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The beet cyst nematode (BCN) (Heterodera schachtii), and beet curly top virus-severe (BCTV-Svr) (Curtovirus betae) are two important pathogens of sugar beet fields worldwide. Therefore, the reaction of 14 genotypes was separately assessed, using Jolgeh and Sanetta cultivars as susceptible and resistant controls, respectively, in completely randomized design experiments for BCN and BCTV-Svr. Reactions were based on the cyst and egg counts and symptoms severity index. Experiments were performed in the greenhouse of Tarbiat Modares University, Tehran, Iran, and were repeated twice independently. Based on the results of initial experiments, the S1-960090, S1-940324, S1-960294, and S1-960284 genotypes resistant to the BCN were selected for further investigation. Furthermore, the reaction of the four selected genotypes to BCN, BCTV-Svr, and the combination (mixture) of the two pathogens was evaluated by analyzing their growth, physiological, and biochemical characteristics, and virus accumulation. Resistant genotypes showed higher levels of defense-related enzymes such as catalase, guaiacol peroxidase, and polyphenol oxidase, whereas susceptible genotypes exhibited significant reductions in photosynthesis, greenness, and chlorophyll a, b, and carotenoid content compared to non-inoculated and resistant plants. This is the first study conducted to search for dual-resistance sources against two devastating pathogens that frequently occur in the sugar beet-growing regions of Iran. Based on the results of this experiment, genotypes S1-960090 and S1-940324 were identified as resistant to both pathogens and are recommended for breeding purposes.
 

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Background: Cells have complex network of antioxidant enzymes that protect cells from induced damages by reactive oxygen species (ROS). Catalase and superoxide dismutase are known for their role as primary protection against oxidative stress. Oxidative damage is an important risk factor in age-related macular degeneration disease (AMD). For the first time in this study the impact of genetic polymorphisms of SOD1 and CAT with AMD has been examined. Hence, the association between genetic polymorphisms of catalase (CAT) C-262T, Cu/Zn superoxide dismutase (SOD1) A251G and risk of exudative AMD has been investigated. Methods: This study was carried out on blood samples collected from 112 exudative AMD patients and 112 healthy individuals. Genotyping of CAT C-262T and SOD1A251G was done by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. Differences in the frequencies were estimated using the χ2 test and risk was estimated with a logistic regression after adjusting for smoking, working place and age status. Results: There was significant difference between CAT CT+TT genotype and AMD disease (P=0.009, OR=0.38, 95%CI=0.18-0.78). Also T-allele has a significant association with risk of AMD and decreases risk of disease (P=0.036, OR=0.59, 95%CI=0.36-0.96), but there was no significant differences between SOD1A251G and variant homozygous and heterozygous frequencies in patients compared to controls (P=0.589, OR=0.77, 95%CI=0.3-1.96). Conclusions: The data presented suggest that the T-allele in CAT genotypes can increase catalase expression and activity, as a result of which generation of reactive oxygen species (ROS) can be decreased. Therefore it is suggested that increased expression of CAT as a result of T-allele in CAT genotypes and existence of T-allele in CAT genotypes is associated with decreased risk of AMD.

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The biocontrol activity of two isolates of Candida membranifaciens against grey mold of apple fruit caused by Botrytis mali and their ability to induce biochemical defense responses in apple tissue were investigated. Apple fruit (Malus domestica) wounds were inoculated with 50 µl yeast suspension (1 × 10⁷ CFU/ml) of C. membranifaciens followed 4 h later by 20 µl of conidial suspension of B. mali (1 × 10⁵ conidia/ml). The apples were then incubated at 20 ºC for 8 days. Lesion diameter sizes were measured 4 and 8 days after pathogen inoculation. In addition to controlling grey mold, these two isolates of C. membranifaciens caused increases in peroxidase and β-1, 3-glucanase activities. These isolates also caused inhibition in catalase activity. The accumulation of phenolic compounds was increased in apple fruit treated with antagonists and inoculated with B. mali and reached its highest level 6 days after treatment. The ability of C. membranifaciens to affect H2O2-metobolizing enzymes and increase levels of β-1, 3-glucanase activity and phenolic compounds may be some of mechanisms responsible for its biocontrol activity.  

