Deciphering the genome of cornus wilsoniana: A leap towards understanding oil biosynthesis and floral development

Cornus wilsoniana W., a valuable woody oil plant native to China, is known for its high oil content and hypolipidemic effects. Despite its economic and ecological importance, research has been hampered by the lack of detailed genomic information, specifically a chromosome-level reference genome. This gap limits understanding of the molecular mechanisms behind its oil biosynthesis. Initial studies have made some progress, but comprehensive genomic research is crucial for uncovering the genetic basis of oil production in C. wilsoniana and optimizing its use as a dietary and medicinal resource.

In September 2023, Horticulture Research published a research entitled by “A chromosome-level genome assembly provides insights into Cornus wilsoniana evolution, oil biosynthesis, and floral bud development”.

In this study, researchers first collected fresh young leaves of C. wilsoniana from Guangdong, China, and a draft genome assembly of C. wilsoniana was created using PacBio and Hi-C data. Based on the chromosome-level assembly of the 11 chromosomal anchors, the genome size was estimated to be 843.51 Mb. The calculated N50 contig size and N50 scaffold size were 4.49 and 78.00 Mb, respectively. In addition, 30,474 protein-coding genes were also annotated. This high-quality assembly was validated against physical chromosome lengths, showing a high degree of accuracy and completeness, with 97.71% of core genes identified. Comparative genomics with 19 species illuminated the evolutionary relationships and identified specific gene families in C. wilsoniana, highlighting its close relation to C. controversa and shared whole-genome duplication (WGD) events. The research further infered the origin of the chromosomes, thus revealing the complex evolutionary history of the C. wilsoniana karyotype.

Key genes involved in oil biosynthesis were identified, showing a significant number of genes related to acyl lipid synthesis. Through manual examination and database searches, 80 candidate genes for fatty acid and triacylglycerol biosynthesis were pinpointed, with 55 showing expression in various tissues. Transcriptional and metabolic analyses identified two FAD2 homologous genes, which may play crucial roles in controlling the ratio of oleic acid to linoleic acid. The correlation between metabolites and genes was further investigated, and 33 MADS-TF homologous genes that may affect Wilson flower morphology were identified. This revealed key transcription factors and pathways involved in flower formation, offering insights into the genetic control of floral traits.

Overall, this research provides a valuable genomic resource for understanding the genetic basis of important traits in C. wilsoniana, including oil biosynthesis and floral bud development. It lays the foundation for future breeding efforts to enhance these traits and explores the plant's evolutionary history, highlighting its significance in the study of plant genomics and evolution.

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References

Authors

Zhenxiang He1,†, Haoyu Chao1,2,†, Xinkai Zhou1,†, Qingyang Ni2, Yueming Hu2, Ranran Yu1, Minghuai Wang3, Changzhu Li4, Jingzhen Chen4, Yunzhu Chen4, Yong Chen5, Chunyi Cui6, Liangbo Zhang4,7,*, Ming Chen2,* and Dijun Chen1,*

†Equal contributions and joint first authors.

Affiliations

¹State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China

²Department of Bioinformatics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China

³Forest Protection Department, Guangdong Academy of Forestry, Guangzhou 510520, China

⁴State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, China

⁵Xishan Forest Farm, Dazu District, Chongqing 402360, China

⁶Longshan Forest Farm, Lechang 512221, China

⁷Hunan Horticultural Research Institute, Hunan Academy of Agricultural Sciences, Changsha 410125, China

About  Dijun Chen

 Associate Professor, School of Life Sciences, Nanjing University. Mainly engaged in bioinformatics research on gene transcription regulation.