Abstract
ABSTRACT: Sesame (Sesamum indicum L.) plants exhibiting symptoms of phyllody disease were observed in commercial fields in Paraguay. The symptoms were indicative of infection by phytoplasmas. Thus, the present study investigated the association between affected plants and phytoplasma, which was later analyzed using molecular and phylogenetic methods. Total DNA was extracted from symptomatic and asymptomatic plants and used in nested PCR assays using primers R16SN910601/R16SN011119 and R16F2n/16R2. Amplified products of 1.2 Kb revealed the presence of phytoplasma in all diseased plants, and electron microscopy confirmed the presence of phytoplasmas within phloem vessels. Nucleotide sequences from sesame phytoplasma shared 99 % similarity with phytoplasmas belonging to group 16SrI. Computer-simulated RFLP indicated that the detected phytoplasma is representative of the 16SrI-B, therefore, a ‘Candidatus Phytoplasma asteris’-related strain. Phylogenetic analysis was in agreement with virtual RFLP. Our findings expand the current knowledge regarding distribution of representatives of the aster yellows group in a new agroecosystem and implicate sesame as a new host of 16SrI-B phytoplasma in Latin America.
Highlights
Phytoplasmas are cell wall-less bacteria that inhabit the phloem, are naturally transmitted by sucking insects, and are associated with diseases occurring in numerous crops (Lee et al, 2000)
Phyllody was first reported in a province of Pakistan in 1908 (Vasudeva and Sahambi, 1955) and for many years, it was regarded as a viral disease (Weiss et al, 1983; Turkmenoglu and Ari, 1959)
Preliminary identification of the phytoplasma was performed using product generated by primers R16SN910601/R16SN011119 as a template for further PCR assays conducted with the group-specific primers R16(I)F1/R16(I)R1 (Lee et al, 1994), which are specific for identification of phytoplasmas belonging to group 16SrI
Summary
Phytoplasmas are cell wall-less bacteria that inhabit the phloem, are naturally transmitted by sucking insects, and are associated with diseases occurring in numerous crops (Lee et al, 2000). ABSTRACT: Sesame (Sesamum indicum L.) plants exhibiting symptoms of phyllody disease were observed in commercial fields in Paraguay. Amplified products of 1.2 Kb revealed the presence of phytoplasma in all diseased plants, and electron microscopy confirmed the presence of phytoplasmas within phloem vessels.
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