Figure 4.

Regulated expression of prpA is required for asexual development. (A) Aconidial phenotype caused by increased expression of prpA. Conidiophores from wild-type (A28; left) and alcA(p)∷GFP∷prpA (ACS9; right) strains were examined under a dissecting scope (top: bars, 20 μm) and light microscopy (bottom: bars, 10 μm). Note that conidiophores of the wild-type strain develop specific asexual structures such as vesicles, metulae, phialides, and conidia, whereas the alcA(p)∷GFP∷prpA strain primarily forms vacuolated aerial hyphae. (B) Relative quantification of prpA mRNA expression during asexual development as determined by real-time RT–PCR. The wild-type GR5 strain was grown in YGV liquid medium (plus uridine and uracil) at 30° for 16 hr. The mycelial mass was then transferred to YGV plates and incubated at 30°. Exposure to an air interface stimulates conidiophore production. Accordingly, samples were collected at 0, 2, 3, 4, 5, 6, and 8 hr after transfer. (C) Relative quantification of prpA mRNA expression in an alcA(p)∷abaA strain using real-time RT–PCR. The wild-type GR5 and the alcA(p)∷abaA TPM1 strains were grown in MN liquid medium (plus uridine and uracil for GR5) for 12 hr. Mycelia were subsequently transferred to MN–dextrose or MN–ethanol media for an additional 6 hr. Values represent the fold change in prpA expression compared to GR5.