Research Paper
Genetic engineering & plant breeding
Mohammad Sadegh Taghizadeh; Mohammad Mehdi Sohani; Reaz Shirzadian-Khoramabad
Abstract
Only a few low molecular weight signals, including jasmonic acid (JA), salicylic acid (SA), and ethylene (ET), regulate the expression of a group of defense-related genes in the plants. The expression of plant defense genes is stopped against aggressive agents using these regulators, and in some cases, ...
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Only a few low molecular weight signals, including jasmonic acid (JA), salicylic acid (SA), and ethylene (ET), regulate the expression of a group of defense-related genes in the plants. The expression of plant defense genes is stopped against aggressive agents using these regulators, and in some cases, may be able to destroy or strengthen the defense signaling pathways of the plant for their purposes. In this study, the acetosyringone was used to study virulence genes induction in Agrobacterium tumefaciens A348 (MX311) and A348 (MX243) at three levels of 0, 100, and 200 μM. Subsequently, a concentration of this, which induced virulence genes highly, was selected to transform the Arabidopsis mutants using Agrobacterium tumefaciens EHA105. The results showed that the highest expression of virD2 and virB2 was at the levels of 200 and 0 μM of acetosyringone, respectively. Besides, the transformation results showed that the highest and lowest transformation efficiency was in the SA mutants (nahG) and the control plants (Col-0), respectively. Therefore, since the SA-suppression mutants have the highest transformation efficiency compared to others, it can be concluded that the SA may play more role in plant defense against pathogens than two other hormones. Hence, increasing the efficiency of gene transfer in these mutants will open the way for the expression and production of higher amounts of recombinant protein in these mutants compared to the wild type.
Research Paper
Plant breeding for abiotic & biotic stresses
Hamid Valizadeh; Saeid Navabpour; Ali Dehestani; Pooyan Mehraban
Abstract
Drought stress is one of the most important factors limiting the growth and production of crops. Exogenous application of some biological or chemical agents can mitigate the negative effects of drought stress. In this experiment, the effect of hydrogen peroxide application on water-stressed corn plants ...
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Drought stress is one of the most important factors limiting the growth and production of crops. Exogenous application of some biological or chemical agents can mitigate the negative effects of drought stress. In this experiment, the effect of hydrogen peroxide application on water-stressed corn plants was investigated through various biochemical and molecular methods. Corn seedlings grown in hydroponic culture were treated with hydrogen peroxide (2 mM) and then exposed to water stress using polyethylene glycol 6000 at 3 levels of 0, -2 bar and -4 bar. The results showed that drought stress altered all of the studied traits significantly. With increase in stress level, the activity of catalase enzyme was decreased and the highest drop was of 50% was on the eighth day post stress. It was revealed that catalase activity was increased up to 18% on the second day after the stress and it decreased significantly with the time. The indigenous accumulation of hydrogen peroxide increased significantly in -4 treatment and four days after stress while it was reduced by 50% on the eighth day after stress. It was revealed that hydrogen peroxide application increased PAO gene expression 1.7 times compared to the control plants. Its expression was decreased by 35% at -4 bar in control plants while hydrogen peroxide treatment increased its expression by 2.8 times. These results increase the plant's resistance to drought stress and reduce the negative effects of drought stress. In this way, it reduces the negative effects of drought stress.
Research Paper
Germplasm genetic diversity & plant breeding
Ayman Ebrahim Badran; Rasha M. Khalil; Ehab Mostafa
Abstract
In the context of the increasing demand for cultivation of marginal lands affected by salinity, it became necessary to assess the most important crop traits that can be relied upon as well as to identify genotypes that have the potential to withstand adverse environmental conditions. In this study ten ...
