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.
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.
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.
Plant breeding for abiotic & biotic stresses
Tayebeh Roshankar; Zahra Movahedi; Naser Sabaghnia
Abstract
Salinity stress effect especially the highest concentration (2 dS m-2), was significant for all traits including plant height (PH), number of flowering branches (NFB), number of leaves per plant (NLP), stem diameter (SD), fresh shoot weight (FSW), fresh root weight (FRW), dry shoot weight (DSW), dry ...
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Salinity stress effect especially the highest concentration (2 dS m-2), was significant for all traits including plant height (PH), number of flowering branches (NFB), number of leaves per plant (NLP), stem diameter (SD), fresh shoot weight (FSW), fresh root weight (FRW), dry shoot weight (DSW), dry root weight (DRW), root length (RL), number of hairy roots (NHR), number of main roots (NMR), root diameter (RD), total chlorophyll content (TCC), chlorophyll a (Cha), chlorophyll b (Chb), carotenoid content (CC), root sodium content (RSC), leaf sodium content (LSC), leaf potassium content (LPC), protein amount (PA), proline magnitude (PM), peroxidase (POD), catalase (CAT)and decreasedthe measured traits compared to the control. NaCl at 2 dS m-2 induced- salinity reduced the number of leaves per plant by 43.58% compared to the control. The highest number of hairy roots (19.78) was observed in salinity treatment with 0.25 dS m-2, which was accompanied by a significant decrease with increasing sodium chloride concentration to 2 dS m-2. The total leaf protein content, proline accumulation and antioxidant activity of catalase and peroxidase at the highest salt concentration (2 dS m-2) showed a significant increase compared to control. The results of this experiment indicate that the tolerance of the herbaceous medicinal plant to salt stress is induced by increasing the accumulation of proline, soluble proteins and antioxidant enzymes activity.
Plant breeding for abiotic & biotic stresses
Mehdi Safaeizadeh
Abstract
In plant innate immunity, the first line of defense against microbial pathogens is triggered by the perception of molecular signatures of the pathogens, by a highly sensitive membrane resident immune receptors. These pathogen-associated molecular patterns (PAMPs) are perceived by pattern-recognition ...
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In plant innate immunity, the first line of defense against microbial pathogens is triggered by the perception of molecular signatures of the pathogens, by a highly sensitive membrane resident immune receptors. These pathogen-associated molecular patterns (PAMPs) are perceived by pattern-recognition receptors (PRRs) of the host to initiate pattern-triggered immunity (PTI). The endogenous plant signals, which are called damage-associated molecular patterns (DAMPs), are generated under different circumstances such as wounding, biotic and abiotic stresses. The DAMPs can activate the PTI and subsequently trigger the immune system in plants. These peptide signals called plant elicitor peptides (Peps) first discovered in Arabidopsis thaliana and later their orthologues were identified in different plant species. Peps are involved in immunity against diverse biotic and abiotic stresses and can fine-tune immune signaling pathways. So far, eight endogenous signals (AtPep1 to AtPep8) are discovered in the model plant A. thaliana. Recent studies revealed that the Pep members are not redundant and each of them has a specific function. AtPeps-triggered immunity is emerging as a highly complex, dynamic and a coordinated process involved in immune signaling cascades and consequently induces adequate defense responses. Therefore, it is possible to apply synthetic Peps to induce the immune system against microbial infections in plants. Here, the recent researches and progresses on Pep-triggered signaling are presented from their first discovery until now. Furthermore, the finding of their corresponding receptors AtPEPR1 and AtPEPR2 is explained in detail. Moreover, the subsequent events in the cells as the consequence of AtPeps perception are highlighted.
Plant breeding for abiotic & biotic stresses
Ali Hedayati; Mohammad Abdoli
Abstract
The present study investigated the effect of 14 treatments consisting yeast extract (YE) (0, 0.5, 1.0, 1.5, 2 g/l), salicylic acid (SA) (0, 40, 80, 160, 320 mg/l) and YE (1 and 1.5 g/l) in combination with SA (80 and 160 mg/l) foliar application on essential oil content and constituents of lemon balm ...
