Four BEL1 -type homeobox genes in common wheat. (A) Schematic representation of structures of four putative WBLH proteins. Probe positions used in Southern blot analyses are underlined. Numbers indicate the amino acid positions of individual domains. (B) A phylogenetic tree based on the homeodomain sequences of BLH proteins. In addition to WBLH1 to WBLH4, six rice BLH, eight Arabidopsis BLH and barley JUBEL1 and JUBEL2 proteins were included. Homeodomain sequences of WKNOX1, which is a member of the wheat class 1 KNOX protein family, and Caenorhabditis elegans CEH-20, which is a homolog of PBX protein, were used as outgroups. The phylogenetic tree was constructed according to the UPGMA method.