Molecular identification and characterization of ‘Candidatus Phytoplasma convolvuli’-related strains (representing a new 16SrXII-O subgroup) associated with papaya bunchy top disease in Nigeria

Beginning in 2018, a new papaya disease occurred Ibadan, Oyo State, Nigeria. Affected trees exhibited symptoms including excessive shoot proliferation at the top of crown, leaf mosaic and crinkling, dieback. The was designated as Nigerian bunchy (NGPBT) disease. Since most characteristic symptom it indicative phytoplasma infection, polymerase chain reaction (PCR)-based molecular diagnostic method employed this study. Phytoplasmas were detected diseased samples by semi-nested PCR using 16 S rRNA gene-specific primers. Subsequent determination analysis amplified gene sequences phylogenetic revealed that NGPBT phytoplasmas closely related to ‘Candidatus Phytoplasma convolvuli’ Stolbur (16SrXII) group. Virtual restriction fragment length polymorphism (RFLP) based on F2nR2 showed strains represented novel subgroup group, 16SrXII-O. This is first report Identification not only broadened genetic diversity group but also signaled an expansion group's geographic distribution. Notably, two previously reported associated with diseases Australia Taiwan belong 16SrXII exhibit similar It would be interesting learn how these three relate each other. Further in-depth study weed reservoirs insect vectors will contribute better understanding pathosystem epidemiology