Tag Archives: Arabidopsis thaliana

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 sodium nitroprusside and S-nitrosoglutathione on pigment content and antioxidant system of tocopherol-deficient plants of Arabidopsis thaliana

N. M. Semchuk, Yu. V. Vasylyk, O. I. Kubrak, V. I. Lushchak

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

Sodium nitroprusside (SNP) and S-nitrosoglutathione (GSNO) were used as a source of exogenous nitric oxide (NO) to investigate their effects on biochemical parameters and antioxidant enzyme response in leaves of wild type Columbia and tocopherol-deficient vte4 and vte1 mutant lines of Arabidopsis thaliana plants and possible tocopherol involvement in regulation of antioxidant response under NO-induced stress. SNP enhanced the activity of the enzymes, that scavenge hydrogen peroxide in leaves of all studied lines, and increased glutathione reductase and glutathione-S-transferase activity there. In addition, it decreased the intensity of lipid peroxidation in vte1 mutant line leaves. At the same time, GSNO increased the levels of protein carbonyls and inactivated enzymes ascorbate peroxidase, guaiacol peroxidase and dehydroascorbate reductase in almost all investigated plant lines. In contrast to wild type, GSNO increased superoxide dismutase activity and decreased catalase activity and chlorophyll a/b ratio in the leaves of two mutant lines. It can be assumed that tocopherols in some way are responsible for plant protection against NO-induced stress. However the mechanisms of this protection remain unknown.

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.