جستجوی مقالات مرتبط با کلیدواژه « qRT » در نشریات گروه « بیوتکنولوژی و ژنتیک گیاهی »

Tobacco as a model plant (owing to certain features) is extensively used in molecular research with the aims to understand the fundamental plant and pathogen interactions. Fire blight bacterial disease of tobacco (Pseudomonas syringae pv. tabaci (Pst)) causes considerable damage to tobacco worldwide. Induction of genes associated with virulence that play a role in resistance to diseases can be effective in reducing the severity of disease. The evidence suggests that plant hormones are effective in gene expression in plants and increase the production of secondary metabolites. In addition, they stimulate the immune system of plant through the activation of transcription of genes linked with plant defense mechanisms that regulate the induced resistance. In this study, the expression of PR1, PR5, Pal, Catalase and WRKY12 in tobacco plants treated with salicylic acid at a concentration of 3 mM and tobacco plant treated with jasmonic acid at a concentration of 0.5 mM and also control plant in times 0, 12, 24, 48 and 72 after injection of Pseudomonas syrigae pv. tabaci was investigated by Quantitative Real-time PCR (QRT-PCR) technique. The results showed that jasmonic acid and particularly salicylic acid treatments caused significant changes in the expression of these genes after bacterial injection.

Compatible solutes or osmoprotectants serve as nontoxic solutes for cytoplasmic osmoregulation. Glycine betaine is one of the most critical compatible solutes accumulated by many plants in response to adverse effects of various abiotic stresses. In some species named Glycine betaine accumulators, Glycine betaine is synthesized by a two-step oxidation of choline by choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH) enzymes. According to the Arabidopsis thaliana genome database (TAIR) there are the most likely two AtALDH8 and AtALDH9 genes coding BADH enzyme. In this study, using the relative expression analysis via quantitative RealTime PCR, it has been evaluated how the expression pattern of these genes affected by drought levels in Arabidopsis thaliana tissues including fast expanding leaves, fully expanded leaves, and roots. It has been denoted that the mRNA induction level of the AtALDH9 gene varies in tissues in response to drought levels. However, the expression of AtALDH8 gene is affected negligibly by these factors. While 12-day of water withholding made no changes in the expression level of AtALDH9 gene in fully expanded leaves, the expression level of the gene were changed at about 0.7-fold and 4-fold in fast expanding leaves and roots, respectively. Differently, after 16-day of water withholding the expression level of AtALDH9 gene rose about 2.5-fold in fast expanding leaves and reduced about 0.2-fold in both fully expanded leaves and roots. Generally, it seems that AtALDH9 is the gene accountable in Arabidopsis in response to drought stress.

Sesame (Sesamum indicum L.) is one of the oldest oilseed crops that has been a main food source providing beneficial nutritional outcomes to human health due to its high contents of antioxidants and secondary metabolites. The importance of sesame arises from presence of antioxidant sesamin. Over recent decades, due to being used in cancer cases, there have been numerous efforts aimed at better understanding of the genes underlying sesamin biosynthesis and increasing their expression. In this research, expression levels of the key genes in sesamin biosynthesis pathway including CYP81Q1, CYP81Q2, CYP81Q3 and C3H genes were measured in 10 sesame cultivars seeds (Yekta, early Palestinian, Naz tak shakheh, Naz chand shakheh, Oltan, Jiroft, Dashtestan 5, Dashtestan 2, Varamin and Karaj 1) by QRT-PCR technique and 18S rRNA gene as reference gene. Our findings showed that the level of CYP81Q1 gene expression was low in Early Palestinian that has low sesamin content. Therefore, this might not be considered as a qualitatively desired oil cultivar compared to others, whereas Yekta had the highest level of CYP81Q1 expression the best varieties for oil production both qualitatively and quantitatively. The highest expression level of CYP81Q2 was observed in Naz chand shakheh, while the lowest CYP81Q2 expression was found in Early Palestinian. Karaj1, Yekta and Dashtestan 5 showed the highest whereas Oltan had the lowest expression level of C3H. Karaj 1, Yekta and Dashtestan 5 were relatively from the late mature group that was reported to have higher contents of oil and sesamin than early ones.

