ساناز رمضانپور

Cold stress is one of the most important factors limiting the early cultivation of most crops, including corn. Cold causes oxidative stress through the production of reactive oxygen species (ROS) in plants. This study was conducted in order to investigate the expression pattern of some genes involved in the response to cold stress (catalase, superoxide dismutase and metallothionein) in corn plants.

This experiment was conducted as a factorial in the form of a randomized complete block design with four replications and with three varieties of corn singlecross 260, singlecross 302 and doublecross 370. Planting was done in pots with a capacity of 4 kg of soil. qPCR technique was used to check gene expression pattern.

The results of the analysis of the gene expression pattern showed that among the examined cultivars, singlecross 260 had the highest expression of catalase and superoxide dismutase genes, and singlecross 302 had the lowest expression of these genes. Examining the metallothionein gene expression pattern also showed that the expression level of this gene is the lowest in singlecross 260 and the highest in singlecross 302. The high expression of metallothionein gene in singlecross 302 is probably due to the occurrence of oxidative stress due to cold stress, accumulation of hydrogen peroxide and low expression of catalase gene. Also, growth indices including germination percentage, germination speed, leaf surface and chlorophyll a and b showed a good correlation with the expression level of catalase and superoxide dismutase genes.

Singlecross 260 and Singlecross 302 had the highest and lowest levels of expression of superoxide dismutase and catalase genes, germination percentage, germination speed, leaf area and chlorophyll, respectively. The activity of antioxidant genes such as catalase and superoxide dismutase prevent the reduction of chlorophyll and damage to the plant's photosynthetic apparatus.

Potato (solanum tubrusum) is the fourth staple food after rice, wheat and corn. It is the most important tuberous crop. Potato color flesh is one of the most important parameters in food industry and marketability. The flesh color of the tetraploid cultivars range from white to cream and yellow to dark yellow. There are a few cultivars with red or blue/pink flesh color. Based on mutant clones containing superior quantitative and qualitative traits and flesh color change in Caesar potato variety, this research was carried out with the aim of determination of the reason of color flesh change in Caesar mutant.

Mutant and parent (Caesar) clone were cultivated in research farm of Ardabil Agriculture Research Center in 1397. Sampling was done in 4 replications for each clone. Changes in total carotenoid and its components were performed by spectroscopy-UV and HPLC-chromatography, respectively.

Carotenoid content in mutant clone was 319.54(µg/100 FW) and in parent clone was 246.36 (µg/100 FW). This result showed that content of total carotenoid in mutant was 1.3 times the carotenoid content of the parent. HPLC results showed that Lutein content was increased in mutant in comparison to parent, whereas, violaxantin was higher in parent that mutant clone.

Based on our results total carotenoid content along with lutein play an important role in potato color flesh change. Our finding is in accordance with results of other researches that showed that flesh color change from cream (parent) to yellow (mutant) was affected by total carotenoid content generally and lutein specifically.

Salinity is one of the most important growth limiting factors and rice production in arid and semi-arid regions of the world. In order to investigate the effect of salinity stress on biochemical characteristics and the expression of some inducible genes in the seedling stage of rice, an experiment in the form of chopped plots with a basic design of randomized complete blocks were performed with four replications. The main factor included five levels of zero (control), 50, 100, 150 and 200 mM sodium chloride to create salinity stress. Salinity levels were applied along with Yoshida's nutrient solution in a hydroponic system. The sub-factor included four varieties of rice (Kashuri, Shiroodi, Tarem and Kohsar). In this research, the cellular oxidation level index (TBARM), enzyme activities and expression of some important antioxidant genes, including catalase, superoxide dismutase, ascorbic peroxidase, and the TCTP transcription factor, were investigated. The results of the variance analysis of the data showed that the difference between cultivars and salinity levels for all studied traits was significant at the probability level of 1%. Also, by increasing the salinity level, the activity of the studied enzymes and the expression of catalase, superoxide dismutase, ascorbic peroxidase and TCTP genes increased. According to the obtained results, Shiroudi and Kohsar cultivars were identified as salinity tolerant cultivars.

