While pathogenic fungi are responsible for numerous deaths and billions of dollars in crop damage each year, fungi used in the bioprocessing industry are used to produce billions of dollars in beneficial products. In nearly all relevant environments, fungi are likely to experience some degree of starvation, where survival requires recycling internal components in a process called autophagy.  Yet, in spite of it's likely importance, relatively little information is available on autophagy, or its related effects, in filamentous fungi.  We have systematically deleted a number of putative autophagy genes from the model fungus Aspergillus nidulans, and are using a sophisticated set of experimental tools to assess subsequent phenotypes providing insight regarding gene function.  Surprisingly, autophagy appears to be involved in regulation of a diverse set of, seemingly, unrelated cellular processes. For example, proteomic analysis shows that deletion of a putative autophagy gene (Anatg13) leads to altered expression of a number of proteins related to chronological life span (CLS). Shake flask experiments on this strain show that low levels of autophagy (induced through addition of rapamycin) lead to increased CLS, but this phenotype is abolished in Anatg13 deletion strains. Autophagy also appears to impact fungal cell walls, and fungal morphology. For example, Anatg13 deletion mutants show a significant reduction in both growth and branching rates in complete minimal medium, implying autophagy may be active even in the absence of starvation. In addition, the Anatg13 deletion appears to impact morphology as these mutants show no significant change in branching rate in any of the various growth environments employed. This implies autophagy, or the AnAtg13 protein, may play a role in regulation of fungal branching. We will discuss these findings and their potential application in the bioprocess industry.

Systems biology of fungal autophagy

243rd National Meeting (2012)

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