In order to understand more clearly differences between different varieties of tobacco in quality characteristics of leaf chemical characteristics, six fire-cured varieties of tobacco were examined, DRV1, DRV10, Madole, Kentucky 171,Toleza68 and Western for absorption and accumulation determination potash and nitrogen in different plant parts and quality characteristics. Plants were grown in a unheated greenhouse in March of 1999, and then seedling transplanted into the field in spring year 1999, and in a randomized block design was planted with four blocks. Results showed that there were significant differences between different cultivars in percentage of root potash, root nitrogen, leaf nitrogen, stem potash and percentage of sugar. But percentage of leaf potash, stem nitrogen, nicotine, total ash and burning time were not different between different varieties. Amount of potash and nitrogen in different plant parts varieties were different at different stages of growth. The maximum and minimum absorotion of potash and nitrogen were observed at early and late stages of growth (42-58 and 94-122 days after  planting),respectively.

Powdery mildew caused by Erysiphe cichoracearum is an important fungal disease which threatens tobacco (NICOTIANA tabacum L.) production. The objective of this study was to determine DNA markers linked to genomic regions associated with resistance to powdery mildew in tobacco through the association mapping approach. Seventy tobacco genotypes were fingerprinted using 26 simple sequence repeat (SSR) primer pairs which were distributed in several chromosomes of tobacco.A total number of 66 alleles were detected by 26 SSR primers with an average of 2.53 alleles per locus. Based on population structure analysis, the studied genotypes were classified into three groups including Chopogh, PD and Tikolak genotypes. Ou of 325 marker pairs, 6.15% showed a significant level of linkage disequilibrium (LD) (P<0.01). The mean of D´ for all marker pairs was 0.268.Using susceptibility data of the 70 genotypes against fungal agent, three loci (pt30034, pt30008 and pt30159) from linkage groups 22, 11 and 14b of tobacco reference linkage map were identified to be associated with the gene (s) controlling resistance to powdery mildew.The identified markers could be good candidates for marker assisted selection in powdery mildew disease resistance breeding programs. However, like any other quantitative trait, there is a requirement to assess the quality of the obtained quantitative trait loci (QTLs) before marker assisted selection (MAS) become a viable proposition.

To assess the genetic diversity for morphological and agronomic traits in Iranian oriental tobacco germplasm, 100 oriental and semi-oriental tobacco genotypes from the Urmieh Tobacco Research Center collection were evaluated in the field using a simple square lattice design with two replications. Some agronomic traits were measured on five randomly selected plants in each plot. Genotypes were clustered into similar groups using UPGMA based on squared Euclidean distance after data normalization. Four distinct groups were established. Discrimination function analysis performed to determine the accuracy of the grouping developed by cluster analysis showed that the total success rate of grouping was 97%. Among developed groups, groups 1 and 4 had the maximum Mahalanobis distance value of 67.4. Results revealed that the first three discriminant functions were significant, and their standardized discrimination function coefficients indicated that among the studied traits, days to 50% flowering, dry leaf yield and number of leaves per plant were the most important for discriminating among tobacco genotypes.

Introduction: The technology of recombinant protein production has revolutionized biological, pharmaceutical, and medical researches. Plants are appropriate systems for the production of recombinant proteins. In the present study, a chimeric gene encoding a chimeric protein containing StxB, Eae, CfaB, and LTB as a candidate vaccine against enterotoxigenic and enterohemorrhagic E. coli, was transferred to the hairy root of the tobacco plant and its expression was analyzed.Materials and Methods: For this aim, the plant-based codon-optimized gene, which was synthetically cloned in pBI121 binary vector, was transferred into Agrobacterium rhizogenes competent cells. A. rhizogenes cells containing pBI121+secl were transferred into sterile NICOTIANA TABACCUM plants by direct and indirect methods. Finally, the expression of recombinant protein was analyzed by the ELISA method.Results: The transformation of A. rhizogenes cells and Tobacco plants was confirmed by PCR amplification of a fragment of the chimeric gene with specific primers. SDS-PAGE and ELISA analysis showed the successful expression of the chimeric recombinant protein.Conclusions: In conclusion, it was shown that the hairy roots of tobacco plant is a proper expression system for the recombinant production of SECL protein. The protein can be used for mice's immunization against enterotoxigenic and enterohemorrhagic E. coli strains.

