Cloning, mapping and protein expression of wheat thaumatin protein gene (TaTLP1)

To understand wheat powdery mildew resistance mechanism, reverse-transcription polymerase chain reaction (RT-PCR) and cDNA library screening were performed to isolate the full-length cDNA of wheat thaumatin protein gene from wheat-Haynaldia villosa 6VS/6AL translocation line. The putative amino acid sequence of this gene consists of 173 amino acid residues, and is an acid polypeptide. It was highly homologous to thaumatin proteins isolated from other plants, so it is designated as TaTLP1 (GenBank accession number: AF384146). Northern blot analysis of TaTLP1 showed that the transcription difference obviously existed between resistant wheat-Haynaldia villosa 6VS/6AL translocation line and susceptible "Yangmai 5". The result of western blot showed that the protein expression product of TaTLP1 gene in wheat seedling leaf was a soluble cytoplasm protein, whose expression was induced by fungus Erysiph graminis and apparently related to disease resistance of the 6VS/6AL translocation line. Southern blot indicated that the TaTLP1 gene had 1-2 copies in wheat genome, and had been localized on the specific region of 7B and 7D chromosomes in wheat.