Cytosolic Nudix Hydrolase 1 Is Involved in Geranyl β-Primeveroside Production in Tea
Bibliographic record
Abstract
Geraniol is a potent tea odorant and exists mainly as geranyl glycoside inCamellia sinensis. Understanding the mechanisms of geraniol biosynthesis at molecular levels in tea plants is of great importance for practical improvement of tea aroma. In this study, geraniol and its glycosides from tea plants were examined using liquid chromatography coupled with mass spectrometry. Two candidate geraniol synthase (GES) genes (CsTPS) and two Nudix hydrolase genes (CsNUDX1-cytoandCsNUDX1-chlo) from the tea genome were functionally investigated through gene transcription manipulation and gene chemical product analyses. Our data showed that in tea leaves, levels of geranylβ-primeveroside were dramatically higher than those of geranylβ-glucoside, while free geraniol was undetectable in this study. A tempo-spatial variation of geranylβ-primeveroside abundance in tea plants existed, with high levels in young and green tissues and low levels in mature or non-green tissues. Cytosolic CsNUDX1-cyto showed higher hydrolysis activity of geranyl-pyrophosphate to geranyl-monophosphate (GP)in vitrothan did chloroplastidial CsNUDX1-chlo. A transgenic study revealed that expression ofCsNUDX1-cytoresulted in significantly more geranylβ-primeveroside in transgenicNicotiana benthamianacompared with non-transgenic wild-type, whereas expression ofCsNUDX1-chlohad no effect. An antisense oligo-deoxynucleotide study confirmed that suppression ofCsNUDX1-cytotranscription in tea shoots led to a significant decrease in geranylβ-primeveroside abundance. Additionally,CsNUDX1-cytotranscript levels and geranylβ-primeveroside abundances shared the same tempo-spatial patterns in different organs in the tea cultivar “Shucha Zao,” indicating thatCsNUDX1-cytois important for geranylβ-primeveroside formation in tea plants. Results also suggested that neither of the two candidate GES genes in tea plants did not function as GES in transgenicN. benthamiana. All our data indicated thatCsNUDX1-cytois involved in geranylβ-primeveroside production in tea plants. Our speculation about possible conversion from the chemical product of CsNUDX1-cyto to geranylβ-primeveroside in plants was also discussed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".