حسن رهنما

Gene drive technology is one of the modern technologies that have many potential uses in the agriculture, industries and medical sciences. Like other technologies, this technology has some biosafety issues related to human and animal health and the environment. These issues were discussed in this article. The most important issue is related to changing in Mendelian inheritance template in filial generations and distribution of a specific allele in a local population. Moreover, adequacy of the national and international laws and regulations related to GMOs for gene-drived organisms, and also the risk assessment methods for gene-drived organisms including identification of possible risks of the gene-drive technology and containment of the gene-drived organisms during field experiment were discussed. In the following, the possible risks in release of gene-drived organisms were considered and some related aspects including the risks related to pathogen control, the risks related to invasive species control, the risks related to control agricultural pests, and the other social and economic dimensions were investigated.

Safflower with low oleic acid content is one of the native plants of Iran. Generally,, high oleic acid oils have more oxidative stability than the oils with high linoleic acids . Genome editing technology enable us to obtain oilseeds with high oleic acid. In this research, two guide RNA sequences were designed to target of Fatty Acid Desaturase 2 (FAD2-1) gene, which were located within the coding region and at a distance of 640 base pairs from each other. The guide sequences along with the codon optimized Cas9 gene were cloned in the T-DNA region of the Agrobacterium construct and transferred to the safflower by the In-planta method. The resulting seeds were cultivated and the plants were screened to track changes in the fatty acid profile of the seeds. The results showed that the amount of oleic acid in the seeds of one of the lines reached 53.14% on average. This line had four amino acid changes (L66F, N204D, S236A and I238V) at the same time. This is while the amount of oleic acid in the control plant was measured as 11.62% on average. The results showed that in the segregating generation, the change in fatty acid profile occurred in the line with homozygous amino acid change, and the heterozygous plants have the same oil profile as the control plants. Also, the results of this research can indicate the possibility of increasing the amount of oleic acid in oilseeds by changing the FAD2 enzyme sequence and without gene knockout.

Potato virus Y (PVY) is one of the most damaging viruses of potato plants which infects most cultivars and causes a significant decrease in yield products quality and also economical losses annually. Recently, the application of pathogen derived resistance mechanisms has opened new horizons for the development of virus-resistant transgenic plants. This research was carried out to study RNA silencing to engineered potato plants that are resistant to potato virus Y (PVY). RNAi construct was designed from coat protein (CP) segment of PVY. Potato explants were transformed by Agrobacterium tumefaciens AGL1 with pCAMRNAiCP containing bar selectable gene. The rate of regenerated plants was evaluated in the selected medium containing the herbicide phosphinotricin after growth and propagation. Transgenic plants and their gene expression were investigated using polymerase chain reaction (PCR) and RT-PCR. Results showed that 42 percent of regenerated plants were transformed. The expression of CP hairpin construct was determined by RT-PCR analysis in most of the lines. PVY resistance bioassay showed that 82 percent of transgenic potato plants were resistance to PVY.

he high efficiency of gene transfer to maize (Zea mays L.) using a standard binary vector is used widely in studies of genetic engineering and functional Genomics. The objective of the present study was to enhance efficiency of gene transfer to maize varieties using heat shock and hormones. To do this, embryo induction and plant regeneration from immature embryos of B73 and Mo17 cultivars immature embryos (1.5- 2 mm) were infected with Agrobacterium tumefaciens strain AGLO1 harboring pCAMBIA3301 binary vector containing gus gene. The immature embryos were treated by T1 (46 °C for 3 min, on ice for 1 min, centrifugation in 20000 g at 4 °C for 30 min) and T2 (without T1 treatment) treatments before inoculation with Agrobacterium. Moreover, the effects of Dithiothreitol (DTT) and Pluronic acid F68 (F68) detergents were studied on transformation efficiency by adding them to culture media. The results showed that heat shock and centrifugation treatments improved slightly genetic transformation of B73 but not on Mo17. The addition of DTT or F68 to co-culture medium led to a dramatic increase in T-DNA transfer to the B73, while there was no effects on Mo17 transformation. In B73, depending on the type of treatment, 18-5% of the immature embryos were produced resistant calli to phosphinotricin (PPT). Histochemical GUS assay on 8 weeks calli resistant to PPT and PCR analysis confirmed the transferring and expression of gus gene. These analyses showed 18% transformation frequency in T1+F68 treatment in comparation with 0% in T2-Detergents. Based on our results, the treatment T1+ F68 was suggested an efficient methodology to transfer genes by Agrobacterium to maize cultivar B73.

The application of the concept of pathogen derived resistance opened new horizons for the development of virus-resistant plants. In this mechanism، resistance to a virus is engineered in transgenic plants through the expression of a segment of the virus genome. This technique simply improves the development of crops which deliver high yields. On the other hand، there are some concerns about transgenic crops consumption. Also development in pesticides، chemical fertilizers and other technologies related to modern intensive agriculture threaten both human health and environment. Therefore the first step after transgenic plant production is to evaluate its potential benefits and risks to the environment and these should be compared to those generated by traditional agricultural practices. The main ecological concerns that are currently debated are complementation، heterologous encapsidation، synergy، plant-to-plant gene flow by outcrossing، plant-to-virus gene flow by recombination، effect on nontarget organisms، food and feed safety.