title: The F-actin capping protein is required for hyphal growth and full virulence but is dispensable for septum formation in Botrytis cinerea.
abstract: Filamentous (F-) actin is an integral part of the cytoskeleton allowing for cell growth, intracellular motility, and cytokinesis of eukaryotic cells. Its assembly from G-actin monomers and its disassembly are tightly regulated processes involving a number of actin-binding proteins (ABPs) such as F-actin nucleators and cross-linking proteins. F-actin capping protein (CP) is an alpha/beta heterodimer known from yeast and higher eukaryotes to bind to the fast growing ends of the actin filaments stabilizing them. In this study, we identified the orthologs of the two CP subunits, named BcCPA1 and BcCPB1, in the plant pathogenic fungus Botrytis cinerea and showed that the two proteins physically interact in a yeast two-hybrid approach. GFP-BcCPA1 fusion proteins were functional and localized to the assumed sites of F-actin accumulation, i.e. to the hyphal tips and the sites of actin ring formation. Deletion of bccpa1 had a profound effect on hyphal growth, morphogenesis, and virulence indicating the importance of F-actin capping for an intact actin cytoskeleton. As polarized growth - unlike septum formation - is impaired in the mutants, it can be concluded that the organization and/or localization of actin patches and cables are disturbed rather than the functionality of the actin rings.
authors.affiliation: Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Instituto Universitario de Investigación Vitivinícola y Agroalimentaria (IVAGRO), Universidad de Cádiz, Polígono Río San Pedro, 11510 Puerto Real, Spain. Electronic address: victoriaeugenia.gonzalez@uca.es.
authors.forename: Victoria E
authors.initials: VE
authors.lastname: González-Rodríguez
authors.affiliation: Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Instituto Universitario de Investigación Vitivinícola y Agroalimentaria (IVAGRO), Universidad de Cádiz, Polígono Río San Pedro, 11510 Puerto Real, Spain. Electronic address: carlos.garrido@gm.uca.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Garrido
authors.affiliation: Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Instituto Universitario de Investigación Vitivinícola y Agroalimentaria (IVAGRO), Universidad de Cádiz, Polígono Río San Pedro, 11510 Puerto Real, Spain. Electronic address: jesusmanuel.cantoral@uca.es.
authors.forename: Jesús M
authors.initials: JM
authors.lastname: Cantoral
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143 Münster, Germany. Electronic address: Julia.schumacher@uni-muenster.de.
authors.forename: Julia
authors.initials: J
authors.lastname: Schumacher
mesh_terms: D051344:Actin Capping Proteins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D020171:Botrytis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D025301:Hyphae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D008969:Molecular Sequence Data; D027805:Phaseolus / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D016415:Sequence Alignment; D014774:Virulence
chemical_list: D051344:Actin Capping Proteins; D005656:Fungal Proteins
keywords: Actin cytoskeleton; Cell polarity; Conidial germination; Infection; Morphogenesis