MOLECULAR CLONING AND CHARACTERIZATION OF PEROXIDASE GENES FROM OAT ( AVENA SATIVA L. VAR. OGLE ) WITH PUTATIVELY INDUCED RESISTANCE TO ERYSIPHE GRAMINIS F. SP.TRITICI

ECORC, Agriculture and Agri-Food Canada, Ottawa ON K1A 0C6 Canada

Molecular Cloning and characterization of Peroxidase Genes from Oat ( Avena sativa L. var. Ogle ) with Putatively Induced Resistance to Erysiphe graminis f. sp. tritici Davis W. Cheng and Ken C. Armstrong Eastern Cereal and Oilseeds Research Center, 960 Carling Avenue, Ottawa, Ontario K1A 0C6, Canada Two peroxidase genes, temporarily designated pxc2 and pxc6, were cloned and characterized from oat ( Avena sativa L. var. Ogle ) based on a peroxidase gene sequence from common wheat ( Triticum aestivum L. ). They are 1191 bp and 1197 bp in length and contain 3 exons and 2 introns in almost the same position . The mRNA splicing site is typical of other eukaryotic genes. Their exon sequences are more conserved ( 79.4% - 88.7% ) than their intron sequences ( 42.1% - 45% ) . Blast search results indicated that the gene sequences reported here are very similar to the barley mRNA for peroxidase induced by powdery mildew ( 85% - 91% ) , the wheat pox2 gene induced by powdery mildew with haem-binding activity ( 85% - 89% ), and the wheat pathogen resistance peroxidase gene induced to powdery mildew ( 86% - 100% ). The putative proteins encoded by oat pxc2 and pxc6 genes consist of 313 aa ( pI 7.98 ) and 314 aa ( pI 8.18 ) respectively compared to the wheat peroxidase gene which consists of 310 aa ( pI 7.98 ). The alignment of amino acid sequences indicated that the structural homologies between oat peroxidase PXC2 and PXC6 and wheat and barley peroxidases are still very high (64.3% - 75.4% ). Experiments to study the developmental expression and chromosomal localization of these peroxidase genes from oat will also be outlined.