Characterization of secreted proteins. (a) Number of genes found in identified protein families in the apoplastic secretome based on conserved domains and motifs using InterProScan. (b) Mean total peptide intensities for each sample across the four replicates. Error bars indicate standard deviation of the mean. (c) Venn diagrams of differentially expressed transcripts in the microarray and differentially abundant proteins in the apoplast. Only the 785 proteins with Potato Genome Sequencing Consortium (PGSC) annotations from 1075 differentially abundant proteins were used for comparison.