Investigations with real time PCR assay on the trasmissibility of pear decline phytoplasma (PDP) with dormant buds.

A study was carried out to determine the possibility to transmit the PD agent through grafting with dormant buds collected from naturally infected trees, due to winter degeneration of the sieve tubes of the above ground part of pear trees. A real time PCR procedure for PDP detection was set up with a multiplex assay where host and pathogen DNA can be amplified simultaneously to distinguish between uninfected plant material and false negative results due to PCR inhibition. Real time pCR assays were performed on 92 seedlings of Pyrus communis (cv. A. fetel, Conference and William grafted on P. communis rootstocks) one year after grafting with dormant buds. resulted PD-positive after PCR analysis. No phytoplasmas were detected in the 92 grafted seedlings; the results suggested that in our conditions PDP is not trasnmissible with dormant buds to healthy trees.