Coffee crispiness and nogal cafetero witches’ broom associated with ‘Candidatus Phytoplasma pruni’-related strains in Colombia: multilocus gene characterization

Coffee is among the most important cultivated crops in Colombia, where it is frequently shaded with nogal cafetero, a tree species also used for timber and reforestation programs. Since 1998 severe cases of phytoplasma-related symptoms were observed in coffee plantations, and starting on 2002 also in nogal cafetero. Both diseases were associated to 16SrIII phytoplasma presence and different strains from coffee and nogal cafetero were identified having 99% of homology between them and to several 16SrIII strains in the 16S ribosomal gene. RFLP profiles of ribosomal protein gene and elongation factor indicate the presence of differentiable strains in a coffee sample, one of which is the prevalent in nogal cafetero. These results indicate a complex disease aetiology involving more phytoplasma strains in the two studied plant species.