Artemisia annua is particularly important for the production of artemisinin, a bioproduct which can be used to combat the causal agent of malaria, treat some kind of cancers and in other activities. The low artemisinin content in the plant has caused this compound to be among the more expensive medicines. Several attempts have been made to increase artemisinin production, for example by using different elicitors, but none of the approaches has been cost effective. In this study, the expression levels of two important genes in the artemisinin biosynthetic pathway, SQS and DBR2 and artemisinin content were investigated in Artemisia cell suspension cultures. SQS and DBR2 genes have essential roles in the regulation of artemisinin pathway. For this purpose, nano-cobalt particles in concentrations of 0.25, 2.5 and 5 mg/L were used for cell culture treatment and samples were collected after 8, 24, 48 and 72 h. The highest artemisinin content was observed 24 h after 5 mg/L nanocobalt treatment. In this case, artemisinin production was 2.25 times (113.35 mg/g d.wt) higher than that of the control. Our results showed a negative and significant correlation between SQS and DBR2 gene expression and artemisinin content at different levels of nano cobalt treatments. Results also showed an increase in nano cobalt concentration after 72 hour and an increase in nano chitosan after 4h hour caused a significant decrease in the expression of SQS and DBR2 genes. In conclusion, it appears that the content of artemisinin was increased by high concentrations of the nano cobalt particles because of a decrease in the expression of SQS and DBR2 genes.

Salt stress is a serious problem for plant growth and development. To analyze salt stress resistance and physiological behavior of plants, the halophyte Aeluropus littoralis was studied. Salt stress augments ethylene hormone production in plant tissue and this leads to increased hydrogen cyanide levels. In the other hand, there is a cyanide purge mechanism involving three enzymes: Cyanase, Rhodanese and βcyanoalanine synthase. To study plant cell growth and development under salt stress conditions, an analysis of differential expression of genes involved in biosynthesis and purge of cyanide is needed. In this study, Aeluropus littoralis cell suspensions were subjected to different concentrations of salt and potassium cyanide in the medium. Factorial analysis of NaCl and KCN in 0, 0/0.2, 0/0.4, 60/0, 60/0.2, 60/0.4, 120/0, 120/0.2 and 120/0.4 mM concentrations were assessed. Our study demonstrated that KCN treatment significantly reduced production of dry material. The results showed that, although cyanide has negative effect on cell growth, the cyanide detoxification gene network was not activated in these conditions. In addition, the interaction between cyanide and salinity indicated that salt stress in the presence of 0.4 mM KCN increases cell growth by 40 percent because expression of the CAS gene was reduced enormously. An increase of salinity in the presence of 0.2 mM KCN, however, reduced expression of ACO, a key gene in HCN and ethylene production. As intracellular level of HCN declined, cell growth rose. Thus external treatment of cyanide increases plant dry material and plant resistance in salt stress conditions.

Plants encounter various stresses such as drought and salinity which adversely affect growth, development and crop productivity. The expression of the genes Delta -1- pyrroline – 5 - carboxylate synthetase (P5CS) and Betaine aldehyde dehydrogenase (BADH) extends throughout various protective mechanisms in plants and allows them to adapt to unfavorable environmental conditions. P5CS and BADH genes expression patterns in the wheat cultivars Mahuti and Alamut were studied under salt and ABA treatments using a qRT-PCR technique. Results showed that gene expression patterns were significantly different in these two cultivars. Mahuti had significantly higher expressions of P5CS at 3h compared to other time courses, while Alamut had significantly higher expressions of P5CS at 72h. In addition, these result showed that the P5CS gene expression increased after treatment of ABA and NaCl in both Mahuti and Alamut cultivars. Similarly, Mahuti had significantly higher expressions of BADH at 72h compared to other time courses, while Alamut had significantly higher expressions of BADH at 24h. It is likely that the difference in gene expression patterns between Mahuti as a salt tolerant cultivar and Alamut as a salt sensitive cultivar is due to different signaling pathways that activate P5CS and BADH expressions. Lack of significant difference between these genes expression profile under salt and ABA treatment suggest that P5CS and BADH are not induced by the stresses used in this study. It is also possible that different concentrations of NaCl and ABA are required to cause a change in the expression of P5CS and BADH genes.

