Receptor-mediated exopolysaccharide perception controls bacterial infection

Nature. 2015 Jul 16;523(7560):308-12. doi: 10.1038/nature14611. Epub 2015 Jul 8.

Abstract

Surface polysaccharides are important for bacterial interactions with multicellular organisms, and some are virulence factors in pathogens. In the legume-rhizobium symbiosis, bacterial exopolysaccharides (EPS) are essential for the development of infected root nodules. We have identified a gene in Lotus japonicus, Epr3, encoding a receptor-like kinase that controls this infection. We show that epr3 mutants are defective in perception of purified EPS, and that EPR3 binds EPS directly and distinguishes compatible and incompatible EPS in bacterial competition studies. Expression of Epr3 in epidermal cells within the susceptible root zone shows that the protein is involved in bacterial entry, while rhizobial and plant mutant studies suggest that Epr3 regulates bacterial passage through the plant's epidermal cell layer. Finally, we show that Epr3 expression is inducible and dependent on host perception of bacterial nodulation (Nod) factors. Plant-bacterial compatibility and bacterial access to legume roots is thus regulated by a two-stage mechanism involving sequential receptor-mediated recognition of Nod factor and EPS signals.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Carbohydrate Sequence
  • Lipopolysaccharides / chemistry
  • Lipopolysaccharides / metabolism*
  • Lotus / genetics
  • Lotus / metabolism*
  • Lotus / microbiology*
  • Molecular Sequence Data
  • Mutation / genetics
  • Phenotype
  • Plant Epidermis / metabolism
  • Plant Epidermis / microbiology
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plant Root Nodulation
  • Protein Kinases / chemistry
  • Protein Kinases / genetics
  • Protein Kinases / metabolism
  • Protein Structure, Tertiary
  • Receptors, Cell Surface / chemistry
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Rhizobium / metabolism*
  • Root Nodules, Plant / metabolism
  • Root Nodules, Plant / microbiology
  • Signal Transduction
  • Species Specificity
  • Suppression, Genetic / genetics
  • Symbiosis*

Substances

  • Lipopolysaccharides
  • Plant Proteins
  • Receptors, Cell Surface
  • Protein Kinases

Associated data

  • GENBANK/UNKNOWN