Serial analysis of gene expression: stage-specificity of putative secretome members of the Melampsora unisequence dataset. Similarities in serial analysis of gene expression (SAGE) patterns of 182 putative secretome members of the Melampsora unisequence dataset were determined using an average linkage hierarchical clustering according to the Spearman Rank Correlation. Corresponding tags were identified as described in the Methods section. Each row represents a tag, whereas each column corresponds to a SAGE library. 22H_C: 22 hours after inoculation (compatible interaction); 22H_I: 22 hours after inoculation (incompatible interaction); 2H: 2 hours after inoculation (germinating spores); 5D_C: 5 days after inoculation (compatible interaction); and 5D_I: 5 days after inoculation (incompatible interaction). Genes upregulated during the biotrophic or pre-biotrophic stages are highlighted in blue and yellow, respectively. Medium blue = genes specific to the biotrophic stage; Light blue = genes upregulated during the biotrophic stage; Dark yellow = genes upregulated in 22H_I; Medium yellow = genes upregulated in 22H_C; and Light yellow = genes upregulated in 2 H. The relative abundance of the SAGE tag in the library correlates with the intensity of the red color (black, not present; intense red, highly abundant). Brackets indicate clades containing homologues of haustorially expressed secreted proteins (HESPs) 735, 417, and 379, respectively.