Cloning And Sequencing Resistance Genes To The Cereal Cyst Nematode From Aegilops Variabilis

Cereal cyst nematode (CCN) is a damaging pathogen of broad acre cereal crops in Australia, Europe, North America, India and China. It affects wheat, barley, oat and triticale and causes yield loss of up to 80%. At present, Transferring resistance genes against CCN into wheat cultivars and breeding varieties are considered one of the most effective methods for controlling the CCN. However, there are very limited reports concerning the cloning studies of resistance genes against the cereal cyst nematode.According to the sequence of Rccn4 which had high similarity to the nucleotide binding site (NBS) coding region of cereal cyst nematode resistance gene, Cre3, We designed three 3'nested primers. Using single oligonucleotide nested PCR (SON-PCR) we successfully amplified one band, Rccn-L, of 1264bp from E-10 which is the wheat-Ae.variabilis translocation line containing the cereal cyst nematode resistance gene of Ae.variabilis. We found that this band of interesting is the 3'flanking sequence of 1209bp in size of Rccn4. The coding region was 1026bp, which contained an incomplete open reading frame and a terminator codon, without initiation codon and intron, encoding a peptide of 342 amino acid residues, and shared 86﹪nucleotide sequence identity with Cre3. This peptide had a conserved LRR domain, containing the imperfect repeats,XXLXXLXXL, which contains 17﹪leucine residues and shares, respectively, 89﹪nucleotide sequence and 78﹪amino acid sequence identity with the LRR sequence of Cre3 locus. This research firstly used SON-PCR in the research of plant genome successfully, which indicated that...