Amino acids are among the most important quality-related metabolites in tea plants, accounting for a notable proportion of the dry weight of young shoots and strongly influencing taste and functional properties. Theanine, a tea-characteristic amino acid, is synthesized from glutamate and ethylamine, making nitrogen assimilation a key process in tea quality formation. Glutamate synthase (GOGAT) is a central enzyme in this pathway, but how its expression is controlled after transcription has remained poorly understood. Compared with protein-coding genes, non-coding RNA regulation in woody crops is still underexplored. Due to these challenges, in-depth research is needed on RNA-layer regulation of amino acid biosynthesis in tea plants.
The study was conducted by researchers from Yunnan Agricultural University and Anhui Agricultural University and was published (DOI: 10.1093/hr/uhag014) on January 13, 2026, in Horticulture Research. Focusing on tea plant (Camellia sinensis), the team investigated how a competitive endogenous RNA (ceRNA) module involving lncR12304.1, miR1507c, and CsNADH-GOGAT regulates nitrogen metabolism and amino acid accumulation. The findings show that this RNA module connects nitrogen response with the biosynthesis of glutamate and theanine, providing experimental evidence for a post-transcriptional regulatory mechanism in tea quality formation.
The researchers first identified miR1507c as a direct regulator of CsNADH-GOGAT using dual-luciferase reporter (DLR) assays and 5′ RNA ligase-mediated rapid amplification of cDNA ends (5′ RLM-RACE). When miR1507c was overexpressed, CsNADH-GOGAT expression was suppressed, confirming that miR1507c can cleave or repress this key gene. The team then used long non-coding RNA (lncRNA) sequencing to screen for lncRNAs that could interact with miR1507c and selected lncR12304.1 because of its nitrogen responsiveness and predicted binding strength. Fluorescence in situ hybridization (FISH) showed that lncR12304.1 and miR1507c co-localized mainly in the cytoplasm, where ceRNA interactions usually occur. RNA pull-down quantitative polymerase chain reaction (qPCR) further confirmed that miR1507c binds both lncR12304.1 and CsNADH-GOGAT. In tea shoots and roots treated with different nitrogen levels, lncR12304.1 and CsNADH-GOGAT showed largely positive expression patterns, while miR1507c showed an opposite trend. Suppressing miR1507c increased lncR12304.1, CsNADH-GOGAT, glutamate, and theanine levels, and transient tobacco assays supported the same regulatory relationship.
The authors said the study shows that tea flavor chemistry is not controlled only by enzymes or transcription factors, but also by a hidden RNA dialogue that determines whether key amino acid genes can function efficiently. They said lncR12304.1 appears to buffer the inhibitory effect of miR1507c, allowing CsNADH-GOGAT to support glutamate and theanine biosynthesis. This provides a clearer view of how tea plants translate nitrogen availability into quality-related metabolites and opens a new route for understanding the molecular basis of taste formation.
These findings may help accelerate molecular breeding of tea cultivars with richer amino acid profiles and more stable quality under different nitrogen conditions. Because theanine and glutamate contribute directly to desirable taste characteristics, the lncR12304.1–miR1507c–CsNADH-GOGAT module could become a useful marker or target for future quality improvement. The work also broadens the study of ceRNA regulation in woody crops, where functional validation remains limited. Future research measuring CsNADH-GOGAT protein abundance and enzyme activity, together with stable genetic systems, will be important for translating this RNA mechanism into practical breeding and cultivation strategies.
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References
DOI
10.1093/hr/uhag014
Original Source URL
https://doi.org/10.1093/hr/uhag014
Funding information
This study was supported by the Yunnan Provincial Basic Research Programs (202201AT070253, 202501AS070039), Yunnan Provincial Basic Research Agriculture (202401BD070001-044, 202401BDO70001-007), the Open Fund of State Key Laboratory of Tea Plant Biology and Utilization (NKLTOF20240110), and the Anhui Provincial Natural Science Foundation (2408085MC077).
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, 2023. 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.