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The present study investigated the effect of 14 treatments consisting yeast extract (YE) (0, 0.5, 1.0, 1.5, 2 g/l), salicylic acid (SA) (0, 40, 80, 160, 320 mg/l) and YE (1 and 1.5 g/l) in combination with SA (80 and 160 mg/l) foliar application on essential oil content and constituents of lemon balm (Melissa officinalis L.). The experiment was conducted in a completely randomized design with three replications under greenhouse conditions. Essential oils analyzed by GC/MS and a total of 39 compounds were identified that the major constituents were citronellol, trans-carveol, γ-3-carene, linalool, citral and carvacrol acetate, respectively (42.8 to 48.0% in total). Citronellol was the main constituent of essential oils with 11.05%. SA and YE significantly altered the amount of 23 constituents of lemon balm essential oil (P˂0.01). The highest citronellol, linalool and citral (14.50, 7.9 and 8%, respectively) production was obtained at 1.5 g/l YE+160 mg/l SA treated plants that was 103, 88 and 203% higher than control plants, respectively. The highest essential oil content (0.336% v/w) that was 49% higher than control was achieved by 1.0 and 1.5g/l YE+160 mg/l SA treatments. The principal component analysis (PCA) and heatmap indicated that the content of compounds varied with different treatment and also revealed a clear separation between control and treatment groups. The results suggested that SA, YE and SA in combination with YE has considerable ability to stimulate the production of major constituent such as citronellol, citral, and linalool in the lemon balm.
Plant breeding for abiotic & biotic stresses
Masoud Fakhrfeshani; Ali Niazi; Fatemeh Keykha akhar; Pedram Assar; Leila Taghipour
Abstract
There is an imbalance between increase rate in demand for agricultural products and the growth rate of agricultural production. Much of this production deficit is attributed to abiotic stresses. These stresses reduce the yield of crops by more than 50%. Obviously, it worth studying any idea which may ...
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There is an imbalance between increase rate in demand for agricultural products and the growth rate of agricultural production. Much of this production deficit is attributed to abiotic stresses. These stresses reduce the yield of crops by more than 50%. Obviously, it worth studying any idea which may lead to reducing the damages of them. In the present research, the transcription level of Catalase in root and shoot of Oryza sativa var. IR64 and Aeluropus littoralis using qtr.PCR and the Aromatic and Instability indices based on amino acid composition were evaluated. The samples were taken at short-term, mid-term and long-term stress span. Analysis of the results showed significant differences in the both gene expression and studied biochemical aspects. The expression of catalase gene in Aeluropus roots was periodic and showed a twice increase and then a decrease however in roots of rice there was just a rise in its expression. In the all sampling of the rice shoots, CAT gene expression levels were either lower or without any significant different in contrast to the control samples. Meanwhile, the rates of expression in most of stressed Aeluropus shoots were significantly higher than control samples. Comparison of the biochemical indices showed that Aeluropus has a relative superiority over rice in terms of amino acid sequences. Based on the evaluated indices, the differences of response to salinity stress in the studied plants could be attributed to the differences in the promoter and nucleotide sequences of their genes.
Plant breeding for abiotic & biotic stresses
Fariba Morsali Aghajari; Reza Darvishzadeh; Mitra Razi
Abstract
Salinity is one of the most important non-biological stresses that affect plant growth and development. Effect of different levels of NaCl (0, 2, 4, 6 and 8 dS/m) were investigated on enzymatic and non-enzymatic activities in C64 and C68 oilseed sunflower genotypes at two times; 3 and 12 days after salinity ...
