image: Kordofan watermelon. view more
Credit: Image credit: Shan Wu.
Researchers examine the origin of domesticated watermelons. The geographic origin of the domesticated watermelon, Citrullus lanatus subspecies vulgaris, is unknown. Susanne Renner, Guillaume Chomicki, and colleagues examined ancient imagery of fruits and performed genetic resequencing of the domesticated watermelon and six other Citrullus species. Genetic analyses revealed that the Sudanese Kordofan melon, which has nonbitter whitish pulp, is the closest relative and may be a precursor of domesticated watermelons. Disease-resistance alleles in Kordofan melons differed from those in domesticated watermelons. Comparative genomic analysis of watermelons' bitterness regulator, ClBt, suggested that pulp bitterness may have been lost before domestication, and early farmers may have cultivated nonbitter, wild variants of watermelon. Pulp sweetness likely increased over the course of domestication. The reddish color of pulp, caused by lycopene accumulation, likely resulted from artificial selection. Furthermore, a papyrus illustration from Egypt's 21st dynasty and two Egyptian tomb paintings dating to around 4,450 years ago portrayed imagery of oblong fruit with dark green stripes. These watermelon-like objects were depicted on trays and tables with other sweet foods, such as grapes, suggesting that sweet watermelon, possibly derived from Kordofan melons, was consumed in ancient Egypt's Nile Valley. Insights gleaned from the Kordofan melon genome may aid watermelon breeding, according to the authors.
Article #21-01486: "A chromosome-level genome of a Kordofan melon illuminates the origin of domesticated watermelons," by Susanne S. Renner et al.
MEDIA CONTACT: Susanne S. Renner, Washington University in St. Louis, MO; tel: 314-465-5688; email: renner@lmu.de; Guillaume Chomicki, University of Sheffield, UNITED KINGDOM, email: g.chomicki@sheffield.ac.uk
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Journal
Proceedings of the National Academy of Sciences