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The sterol‐binding activity of PATHOGENESIS‐RELATED PROTEIN 1 reveals the mode of action of an antimicrobial protein
Author(s) -
Gamir Jordi,
Darwiche Rabih,
Hof Pieter,
Choudhary Vineet,
Stumpe Michael,
Schneiter Roger,
Mauch Felix
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13398
Subject(s) - oomycete , sterol , biology , innate immune system , mode of action , pathogenesis , pathogen , microbiology and biotechnology , antimicrobial , biochemistry , receptor , genetics , immunology , cholesterol
Summary 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.