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Salinity is one of the most important non-biological stresses that affect plant growth and development. Effect of different levels of NaCl (0, 2, 4, 6 and 8 dS/m) were investigated on enzymatic and non-enzymatic activities in C64 and C68 oilseed sunflower genotypes at two times; 3 and 12 days after salinity stress application. Net photosynthesis rate, chlorophyll content and soluble proteins amount decreased by increasing salinity level but proline and malondialdehyde (MDA) contents increased. However, the changes in net photosynthesis in the two studied genotypes was different across time and do not follow statistically the same trend line. In genotype C86, the reduction of photosynthesis rate at all studied salinity levels was very high compared to normal condition (0 dS/m) after 3 days; especially at salinity levels of 2, 4 and 6 dS/m, while 12 days later, the decrease of photosynthesis rate was moderate at salinity levels of 2 and 4 dS/m but severe at 6 and 8 dS/m salinity levels. The highest amount of proline (31.36%) related to tolerant genotype and the lowest amount (7.72%) related to susceptible one was measured 12 days after 2 dS/m salt stress treatment. Considerable MDA was observed in both tolerant and sensitive genotypes 12 days post salt stress application; the highest amount (83%) was observed at 8 dS/m treatment. Catalase and ascorbate peroxidase activity increased with increasing salt intensity. The rate of increase in guaiacol peroxidase activity was higher in C86 genotype than C64. Chlorophyll a and total chlorophyll contents decreased in both sunflower genotypes under salinity stress. The lowest amount of total chlorophyll (8.6%) was observed in the salinity level of 8 dS/m in the sensitive line (C64). Results revealed the C64 and C68 selected genotypes from two our identified sunflower heterotic groups have different physiological response to salinity stress and C68 is more tolerant to salt stress than C64. So, they can be potentially used as parents in sunflower breeding programs to produce salt stress tolerant hybrids.
Plant breeding for abiotic & biotic stresses
Seyedhamidreza Hashemipetroudi; Esmail Bakhshandeh
Abstract
Sesame (Sesamum indicum L.) seed is a rich source of oil and protein, which could be used for cooking or primary source for some industrial applications. Seed germination is the most fundamental stage of a plant’s life cycle, which is significantly influenced by various abiotic stresses. As a first ...
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Sesame (Sesamum indicum L.) seed is a rich source of oil and protein, which could be used for cooking or primary source for some industrial applications. Seed germination is the most fundamental stage of a plant’s life cycle, which is significantly influenced by various abiotic stresses. As a first report, the study attempted to evaluate the effect of environmental factors (i.e., low, optimum and high temperatures (T), water potential (ψ) and salinity) on eight superoxide dismutase (SOD) gene expressions (two Mn-SOD, two Cu/Zn-SOD and four Fe-SOD) during sesame germination. Results showed that all studied treatments remarkably influenced germination characteristics of sesame (P ≤ 0.05). In general, the negative impact of each stress on sesame germination could be ranked as ψ > salt stress > high T > low T, indicating that the germination was more influenced by ψ than salt stress and T. There was a strong association between the decrease in germination parameters (relative to the optimal T) and the decrease in SiSOD expression under various stresses. Our results discovered that the SiSODs expression patterns were stress-specific. However, when subjected to the same stress, the majority of SiSOD genes displayed similar expression patterns. The findings of this study could lead to a better understanding of SOD's role in other plants and the mechanisms involved in plants' stress responses, especially during their early stages of development.
Plant breeding for abiotic & biotic stresses
Peiman Mohit Rabary; Zahra Movahedi; Mehdi Ghabooli; Majid Rostami
Abstract
Salicylic acid (SA) is a phenolic phytohormone that acts as a key regulator of the signaling network in plants under biotic and abiotic stresses. SA exerts stimulatory effects on various physiological processes to plant growth and development. In this research, valerian, chicory, withania, and purple ...
