title: The transcriptional landscape of basidiosporogenesis in mature Pisolithus microcarpus basidiocarp.
abstract: Pisolithus microcarpus (Cooke & Massee) G. Cunn is a gasteromycete that produces closed basidiocarps in symbiosis with eucalypts and acacias. The fungus produces a complex basidiocarp composed of peridioles at different developmental stages and an upper layer of basidiospores free of the hyphae and ready for wind dispersal upon the rupture of the basidiocarp pellis. During basidiosporogenesis, a process that takes place inside the basidiocarp peridioles, a conspicuous reserve of fatty acids is present throughout development. While several previous studies have described basidiosporogenesis inside peridioles, very little is known about gene expression changes that may occur during this part of the fungal life cycle. The objective of this work was to analyze gene transcription during peridiole and basidiospore development, while focusing specifically on cell cycle progression and lipid metabolism.
  
  
  
  Throughout different developmental stages of the peridioles we analyzed, 737 genes were regulated between adjacent compartments (>5 fold, FDR-corrected p-value < 0.05) corresponding to 3.49% of the genes present in the P. microcarpus genome. We identified three clusters among the regulated genes which showed differential expression between the peridiole developmental stages and the basidiospores. During peridiole development, transcripts for proteins involved in cellular processes, signaling, and information storage were detected, notably those for coding transcription factors, DNA polymerase subunits, DNA repair proteins, and genes involved in chromatin structure. For both internal embedded basidiospores (hereto referred to as "Internal spores", IS) and external free basidiospores (hereto referred to as "Free spores", FS), upregulated transcripts were found to involve primary metabolism, particularly fatty acid metabolism (FA). High expression of transcripts related to β-oxidation and the glyoxylate shunt indicated that fatty acids served as a major carbon source for basidiosporogenesis.
  
  
  
  Our results show that basidiocarp formation in P. microcarpus involves a complex array of genes that are regulated throughout peridiole development. We identified waves of transcripts with coordinated regulation and identified transcription factors which may play a role in this regulation. This is the first work to describe gene expression patterns during basidiocarp formation in an ectomycorrhizal gasteromycete fungus and sheds light on genes that may play important roles in the developmental process.
authors.affiliation: Department of Microbiology/BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, Brazil.|INRA, UMR 1136 INRA-University of Lorraine, Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRA-Nancy, 54280, Champenoux, France.
authors.forename: Maíra
authors.initials: M
authors.lastname: de Freitas Pereira
authors.affiliation: IF Sudeste MG, Rio Pomba, MG, Brazil.
authors.forename: André
authors.initials: A
authors.lastname: Narvaes da Rocha Campos
authors.affiliation: Department of Microbiology/BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
authors.forename: Thalita Cardoso
authors.initials: TC
authors.lastname: Anastacio
authors.affiliation: INRA, UMR 1136 INRA-University of Lorraine, Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRA-Nancy, 54280, Champenoux, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Morin
authors.affiliation: Department of Phytopathology/BIOAGRO, Federal University of Viçosa, Viçosa, MG, Brazil.
authors.forename: Sérgio Hermínio
authors.initials: SH
authors.lastname: Brommonschenkel
authors.affiliation: INRA, UMR 1136 INRA-University of Lorraine, Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRA-Nancy, 54280, Champenoux, France.
authors.forename: Francis
authors.initials: F
authors.lastname: Martin
authors.affiliation: INRA, UMR 1136 INRA-University of Lorraine, Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRA-Nancy, 54280, Champenoux, France. annegret.kohler@inra.fr.
authors.forename: Annegret
authors.initials: A
authors.lastname: Kohler
authors.affiliation: Department of Microbiology/BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
authors.forename: Maurício Dutra
authors.initials: MD
authors.lastname: Costa
mesh_terms: D001487:Basidiomycota / Q000235:genetics*; D002453:Cell Cycle / Q000235:genetics; D016000:Cluster Analysis; D019295:Computational Biology / Q000379:methods; D048690:Fruiting Bodies, Fungal / Q000235:genetics*; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D058977:Molecular Sequence Annotation; D015203:Reproducibility of Results; D059467:Transcriptome
keywords: Cell cycle; Fatty acid metabolism; Gene expression; Peridiole development; Spores