First report of phytoplasma presence in a phyllody disease of buckwheat

Buckwheat is an ancient herbaceous pseudocereal crop belonging to Polygonaceae family which occupy a crucial part of the human diet and is consumed globally. Typical symptoms of a phytoplasma disease were collected from buckwheat grown during October 2019 with a disease incidence of 10 to 15% in an experimental field at University of Agricultural Sciences, GKVK, Bengaluru, India. Symptomatic and asymptomatic plant samples were collected, and the DNA was extracted using a CTAB method. A nested-PCR assay was used to amplify the 16S rRNA region of phytoplasmas with the primer pairs P1/P7 and R16F2n/R16R2. All the symptomatic plants and the positive control produced an expected amplicon size of about 1.2-kb, but no products were obtained from the asymptomatic plants. PCR products were cloned and sequenced from both ends. BLASTn analysis of 16S rDNA sequence showed 99.49% nucleotide identity with ‘Candidatus Phytoplasma australasiae = australasiaticum’. This is the first report of phytoplasma presence in buckwheat.