Isolation and characterization of a class ISLG gene from Chinese cabbage (Brassica campestris)

In Brassica species, self-incompatibility in the recognition reaction betwe en self and non-self pollens is determined by two genes, SLG and SRK, at th e S locus. We have cloned and characterized a genomic DNA fragment containi ng a complete open reading frame of the SLG gene from Chinese cabbage. The genomic clone, named BcSLG2, was found to possess the region that shares a homology of 77% in amino acid identity with the SLG46 gene of Brassica camp estris. Northern blot analysis revealed that the BeSLG2 gene expression is restricted to the pistil of Chinese cabbage flower. In situ hybridization s howed that in the pistil, the gene is expressed predominantly in the stigma tic tissue. Much lower expression in the tapetum was also detectable at an immature stage of the flower development. Southern blot hybridization with the BcSLG2 DNA probe showed polymorphism in the SLG,gene organization of th e Chinese cabbage plants. These results will provide valuable information i n understanding the S gene complex of the Chinese cabbage plants.