To investigate the influence of jasmonic acid (JA) on morpho-physiological and biochemical characteristics of strawberry cv. Queen Elisa, under in vitro PEG-induced water stress, a factorial experiment based on completely randomized design (CRD) was conducted. PEG-induced water stress was imposed using polyethylene glycol (PEG6000) at three levels (0, 5 and 7% w/v), under three levels of JA application (0, 0.01 and 0.05 mM). The results indicated that PEG-induced water stress negatively impacted all studied morphological traits except for shoot fresh and dry weight. Furthermore, PEG-induced water stress had a decreasing effect on physiological traits including relative water content (RWC), photosynthesis pigments, membrane-stability index (MSI), and total proteins while it increased the activity of peroxidase (POD) and superoxide dismutase (SOD) enzyme and the content of malondialdehyde (MDA), hydrogen peroxide (H2O2), and proline. JA application showed an interaction effect with PEG-induced water stress on all studied traits except for SOD, POD, and total carbohydrate. Besides, based on the heat-map and principal component analysis results, three distinct groups were observed for physio-biochemical traits. Accordingly, the most effective treatment was the application of 0.05 mM JA under non-stressed condition. Altogether, the strawberry plants treated with higher JA concentrations could effectively cope with PEG-induced water stress adverse effects. Meanwhile, JA application improved strawberry growth attributes under both stress and non-stress conditions. In conclusion, the application of JA can be suggested as an effective way to alleviate deleterious impacts dehydration stress on strawberry under in vitro conditions. In vitro culture was used to study the effects of JA in strawberry under stress. PCA and heat map showed that relationships among studied parameters changed.

Jasmonic acid improved in vitro strawberry (Fragaria × ananassa Duch.) resistance to PEG-induced water stress

Quinoa is a traditional Andean seed crop highly tolerant to abiotic stresses. Since most seed crops cultivars are sensitive to drought stress, quinoa is considered as a valuable candidate for severe environmental conditions to which the plant is exposed. In this study we focused on the impact of hydropriming on drought tolerance in three quinoa cultivars (Q26, Q29 and Titicaca) in two arid regions of Iran. We observed that, under field conditions, quinoa responded to drought stress with a significant decrease in growth, yield component, seed yield and biochemical traits including photosynthetic pigments and relative water contents. In contrast, malondialdehyde, electrolyte leakage and proline concentration in all quinoa cultivars in both regions increased. However, seed priming significantly improved growth and seed yield. The results of the correlation analysis revealed that seed yield was highly positively related to pigments and proline concentration. Therefore, it could be suggested that these traits are efficient and reliable indicators for indirect selection of tolerant quinoa cultivars under drought stress conditions. In general, Q26 and Q29 were considered as superior cultivars for well-watered conditions and Titicaca cultivar was found relatively more drought tolerant than other cultivars. This study may contribute to the understanding of seed priming could be applied as an efficient approach to ameliorate the adverse effects of drought stress in quinoa cultivars.

Improved Quinoa Growth, Physiological Response, and Yield by Hydropriming Under Drought Stress Conditions

The toxic and non-essential metalloid arsenic (As) is ubiquitous in the environment with its absorption from the soil into the plants’ roots posing detrimental effects on the crop plants and hence the food availability and food security are also threatened. The present study was intended to reduce the As-induced toxicity in rice seedlings (Oryza sativa L.) by phosphate (PO43−). For this, three concentrations of potassium phosphate (KH2PO4), 50, 100 and 150 μM were supplemented along with 50 μM As exposure to hydroponically grown 7-day-old rice seedlings. Supplementation of PO43− significantly recovered arsenic-induced diminutions in growth parameters and photosynthetic pigment contents which were due to the significant increase in superoxide radical (SOR, O2•¯) and hydrogen peroxide (H2O2). Supplementation of 50 μM PO43− could significantly increase the activity of APX (ascorbate peroxidase) and GR (glutathione reductase) while 100 μM PO43− could increase the activity of DHAR (dehydroascorbate reductase) and monodehydroascorbate reductase (MDHAR). As the amount of PO43− was increased, the ratio of AsA/DHA (reduced to oxidized ascorbate) and GSH/GSSG (reduced to oxidized glutathione) was increased significantly due to increase in the reduced form of the non-enzymes i.e. AsA and GSH. The activity of SOD (superoxide dismutase) and GPX (guaiacol peroxidase) decreased significantly after a substantive increase in their activities due to As stress while the CAT (catalase) activity further enhanced after the supplementation of 50 and 100 μM PO43−. Thus, the As-induced oxidative stress in the rice seedlings was managed by concerted modulations in the activities of SOD, GPX, CAT and AsA-GSH cycle enzymes and metabolites.

