Pex16 is involved in peroxisome and Woronin body formation in the white koji fungus, Aspergillus luchuensis mut. kawachii

Abstract

We characterized Pex16 in Aspergillus luchuensis mut. kawachii to examine the role of peroxisomes on citric acid production during the shochu-fermentation process. Rice koji made using a Δpex16 strain exhibited no significant change in citric acid accumulation but a 1.4-fold increase in formic acid production. Microscopic observation of mRFP-SKL (a peroxisome protein marker) showed that pex16 disruption decreased the number of dot-like structures per hyphal cell to 5% of the control. Pex16-GFP exclusively co-localized with mRFP-SKL throughout the hyphae including the very close position to the septal pore. Moreover, the Δpex16 strain was hypersensitive to calcofluor white, which appeared to induce bursting of the hyphal tip and translocation of mRFP-SKL signals to the septal pore. These results indicate that Pex16 does not play a role in citric acid accumulation but is significantly involved in peroxisome and Woronin body formation in Aspergillus kawachii.