Journal of Tea Science Research, 2024, Vol.14, No.6, 335-343 http://hortherbpublisher.com/index.php/jtsr 335 Research Perspective Open Access Key Genetic Pathways Regulating Flavonoid Biosynthesis in Tea Plants Yufen Wang, Xiaocheng Wang Traditional Chinese Medicine Research Center, Cuixi Academy of Biotechnology, Zhuji, 311800, Zhejiang, China Corresponding author: xiaocheng.wang@cuixi.org Journal of Tea Science Research, 2024, Vol.14, No.6 doi: 10.5376/jtsr.2024.14.0031 Received: 18 Oct., 2024 Accepted: 27 Nov., 2024 Published: 16 Dec., 2024 Copyright © 2024 Wang and Wang, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Wang Y.F., and Wang X.C., 2024, Key genetic pathways regulating flavonoid biosynthesis in tea plants, Journal of Tea Science Research, 14(6): 335-343 (doi: 10.5376/jtsr.2024.14.0031) Abstract Flavonoids constitute a very extensive group of secondary metabolites in Camellia sinensis that are of importance in determining the quality and health impacts of tea for the consumers. Flavonoids are responsible for the coloring of the leaves, bitterness, and antioxidant activity, which determine the tea's pharmacological effects like anti-inflammatory, cardioprotective, and anticancer activities. The biosynthesis of flavonoid in tea is an extremely interactive system of structural genes, transcription factors, and regulatory pathways traced back to the phenylpropanoid metabolism. The recent research development on omics technologies has enhanced the understanding of the key enzymes, gene expression pattern, and molecular regulating mechanisms involved in flavonoid biosynthesis. Other significant fields of this network are transcriptional and epigenetic regulation, the functions of which are played by non-coding RNAs. This study presents a brief overview of flavonoids in tea varieties, their biosynthetic processes, and genetic control of their accumulation, along with the use of multi-omics tools, potential strategies to enhance content of flavonoid through molecular breeding and biotechnology. These results will profit both plant secondary metabolism scientific knowledge and tea cultivar breeding with high-quality, health-promoting traits. Keywords Flavonoids; Camellia sinensis; Biosynthetic pathways; Transcriptional regulation; Molecular breeding 1 Introduction Flavonoids are among the most abundant and functionally significant secondary metabolites in Camellia sinensis (tea plant). These polyphenolic compounds are integral to the quality and physiological attributes of tea leaves, contributing to coloration (such as the purple hue in anthocyanin-rich cultivars), bitterness, astringency, and antioxidant capacity. Catechins, the dominant flavonoids in tea, are directly associated with the health-promoting effects of green tea, while other subclasses like flavonols and anthocyanins influence both sensory characteristics and adaptive responses to environmental stimuli. In planta, flavonoids serve as essential agents in UV protection, pathogen resistance, and stress mitigation, underscoring their biological and ecological importance in tea cultivation (Li et al., 2022). Beyond their role in plant physiology, tea flavonoids offer a wide range of nutritional and therapeutic benefits to humans. Extensive research has demonstrated their antioxidant, anti-inflammatory, cardioprotective, neuroprotective, and anticancer properties. Catechins such as epigallocatechin gallate (EGCG) have been particularly well-studied for their ability to scavenge free radicals, modulate cell signaling pathways, and influence metabolic health. The regular consumption of flavonoid-rich tea has been linked to reduced risks of chronic diseases, including cardiovascular disease, obesity, and certain cancers, making them key functional compounds in human nutrition and preventive medicine (Wang et al., 2021; Lv et al., 2022). Because of their central roles in both human and plant health, clarification of the biosynthetic and regulatory mechanisms of flavonoids in tea plants has great interest. The flavonoid biosynthetic pathway is complex with multiple branches originated from the phenylpropanoid pathway and tightly controlled by networks of structural genes, transcription factors, and post-transcriptional regulators. The recent advances in genomics, transcriptomics, and metabolomics have enabled the identification of key genes and regulatory factors, yet the general knowledge of how these networks are controlled—especially under environmental and developmental cues—is still absent.
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