Molecular identification and characterization of phytoplasmas causing stolbur disease in potato and tomato plants in Turkey

For a long time, stolbur-like diseases have had devastating effects on the yield and quality of potato production in Eastern (Erzurum) and Southern (Akcakale-Sanliurfa) Anatolia, tomato production in the Marmara region of Turkey. For this study, tomato, potato and various other plants were collected from infected fields and surroundings. Nested polymerase chain reactions (PCR) carried out by using phytoplasma universal primer pair P1/P7 followed by R16F2n/R16R2, amplified expected size fragments (F2nR2) from DNA templates derived from symptomatic plants. The F2nR2?s were cloned, sequenced and analyzed on iPhyClassifier. Collective RFLP patterns of F2nR2?s differed from digestion profiles of previously described 16SrXII subgroups, sharing a best similarity coefficient of 0.94 for potato-associated and 0.97 for tomato-associated phytoplasmas with the reference phytoplasma strain of subgroup 16SrXII-A. Thus, both phytoplasmas should represent new 16SrXII subgroups. Furthermore, new primer sets were developed for priming specific PCR-amplification of phytoplasma 16S rDNA sequences and successfully used in revealing alternative phytoplasma plant hosts. These primer sets will help to determine possible alternative hosts and vectors of stolbur phytoplasmas in Turkey, which is important for development of an integrated management strategy for effective control of this disease in the future.