Scientists Sequence Calabash Genome

An international team of researchers has produced the first high-quality genome sequence for the bottle gourd, also known as calabash, and reconstructed the genome of the most recent common ancestor of cucurbits (family Cucurbitaceae). The results are published in The Plant Journal.

The high-quality genome sequence of the bottle gourd (Lagenaria siceraria) provides a useful resource for plant comparative genomics studies and cucurbit improvement. Image credit: Alice Paipai.

The bottle gourd (Lagenaria siceraria) is an important vegetable crop as well as a rootstock for other cucurbit crops. It is valued for its numerous practical and culturally-significant uses in food, medicine, and novelties such as musical instruments, utensils, containers, and decorations.

Despite this, a high-quality sequence of the bottle gourd genome has not been available and much of the evolutionary history of modern cucurbits and their genetic relationships remain largely unknown.

In the new study, Boyce Thompson Institute researcher Dr. Zhangjun Fei and co-authors produced a high-quality genome sequence of the bottle gourd and compared it to those of other cucurbit species, allowing them to reconstruct the ancient genomic history of the Cucurbitaceae family.

“Using this genome and other available genomes of cucurbit species including watermelon, melon, cucumber and pumpkin, we reconstructed the genome of the most recent common ancestor of Cucurbitaceae, which provides insights into the paleohistory of the Cucurbitaceae genome evolution,” Dr. Fei said.

The bottle gourd genome sequence also provides a comprehensive collection of the genetic relationships between the bottle gourd and other Cucurbitaceae species, which can be used to accelerate improvements in cucurbit quality and tolerance to stressors such as disease and cold.

“This study will allow researchers to discover novel genes and develop new molecular markers that can be used to breed higher fruit quality and more disease resistant bottle gourd varieties,” Dr. Fei said.

The authors were able to showcase the utility of the genome sequence by locating genes related to one particularly devastating disease, Papaya ring-spot virus (PRSV).

“The high-quality bottle genome has helped map a locus conferring resistance to PRSV, one of the most destructive viruses infecting papaya and cucurbits worldwide,” said co-lead author Dr. Kai-Shu Ling, research plant pathologist at the USDA Agricultural Research Service.

“The genome sequence will undoubtedly facilitate the discovery of additional disease resistance genes and numerous other beneficial traits in bottle gourd.”

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Shan Wu et al. 2017. The bottle gourd genome provides insights into Cucurbitaceae evolution and facilitates mapping of a Papaya ring-spot virus resistance locus. The Plant Journal 92 (5): 963-975; doi: 10.1111/tpj.13722