Affiliation:
1. Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences, Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MOA), , Guangzhou 510640, China
2. College of Horticulture Science, Zhejiang A&F University Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, , Hangzhou 311300, Zhejiang, China
3. Zhejiang A&F University Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, , Hangzhou 311300, Zhejiang, China
Abstract
Abstract
Citrus reticulata ‘Chachi’ (CRC) has long been recognized for its nutritional benefits, health-promoting properties, and pharmacological potential. Despite its importance, the bioactive components of CRC and their biosynthetic pathways have remained largely unexplored. In this study, we introduce a gap-free genome assembly for CRC, which has a size of 312.97 Mb and a contig N50 size of 32.18 Mb. We identified key structural genes, transcription factors, and metabolites crucial to flavonoid biosynthesis through genomic, transcriptomic, and metabolomic analyses. Our analyses reveal that 409 flavonoid metabolites, accounting for 83.30% of the total identified, are highly concentrated in the early stage of fruit development. This concentration decreases as the fruit develops, with a notable decline in compounds such as hesperetin, naringin, and most polymethoxyflavones observed in later fruit development stages. Additionally, we have examined the expression of 21 structural genes within the flavonoid biosynthetic pathway, and found a significant reduction in the expression levels of key genes including 4CL, CHS, CHI, FLS, F3H, and 4′OMT during fruit development, aligning with the trend of flavonoid metabolite accumulation. In conclusion, this study offers deep insights into the genomic evolution, biosynthesis processes, and the nutritional and medicinal properties of CRC, which lay a solid foundation for further gene function studies and germplasm improvement in citrus.
Funder
public research platform of the College of Horticulture Science, Zhejiang A&F University
National Natural Science Foundation of China
Key Project for New Agricultural Cultivar Breeding in Zhejiang Province
the Agricultural Competitive Industry Discipline Team Building Project of Guangdong Academy of Agricultural Sciences
National Modern Agricultural (Citrus) Technology Systems of China
Guangdong Province Science and Technology Plan Project
Publisher
Oxford University Press (OUP)