title: Diversity and evolution of ABC proteins in mycorrhiza-forming fungi.
abstract: BACKGROUND
  Transporter proteins are predicted to have an important role in the mycorrhizal symbiosis, due to the fact that this type of an interaction between plants and fungi requires a continuous nutrient and signalling exchange. ABC transporters are one of the large groups of transporter proteins found both in plants and in fungi. The crucial role of plant ABC transporters in the formation of the mycorrhizal symbiosis has been demonstrated recently. Some of the fungal ABC transporter-encoding genes are also induced during the mycorrhiza formation. However, no experimental evidences of the direct involvement of fungal ABC transporters in this process are available so far. To facilitate the identification of fungal ABC proteins with a potential role in the establishment of the mycorrhizal symbiosis, we have performed an inventory of the ABC protein-encoding genes in the genomes of 25 species of mycorrhiza-forming fungi.
  
  
  RESULTS
  We have identified, manually annotated and curated more than 1300 gene models of putative ABC protein-encoding genes. Out of those, more than 1000 models are predicted to encode functional proteins, whereas about 300 models represent gene fragments or putative pseudogenes. We have also performed the phylogenetic analysis of the identified sequences. The sets of ABC proteins in the mycorrhiza-forming species were compared to the related saprotrophic or plant-pathogenic fungal species. Our results demonstrate the high diversity of ABC genes in the genomes of mycorrhiza-forming fungi. Via comparison of transcriptomics data from different species, we have identified candidate groups of ABC transporters that might have a role in the process of the mycorrhiza formation.
  
  
  CONCLUSIONS
  Results of our inventory will facilitate the identification of fungal transporters with a role in the mycorrhiza formation. We also provide the first data on ABC protein-coding genes for the phylum Glomeromycota and for orders Pezizales, Atheliales, Cantharellales and Sebacinales, contributing to the better knowledge of the diversity of this protein family within the fungal kingdom.
authors.affiliation: Department of Forest Sciences, University of Helsinki, P.O. Box 27, FIN-00014, Helsinki, Finland. Andriy.Kovalchuk@helsinki.fi.
authors.forename: Andriy
authors.initials: A
authors.lastname: Kovalchuk
authors.affiliation: UMR 1136, INRA/Université de Lorraine, Interactions Arbres/Microorganismes, INRA, Institut National de la Recherche Agronomique, Centre INRA de Nancy, 54280, Champenoux, France. kohler@nancy.inra.fr.
authors.forename: Annegret
authors.initials: A
authors.lastname: Kohler
authors.affiliation: UMR 1136, INRA/Université de Lorraine, Interactions Arbres/Microorganismes, INRA, Institut National de la Recherche Agronomique, Centre INRA de Nancy, 54280, Champenoux, France. fmartin@nancy.inra.fr.
authors.forename: Francis
authors.initials: F
authors.lastname: Martin
authors.affiliation: Department of Forest Sciences, University of Helsinki, P.O. Box 27, FIN-00014, Helsinki, Finland. Fred.Asiegbu@helsinki.fi.
authors.forename: Fred O
authors.initials: FO
authors.lastname: Asiegbu
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005658:Fungi / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D014644:Genetic Variation; D016013:Likelihood Functions; D005810:Multigene Family; D038821:Mycorrhizae / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D064210:Secondary Metabolism / Q000235:genetics
chemical_list: D018528:ATP-Binding Cassette Transporters; D005656:Fungal Proteins