title: The homeobox BcHOX8 gene in Botrytis cinerea regulates vegetative growth and morphology.
abstract: Filamentous growth and the capacity at producing conidia are two critical aspects of most fungal life cycles, including that of many plant or animal pathogens. Here, we report on the identification of a homeobox transcription factor encoding gene that plays a role in these two particular aspects of the development of the phytopathogenic fungus Botrytis cinerea. Deletion of the BcHOX8 gene in both the B. cinerea B05-10 and T4 strains causes similar phenotypes, among which a curved, arabesque-like, hyphal growth on hydrophobic surfaces; the mutants were hence named Arabesque. Expression of the BcHOX8 gene is higher in conidia and infection cushions than in developing appressorium or mycelium. In the Arabesque mutants, colony growth rate is reduced and abnormal infection cushions are produced. Asexual reproduction is also affected with abnormal conidiophore being formed, strongly reduced conidia production and dramatic changes in conidial morphology. Finally, the mutation affects the fungus ability to efficiently colonize different host plants. Analysis of the B. cinerea genome shows that BcHOX8 is one member of a nine putative homeobox genes family. Available gene expression data suggest that these genes are functional and sequence comparisons indicate that two of them would be specific to B. cinerea and its close relative Sclerotinia sclerotiorum.
authors.affiliation: Unité Mixte de Recherche 5240 - Microbiologie, Adaptation et Pathogénie; Université Lyon 1, CNRS, Bayer CropScience, Villeurbanne, France.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Antal
authors.forename: Christine
authors.initials: C
authors.lastname: Rascle
authors.forename: Agnès
authors.initials: A
authors.lastname: Cimerman
authors.forename: Muriel
authors.initials: M
authors.lastname: Viaud
authors.forename: Geneviève
authors.initials: G
authors.lastname: Billon-Grand
authors.forename: Mathias
authors.initials: M
authors.lastname: Choquer
authors.forename: Christophe
authors.initials: C
authors.lastname: Bruel
mesh_terms: D020171:Botrytis / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D020224:Expressed Sequence Tags; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005801:Genes, Homeobox; D016681:Genome, Fungal; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology*; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D014774:Virulence
chemical_list: D017931:DNA Primers; D018398:Homeodomain Proteins; D014157:Transcription Factors