FIG. 4.

Effect of thioredoxin deletions during sexual reproduction. (Top row) Fertility defect of the ΔPaTrx1 ΔPaTrx3 and ΔPaTrx1 ΔPaTrx2 ΔPaTrx3 strains. mat+/mat− heterokaryotic mycelia of the indicated genotypes were incubated at 27°C for 1 week, at which time the perithecia are fully mature and starting to eject ascospores in wild-type strains. Incubation times of more than 3 weeks did not permit further maturation of perithecia in the ΔPaTrx1 ΔPaTrx3 and ΔPaTrx1 ΔPaTrx2 ΔPaTrx3 mutants. (Middle row) The fertility defect of the indicated mat+/mat− heterokaryons was not corrected when Δmat nuclei were added in the heterokaryons. (Bottom row) The perithecial envelope of the thioredoxin mutants/193 heterokaryon derived mostly or exclusively from the 193 parent, showing that expression of PaTrx1 or PaTrx3 was required in the perithecial envelope.