from wild-type plants and jin1 mutants by reduced activity of guaiacol peroxidase and catalase and increased proline content. Treatment with MJ did not affect the activity of antioxidant enzymes and proline content in both mutants defective in jasmonate signaling. Under salt stress, the activity of superoxide dismutase, catalase and guaiacol peroxidase, as well as the content of proline and anthocyanins, in wild-type plants treated with MJ, were significantly higher than in control plants. The role of jasmonate-dependent protective systems in resistance of Arabidopsis plants to salt stress is discussed.

Effect of high sodium chloride concentrations on the pigment content and free-radical processes in corn seedlings leaves

Y. V. Vasylyk, V. I. Lushchak

Vassyl Stefanyk Precarpathian National University, Ivano-Frasnkivk, Ukraine;
e-mail: lushchak@pu.if.ua

The effect of sodium chloride on general morphometrical parameters of seedlings, and biochemical parameters in the leaves of corn seedlings was studied. Exposure to 100 and 200 mM NaCl slowed down the growth of stem and roots, whereas 100 and 200 mM NaCl during 24 h enhanced the concentration of chlorophylls, carotenoids, anthocyans, and thiobarbituric acid reactive substances. The decrease in protein carbonyl groups was found at 24-hour exposure to 200 mM salt. The treatment during 24, 48 and 72 h to 200 mM salt increased the level of total and high molecular mass thiols, whereas low molecular mass thiol content was by 20-25% higher at 48 h exposure to all used salt concentrations. The activity of guaiacol peroxidase was higher only at 24 h exposure to 100 and 200 mM salt, and catalase – at 50 mM during 48 h. At 72-hour exposure, catalase activity was by 27 and 41% higher in seedlings, exposed to 50 and 200 mM NaCl, respectively. Therefore, it is concluded the plant exposure to 50-200 mM salt initially developed oxidative stress, inducing adaptive response – an increase in antioxidant potential and efficiency of systems of energy production. That results in plant adaptation to unfavourable conditions.

Effect of preparations Methyure and Ivine on Са(2+)-ATPases activity in plasma and vacuolar membrane of corn seedling roots under salt stress conditions

M. V. Rudnytska, T. A. Palladina

Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv
e-mail: tatiana_palladina@ukr.net

Ca2+-ATPases regulate the functioning of Ca2+-dependent signaling pathway SOS which provides removal of Na+ from the cytoplasm of cells via Na+/H+-antiporters in saline conditions. The influence of synthetic preparations Methyure and Ivine on the Ca2+-ATPase activity was investigated. It was shown that exposition of corn seedlings in the presence of 0.1 M NaCl rather enhanced hydrolytic than transport activity of Ca2+-ATPases in plasma and vacuolar membrane of root cells. It was found that seed treatment with such preparations, especially Methyure, caused intensification of the both activities of Ca2+-ATPases, mainly in vacuolar membrane. The results indicate than salt protective activity of preparations, especially Methyure, is associated with increased Ca2+-ATPase activity, which regulates the functioning of Na+/H+-antiporters.

Ascorbate-glutathione cycle enzymes activity in zea mays leaves under salinity and treatment by adaptogenic compounds

O. O. Konturska, T. O. Palladina

M. G. Kholodny Institute of Botany, National Academy of Science of Ukraine, Kyiv;
e-mail: konturska@ukr.net

The effect of different salinity levels and synthetic compounds treatments on ascorbate-glutathione cycle enzymes activity in maize leaves has been investigated. One-day seedlings exposition with 0.05 М NaCl increased ascorbate peroxidase activity, whereas 10-day exposition did not affect it. However the exposition with 0.1 M NaCl, which is extreme for maize, decreased ascorbate peroxidase activity in leaves during 10 days. On the other hand glutathione reductase activity in leaves increased under both salt concentrations. Seeds treatments with Methyure and Ivine increased ascorbate peroxidase activity in the leaves of seedlings under 0.1 М NaCl, but did not affect glutathione reductase activity as compared to the salt control. The results obtained have shown differences of ascorbate-glutathione cycle enzymes responses to salt exposition of seedlings and the effects of adaptogenic compounds on the ascorbate-glutathione cycle via ascorbate peroxidase activation.

