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Societal Impact StatementGroundcherry (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. SummaryP. griseais 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. griseahas been used as a model to investigate biological phenomena including inflated calyx syndrome and gene compensation.P. griseahas 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 thePhysalisImprovement 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 targetP. griseagenes 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 targetP. griseagenes 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.
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Repeated evolution of a morphological novelty: a phylogenetic analysis of the inflated fruiting calyx in the Physalideae tribe (Solanaceae)
Premise of the StudyThe evolution of novel fruit morphologies has been integral to the success of angiosperms. The inflated fruiting calyx, in which the balloon‐like calyx swells to completely surround the fruit, has evolved repeatedly across angiosperms and is postulated to aid in protection and dispersal. We investigated the evolution of this trait in the tomatillos and their allies (Physalideae, Solanaceae). MethodsThe Physalideae phylogeny was estimated using four regions (ITS,LEAFY,trnL‐F,waxy) with maximum likelihood (ML) and Bayesian inference. Under the best‐fittingMLmodel of trait evolution, we estimated ancestral states along with the numbers of gains and losses of fruiting calyx accrescence and inflation with Bayesian stochastic mapping. Also, phylogenetic signal in calyx morphology was examined with two metrics (parsimony score and Fritz and Purvis'sD). Key ResultsBased on our well‐resolved and densely sampled phylogeny, we infer that calyx evolution has proceeded in a stepwise and directional fashion, from non‐accrescent to accrescent to inflated. In total, we inferred 24 gains of accrescence, 24 subsequent transitions to a fully inflated calyx, and only two reversals. Despite this lability, fruiting calyx accrescence and inflation showed strong phylogenetic signal. ConclusionsOur phylogeny greatly improves the resolution of Physalideae and highlights the need for taxonomic work. The comparative analyses reveal that the inflated fruiting calyx has evolved many times and that the trajectory toward this phenotype is generally stepwise and irreversible. These results provide a strong foundation for studying the genetic and developmental mechanisms responsible for the repeated origins of this charismatic fruit trait.
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- Award ID(s):
- 1553114
- PAR ID:
- 10462897
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- American Journal of Botany
- Volume:
- 106
- Issue:
- 2
- ISSN:
- 0002-9122
- Format(s):
- Medium: X Size: p. 270-279
- Size(s):
- p. 270-279
- Sponsoring Org:
- National Science Foundation
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