Watermelon Genome Mapped

An international consortium of more than 60 scientists from the U.S., China, and Europe has published the genome sequence of watermelon (Citrullus lanatus). This information could dramatically accelerate watermelon breeding toward production of a more nutritious, tastier, and more disease-resistant fruit. The watermelon genome sequence was published in the Nov. 25 online version of Nature Genetics.

The researchers discovered that a large portion of disease-resistance genes were lost in the domestication of watermelon. With the high-quality watermelon sequence now complete, it is hoped that breeders can now use the information to recover some of these natural disease defenses.

The authors reported that the genome of the domesticated watermelon contained 23,440 genes, roughly the same number of genes as in humans. The group compared the genomes of 20 different watermelons and developed a first-generation genetic variation map for watermelon. This information allowed them to identify genomic regions that have been under human selection, including those associated with fruit color, taste and size.

“Watermelons are an important cash crop and among the top five most consumed fresh fruits; however, cultivated watermelons have a very narrow genetic base, which presents a major bottleneck to its breeding,” said Zhangjun Fei, a scientist at the Boyce Thompson Institute for Plant Research at Cornell University, and one of the leaders of this project. “Decoding the complete genome of the watermelon and resequencing watermelons from different subspecies provided a wealth of information and toolkits to facilitate research and breeding.”

DNA sequence could lead to more nutritious, tastier, and disease-resistant fruit.