Showing 11 results for Transgenic
Volume 3, Issue 1 (3-2014)
Abstract
Brassica napus is an important oilseed crop and the yield loss due to fungal disease stem rot caused by Sclerotinia sclerotiorum is a serious problem in cultivation of this crop. The pathogenesis-related (PR) protein, glucanase, hydrolyzes a major cell wall component, glucan, of the pathogenic fungi and acts as a plant defense barrier. In this study, a β-1,3-glucanase (bgn13.1) gene was isolated from the biocontrol fungus Trichoderma virens-10 (showing the high β-glucanase activity) and cloned in pUC19 cloning vector. The cloned fragment was confirmed by molecular analysis and showed to contain two short introns, 52 and 57 bp and an open reading frame coding 761 amino acids. The bgn13.1 gene was over-expressed under the CaMV35S promoter in B. napus, R line Hyola 308. Transformation of cotyledonary petioles was achieved by pBIKH1 containing bgn13.1 gene via Agrobacterium tumefaciens LBA4404. The insertion of transgene was verified by the polymerase chain reaction (PCR) and genomic DNA Southern dot blotting in T0 generation. RT-PCR analysis indicated that the transgenic canola plants were able to transcribe the β-1,3 glucanase gene. Also, we used transgenic over-expression approach in order to investigate antifungal activity of expressed Bgn13.1 on S. sclerotiorum. The heterologous expressed Bgn13.1 of line # 7 and line # 10 compared with other lines showed stronger inhibition against hyphal growth of S. sclerotiorum with
F. Karimi , E. Khodaie,
Volume 9, Issue 2 (9-2018)
Abstract
Aims: In recent years, according the benefits of chloroplast transformation, the cultivation of transplastomic plants and their products have been increased. Due to their biosafety concerns, their identification and labeling have become more widely considered. The aim of this study was to present an optimal method based on polymerase chain reaction (PCR) and nanobiosensor for detection of transplastomic tobacco plants and compare their sensitivity.
Materials and Methods: In the present experimental research, aadA gene as a chloroplast selectable marker was considered to design specific primer and probe. In PCR method, after optimization of aadA gene amplification, its sensitivity was evaluated with different percentages of transplastomic DNA. In nanobiosensor method at first, the labeled aadA probe was immobilized on graphene oxide (GO) and, then, hybridization reaction was optimized to identify target DNA sequence.
Findings: The amplification of 800 bp DNA related to aadA gene was observed. The PCR reaction allowed up to 5% DNA transplostomy tobacco to reproduce the aadA gene. In results of nanobiosensor after immobilization of aadA probe on GO, fluorescence emission was quenched and by adding the trasplastomic tobacco, DNA was observed again. In this method, up to 1% transplastomic tobacco DNA, fluorescence emission was significant in comparison with control tobacco plant.
Conclusion: The PCR method can detect a transplastomic tobacco plant with 5% DNA sensitivity and detect biomarker sensitivity with 1% DNA sensitivity.
The PCR method can detect a transplastomic tobacco plant with 5% DNA sensitivity and nanobiosensor can detect with 1% DNA sensitivity. Therefore, nanobiosensor method is not only a reliable diagnostic method, in addition to the PCR method for detecting transplastomic plants, but also has a higher sensitivity.
Volume 9, Issue 2 (2-2020)
Abstract
Curly top is one of the most important viral diseases of sugar beet. Use of resistance sources is a promising strategy for control of this disease. In the present study, the efficiency of four gene silencing constructs (OUT-hp، IN-hp، sense and antisense) against two major causes of curly top disease in Iran, beet curly top virus-Svr (BCTV) and beet curly top Iran virus (BCTIV), were evaluated in transgenic plants. Selection of transgenic plant seeds was carried out on selective medium 1/2MS containing glufosinate-ammonium (Basta) and the results showed that the pBCTV-IN-hp construct resulted in the highest germinated seeds. Selected plants were transferred to greenhouse and evaluated for resistance to basta and detection of silencing constructs in the transgenic plants. Afterwards, resistance of the selected transgenic plants to beet curly top viruses and resistance stability against cucumber mosaic virus (CMV) was evaluated in a completely randomized design with six treatments in a factorial experiment. The results showed that the transformed lines with each of four constructs were significantly different in severity of symptoms, plant height and number of flowering stems compared to their respective controls. Although these transgenic plants were resistant to BCTV-Svr and BCTIV, in their challenge inoculation experiments it was shown that this resistance was suppressed by CMV infection.
