GAT-1 is required for D-galacturonic acid (D-GalA)-mediated induction of pectinases. (A,B) Relative expression levels of the exo-polygalacturonase gene gh28-2 (NCU06961) in N. crassa as determined by quantitative PCR. Sucrose pre-grown WT and ∆gat-1 mycelia were transferred to medium with 0.5% citrus peel pectin, 2 μM D-GalA or w/o carbon source (NoC). Samples were taken 4 h after transfer. Relative transcript quantities (RQ) are depicted, where 1 represents the transcription level on NoC. The ∆gat-1 deletion strain displayed a strong reduction of pectinase induction in both conditions. WT, wild-type.