Managing arsenic (V) toxicity by phosphate supplementation in rice seedlings: modulations in AsA-GSH cycle and other antioxidant enzymes.

With regards to the importance of drought stress and genotype screening under stress conditions, the current study was conducted to evaluate barley varieties in response to drought stress and find ...

Screening barley varieties tolerant to drought stress based on tolerant indices

Insilco identification and characterization of superoxide dismutase gene family in Brassica rapa.

The main objectives of this study were to find the possible structural association between the activity of enzymatic antioxidants and the grain yield of triticale plants as well as identifying the genotypic variability which might be effective on this association. Accordingly, expression levels of superoxide dismutase (SOD) isozymes (Mn-SOD, Cu/Zn-SOD, and Fe-SOD) were appraised to distinguish any possible relationship between SOD expression and drought resistance of triticale. A novel analytical method for distinguishing elite genotypes based on measured features was proposed. Additionally, a new programing based on SAS-language (IML) was introduced to estimate the genetic parameters rooted from combined ANOVA model (linear mixed model), which is capable of being used in any field study other than the current one. Thirty genotypes of triticale were studied under normal and drought stress conditions during 6 years (three different locations). Accordingly, based on the results of genetic variability, heatmap analysis, biplot graph, and clustering technique, two genotypes with the highest genetic distance were selected to appraise the differential expression profiling of three SOD isozyme in shoot and root organs. Field experiments and bioinformatics results showed that superoxide dismutase (SOD) was the most influential antioxidant in resistance of triticale to drought stress; therefore, it could be used as an indirect selection index in early stages to distinguish resistant genotypes to drought stress. Additionally, Mn-SOD and Fe-SOD showed roughly similar expression levels for both genotypes under drought stress. However, Cu/Zn-SOD expression level was higher in root and shoot of the tolerant genotype than the susceptible genotype. Heatmap analysis that is applied for the first time to screen suitable genotypes, showed to be highly capable of distinguishing elite genotypes and pointing out the proper features for selection criteria. Bioinformatics results indicated that SOD is more important than other enzymatic antioxidant for being considered as selection criteria or candidate gene for transgenic purposes. Based on expressional results, Mn-SOD announced as a general isozyme that is probably highly expressed in most of the species, while, Cu/Zn-SOD was introduced as a genotype specific isozyme that is likely more expressed in tolerant genotypes

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Superoxide dismutase (SOD) as a selection criterion for triticale grain yield under drought stress: a comprehensive study on genomics and expression profiling, bioinformatics, heritability, and phenotypic variability.

Role of Proline and Other Osmoregulatory Compounds in Plant Responses to Abiotic Stresses

Hydrogen peroxide and nitric oxide at low levels participate in various physiological functions, from plant development to defense responses including regulation of plant growth, pathogen infection, senescence, and seeds and rood development. In the present study, the stimulatory effects of Zataria multiflora essential oil (ZMEO) incorporated in the Persian gum on the activity and expression of superoxide-producing enzyme and nitric oxide-producing enzyme-like; NADPH oxidase (NOX), glutathione peroxidase (GPX), superoxide dismutase (SOD), catalase (CAT), nitric oxide synthase (NOS), nitrite reductase (NIR), polyamine oxidase (POX) and nitrate reductase (NAR) were investigated in the wheat seedlings. Carvacrol, γ-terpinene, α-terpinene, and p-cymene are the main components of ZMEO. ZMEO efficiently encapsulated in Persian gum dispersion and displayed low surface tension, low conductivity, low zeta-potential, acidic pH, nanoscale particle size and low Newtonian viscosity. Persian gum-ZMEO dispersion upregulated the activity and expression of NOX, SOD, CAT, GPX, NOS, NAR, NIR, and POX at 50 μg/ml as well as hydrogen peroxide and nitric oxide production. Briefly, the potent antioxidant capacity of the emulsified ZMEO implies that at low concentration it can effectively be used as a promising biostimulator to improve redox status in the wheat seedling.

Development of antioxidant materials based on Persian gum and Zataria essential oil: Modulation of superoxide-producing and nitric oxide-producing enzymes in wheat seedlings

Fatemeh Sohrabi

Papers

Superoxide dismutase (SOD) as a selection criterion for triticale grain yield under drought stress: a comprehensive study on genomics and expression profiling, bioinformatics, heritability, and phenotypic variability.

Screening barley varieties tolerant to drought stress based on tolerant indices

Role of Proline and Other Osmoregulatory Compounds in Plant Responses to Abiotic Stresses

Development of antioxidant materials based on Persian gum and Zataria essential oil: Modulation of superoxide-producing and nitric oxide-producing enzymes in wheat seedlings