Phytoplasmas have been associated with a disease that affects trees of at least 11 species from different botanic families in Bogotá, Colombia. ‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma fraxini’ are the major groups of phytoplasma in the area of Bogotá. In this study, the genetic diversity within ‘Ca. P. asteris’ and ‘Ca. P. fraxini’ was studied in five urban tree species: Croton species (Euphorbiaceae), Fraxinus uhdei (Oleaceae), Magnolia grandiflora (Magnoliaceae), Populus nigra (Salicaceae) and Quercus humboldtii (Fagaceae). Analyses of the 16S rRNA gene using nested PCR, RFLP and sequencing showed that phytoplasmas of ‘Ca. P. asteris’ could be assigned to: subgroup 16SrI-B; a new subgroup named 16SrI-AF, with a restriction pattern similar to that of 16SrI-B; and a new subgroup named 16SrI-AG, with a restriction pattern similar to that of 16SrI-K and 16SrI-AH with a restriction pattern similar to that of 16SrI-AC. ‘Ca. P. fraxini’ isolates belonged to a new subgroup named 16SrVII-G, with a restriction pattern similar to that of 16SrVII-A. To complement the identification of the phytoplasma strains, we amplified nonribosomal genes such as leuS and secA. Unexpectedly, it was observed that in 16 trees in which 16S rRNA gene analysis showed the presence of ‘Ca. P. fraxini’ only, the leuS or secA primers amplified sequences exclusively affiliated to ‘Ca. P. asteris. In those plants, sequences belonging to ‘Ca. P. fraxini’ leuS or secA genes were not amplified. The present work contributes to the identification of novel strains of both species in Colombia, and supports previous suggestions that phytoplasmas in South America are highly variable.

La presencia de fitoplasmas del grupo 16SrI (‘Ca. Phytoplasma asteris’) fue reportada en Croton spp. (Eu­phorbiaceae), Pittosporum undulatum (Pittosporaceae) y Populus nigra (Salicaceae), en Bogotá. En este traba­jo se reporta la existencia adicional de fitoplasmas del grupo 16SrVII ‘Ca. Phytoplasma fraxini’ en estas mismas especies de árboles ornamentales, por técnicas moleculares como PCR anidada, RFLP y secuenciación del gen 16SrRNA. Los resultados muestran la existencia de un complejo de fitoplasmas de los grupos 16SrI y 16SrVII que se asocian con síntomas como deformación general de la corona, ramas en copo, amarillamiento, elonga­ción anormal de brotes apicales, escobas de bruja y rebrotación epicórmica que afectan el estado de sanidad de los árboles. En diciembre de 2013 la prevalencia sintomática en Croton spp., P. undulatum y P. nigra y se estimó en 36%, 93% y 85% respectivamente. Este trabajo presenta evidencia de que plantas de familias dife­rentes a Oleaceae que son susceptibles a fitoplasmas del grupo 16SrVII y que en este caso se encuentran en infecciones mixtas con fitoplasmas del grupo 16SrI. Se presentan evidencias de una enfermedad emergente de alta prevalencia en estas especies de árboles han pasado desapercibidas hasta la fecha, pero suponen un riesgo para la supervivencia de los árboles urbanos en Bogotá.

The leafhoppers (Cicadellidae) are a diverse and cosmopolitan group of Hemiptera that feed on plants, and occasionally cause losses due to the direct damage they inflict to their hosts, or by transmission of viruses and phytoplasmas. Phytoplasmas are plant pathogenic bacteria that can adversely affect many plant families. In the Sabana de Bogotá, Colombia, several species of urban trees, potatoes, and strawberry crops are affected by phytoplasma diseases. The family Cicadellidae contains the largest number of known vectors of phytoplasmas, but in Colombia, knowledge of their biology is scarce. The objective of this work was to characterize the diversity of Cicadellidae associated with kikuyu grass Cenchrus clandestinus (Hochst. ex Chiov.) Morrone (Poaceae) in the grasslands of the Sabana de Bogotá, at an urban site of the Universidad Nacional de Colombia and a semirural site at the Universidad Militar Nueva Granada, located in Bogotá and Cajicá, Colombia, respectively. Species richness, abundance, and cicadellid dominance were compared for the 2 sampling sites, using alpha and beta diversity estimators. In total, 3,334 leafhoppers were collected, represented by subfamilies Deltocephalinae (82.3%), Cicadellinae (15.8%), Aphrodinae (1.2%), Iassinae (0.6%), Idiocerinae (0.03%), and Typhlocybinae (0.03%). Of the 15 leafhopper species present, 6 were identified to the species level. DNA barcodes were established for 12 morphotypes, including 6 species and 6 superior taxa by amplification of the COI gene. In both locations, the sampling effort was deemed insufficient. Species richness at Universidad Militar Nueva Granada was greater (n = 13) than at Universidad Nacional de Colombia (n = 10), but abundance was higher at Universidad Nacional de Colombia (n = 1,982) than at Universidad Militar Nueva Granada (n = 1,352). The 2 most abundant species were Amplicephalus funzaensis Linnavuori and Exitianus atratus Linnavuori (both Hemiptera: Cicadellidae), both recorded as vectors of phytoplasmas. Other common leafhopper species in collections were Haldorus sp. and Dalbulus sp. (both Hemiptera: Cicadellidae) and are considered possible phytoplasma vectors. Because C. clandestinus is host to several cicadellid species, it may play an important role in the epidemiology of phytoplasma transmission in the Sabana de Bogotá.