title: Diversity in yeast-mycelium dimorphism response of the Dutch elm disease pathogens: the inoculum size effect.
abstract: Dutch elm disease (DED) is caused by the dimorphic fungi Ophiostoma ulmi, Ophiostoma novo-ulmi, and Ophiostoma himal-ulmi. A cell population density-dependent phenomenon related to quorum sensing was previously shown to affect the reversible transition from yeast-like to mycelial growth in liquid shake cultures of O. novo-ulmi NRRL 6404. Since the response to external stimuli often varies among DED fungal strains, we evaluated the effect of inoculum size on 8 strains of the 3 species of DED agents by determining the proportion of yeast and mycelium produced at different spore inoculum concentrations in defined liquid shake medium. The results show that not all DED fungi strains respond similarly to inoculum size effect, since variations were observed among strains. It is thus possible that the different strains belonging to phylogenetically close species use different signalling molecules or molecular signalling pathways to regulate their growth mode via quorum-sensing mechanisms.
authors.affiliation: Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.|Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.
authors.forename: Marie-Ève
authors.initials: MÈ
authors.lastname: Wedge
authors.affiliation: Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.|Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.
authors.forename: Erika Sayuri
authors.initials: ES
authors.lastname: Naruzawa
authors.affiliation: Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.|Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.
authors.forename: Martha
authors.initials: M
authors.lastname: Nigg
authors.affiliation: Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.|Centre d'Étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Pavillon Charles-Eugène-Marchand, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada.
authors.forename: Louis
authors.initials: L
authors.lastname: Bernier
mesh_terms: D015169:Colony Count, Microbial; D025282:Mycelium; D055156:Ophiostoma / Q000254:growth & development / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D053038:Quorum Sensing; D013172:Spores, Fungal; D034403:Ulmus / Q000382:microbiology*
keywords: Ophiostoma spp; density-dependent phenomenon; détection du quorum; levure; mycelium; mycélium; phénomène dépendant de la densité; quorum sensing; yeast