Metabolite and transcriptome profiling of russeted and waxy apple skins highlighted genes involved in triterpene-hydroxycinnamate biosynthesis
Bibliographic record
Abstract
Pentacyclic triterpenes possess numerous biomedical properties, including anti-inflammatory, anti-cancer, and anti-plasmodial activities. Esterification of triterpenic acids with hydroxycinnamic acids such as caffeic acid has been shown to increase their biological potential. In previous studies, we showed that russeted old heritage apple varieties are characterized by the accumulation of suberin in skin tissues [1], which present higher concentrations of specific triterpene esters such as betulinic acid-3- trans -caffeate [2] ( Figure 1 ) as compared to their waxy-skinned counterparts. Knowledge on the molecular events associated with triterpene-caffeate production is however still lacking, although it could be therapeutically of major interest. For that purpose, apple fruits from two nearly isogenic yet contrasting varieties, i.e . 'Reinette du Canada Gris' (russeted skin) and 'Reinette du Canada Blanc' (waxy skin), were collected at five time points during the 2013 growing season. Metabolomics data were obtained by Ultra-Performance Liquid chromatography hyphenated with a high-resolution mass spectrometer (UPLC-TripleTOF HR-MS) and compared with whole gene expression profiling data (RNA-Seq). For both cultivars, wax components (including triterpenes) increased until 99 days after full bloom (DAFB) and remained at the same level until commercial maturity (150 DAFB), while specific triterpene esters in russeted tissues continuously increased through fruit growth. This increase was associated with enhanced expression of suberin-related genes and of hydroxycinnamoyl-CoA transferases potentially implicated in triterpene-caffeates biosynthesis. The phenylpropanoid pathway appeared also differentially regulated, with higher amounts of hydroxycinnamic acid derivatives accumulating in russeted skins. Taken together, these results provide important information for the large scale in vitro production of specific apple triterpenes via bioengineering approaches. Fig. 1: Chemical structure of betulinic acid-3- trans -caffeate. Acknowledgements: We thank Marc Lateur (Centre de Recherches Agronomiques, Gembloux, Belgium) for providing apple cultivars. Sylvain Legay is supported by the Fond National de la Recherche Luxembourg (Doctoral grant AFR 9208308).
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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".