Detection of distribution of vegetative incompatibility genes (vic) of cryphonectria parasitica population in the Eastern Blacksea region

In recent years, it has been observed that the number of vegetative compatibility group of chestnut blight agent, Cryphonectria parasitica, increased significantly. The aim of this study was to determine vc groups of C. parasitica in the Eastern Black Sea Region, where vegetative compatibility group diversity was high, by using PCR with molecular markers being developed from 6 vegetative incompatibility loci. In this study, vic genotypes of 20 field and 30 single ascospore isolates were determined by using specific primers belonging to vic1, vic2, vic3, vic5, vic6 and vic7 gene regions. Among field isolates, 11 vc groups were identified as EU-2, EU-3, EU-7, EU-8, EU-12, EU-17, EU-21, EU-22, EU-30 and EU-55. Single ascospore isolates divided into 15 vc groups as EU-1, EU-2, EU-3, EU-5, EU-8, EU-11, EU-12, EU-17, EU-21, EU-22, EU-29. According to PCR genotyping each isolate was subjected to pairing in coculture testing with European vc group tester. In 15 of the field isolates and in 21 of the single ascospore isolates, there is good agreement between PCR and coculturing testing. But, in 5 field and 9 single ascospore isolates, there are disagreement between tests. These findings suggested that there is another vic genes or alleles related to vic genes in vegetative incompatibility system in C. parasitica which has been thought to be controlled by 6 vic genes with 2 alleles. Although PCR based assay is much more practical and faster than coculture test, the results of the two methods are not always consistent and it is necessary to make more studies on vic genes.