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  • The EMBO Journal (2007) 26, 3923 - 3935
  • doi:10.1038/sj.emboj.7601826

Published online: 9 August 2007

LysM domains mediate lipochitin–oligosaccharide recognition and Nfr genes extend the symbiotic host range

Simona Radutoiu1,a, Lene H Madsen1,a, Esben B Madsen1, Anna Jurkiewicz1, Eigo Fukai1,b, Esben MH Quistgaard1, Anita S Albrektsen1, Euan K James2, Søren Thirup1 and Jens Stougaard1

  1. Laboratory of Gene Expression, Department of Molecular Biology, University of Aarhus, Aarhus, Denmark
  2. School of Life Sciences, University of Dundee, Dundee, UK

Correspondence to:

Jens Stougaard, Laboratory of Gene Expression, Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10, 8000 Aarhus C, Denmark. Tel.: +45 89 42 50 11; Fax: +45 86 20 12 22; E-mail: stougaard@mb.au.dk

aThese authors contributed equally to this work

bPresent address: Plant Functional Genomics Laboratory, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan

Received 3 April 2007; Accepted 18 July 2007

Legume–Rhizobium symbiosis is an example of selective cell recognition controlled by host/non-host determinants. Individual bacterial strains have a distinct host range enabling nodulation of a limited set of legume species and vice versa. We show here that expression of Lotus japonicus Nfr1 and Nfr5 Nod-factor receptor genes in Medicago truncatula and L. filicaulis, extends their host range to include bacterial strains, Mesorhizobium loti or DZL, normally infecting L. japonicus. As a result, the symbiotic program is induced, nodules develop and infection threads are formed. Using L. japonicus mutants and domain swaps between L. japonicus and L. filicaulis NFR1 and NFR5, we further demonstrate that LysM domains of the NFR1 and NFR5 receptors mediate perception of the bacterial Nod-factor signal and that recognition depends on the structure of the lipochitin–oligosaccharide Nod-factor. We show that a single amino-acid variation in the LysM2 domain of NFR5 changes recognition of the Nod-factor synthesized by the DZL strain and suggests a possible binding site for bacterial lipochitin–oligosaccharide signal molecules.

  • Keywords:

    • host range,
    • lipochitin–oligosaccharides,
    • LysM,
    • receptor,
    • symbiosis