Molecular characterization confirming phytoplasma association with spear rot disease of oil palm in India

Abstract

Oil palm is grown in 0.179 million ha of 11 states of India. Among the diseases reported, spear rot disease (SRD), endemic to the plantations in the state of Kerala and with sporadic incidence in Sullia district of Karnataka, is the most important. Characteristic symptoms recorded were chlorosis of the youngest whorl of fronds, rotting of spear and reduction in the frond size. The affected palms succumb within five years from manifestation of symptoms. Phytoplasma presence was earlier reported based on phytoplasma detection in affected palms by electron microscopy observations, dodder transmission of the agent from diseased to healthy palms, and symptom reduction after oxytetracycline treatments. In the present study, molecular characterization by using universal phytoplasma specific primers based on 16S rRNA gene sequence confirmed the phytoplasma association with the disease. Sequence comparison and phylogenetic analysis revealed the association of 16SrXI group phytoplasmas with spear rot disease, first report in oil palm in the world.