Recently, the Tea Eco-Cultivation Team from the Tea Research Institute of Chinese Academy of Agricultural Sciences has made important progress in elucidating the mechanisms of bitter compound metabolism and temperature adaptation in tea plants during spring warming. The research findings, titled “Multi-omics profiling of Camellia sinensis reveals mechanisms of bitter metabolism and temperature adaptation during spring warming,” has been published in the journal Industrial Crops & Products.

Spring temperature fluctuations - increasingly common under global climate change -significantly affect tea plant growth and quality formation. In particular, the metabolism of bitter compounds in tea is highly temperature-sensitive, directly affecting taste and economic value. In this study, the researchers used a conventional green-leaf cultivar ‘Longjing 43’, a temperature-sensitive albino cultivar ‘Baiye 1’, and a light- and temperature-sensitive albino cultivar ‘Zhonghuang 2’ as materials to systematically investigate the effects of spring temperature fluctuations on the biosynthesis of flavonoid bitter compounds in tea plant.

By integrating metabolomic and transcriptomic analyses, the researchersclarified how temperature regulates the accumulation of bitter compounds such as quercetin glycosides and kaempferol glycosides, along with their underlying molecularnetworks. The results showed that ‘Longjing 43’ enhances the accumulation of quercetin glycosides at 30℃ by upregulating the expression of the F3'5'H gene, leading to increased bitterness. In contrast, ‘Baiye 1’ accumulates kaempferol glycosides at 20℃ to mitigate the bitter and astringent taste caused by catechins. ‘Zhonghuang 2’ exhibited a “transcription - metabolism decoupling” phenomenon, reflecting a metabolic adaptation mechanism under the synergistic regulation of both light and temperature.

On this basis, a metabolic - transcriptional regulatory network for bitter compound biosynthesis was constructed using weighted gene co-expression network analysis (WGCNA), and the key transcription factors CsMYB1 and CsERF2 were identified. Functional validation using antisense oligonucleotide (AsODN) silencing confirmed that these two genes positively regulate catechin biosynthesis. This study not only deepens our understanding of the temperature-responsive mechanisms of bitter metabolism in tea plants, but also provides important theoretical support for breeding high-quality, stress-resistant tea cultivars and for addressing the challenges posed by climate change.

The study was supported by the Natural Science Foundation of Zhejiang Province, the National Natural Science Foundation of China, the National Key R&D Program of China, and the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences. Jingbo Yu (PhD student), Wenli Wang and Keyin Shen (graduate student) are co-first authors. Corresponding authors are Prof. Xin Li and Assistant Researcher Rongxiu Yin are co-corresponding authors.