Detection and molecular characterization of phytoplasmas in mango seedlings

Samples were collected from seedlings of mango varieties Amprapali and Dashehri showing symptoms of witches’ broom in India. The disease incidence resulted up to 30% in a commercial fruit nursery at Ayodhya, Uttar Pradesh, therefore the presence of phytoplasmas was verified. Three diverse phytoplasmas were preliminary detected by PCR/RFLP analyses on the 16S ribosomal gene resulting enclosed in groups 16SrI, 16SrII and 16SrVI. Further amplification on imp, sap, rp and clp DNA fragments located outside the phytoplasma chromosomal region allowed the 16SrII strain characterization and confirmed its clustering with ‘Candidatus Phytoplasma australasia’ strains. The presence of diverse phytoplasmas in mango seedlings from a nursery indicate the high risk of using phytoplasma infected materials for the new plantation materials. However, the possibility of the phytoplasma identity tracking by multigene analyses may help in elucidating their dissemination in the orchards by insect vectors and/or other agricultural practices.