Classification of genes according to their specific expression patterns in five cell-types of AM roots. A: Genes expressed in ARB, CMR, and EPI were classified into seven categories. B: Genes expressed in APP and NAP were classified into three categories. While the 10 categories were defined on the basis of significant expression differences, all subcategories were differentiated based on detectable gene expression, using the MtPt4-thresholds as a reference. Grey-scaled boxes visualize different expression levels in the respective cell-types, ranging from white (no expression) to black (strong expression). Abbreviations: ARB, cortical cells containing arbuscules; CMR, cortical cells from mycorrhizal roots; EPI, epidermal cells from mycorrhized roots; APP, appressorial areas; NAP, non-appressorial areas; equ., equally; ind, induced; logFC, log2 fold-change; p, p-value. *To emphasize the importance of specific gene expression, genes were also considered as specific for a respective cell-type(s), if only one logFC ratio was above the threshold; # genes were also grouped into this subcategory if only one of the logFC ratios was significant; ∑: sum of genes in one category.