Gene structure and protein domain prediction of the three candidate genes, ZmWAK-RLK2, ZmWAK-RLK1, and ZmWAK-RLP1, from the resistant Htn1 locus. Predicted domains are in color. Exons are represented as rectangular bars, and introns as black lines between the exons. GUB (GUB_WAK), wall-associated receptor kinase galacturonan-binding; Ser/Thr-kinase, catalytic domain of the serine/threonine kinases and interleukin 1 receptor-associated kinases; SP, signal peptide; TM, transmembrane domain; WAK (WAK_assoc), wall-associated receptor kinase C-terminal. Dark blue, RD-kinase; bright blue, non-RD kinase.