Primers based on specific rDNA-ITS sequences for PCR detection of Rhizoctonia solani, R-solani AG 2 subgroups and ecological types, and binucleate Rhizoctonia

We have designed primers for identification of the economically important p lant pathogenic Rhizoctonia solani, for AG 2 and for each subgroup and an e cological type of AG 2. These specific primers have been designed based on specific sequences of the ITS regions in the R. solani species complex. The PCR procedure involves amplification of the 5.8S ribosomal DNA and part of the ITS regions, using the designed primers in combination with the genera l fungal primers ITS1F and ITS4B. Two of the primers amplify under optimal PCR conditions R. solani AG 1, AG 2, AG 3, AG 4, AG 5 and binucleate Rhizoc tonia (BNR), and six more primers amplify specifically R. solani AG 2, the subgroups, AG 2-1, AG 2-2 and AG 2-3, and the ecological type AG 2-t. In th is study DNAs from R. solani AG 2 and AG 4 growing on infected radish were amplified similarly to DNAs from axenic cultures. PCR detection has time sa ving advantages over traditional isolation methods for detection of Rhizoct onia on infected plant tissue and provides a powerful tool of identificatio n.