title: Analysis of a Blumeria graminis-secreted lipase reveals the importance of host epicuticular wax components for fungal adhesion and development.
abstract: The biotrophic powdery mildew fungus Blumeria graminis releases extracellular materials to the surface of fungal infection structures that facilitate anchoring them to hydrophobic plant surfaces prior to infection; however, the chemistry of fungal adhesives and the mechanism of adhesion remain largely unclear. Expressed sequence tag analysis led to identification of a secreted lipase, Lip1, from B. graminis. Expression of LIP1 is dramatically upregulated during the early stages of fungal development. Lip1, secreted to the surface of fungal cell walls, possesses lipolytic activity against a broad range of glycerides and releases alkanes and primary fatty alcohols from the epicuticular wax of wheat leaves. Of the epicuticular wax components released by Lip1 activity, long-chain alkanes are the most efficient cues for triggering appressorium formation. Pretreatment of wheat leaves with Lip1, thereby removing leaf surface wax, severely compromises components of fungal pathogenicity, including conidial adhesion, appressorium formation, and secondary hypha growth. Our data suggest that Lip1 activity releases cues from the host surface to promote pathogen development and infection.
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, Canada.
authors.forename: Jie
authors.initials: J
authors.lastname: Feng
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Guosheng
authors.initials: G
authors.lastname: Liu
authors.forename: David
authors.initials: D
authors.lastname: Greenshields
authors.forename: Wenyun
authors.initials: W
authors.lastname: Shen
authors.forename: Susan
authors.initials: S
authors.lastname: Kaminskyj
authors.forename: Geoff R
authors.initials: GR
authors.lastname: Hughes
authors.forename: Youliang
authors.initials: Y
authors.lastname: Peng
authors.forename: Gopalan
authors.initials: G
authors.lastname: Selvaraj
authors.forename: Jitao
authors.initials: J
authors.lastname: Zou
authors.forename: Yangdou
authors.initials: Y
authors.lastname: Wei
mesh_terms: D001203:Ascomycota / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D008049:Lipase / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D019441:Plant Epidermis; D018515:Plant Leaves / Q000382:microbiology; D013172:Spores, Fungal; D013379:Substrate Specificity; D014908:Triticum / Q000382:microbiology; D014885:Waxes
chemical_list: D014885:Waxes; D008049:Lipase