Gamir, Jordi Darwiche, Rabih Hof, Pieter van't Choudhary, Vineet Stumpe, Michael Schneiter, Roger Mauch, Felix 2017-02-01 Pathogenesis-related proteins played a pioneering role 50 years ago in the discovery of plant innate immunity as a set of proteins that accumulated upon pathogen challenge. The most abundant of these proteins, PATHOGENESIS-RELATED 1 (PR-1) encodes a small antimicrobial protein that has become, as a marker of plant immune signaling, one of the most referred to plant proteins. The biochemical activity and mode of action of PR-1 proteins has remained elusive, however. Here, we provide genetic and biochemical evidence for the capacity of PR-1 proteins to bind sterols, and demonstrate that the inhibitory effect on pathogen growth is caused by the sequestration of sterol from pathogens. In support of our findings, sterol-auxotroph pathogens such as the oomycete Phytophthora are particularly sensitive to PR-1, whereas sterol-prototroph fungal pathogens become highly sensitive only when sterol biosynthesis is compromised. Our results are in line with previous findings showing that plants with enhanced PR-1 expression are particularly well protected against oomycete pathogens. application/pdf https://folia.unifr.ch/global/documents/305452 https://folia.unifr.ch/documents/305452/files/mau_sba.pdf https://folia.unifr.ch/documents/305452/files/mau_sba_sm.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1111/tpj.13398 info:eu-repo/semantics/openAccess License undefined The Plant Journal. - 2017, vol. 89, no. 3, p. 502–509 PR-1 CAP protein antimicrobial protein Phytophthora sterol binding plant immunity info:eu-repo/classification/udc/57 The sterol-binding activity of PATHOGENESIS-RELATED PROTEIN 1 reveals the mode of action of an antimicrobial protein http://purl.org/coar/resource_type/c_6501