The decline and death of Canary Island date palms in México City is associated with subgroup 16SrIV-D phytoplasmas

The Canary Island date palm (Phoenix canariensis) is one of the most representative tree species of the urban landscape of México City. However, since the last decade, severe foliar damage and decay has been observed, causing the death of hundreds of individuals in different boroughs of the city’s north zone. The symptoms observed in these affected palms were indicative of Texas Phoenix palm decline (TPPD), a serious disease associated with phytoplasmas of the 16SrIV-D subgroup. In this study, the use of nested-PCR and real-time PCR detected the presence of phytoplasmas of group 16SrIV in 21 out of 25 Canary Island date palms located in the Miguel Hidalgo, Benito Juárez, and Cuauhtémoc boroughs of México City. Sequencing the F2nR2 fragment of the 16S rRNA gene generated from the phytoplasma DNA samples of six positive palms, and subsequent in silico analysis, revealed that these phytoplasmas belonged to the 16SrIV-D subgroup. The presence of this phytoplasma strain in México City extends the range of known climates in which this pathogen and its vectors are capable of subsisting, in addition to evidencing an increase in the geographical distribution of this pathogen in recent years.