A Network of HMG-box Transcription Factors Regulates Sexual Cycle in the Fungus Podospora anserina
Figure 3
Microscopic phenotypes of Δkef1 (ΔPahmg9) strain.
(A) Appressorium-like structures in the Δkef1 strain and in the wild type (WT). Development of appressorium-like structures was not affected in the Δkef1 strain. The pictures were taken every 1 µm as Z stacks, with “0” corresponding to hyphae growing onto the cellophane layer (see panel C). Arrowheads indicate needle-like hyphae that penetrated the cellophane layer; p: palm-like structures within the cellophane layer. (B) Comparison of hyphal fusion (anastomosis) in wild-type (WT) and Δkef1 strains. In the wild type, anastomoses were never observed in apical hyphae (1), while they were occasionally observed in the subapical area (2). In Δkef1 strain, anastomoses were profuse in apical (1) and in subapical (2) areas. Most notably, anastomosis occurred between the apex of hyphae at the leading edge and neighbouring apical hyphae (see arrows in Δkef1 in 1). (C) Schematic of appressorium-like development in P. anserina. a: appressorium-like structure including the palm-like structure and the needle-like hyphae; c: cellophane layer on which mycelium is growing. (D) Spermatia and their spermatogonia were present in the subapical area of the Δkef1 strain but were absent from the same area in the wild-type strain. Scale bar = 10 µm in all panels.