جستجوی مقالات مرتبط با کلیدواژه « آنزیم های آنتی اکسیدان » در نشریات گروه « بیوتکنولوژی و ژنتیک گیاهی »

To evaluate the expression pattern of genes encoding antioxidant enzymes catalase, ascorbate peroxidase and polyphenol oxidase under iron deficiency conditions in Fe- efficient (Pishtaz) and -inefficient (Falat) bread wheat cultivars, a CRD (completely randomized design) based factorial experiment was conducted with three replications. The cultivars were grown under iron deficiency (Less than 1.5 mg Fe/kg soil) and compared with normal conditions (10 mg Fe/kg soil). The relative expression levels of the above-mentioned genes were measured using Real-time PCR technique in the leaves and roots of the cultivars at two growth stages: vegetative (one month after germination) and reproductive (30% of heading). The results revealed a remarkable enhancement in calatalse expression in the roots of both cultivars in the vegetatative stage but it was higher in Fe-efficient cultivar than -inefficient one. The expression of this gene was decreased in leaves at the same stage as well as in the roots of both cultivars in the vegetative stage. The expression level of ascorbate peroxidase gene in the reproductive stage in the roots of Fe-inefficient cultivar was higher than that of -efficient one. In the vegetative stage, the expression of this gene increased in the leaves and roots of Fe-efficient cultivar, but it was decresed in Fe-inefficient cultivar. The relative expression level of polyphenol oxidase gene in the vegetative stage under iron deficiency conditions in the leaf increased almost three times, compared to the roots, while the expression of this gene decreased in the reproductive stage in both leaves and roots. By increasing the expression of both catalase and ascorbate peroxidase genes in the roots of both cultivars in the reproductive stage under iron deficiency conditions, it seems that bread wheat cultivars might reduce the deletrious effects of stress and maintain yield through transferring much iron to the seeds in the seed filling stage. The findings of the present study may increase our understanding of the important role of genes encoding antioxidant enzymes in Fe deficiency stress conditions.

Thyme is one of the most important medicinal plants which grows naturally in wide areas of range lands in Iran and simultaneously is cultured widely in Iran and other parts of the world. As Iran has placed in arid and semi-arid regions of the world, with actually low precipitation, doing projects in order to reveal the mechanisms or increase the drought tolerance of crop and medicinal plants has great value. Drought stress decreases the yield and quality of medicinal plants as well as crops. To investigate the mechanisms of drought tolerance of thyme plants and to evaluate the possibility of increasing of drought tolerance in these valuable medicinal plants, activity of some antioxidant enzymes and total soluble proteins were been analyzed in Thymus vulgaris L.in a complete randomized design experiment. After reaching to the adequate stage of growth, seedlings were grown in pots containing suitable soil, were subjected to different levels of drought stress (80% as control, 60% and 40% irrigation of field capacity(FC) as treatments). Results show that, drought stress had significant effect on total protein content as well as the activity of antioxidant enzymes. At 60% FC treatment and especially at 40% FC the amount of total soluble proteins drastically decreased. However; the activity of catalase increased at 60% FC treatment. The activity of peroxidase did not change significantly at 60% treatment but its activity decreased at 40% treatment. As a conclusion; it can be suggested that, one of the drought tolerance mechanisms of thyme is increasing of the activity of antioxidant enzymes especially the activity of catalase.

Basil (Ocimum basilicum L.)، a medicinal plant of the Lamiaceae family، is used in traditional Iranian medicine. Essential oils of basil are composed of phenylpropanoids. Chavicol o-methyl and eugenol o-methyl are the most important components in essential oil of basil. Chitosan، main compound of fungal species could be used as biotic elicitor to improve secondary metabolites. In the present study، the effect of chitosan on methylchavicol content، chavicol o-methyl transfrase gene expression and enzymes activity of catalase، ascorbate peroxidase was evaluated. The plants were treated at pre flowering stage with 2 g/L chitosan and harvested after 1، 2، 3، and 5 days. Essential oils analysis showed that methylchavicol increased under chitosan compare to untreated plants. Chavicol o-methyl transfrose gene expression and antioxidant enzymes activity increased significantly after chitosan. Totally، changes in gene expression in different harvest stages are consistent with methylchavicol changes. Thus، chitosan increased methylchavicol by increasing CVOMT gene expression.