A.Youssef, SaharSayed, YasminS. Hassan, OsamaSafwat, GehanA. Shalaby, A.2019-10-222019-10-2220071. Ahrens U., Seemüller E. 1992. Detection of plant pathogenic mycoplasma-like organisms by a polymerase chain reaction that amplify a sequence of the 16S rRNA gene. Phytopathology, 82: 828- 832. 2. Akhtar, K.P., M. Dickinson, G. Sarwar, F.F. Jamil and M.A. Haq. 2008. First report on the association of a 16SrII phytoplasma with sesame phyllody in Pakistan. Plant Pathol. 57: 771. 3. Anonymous. 2010. Sesame production data. http://faostat.fao.org/. 4. Cagirgan M.I., N. Mbaye, R.S. Silme, N. Ouedraogo and H. Topuz. 2013. The impact of climate variability on occurrence of sesame phyllody and symptomatology of the disease in a Mediterranean environment. Turk. J. Field Crops 18(1): 101-108. 5. Davis R.E., Lee I.-M. 1993. Cluster-specific polymerase chain reaction amplification of 16SrDNA sequences for detection and identification of mycoplasma-like organisms. Phytopathology, 83: 1008-1011. 6. Dellaporta SL, Wood J, Hicks JB, 1983. A plant DNA minipreparation: version II. Plant Molecular Biology Reporter, 19–21. 7. Delić, D., Seljak, G., Martini, M., Ermacora, P., Carraro, L., Myrta, A. Đurić, G. 2007. Surveys for grapevine yellows phytoplasmas in Bosnia and Herzegovina. Bulletin of Insectology, 60 (2), pp. 369-37. 8. Deng S., and Hiruki C. 1991. Amplification of 16S rRNA genes from culturable and nonculturable Mollicutes. Journal of Microbiology Methods, 14: 53-61. 9. Doi, Y., M. Teranaka, K. Yora and H. Asuyama. 1967. Mycoplasma- or PLT group-like microorganisms found in the phloem elements of plants infected with mulberry dwarf, potato witches’ broom, aster yellows or paulownia witches’ broom. Ann. Phytopathol. Soc. Jpn. 33 (4):259–266. 10.El-Bramawy M.A.S. 2006. Inheritance of resistance to Fusarium wilt in some sesame crosses under field conditions. Plant Protection Science 42:99-105. 11.Firrao, G., E. Gobbi, and R. Locci. 1994. Rapid diagnosis of apple proliferation mycoplasma-like organism using a polymerase chain reaction procedure. Plant Pathol. (London) 43:669–674. 12.Faostat database. 2012. Food and Agriculture Organization of the United Nations. http://faostat.fao.org/ 13.Gundersen D.E., Lee I.-M. Song, Y., Lou, B., Bai, X., Deng, C., Chen, Y., Zhao, X., & Li, X. 2015. Possibility of seed transmitting huanglongbing caused by Candidatus Liberibacter asiaticus. Journal of Southern Agriculture, 46(5), 813-816 Ultrasensitive detection of phytoplasmas by nested-PCR assays using two universal primer pairs. Phytopathologia Mediterranea, 35:144-151. 14.Harrison N.A., Richardson, P.A., Tsai J.H., Ebbert M.A., Kramer J.B. 1996. PCR assay for detection of the phytoplasma associated with maize bushy stunt disease. Plant Disease, 80: 263-269. 15.Jarausch, W., C. Saillard, F. Dosba, and J.-M. Bove´. 1994. Differentiation of mycoplasma like organisms (MLOs) in European fruit trees by PCR using specific primers derived from the sequence of a chromosomal fragment of the apple proliferation MLO. Appl. Environ. Microbiol. 60:2916–2923. 16.Jomantiene R., Davis R.E., Maas J., Dally E.L. 1998. Classification of new phytoplasmas associated with diseases of strawberry in Florida, based on analysis of 16S rRNA and ribosomal protein gene operon sequences. International Journal of Systematic Bacteriology, 48: 269-277. 17.Kirkpatrick, B. C., C. D. Smart, S. L. Gardner, J.-L. Gao, U. Ahrens, R.Ma¨urer, B. Schneider, K.-H. Lorenz, E. Seemu¨ller, N. A. Harrison, S. Namba, and X. Daire. 1994. Phylogenetic relationships of plant pathogenic MLOs established by 16/23S rDNA spacer sequences. IOM Lett. 3:228–229. 18.Kolte, S.J. 1985. Diseases of annual edible oil seed crops. Vol. II. CRS Press, p135. 19.Lee, I.-M., R. W. Hammond, R. E. Davis, and D. E. Gundersen. 1993. Universal amplification and analysis of pathogen 16S rDNA for classification and identification of mycoplasmalike organisms. Phytopathology 83:834–842. 20.Lee I.-M., Gundersen D.E., Hammond R.W., Davis R.E. 1994. Use of mycoplasma-like organism (MLO) group-specific oligonucleotide primers for nested-PCR assays to detect mixed- MLO infections in a single host plant. Phytopathology, 84: 559-566. 