Advances and perspectives in biological control of postharvest fungal decay in citrus fruit utilizing yeast antagonists.

Citrus fruits are one of the most highly grown fruit crops worldwide. A significant production problem, however, is their susceptibility to postharvest decay, caused by fungi such as Penicillium spp., resulting in significant losses in marketable yield. Some fungal species also produce mycotoxins that are potentially harmful to humans. Biological control of postharvest decay in citrus utilizing yeast antagonists has been shown to be a promising alternative to the use of synthetic fungicides to address increasingly stringent government regulatory policies and consumer demands. In this current review, we provide an overview of the research conducted on major postharvest decay fungi and their impact on the citrus industry. Then, the isolation and application of yeast antagonists used to manage postharvest decay in citrus is discussed, as well as their mechanisms of action, such as an oxidative burst of reactive oxygen species (ROS), iron depletion, and secondary metabolites. Lastly, the application of recent approaches (e.g., CRISPR/Cas9, RNAi, -omics technologies) in the study of citrus postharvest diseases is reviewed. For biological control to reach its full potential as a key component of an integrated disease management strategy for citrus, additional research will be required to explore the potential use of beneficial microbial consortia. The consortia will need to be comprised of individual core microbial species present in and on citrus fruit throughout its development and that metabolically complement each other in an interacting network.