An Assay Based on the Polymerase Chain Reaction for the Detection of N‐ and L‐types of Pseudocercosporella herpotrichoides in Wheat

Abstract A polymerase chain reaction (PCR) test combined with restriction enzyme digestion of an amplified ribosomal DNA fragment is currently available for the identification of N‐ and L‐type isolates of Pseudocercosporella herpotrichoides from purified fungal DNA. This study shows that both types of the fungus can be differentiated in the plant using the PCR assay and that the test is extremely sensitive. The PCR assay is used to compare the development of one isolate of each the N‐ and L‐type in wheat under glasshouse conditions. The results indicate that for an identical infection date, the N‐type tends to penetrate the tissues faster than the L‐type.