Metabolic Regulation Profiling of Carbon and Nitrogen in Tea Plants [Camellia sinensis (L.) O. Kuntze] in Response to Shading

Abstract

Manipulating light transmission by shading is the most effective method of improving the nutritional value and sensory qualities of tea. In this study, the metabolic profiling of two tea cultivars (“Yulv” and “Maotouzhong”) in response to different shading periods during the summer season was performed using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS) and gas chromatography-mass spectrometry (GC-MS). The metabolic pathway analyses showed that the glycolytic pathway and the tricarboxylic acid cycle (TCA cycle) in the leaves and shoots of “Maotouzhong” were significantly inhibited by long-term shading. The nitrogen metabolism in the leaves of the two cultivars was promoted by short-term shading, while it was inhibited by long-term shading. However, the nitrogen metabolism in the shoots of the two cultivars was always inhibited by shading, whether for short or long-term periods. In addition, the intensity of the flavonoid metabolism in both tea cultivars could be reduced by shading. These results revealed that shading could regulate the carbon and nitrogen metabolism and short-term shading could improve the tea quality to some extent.

Between Light and Shading: Morphological, Biochemical, and Metabolomics Insights Into the Influence of Blue Photoselective Shading on Vegetable Seedlings

“…The influence of blue light quality and intensity on plant metabolism has been previously confirmed through the metabolomic and transcriptomic approaches that revealed that low-intensity blue light, medium-intensity blue light, and high-intensity blue light triggered a reprogramming in essential physiological processes and secondary metabolism ( Wang P. et al, 2020 ). Moreover, it has been reported that shading alters nitrogen and carbon metabolism, which explains the changes observed at the biochemical level and is supported by the nitrate concentration data under shading ( Li et al, 2020 ; Table 4 ).…”

“…Previously studies reported that energy metabolism was affected by shading. In particular, Li et al (2020) observed a decrease in sugar content and suggested a lower need for energy under shading conditions that lead to changes in carbon flux from the synthesis of glucose to a feedback mechanism by shifting stored glucose to amino acid metabolism instead of normal carbon metabolism.…”

“…This repression is reflected in the marked down accumulation of nitrogen-containing compounds, which were the most affected class of secondary metabolites. This might be explained by the modulation in amino acid metabolism, phenylpropanoids, and terpenes being more marked for black shading ( Li et al, 2020 ). Despite this, blue net provokes an accumulation of precursors of N-containing metabolites and the accumulation of some phenylpropanoids [dalnigrein 7- O -β- D -apiofuranosyl-(1–6)-β- D -glucopyranoside, amorphigenin, cyanidin 3- O -(6″- O -malonyl)-β-glucoside, 4-hydroxycoumarin] according to previous results.…”

“…However, the application of the blue spectrum in seedling cultivation has rarely been studied or documented in scientific manuscripts, and very little is known about the metabolic changes associated with planting exposition to the blue net. Considering the direct linkage between light and essential processes (not limited to photosynthesis) and its connection to the carbon and nitrogen fluxes ( Li et al, 2020 ), studying the metabolic processes underlying selective shading is crucial in understanding the profound impact of shading in crops. In this sense, the hypothesis-free comprehensive profiling provided by untargeted metabolomics may provide a holistic overview of the different biochemical processes triggered by selective shading, thus providing valuable insights into the metabolic reprogramming induced in crops.…”

Phenotypic Markers Reflecting the Status of Overstressed Tea Plants Subjected to Repeated Shade Cultivation

“…At the bud-opening stage in the first crop season, the starch content of branches decreased in response to repeated shading but was unchanged in ML and TR (Figure 8). According to Li et al (2020), who performed metabolic profiling, C metabolism in leaves is inhibited by long-term shading. Therefore, carbon metabolism in overstressed tea plants may be inhibited throughout the entire plant, not just the branches, even if no effect on final starch content is observed.…”