Phytoplasma Associated with Yellowing Disease of Washingtonia sp. in Kuwait

Yellowing disease of palms caused by phytoplasma is spreading in the Arabian Gulf region. Surveys were conducted to determine the occurrence of the disease. Electron and fluorescence microscopy, and polymerase chain reaction (PCR) techniques were used to detect the phytoplasma associated with the yellowing disease of ornamental palm Washingtonia sp. grown in Kuwait. An accumulation of phytoplasmal DNA was observed by fluorescence microscopy in phloem tissues of diseased palms. Electron microscopy showed that phytoplasma cells were primarily confined to the phloemsieve elements of tissue samples collected from infected mature palms in the field. The pathogen was identified on the basis of molecular analysis using universal and specific nested primers in PCR amplifications. Prokaryotic 16S rDNA gene was detected in amplified PCR products. Nested PCR resulted in DNA amplification of 1.2 kbp fragment. This is the first report of a phytoplasmal rDNA gene identified from the putative causal pathogen of yellows in ornamental palms in the Arabian Gulf region.