First Report of Witches'-Broom Disease of Sesame (Sesamum indicum) in Oman

Abstract

Sesame is the major oil seed crop in Oman. During 2004, disease symptoms were observed at Nizwa, 175 km south of Muscat. Symptoms included phyllody and excessive development of short shoots and internodes resulting in little leaves. Total genomic DNA was extracted from healthy and symptomatic plants with a modified cetyltrimethylammoniumbromide (CTAB) buffer method (2). DNA samples were assayed by polymerase chain reaction (PCR), with the 16S rDNA amplified using primers P1 and P7. Direct PCR products were used as template DNA for nested PCR with primers R16F2n and R16R2. Direct PCR products were analyzed by restriction fragment length polymorphism (RFLP) with four restriction enzymes, Tru9I, HaeIII, HhaI, and RsaI. DNAs from alfalfa and lime plants infected by witches'-broom phytoplasmas were used as positive controls and DNA from healthy plants and water were negative controls. The results showed the presence of a 1.8-kb product amplified with the direct PCR and a 1.2-kb product of the nested PCR from infected sesame and the positive controls. No PCR product was observed in the negative control. The PCR assay confirmed the presence of phytoplasma causing witches'-broom disease in sesame. The RFLP results showed the sesame phytoplasma to be most similar to the alfalfa phytoplasma, a member of 16SrII group (1). To our knowledge, this is the first report of a phytoplasma of the 16Sr II group causing witches'-broom disease on sesame in the Sultanate of Oman. References: (1) A. J. Khan et al. Phytopathology 92:1038, 2002. (2) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA, 81:8014, 1984.

Phyllody Phytoplasma infecting Sesame (Sesamum indicum) in Myanmar

“…This disease was reported previously in Israel (Klein, 1977), Oman (Al-Sakeiti et al, 2005), Thailand , Pakistan (Akhtar et al, 2008) and Turkey (Sertkaya et al, 2007). However, sesame witches' broom phytoplasma of Oman, and sesame phyllody phytoplasmas of Pakistan and Thailand have been assigned to a different phytoplasma group, peanut witches' broom group (AlSakeiti et al, 2005;Akhtar et al, 2008).…”

“…P. trifolii' (Sertkaya et al, 2007). Therefore, classification of phyllody phytoplasma associated with sesame has been attributed to at least three distinct strains worldwide including aster yellows, peanut witches' broom and clover proliferation group (Al-Sakeiti et al, 2005;Khan et al, 2007). This study represents the first evidence of phytoplasma association with phyllody affected sesame plants related to 'Ca.…”

First report on the association of a 16SrII phytoplasma with sesame phyllody in Pakistan

“…The disease causes significant losses in Pakistan (Sarwar et al ., 2006) but prior to this report the causal agent had not been identified. However, in Oman, phytoplasmas of the 16SrII group have been reported as the causal agent of sesame phyllody (Al‐Sakeiti et al ., 2005).…”

Association of two groups of phytoplasma with various symptoms in some wooden and herbaceous plants

“…Sesame plants affected by phytoplasma showed symptoms of floral virescence, phyllody, stem fasciation, shortened internodes and cracking of seed capsules (Figure j). Sesame phyllody has been reported to be caused by different groups of phytoplasma, that is group 16SrI in India (Khan, Raj, & Snehi, ), Myanmar (Win, Back, & Jung, ) and South Korea (Lee et al., ); group 16SrII in India (Pamei & Makandar, ), Iran (Esmailzadeh‐Hosseini, Mirzaie, Jafari‐Nodooshan, & Rahimian, ), Oman (Al‐Sakeiti, Al‐Subhi, Al‐Saady, & Deadman, ), Pakistan (Akhtar et al., ), Taiwann (Tseng, Deng, Chang, Huang, & Jan, ), Thailand (Martini et al., ) and Turkey (Ikten et al., ); group 16SrVI in Turkey (Sertkaya, Martini, Musetti, & Osler, ); group 16SrIX in Iran (Salehi, Heydarnejad, & Izadpanah, ) and Turkey (Catal, Ikten, Yol, Ustun, & Uzun, ); and subgroup 16SrIX–C in Turkey (Ikten et al., ).…”