Detection of Gaeumannomyces graminis varieties using polymerase chain reaction with variety-specific primers.

ABSTRACT The polymerase chain reaction (PCR) was used for detection of Gaeumannomyces graminis, the causal agent of take-all disease in wheat, oats, and turfgrass. NS5 and NS6 universal primers amplified the middle region of 18S ribosomal DNA of Gaeumannomyces species and varieties. Primers GGT-RP (5′ TGCAATGGCTTCGTGAA 3′) and GGA-RP (5′ TTTGTGTGTGAC CATAC 3′) were developed by sequence analysis of cloned NS5-NS6 fragments. The primer pair NS5:GGT-RP amplified a single 410-bp fragment from isolates of G. graminis var. tritici, a single 300-bp fragment from isolates of G. graminis var. avenae, and no amplification products from isolates of G. graminis var. graminis or other species of Gaeumannomyces. The primer pair NS5:GGA-RP amplified a single 400-bp fragment from isolates of varieties tritici and avenae. Two sets of primer pairs (NS5:GGT-RP and NS5:GGA-RP) were used in PCR reactions to detect and identify the varieties tritici and avenae either colonizing wheat, oats, or grass roots, or in culture. No a...