Interfering Peptides Targeting Protein-Protein Interactions in the Ethylene Plant Hormone Signaling Pathway as Tools...

Interfering peptides (iPs) have been recognized as valuable substances to specifically target protein-protein interactions (PPIs) in senescence and disease. Although the concept of iPs has been validated for several PPIs in medical and pharmaceutical research, little attention so far has been paid to the enormous potential iPs that may provide to target and control plant growth and developmental processes or plant environmental responses. However, recent research on PPIs in the ethylene signaling pathway has identified the synthetic peptide NOP-1 derived from the nuclear localization signal of ethylene regulator EIN2 as an efficient inhibitor of typical ethylene responses such as ripening, aging, and senescence. Biophysical and biochemical studies on purified recombinant proteins of the ethylene receptor family from various plant species demonstrate that the synthetic peptide binds in the nM-μM range at the plant target. Here, we describe methods to evaluate and quantify the effect of the NOP-1 peptide on flower senescence as a typical ethylene response in the intact plant system. This approach will help to systematically advance our technological capability to delay plant ethylene responses and to expand shelf-life or vase life of fruits and flowers.