An Integrative Analysis of Metabolome and Transcriptome Reveals the Molecular Regulatory Mechanism of the Accumulation of Flavonoid Glycosides in Different Cyclocarya paliurus Ploidies

Abstract

Cyclocarya paliurus (Batal) Iljinskaja is mainly used for harvesting leaves as materials for tea production and ingredients for the food industry. As its most important component, the contents of its total or specific flavonoids are supposed to vary at different ploidy levels. In the present study, two ploidy levels of C. paliurus are used to study their metabolome and transcriptome profiles. Though the total content of the flavonoids in leaves that were collected in September (the main harvesting season) presented insignificant differences between the two ploidies, flavonoid glucuronides were significantly accumulated in the tetraploid C. paliurus. Several structural genes related to the biosynthesis of these flavonoid glucuronides were expressed differentially, including PAL, 4CL, CHS, and CpUGTs. A weighted gene co-expression network analysis (WGCNA) revealed that nine genes were highly correlated with the flavonoid glucuronide contents. Furthermore, 3 CpMYB39 and 3 CpUGT71 were highly associated with this accumulation of flavonoid glucuronides in tetraploid C. paliurus. These results can provide a new perspective on how different polyploid levels alter the quantitative and qualitative patterns of the secondary metabolite production in C. paliurus.

Technical Scheme for Cutting Seedlings of Cyclocarya paliurus under Intelligent Control of Environmental Factors

“…Nonetheless, once fully established, the tree exhibits remarkable drought tolerance, making it an ideal species for dry and arid climates as well [14]. In fact, research has shown that C. paliurus has developed specific mechanisms to cope with drought stress [15], including the ability to reduce water loss through its leaves and rapidly activate the synthesis of proline and alleviate the production of reactive oxygen species (ROS) [16,17]. This impressive ability to adapt to challenging environments makes C. paliurus an exciting species for both horticultural and ecological purposes.…”

“…Most cultivation starts with leaf and stem cuttings [23,24]. Furthermore, grafting techniques can be used to enhance the growth and yield of C. paliurus [17]. By grafting the resulting plant onto different rootstocks, growers can produce stronger, more disease-resistant plants with improved fruit production.…”