This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ramamoorthy, V.
Right arrow Articles by Shah, D. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ramamoorthy, V.
Right arrow Articles by Shah, D. M.

 Previous Article  |  Next Article 

Eukaryotic Cell, February 2009, p. 217-229, Vol. 8, No. 2
1535-9778/09/$08.00+0     doi:10.1128/EC.00255-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Sphingolipid C-9 Methyltransferases Are Important for Growth and Virulence but Not for Sensitivity to Antifungal Plant Defensins in Fusarium graminearum{triangledown} ,{dagger}

Vellaisamy Ramamoorthy, Edgar B. Cahoon, Mercy Thokala, Jagdeep Kaur, Jia Li, and Dilip M. Shah*

Donald Danforth Plant Science Center, 975 North Warson Road, Saint Louis, Missouri 63132

Received 29 July 2008/ Accepted 14 November 2008

The C-9-methylated glucosylceramides (GlcCers) are sphingolipids unique to fungi. They play important roles in fungal growth and pathogenesis, and they act as receptors for some antifungal plant defensins. We have identified two genes, FgMT1 and FgMT2, that each encode a putative sphingolipid C-9 methyltransferase (C-9-MT) in the fungal pathogen Fusarium graminearum and complement a Pichia pastoris C-9-MT-null mutant. The {Delta}Fgmt1 mutant produced C-9-methylated GlcCer like the wild-type strain, PH-1, whereas the {Delta}Fgmt2 mutant produced 65 to 75% nonmethylated and 25 to 35% methylated GlcCer. No {Delta}Fgmt1{Delta}Fgmt2 double-knockout mutant producing only nonmethylated GlcCer could be recovered, suggesting that perhaps C-9-MTs are essential in this pathogen. This is in contrast to the nonessential nature of this enzyme in the unicellular fungus P. pastoris. The {Delta}Fgmt2 mutant exhibited severe growth defects and produced abnormal conidia, while the {Delta}Fgmt1 mutant grew like the wild-type strain, PH-1, under the conditions tested. The {Delta}Fgmt2 mutant also exhibited drastically reduced disease symptoms in wheat and much-delayed disease symptoms in Arabidopsis thaliana. Surprisingly, the {Delta}Fgmt2 mutant was less virulent on different host plants tested than the previously characterized {Delta}Fggcs1 mutant, which lacks GlcCer synthase activity and produces no GlcCer at all. Moreover, the {Delta}Fgmt1 and {Delta}Fgmt2 mutants, as well as the P. pastoris strain in which the C-9-MT gene was deleted, retained sensitivity to the antifungal plant defensins MsDef1 and RsAFP2, indicating that the C-9 methyl group is not a critical structural feature of the GlcCer receptor required for the antifungal action of plant defensins.

* Corresponding author. Mailing address: Donald Danforth Plant Science Center, 975 North Warson Road, St Louis, MO 63132. Phone: (314) 587-1481. Fax: (314) 587-1581. E-mail: dshah{at}danforthcenter.org

{triangledown} Published ahead of print on 21 November 2008.

{dagger} Supplemental material for this article may be found at http://ec.asm.org/.

Eukaryotic Cell, February 2009, p. 217-229, Vol. 8, No. 2
1535-9778/09/$08.00+0     doi:10.1128/EC.00255-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»