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Salicylic acid (SA) is a phenolic phytohormone that acts as a key regulator of the signaling network in plants under biotic and abiotic stresses. SA exerts stimulatory effects on various physiological processes to plant growth and development. In this research, valerian, chicory, withania, and purple coneflower plants were transferred into an aeroponic system where the effects of SA were investigated on some plant characteristics under greenhouse conditions. The plants were foliar sprayed with SA (0, 50, 100, and 150 mg l-1) at 20, 40, and 60 days after transplanting (DAT). Results showed that the highest chlorophyll a+b, carotenoid, plant height, root length, root volume, number of leaves per plant, root fresh weight, root dry weight, shoot fresh weight, and shoot dry weight were obtained from 150 mg l-1 SA in all the studied medicinal plants. The results revealed that the exogenous application of SA in the aeroponic system increased the root fresh weight, root dry weight, shoot fresh weight and shoot dry weight of chicory, withania, valerian, and purple coneflower plants. Also, the studied medicinal herbs grew well in the aeroponic system.
Plant breeding for abiotic & biotic stresses
Mehdi Ghabooli; Shima Sadat Beheshti Rooy; Ehsan Mohseni fard; Rouhollah Karimi
Abstract
Low temperature is a major abiotic stress which can significantly affect the grape production. microRNAs play an important role in the control of plant development and response to adverse environmental conditions. Although miRNAs and their targets have been identified in several Vitis species, their ...
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Low temperature is a major abiotic stress which can significantly affect the grape production. microRNAs play an important role in the control of plant development and response to adverse environmental conditions. Although miRNAs and their targets have been identified in several Vitis species, their participation during cold accumulation remains largely unknown. One such microRNA is miR395, which is conserved and regulates sulfate assimilation and distribution in plants. In this study, the possible role of miR395 in cold stress response was investigated. Identification of target genes, gene ontology and biological system analysis were performed to identify the major networks in which this miRNA is involved. Finally, the effects of gradual chilling and also a shock chilling on the expression of miR395 were investigated. In total, five target genes were identified, which all of them are targeted by miR395s a to m, whereas of the five target genes, only one is identified by miR395n as a target. Three of these genes, including ATP sulfurylase, sat-1 and, LAST3-like are involved in the control of sulfur metabolism and transport. Pathway analysis showed that miR395 was involved in response to cold stress in grape through cellular response to sulfate and phosphate deficiency. Based on RT-PCR results, contrary expression patterns of miR395 under gradual (up-regulated) and shock chilling stress (down-regulated) were observed. The changes of sulfate assimilation process would influence the formation of sulfur-containing antioxidant compounds. These results provide an insight into the regulatory roles of miR395 in response to low-temperature stress in V. viniferae.
Plant breeding for abiotic & biotic stresses
Nafise Taghizadeh; Gholam Ali Ranjbar; Ghorban Ali Nematzadeh; Mohammad Reza Ramazani Moghaddam
Abstract
Salinity is one of the most important limitation factors in development of agricultural products. Cotton has a relative tolerance to salinity; however, salinity reduces its growth during germination and seedling stages. In this research, split-factorial design of time based on randomized complete block ...
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Salinity is one of the most important limitation factors in development of agricultural products. Cotton has a relative tolerance to salinity; however, salinity reduces its growth during germination and seedling stages. In this research, split-factorial design of time based on randomized complete block design with 3 replications was used. The real-time PCR results for, root, stem, and leaves of 14-day cotton seedlings of tolerant (Sepid) and sensitive (Thermus14) cotton cultivars with salinity levels from 0 to 16 ds.m-1 were analyzed at three time points, namely 0, 7 and 14 days after salinity stress. Selected genes for Real Time PCR reaction in current study were selected using Cytoscape 3.3.0 software. Results showed that the selected genes GhERF2, GhMPK2, GhCIPK6, GbRLK, GhNHX1, GhGST, GhTPS1 and Gh14-3-3 have positively responded to salinity stress and their expression in the root was higher than in stem and leaf. Moreover, the expression of tolerant genotype (Sepid) was higher than the sensitive cultivar (Thermus 14) one, however, a slight increase in sensitive genotypes was observed in a number of genes (GhERF2 and GhGST) 14 days after starting the stress treatment.