Volume 9, Issue 3 (7-2007)
Abstract
The performance and flight behavior of the potato aphid Macrosiphum euphorbiae was studied on the 'Superior-BT' line transgenic for the CryIIIA toxin of Bacillus thuringien-sis (BT), resistant to the Colorado potato beetle; and non transformed 'Superior' line which served as control. Mortality of the treated aphids was negligible and potato lines did not affect the development time of M. euphorbiae, but aphids were largest on 'Supe-rior' and smallest on BT potatoes. This difference was reflected in aphid fecundity, which was lowest on 'Superior-BT', and highest on Superior. Incidence of flight in newly emerged alate M. euphorbiae that developed on BT was high compared to control. The re-sults illustrate that the performance of a secondary pest of potato can be unpredictably affected by the resistance factor involved in developing specific resistance to a primary pest.
Volume 14, Issue 5 (9-2012)
Abstract
Pyramiding genes related to grain quality and resistance through marker assisted selection (MAS) is an important approach in rice breeding programs. Marker-assisted selection can be used for monitoring the presence or absence of these genes in breeding populations and can be combined with conventional breeding approaches. This study is a part of cultivar development program in Iran through integration of conventional breeding with marker assisted selection. Crosses between two high yielding transgenic lines carrying an insect resistance gene (cry1Ab, from Bacillus thuringiensis) with a local aromatic variety were made followed by selection for incorporation of insect resistance and aroma (fgr) genes in desirable single F2 plants. Finally, plants homozygous for aroma and carrying cry1Ab genes with good agronomic performance were identified. Further analyses are underway on these plants in F3 generation. These plants promise to develop new aromatic Bt rice lines through integration of classical and molecular breeding in the near future in Iran
Volume 15, Issue 5 (9-2013)
Abstract
Transgene integration and expression in host plant is quite unpredictable and is considered as the major problem in plant transformation. The variation in transgene copy number in transgenic plants influences the expression level and is one of such complication. In many plant species, the analysis of transgenic plants has shown that independent transgenic plants have one to many copies of transgenes. This study focused on molecular characterization of difference in copy number of transgenes and its impact on expression level on mRNA basis. Four advanced transgenic lines of phytochrome B were analyzed for the integration of the gene. These transgenic lines were taken out on the basis of difference in copy number as determined by Southern blot analysis and Fluorescence in situ hybridization (FISH) for transgene expression. Results taken by both real time PCR and Northern blot analysis determined high expression in Line QCC11 having two copies of transgenes in homozygous condition while the least expression was seen in lines QCC10 showing three copy number in heterozygous condition as multiple copies can be incorporated from one to few insertion sites.
Volume 17, Issue 2 (3-2015)
Abstract
Manipulation of different genes in crop plants to get desirable characters has become an important tool of plant biotechnology. In the current study, cotton variety MNH-786 was modified for its characteristics to show resistance against lepidopteran insects and herbicide by transformation of Cry1Ac+Cry2A and GTGene cloned in a different cassette under 35S Promoter. Mature embryos of cotton MNH-786 were injured by a sharp blade at the shoot apex and infected with the Agrobacterim tumefaciens harboring transgene constructs. Transformed cotton plants were successfully acclimatized in pots and later the green house. Gene specific PCR and ELISA confirmed the transgene presence and its protein expression which was considerably higher in transformed plants. Overall transformation efficiency was 1.05%. All larvae of Helicoverpa armigera feeding on transgenic cotton leaves of T0 were found dead as compared to the control ones feeding on leaves from non-transgenic cotton. Transgenic plants also survived a glyphosate spray dose of 1,900 ml acre-1 as compared to herbs/weeds growing along with them, which burned completely five days post glyphosate application.
