Elimination of ‘Candidatus Phytoplasma asteris’ from rose (Rosa × hybrida L.) by application of antibiotics under in-vitro and in-vivo conditions

Rose is severely affected by phytoplasma diseases, causing significant loss in flower quality. A valid control strategy is not yet available for managing phytoplasma diseases in roses. The present study aimed to obtain phytoplasma-free rose plants using antibiotics. In this study, phytoplasma-associated rose cultivar ‘Dr. M. S. Randhawa’ exhibiting phyllody and flower malformation symptoms was used to study the effect of three antibiotics namely, oxytetracycline, streptomycin and erythromycin A at different concentrations (60 mg/L, 80 mg/L and 100 mg/L) for management of phytoplasma under in-vitro and in-vivo conditions. All concentrations of oxytetracycline effectively eliminated phytoplasma in both conditions. The absence of phytoplasma was confirmed by nested Polymerase Chain Reaction (PCR) analysis in all treated plants in-vivo and in-vitro at monthly intervals for up to three months. However, streptomycin and erythromycin A treatments failed to eliminate phytoplasma in both conditions, as indicated by positive PCR results. The findings of this study reveal that oxytetracycline at 60 mg/L was the most efficient in eliminating phytoplasma from infected rose plants under both in-vitro and in-vivo conditions.