Brassinosteroids inhibit pathogen-associated molecular pattern-triggered immune signaling independent of the receptor kinase BAK1

Catherine Albrecht, Freddy Boutrot, Cécile Segonzac, Benjamin Schwessinger, Selena Gimenez-Ibanez, Delphine Chinchilla, John P Rathjen, Sacco C de Vries, Cyril Zipfel

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262 Citations (Scopus)


Plants and animals use innate immunity as a first defense against pathogens, a costly yet necessary tradeoff between growth and immunity. In Arabidopsis, the regulatory leucine-rich repeat receptor-like kinase (LRR-RLK) BAK1 combines with the LRR-RLKs FLS2 and EFR in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and the LRR-RLK BRI1 in brassinosteroid (BR)-mediated growth. Therefore, a potential tradeoff between these pathways mediated by BAK1 is often postulated. Here, we show a unidirectional inhibition of FLS2-mediated immune signaling by BR perception. Unexpectedly, this effect occurred downstream or independently of complex formation with BAK1 and associated downstream phosphorylation. Thus, BAK1 is not rate-limiting in these pathways. BRs also inhibited signaling triggered by the BAK1-independent recognition of the fungal PAMP chitin. Our results suggest a general mechanism operative in plants in which BR-mediated growth directly antagonizes innate immune signaling.
Original languageEnglish
Pages (from-to)303-308
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America (PNAS)
Issue number1
Publication statusPublished - 3 Jan 2012


  • Arabidopsis
  • Arabidopsis Proteins
  • Brassinosteroids
  • Enzyme Activation
  • Flagellin
  • Plant Immunity
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • Pseudomonas
  • Receptors, Pattern Recognition
  • Signal Transduction
  • Steroids, Heterocyclic

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