Sesquiterpene valencene is dominant in flavedo tissues of sweet oranges and imparts a unique woody aroma. However, the interaction between the biosynthetic pathways of valencene and other nutritional compounds is less studied. Sesquiterpenoids were significantly accumulated in a previously reported glossy mutant of orange (MT) than the wild type (WT), especially valencene and caryophyllene. In addition, we identified several other pathways with variations at both the transcriptional and metabolic levels in MT. It's interesting to found those up-regulated metabolites in MT, such as eukaryotic lipids, kaempferol and proline also showed strong positive correlation with valencene along with fruit maturation while those down-regulated metabolites, such as phenylpropanoid coumarins and most of the modified flavonoids exhibited negative correlation. We then categorized these shifted pathways into the ‘sesquitepenoid-identical shunt’ and the sesquitepenoid-opposite shunt’ and confirmed the classification result at transcriptional level. Our results provide important insights into the connections between various fruit quality-related properties.
Yu Shi,Jinduo Cheng,Ruihua Ding,Pu Wang,Xiaochao Xiong,Weili Hong
Understanding metabolic heterogeneity and dynamics is crucial for optimizing microbial production of valuable chemicals in synthetic biology. However, current quantification methods often lack single-cell resolution or require destructive sampling. Here, we report engineering valencene-producing Yarrowia lipolytica ( Y. lipolytica ) and integrate hyperspectral stimulated Raman scattering (SRS) microscopy, a label-free and non-invasive imaging technique, with a Lasso unmixing algorithm to quantify valencene biosynthesis at the single-cell level, revealing previously unresolved metabolic heterogeneity in production yields. To demonstrate the utility of this approach, we perform time-resolved tracking of valencene metabolism and a substrate co-feeding strategy, which reveals that cells preferentially utilize acetic acid rather than glucose for valencene biosynthesis. In addition, by optimizing the carbon/nitrogen (C/N) ratio in the nutrient and applying fed-batch cultivation, the valencene yield is further increased to 125 mg/L. This work establishes hyperspectral SRS microscopy as a powerful tool for in situ visualization of microbial metabolism, offering a label-free and non-destructive alternative to current destructive methods in synthetic biology.
危险品化学品经营许可证（带存储）