Expression pattern analysis of selected invertase and invertase inhibitor genes in Plasmodiophora brassicae‐infected (i) and control (c) roots using promoter::GUS fusions and X‐Gluc staining of whole roots (GUS, β‐glucuronidase; X‐Gluc, 5‐bromo‐4‐chloro‐3‐indoyl‐β‐d‐glucuronide). The bar indicates 1 cm. The first symptoms became macroscopically visible at 12–14 days after inoculation (dai); therefore, in the left‐hand panels, 13‐dai plants are shown, which equals the first time point of the microarray experiment (for more details, see text). In the right‐hand panels, 23‐dai plants are shown. The expression pattern is shown for promoter::GUS lines of vacuolar invertases pAtßfruct3::GUS (A, B) and pAtßfruct4::GUS (C, D), the cell wall invertase pAtcwINV1::GUS (E, F) and the invertase inhibitor pAtC/VIF1::GUS (G, H).