Lethal yellowing of coconut in Cuba: New findings

Lethal Yellowing of coconut (LY) is the most important disease affecting coconut production worldwide. In America, it is associated with the presence of ‘Candidatus Phytoplasma palmae’ strains. Symptomatic and asymptomatic coconut plants were surveyed in selected areas to detect and identify phytoplasmas associated with LY in Cuba. An ornamental palm (Pritchardia pacifica) and individuals of insect Hortensia similis were also collected to verify their possible role in maintenance and dissemination of this phytoplasma. Phytoplasmas enclosed in groups 16SrI, -VII and –XII were detected in symptomatic coconut plants, however the 16SrIV-A was the predominant subgroup. In RFLP analyses on groEl gene the 16SrIV-A phytoplasma detected in the only positive plant from Pilón resulted different from the others and identical to strains from Jamaica. P. pacifica and H. similis were positive to ‘Ca. P. palmae’ presence, however the cloned sequences of phytoplasmas from H. similis showed RFLP profiles consisted with those of the 16SrIV-A subgroup, while some of those from P. pacifica showed different profiles with AluI, HhaI and Sau3A enzymes. RFLP analysis on more amplicons from 16S rDNA confirmed the presence of 16SrIV-A phytoplasmas also in P. pacifica suggesting the presence of a possible mixed infection of diverse ‘Ca. P. palmae’ strains.