Transcriptome and mebabolomic profiling: the effect of LED light quality on morphological traits, and phenylpropanoid-derived compounds accumulation in Sarcandra glabra seedlings

Abstract

Background Sarcandra glabra is an evergreen and traditional Chinese herb, having medicinal significance as anti-oxidant, anti-bacterial, anti-inflammatory, and anti-tumor. Recently, China has initiated to establish cultivation of this plant in greenhouse under artificial light-emitting diodes (LED). However, little is known regarding the effects of the different LED lights on plant growth, accumulation pattern of secondary metabolites, and the molecular mechanism of Sarcandra glabra. Results Compared to white light (WL), the red light (RL) increased the height and decreased the stem diameter and leaf area, while blue light (BL) suppressed the height and leaf area. According to our transcriptome profiling, some differentially expressed genes (DEGs) were enriched in the phenylpropanoid biosynthesis. We identified 46 unigenes encoding for almost all known enzymes involved in phenylpropanoid biosynthesis, while the expression level of RNA-seq and qPCR were largely consistent. Meanwhile, we found 53 unigenes encoding R2R3-MYB proteins and 53 unigenes encoding bHLH proteins that several of them were related to flavonoids biosynthesis. Based on metabolomic profiling, a total of 454 metabolites were detected and the distribution of chemicals varied significantly. While flavonoids, phenolic acids, and tannins were mainly located in leaves; Organic acids, lignans and coumarins, and terpenoids were much more abundant in WG (root tissue under WL). Meanwhile, the yields of most flavonoids from BY (leaf tissue under BL) and the synthesis of primarily targeted compounds was lower than in WY (leaf tissue under WL) and RY (leaf tissue under RL). Instead, the leaves grown under RL exhibited a greater production of bioactive phytochemicals such as esculetin, fraxetin, esculin, and scopoletin. Conclusion These results provide further insight into the molecular mechanism of metabolites accumulation patterns in S. glabra under different light conditions, enabling the development of optimum breeding conditions for this plant.