POLYMERASE CHAIN-REACTION ASSAYS FOR THE DETECTION OF STAGONOSPORA-NODORUM AND SEPTORIA-TRITICI IN WHEAT

Polymerase chain reaction (PCR) primers have been developed that can d istinguish important wheat pathogenic fungal species and detect their DNA in infected wheat leaf tissues. Septoria tritici (teleomorph Mycos phaerella graminicola) and Stagonospora nodorum = Septoria nodorum (te leomorph Phaeosphaeria nodorum), are agronomically significant pathoge ns of wheat, causing wheat leaf and glume blotch, respectively. Primer s made to conserved sequences of the ribosomal DNA were used to PCR am plify and clone the internal transcribed spacer (ITS) regions from S. nodorum and S. tritici. The ITS regions were sequenced, the sequences were aligned, and species-specific PCR primers were designed to the po lymorphic regions. These ITS-derived primers were used to amplify spec ific fragments from the fungi from which they were designed, thus allo wing the detection of the pathogens. The primers also successfully amp lified similar-sized fragments from wheat tissues infected with the re spective fungi.