Nearly half of all fresh fruits and vegetables are lost between harvest and consumption. In the United States, an estimated 38.2 billion pounds of fruit and vegetables are lost annually at retail and consumer levels. Fungal infections causing decay significantly contribute to these losses. Chemical fungicides are currently the leading solution, but growing concerns over their health and environmental impacts have fuelled the search for safer alternatives.
BARD-funded research led by Dr. Noam Alkan from the Department of Postharvest Science at ARO and Dr. Dilip Shah from the Danforth Plant Science Center focused on plant-derived antifungal nodule-specific cysteine-rich peptides (NCRs) that originate from legume nodules during symbiotic relationship with rhizobia. Several small NCRs with cationic charge were found to have potent antifungal activity against several postharvest pathogenic fungi, including Alternaria, Lasiodiplodia, Botrytis, and Penicillium.
The NCR13 mode of action was studied against Alternaria and found to initiate through rapid attachment to the fungal membrane, breaking through, and entering the cell. Inside, it disrupts essential systems including energy production, oxidative balance, cellular respiration, and the cell wall, ultimately leading to fungal cell death.
To protect the peptide and make it more effective, we engineered microscopic calcium carbonate particles to encapsulate it. These porous, naturally degradable particles protect the peptide from environmental damage and release it over time. Additionally, the fruit could absorb calcium ions during the peptide release, offering additional benefits. By adjusting the size, shape, surface charge, and coating of the particles, we can control the peptide release, depending on the specific application.
Currently, antifungal peptides are not used postharvest. This combination of plant-derived antifungal peptides and particle delivery provides a promising, eco–friendly solution for reducing postharvest waste and extending the shelf life of fresh produce, without relying on synthetic chemicals.
This image illustrates an eco-friendly antifungal approach using calcium carbonate particles (C) to deliver NCR peptides (P) onto fruit surfaces (S). These particles release the peptides over time, allowing them to penetrate fungal cells (F). Inside the cell, the peptides disrupt key structures and processes, such as the membrane (M), mitochondria (Mi), nucleus (N), and oxidative burst (R)—ultimately leading to fungal death. This method offers a sustainable alternative to chemical fungicides for postharvest protection.