Plant breeding for abiotic & biotic stresses
Mahnaz Rahmati; Mohsen Mardi; Mohammad-Reza Naghavi; Eslam Majidi Heravan; Babak Nakhoda; Amin Azadi; Ghasem Mohammadi-Nejad
Abstract
In order to identify yield and yield component QTLs under control and salt-stress conditions, a population of 254 recombinant inbred lines (RILs), derived from a cross between two bread wheat cultivars, (Roshan / Sabalan), was assessed. Parents and their 254 recombinant inbred lines (RILs) were evaluated ...
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In order to identify yield and yield component QTLs under control and salt-stress conditions, a population of 254 recombinant inbred lines (RILs), derived from a cross between two bread wheat cultivars, (Roshan / Sabalan), was assessed. Parents and their 254 recombinant inbred lines (RILs) were evaluated in an alpha-lattice design with two replications in two control and saline environments of Yazd in 2011-2012 cropping season. Yield and yield-related traits were evaluated at harvest time. The genotyping was carried out using SSR and DArT markers. A, B and D genomes were covered by 411.8, 620.4 and 67.5 cM, respectively. Also, a total of 48 QTLs were detected on 11 chromosomes for grain yield, biological yield, harvest index, thousand-kernel weight, grain number per spike, spike weight and spikelet number per spike. Roshan (salt tolerance) alleles were associated with an increase yield under saline conditions. SSR markers including gwm146, gwm577, gwm249 (on chromosomes 2A and 7B) were tightly associated with different QTLs. The major effect QTLs were located on chromosomes 1A and 7B for grain yield, harvest index and spike weight, which were explained 10.2%, 12.98% and 29 % of the total phenotypic variance, respectively. These QTLs and markers could be suitable for marker-assisted selection and gene stacking techniques. Moreover, co-located QTLs were detected on chromosome 2B for evaluated traits.
Germplasm genetic diversity & plant breeding
Shahrbanoo Abbasi; amin Baghizadeh; Ghasem Mohammadi-nejad
Abstract
In order to study the genetic conditions of some agronomic traits in wheat, a cross was made between Gaspard and Kharchia varieties. F2, F3 and F4 progenies with parents were evaluated under drought conditions. Three-parameter model [m d h] considered as the best fit for number of fertile tiller and ...
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In order to study the genetic conditions of some agronomic traits in wheat, a cross was made between Gaspard and Kharchia varieties. F2, F3 and F4 progenies with parents were evaluated under drought conditions. Three-parameter model [m d h] considered as the best fit for number of fertile tiller and flag leaf length using generations mean analysis method. For number of grain per spike and main spike grain weight three-parameter model [m d i] was used. For number of spikelet per spike, grain yield and plant height four-parameter model [m d h i] was used. The heritability values ranged from 56% for flag leaf length to 81% for grain yield. The F3 generation with 100 individuals was used to construct a genetic linkage map. Using the method of composite interval mapping 3, 1, 5, 2, 2 and 1 QTLs were detected for plant height, grain yield, number of spikelet per spike, flag leaf length, main spike grain weight and number of fertile tiller respectively.
Plant breeding for abiotic & biotic stresses
Ehsan Mohsenifard; Mehdi Ghabooli; Nastaran Mehri; Behnam Bakhshi
Abstract
Drought stress is one of the most determinative factors of agriculture and plays a major role in limiting crop productivity. This limitation is going to rising through climate changes. However, plants have their own defense systems to moderate the adverse effects of climatic conditions. MicroRNA-mediated ...
