Structural analysis of an Avr4 effector ortholog offers insight into chitin binding and recognition by the Cf-4 receptor

Amanda C. Kohler, Li Hung Chen, Nicholas Hurlburt, Anthony Salvucci, Benjamin Schwessinger, Andrew J Fisher, Ioannis Stergiopoulos

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Chitin is a key component of fungal cell walls and a potent inducer of innate immune responses. Consequently, fungi may secrete chitin-binding lectins, such as the Cf-Avr4 effector protein from the tomato pathogen Cladosporium fulvum, to shield chitin from host-derived chitinases during infection. Homologs of Cf-Avr4 are found throughout Dothideomycetes, and despite their modest primary sequence identity, many are perceived by the cognate tomato immune receptor Cf-4. Here, we determined the x-ray crystal structure of Pf-Avr4 from the tomato pathogen Pseudocercospora fuligena, thus providing a three-dimensional model of an Avr4 effector protein. In addition, we explored structural, biochemical, and functional aspects of Pf-Avr4 and Cf-Avr4 to further define the biology of core effector proteins and outline a conceptual framework for their pleiotropic recognition by single immune receptors. We show that Cf-Avr4 and Pf-Avr4 share functional specificity in binding (GlcNAc)6 and in providing protection against plant- and microbial-derived chitinases, suggesting a broader role beyond deregulation of host immunity. Furthermore, structure-guided site-directed mutagenesis indicated that residues in Pf-Avr4 important for binding chitin do not directly influence recognition by Cf-4 and further suggested that the property of recognition is structurally separated or does not fully overlap with the virulence function of the effector.

Original languageEnglish (US)
Pages (from-to)1945-1965
Number of pages21
JournalPlant Cell
Volume28
Issue number8
DOIs
StatePublished - Aug 1 2016

Fingerprint

Chitin
chitin
Lycopersicon esculentum
Chitinases
receptors
tomatoes
chitinase
Fungal Structures
Dothideomycetes
Passalora fulva
Pseudocercospora
Cladosporium
Proteins
proteins
pathogens
site-directed mutagenesis
crystal structure
Site-Directed Mutagenesis
Lectins
plant protection

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

Cite this

Kohler, A. C., Chen, L. H., Hurlburt, N., Salvucci, A., Schwessinger, B., Fisher, A. J., & Stergiopoulos, I. (2016). Structural analysis of an Avr4 effector ortholog offers insight into chitin binding and recognition by the Cf-4 receptor. Plant Cell, 28(8), 1945-1965. https://doi.org/10.1105/tpc.15.00893

Structural analysis of an Avr4 effector ortholog offers insight into chitin binding and recognition by the Cf-4 receptor. / Kohler, Amanda C.; Chen, Li Hung; Hurlburt, Nicholas; Salvucci, Anthony; Schwessinger, Benjamin; Fisher, Andrew J; Stergiopoulos, Ioannis.

In: Plant Cell, Vol. 28, No. 8, 01.08.2016, p. 1945-1965.

Research output: Contribution to journalArticle

Kohler, AC, Chen, LH, Hurlburt, N, Salvucci, A, Schwessinger, B, Fisher, AJ & Stergiopoulos, I 2016, 'Structural analysis of an Avr4 effector ortholog offers insight into chitin binding and recognition by the Cf-4 receptor', Plant Cell, vol. 28, no. 8, pp. 1945-1965. https://doi.org/10.1105/tpc.15.00893
Kohler, Amanda C. ; Chen, Li Hung ; Hurlburt, Nicholas ; Salvucci, Anthony ; Schwessinger, Benjamin ; Fisher, Andrew J ; Stergiopoulos, Ioannis. / Structural analysis of an Avr4 effector ortholog offers insight into chitin binding and recognition by the Cf-4 receptor. In: Plant Cell. 2016 ; Vol. 28, No. 8. pp. 1945-1965.
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