ISHS Acta Horticulturae 781: XX International Symposium on Virus and Virus-Like Diseases of Temperate Fruit Crops - Fruit Tree Diseases
MOLECULAR IDENTIFICATION OF PHYTOPLASMAS IN CULTIVAR COLLECTION AND PRODUCTION PLANTATIONS OF APPLE AND PEAR TREES IN THE CZECH REPUBLIC |
| Authors: | J. Fránová, K. Petrzik, F. Paprštein, J. Kučerová, M. Růžičková |
| Keywords: | apples, pears, phytoplasmas, PCR, RFLP, sequencing |
| Abstract:
During early summer and autumn 2005, surveys were conducted in apple and pear production plantations and cultivar collection in the Research and Breeding Institute of Pomology, Holovousy (East Bohemia). A total of 14 pear and 14 apple trees having symptoms of branch proliferation, dwarf, premature leaf reddening and also asymptomatic trees were tested for the presence of phytoplasmas. Nested PCR procedures were employed with different sets of primers to amplify phytoplasma 16SrDNA plus spacer region. The identity of PCR products was confirmed by RFLP analyses. Among the plants tested 7 pear and 7 apple trees were positive in nested PCR. Phytoplasmas belonging to apple proliferation group, subgroup 16Sr X-C and 16Sr X-A were identified in 6 pear and 3 apple trees, respectively. RFLP analyses of phytoplasma 16Sr DNAs (R16F2/R16R2 nested PCR products) from 2 apple and 1 pear trees after digestion with endonuclease MseI is very similar to profile of phytoplasmas belonging to 16SrI-C subgroup. However, fourth band (208 bp) is missing in the case of both apples and third band (235 bp) is not present in the profile from pear tree. A mixed infection of phytoplasmas belonging to 16SrX together with 16SrI group and 16SrI-B subgroup was identified in two different apple trees, respectively. Fourteen trees (7 pears, 7 apples) were negative for phytoplasma presence. Experiments involving phytoplasma DNA sequencing from selected samples and its comparison with the data available the GenBank confirmed the phytoplasma presence of 16Sr X-A, 16Sr X-C and 16Sr I-C subgroups which type strains are apple proliferation, pear decline and clover phyllody phytoplasmas, respectively. | |
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