UP-PCR cross blot hybridization as a tool for identification of anastomosis groups in the Rhizoctonia solani complex

A universally primed (UP)-PCR cross hybridization assay was developed for r apid identification of isolates or Rhizoctonia solani into the correct anas tomosis group (AG). Twenty-one AG tester isolates belonging to 11 AGs of R. solani were amplified with a single UP primer which generated multiple PCR fragments for each isolate. The amplified products were spotted onto a fil ter, immobilized and used for cross hybridization against amplification pro ducts From the different isolates. Isolates within AG subgroups cross hybri dize strongly, whereas between different AGs little or no cross hybridizati on occurs. Sixteen Rhizoclonia isolates from diseased sugar beets and potat oes were identified using the assay. The results were supported by restrict ion fragment length polymorphism analysis of the ITS1-5.8S-ITS2 region of t he nuclear encoded ribosomal DNA. Through standardization and use of quick non-radioactive labeling techniques, the UP-PCR cross hybridization assay h as potential for routine use by modern DNA chip technology. (C) 2001 Federa tion of European Microbiological Societies. Published by Elsevier Science B .V. All rights reserved.