Association of a 16SrII group phytoplasma with dieback disease of papaya in India

During surveys, papaya plants showing dieback symptoms with yellowing and necrosis of leaves were collected from the Sugarcane Research Station campus, Gorakhpur, Eastern Uttar Pradesh, India in September 2010. DNA was extracted from infected and healthy plants and indexed in nested PCR with phytoplasma generic primers P1/P7 and R16F2n/R16R2. Nested PCR amplicons of 1.2 kbp were obtained from dieback symptomatic papaya samples. Following RFLP analysis, infected papaya samples exhibited identical HaeIII and RsaI profiles, which were typical of a 16SrII phytoplasma. None of the healthy papaya samples evaluated was found positive for the phytoplasmas. The amplification with phytoplasma primers and their RFLP profiling suggests that the dieback phytoplasma associated with papaya in India is a phytoplasma member of the 16SrII group ('Candidatus phytoplasma aurantifolia'). This is the first record of this phytoplasma associated with dieback disease of papaya in India.