Engineering the future of Physalis grisea: A focus on agricultural challenges, model species status, and applied improvements

Societal Impact Statement Groundcherry ( Physalis grisea ) is a plant species grown for its flavorful fruit. The fruit drops from the plant, hence the common name groundcherry. This makes harvest cumbersome and puts the fruit at risk for carrying soil‐borne pathogens, therefore making them unsellable. Furthermore, insects often damage the plants, reducing yield. Advances in gene editing offer promise for addressing these issues and aiding home gardeners and farmers. Improvement will expand access to this nutritious fruit, rich in potassium, vitamin C, and antioxidants. Additionally, studies of its biology could serve as a model for improving other fruiting plants, particularly underutilized species. Summary P. grisea is an underutilized, semidomesticated fruit crop with rising agronomic value. Several resources have been developed for its use in fundamental biological research, including a plant transformation system and a high‐quality reference genome. Already, P. grisea has been used as a model to investigate biological phenomena including inflated calyx syndrome and gene compensation. P. grisea has also been used to demonstrate the potential of fast‐tracking domestication trait improvement through approaches such as CRISPR/Cas9 gene editing. This work has led to the Physalis Improvement Project, which relies on reverse genetics to understand the mechanisms that underlie fruit abscission and plant–herbivore interactions to guide approaches for improvement of undesirable characteristics. CRISPR/Cas9 gene editing has been used to target P. grisea genes that are suspected to act in fruit abscission, particularly orthologs of those that are reported in tomato abscission zone development. A similar approach is being taken to target P. grisea genes involved in the withanolide biosynthetic pathway to determine the impact of withanolides on plant–herbivore interactions. Results from these research projects will lead to a greater understanding of important biological processes and will also generate knowledge needed to develop cultivars with reduced fruit drop and increased resistance to insect herbivory.