Development of a high-throughput screening method using a cell-based, lawn format assay for the identification of novel plant defense activators from combinatorial peptide libraries

Photolabile Linkers for Solid-Phase Synthesis

Photolabile linkers are the subjects of intense research because they allow the release of the target molecule simply by irradiation. Photochemical release of synthesis products is often facilitated without additional reagents under mild reaction conditions, which may even be environmentally friendly and appealing in the context of greener chemistry. The mild conditions also allow for applications of released material in subsequent biological screening experiments, where contamination with cleavage reagents would be detrimental. This Review pays attention to the increasing number of photolabile linkers developed for solid-phase synthesis and release and covers: (i) o-nitrobenzyloxy linkers, (ii) o-nitrobenzylamino linkers, (iii) α-substituted o-nitrobenzyl linkers, (iv) o-nitroveratryl linkers, (v) phenacyl linkers, (vi) p-alkoxyphenacyl linkers, (vii) benzoin linkers, (viii) pivaloyl linkers, and (ix) other photolabile linkers.

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 H(2)O(2) generation was monitored. We discovered a novel small peptide (YGIHTH-amide, PIP-1) that triggered H(2)O(2) 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.