PCR-detection of Synchytrium endobioticum (Schilb.) Perc.

摘要

The ITS-DNA region of Synchytrium endobioticum (Schilb.) Perc., the causal agent of potato wart disease, was used to generate specific PCR primers for molecular diagnosis of the disease. DNA was extracted from wart galls of all S. endobioticum pathotypes (1, 2, 6, 18) currently occurring and used for official testing purposes in Germany. Using the universal ITS primer # 4 and the S. endobioticumspecific primer Kbrl, a PCR fragment of 543 bp was obtained from all four fungal pathotypes. DNA for PCR-based diagnosis of the fungus could be extracted easily from summer sori, however, we did not succeed to extract amplifiable DNA from resting sori found in contaminated soils. To circumvent this problem, zoospores emerging from resting sori were used for DNA extraction and indirect detection. PCR also allowed to discriminate between weakly resistant and moderately susceptible responses of potato cultivars in addition to the routine visual inspection, since only alive summer sori of the weakly susceptiblereacting potato cultivars released quantities of zoospores sufficient to be detected. No PCR signal was obtained from weakly or completely resistant potato cultivars.