AMPLIFICATION OF SPECIFIC RIBOSOMAL AND NON-RIBOSOMAL PHYTOPLASMA DNA CAN SERVE TO DIAGNOSE THEIR PRESENCE AT APPLE AND PLUM TREES FROM KORCA PLANTATIONS

Korca is one of the main areas of apple cultivation in Albania, where the early and reliable diagnosis of phytopathologies such as those caused by MLO is important. Until recently, main detection system was based on symptomatology, but considering that sometimes infections are asymptomatic, that there is lack of phytoplasma epidemiology, the lack of full knowledge on phytoplasma etiology of particular diseases, and the fact that their detection depends widely on their titer in floem tissue, importance should be given on DNA based methods of detection. Present study analyses the presence of phytoplasmas at six collections of apple and plums in Korca district, Albania (four apple varieties and two plum varieties). Samples of categories root, stem, trunk and leaves were used to extract phytoplasmal DNA based on the enrichment protocol of Kirkpatrick et al., (1987) and Doyle & Doyle, (1990). Four primer pairs, three ribosomal specific and one non-ribosomal specific designed according to Schneider & Seemuller (1993) were used to amplify target DNA. Specific amplifications of phytoplasma gene fragments showed that two of the ribosomal specific primer pairs could amplify 100% of target sequences; the PD specific primer pair failed to detect all samples (40% only), and the non-ribosomal specific pair failed to amplify from any of the samples. In order to identify the possible phytoplasma strains present at samples from Korca region, suspected because of the double products of amplification in some cases, the RFLP methodology could be the method of choice.