Molecular and biological characterization of ‘Candidatus Phytoplasma aurantifolia’ strains infecting commercial citrus species in Iran

Abstract

In a 2017 survey, witches’ broom disease (WBD) of Mexican lime (WBDL), Bakraee (WBDB), grapefruit (WBDGF), Kinnow (WBDK), Orlando tangelo (WBDOT), Minneola tangelo (WBDMT), sweet oranges varieties Valencia (WBDVSO) and a local (WBDLoSO) were observed in the Hormozgan province of Iran. The agents of citrus WBD were graft transmitted to lime seedlings and from lime seedlings to periwinkle plants via dodder. The work revealed that disease symptoms in lime seedlings and periwinkle plants are biological features for differentiating 16SrII-B and 16SrII-C strains. Phylogenetic and Tsp509I enzyme virtual RFLP analyses and presence of the ‘Candidatus Phytoplasma aurantifolia’ (16SrII-B) signature revealed that phytoplasmas detected in the present study and those from WBDVSO, WBDOT and WBD of citron (Kerman province, Iran) previously reported as 16SrII-C phytoplasma strains, are members of 16SrII-B subgroup. WBDK, WBDOT, WBDMT, WBDVSO and WBDLo association with 16SrII-B phytoplasmas is reported for the first time in the world.