Activation of members of a MAPK module in β-glucan elicitor-mediated non-host resistance of soybean

Andrea Daxberger, Andrea Nemak, Axel Mithöfer, Judith Fliegmann, Wilco Ligterink, Heribert Hirt, Jürgen Ebel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Plants recognize microbial pathogens by discriminating pathogen-associated molecular patterns from self-structures. We study the non-host disease resistance of soybean (Glycine max L.) to the oomycete, Phytophthora sojae. Soybean senses a specific molecular pattern consisting of a branched heptaglucoside that is present in the oomycetal cell walls. Recognition of this elicitor may be achieved through a β-glucan-binding protein, which forms part of a proposed receptor complex. Subsequently, soybean mounts a complex defense response, which includes the increase of the cytosolic calcium concentration, the production of reactive oxygen species, and the activation of genes responsible for the synthesis of phytoalexins. We now report the identification of two mitogen-activated protein kinases (MAPKs) and one MAPK kinase (MAPKK) that may function as signaling elements in triggering the resistance response. The use of specific antisera enabled the identification of GmMPKs 3 and 6 whose activity is enhanced within the signaling pathway leading to defense reactions. Elicitor specificity of MAPK activation as well as the sensitivity against inhibitors suggested these kinases as part of the β-glucan signal transduction pathway. An upstream GmMKK1 was identified based on sequence similarity to other plant MAPKKs and its interaction with the MAPKs was analyzed. Recombinant GmMKK1 interacted predominantly with GmMPK6, with concomitant phosphorylation of the MAPK protein. Moreover, a preferential physical interaction between GmMKK1 and GmMPK6 was demonstrated in yeast. These results suggest a role of a MAPK cascade in mediating β-glucan signal transduction in soybean, similar to other triggers that activate MAPKs during innate immune responses in plants.

Original languageEnglish (US)
Pages (from-to)1559-1571
Number of pages13
JournalPlanta
Volume225
Issue number6
DOIs
StatePublished - May 1 2007

Keywords

  • Glycine
  • Mitogen-activated protein kinase (MAPK) signaling
  • Phytophthora
  • Protein interaction
  • β-Glucan elicitors

ASJC Scopus subject areas

  • Genetics
  • Plant Science

Fingerprint

Dive into the research topics of 'Activation of members of a MAPK module in β-glucan elicitor-mediated non-host resistance of soybean'. Together they form a unique fingerprint.

Cite this