Decoding chieh-qua: Unveiling the genetic secrets of a cultivated cucurbit

A pivotal study has successfully sequenced and assembled the chromosome-level genome of chieh-qua, a cucurbit crop with significant economic and cultural importance in Asia. The high-quality genome assembly provides a comprehensive genetic blueprint, revealing the crop's genetic diversity and evolutionary history. This achievement is instrumental for advancing molecular breeding and understanding the genetic basis of chieh-qua's unique traits, such as subgynoecy, which is vital for crop yield and cultivation efficiency.

Despite chieh-qua's economic and nutritional significance in South China and Southeast Asia, its genetic foundation and domestication history remain unclear. Previous research has primarily focused on other cucurbits like cucumber and melon, leaving a gap in understanding chieh-qua. The lack of genomic information hinders molecular breeding advancements for this crop. Due to these challenges, a detailed study of chieh-qua’s genome is necessary to uncover its genetic secrets and enhance breeding programs. Consequently, this research aims to fill that gap and provide critical insights into chieh-qua's genetic makeup.

A team of researchers from the Guangdong Academy of Agricultural Sciences and China National Rice Research Institute published their findings (DOI: 10.1093/hr/uhae113) in Horticulture Research on April 22, 2024. The study details the successful generation of a chromosome-level reference genome assembly for chieh-qua using a combination of PacBio long reads and Illumina short reads. This assembly provides valuable genomic resources and insights into chieh-qua's domestication history and genetic diversity.

The research team successfully assembled the chieh-qua genome, which is approximately 953.3 Mb in size and organized into 12 chromosomes. They identified 24,593 protein-coding genes and found that 56.6% of the genome consists of repetitive sequences. Comparative analysis revealed a close evolutionary relationship between chieh-qua and wax gourd, highlighting their genetic similarities. Population genomic analysis of 129 chieh-qua accessions showed greater genetic diversity compared to wax gourd. Using genome-wide association studies (GWAS), the researchers identified quantitative trait loci (QTLs) linked to subgynoecy, a trait that enhances female flower production and yield. The MYB59 gene, in particular, exhibited high expression levels in subgynoecious varieties, making it a key candidate for further research. This study provides a comprehensive understanding of chieh-qua's genetic makeup, offering valuable resources for future genetic and breeding research aimed at improving crop yield and quality.

Dr. Songguang Yang, a leading researcher, stated, "This study provides a high-quality genome assembly for chieh-qua, offering invaluable resources for future genetic and breeding research. The identification of key traits such as subgynoecy will significantly impact the cultivation and yield improvement of this important crop."

The insights gained from this study pave the way for advanced molecular breeding programs aimed at improving chieh-qua's yield and stress tolerance. The genomic resources developed will also facilitate further research into other economically important traits, ultimately benefiting farmers and consumers in South China and Southeast Asia.

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References

DOI

10.1093/hr/uhae113

Original Source URL

https://doi.org/10.1093/hr/uhae113

Funding information

This work was funded by the National Natural Science Foundation of China (32002038), Special Fund for Scientific Innovation Strategy-construction of High-Level Academy of Agricultural Science (R2021PY-QF008), Agricultural Competitive Industry Discipline Team Building Project of Guangdong Academy of Agricultural Sciences (202114TD, 202103TD).

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2022. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.