Nep1-like proteins from three kingdoms of life act as a microbe-associated molecular pattern in Arabidopsis

摘要: Necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are secreted by a wide range of plant-associated microorganisms. They best known for their cytotoxicity in dicot plants that leads to the induction rapid tissue necrosis plant immune responses. The biotrophic downy mildew pathogen Hyaloperonospora arabidopsidis encodes 10 different noncytotoxic NLPs (HaNLPs) do not cause necrosis. We discovered these NLPs, however, act as potent activators system Arabidopsis thaliana. Ectopic expression HaNLP3 triggered resistance H. arabidopsidis, activated large set defense-related genes, caused reduction growth is typically associated with strongly enhanced immunity. N- C-terminal deletions HaNLP3, well amino acid substitutions, pinpointed small central region protein required trigger immunity, indicating acts microbe-associated molecular pattern (MAMP). This was confirmed experiments synthetic 24 aa, derived from part corresponding conserved type induces ethylene production, well-known MAMP response. Strikingly, 24-aa peptides fungal bacterial were also able immunity Arabidopsis. widespread phylogenetic distribution makes this family (to our knowledge) first proteinaceous identified three kingdoms life.