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Drought stress is one of the most determinative factors of agriculture and plays a major role in limiting crop productivity. This limitation is going to rising through climate changes. However, plants have their own defense systems to moderate the adverse effects of climatic conditions. MicroRNA-mediated post-transcriptional gene regulation is one of these defense mechanisms. The root endophytic fungus Piriformospora indica enhances plant tolerance to environmental stress based on general and non-specific plant species mechanisms. In this work, we investigated the effects of drought and P. indica inoculation on the expression of two important miRNAs, miR159 and miR396, in rice plants. To this end, leaf samples were harvested at control (F.C.) and severe drought stress (25% F.C.) in P. indica-colonized and non-inoculated rice plants 4 weeks after fungal inoculation. We have observed contrary expression patterns of miR396 (down-regulated) and miR159 (up-regulated) under drought stress condition. However, both miRNAs showed up-regulation by P. indica inoculation. We have observed significant up-regulation of miR396 and miR159 by treatment of P. indica under drought stress condition. Regulation of growth, hyposensitivity response and bio-water saving pathways directly affected by MYB and GRF transcriptional factor. So, remarkable change of miR156 and miR396 could lead plant to be tolerable under drought stress by the fine regulation of MYB and GRF, respectively.
Plant breeding for abiotic & biotic stresses
Hamid Reza Ghorbani; Habibollah Samizadeh Lahiji; Ghorban-Ali Nematzadeh
Abstract
Salinity is one of the most important abiotic stresses that decrease crop production. Transcription factors (TFs) are prominent regulators in plant responses to abiotic stress. In the present study, the expression pattern of four salt-induced genes encoding transcription factors, namely, MYB, RF2, GTF, ...
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Salinity is one of the most important abiotic stresses that decrease crop production. Transcription factors (TFs) are prominent regulators in plant responses to abiotic stress. In the present study, the expression pattern of four salt-induced genes encoding transcription factors, namely, MYB, RF2, GTF, and ARID was studied in response to salt stress (sodium chloride) and recovery conditions. The results of quantitative real-time PCR (qPCR) showed that expression of genes was influenced by salt stress in A. littoralis. The expression level of all genes increased after 6 hours treatment by salt and after that, it drastically decreased with promoting of stress duration in both roots and shoots tissues but in a different manner. The expression of MYB gene in root (68.44) was the higher than shoot (38.57) after 6 hours of salt treatment, while the expression of other studied genes in the shoot was higher than root. At the recovery stage, the up-regulated expression of genes in different tissues gradually decreased and finally gets a stable value. The result showed that the studied transcription factors play an important role in tolerance of A. littoralis to salinity and could be used as an informative resource in the future breeding programs aimed to develop salt tolerant plants. Also, the response of A. littoralis to salt stress depends on the tissue type and duration of plant exposure to salt.
Plant breeding for abiotic & biotic stresses
Behrouz Barzegargolchini; Ali Movafeghi; Ali Dehestani; Pooyan Mehrabanjoubani
Abstract
Salinity is one of the most important agricultural issues causing considerable yield reduction in agricultural crops. The main adverse effects of salinity are due to excess amount of sodium ions that is toxic to plant cells. Most halophytes are equipped with defense mechanisms enabling them to tolerate ...
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Salinity is one of the most important agricultural issues causing considerable yield reduction in agricultural crops. The main adverse effects of salinity are due to excess amount of sodium ions that is toxic to plant cells. Most halophytes are equipped with defense mechanisms enabling them to tolerate the salty habitats. Among grass plants, Aeluropus littoralis is a known monocots halophyte that can tolerate harsh saline conditions. In this study, salt treatment was applied in three levels of 0, 200 and 400 mM NaCl after 45 days and biological samples were collected at 7, 14 and 21 days after treatment (DAT). For microscopic analysis, the tissues were cross-sectioned and stained using methylene blue for lignified tissues and Congo red for cellulosic tissues. The amounts of Na+ and K+ were measured by flame photometer and the content of lignin was measured by polymeric thioglycolic acid derivatives method. The results showed that the amount of Na+ increased 13-fold, while the stem length, stem diameter, vascular bundle number, metaxylem diameter, phloem diameter, K+, fresh weight and dry weight decreased significantly by 35%, 48%, 59%, 19%, 25%, 45%, 64% and 55% under salt treatment, respectively. The amount of lignin in stem did not significantly change under salinity. According to these results, A. littoralis can tolerate saline habitats by different adaptation strategies like the limitation of minerals transition and reduction of plant biomass. Furthermore, the concentration of lignin in metaxylem tissues and stele parenchyma led to increased resistance of halophytes in excess amounts of Na+.
