استفاده از هورمون های گیاهی در به گشت علایم Candidatus Phytoplasma phoenicium در پروانش

Plant hormones have important roles in activation of plant defensive system by regulation of transcription of its relevant genes. Also, phytoplasms generate yellows, little leaf, virescence and stunting symptoms by induction of hormone imbalances. To study roles of hormones in recovery of phytoplasma symptoms, Candidatus Phytoplasma phoenicium was transmitted from infected black locust trees to healthy periwinkle plants by dodder and six weeks post inoculation yellows, shorter internodes and phyllody was observed in periwinkle plants. Contamination of the periwinkle plants were confirmed by nestes PCR using phytoplasma specific primers. Solution of 60 mM indol-3-butyric acid or 0.2 mM gibberellic acid was sprayed on the infected periwinkles. Three weeks later, yellows and stunting in the gibberellic acid treated periwinkles were recovered and new flower developed, but no changes were observed in the auxin treated plants. The total chlorophyll content in gibberellic acid treated plants were increased up to 38% with significant difference from the control plants, but in the auxin treated plants no significant difference was observed. Also, gibberellic acid level in the treated plants increased 24% which was significantly different from the control plants. Moreover, activity of phenylalanine ammonia-lyase in the gibberellic acid treated plants was increased up to 25% as compared to the infected plant. Despite the symptoms recovery, the phytoplasma was detected in the treated plants by nested-PCR. The results revealed that by regulating gibberellic acids level in plant, phytoplasma induce phyllody and stunting in the infected periwinkle. Application of gibberellic acid regulated activity of the genes involve in phenylpropanoid pathway that increased activity of phenylalanine ammonia-lyase in the infected plants. These changes had led to recovery of the phytoplasma symptoms in the infected periwinkle plants.