Iimportance of Salicornia as a halophyte plant is the ability to grow in saline and irrigated areas with unusual and highly saline water. In order to investigate the effect of phytohormones on salinity adjustment on vegetative and physiological traits of Salicornia europaea L., an experiment was conducted in a greenhouse located in Gorgan city. The experiment was conducted as a factorial experiment in a completely randomized design with three replications. The first factor was different salinity levels (0, 400 and 600 mM), the second factor was hormone treatment (without hormone, 50 mM abscisic acid, 50 mM melatonin, and the combined effect of both hormones) on aerial spraying. Interaction of salinity and hormones on shoot height, branch number, shoot and root wet weight, seed weight, spike dry weight, total shoot dry weight of Salicornia at one percent (P <0.01) and shoot height and ion leakage (LE) were significant at the five percent level (P <0.05). The maximum yield, grain weight, spike dry weight and total shoot dry weight were increased by 110 (1.1 fold), 195 (19.5 fold) and 245 (24.5 fold) percent, respectively, in 400 mM salinity and abscisic acid and melatonin, together, were obtained. The most of the studied traits were obtained at 400 mM salinity with the combined effect of abscisic acid and melatonin. in the correlation coefficients, straw fresh weight trait coefficients with straw dry weight and root fresh weight at level one percent (P˂0.01) and number of branches, spike dry weight and grain weight at level five percent (P <0.05). The root fresh weight trait was positively and significantly correlated with number of branches, spike dry weight, grain weight and straw dry weight at level five percent (P <0.05). foliar application of abscisic acid and melatonin can help the plant to tolerate salinity and increase its functional properties (especially melatonin in yield components) will be helpful.

Drought is one of the most important abiotic stresses in agriculture, which limit crops production. Drought tolerance is a complicated trait that is controlled by polygenes, which is expresses the difficulty of breeding of drought tolerance. Variety of strategies has been used to improve this trait in crops, including traditional selection methods and genetic engineering. In this case, irradiation is an appropriate approach for improving the level of genetic variation in a short time. Many studies show that the expression of most genes in environmentally variable conditions is based on the combination control of several transcription factors and their binding to the elements in the promoter. Therefore sequencing of one of the genes involved in the degradation of proteins (26Sp7) using genome sequencing, sequencing of promoter using NEW PLACE and plantCARE software, And the expression pattern 26Sp7 in mutant line T-65-58-8 (semi-drought tolerant) derived from Tabasi (drought-sensitive) radiated with gamma rays in seedling stage during drought stress by QRT-PCR were studid. The expression of the 26Sp7 in Tabasi and mutant showed an increase in all stress treatments. So, in the mutant line, it has peaked in 3 hours after start of stress. On the other hand, in Tabasi, with the onset of drought stress, the expression of this gene increased, until it reached maximum in 48 hours after stress. The expression in the Tabasi showed an increase in gene expression in all stress treatments, which in turn probably indicates the destruction of proteins in drought stress treatments, which also verified the sensitivity of this variety. on the other hand, the promoter sequences of this gene indicate regulatory elements during drought stress such as dehydration responsive elements (DRE) and the binding site of MYB and MYC proteins and abcisic acid responsive elements (ABRE) and responded to light (GT) and gene transcription regulator elements such as the TATA box and the CAAT box. Thus, the increased expression of this gene during drought stress may be attributed to the binding sites of transcription factors that cause this gene expression during drought.

Barley (Hordeumvulgare L.) is one of the most important cereals in the world which is used as human and cattle feed and for malt production. One of the most important steps in a hybrid and selection breeding program of barley is the selection of suitable parents with high general (GCA) and specific combining ability (SCA) for grain yield. In order to estimate the combining ability and heterosis in barley for a number of qualitative traits, seven genotypes were crossed in one-way diallel crosses using Griffing (Method II). Grain number per spike, grain weight per spike, spike weight, 1000-grain weight, number of spikelet, plant height, spike length, peduncle length, days to physiological maturity, and spikelet density were measured. Results of variance analysis showed that there were very significant differences between genotypes for all the measured traits. General combining ability (GCA) effect was significant for all traits, 166/352 genotype had the highest value of GCA for grain number per spike (4.757), grain weight per spike (0.245), spike weight (0.378) traits, whereas Specific combining ability (SCA) effect was significant for all traits except for plant height, days to physiologic maturity, and spikelet density. Three crosses 67/110×283/352, 95/110×216/352 and Sahra×216/352 showed the highest values of SCA for grain number per spike (7.704), grain weight per spike (0.371) and 1000-grain weight (8.619), respectively. Moreover, dominance variance was the most effective factor in genetic control of traits. Three crosses 216/352×283/352, 104/110×216/352 and Sahra×216/352 showed the highest values of heterosis for grain number per spike (4.95), grain weight per spike (44.13) and 1000-grain weight (31.6), respectively. Maximum and minimum broad sense heritability was obtained in the number of grains per spike (87/7%) and spike density (47/36%) respectively. Lowest and highest narrow sense heritability was obtained for peduncle length (15/72%) and weight of grains per spike (50/5%), respectively. Estimates of SCA showed that 95/110×216/352, such as 67/110×283/352 crosses could be used in breeding programs to release cultivar to increase yield-related traits.

