In fungi, where non-fermentable compounds like fatty acids and acetate can serve as sole source of carbon and energy, the acetylCoA must be converted to C4 compounds via the Dichlorphenamide glyoxylate cycle, allowing gluconeogenesis. Peroxisome plays an essential role in this process, as it could serve as the location where fatty acid beta-oxidation occurs to generate acetyl-CoA, meanwhile many glyoxylate cycle enzymes are also peroxisomal. In M. oryzae, Colletotrichum lagenarium, and Fusarium graminearum, mutants with aberrant peroxisome function showed severe defects in utilization of lipids, fatty acids, and acetate. Yeast Dsnf1 is devoid of peroxisomal structures and fails to survive on media with non-fermentable carbon sources. However, we found DMosnf1 possessed abnormal other than abolished peroxisomes with enlarged size in the mycelia. The poor growth of DMosnf1 on fatty acids or NaAC-contained media suggested an aberrant function of the enlarged peroxisomes therein. In S. cerevisiae, PEX1/PEX11, FOX2, and ICL1, all of which are regulated by Snf1, play an important role in peroxisomal biosynthesis and proliferation, peroxisomal fatty acid beta-oxidation, and the glyoxylate cycle, respectively. Insufficient amount of peroxisomes could give rise to serious consequence in M. oryzae. It is known that enormous turgor pressure is required for the pathogen to physically penetrate the host surface, and its genesis relies on the substantial glycerol accumulation via rapid lipolysis during appressorial maturation. In order to maintain the efficient lipid mobilization, fatty acids resulting from lipolysis demand to be transported to peroxisomes where they are metabolized via b-oxidation to form acetyl-CoA. The resulting L-Ascorbyl 6-palmitate acetyl-CoA is not only the precursor in melanin synthesis but also supplies substrates to synthesize chitin and glucans via the glyoxylate shunt and gluconeogenesis. So peroxisome, the major b-oxidation location and acetyl-CoA sink, plays a central role in appressorial morphogenesis and function. Mutants with dysfunctional peroxisomes display significant defects in lipid metabolism, melanin layer formation, appressorial wall porosity, turgor generation, and ultimately pathogenicity.