The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

Research output: Contribution to journalLetter


Mycorrhizal symbioses -- the union of roots and soil fungi -- are universal in terrestrial ecosystems and
may have been fundamental to land colonization by plants1,2. Boreal, temperate, and montane forests all
depend upon ectomycorrhizae1. Identification of the primary factors that regulate symbiotic
development and metabolic activity will therefore open the door to understanding the role of
ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this
symbiosis to be explored. Here, we report the genome sequence of the ectomycorrhizal basidiomycete
Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This
65-million-base genome assembly contains ~ 20,000 predicted protein-encoding genes and a very large
number of transposons and repeated sequences. We detected unexpected genomic features most notably
a battery of effector-type small secreted proteins (SSP) with unknown function, several of which are only
expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae
colonizing the host root. The ectomycorrhizae-specific proteins likely play a decisive role in the
establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks
carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to
degrade non-plant cell walls, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal
fungus which enables it to grow within both soil and living plant roots. The predicted gene inventory of
the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in
biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to
develop a deeper understanding of the processes by which symbionts interact with plants within their
ecosystem in order to perform vital functions in the carbon and nitrogen cycles that are fundamental to
sustainable plant productivity.


  • Francis Martin
  • Andrea Aerts
  • Annick Brun
  • Frédéric Duchaussoy
  • Julien Gibon
  • Annegret Kohler
  • Erika Lindquist
  • Veronica Pereda
  • Asaf Salamov
  • Harris Shapiro
  • Jan Wuyts
  • Damien Blaudez
  • Marc Buée
  • Peter Brokstein
  • David Cohen
  • Pierre Emmanuel Courty
  • Pedro Coutinho
  • Etienne Danchin
  • Christine Delaruelle
  • John Detter
  • Aurélie Deveau
  • S DiFazio
  • Sebastien Duplessis
  • Laurence Fraissinet-Tachet
  • Eva Lucic
  • Pascal Frey-Klett
  • Claire Fourrey
  • Ivo Feussner
  • Gilles Gay
  • Jane Grimwood
  • Patrik Hoegger
  • P Jain
  • Sreedhar Kilaru
  • Jessy Labbé
  • Yao Chen Lin
  • Valérie Legué
  • Francois Le Tacon
  • Roland Marmeisse
  • Delphine Melayah
  • Barbara Montanini
  • Mike Muratet
  • Uwe Nehls
  • Hélène Niculita-Hirzel
  • Marie-Pierre Oudot-Le Secq
  • Martina Peter
  • Hadi Quesneville
  • Balaji Rajashekar
  • Marlis Reich
  • Nicolas Rouhier
  • Jeremy Schmutz
  • Tongming Yin
  • Michelle Chalot
  • Bernhard Henrissat
  • Ursel Kües
  • Susan Lucas
  • Yves Van de Peer
  • Gopi Podila
  • Andrea Polle
  • Patricia Pukkila
  • Paul Richardson
  • Pierre Rouzé
  • Ian Sanders
  • Jason Stajich
  • Gerald Tuskan
  • Igor Grigoriev
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biological Sciences
Original languageEnglish
Pages (from-to)88-U7
Issue number7183
Publication statusPublished - 2008
Publication categoryResearch