Interaction network of salt-responsive genes in Malus zumi. The interactions of salt responsive genes were predicted by their homologs in Arabidopsis. A total of 22 up-regulated genes (red), 12 down-regulated genes (green) in microarray, and 15 potentially interactive proteins (blue), were presented in the interaction network. CDPK appeared as quadrilateral, lines between CDPK and its interactive proteins were magenta; MAPK appeared in hexagon, lines between MAPK and its interactive proteins were khaki; CIPKs appeared in octagon, lines between CIPKs and its interactive proteins were red. The thick lines represented the direct interaction with kinases, the thin lines represented the interaction between proteins. Details of gene information were listed in Supplementary file (Table S2).