Sem1 is required for the maturation of cleistothecia in <i>A</i>. <i>nidulans</i>.

<p><b>(A)</b> The <i>Δsem1</i> strain is delayed in formation of green asexual spores on minimal media in light in comparison to <i>A</i>. <i>nidulans</i> wildtype strain (<i>sem1</i>) or the complementation strain (<i>Δsem1</i>::<i>sem1-gfp</i>) with a functional Sem1-GFP. <b>(B)</b> <i>Δsem1</i> grows slower compared to <i>sem1</i> or complementation strains. Upper panel- the respective strains were point-inoculated with 10,000 spores and incubated in light for the indicated time points. Lower panel- the colony diameter was plotted. The wildtype grows 1.3±0.03 cm per day and <i>Δsem1</i> grows 0.81±0.03 cm per day. Significance of differences was calculated with t-test compared to <i>sem1</i>, **p<0.01, n = 4. <b>(C)</b> Deletion of <i>sem1</i> impairs asexual spore formation. Spores were visible in all strains only after 2 days of asexual growth. Wildtype and complementation produced ≈ 150x10⁶ spores/ml, this number remained similar over the time course. Increased conidia were measured in the deletion strain over time, with maxima of ≈ 94x10⁶ spores/ml after 5 days of asexual growth (64% compared to wildtype). For the quantification of asexual spore, plates were inoculated with 10,000 spores and harvested at the indicated time points. The values shown are the average ± SD from 2 independent experiments. Significance of differences was calculated with t-test compared to <i>sem1</i>, *p<0.05, **p<0.01. <b>(D)</b> <i>Δsem1</i> mutant strain shows delayed formation of conidiophores (red circles). All asexual growth impairments were restored in the complementation strain. <b>(E)</b> Sem1 is required for maturation of sexual fruiting bodies (cleistothecia) in darkness. <b>(F)</b> <i>Δsem1</i> mutant strain is block in early sexual development and develop only Hülle cells and primordia (p) after 10 days of sexual growth. Wildtype and complementation strains produced pigmented cleistothecia (Cl) after 7 days. Cleistothecia were squeezed to check for the presence of ascospores. Scale bars: 50 μm for full size images, 20 μm for squeezed cleistothecia and 200 μm for the panel comparing the size of the sexual structures in the respective strains. <b>(G)</b> Similar numbers of cleistothecia per cm² were observed in wildtype or complementation strains. The average size of the cleistothecia from <i>Δsem1</i> was 5850±823 μm². 15% of cleistothecia from wildtype and complementation had similar size and contained ascospores (Fig 1F, squeezed panel). Columns represent average number of cleistothecia ± SD per cm², n = 2.