Glucosylceramide synthase is essential for alfalfa defensin-mediated growth inhibition but not for pathogenicity of Fusarium graminearum

Vellaisamy Ramamoorthy, Edgar B. Cahoon, Jia Li, Mercy Thokala, Robert E. Minto, Dilip M. Shah

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

Antifungal defensins, MsDef1 and MtDef4, from Medicago spp., inhibit the growth of a fungal pathogen, Fusarium graminearum, at micromolar concentrations. However, molecular mechanisms by which they inhibit the growth of this fungus are not known. We have characterized a functional role of the fungal sphingolipid glucosylceramide in regulating sensitivity of the fungus to MsDef1 and MtDef4. A null mutation of the FgGCS1 gene encoding glucosylceramide synthase results in a mutant lacking glucosylceramide. The ΔFggcs1-null mutant becomes resistant to MsDef1, but not to MtDef4. It shows a significant change in the conidial morphology and displays dramatic polar growth defect, and its mycelia are resistant to cell wall degrading enzymes. Contrary to its essential role in the pathogenicity of a human fungal pathogen, Cryptococcus neoformans, GCS1 is not required for the pathogenicity of F. graminearum. The ΔFggcs1 mutant successfully colonizes wheat heads and corn silk, but its ability to spread in these tissues is significantly reduced as compared with the wild-type PH-1 strain. In contrast, it retains full virulence on tomato fruits and Arabidopsis thaliana floral and foliar tissues. Based on our findings, we conclude that glucosylceramide is essential for MsDef1-mediated growth inhibition of F. graminearum, but its role in fungal pathogenesis is host-dependent.

Original languageEnglish (US)
Pages (from-to)771-786
Number of pages16
JournalMolecular Microbiology
Volume66
Issue number3
DOIs
StatePublished - Nov 1 2007

Fingerprint

ceramide glucosyltransferase
Defensins
Medicago sativa
Fusarium
Glucosylceramides
Virulence
Growth
Fungi
Medicago
Sphingolipids
Cryptococcus neoformans
Silk
Mycelium
Lycopersicon esculentum
Arabidopsis
Cell Wall
Triticum
Zea mays
Fruit
Head

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this

Glucosylceramide synthase is essential for alfalfa defensin-mediated growth inhibition but not for pathogenicity of Fusarium graminearum. / Ramamoorthy, Vellaisamy; Cahoon, Edgar B.; Li, Jia; Thokala, Mercy; Minto, Robert E.; Shah, Dilip M.

In: Molecular Microbiology, Vol. 66, No. 3, 01.11.2007, p. 771-786.

Research output: Contribution to journalArticle

Ramamoorthy, Vellaisamy ; Cahoon, Edgar B. ; Li, Jia ; Thokala, Mercy ; Minto, Robert E. ; Shah, Dilip M. / Glucosylceramide synthase is essential for alfalfa defensin-mediated growth inhibition but not for pathogenicity of Fusarium graminearum. In: Molecular Microbiology. 2007 ; Vol. 66, No. 3. pp. 771-786.
@article{ed7b7ba6bca146fbb39f741f1940eead,
title = "Glucosylceramide synthase is essential for alfalfa defensin-mediated growth inhibition but not for pathogenicity of Fusarium graminearum",
abstract = "Antifungal defensins, MsDef1 and MtDef4, from Medicago spp., inhibit the growth of a fungal pathogen, Fusarium graminearum, at micromolar concentrations. However, molecular mechanisms by which they inhibit the growth of this fungus are not known. We have characterized a functional role of the fungal sphingolipid glucosylceramide in regulating sensitivity of the fungus to MsDef1 and MtDef4. A null mutation of the FgGCS1 gene encoding glucosylceramide synthase results in a mutant lacking glucosylceramide. The ΔFggcs1-null mutant becomes resistant to MsDef1, but not to MtDef4. It shows a significant change in the conidial morphology and displays dramatic polar growth defect, and its mycelia are resistant to cell wall degrading enzymes. Contrary to its essential role in the pathogenicity of a human fungal pathogen, Cryptococcus neoformans, GCS1 is not required for the pathogenicity of F. graminearum. The ΔFggcs1 mutant successfully colonizes wheat heads and corn silk, but its ability to spread in these tissues is significantly reduced as compared with the wild-type PH-1 strain. In contrast, it retains full virulence on tomato fruits and Arabidopsis thaliana floral and foliar tissues. Based on our findings, we conclude that glucosylceramide is essential for MsDef1-mediated growth inhibition of F. graminearum, but its role in fungal pathogenesis is host-dependent.",
author = "Vellaisamy Ramamoorthy and Cahoon, {Edgar B.} and Jia Li and Mercy Thokala and Minto, {Robert E.} and Shah, {Dilip M.}",
year = "2007",
month = "11",
day = "1",
doi = "10.1111/j.1365-2958.2007.05955.x",
language = "English (US)",
volume = "66",
pages = "771--786",
journal = "Molecular Microbiology",
issn = "0950-382X",
publisher = "Wiley-Blackwell",
number = "3",

