Fusarium verticillioides peroxins associated with peroxisomal docking/translocation module serve important roles in fumonisin biosynthesis and virulence

Peroxisomes are ubiquitous organelles in eukaryotic cells that fulfill a variety of important metabolic functions. In this study, we investigated the role of Docking/Translocation Module (DTM) peroxins, mainly FvPex8, FvPex13, FvPex14, and FvPex33, in virulence and fumonisin B1 (FB1) biosynthesis. Protein interaction experiments suggested that FvPex13 serves as the core subunit of DTM. When we generated gene deletion mutants (ΔFvpex8, ΔFvpex13, ΔFvpex14, ΔFvpex33, ΔFvpex33/14) and examined whether the expression of other peroxin genes were affected in the DTM mutants, ΔFvpex8 strain showed most drastic changes to gene expression profiles. When we tested other physiological changes in these mutants, we observed disparity in carbon source utilization, especially sucrose and butyrate, as well as unsaturated fatty acids oleic acid and linoleic acid. Deletion mutants exhibited defect in cell wall integrity when stress agents were applied. The mutants also showed higher levels of lipid droplet accumulation when compared to WT, particularly under nutrient starvation. Notably, ΔFvpex8 mutant showed significant FB1 reduction and altered expression of (polyketide synthase) and (ABC transporter) genes. However, FvPex13 was primarily responsible for virulence when tested on maize stalks, while ΔFvpex33/14 double mutant also showed virulence defect. In summary, our study suggests that FvPex13 is the core component of DTM, regulating peroxisome membrane biogenesis as well as PTS1- and PTS2-mediated transmembrane cargo transportation. However, FvPex8 is predicted to serve as a key component in DTM that affects peroxisome function in β-oxidation and FB1 biosynthesis in .