Cloning and expression analysis of a NBS-LRR resistance gene homology cDNA sequence from wheat

Reverse transcription-polymerase chain reaction(RT-PCR) and rapid amplification of cDNA ends(RACE) were applied in cloning disease resistance-associated gene with ESTs(Contig 914) as target sequence came from incompatible interaction cDNA library of TcLr19 to obtain wheat leaf rust resistance-associated gene.The full length cDNA of the aimed gene is 3 042 bp and containing an open reading frame of 2 739 bp.The sequence analysis showed that the gene belonged to the CC-NBS-LRR type gene, temporarily designated as TaNLR.TaNLR has continuous poly A tail and a typical poly adenylation signal.The ProtParam program putatively predicted that this gene encoded a protein of 912amino acids.The phylogenetic tree analysis showed 89%identity of the protein encoded by TaNLR with that of Hordeum vulgare. Real-time PCR analysis revealed that TaNLRgene was induced and down-regulated expression during interaction between P.triticina and TcLr19.The resistance homology sequence was successfully obtained in TcLr19, which laid the foundation for understanding the function of NBS-LRR to wheat leaf rust resistance.