Tobacco (NICOTIANA TABACCUM) is one of the valuable agricultural and industrial crops that there is little information about its variation. For studying genetic variation on the basis of morphological characteristics, a number of 100 exotic and endemic oriental tobacco genotypes were obtained from the germplasm collection of the Urmia Tobacco Research Center, Urmia, Iran, using simple lattice design with 2 replications. Eight traits include: stem height and diameter, leaf number per plot, leaf length and width, fresh and dry leaf weight and day to 50% flowering were examined. Principal component analysis could reduce the studied morphological traits to 5 components having 96% accumulative variance. In the first component, all traits (except stem height) showed positive significant correlations with. Cluster analysis using UPGMA method distinguished genotypes in 4 different groups. Maximum distance was between groups 1 and 4. Mean comparison revealed that genotypes (Trimph and Ohdaruma) belong to group 4 had the maximum value of most examined traits, therefore, they could be utilized as parents of crosses in breeding programs.

BackgroundNICOTIANA tobacco contains large amounts of alkaloid nicotine. Tobacco plant is used for smoking and causes many health problems since it is high in nicotine which is one of the widely-recognized toxic compounds with serious side effects for different body organs. Reducing nicotine content of this plant is a way to reduce its health hazards in cigarette smokers. Utilizing the new methods of genetic engineering can modify nicotine levels in the plant. In this study, through transferring the blocking gene, the pathway of nicotine biosynthesis was blocked to produce transgenic tobacco with low levels of nicotine.MethodsTransgenic plants carrying T DNA, and non-transgenic plants were grown on MS medium. Then their leaves were dried and powdered. The plants were extracted with alkali solution. Eventually, the nicotine content of the extract were analyzed using GC.ResultsThe analysis of extracts showed a reduction in the nicotine content of the transgenic plant (contain T-DNA) in comparison with non-transgenic plants.Conclusion: Tobacco with lower nicotine reduction can reduce the toxic effects of smoking on smokers and can facilitate withdrawal from it.

To improve Agrobacterium-mediated transformation of tobacco, factors influencing gene delivery, including genotype of the plant, bacterial strain, and Agrobacterium transformation procedure, were tested via direct somatic embryogenesis. Leaf tissue of three different tobacco genotypes (NICOTIANA tabacum L. cvs. Samsun, and Xanthi, and N. benthamiana) were used as explant. Leaf explants were transformed using three Agrobacterium tumefaciens strains (EHA105, GV3101, and LBA4404) harboring the binary vector pCAMBIA1304 using three different types of transformation methods as named Agro-inoculation, Agro-infection and Agro-injection. Selection of hygromycin resistant shoots was conducted on MS medium containing 3. 0 mgL-1 BAP and 0. 2 mgL-1 IAA, 250 mgL-1 cefotaxime and 30 mgL-1 hygromycin. Hygromycin resistant shoots were then rooted on MS medium supplemented with 250 mgL-1 cefotaxime and 15 mgL-1 hygromycin. The results indicated that A. tumefaciens strain LBA4404 was more effective in gene delivery than EHA105 and GV3101 and Agro-infection method proved to be significantly better than two other methods. The highest transformation rate was obtained with the Agrobacterium strain LBA4404 and Agro-infection method with approximately 72. 80%, 84. 57%, and 93. 33% for N. benthamiana, Samsun and Xanthi, respectively. Histochemical GUS assay confirmed the expression of gusA gene in putatively transformed plantlets. PCR and RT-PCR analysis using gene-specific primers confirmed the integration of the gusA and hpt genes and the expression of the gusA and hpt genes, respectively. Furthermore, Southern blot analysis confirmed stable integration of the gusA gene in selected T0 transformants.