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In the context of the increasing demand for cultivation of marginal lands affected by salinity, it became necessary to assess the most important crop traits that can be relied upon as well as to identify genotypes that have the potential to withstand adverse environmental conditions. In this study ten genotypes of safflower crop were evaluated under two salinity levels during two successful agricultural seasons. According to correlation and path coefficient analysis and positive direct effect of studied traits, 100 seed weight followed by No. of capitulum / plant in related to seed yield. Also, the results confirmed based on tolerance indices to salt stress, that Line 6 was followed by local cultivar recorded the highest values as an indicator of tolerance. Protein analyses were conducted to identify protein markers associated with salinity tolerance for selection of promising Lines tolerant to salt stress. This investigation revealed high polymorphism with protein markers that could be useful tools to assist breeders in the selection and breeding of safflower Lines tolerant to salinity stress. Therefore, plant breeders can take advantage of these various parameters to design successful breeding program under conditions of salt stress.
Research Paper
Plant breeding for abiotic & biotic stresses
Morteza Barati; mohammad reza azimi; Mohammad Reza Naghavi; Ehsan Mohsenifard
Abstract
MicroRNAs (miRNAs) are small RNAs of about 22 nucleotides. They are commonly known for their essential roles in regulating biotic and abiotic stress response in plants. Drought stress is one of the most common problems for wheat (Triticum aestivum L.) productivity in Iran. The present study evaluated ...
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MicroRNAs (miRNAs) are small RNAs of about 22 nucleotides. They are commonly known for their essential roles in regulating biotic and abiotic stress response in plants. Drought stress is one of the most common problems for wheat (Triticum aestivum L.) productivity in Iran. The present study evaluated the expression of miR9863a and its drought-related target genes (PLGG1 and SAR1A) in wheat and three Aegilops species under drought stress. Drought stress was induced by limiting the irrigation, maintaining the soil moisture at 20% field capacity for 14 days, followed by 3 days without water supply. The results showed the differently expression of miR9863a in the shoot of the studied plants under drought stress condition, so that its expression was increased in Ae. tauschii and Ae. crassa and decreased in Ae. cylindrica. This difference expression could be due to the mixing of RNAs of different tissues of shoots or the nature of miRNA as a mediator molecule in various biological processes. By considering the expression pattern of miR9863a and its target genes in Ae. tauschii, it could be attributed to the effect of miR9863a in response to drought stress by PLGG1 through its role in glycerate/glycolate transfers and SAR1A through the role of trafficking of transcription factors from the endoplasmic reticulum to the nucleus. Also, as a complement to previous studies on the role of miR9863 in countering plant diseases, the results herein demonstrated how this miRNA assists the abiotic stress-response mechanism in plants, with an emphasis on drought stress.
Research Paper
Genetic engineering & plant breeding
Mahmood Khosrowshahli; Elham Ansari; Ali Ashraf Jafari; Ali Etminan
Abstract
The comet assay is a sensitive test for detecting DNA damages used as an instrument to compare the intensity of the genotoxic effects of colchicine. The Pattern and the index value of three parameters of comet assay (tail length, tail intensity, tail moment) were compared among the autotetraploids produced ...
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The comet assay is a sensitive test for detecting DNA damages used as an instrument to compare the intensity of the genotoxic effects of colchicine. The Pattern and the index value of three parameters of comet assay (tail length, tail intensity, tail moment) were compared among the autotetraploids produced from three populations of diploid cross pollinated Medicago sativa spp. Caerulea and autotetraploid populations from five diploid self pollinated species by treatment with three concentrations of colchicine (0.1, 0.5, and 1%) and five alfalfa cultivars. Results have shown the same level of increases and pattern in the parameters of comet "among the induced tetraploids from the two categories of medics" in the concentration of 0.1 and 0.5% of colchicine. Also increasing colchicine concentration from 0.1 to 0.5% resulted in a more pronounced augmentation of comet parameters. Induced tetraploids resulted from the two mentioned colchicine concentrations showed increases in the value of the three comet parameters compared to the cultivated alfalfa cultivars and two diploid categories medic species so the pattern of parameters were not similar. At the concentration of 1% of colchicine, only two annual species produced tetraploids showing very pronounced augmentation of comet parameters in comparison with 0.1 and 0.5% colchicine concentrations. Changes in patterns and values of the three parameters in induced tetraploids compared to cultivated alfalfa and diploid medic species demonstrate differential effects of damages of colchicine from one concentration to another, then a new variability in each concentration change will be created.
