Molecular Phsoiology
Armin Saed-Moucheshi; Fatemeh Sohrabi; Ali Shirkhani
Abstract
Reactive oxygen species (ROS) produced in organelles such as mitochondria, chloroplast, and peroxisome play an important role in plant signaling and signal transduction pathways. ROSs basically are able to regulate oxidation-reduction (known as redux) reactions, plant growth and defense responses to ...
Read More
Reactive oxygen species (ROS) produced in organelles such as mitochondria, chloroplast, and peroxisome play an important role in plant signaling and signal transduction pathways. ROSs basically are able to regulate oxidation-reduction (known as redux) reactions, plant growth and defense responses to environmental stimuli. Therefore, they affect every aspect at all life cycle stages of plants. ROSs such as hydrogen peroxide, superoxide, hydroxyl radicals, and singlet oxygen act as secondary messengers in plant cells to regulate a diverse range of protein functions (with post-translational modifications) and gene expression. They are produced naturally during the plant responses to environmental conditions and intra-/inter-cellular communications. Recent researches are indicating that ROS compounds play a key role in the plants response under both biotic and abiotic stresses. Biotic stresses such as fungi, viruses, mites, insects and other organisms, along with abiotic stresses such as drought, salinity and heavy metals, increase the production of ROS in plant cells. Plants possess various mechanisms to deal with the destructive effects of ROS increased production. ROS removal in plants is usually performed by two main groups of enzymatic and non-enzymatic antioxidant molecules. Antioxidant molecules play important roles in plant tolerance under stressful conditions by neutralizing ROS and converting them into water molecules. However, under severe stress conditions, plants are not able to eliminate the entire content of extra produced ROS molecules; as a result, the high amount of ROS causes oxidative stress in plants leading to various damages to the main components of the cells, such as proteins, lipids, DNA, carbohydrates, and ultimately cell death. There are still many unanswered questions regarding the plant specific responses to oxidative stress and regulation of cell communication during stress conditions. This review article tries to introduce the origin, location, and pathways of ROS production along with their types and effects on the cellular signal transduction system in stimulating adaptive responses of plants under stress conditions. Moreover, this review discusses the effectiveness of antioxidants systems in maintaining cell homeostasis and neutralizing the negative impacts of oxygen free radicals in plants.
Biotic and Abiotic stress
Narjes Fatahi; Hamid Sobhanian; Khadijeh Razavi; Tahmineh Lohrasebi; Gholamreza BakhshiKhaniki
Abstract
Environmental stresses have an irreversible effect on the production of bread wheat (Triticum aestivum L.), one of the most important crop plants. On the other hand, AP2/ERF members are the most important transcriptional regulators that influence plant growth and response to biotic and abiotic stresses. ...
Read More
Environmental stresses have an irreversible effect on the production of bread wheat (Triticum aestivum L.), one of the most important crop plants. On the other hand, AP2/ERF members are the most important transcriptional regulators that influence plant growth and response to biotic and abiotic stresses. To evaluate the mechanism of salt stress tolerance in wheat the activities of superoxide dismutase, ascorbate peroxidase and catalase in two tolerant wheat landraces (3623 and 3625) under salinity were investigated by completely randomized factorial experiment at control and 250 mM salinity in three replications. Seedlings were sampled at 0, 1, 3, 6, 12 and 24 h and 10 days after stress. The activity of enzymes was measured in the root and shoot of plants. The AP2-21 nucleotide sequence was extracted from the NCBI database and primers were designed and the gene fragment was isolated from wheat and then cloned and sequenced and confirmed by the presence of AP2 conserved domain. TaAP2-21 expression was evaluated by qPCR using specific primers and β-actin housekeeping genes. The results showed a significant difference in enzyme activity at different times compared to control in both tissues of both landraces and the highest was observed in short and medium-term stresses, however, apparently in long term stress the antioxidant mechanism of the enzymes is more active in 3623 than in 3625. Gene expression decreased significantly under salinity in both tissues. The TaAP2-21 gene is probably one of the inhibitors of the transcription of saline responsive genes and causes salt sensitivity in wheat.
Biotic and Abiotic stress
Saba Mokhlesian; Raheem Haddad; Ghasemali Garoosi; Maryam Ghannadnia
Volume 4, Issue 8 , March 2015, , Pages 11-20
Abstract
Various abiotic stresses lead to the overproduction of reactive oxygen species (ROS) in plants and cause to damage to proteins, lipids, carbohydrates and DNA. Antioxidative enzymes such as catalase and ascorbate peroxidase are activated to protect the plants against oxidative stress.Silicon is the second ...
Read More
Various abiotic stresses lead to the overproduction of reactive oxygen species (ROS) in plants and cause to damage to proteins, lipids, carbohydrates and DNA. Antioxidative enzymes such as catalase and ascorbate peroxidase are activated to protect the plants against oxidative stress.Silicon is the second most common element in soil that has beneficial effects in improving plants tolerance to drought stress.Accordingly, the effects of drought stress on semi-quantitative gene expression and enzymatic activities of both catalase and ascorbate peroxidase were investigated in two lines of two-row barley named CB-20315 (resistant) and CB-20213 (sensitive) in tillering stage in a greenhouse. The experiment was performed in a completely randomized design with three replications for three treatments of control, drought and silicon-drought (sodium silicate 2 mg / 1 kg), and analyzed in factorial experiment. RT-PCR semi-quantitative analysis revealed significant differences between treatments. The highest level of gene expression was observed for both enzymes in the silicon-drought treatment. The data showed that silicone application affect antioxidant enzymes activity to increase in both studied lines under drought stress. According to the results of this study it might be concluded that silicon participate in physiological and metabolic changes to enhance plants tolerance to drought stress.
Proteomics
Ghasem Hosseini Salkade; Davood Nasr Abadi
Volume 1, Issue 1 , March 2012, , Pages 1-11
Abstract
Rice is an excellent model cereal for molecular biology and genetics research. Salinity is a major factor limiting rice production world wide. The analysis of stress-responsiveness in plants is an important route to the discovery of genes conferring stress tolerance and their use in breeding programs. ...
Read More
Rice is an excellent model cereal for molecular biology and genetics research. Salinity is a major factor limiting rice production world wide. The analysis of stress-responsiveness in plants is an important route to the discovery of genes conferring stress tolerance and their use in breeding programs. To further understand the mechanism of plant response to salinity we employed a proteomic approach to profile the protein changes of rice 3th leaf and root under salt stress. Plants were grown in Yoshida nutrient solution and salt stress imposed after 25 days. Plants were treated by 100¬mM NaCl for 10. After that 3th leaves and total root were collected from control and salt stressed plants. The Na+ and K+ content of leaves/roots and several yield components changed significantly in response to short-term salt stress and their proteome patterns were analyzed using 2-DE in triplicates. The expression pattern of proteins significantly changed in all leaves/roots in response to stress. More than 488 and 345 protein were detected repeatedly in root and leaf 2Dgels respectively by software package. 107 proteins in root and 86 proteins in leaf of two genotypes showed significant response to stress. 3 protein in leaf gels and 2 protein in root gels were selected and identified by ESI-Q-TOF. The most important were Ferritin, Rubisco activase and ascorbat¬peroxidase in leaf and Peroxidase and Ascorbat¬peroxidase in root. All of them were enzyme and involved in detoxification and removal of reactive oxygen species (peroxidase, ascorbat¬peroxidase) Iron homeostasis (ferritin) or activation of other enzymes (rubisco¬activase).
