Cloning, characterization and chromosome localization of two powdery mildew resistance-related gene sequences from wheat

Reverse-transcription Polymerase Chain Reaction (RT-PCR) was performed using cDNAs as templates from wheat-Haynaldia villosa 6VS/6AL translocation line and "Yangmai 5" induced with fungus Erysiphe graminis, and degenerate primers designed based on the conserved amino acid sequences of known plant disease-resistance genes. The cDNA sequences encoding cyclophilin-like and H+-ATPase-like genes were first isolated and characterized in wheat. The putative amino acid sequences of the two clones showed that they were highly homologous to those of cyclophilin proteins and H+ -ATPases isolated from other plants. Thus they were designated as Ta-Cyp and Talpha-MAH. The obvious expression differences could be observed between wheat-H. villosa 6VS/6AL translocation line and susceptible wheat cultivar "Yangmai 5", implying that the two genes may be related with the resistance of wheat-H. villosa 6VS/6AL translocation line to disease. Southern blot indicated that the wheat genome contained 2 - 3 copies of Ta-Cyp gene and one copy of the Talpha-MAH gene. Chinese Spring nulli-tetrasomic line analysis located the Ta-Cyp homologous genes on wheat chromosome 6A, 6B and 6D. Southem blot using Ta-Cyp clone as a probe showed that are polymorphic bands existed among the H. villosa, amphiploid of Triticum durum-H. villosa, wheat-H. villosa 6VS/6AL translocation line and "Yangmai 5", suggesting that Ta-Cyp homologies exist in wheat genome as well as on the short arm of chromosome 6V in H. villosa.