Tubers with decreased apyrase under the control of the tuber-specific B33 promoter show specific changes in their transcript profiles compared with the wild type. RNA was extracted from growing tubers of separate plants from the wild type and lines B33:10 and B33:25 and converted into dye-labeled second-strand cDNA. The second-strand DNA was hybridized together with complementary labeled wild-type second-strand cDNA on the TIGR 10k potato array, giving four hybridized arrays in total. Within the two replicate arrays for one of the two lines, a dye swap was performed. Data are shown as a snapshot of the metabolic overview slide of MapMan (Thimm et al., 2004) using a recently developed mapping file (Rotter et al., 2007). Changes in transcript levels coding for extensins and related cell wall proteins (A), genes involved in starch synthesis (B), and glycosyltransferases (C) are highlighted.