Soybean is a diploid plant with relatively wide range of environmental conditions and climate adaptation. Water deficit is first limitation that cause soybean yield reduction in dried and semi-dried regions. In addition to the physiological changes that occurs due to water deficiency in plants, oxidative damage is also an important factor limiting plant growth and production. In this study, the level of super-oxide and hydrogen peroxide were measured, also the amount (of) super-oxide dismutase and catalase enzyme as well as ascorbic acid, α-tochopheroll, cartenoid and TBARM (cellular oxidative level) were assessed. Three soybean genotyps (DPX, sari and WE6 Line) were evaluated for above traits in three drought stress treatments included 50mm evaporation (as control), 100mm and 150mm evaporation from A class evaporation pot. Leaf samples collected for each treatments in three reproductive stages (flowering, pod elongation and seed filling). The variance analysis results showed that drought stress treatment had significant effect on all measured traits. Base on this, enzyme activity (super oxide and catalase) and non-enzymatic antioxidants (ascorbic acid, carotenoid and α-tocopherol) had a key role in response to drought stress in studied soybean genotypes. DPX cultivar and WE6 line showed superior antioxidant agents activity in comparison with sari cultivar in drought stress conditions.

Drought stress is one of the important factors that restrict crop production in tropical and semi-tropical areas. This experiment has taken place in Golestan province Agriculture research station in split plot format with RCBD design with four replicates. Drought stress as a main factor included three levels (irrigation after 50، 100، and 150 millimeters evaporation from the A class evaporation pot) of which 50 millimeters evaporation is considered as control. The sub factor included factorial combination of 3 varieties (DPX، Sari and WE6) and three sampling stages (flowering، packing pod and grain filling). Evaluated traits included A and B chlorophyll amount and alternation in gene expression. The amount of chlorophyll was increased on first step of the stress condition (100 ml evaporation) and decreased again، on the second step (150 ml evaporation). The TBARM level was increased under the stress condition as well as growth stages. The gene expression analysis was carried out by using QRT-PCR technique. The results showed at first level of drought stress condition catalase gene expression had the most amounts. It was quite similar to DREB1 gene expression. DPX variety showed the most DREB1 gene expression first level of drought stress condition in packing pod stage، and least reduction in second level of the drought stress condition. Sari variety showed the most reduction in DREB1 gene expression in second level of the drought stress condition. Chlorophyll amount also showed a positive correlation with the catalase and DREB1 genes expression.

Deoxynivalenol (DON) is a major mycotoxin produced by the fungus Fusarium graminearum during infection and is known to be harmful to both animal and human health. DON is believed to act as a virulence factor in fungal pathogenesis by inhibiting eukaryotic protein synthesis. The putative site of action of DON is 60s ribosomal protein L3 (RPL3). Previously, single amino acid changes in RPL3 conferring DON resistance have been described in yeast. Sequence characterization of six wheat genes encoding RPL3 has shown that there is no amino acid alteration between resistant and susceptible cultivars. The main goal of this study, was to determine any induced changes in transcriptional levels of RPL3 (A and B type) genes under stress conditions caused by Fusarium Head Blight (FHB) in wheat. In order to detect expression levels of RPL3 genes, we extracted RNA from both inoculated and non-inoculated spikes of sensitive and tolerant cultivars, during 1, 3 and 7 days post-infection. Quantitative RT-PCRs were performed with A and B type-specific RPL3 primers to detect the expression differences. Primary data indicated a decrease in the genes expression level in Sumai3 and Falat cultivars 24 hours post-infection. On the other hand, increased level of RPL3A transcript in Frontana 7 days post-infection may reveal the role of this specific protein in inducing the resistance in this cultivar.