Multigene family for Bowman-Birk type proteinase inhibitors of wild soja and soybean: the presence of two BBI-A genes and pseudogenes

Genes for Bowman-Birk type protease inhibitors (BBIs) of wild soja (Glycine soja) and soybean (Glycine max) comprise a multigene family. The organization of the genes for wild soja BBIs (wBBIs) was elucidated by an analysis of their cDNAs and the corresponding genomic sequences, and compared with the counterparts in the soybean. The cDNAs encoding three types of wild soja BBIs (wBBI-A, -C, and -D) were cloned. Two subtypes of cDNAs for wBBI-A, designated wBBI-Al and -A2, were further identified. Similar subtypes (sBBI-AI and -A2) were also found in the soybean genome. cDNA sequences for wBBIs were highly homologous to those for the respective soybean homologs. Phylogenetic analysis of these cDNAs demonstrated the evolutional proximity between these two leguminae strains.