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The aims of this study were to assess the effects of drought stress on peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activities as well as free proline content and growth parameters of Pistacia khinjuk seedlings under drought stress. Therefore, the one-year seedlings of Pistacia khinjuk subjected to water stress (25%, 50%, 75%, and 100% field capacity) for 8 months in greenhouse condition. Results showed that drought stress decreased height, collar diameter, shoot dry weight and root dry weight of P. khinjuk seedlings. But it had different effects onantioxidant enzyme activities in root and shoot of P. khinjuk seedlings. Drought stress increased CAT activity in shoot and root of seedlings and its activity was higher in 25% field capacity (FC) than other treatments. Also, the POD enzyme activity increased in root and shoot of seedlings subjected to drought stress. The SOD activity was at the lowest level in 100% FC than other treatments. The results also showed that free proline accumulation was lower in well watered seedlings and increased under drought stress.

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To investigate the effect of droughtstress on chlorophyll content, enzymatic responses and some growth characteristics of Acacia victoriae seedlings and the effect of super-absorbent polymers (SAP) in reducing drought stress, a split plot experiment based on the completely randomized design was conducted. The treatments included four levels of drought stress (15, 30, 60 and 100% of field capacity) and four levels of SAP (0, 0.2, 0.4 and 0.6% weight percentages). The results of ANOVA showed a significant effect of drought stress on all growth characters, chlorophyll content and catalase and peroxidase enzymes activity, while the SAP didn't show any significant effect on the weight and areas of the leaves. The interaction effect between drought stress and SAP on the weight, number of leaves, proportion of root dry weight to aerial organs, chlorophyll and peroxidase enzyme activity was also significant. The effect of drought stress on reducing the number of the leaves, leaf area, length, volume and surface of roots and also increasing the root dry weight to aerial organs dry weight ratio, amount of chlorophyll and activity of antioxidant enzymes was significant. The different levels of SAP could absorb and hold water and consequently reduce the effect of drought stress and improve the growth characteristics and reduce the activity of catalase and peroxidase enzymes.

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The effect of salicylic acid (SA) on induction of resistance against root-knot nematode (Meloidogyne javanica) and the effect of M. javanica to induce biochemical defense responses in tomato (Solanum lycopersicum L.) roots at six-leaf stage were investigated. Meanwhile, the effect of different concentrations of SA on mortality of second stage juveniles of M. javanica was examined. Changes in the activity of cytoplasmic peroxidase (POX), catalase (CAT) and phenylalanine ammonia lyase (PAL) enzymes in the roots of tomato seedlings were measured during seven successive days after inoculation with M. javanica in greenhouse. SA was used as soil drench and leaf spray. The efficiency of treatments were evaluated by measuring diameter of galls, number of galls per plant, number of egg masses per plant, number of eggs per individual egg mass, root and foliage fresh weights. The results showed that use of SA as soil drench and leaf spray significantly reduce diameter of galls 28% and 32%, number of galls per plant 40% and 44%, number of egg masses per plant 45% and 49% and number of eggs per individual egg mass 53% and 55% compared to control (inoculated with nematode only). The activity of the enzymes (POX, CAT and PAL) increased in comparison with plants treated with distilled water. The maximum level of larva mortality was observed at 7 mM SA with no significant difference at concentration of 6 mM. SA caused 21.2% mortality of larvae at concentration of 5 mM.    

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Expression analysis was carried out to characterise the level and time of expression of two senescence related cDNAs, LSC650 and LSC54, in Brassica napus and Arabidopsis thaliana. The extent of DNA sequence similarity showed that the LSC650 gene may en-code the catalase homologous to Cat3 in Arabidopsis thaliana the role of which is to scav-enge H2O2. Also, LSC54 gene encodes a metallothionein protein that may detoxify metal ions in plant cells. Plant leaves were characterised at different developmental stages by biochemical analysis, including chlorophyll and protein assays. Northern analysis re-vealed strong levels of LSC650 and LSC54 expression in senescent leaves and lower levels in mature green leaves, but very weak or no expression in young leaves in B. napus. The transcription of genes, LSC650 and LSC54, was almost at the same level with few changes between maturity and senescence in leaves of Arabidopsis at different plant growth phases, being due to a possible unknown stress. The results indicate that both genes stud-ied may act as antioxidants, and have a role in scavenging active oxygen species (AOS) caused by catabolism of macromolecules during senescence.

