title: Protist-type lysozymes of the nematode Caenorhabditis elegans contribute to resistance against pathogenic Bacillus thuringiensis.
abstract: Pathogens represent a universal threat to other living organisms. Most organisms express antimicrobial proteins and peptides, such as lysozymes, as a protection against these challenges. The nematode Caenorhabditis elegans harbours 15 phylogenetically diverse lysozyme genes, belonging to two distinct types, the protist- or Entamoeba-type (lys genes) and the invertebrate-type (ilys genes) lysozymes. In the present study we characterized the role of several protist-type lysozyme genes in defence against a nematocidal strain of the Gram-positive bacterium Bacillus thuringiensis. Based on microarray and subsequent qRT-PCR gene expression analysis, we identified protist-type lysozyme genes as one of the differentially transcribed gene classes after infection. A functional genetic analysis was performed for three of these genes, each belonging to a distinct evolutionary lineage within the protist-type lysozymes (lys-2, lys-5, and lys-7). Their knock-out led to decreased pathogen resistance in all three cases, while an increase in resistance was observed when two out of three tested genes were overexpressed in transgenic lines (lys-5, lys-7, but not lys-2). We conclude that the lysozyme genes lys-5, lys-7, and possibly lys-2 contribute to resistance against B. thuringiensis, thus highlighting the particular role of lysozymes in the nematode's defence against pathogens.
authors.affiliation: Institute for Evolution and Biodiversity, University of Muenster, Muenster, Germany. claudia_boehnisch@web.de
authors.forename: Claudia
authors.initials: C
authors.lastname: Boehnisch
authors.forename: Daniel
authors.initials: D
authors.lastname: Wong
authors.forename: Michael
authors.initials: M
authors.lastname: Habig
authors.forename: Kerstin
authors.initials: K
authors.lastname: Isermann
authors.forename: Nicolaas K
authors.initials: NK
authors.lastname: Michiels
authors.forename: Thomas
authors.initials: T
authors.lastname: Roeder
authors.forename: Robin C
authors.initials: RC
authors.lastname: May
authors.forename: Hinrich
authors.initials: H
authors.lastname: Schulenburg
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000472:pathogenicity*; D017173:Caenorhabditis elegans / Q000378:metabolism* / Q000382:microbiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D009113:Muramidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D009113:Muramidase