CLASSIFICATION OF THE SESAME PHYTOPLASMA STRAINS IN INDIA AT THE 16SR SUBGROUP LEVEL
Madhupriya, G.P. Rao, A. Kumar, V.K. Baranwal
During 2011-2013, 7-55% incidence of sesame phyllody and witches' broom symptoms were observed on sesame plants in nine states of India. Seventeen sesame symptomatic samples were analyzed by polymerase chain reaction with phytoplasma specific primers, amplifying 16S rRNA and secA genes. Pairwise sequence comparison and phylogenetic analyses of 16S rRNA and secA gene sequences classified them with aster yellows (16SrI) and peanut witches’ broom (16SrII) phytoplasma groups. Further virtual RFLP analysis of 16S rDNA sequences allowed finer classification of the sesame phytoplasma strains into 16SrI-B, 16SrII-C and 16SrII-D subgroups. 'Candidatus Phytoplasma asteris' of the subgroup 16SrI-B was present in sesame plants in two states viz., Uttar Pradesh and West Bengal, while 16SrII-C subgroup phytoplasma was found in sesame plants grown in four states viz., Uttar Pradesh, Madhya Pradesh, Chhattisgarh and Rajasthan. Phytoplasma belonging to 16SrII-D subgroup was found as the most widely distributed phytoplasma strain on sesame from five states viz., Delhi, Rajasthan, Gujarat, Tamil Nadu and Maharashtra. This is the first report of subgroup level classification of phytoplasma strains from sesame in India.