[Cloning a gene related to resistance to TuMV in cabbage]

A cDNA library was constructed from cabbage 84075 which resists TuMV. The degenerate primers was designed with the disease resistance gene conservative domain (NBS-LRR). The fragments of 513 bp were amplified by RT-PCR and genomic DNA PCR from resistant material 84075, then cloned and sequenced. Two recombinants which are highly homologous with the resistance genes cloned in other plants were used as probes, (named as Bor1, Bor2), the cDNA library was screened. A positive clone was obtained, named as TuR2, whose length was 762 bp, which encodes 226 amino acids, contains a long 681 bp open reading frame (ORF), and has different homology score of amino acid compared with the cloned resistance disease genes of other plants. TuR2 was used as probe. Southern blotting hybridization with genomic DNA shows that TuR2 is probably present in single copy; No. rthern blotting hybridization with RNA shows that the gene expression is constitutive and not differential in every part of the resistance plant 84075, the result of separating detection in F2 population shows that TuR2 gene is probably related to resistance to TuMV in cabbage.