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Showing 4 results for Subject: Genetic engineering
Shahnoush Nayeri, Bahram Baghban Kohnehrouz,
Volume 8, Issue 2 (3-2022)
Abstract
Black poplar (Populus× euramericana Dode Guinier) is an industrially important tree with broad applications in wood and paper, biofuel and cellulose-based industries as well as plant breeding programs and soil phytoremediation approaches. Here, we have focused on development of direct shoot regeneration and Agrobacterium-mediated transformation protocols using the in vitro internodal stem tissue from hybrid black poplar. To obtain efficient plant regeneration, the internodal stem explant was cultured on SIM and RIM medium containing different concentrations of BAP × IBA and IBA × NAA, respectively. The crucial factors involved in genetic transformation have been evaluated to achieve Agrobacterium-mediated transformation protocol. We achieved fast and highly potential shoot regeneration from the explants cultured on SIM containing BAP 0.5mg/L and IBA 0.05mg/L with 28.57 shoots per explant. The normal roots developed from the plantlets cultured on RIM containing IBA 0.1mg/L and NAA 0.05mg/L and 100% of the regenerated plants were hardened and transferred to the greenhouse condition. Our results indicated that 0.5 µM Basta® could provide a stringent selection for the inhibition of non-transformed cells. We also obtained the highest transformation efficiency of 93.33% through preculturing the explants for 6 days and dipping into IM medium containing A. tumefaciens strain LBA4404 (OD600 = 0.6) and 100 µM AS for 10 min. The Southern blotting analysis, RT-PCR and GUS histochemical analysis were confirmed the stable single or two-copies gus transgenesis in the genomic DNA and its expression in the selected T0 generation plants. The findings indicate that these protocols could be used for genetic engineering approaches in hybrid black poplar.
Fatemeh Keykha Akhar, Abdolreza Bagheri, Nasrin Moshtaghi, Masoud Fakhrfeshani,
Volume 9, Issue 1 (9-2022)
Abstract
have been bred with altered flower color using genetic engineering approaches. One of the most effective applications is the reduction of flower pigments by suppression of involved enzymes in their biosynthesis pathways. RNA interference (RNAi) has provided an effective tool for the knock down of genes involved in the production of flower pigments. In this study, a chi-RNAi construct was designed for chalcone isomerase (chi) gene to transform Petunia plants. Transgenic lines in one phenotype showed 5.6 fold reduction in chi expression in comparison to the control. Chalcone and naringenin were also extracted and quantified. A 24% reduction in naringenin content was obvious in all transgenic lines. Generally, the results of this research showed that RNAi technology can be used as an efficient method for silencing the flower pigments in petunia. In addition, the chalcone isomerase gene was identified as one of the effective genes in anthocyanin biosynthesis pathway in Petunia plants which is involved in the production of color in these plants; hence, chi gene silencing resulted in clear phenotypic alterations in this plant.
Maryam Ehsasatvatan, Dr Bahram Baghban Kohnehrouz,
Volume 9, Issue 2 (3-2023)
Abstract
Plastid engineering gives numerous benefits for the next generation of transgenic technology, consisting of the convenient use of transgene stacking and the production of high expression levels of recombinant proteins. Designed ankyrin repeat proteins (DARPin) are relatively small non-immunoglobulin scaffold proteins that bind to their specific target with high affinity. The G3 is a type of DARPin designed to bind to the HER2 tyrosine kinase receptor (human epidermal growth factor receptor 2). We previously developed a bioprocess for the production of DARPin G3 in tobacco chloroplasts as an imaging agent in HER2 over-expressed cancers. In this study, we analyzed the expression and homoplasmic stability of DARPin G3 gene in vegetative and generative T1 generation of transplastomic tobacco plants. The presence of DARPin G3 gene in the next generation of transplastomic plants was confirmed with specific primers by PCR analysis. Southern blot analysis confirmed the homoplasmic status of transplastomic plants. The western blot analysis confirmed the accumulation of the DARPin G3 in the chloroplasts of next generation of transplastomic plants. The DARPin G3 protein content was estimated around 33% by ELISA in chloroplast total soluble protein (TSP) of the transplastomic plants. Results confirmed that the DARPin G3 gene in vegetative and generative T1 generation of transplastomic tobacco plants was stably and highly expressed.
Zahra Zarindast , Farhad Nazarian-Firouzabadi, Mitra Khademi,
Volume 10, Issue 1 (9-2023)
Abstract
Expression of antimicrobial peptides (AMPs) in plants to resist plant pathogens as well as to produce novel AMPs for pharmaceutical applications has recently received much consideration. alfAFP, a defensin cationic peptide synthesizing in alfalfa seeds, exhibits a strong antimicrobial activity. In order to facilitate alfAFP access to the pathogen’s membrane and increase the activity of the alfAFP peptide, the alfAFP encoding sequence was fused to the C-terminal of a chitin-binding domain (CBD) from a rice chitinase encoding gene. First, the antimicrobial properties of the recombinant peptide were assessed using bioinformatics tools. Next, the pGSA1285 expression vector harboring the CBD-alfAFP heterologous DNA was transformed into Agrobacterium rhizogenes for hairy root (HR) production in tobacco. The presence of transgene, transcription, and the expression of recombinant peptide in the HRs were confirmed by PCR and semi-quantitative RT-PCR analysis, respectively. Bioinformatic analysis was used to predict the antimicrobial activity of the alfAFP recombinant peptide. The results of the 3D structure analysis revealed a β-sheet and an α-helix structure that corresponded well with the structure of plant defensins. A Knottin functional domain was also recognized, suggesting that the recombinant peptide retains its antimicrobial activity. The results of the in vitro antimicrobial activity of the alfAFP recombinant peptide using CFU test showed that the recombinant peptide had significant inhibitory effects on Pseudomonas syringae pathogen. Therefore, the chitin-binding domain provided a better access of the recombinant peptide to the pathogenic bacterial cell wall through binding to peptidoglycan, and probably the recombinant peptide was able to target the plasma membrane with better efficiency. The results of this study suggested that the expression of the CBD-alfAFP recombinant peptide in crop plants and HRs can be a promising approach to producing pathogen-resistant plants as well as to produce new recombinant pharmaceutical AMPs.
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