Fig.3-7 Morphology of C100, ΔMareA and OE-MareA in mycelium from different nitrogen sources
3.2.5 Morphological analysis of mycelium and spores under scanning electron microscope
In PDA medium, the mycelium of C100 exhibited a lamellar shape, while the spores showed folds. The ΔMareA mycelium and spore surface were smooth. The OE-MareA mycelium collapsed severely, and the spores had depressions in the middle. Under PDA-Gln culture conditions, both C100 and ΔMareA mycelia were columnar with an uneven spore surface. On the other hand, OE-MareA showed a lamellar shape with a flatter and smoother spore surface. When grown on PDA-(NH4)2SO4 medium, both C100 mycelium and spores had full and smooth surfaces. However, ΔMareA and OE-MareA spores were collapsed to varying degrees. Under PDA-NaNO3 medium condition, C100 mycelium was cylindrical with a non-smooth surface. ΔMareA mycelium was flaky and twisted, while OE-MareA mycelium was very smooth. Additionally, the volume of C100 and ΔMareA spores was smaller than that of OE-MareA . In PDA-Urea medium, the mycelium of C100 was smooth but slightly depressed, ΔMareA mycelium and spores were smooth and full with relatively small volumes, whereas OE-MareA displayed a rough lamellar surface for its myelum along with fuller-spored characteristics. Overall, the AreA gene had an effect on the growth and morphology of mycelium and spores, but had little impact on their thickness and size. The most significant difference between the three strains was observed when Gln and NaNO3 were used as nitrogen sources. As shown in Figure 3-8.