Influence of AreA and AreB on secondary metabolite cluster gene expression.

The F. fujikuroi Wt and the ΔAREA and ΔAREB deletion mutants were cultivated for 3 (A, B, C) or 7 (D) days in ICI liquid cultures with 6 mM glutamine (6) or 60 mM glutamine (60) as sole nitrogen source. (A) Differentially regulated secondary metabolite gene clusters, represented by PKS-, NRPS-, TC- and DMATS-encoding genes. Data are based on microarray analysis. (B) Northern blot analysis of secondary metabolite cluster gene expression: CPS/KS (copalyl diphosphate/kaurene-synthase, GA-cluster), BIK2 (monooxygenase, BIK-cluster), APF6 (o-methyltransferase, APF-cluster), FUB5 (homoserine o-acyltransferase, FUB-cluster). (C) Variation in pigmentation of the strains in ICI liquid culture. (D) Variation in bikaverin production. Culture supernatant was analyzed by HPLC-DAD. The peaks of bikaverin and norbikaverin were integrated at wavelength of 510 nm and depicted in relation to the total cell dry mass of the cultures.