title: Targeted changes of the cell wall proteome influence Candida albicans ability to form single- and multi-strain biofilms.
abstract: Biofilm formation is an important virulence trait of the pathogenic yeast Candida albicans. We have combined gene overexpression, strain barcoding and microarray profiling to screen a library of 531 C. albicans conditional overexpression strains (∼10% of the genome) for genes affecting biofilm development in mixed-population experiments. The overexpression of 16 genes increased strain occupancy within a multi-strain biofilm, whereas overexpression of 4 genes decreased it. The set of 16 genes was significantly enriched for those encoding predicted glycosylphosphatidylinositol (GPI)-modified proteins, namely Ihd1/Pga36, Phr2, Pga15, Pga19, Pga22, Pga32, Pga37, Pga42 and Pga59; eight of which have been classified as pathogen-specific. Validation experiments using either individually- or competitively-grown overexpression strains revealed that the contribution of these genes to biofilm formation was variable and stage-specific. Deeper functional analysis of PGA59 and PGA22 at a single-cell resolution using atomic force microscopy showed that overexpression of either gene increased C. albicans ability to adhere to an abiotic substrate. However, unlike PGA59, PGA22 overexpression led to cell cluster formation that resulted in increased sensitivity to shear forces and decreased ability to form a single-strain biofilm. Within the multi-strain environment provided by the PGA22-non overexpressing cells, PGA22-overexpressing cells were protected from shear forces and fitter for biofilm development. Ultrastructural analysis, genome-wide transcript profiling and phenotypic analyses in a heterologous context suggested that PGA22 affects cell adherence through alteration of cell wall structure and/or function. Taken together, our findings reveal that several novel predicted GPI-modified proteins contribute to the cooperative behaviour between biofilm cells and are important participants during C. albicans biofilm formation. Moreover, they illustrate the power of using signature tagging in conjunction with gene overexpression for the identification of novel genes involved in processes pertaining to C. albicans virulence.
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France; Univ. Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris, France.
authors.forename: Vitor
authors.initials: V
authors.lastname: Cabral
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France.
authors.forename: Sadri
authors.initials: S
authors.lastname: Znaidi
authors.affiliation: School of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Louise A
authors.initials: LA
authors.lastname: Walker
authors.affiliation: INSA, UPS, INP, ISAE, LAAS, Université de Toulouse, Toulouse, France; UMR792 Ingénierie des Systèmes Biologiques et des Procédés, INRA, Toulouse, France; UMR5504, CNRS, Toulouse, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Martin-Yken
authors.affiliation: INSA, UPS, INP, ISAE, LAAS, Université de Toulouse, Toulouse, France; LAAS, CNRS, Toulouse, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Dague
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Legrand
authors.affiliation: School of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Keunsook
authors.initials: K
authors.lastname: Lee
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France.
authors.forename: Murielle
authors.initials: M
authors.lastname: Chauvel
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Firon
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France.
authors.forename: Tristan
authors.initials: T
authors.lastname: Rossignol
authors.affiliation: INRA, UMR1319 Micalis, Jouy-en-Josas, France; AgroParisTech, UMR Micalis, Thiverval Grignon, France.
authors.forename: Mathias L
authors.initials: ML
authors.lastname: Richard
authors.affiliation: School of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Munro
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Bachellier-Bassi
authors.affiliation: Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France; INRA, USC2019, Paris, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: d'Enfert
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D002176:Candida albicans / Q000166:cytology / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology; D002473:Cell Wall / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D010641:Phenotype; D020543:Proteome / Q000235:genetics / Q000502:physiology*; D033081:Shear Strength / Q000502:physiology; D059467:Transcriptome / Q000502:physiology
chemical_list: D005656:Fungal Proteins; D020543:Proteome