IDENTIFICATION OF Cercospora beticola ISOLATES, THE CAUSAL AGENT OF CERCOSPORA LEAF SPOT DISEASE OF SUGAR BEET, USING SPECIES-SPECIFIC PRIMERS

Cercospora leaf spot, caused by Cercospora beticola, is one of the most important foliar diseases of sugar beet. Due to the problems associated with traditional methods in the identification of Cercospora species, in the present study two sets of previously designed Cercospora beticola-specific primers based on calmodulin and actin genes were used for the molecular identification of C. beticola isolates. For this purpose, two standard isolates of C. beticola together with the other isolates recovered from sugar beet plants with leaf spot disease symptoms in present study were subjected to PCR amplification. Efficacy of primer sets were tested on the Cercospora isolates recovered from weed plants with leaf spot symptoms, in present study. Our results showed that the primer set based on actin gene amplified a 959 bp PCR product from the all of the isolates tested in this study. This primer set failed to distinguish C. beticola from the other Cercospora spp. isolated from weeds as well as other fungal groups. The results of multiplex PCR assay using primer sets based on calmodulin gene yielded 234 bp PCR product from all of the Cercospora spp. tested in this study and only a 176 bp PCR product from C. beticola isolates; such that successfully discriminated C. beticola from the other Cercospora isolates. The calmodulin genes primer sets can be used for the screening of Cercospora beticola from the other Cercospora spp. and for the detection and the determination of the host range of Cercospora beticola as well.