Control of glucosylceramide production and morphogenesis by the Bar1 ceramide synthase in Fusarium graminearum.

William R Rittenour,Edgar B Cahoon,Steven D Harris,Ming Chen,Jae-Hyuk Yu

doi:10.1371/journal.pone.0019385

William R Rittenour, Edgar B Cahoon + Show 3 more

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https://doi.org/10.1371/journal.pone.0019385

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Journal: PloS one	Publication Date: Apr 29, 2011
Citations: 71	License type: CC BY 4.0

Affiliation: University of Nebraska–Lincoln

Abstract

The contribution of plasma membrane proteins to the virulence of plant pathogenic fungi is poorly understood. Accordingly, the objective of this study was to characterize the acyl-CoA dependent ceramide synthase Bar1 (previously implicated in plasma membrane organization) in the wheat pathogen Fusarium graminearum. The role of Bar1 in mediating cell membrane organization was confirmed as ΔBAR1 mutants failed to display a distinct sterol-rich domain at the hyphal tip. The ΔBAR1 mutants were non-pathogenic when inoculated onto wheat heads, and their in vitro growth also was severely perturbed. ΔBAR1 mutants were incapable of producing perithecia (sexual fruiting structures) and only produced macroconidia (asexual spores) in the presence of NaCl. Sphingolipid analyses indicated that Bar1 is specifically necessary for the production of glucosylceramides in both F. graminearum and Aspergillus nidulans. Interestingly, glucosylceramides appear to mediate sensitivity to heat stable antifungal factor (HSAF), as, in addition to ΔBAR1 mutants, a glucosylceramide synthase deficient mutant of Yarrowia lipolytica is also resistant to HSAF.

Highlights

Fusarium graminearum is the causative agent of head blight on small grains such as wheat
Several proteins have been isolated from detergentresistant membrane (DRM) domains in Saccharomyces cerevisiae, Candida albicans, and Cryptococcus neoformans
We have previously described the existence of two distinct clades of acyl-CoA-dependent ceramide synthases in filamentous fungi [15]

Summary

Introduction

Fusarium graminearum (teleomorph Gibberella zeae) is the causative agent of head blight (scab) on small grains such as wheat. The ATPase Pma has become a marker for DRM fractions in both S. cerevisiae and C. albicans [8,9] Given their involvement in clustering membrane proteins and signaling complexes on the cell surface, lipid rafts represent attractive targets for the discovery of novel virulence factors in plant pathogenic fungi (such as those that might regulate MAP kinase and other signaling pathways; [12]). Consistent with this notion, GPI-anchored virulence determinants Sod (Cu/Zn superoxide dismutase) and Plb (lysophospholipase) localize to DRM fractions of the human pathogen C. neoformans [13]

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