}

TY - JOUR

T1 - Glucosylceramide synthase is essential for alfalfa defensin-mediated growth inhibition but not for pathogenicity of Fusarium graminearum

AU - Ramamoorthy, Vellaisamy

AU - Cahoon, Edgar B.

AU - Li, Jia

AU - Thokala, Mercy

AU - Minto, Robert E.

AU - Shah, Dilip M.

PY - 2007/11/1

Y1 - 2007/11/1

N2 - Antifungal defensins, MsDef1 and MtDef4, from Medicago spp., inhibit the growth of a fungal pathogen, Fusarium graminearum, at micromolar concentrations. However, molecular mechanisms by which they inhibit the growth of this fungus are not known. We have characterized a functional role of the fungal sphingolipid glucosylceramide in regulating sensitivity of the fungus to MsDef1 and MtDef4. A null mutation of the FgGCS1 gene encoding glucosylceramide synthase results in a mutant lacking glucosylceramide. The ΔFggcs1-null mutant becomes resistant to MsDef1, but not to MtDef4. It shows a significant change in the conidial morphology and displays dramatic polar growth defect, and its mycelia are resistant to cell wall degrading enzymes. Contrary to its essential role in the pathogenicity of a human fungal pathogen, Cryptococcus neoformans, GCS1 is not required for the pathogenicity of F. graminearum. The ΔFggcs1 mutant successfully colonizes wheat heads and corn silk, but its ability to spread in these tissues is significantly reduced as compared with the wild-type PH-1 strain. In contrast, it retains full virulence on tomato fruits and Arabidopsis thaliana floral and foliar tissues. Based on our findings, we conclude that glucosylceramide is essential for MsDef1-mediated growth inhibition of F. graminearum, but its role in fungal pathogenesis is host-dependent.

AB - Antifungal defensins, MsDef1 and MtDef4, from Medicago spp., inhibit the growth of a fungal pathogen, Fusarium graminearum, at micromolar concentrations. However, molecular mechanisms by which they inhibit the growth of this fungus are not known. We have characterized a functional role of the fungal sphingolipid glucosylceramide in regulating sensitivity of the fungus to MsDef1 and MtDef4. A null mutation of the FgGCS1 gene encoding glucosylceramide synthase results in a mutant lacking glucosylceramide. The ΔFggcs1-null mutant becomes resistant to MsDef1, but not to MtDef4. It shows a significant change in the conidial morphology and displays dramatic polar growth defect, and its mycelia are resistant to cell wall degrading enzymes. Contrary to its essential role in the pathogenicity of a human fungal pathogen, Cryptococcus neoformans, GCS1 is not required for the pathogenicity of F. graminearum. The ΔFggcs1 mutant successfully colonizes wheat heads and corn silk, but its ability to spread in these tissues is significantly reduced as compared with the wild-type PH-1 strain. In contrast, it retains full virulence on tomato fruits and Arabidopsis thaliana floral and foliar tissues. Based on our findings, we conclude that glucosylceramide is essential for MsDef1-mediated growth inhibition of F. graminearum, but its role in fungal pathogenesis is host-dependent.

UR - http://www.scopus.com/inward/record.url?scp=35448933741&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=35448933741&partnerID=8YFLogxK

U2 - 10.1111/j.1365-2958.2007.05955.x

DO - 10.1111/j.1365-2958.2007.05955.x

M3 - Article

C2 - 17908205

AN - SCOPUS:35448933741

VL - 66

SP - 771

EP - 786

JO - Molecular Microbiology

JF - Molecular Microbiology

SN - 0950-382X

IS - 3

ER -