[Cloning and characterization of pathogenesis-related protein 1 from wheat-H. villosa translocation lines]

A Triticum aestivum-Haynaldia villosa 6VS/6AL translocation line contained powdery mildew resistance gene Pm21 which is effective against all the current biotypes of Erygsiphe gramins. Cloning of the related genes for powdery mildew resistance is significance for understanding its resistance mechanism and disease resistance breeding. Using RT-PCR and RACE technology, a wheat pathogenesis related protein 1 cDNA clone (TaPr-1) corresponding to a mRNA differentially induced in resistant 6VS/6AL translocation line compared to susceptible wheat cultivar "Yangmai 5" by powdery mildew infection was isolated and characterized. This sequence contained 823 bp and had an open reading frame (ORF) containing 164 amino acids with 24 amino acids in the putative signal peptide and 140 amino acids comprising the mature peptide (15.1 kD). The deduced amino acid sequence showed close homology to PR-1 like proteins, which have been isolated from many plants. Northern blot analysis revealed the most abundantly accumulation of the corresponding mRNA 12 h after infection in translocation line (6VS/6AL). The obviously difference in the expression of the PRw-1 was also observed between resistant translocation line (6VS/6AL) and susceptible parent "Yangmai 5", it showed the TaPr-1 gene is related to powdery mildew resistance. Southern blot indicated that the wheat genome contains more than one copies of TaPr-1 genes, and there are polymorphism between translocation lines and "Yanmai 5", the result shows that 6VS may contain TaPr-1 genes.