Yuji Ono

Discovery of a Small Peptide from Combinatorial Libraries That Can Activate the Plant Immune System by a Jasmonic Acid Signaling Pathway

Plants defend themselves by using an innate immune system that is activated in response to a variety of molecules derived from pathogens. These molecules have provided profound insights into the mechanisms of pathogen recognition and subsequent signaling pathways in plants. In the present study, we screened a combinatorial random hexapeptide library for peptides that activate the plant immune system, by using a cell‐based high‐throughput screening system in which H2O2 generation was monitored. We discovered a novel small peptide (YGIHTH‐amide, PIP‐1) that triggered H2O2 production in tobacco and tomato cells, but not in Arabidopsis cells. PIP‐1 induced significant levels of phytoalexin biosynthesis and defense‐related gene expression in tobacco cells; this is likely to be activated by a jasmonic acid pathway.