Exploring the genes involved in biosynthesis of dihydroquercetin and dihydromyricetin in Ampelopsis grossedentata

Abstract

Dihydroquercetin (DHQ), an extremely low content compound (less than 3%) in plants, is an important component of dietary supplements and used as functional food for its antioxidant activity. Moreover, as downstream metabolites of DHQ, an extremely high content of dihydromyricetin (DHM) is up to 38.5% in Ampelopsis grossedentata. However, the mechanisms involved in the biosynthesis and regulation from DHQ to DHM in A. grossedentata remain unclear. In this study, a comparative transcriptome analysis of A. grossedentata containing extreme amounts of DHM was performed on the Illumina HiSeq 2000 sequencing platform. A total of 167,415,597 high-quality clean reads were obtained and assembled into 100,584 unigenes having an N50 value of 1489. Among these contigs, 57,016 (56.68%) were successfully annotated in seven public protein databases. From the differentially expressed gene (DEG) analysis, 926 DEGs were identified between the B group (low DHM: 210.31 mg/g) and D group (high DHM: 359.12 mg/g) libraries, including 446 up-regulated genes and 480 down-regulated genes (B vs. D). Flavonoids (DHQ, DHM)-related DEGs of ten structural enzyme genes, three myeloblastosis transcription factors (MYB TFs), one basic helix–loop–helix (bHLH) TF, and one WD40 domain-containing protein were obtained. The enzyme genes comprised three PALs, two CLs, two CHSs, one F3’H, one F3’5’H (directly converts DHQ to DHM), and one ANS. The expression profiles of randomly selected genes were consistent with the RNA-seq results. Our findings thus provide comprehensive gene expression resources for revealing the molecular mechanism from DHQ to DHM in A. grossedentata. Importantly, this work will spur further genetic studies about A. grossedentata and may eventually lead to genetic improvements of the DHQ content in this plant.

Identification of Hydroxylation Enzymes and the Metabolic Analysis of Dihydromyricetin Synthesis in Ampelopsis grossedentata

“…However, the highest content detected in this study was only about 23% of the dry weight. This might be because DHM was different in different strains [ 22 ] and growth environments. Interestingly, the tendrils also contained a high DHM content.…”

“…Without considering the correctness of sequence length, they annotated 18 for Ag F3H, 8 for Ag F3′5′H, and 1 for Ag F3′H. Yu et al [ 22 ] elucidated candidate genes involved in the biosynthesis and regulation of flavonoids (DHM and DHQ) through comparative transcriptome analysis. In their study, they found that the upregulation of Ag F3′5′H expression increased the DHQ and DHM contents.…”

“…Li et al analyzed the transcriptome of A. grossedentata for the first time and predicted some genes related to flavonoid synthesis based on the Kyoto encyclopedia of genes and genomes (KEGG) and other databases [ 21 ]. Yu et al [ 22 ] also predicted several candidate genes involved in the DHM biosynthesis pathway. Li and Yu performed solid preliminary studies; however, all key genes were predicted instead of verified in vitro or in vivo.…”

Comparative Transcriptome Analysis Unveils the Molecular Mechanism Underlying Sepal Colour Changes under Acidic pH Substratum in Hydrangea macrophylla

“…The biosynthesis pathway of flavonoids is dependent on F3H , F3′H , and F3′5′H . They catalyse the hydroxylation of flavonoids required for anthocyanin production, such as dihydrokaempferol, dihydromyricetin, and dihydroquercetin [ 42 , 43 ]. F3H catalyses the conversion of naringenin to dihydroflavones.…”

Application of High-Throughput Sequencing on the Chinese Herbal Medicine for the Data-Mining of the Bioactive Compounds

“…Dihydroquercetin (DHQ) is a pharmacologically active, which can be converted to dihydromyricetin (DHM). Yu Z. et al (2021) used HPLC to detect the DHM content in Ampelopsis grossedentata from different geographical locations and divided into two groups: B group (low DHM) and D group (high DHM). Then, Illumina HiSeq 2000 sequencing platform was performed to sequence the transcriptome of A. grossedentata from B and D groups and annotated 57,016 unigenes in D group using seven public protein databases.…”