Association of phytoplasmas with a chestnut yellows in Italy

The correlation between a chestnut yellow leaves disorder and the presence of phytoplasmas was verified in European chestnut trees showing yellow leaves, necrosis and leaf rolling, witches’ broom formations, dwarfism, abortion of the inflorescences and in some cases death of the plant. Molecular analyses were performed by PCR analyses on samples collected in the Emilia and Marche Apennines (Italy) from the end of June and the end of September. In the samples from Marche Apennines the phytoplasma presence was detected in almost all the plants sampled was thus allowing to associate them with the observed symptomatology. The results of PCR analyses on the samples from the Emilia Apennines carried out after a particularly hot and dry period, suggest that the symptomatology observed is due to a complex of causes, where infections associated with phytoplasmas and pedoclimatic factors play a role. The RFLP analysis showed that the phytoplasmas detected within the sampled plants belong ribosomal group 16SrI (aster yellows) and subgroup 16SrXII-A (“stolbur”). This represents the first molecular detection of phytoplasmas in European chestnut trees.