Effect of short-term salt stress on oxidative stress markers and antioxidant enzymes activity in tocopherol-deficient Arabidopsis thaliana plants

N. M. Semchuk, Yu. V. Vasylyk, Ok. V. Lushchak, V. I. Lushchak

Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine;
e-mail: lushchak@pu.if.ua

Changes of carotenoids and anthocyanins content, lipid peroxidation, and activity of antioxidant enzymes were studied in wild type and tocopherol-deficient lines vte1 and vte4 of Arabidopsis thaliana subjected to 200 mM NaCl during 24 h. The salt stress enhanced the intensity of lipid peroxidation to different extent in all three plant lines. Salt stress resulted in an increase of carotenoid content and activity of catalase, ascorbate peroxidase, guaiacol peroxidase and glutathione reductase in wild type and tocopherol-deficient vte1 mutant. However, the increase in anthocyanins concentration was observed in vte1 mutants only. In vte4 mutant, which contain γ-tocopherol instead of α-tocopherol, the response to salt stress occurred via coordinative action of superoxide dismutase and enzymes of ascorbate-glutathione cycle, in particular, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and glutathione-S-transferase. It can be concluded, that salt stress was accompanied by oxidative stress in three studied lines, however different mechanisms involved in adaptation of wild type and tocopherol-deficient lines to salt stress.

Gene expression of H(+)-pumps in plasma and vacuolar membranes of corn root cells under the effect of sodium ions and bioactive preparations

N. O. Kovalenko, T. A. Palladina

Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv;
e-mail: tatiana_palladina@ukr.net

Four isoforms of H+-ATPase of plasma membrane: MHA1, MHA2, MHA3, MHA4 are expressed in the corn seedling roots with prevalence of genes MHA3 і MHA4. The exposure of seedlings in the presence of 0.1 M NaCl activated the expression of MHA4 gene isoform, that demonstrates its important role in the processes of adaptation to salinization conditions. In vacuolar membrane, where potential is created by two Н+-pumps, sodium ions activated gene expression of only Н+-АТРase of V-type, taking no effect on the expression of Н+-pyrophosphatase. The seeds pretreatment by synthetic preparations Methyure and Ivine did not affect gene expression of Н+-pumps. Thus we can suppose that the ability of the above preparations to activate functioning of Н+-pumps in the presence of sodium ions is realized at the post-tranlation level.

Effect of sodium chloride and nitroprusside on protein carbonyl groups content and antioxidant enzyme activity in leaves of corn seedlings Zea mays L.

Yu. V. Vasylyk1, N. M. Semchuk1, Ok. V. Lushchak2, V. I. Lushchak1

1Department of Biochemistry and Biotechnology,
2Botanical Gardens of Vasyl Stefanyk Precarpathian National University,
Ivano-Frankivsk, Ukraine;
e-mail: lushchak@pu.if.ua

The effect of sodium nitroprusside (SNP) and sodium chloride (NaCl) on protein carbonyl group content and activity of antioxidant enzymes was investigated in leaves of maize seedlings. Incubation with NaCl and SNP+NaCl increased the content of carbonyl proteins after 24 h. Treatment with SNP+NaCl during 48 h showed lower and after 72 h higher carbonyl protein content than that in the control. Catalase activity was higher in the leaves of SNP+NaCl-treated than in the leaves of SNP-treated seedlings after 24 h. Ascorbate peroxidase activity increased after incubation with 0.2 mM SNP for 24 h. Significant increment of guaiacol peroxidase activity was obtained in all treated groups in comparison with the control after 72 h. Glutathione-S-transferase activity increased after 48 h seedling treatment with NaCl or SNP and 72 h seedling incubation with NaCl. Under experimental conditions used, glutathione reductase activity was virtually not affected. It is proposed that SNP can be used to prevent salt-induced oxidative stress in maize.

Effect of adaptogenic preparations on Na(+)/H(+)-antiporter function in plasma membrane of corn root cells under salinity conditions

N. O. Kovalenko, Zh. I. Bilyk, T. A. Palladina

Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv;
e-mail: tatiana_palladina@ukr.net

Salinity is a hard stress factor for plant organisms which negative effect is caused chiefly by sodium toxic for plants. Plant cells try to remove Na+ from their cytoplasm outside and to vacuolar space by secondary active Na+/H+-antiporters. Their functions can be intensified by gene engineering methods­ however we try do it with the help of non-toxic bio­active preparations. A comparison of their effect on the plasma membrane of Na+/H+-antiporters was carried out on corn seedling roots of Zea mays L. exposed at 0.1 M NaCl. Before we have established that Methyure used by seed pretreating possesses a high salt protective ability as against Ivine. It was found that without NaCl exposition Na+/H+-antiporter­ activity in root plasma membrane was nearly unnoticeable but increased slightly with seedling age. Methyure and Ivine did not influence its activity in control root seedling. One day 0.1 M NaCl exposition evoked a considerable increasing of Na+/H+-antiporter activity and its gene expression but these effects disappeared at 10 day NaCl exposition. Methyure use reinforced Na+/H+-antiporter activity and prolonged it at NaCl exposition without effect on its gene expression whereas Ivine effects on these indexes were insignificant. Obtained results showed that the salt protective capability of Methyure is connected with plasma membrane Na+/H+-antiporter activation which is realized on molecular level.