MpaFp confers resistance towards MPA. A) Replacing native IMPDH-A coding gene (AN10476, A. nidulans imdA) with mpaF by homologous recombination. The gene targeting substrate contains four parts: mpaF (IMPDH from MPA gene cluster), argB (selection marker) and finally TSI and TSII (targeting sequence I, 2197 bp; and II, 2244 bp flanking AN10476 (A. nidulans IMPDH)). B) Spot assay to determine sensitivity towards MPA. Ten-fold serial dilutions of spores from the two strains NID191 (reference strain with native A. nidulans imdA) and NID495 (A. nidulans imdA replaced with mpaF) were spotted on minimal medium plates with 0, 5, 25, 100 and 200 μg MPA/ml. Each row is composed of spots containing plated spores ranging from ~106 (to the left) to ~10 (to the right) as indicated in the figure.