Plant breeding for abiotic & biotic stresses
Namdar Moradi; Ali Dehestani; Heshmatollah Rahimian; Valiollah Babaeizad
Abstract
Cucurbits powdery mildew is one of the most detrimental diseases of cucumber plants worldwide. A detailed insight into the biological processes leading to resistance or susceptibility to the pathogen would pave the road for an efficient disease-resistance breeding program. In the present study, the molecular ...
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Cucurbits powdery mildew is one of the most detrimental diseases of cucumber plants worldwide. A detailed insight into the biological processes leading to resistance or susceptibility to the pathogen would pave the road for an efficient disease-resistance breeding program. In the present study, the molecular and biochemical responses of a resistant vs. a susceptible cucumber cultivar infected with Sphaerotheca fuliginea were investigated. The alterations in the activity of two antioxidant enzymes i.e. superoxide dismutase (SOD) and catalase (CAT) were analyzed during different time courses. The changing pattern of the expression of PR-8 gene (chitinase class III) was evaluated through qPCR. Results showed that the PR-8 gene expression was raised in the leaves of both cultivars 96 hours post inoculation (hpi), however, with a 6 times higher expression rate in resistant cultivar compared to the susceptible one. The results imply that PR-8 may be a key factor of resistance to the pathogen. For both cultivars, SOD showed similar activity pattern and was raised at the early hours post inoculation and showed a peak 6 hours post inoculation with higher activity in the resistant cultivar. In contrast, CAT showed distinct activity patterns between cultivars and showed comparatively higher activity in the susceptible host. The possible reasons for these differences are discussed. The results of the present work give a more clarified insight into the possible mechanisms behind the resistance to cucumber powdery mildew caused by S. fuliginea.
Plant breeding for abiotic & biotic stresses
Nayer Mohammadkhani; Reza Heidari; Nasser Abbaspour; Fatemeh Rahmani
Abstract
Molecular information of K+ accumulation in grapes is strongly required. Under salinity condition potassium transporters are inhibited by Na+. The aim of this study was to investigate the effects of salinity on the expression of K+ transporter genes in grape. Based on the previous screening study on ...
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Molecular information of K+ accumulation in grapes is strongly required. Under salinity condition potassium transporters are inhibited by Na+. The aim of this study was to investigate the effects of salinity on the expression of K+ transporter genes in grape. Based on the previous screening study on 18 grape genotypes, ‘H6’ and ‘Gharashani’ (tolerant) and ‘Shirazi’ and ‘GhezelUzum’ (sensitive) were selected. Plants were treated with 50 mM NaCl as a critical concentration that was not lethal for grapevine plants. Interestingly, the expression of VvKUP1, VvKUP2 and VvK1.1 genes highly increased in leaves of sensitive genotypes compared to tolerant ones. Also the expression of VvKUP1 and VvKUP2 genes were similar in the leaves of sensitive genotypes. There was a significant positive correlation (P
Plant breeding for abiotic & biotic stresses
Masoud Fakhrfeshani; Farajollah Shahriari-Ahmadi; Ali Niazi; Nasrin Moshtaghi; Mohammad Zare-Mehrjerdi
Abstract
Among abiotic stresses, salinity has been increasing over the time for many reasons like using chemical fertilizers, global warming and rising sea levels. Under salinity stress, the loss of water availability, toxicity of Na+ and ion imbalance directly reduces carbon fixation and biomass production in ...
