Cell and Tissue Journal

Abstract Aim: The chlorophyll biosynthesis pathway is a main target for genetic modification to change plant photosynthesis and growth rate to support a greater demand for food in the growing world population. In this study, the effect of overexpression of GSA gene one of gene involved in biosynthesis pathway of chlorophyll on physiological condition of tobacco plant was investigated. 5-Aminolevulinate (ALA) is product of GSA gene. ALA is a precursor for all tetrapyrrole, these components have impotent roles in living cell, as pigments, light receptor (Phytochrome), prosthetic group of many different proteins (like cytochromes, hemoglobin, myoglobin, and leghemoglobin) and enzymes (for example Catalase, Ascorbate, Peroxidase and etc.). Nowadays, ALA has received wide attention for its widespread usage in agriculture, forestry and medication. ALA at low concentrations increases photosynthesis, growth, development, yield and productivity, also promoted fruit color appearance and quality and taste of products in treated plants under both normal and stressful conditions. ALA also improves antioxidant features, absorption of nutrient, water use efficiency and osmotic balance in plants.
Materials and methods: In this research, according to bioinformatics studies, MsGSA gene cDNA of Alfalfa (Medicago sativa L. cv. Isfahani) was selected to transfer to Xanthi tobacco (Nicotiana tabacum) plant, the binary expression vector pBI121 which has Kanamycin antibiotic resistance gene for selection in bacteria and plants, cutting sites for SacI and BamHI enzyme, CaMV35S promoter (cauliflower mosaic virus promoter), nos transcription termination sequences and ß-glucuronidase (GUS) reporter gene was used. After constructing the gene construct pBI121-GSA and confirming the transfer of the construct using PCR cloning methods, enzymatic digestion and sequencing were performed, then the corresponding construct was transferred to Agrobacterium tumefaciens strain LB4404 using Agrobacterium with the gene construct. The corresponding gene was transferred to the tobacco plant genome and the transgenic plants were selected on the medium containing kanamycin and the presence of the gene was confirmed by performing PCR in the regenerated plants. The rooted transgenic sprouts were transferred to the soil. The level of GSA gene expression in the resulting transgenic plants was evaluated by real-time PCR, and their growth rate and biochemical content were also evaluated.
Results: It was observed that the growth of transgenic plants increased significantly depending on the level of GSA gene expression, and the content of ALA (aminolevulinic acid) and chlorophyll a, b and total chlorophyll, which are the products of the corresponding gene expression. The results also showed the content of anthocyanin, flavonoids and phenol of plants have significantly increased in proportion to the increase in GSA gene expression compared to wild type tobacco plants.
Conclusion: The growth rate as well as the content of chlorophyll a, b, total chlorophyll, ALA, anthocyanin, flavonoids and phenol of transgenic GSA plants is proportional to the increase in the expression of the GSA gene. The results from this study indicate that an increase in transgenic growth rate as well as an increase in the secondary metabolites content in transgenic plants were influenced by GSA transferred gene and an increase in the content of ALA. These results imply that transgenic tobacco plants expressing MsGSA gene had higher resistance potential to stresses than the wild type tobacco plants.

Abstract Aim: In this study, the effect of silence on the expression of the key gene expression of DBOX (which encodes the final enzyme for the synthesis of two alkaloids, Sanguinarin and papaverin) was used by VIGS technique in a species of poppy (Papaver somniferum L.).
Material and methods: A fragment of 350 pairs of alkali from the DBOX gene sequence (within the range of 1112-1462bp) was selected based on the highest number of siRNA production with 21 nucleotides length. After cloning this segment into the pTZ57R/T vector and transferring the vector to pTRV2 viral vector, Agrobacterium inoculation liquid containing silencer was injected into the poppy plants leaves. Primary transgenic plants were selected by PCR reaction using a protein-binding protein coding gene primer (CP) and secondary screening was performed by semi-quantitative PCR technique. In the next step, the samples with the maximum silence (lowest expression) of the gene were examined by real-time RT-PCR technique.
Results: Cloning accuracy in pTZ57R/T and pTRV2 plasmids were confirmed using PCR and enzymatic digestion. Based on the results of semi-quantitative PCR, 5 transgenic plants were selected with the lowest expression for DBOX gene. Based on semi-quantitative PCR results, 5 transgenic plants with the lowest expression were selected for DBOX gene. The results of real-time RT-PCR showed averagely decrease of 81% in the expression of DBOX gene transcriptions in transgenic plants compared to control plants (inoculated with the pTRV2 empty plasmid).
Conclusion: The results generally showed that the VIGS technique could successfully reduce the DBOX gene expression in poppy plants. In addition, the results obtained for this gene can be used to understand the biosynthetic pathway of poppy alkaloids and transgenic plants for metabolic engineering purposes.
 

Abstract Aim: Papaver somniferum remains the sole commercial source for several pharmaceutical benzophenanthridine alkaloids from benzylisoquinoline branch alkaloids, which includes the narcotic analgesics codeine and the semi-synthetic drugs such as; oxycodone, buprenorphine and naltrexone. Although, most of the biosynthetic pathways genes of this alkaloid have been identified, the post-transcriptional regulation of these alkaloids pathway has not been completely determined. Virus induced gene silencing (VIGS) is a method for fast functional genomics, and in this study, this technique was used to investigate the silencing one of the most important genes in this alkaloid pathway.
Materials and Methods: In the current research VIGS technique was used for systematic reduction in the level of genes expression involves in benzylisoquinoline alkaloids pathway. For silencing of codeinone reductase gene, pTRV vector was used for cloning. The specific silencing of COR gene was evaluated in 2-3 weeks old leaves of Papaver somniferum using agro-infiltration method.
Results: Result of cloning was confirmed by using of different molecular methods such as enzyme digestion and also PCR. PCR technique was used for confirmation of transgenic plants in some transformed plants. Using of semi-quantitative PCR and real-time PCR showed that the level of reduction in transcription of COR gene was about 89 percent.
Conclusion: The obtained results confirmed that by application of RNA interference method, the level of COR gene expression was significantly reduced compared with control.