GmOSBP and GmBZIP genes play a key role in signaling of response to certain physiological repercussion to stress and CAT gene plays a role through inhibition of ROS in plants This research was conducted to evaluate the expression profile of GmOSBP، CAT and GmBZIP genes in two soybean cultivars، Williams (tolerant) and L17 (susceptible) at salinity condition. Two soybean cultivars were cultured based on completely randomized design with three replicate in the greenhouse conditions، and salinity stress including zero (as non stress) and 300 mM NaCl treatments was performed at five-leaf stage plantlets for 7 days. The sampling from both from leaves and roots for two cultivars was performed in the same time at five-leaf stage. Total RNA was extracted from leaves and roots of both control and stressed plants. Then cDNA was synthesized and used for Real time PCR in two replications. To normalize data the housekeeping gene 18SrRNA was used. Data analysis based on Ct observations showed that the expression of three genes was increased under salinity stress in both leaf and root organs. The expression of GmBZIP gene in Williams was two-fold greater than L17 cultivar and its expression was higher in root than leaf. Also GmOSBP gene expression in L17 was two-fold greater than Williams’s cultivar and its expression was tree-fold greater in leaf than root. The expression of CAT gene in L17 was tree-fold greater than Williams and its expression was higher in root than leaf. According to increasing of salinity tolerance through the expression of these genes، it can be concluded that transferring of these genes may enhance salinity tolerance in other crops.

MicroRNAs (miRNAs) play important roles in numerous processes in plants including development، tissue proliferation، differentiation، hormone signaling and responses to biotic and abiotic stresses. SPL، the plant-specific transcription factors، are regulated by miRNAs and play important roles in several processes including tissue development، response to biotic and abiotic stress and induction of several other transcription factors and membrane proteins. In this study we selected miRNAs that regulate SPL transcription factors expression in rice. Later، the differential expression of these miRNAs are evaluated using qRT-PCR and Stem-loop primers. Results of shoot differential expression under drought stress showed that miR529 was down-regulated but conversely، miR535 was up-regulated. However، significant differential expression of miR156 was not observed in our study. Likewise، root differential expression under drought condition showed up-regulation of miR535، but miR529 and miR156 did not show any significant differential expression. Although all of these miRNAs are involved in regulating the expression of the same genes، but their diverse differential expressions highlight the complexity of gene-regulatory networks in various environmental conditions. Based on results of this study، it can be suggested that compared to miR535، miR156 and miR529 play more important roles in regulating the development and flowering process via controlling SPL transcription factors whereas، miR535، miR529 and relatively lesser miR156 are responsible for SPL transcription factor regulation under stress.

Herbivore feeding induces two main defensive systems in plant, direct and indirect defenses. To know role of some genes which involve in direct and/or indirect defenses their expression pattern were compared in clean and mite infested leaves of some common bean susceptible (Akhtar) and resistant (Naz, Ks41128) genotypes with QRT-PCR. Then to proof the QRT PCR results, preference of predatory mite, Phytoseiulus persimilis، were compared in all cultivars with olfactometer. The QRT-PCR results indicated that among genes only expression of LOX gene that is important in both direct and indirect defenses was significantly difference among genotypes. After spider mite infestation expression of LOX gene was significantly up-regulated only in the resistant genotype (Naz) and in the susceptible genotype (Akhtar) expression of LOX was even significantly down-regulated. The result of olfactory tests showed that only Naz genotype could significantly attract more predatory mites after the spider mite infestation. Therefore significantly more attraction of predatory mite to resistance genotype (Naz) than other genotypes and up regulation of LOX gene in this genotype upon mite infestation can demonstrate role of this gene in direct and indirect defense of common bean against spider mite.