We isolated 12 groups of genomic clones that containedSLG-homologous regions from a genomic library constructed from anS9homozygote of self-incompatibleBrassica campestris. BothSLG9andSRK9genomic clones, which are located within the self-incompatibility (S) locus, were included in these groups. The promoter regions ofSLG9andSRK9were completely identical for at least 200 bp upstream from their respective initiation codons (ATG). The five sequence elements (boxes I to V) that are conserved in the promoters ofSLGandSRKgenes were also found in theSLG9andSRK9clones. However, one conserved element (box III) unexpectedly lacked 7 of 11 bp, although box III has been considered necessary for expression in pistil. The other ten groups of genomic clones were classified into sixSRK-like groups and fourSLG-like groups. These results indicate thatSLG,SRK,SLG-like, andSRK-like genes form a largeS-multigene family inB. campestris.
展开▼
