FIG. 2.

NOX-1 is essential for protoperithecia but not for ascogonium development. (A) Conidia from wild-type (WT) strains 74-OR23-1A or 74-OR8-1a and Δnox-1 strains H10.1 (mat a) or H10.17 (mat A) were inoculated on crossing medium and grown for 6 days to be used as female partners, which were fertilized with wild-type or Δnox-1 strains from the opposite mating type. Pictures were taken 13 days after fertilization. The round black structures correspond to mature perithecia. (B) The same strains were grown under identical conditions for 10 days, and protoperithecium (arrowheads) development was observed under a stereoscopic microscope. (C) Development of ascogonia (arrows) and protoperithecia (arrowheads) was induced according to the method of Bistis (5). Briefly, conidia from strains 74-OR23-1A and H10.1 were inoculated onto water-agar medium, and after 4 days, four pieces of solid crossing medium were placed close to growing mycelia and incubation was continued for 24 h. NBT staining was carried out by flooding the plates with a water solution of 2.5 mM NBT for 30 min. Pictures were taken under a stereoscopic microscope.