Metabolite Profiling and Transcriptome Analysis Explains Difference in Accumulation of Bioactive Constituents in Licorice (Glycyrrhiza uralensis) Under Salt Stress

Abstract

Salinity stress significantly affects the contents of bioactive constituents in licorice Glycyrrhiza uralensis. To elucidate the molecular mechanism underlying the difference in the accumulation of these constituents under sodium chloride (NaCl, salt) stress, licorice seedlings were treated with NaCl and then subjected to an integrated transcriptomic and metabolite profiling analysis. The transcriptomic analysis results identified 3,664 differentially expressed genes (DEGs) including transcription factor family MYB and basic helix-loop-helix (bHLH). Most DEGs were involved in flavonoid and terpenoid biosynthesis pathways. In addition, 121 compounds including a triterpenoid and five classes of flavonoids (isoflavone, flavone, flavanone, isoflavan, and chalcone) were identified, and their relative levels were compared between the stressed and control groups using data from the ultrafast liquid chromatography (UFLC)–triple quadrupole–time of flight–tandem mass spectrometry (TOF–MS/MS) analysis. Putative biosynthesis networks of the flavonoids and triterpenoids were created and combined with structural DEGs such as phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase [4CL], cinnamate 4-hydroxylase [C4H], chalcone synthase [CHS], chalcone-flavanone isomerase [CHI], and flavonoid-3′,5′ hydroxylase (F3′,5′H) for flavonoids, and CYP88D6 and CYP72A154 for glycyrrhizin biosynthesis. Notably, significant upregulation of UDP-glycosyltransferase genes (UGT) in salt-stressed licorice indicated that postmodification of glycosyltransferase may participate in downstream biosynthesis of flavonoid glycosides and triterpenoid saponins. Accordingly, the expression trend of the DEGs is positively correlated with the accumulation of glycosides. Our study findings indicate that key DEGs and crucial UGT genes co-regulate flavonoid and saponin biosynthesis in licorice under salt stress.

Integrated Analysis of Widely Targeted Metabolomics and Transcriptomics Reveals the Effects of Transcription Factor NOR-like1 on Alkaloids, Phenolic Acids, and Flavonoids in Tomato at Different Ripening Stages

“…The genes associated with flavonoid biosynthesis are mainly classified into structural and regulatory genes [41]for instance, CHS, FLS, F3H, F3 H, C4H, etc. C4H plays an important role in flavonoid biosynthesis [42][43][44]. Correlation analysis showed that C4H at all three ripening stages positively regulated flavonoids including luteolin, hesperetin, homoeriodictyol, phloretin, butin, aromadendrin, naringenin chalcone, and pinobanksin.…”

Glycyrrhiza uralensis Nodules: Histological and Ultrastructural Organization and Tubulin Cytoskeleton Dynamics

“…This plant is actively being studied due to its economic importance; the analysis of its transcriptome [8,9], and the assembly and annotation of its draft genome [10], and complete chloroplast [11] and mitochondrial [12] genomes, have been carried out to date. Recently, the effects of different stressors on transcriptome activity in G. uralensis plants have also been analyzed [13,14].…”

Metabolite Profiling and Transcriptome Analysis Explain the Difference in Accumulation of Bioactive Constituents in Taxilli Herba from Two Hosts

“…Transcriptome studies are increasingly expanding from model plants to non-model plants, and plant gene sequence analysis has greatly expanded plant databases. It has been shown that differences in the expression of genes based on metabolic pathways can be used to investigate the regulation of secondary metabolite synthesis and accumulation at the molecular level during plant development [45]. At present, the whole chloroplast genome of TH has been sequenced, but because TH is not a model plant the study of transcriptome data of TH is limited.…”