Characterization of an isolate of ‘Candidatus Phytoplasma asteris’ infecting Zinnia elegans in India

Different gardens and nurseries were surveyed in various locations of Gorakhpur of Eastern Uttar Pradesh, India during 2008–2009 to verify incidence of phytoplasma disease. Typical little leaf, chlorosis, witches’ broom, yellowing and phyllody symptoms were observed on Zinnia elegans plants growing in gardens of Sugarcane Research Station, Kunraghat, Gorakhpur of Uttar Pradesh, India. The symptomatic plants were further processed for phytoplasma detection and characterization. Universal primer pair of P1/P7 amplified the 1.7 kb DNA fragment of phytoplasma 16S-23S rRNA from nucleic acid extracted from two symptomatic Z. elegans plants. In nested PCR assay with R16F2n/R16R2 a DNA fragment of ~1.2 kb was obtained. Neither by direct nor by nested PCR amplification was present from any non-symptomatic plant. Sequencing and BLAST analysis of 1.2 kb amplicon of the phytoplasma DNA revealed 99% sequence identity with the 16SrRNA of ‘Candidatus Phytoplasma asteris’ (16SrI) group strains and phylogenetic analysis confirmed this results. This is the first report of ‘Ca. P. asteris’ associated with yellowing, witches’ broom and little leaf disease of Zinnia elegans in India.