RT Journal Article SR Electronic T1 The N Terminus of Bacterial Elongation Factor Tu Elicits Innate Immunity in Arabidopsis Plants JF The Plant Cell JO Plant Cell FD American Society of Plant Biologists SP 3496 OP 3507 DO 10.1105/tpc.104.026765 VO 16 IS 12 A1 Kunze, Gernot A1 Zipfel, Cyril A1 Robatzek, Silke A1 Niehaus, Karsten A1 Boller, Thomas A1 Felix, Georg YR 2004 UL http://www.plantcell.org/content/16/12/3496.abstract AB Innate immunity is based on the recognition of pathogen-associated molecular patterns (PAMPs). Here, we show that elongation factor Tu (EF-Tu), the most abundant bacterial protein, acts as a PAMP in Arabidopsis thaliana and other Brassicaceae. EF-Tu is highly conserved in all bacteria and is known to be N-acetylated in Escherichia coli. Arabidopsis plants specifically recognize the N terminus of the protein, and an N-acetylated peptide comprising the first 18 amino acids, termed elf18, is fully active as inducer of defense responses. The shorter peptide, elf12, comprising the acetyl group and the first 12 N-terminal amino acids, is inactive as elicitor but acts as a specific antagonist for EF-Tu–related elicitors. In leaves of Arabidopsis plants, elf18 induces an oxidative burst and biosynthesis of ethylene, and it triggers resistance to subsequent infection with pathogenic bacteria.