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Among abiotic stresses, salinity has been increasing over the time for many reasons like using chemical fertilizers, global warming and rising sea levels. Under salinity stress, the loss of water availability, toxicity of Na+ and ion imbalance directly reduces carbon fixation and biomass production in plants. K+ is a major agent that can counteract Na+ stresses, thus the potential of plants to tolerate salinity is strongly dependent on their potassium nutrition. HKTs (High-affinity K+ Transporters) are a family of transporters that mediate Na+-specific or Na+-K+ transport and play a key role in the regulation of ion homeostasis. In this study, we intended to focus on Electrolyte Leakage, ratio of K+/Na+, transcriptomic responses of a subclass two HKT in the roots of Aeluropus littoralis under salt stress. We investigated a noticeably different expression pattern over studied time points and found a snappy increase of AlHKT and rebalance of K+ concentration. It can be suggested that the early and high response of a Na+-K+ coupled transporter acted as a part of A. littoralis salt tolerance.
Plant breeding for abiotic & biotic stresses
Abbas Hajipour; Mohammad-Mehdi Sohani; Valiollah Babaeizad; Hasan Hasani-Kumleh
Abstract
The root endophytic fungus, Piriformospora indica, colonizes roots of a large number of plant species including Cereals and Brasicaceae. There are several reports indicating that P. indica protects roots from different path- ogens. In the present study, rice plants were pre-inoculated with P. indica ...
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The root endophytic fungus, Piriformospora indica, colonizes roots of a large number of plant species including Cereals and Brasicaceae. There are several reports indicating that P. indica protects roots from different path- ogens. In the present study, rice plants were pre-inoculated with P. indica and were subsequently infected with Fusarium proliferatum, as the causal agent of root rot and crown rot (Bakanae) disease. The effects of P. indica on the protection of rice plants against F. proliferatum were evaluated. Transcription levels of some pathogenesis-related genes such as NPR1, PR1, PR4 and PR5, as well as two transcriptional factor genes namely WRKY62 and WRKY85 were quantified via quantitative real time PCR in rice roots. Pre-inoculated and challenged rice plants showed mild disease symptoms with two weeks delay compared to non P. indica colonized plants. Quantification of Fusarium in roots via q-PCR con- firmed the higher quantity of the fungi in non pre-inoculated plants. Expression analysis revealed a faster induction of pathogenesis related genes following F. proliferatum inoculation of pre-inoculated plants i.e. priming of these genes is a part of mechanism of P. indica induced systemic resistance.
Plant breeding for abiotic & biotic stresses
Khalil Malekzadeh; Ali Niazi; Farajollah Shahriari-Ahmadi; Amin Mirshamsi-Kakhaki; Mohammad Zare-Mehrjerdi
Abstract
Salinity is one of the most important abiotic stresses that limit crop growth and production. Salt stress influences plants in two ways: by affecting ion toxicity and increasing osmotic stress. Ion homeostasis, the excretion of Na+ and using antioxidant systems are the major strategies of salt tolerance ...
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Salinity is one of the most important abiotic stresses that limit crop growth and production. Salt stress influences plants in two ways: by affecting ion toxicity and increasing osmotic stress. Ion homeostasis, the excretion of Na+ and using antioxidant systems are the major strategies of salt tolerance in plants. Na+ and K+ transporters with enzymes that are involved in detoxification of reactive oxygen species play key roles in salt tolerance in plants. The aim of this study was to investigate the responses of high affinity K+ transporter2;1 gene (HKT2;1) which is involved in regulation of ion homeostasis and L-gulonolactone oxidase (GLOase) which is involved in the ascorbic acid biosynthesis pathway, under different concentrations of NaCl over different time points in Aeluropus littoralis shoots. Results from Real Time PCR data showed that expressions of both genes were influenced by external and internal concentrations of Na+ and the internal K+ content. AlHKT2;1 was significantly upregulated by increasing Na+ concentration at all time points. Furthermore, its highest expression level in shoots occurred after 6 days in 300mM NaCl in shoots which was 25folds more than untreated shoots. AlGLOase expression levels increased 54 h after initiation of salt stress. These results indicate that AlHKT2;1 and AlGLOase respond to different salinity conditions and probably are part of the mechanisms involved in tolerance to high salt concentrations in A. littoralis.