title: Genomic and transcriptomic analysis of Laccaria bicolor CAZome reveals insights into polysaccharides remodelling during symbiosis establishment.
abstract: Ectomycorrhizal fungi, living in soil forests, are required microorganisms to sustain tree growth and productivity. The establishment of mutualistic interaction with roots to form ectomycorrhiza (ECM) is not well known at the molecular level. In particular, how fungal and plant cell walls are rearranged to establish a fully functional ectomycorrhiza is poorly understood. Nevertheless, it is likely that Carbohydrate Active enZymes (CAZyme) produced by the fungus participate in this process. Genome-wide transcriptome profiling during ECM development was used to examine how the CAZome of Laccaria bicolor is regulated during symbiosis establishment. CAZymes active on fungal cell wall were upregulated during ECM development in particular after 4weeks of contact when the hyphae are surrounding the root cells and start to colonize the apoplast. We demonstrated that one expansin-like protein, whose expression is specific to symbiotic tissues, localizes within fungal cell wall. Whereas L. bicolor genome contained a constricted repertoire of CAZymes active on cellulose and hemicellulose, these CAZymes were expressed during the first steps of root cells colonization. L. bicolor retained the ability to use homogalacturonan, a pectin-derived substrate, as carbon source. CAZymes likely involved in pectin hydrolysis were mainly expressed at the stage of a fully mature ECM. All together, our data suggest an active remodelling of fungal cell wall with a possible involvement of expansin during ECM development. By contrast, a soft remodelling of the plant cell wall likely occurs through the loosening of the cellulose microfibrils by AA9 or GH12 CAZymes and middle lamella smooth remodelling through pectin (homogalacturonan) hydrolysis likely by GH28, GH12 CAZymes.
authors.affiliation: INRA, Interactions Arbres - Microorganismes, UMR1136, F-54280 Champenoux, France; Université de Lorraine, Interactions Arbres - Microorganismes, UMR1136, F-54500 Vandoeuvre-lès-Nancy, France. Electronic address: claire.fourrey@univ-lorraine.fr.
authors.forename: Claire
authors.initials: C
authors.lastname: Veneault-Fourrey
authors.affiliation: INRA, Interactions Arbres - Microorganismes, UMR1136, F-54280 Champenoux, France; Université de Lorraine, Interactions Arbres - Microorganismes, UMR1136, F-54500 Vandoeuvre-lès-Nancy, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Commun
authors.affiliation: INRA, Interactions Arbres - Microorganismes, UMR1136, F-54280 Champenoux, France; Université de Lorraine, Interactions Arbres - Microorganismes, UMR1136, F-54500 Vandoeuvre-lès-Nancy, France.
authors.forename: Annegret
authors.initials: A
authors.lastname: Kohler
authors.affiliation: INRA, Interactions Arbres - Microorganismes, UMR1136, F-54280 Champenoux, France; Université de Lorraine, Interactions Arbres - Microorganismes, UMR1136, F-54500 Vandoeuvre-lès-Nancy, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Morin
authors.affiliation: Istituto per la Protezione delle Piante del CNR, UOS Torino c/o Dipartimento di Scienze della Vita e Biologia dei Sistemi, Viale Mattioli, 25, 10125 Torino, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Balestrini
authors.affiliation: INRA, Interactions Arbres - Microorganismes, UMR1136, F-54280 Champenoux, France; Université de Lorraine, Interactions Arbres - Microorganismes, UMR1136, F-54500 Vandoeuvre-lès-Nancy, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Plett
authors.affiliation: INRA, UMR 1355, Institut Sophia Agrobiotech, F-06903 Sophia-Antipolis, France; Université de Nice Sophia-Antipolis, Institut Sophia Agrobiotech, F-06903 Sophia-Antipolis, France; CNRS, UMR 7254, Institut Sophia Agrobiotech, F-06903 Sophia-Antipolis, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Danchin
authors.affiliation: Aix-Marseille Université, AFMB, 163 Avenue de Luminy, 13288 Marseille, France.
authors.forename: Pedro
authors.initials: P
authors.lastname: Coutinho
authors.affiliation: CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
authors.forename: Ad
authors.initials: A
authors.lastname: Wiebenga
authors.affiliation: CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
authors.forename: Ronald P
authors.initials: RP
authors.lastname: de Vries
authors.affiliation: Centre National de la Recherche Scientifique, CNRS UMR 7257, 13288 Marseille, France; Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Bernard
authors.initials: B
authors.lastname: Henrissat
authors.affiliation: INRA, Interactions Arbres - Microorganismes, UMR1136, F-54280 Champenoux, France; Université de Lorraine, Interactions Arbres - Microorganismes, UMR1136, F-54500 Vandoeuvre-lès-Nancy, France.
authors.forename: Francis
authors.initials: F
authors.lastname: Martin
mesh_terms: D015870:Gene Expression; D020869:Gene Expression Profiling; D023281:Genomics; D006026:Glycoside Hydrolases / Q000096:biosynthesis* / Q000235:genetics; D055399:Laccaria / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D018517:Plant Roots / Q000382:microbiology; D032107:Populus / Q000382:microbiology; D013559:Symbiosis
chemical_list: D006026:Glycoside Hydrolases
keywords: Carbohydrate Active enZymes; Ectomycorrhiza; Symbiosis; Transcriptome profiling