Abstract: The PCR degenerate primers were designed according to the conservative domain TIR-NBS-LRR of most disease resistant genes in plants. DNA fragments of 240 to 980 bp were amplified by genomic DNA and cDNA PCR from B. campestris ssp.chinensis resistant materials Xuekeqing and Suzhouqing. Ten resistant gene analogs were obtained which contain the TIR-NBS-LRR domain.The deduced amino acid sequences have different homology scores compared with those of resistance genes or resistance gene analogs from other plants in GeneBank. A cluster analysis based on the deduced amino acid sequences with several resistance genes from other plants, these RGAs can be classified into five major groups. Using RGA950 as probe, Southern bloting analysis showed there existed multi-copies in genomic DNA of Xuekeqing. These RGAs can further be used as probes for cloning of resistance gene and construction of genetic map in B. campestris ssp.chinensis.

Key words: B. campestris ssp.chinensis, resistance gene analog, TIR-NBS-LRR, Southern blot