Actualización de aspectos claves para la epidemiología del amarillamiento letal del cocotero en Cuba

Introduction: Lethal yellowing of coconut constitutes one of the main challenges in the Caribbean region. Objectives: To characterize the diversity of phytoplasmas associated with the observed symptom of lethal yellowing in Cuban coconut ecosystems; to characterize the lethal yellowing-associated phytoplasmas detected in alternative hosts and potential insect vectors; to verify the transmission of lethal yellowing-associated phytoplasmas by the identified potential insect vectors. Methods: The characterization of lethal yellowing-associated phytoplasmas detected in coconut as well as in alternative plant host and potential insect vector were characterized by PCR-RFLP analysis, sequencing and phylogeny. Experimental transmission tests were carried out using adults of Haplaxius crudus collected on symptomatic plants in coconut plantations. Results: The subgroup 16SrIV-A was predominant in symptomatic coconut plants. However, phytoplasmas of ribosomal groups 16SrI,-VII and –XII were also detected for the first time in coconut within the affected areas. The use of the groEL gene allowed discriminating different isolates in the Cuban populations of the 16SrIV-A according to their geographical origin. For the first time, the detection and characterization of phytoplasmas infecting Pritchardia pacifica and Hortensia similis evidenced it as alternative plant host and as potential vector of Candidatus Phytoplasma palmae isolates, respectively. The successful experimental transmission confirmed Haplaxius crudus as a vector of Ca. P. palmae isolates. Conclusions: These new epidemiological aspects highlight the complexity of the pathosystem in Cuban conditions and are fundamental for the improvement of its management.