Volume 17, Issue 2 (3-2015)
Abstract
Low phosphorous (P) availability in soils limits production of soybean [Glycine max (L.) Merr.] around the world. This study was conducted to determine whether exogenous expression of the rice (Oryza sativa L.) phosphates transporter gene OsPT2 would increase inorganic phosphates (Pi) acquisition and improve yield in transgenic soybean. Cotyledonary-node explants of the soybean were inoculated with the Agrobacterium tumefaciens strain EHA105 harboring the vector pCAMBIA3301-OsPT2, which contained OsPT2, gus and bar genes. Ten fertile T0 transgenic plants were obtained and semi-quantitative RT-PCR of progenies demonstrated that OsPT2 gene was overexpressing in the T2 generation. Three T2 transgenic lines overexpressing OsPT2 were selected and subjected to testing for tolerance to low concentrations of Pi (low-Pi; 20 μM Pi) by hydroponic culture using modified Hoagland’s nutrient solution. The total P contents in the leaves, stems, roots, and seeds of the transgenic plants significantly increased under the concentrations of low-Pi and 1,000 μM Pi of standard Hoagland’s nutrient solution. Under low-Pi stress, the yields of the transgenic lines were significantly higher than those of the wild type. Taken together, our data suggest that the overexpression of OsPT2 in transgenic soybean lines improves Pi acquisition and seed yield, and OsPT2 may serve as one of the promising target genes that can be manipulated in crop improvement for minor use of Pi fertilizers.
Volume 22, Issue 6 (11-2020)
Abstract
Genetic manipulation to get desirable characters in cash crops like cotton remains the prime objective of crop biotechnology. To produce transgenic plants resistant against bollworms, newly emerged embryos of MNH-786 cotton variety were transformed with Agrobacterium tumefaciens strain LBA4404 harboring the plasmid pKHG4 vector containing Cry1Ac+Cry2A genes under the control of CaMV35S promoter. The integration and expression of these genes were evaluated by PCR, Florescent In-Situ Hybridization (FISH), and ELISA, respectively. Out of 700 putative transgenic cotton plants, 10 plants (1.03% transformation efficiency) showed the presence of genes Cry1Ac+Cry2A through PCR analysis. In vitro, insect feeding bioassay was done for estimation of mortality percentage of Helicoverpa armigera. Insect mortality rate and morphological characteristics of Bt cotton were analyzed by phenotypic correlation, path coefficient regression and covariance to evaluate the advantage of transgenic technology in numerical terms. Statistical analysis indicated significant positive correlation between insect mortality and cotton seed yield. Helicoverpa armigera mortality data produced a directly proportional relation with cotton seed yield. The results of this study support the improvement of cotton defense mechanism against insects and natural competitors through genetic modification.
Volume 23, Issue 2 (3-2021)
Abstract
Since the commercialization of transgenic crops in 1996, the biotech crop planted area has continuously increased. The European consumers have particularly been sceptical about transgenes in food products and EU (European Union) has enacted very complex legislation. The area of food analytics requires continuous development and improvement of detection methods to track the legislative framework and respond to consumers requirements. In the last decade, real-time PCR (polymerase chain reaction) based methods have been the methods of choice for numerous laboratories, but for various reasons, end-point PCR based methods have still been used. In our research, 73 samples of food and feed were analysed for the presence of common elements of transgene construct – Cauliflower Mosaic Virus 35S promoter (P-35S) and Agrobacterium tumefaciens Nopaline Synthase Terminator (T-NOS), using end-point PCR based methods. These samples had been previously tested for the presence of the same elements using validated real-time PCR based methods. Comparison of the used methods sensitivity showed that real-time PCR based methods have undeniable advantage. More important factor is specificity, and the fact that the list of approved Genetically Modified Organisms (GMOs) is constantly increasing necessitates updating of validation methods procedures. Considering upward trend of approved GMOs, it is important to pay more attention to the improvement and specialization of GMO detection methods.
Volume 24, Issue 1 (1-2022)
Abstract
Food security in developing countries faces new challenges these days. Scientific developments and biotechnological applications such as transgenic products are of particular importance due to their principal impact on key contexts such as food production. If transgenic products are a potential solution to the world's challenges, authorities need to know and understand the core of society's responses to scientific innovations and their products. This paper expands the body of knowledge by examining the predictors of transgenic product consumption by mediating the role of food integrity. The study population included 681 faculty members of Shiraz University in Iran. The sample size was estimated at 140 faculties using the stratified random sampling method, based on the Cochran formula. The results of applying path analysis showed a good fit of the variables entered in the conceptual model (RMSEA= 0.068). The explaining power of variables in the model respectively include attitude to transgenic product, environmental concerns, trust, and ethical norms. Results of this investigation could be effective in providing practical solutions in social issues such as enhanced attitude to the transgenic product with cultural mechanisms, emphasis on ethical norms, and trust-building in the academic community. These factors, based on public awareness of human involvement in food systems, can be improved by planning and presentation by researchers from relevant business and executive organizations. Based on these findings, providing factors that ensure the health of people could reduce the level of concern about the issues of food integrity and lead to the ideal level of acceptance and consumption of transgenic products.
