Characterization and genetic diversity of phytoplasmas associated with elephant foot yam (Amorphophallus paeoniifolius) in India

During the growing season of 2015 and 2016, leaf yellowing, stunting, and declining symptoms were observed on elephant foot yam in three states of India.The 1.3 kb 16S rDNA fragments were amplified from genomic DNA extracted from all the symptomatic elephant foot yam samples in nested PCR assays using primer pairs, P1/P7 followed by 3F/3R. Pair wise sequence comparison, virtual RFLP and phylogenetic analysis of 16S rRNA gene sequences confirmed association of ‘Candidatus Phytoplasma trifolii’ (16SrVI-D) and ‘Candidatus Phytoplasma oryzae’ (16SrXI-B) related strains in Uttar Pradesh, Uttarakhand and Tripura states, respectively. To our knowledge, this is the first report of association of ‘Ca. P. trifolii’ and ‘Ca. P. oryzae’ related strains in elephant foot yam in world. In the present study, we also reported Datura stramonium showing witches' broom as a natural weed host for ‘Ca. P. trifolii’ phytoplasma in Gorakhpur and Kushinagar districts of Uttar Pradesh state, India.