The aerial mycelia of the PDC1 deletion mutant adhered too tightly to the media, however, and we instead used the back of the surgical blade. Mycelia formed just above and below the agar surface were much denser in PDC1 deletion mutant. Although perithecia maturation in the PDC1 deletion mutant was

variable and dependant on induction conditions, PDC1 deletion mutants produced many immature perithecia compared with the wild-type and complemented strains (Fig. 1a). Mature perithecia of wild-type and complemented strains contained viable ascospores and discharged them normally, but most of the immature perithecia of the PDC1 deletion mutants were barren (Fig. 1b). The PDC2 and PDC3 deletion mutants displayed wild-type-like vegetative growth, conidiation, sexual learn more reproduction, virulence, and toxin production (Table S3 and Fig. S3). Perithecia maturation is defective in ACS1 deletion mutants because of reduced lipid production (Lee et al., 2011). Thus, we analyzed lipid

production in PDC1 mutants and found that total lipid production in the PDC1 deletion mutant was not significantly different compared with the wild-type and complemented strains. We also observed that POL production was unaffected in the PDC1 deletion mutant Antiinfection Compound Library (Fig. S4). Cell surface hydrophobicity tests demonstrated that aerial mycelia of PDC1 deletion mutants were highly wettable by water (Fig. 2). Lipid bodies were not observed to accumulate in aerial mycelia of PDC1 deletion mutants, although wild-type and complemented strains were observed to contain a large amount of lipids in their hyphae. Mycelia of PDC1 deletion mutants embedded in agar, however, possessed more lipid bodies than the embedded mycelia of wild-type and complemented strains. The lipid content of the mycelia in the PDC1 deletion mutants did not change when potassium acetate was added to the agar media (Fig. 2). We examined the expression of PDC1-GFP and ACS1-GFP in both aerial and embedded mycelia and found that PDC1-GFP was highly expressed in both of types of mycelia (Fig. 3). ACS1-GFP, however, was highly expressed Farnesyltransferase only in aerial mycelia (Fig. 4). Deletion of the PDC1 gene results in suppression of ACS1-GFP expression

(Fig. 4). When acetate was added to induce ACS1 expression, ACS1-GFP was not detected in the mycelia of the PDC1 deletion mutant (Fig. 4). As previously reported, the ACS1 deletion mutant exhibited defective perithecia development (Lee et al., 2011). However, it was observed that all of the ACS1 mutant phenotypes, including POL production, are masked in the ∆pdc1 ∆acs1 double mutant (Fig. 5). Thus, the PDC1 gene is epistatic to the ACS1 gene. Five-day-old carrot agar incubations were sliced into 2-mm-wide sections and evaluated by dissection and optical microscopy. Embedded mycelia of the wild-type and complemented strains penetrated into the agar to depths of more than 8 mm, whereas embedded mycelia of the PDC1 deletion mutant penetrated to depths of only 1 mm (Fig. 6).