Molecular evidence of Taphrina wiesneri in leaves and buds of healty sweet cherry (Prunus avium) A possible endophytism?

Analysis of DNAs from leaves and buds of several sweet cherry trees (Prunus avium) in two different Italian regions with different climates, has revealed the presence of Taphrina wiesneri, in all samples analyzed. The presence of other fungi was only occasional. The presence of T wiesneri was shown by sequencing segments of rDNA genes amplified by PCR. Analysis of genes coding for the elongation factor-1 alpha (EF1-alpha) and RNA-polymerase II subunit 1 (RPB1), confirmed the result. The T wiesneri sequences were variants of those reported in data bases. T wiesneri was not detected in buds of walnut, apricot and sour cherry growing close to the analysed sweet cherry trees. Determination of the relative numbers of T wiesneri and sweet cherry genomes in samples prepared from the same buds of 4 different trees all gave similar values indicating massive presence of the fungus. However, in situ hybridization experiments on bud sections using a T wiesneri-specific 18S rDNA probe and stains for fungi, labelled structures not clearly representing hyphae.