Research Paper
Genetic engineering & plant breeding
Morteza Noryan; Islam Majidi Harvan; hossein sabouri; Farokh Darvish Kojouri
Abstract
To evaluation of the genetic structure of drought tolerance in rice, an experiment was conducted using 120 RILs in a randomized complete block design with three replications in Gonbad Kavous University. 16 and 20 QTLs were identified at vegetative and reproductive stages, respectively. The correlation ...
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To evaluation of the genetic structure of drought tolerance in rice, an experiment was conducted using 120 RILs in a randomized complete block design with three replications in Gonbad Kavous University. 16 and 20 QTLs were identified at vegetative and reproductive stages, respectively. The correlation variance analysis results indicated a significant relationship between traits under normal and drought stress conditions at the two growth stages. At the vegetative stage, this significant difference was recorded in all studies traits, except for plant height, at the 1% level, suggesting the diversity of the analyzed lines for the measured traits. In a comparison of the three evaluated treatments, the qRN-12, qRS-11, and qRV-12 lines were determined as stable QTLs appropriate for a selection of drought-tolerant and drought-sensitive lines at the vegetative stage in different conditions. At the reproductive stage, the highest correlation coefficient was obtained in the panicle length from the comparison of traits in flooded and drought stress conditions. Several new alleles of drought-tolerant QTLs identified in this study. In two environmental conditions, the important detected QTLs, such as qNTF-12 and qNL-3, belonged to the numbers of fertile tillers and leaves, determined as stable QTLs at the reproductive stage. Most of the traits were identified on the rice chromosome 12 and its genomic regions. In this study, the QTLs identified at vegetative and reproductive stages can be used as stable and major QTLs for the selection of drought-tolerant and drought-sensitive lines at all plant growth stages using marker-assisted selection in the rice.
Research Paper
Plant breeding for abiotic & biotic stresses
Elham Younesi-Melerdi
Abstract
The WRKY transcription factors (TFs) family is one of the largest plant-specific TFs families that play a key role in mediating pathways of stress response. In current study, an overview analysis was performed on Arabidopsis WRKY TF family members that their differential expression (DE) under various ...
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The WRKY transcription factors (TFs) family is one of the largest plant-specific TFs families that play a key role in mediating pathways of stress response. In current study, an overview analysis was performed on Arabidopsis WRKY TF family members that their differential expression (DE) under various stresses was reported in GEOprofile database. First, WRKY members with DE were extracted from GEOprofile and information of the data set, sequence and their gene structure were obtained. Then, the concept of the intersection of sets was used to selection some of WRKY TFs for downstream analysis. DE of candidate members was compared by t-test. The protein – protein interaction network were predicted by STRING web server. A total of 16 WRKY genes were identified in the 11 dataset of GEOprofile. The sequence information showed that WRKY75 and WRKY33 have the minimum and maximum length of the amino acid sequence, respectively. Analysis of the gene structure showed that 56% of the studied WRKY genes have 3 exons and all 16 members are distributed in all five chromosomes of Arabidopsis. Also, the results showed that four WRKYs including WRKY40, WRKY46, WRKY18 and WRKY33 were most frequent at response to various stresses. The protein-protein interaction network showed that WRKY40, WRKY46, WRKY18 and WRKY70 have high interaction with four genes of MPK4, ACS6, MKS1 and STZ. Therefore, WRKY40, WRKY46, WRKY18 and WRKY33 can be the most important WRKY TFs of Arabidopsis at response to various stresses and can be used in genetic and metabolic engineering projects.
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