21.Lee I.M., Davis R.E., Gundersen-Rindal D.E. 2000. Phytoplasma: Phytopathogenic mollicutes. Annual Review of Microbiology, 54: 221-555. 22. Lee I.-M., Gundersen-Rindal D., Davis R.E., Bottner K.D., Marcone C., Seemueller E. 2004.’Candidatus Phytoplasma asteris’, a novel taxon associated with aster yellows and related diseases. International Journal of Systematic Bacteriology, 54: 1037-1048. 23.Lorenz, K.-H., B. Schneider, U. Ahrens, and E. Seemu¨ller. 1995. Detection of the apple proliferation and pear decline phytoplasmas by PCR amplification of ribosomal and non ribosomal DNA. Phytopathology 85:771–776. 24. Maiti, S., Hegde, M.R. and Chattopadhyay, S.B. 1988. Handbook of Oil Seed Crops, 317 pp. Oxford and IBH Publishing Co. (Pvt.). Ltd, New Delhi. 25.Marzachi C. 2004. Molecular diagnosis of phytoplasmas. Phytopathology Mediterranean, 43: 228-231. 26.Sambrook, J., Fritsch, E.F. and Maniatis, T. 1989. Molecular cloning: a laboratory manual. New York: Cold SpringHarbour Laboratory Press. Sambrook Molecular cloning: A laboratory manual. 27. Schaff D.A., Lee I.-M., Davis R.E. 1992. Sensitive detection and identification of mycoplasma like organisms by polymerase chain reactions. Biochemistry Biophysics Research Communications, 186: 1503-1509. 28.Schneider, B., E. Seemu¨ller, C. D. Smart, and B. C. Kirkpatrick. 1995. Phylogenetic classification of plant pathogenic mycoplasma-like organisms or phytoplasmas, p. 369–380. In S. Razin and J. G. Tully (ed.), Molecular and diagnostic procedures in mycoplasmology, vol. 1. Academic Press, San Diego, Calif. 29.Silme, R.S. and M.I. Cagirgan. 2010. Screening for resistance to fusarium wilt in induced mutants and world collection of sesame under intensive management. Turk.J. Field Crops. 15(1): 89-93. 30.Smart, C.D., B. Schneider, C.L. Blomquist, L.J. Guerra and N.A. Harrison . 1996. Phytoplasmaspecific PCR primers based on sequences of the 16S-23S rRNA spacer region. Phytopathology, 62: 2988-2993. 31.Tan, A.S. 2010. Screening Phyllody Infected sesame varieties and seed transmission of phyllody under natural conditions in Turkey. Journal of Ayub Agricultural Research Institute. 20: 26-33.2348-8069https://t.ly/8JPn1MSA Google ScholarSesame (Sesamum indicum L.), family Pedaliaceae is one of the most ancient cultivated oilseed crops among the edible annual group in Egypt and all over the world. Phytoplasmas are pathogens of many plant species throughout the world including sesame causing a large variety of symptoms ranged from mild yellowing to death of infected plants. Symptomatic samples including green leaf-like floral organs, virescence, phyllody and proliferation were collected from infected sesame field in Giza Governorate. This research was undertaken to develop a diagnostic tool to identify phytoplasmas recently discovered infecting sesame in Egypt, and to classify them according to their phylogenetic group. Direct and nested PCR primers of 16S-23SrRNA gene, paired with phytoplasma universal primer followed by strain-specific PCR primers were used in this study. Spacer Region (SR) primers were employed for identification of Phytoplasma group associated with sesame symptoms. Results showed the presences of mixed infections of phytoplasma in the tested sesame samples which collected from the field with different type of Phytoplasma like symptoms. Results also indicated that polymerase chain reaction with primers from sequencing of 16S-32S rRNA and from SR opened new paths for research on phytoplasma identification and classification. Nested PCR has been applied to overcome problems related to sensitivity of phytoplasma detection, although this approach is more time consuming and subject to template. Unfortunately, nested-PCR also meets some difficulties: unspecific bands, false positives or negatives caused by DNA and contamination of single or nested PCR. Therefore, confirmation of PCR results by using different primer pair combinations (generic and group-specific) seems to be the way for correct phytoplasma identification in the examined sesameenPhytoplasma associatedPhyllodyPhytoplasma detectionPCR amplification.Specific primer,Universal primer,Phytoplasma detection,Sesame,Article