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Grape trunk diseases are critical problems for grapes from the time of planting to the harvest stage. Grapes are susceptible to 29 fungal diseases due to their perennial woody trunk, so identifying and managing them is crucial. Among the methods of controlling these diseases, feeding with mineral fertilizers to reduce leaf symptoms resulting from the toxic secretions of fungi living in the woody part of the tree is of great importance. To manage these diseases, a mixture of fertilizers including calcium chloride CaCl₂, 466 g, magnesium nitrate Mg(NO₃)₂, 403 g, seaweed extract (75 ml) and sterile distilled water 466 ml per liter of foliar spraying on the selected treatments in Sohrabi’s garden were used once every 20 days. Guaiacol peroxidase, catalase and leaf area index were measured in Sohrabi’s garden during 2017 and 2018 and were compared with the control. In the treatments sprayed with the fertilizers, the average amount of guaiacol peroxidase enzyme was 12.72 µl compared to the control (10.6 µl) and the average amount of catalase enzyme was 83.68 µl compared to the control (31.85 µl). The average size of the leaf area in the foliar treatments in Sohrabi’s garden was 11564 mm², compared to the control that was 4959 mm². The severity of the disease in the sprayed treatments (19.95 %) was lower than the control (56.6 %). These results are due to the increase in the leaf surface, which increases the amount of photosynthesis, and the increase in guaiacol peroxidase and catalase, which reduce the oxidative stress resulting from fungal secretions, which resulted in decreasing symptoms in foliar treatments.

 

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Trichosanthes kirilowii, an important economic plant in China, is sensitive to chilling. To investigate the effect of abscisic acid (ABA) treatment on the chilling tolerance of Trichosanthes kirilowii Maxim, different concentrations of ABA were sprayed on Trichosanthes kirilowii leaves and the resulting catalase (CAT) and superoxide dismutase (SOD) activities and the malondialdehyde (MDA) content in the leaves were determined. The results indicated that at 4 ºC, the CAT and SOD activities increased at first and then decreased with increasing ABA concentration. By contrast, the MDA content decreased at first and then increased. They both had an extreme value when sprayed with 5.0 or 7.5 mg L^-1 ABA. A real-time polymerase chain reaction was performed to investigate the influence of exogenous ABA on the CAT gene expression of Trichosanthes kirilowii leaves. The results indicated that at 4 ºC, the CAT relative gene expression showed a high degree of positive correlation with the enzyme activities of CAT and SOD, and a negative correlation with MDA content. These results led to three conclusions. First, exogenous ABA exhibits significant effect on the chilling tolerance of Trichosanthes kirilowii. Second, exogenous ABA significantly increases the enzyme activities of CAT and SOD under cold environments. Finally, under cold environments and the effect of ABA, the relative gene expression of catalase 2 (CAT2) gene was found to play an important role in the enhancement of the chilling tolerance of Trichosanthes kirilowii leaves.

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  Objective: Electro-magnetic radiation (EMR) is emitted from mobile phones. Various researches have shown relationships between mobile phone EMR exposure to cancer and neurologic damages. This study aims to investigate the effects of mobile phone EMR on brain antioxidant enzyme activity and the learning process. Methods: Rat pups and their dames were exposed to EMR for 3 h per day from P2 to P14. After separation of male and female rats on P22, the rats were housed in an air room under normal animal conditions. From P59 to P61, male rats were trained three times per day for a total of 3 days. On P62, their behavior was assessed. The rats were sacrificed by decapitation and the levels of superoxide dismutase and catalase in their brains were assessed. Results: The amount of time to locate the hidden platform and time spent exhibiting freezing behavior increased in exposed group compared to the control group. Superoxide dismutase and catalase activities were reduced in the mobile phone group. Conclusion: Additional studies are necessary to clarify the relationship between mobile phone radiation and brain tissue with regards to antioxidant enzyme activities, learning and memory. Our results suggest that mobile phone radiation may lead to decreased learning that is induced by abnormalities in antioxidant enzyme activities.

