Amino acid sequence comparison of Lrk gene products isolated from barley (Hv1Lrk1, Hv1Lrk2, and Hv3Lrk), wheat (Lrk10 and 3ASLrk), rice (Os8Lrk), and maize (Zm2Lrk). The extracellular domains of genes related to wheat gene Lrk10 showed two groups of homology corresponding to the Triticeae-homologous chromosome groups 1 and 3.