Emerging phytoplasma threat: Plum orchards under siege in Himachal Pradesh, India

Plum is considered to be one of the most important deciduous stone fruits of the temperate region belonging to the family Rosaceae and the genus Prunus. Plum trees exhibiting different symptoms like necrosis, stunting, yellowing, leaf reddening, severe inward longitudinal rolling of leaves, brittle leaves, abnormal thickening of the midribs and primary veins which produce tiny chlorotic leaves were collected. DAPI staining was done, and total DNA was extracted from infected samples and analyzed by PCR using the phytoplasma universal primer pairs P1/P7 followed by nested PCR with primer pairs R16F2n and R16R2. The results indicated that the symptomatic plum trees are infected with ‘Candidatus Phytoplasma ziziphi’ strains. This is the first report of this phytoplasma in plum in India.