Worldwide, a tremendous amount of food is lost during harvest, transportation and storage. A reduction of these losses is of major importance for a for a sustainable food security. This challenge is being addressed within the BioSC project RIPE. Its focus lies on the plant hormone ethylene, which influences fruit ripening.
Synthetic peptides derived from proteins involved in the ethylene response provide a promising starting point to delay ripening and senescence of fruits and vegetables and thereby preventing spoilage without the need of transgenic plants. Within the project RIPE, these ripening-inhibiting peptides and their application on different types of fruit will be optimized to promote the potential commercial usage of innovative ripening inhibitors.
So far, the group of Prof. Groth (HHU Düsseldorf) mainly focussed on the molecular understanding of interactions of the synthetic peptides with the ethylene receptor and was able to show which domain is crucial for the interaction. Current protein crystallization studies will provide further insights into the interaction of ripe-inhibiting peptides with proteins of the ethylene pathway. By means of computer-based molecular simulation studies a model of the peptide receptor and various peptide variations were developed by the group of Prof. Gohlke (HHU Düsseldorf). The model enables in silico approaches to analyse peptide specificity and subsequent redesign of peptides for tailored interactions.
The delivery of the ripe-inhibiting peptides to the surface of fruits and vegetables is carried out via microgel containers which are supposed to release the peptides over time. The group of Prof. Pich (RWTH Aachen) was already successful in synthesizing microgels that can bind the synthetic peptide NOP-1 via carboxylic and acid groups. The group of Prof. Schwaneberg (RWTH Aachen) developed specific anchoring peptides which allow for reversible binding of the microgel containers to the fruit surface. The binding poses a challenge since the microgel container has to be resistant to rainfall, but at the same time it must be possible to wash it off before consumption.
Post-harvest experiments were carried out to analyse if the isolated peptide really has the desired effect on the ripening process. Therefore, the group of Prof. Noga (University of Bonn) applied different concentrations of the peptide NOP-1 on the surface of apples and tomatoes and was indeed able to observe a delay of the ripening process. Furthermore it was investigated if the application of peptides has any influence on quality parameters of treated apples and tomatoes. Fortunately that was not the case.
So far the results from the RIPE project are very promising and show that he NOP-1 peptide has the potential to delay fruit ripening while maintaining the fruit quality. This would allow an innovative way to control the ethylene pathway without the need for post-harvest chemicals or transgenic plants.