| Wheat is one of the main sources of human's foodstuff. Powdery mildew disease of wheat is one of the major diseases affecting wheat production. In order to understand the mechanisms underlying powdery mildew resistance of wheat, it's necessary to isolate genes associated with the resistance reactions.A near-isogenic line (NILs) (Yuma/8* Cc) of Pm4a and its recurrent parent Chancellor (Cc) were used in this study. RT-PCR was conducted using six pairs of degenerate oligonucleotide primers designed according to the conserved sequences of plant disease resistance genes that have been cloned. Five fragments, including W2, W4, W6, W8 and W490 in the size of 1121bp, 833 bp, 613 bp, 406 bp and 450 bp, respectively, were obtained, whichshowed polymorphism between the NILs. W490 derived from cDNA of seedings infected by Blumeria graminis (DC.). The sequence of W8 has over96% similarity to the barley H+-ATPase gene Hal. The amino acid sequence deduced from W2 is homologous to the O-linked GlcNAc transferase (OGT) of Arabidopsis. W4 and W6 derived from single primer amplification, and had no homology to the known sequences. The amino acid sequence deduced from W490 is highly homologous to serine/threonine kinase-like proteins.Based on the W8 sequence, a 3330 bp fragment including the whole coding region was obtained through RACE-PCR. It encodes a polypeptide of 951 amino acids, homologous to H+-ATPase. This gene was designated as Thai. In addition, two partial cDNAs of the OGT gene with an intact 3' end were obtained using a cDNA-IPCR method.Southern blot showed that W2 and W490 exist in single or oligo copies in the wheat genome. W2 was mapped to chromosome 4A using a set of C.S. nulli-tetrasomics. RNA dot blot showed that W2 might participate in the resistance reaction to powdery mildew disease of wheat.
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