Peroxisomal ABC transporters and β-oxidation during the life cycle of the filamentous fungus Podospora anserina

ATP-binding cassette transporters are ubiquitous proteins that facilitate transport of diverse substances across a membrane. However, their exact role remains poorly understood. In order to test their function in a fungus life cycle, we deleted the two Podospora anserina peroxisomal ABC transporter pABC1 and pABC2 genes as well as the three genes involved in peroxisomal ( fox2) and mitochondrial ( scdA and echA) β-oxidation. Analysis of the single and double mutants shows that fatty acid β-oxidation occurs in both organelles. Furthermore, the peroxisomal and mitochondrial fatty acid β-oxidation pathways are both dispensable for vegetative and sexual development. They are, however, differently required for ascospore pigmentation and germination, this latter defect being restored in a ΔpABC1 and ΔpABC2 background . We report also that lack of peroxisomal ABC transporters does not prevent peroxisomal long-chain fatty acid oxidation, suggesting the existence of another pathway for their import into peroxisomes. Finally, we show that some aspects of fatty acid degradation are clearly fungus species specific.