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Selenium is an essential element for humans, therefore, adding it to plants is convenient for biofortification. Thus, the aim of this work was to analyze experimentally the ability of sodium selenite to increase the concentration of Se and modify the antioxidant activity in tomato plants. We used plants of the Toro hybrid variety and applied three treatments: 0, 2 and 5 mg L^-1 of selenium as sodium selenite (Na₂SeO₃) using an irrigation system. Three samplings 40, 80, and 120 days after transplantation and a quantification of the accumulation of selenium and macronutrients in leaves, stems, and fruits were carried out. Plant height, stem diameter, firmness, and total solids of fruits and total dry matter were measured. The enzyme activity of catalase, glutathione peroxidase, and superoxide dismutase was quantified. The results indicated positive effects of Se on agronomic variables of the plants and fruit quality; however, fruit production showed no significant differences. Se had no effect on the concentration of the macro and micronutrients. The addition of 5 mg L^-1 of Se resulted in significant increases in the concentration of selenium on a dry basis, reaching 20.4 µg g^-1 in leaves, 52.3 µg g^-1 in stems, and 35.8 µg g^-1 in fruits. The increase in enzyme activity in the fruits was enhanced by the application of 5 mg L^-1 of Se: There was up to 352.7% more catalase activity, 312.2% more glutathione peroxidase activity, and 200.8% more superoxide dismutase activity compared with the control.

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 Sorghum [Sorghum bicolor (L.) Moench] is moderately tolerant to salinity and it is important as a candidate crop for both fodder and grain in salt-affected areas. This pot experiment was conducted at Research Greenhouse of College of Agriculture, Shiraz University, Iran, to evaluate the relative effectiveness of biochemical traits and stress tolerance indices contributing to genotypic differences in salinity tolerance in 30 lines and 14 cultivars of sorghum. In addition, a new indicator, Storage Factor Index (SFI), was defined and used to quantify the Na⁺ partitioning between shoot and root. Among the indices, stress tolerance index was found useful as a selection criterion. Furthermore, the tolerant genotypes had higher K⁺/Na⁺ ratio in shoot and root with greater SFI, indicating that most of Na⁺ was stored in their roots. Although peroxidase and superoxide dismutase were enhanced under salinity conditions in both sensitive and tolerant genotypes, only Catalase (CAT) activity was found to be promoted in tolerant lines/cultivars. Proline accumulation did not appear to be related to salinity tolerance in sorghum lines/cultivars. Overall, our findings suggested that salinity tolerance in sorghum genotypes was not only associated with Na⁺ exclusion from the shoot, but also with the enhancement of CAT activity.

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In recent years, the use of natural and healthy compounds has been considered as a new method to control chilling and maintain postharvest quality of horticultural products. In this study, for the first time, pomegranate fruits were immersed in L-arginine solution at concentrations of 0, 1 and 2 mM and Its effects on the quality of pomegranate fruits ‘Malas-e-Saveh’ grown in Sari region was evaluated during 120 days in cold storage. Based on the obtained results, the treatment significantly increased the total phenol and antioxidant properties of the fruit compared to the control. Fruits treated with 1 mM L-arginine showed more antioxidant activity compared to the control. Moreover, the activity of antioxidant enzymes (CAT, SOD, APX) as well as PAL enzyme increased accordingly. Whereas, H₂O₂ accumulation and PPO enzyme activity in fruits treated with 1 mM L-arginine were significantly reduced. Based on our results, L-arginine treatment can be used as a useful and practical method to maintain nutritional quality and increase the pomegranate storability due to its safety and effectiveness.

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Ambient temperature directly affects growth and development of rice (Oryza sativa L.), especially at the seedling stage. This study aimed to determine the effects of temperature and potassium Chloride (KCl) on certain physiological and biochemical indicators at the seedling stage of two improved rice cultivars (CR203 and DT10). Under the influence of low temperature (10°C), degradation of carbohydrates in seeds was inhibited and the total organic acid content and α-amylase activity decreased, resulting in higher starch content and lower reducing sugar content in both rice cultivars, compared to treatment at the optimal temperature (28°C). For seeds treated with KCl, the α-amylase activity and total organic acid content of the two rice cultivars increased; therefore, the reducing sugar content increased while the starch content decreased. The peroxidase and catalase activities of CR203 decreased under a low-temperature treatment, while those of DT10 increased under the same conditions. Meanwhile, treating seeds with KCl increased the peroxidase and catalase activities of both rice cultivars; however, the peroxidase activity of DT10 increased slightly. The results also suggest that low temperature inhibits the physiological activities of CR203 and DT10 at the seedling stage, while treatment of seeds with KCl increases the physiological activities of both rice cultivars. These results suggest that treating seeds with KCl contributed to improve the tolerance to low temperature stress of the CR203 and DT10 rice cultivars at the seedling stage. In general, treatment of rice seeds with KCl could be recommended to increase cold tolerance at the seedling stage.

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