On 10 July 2024, Nature published RESEARCH HIGHLIGHT on “How the watermelon got its sweet taste and rosy hue, Genomic analysis reveals the complex roots of the modern fruit.” (doi: https://doi.org/10.1038/d41586-024-02265-0)

The following is take from the Nature RESEARCH HIGHLIGHT.

Some of the ancestors of the watermelon were not as sugar-laden as the fruit sold today. Credit: Visual China Group/Getty

 

Scientists have mapped the genomes of watermelon and their wild — and often bitter — relatives in unprecedented detail, in the hope of breeding better fruit.

Watermelons (Citrullus lanatus) were domesticated in Africa. To better understand the fruit’s domestication history, and the basis for traits such as its sweetness, Yilin Zhang, at the Peking University Institute of Advanced Agricultural Sciences in Weifang, China, and his colleagues generated ‘gapless’ genomes of 27 varieties and wild relatives of watermelons.

Previous studies have suggested that the fruit was domesticated from the Kordofan melon (C. lanatus subsp. cordophanus), a white-fleshed relative from Sudan that tastes like a cucumber. But the genome analysis found signs of a more complex domestication history — one that also involved Citrullus mucosospermus, a semi-wild relative harvested in West Africa.

The genome analysis also suggests that domesticating watermelons led to the amplification of genes involved in sugar accumulation and in producing the fruit’s pinky-red colour. But it suggests, too, that the process led to the loss of genes that are involved in disease resistance and are present in wild relatives. The new genomes could help breeders to identify and reintroduce useful traits into cultivated watermelons, the researchers say.

The full paper was published in Nature Genetics: 

Zhang, Y. et al. Telomere-to-telomere Citrullus super-pangenome provides direction for watermelon breeding. Nature 631, 713 (2024) 

https://doi.org/10.1038/s41588-024-01823-6.