Dataset Information

Putative genes in alkaloid biosynthesis identified in Dendrobium officinale by correlating the contents of major bioactive metabolites with genes expression between Protocorm-like bodies and leaves.

ABSTRACT:

Background

Dendrobium officinale, an endangered Chinese herb, possesses extensive therapeutic effects and contains bioactive ingredients such as major polysaccharides, alkaloids, and minimal flavonoids. We first obtained the protocorm-like bodies (PLBs) of this plant through tissue culture in order to determine the distribution of the main secondary metabolites in each organelle and the PLBs. We then analyzed the correlation between gene expression level from comparative transcriptome sequencing and metabolite content in different organs to identify putative genes encoding enzymes involved in the biosynthesis of polysaccharides, alkaloids, and flavonoids.

Results

We used seeds as explants for protocorm induction and PLB propagation of D. officinale. The optimal medium formula for PLB propagation was 1/2 MS + α-NAA 0.5 mg·L^- 1 + 6-BA 1.0 mg·L^- 1 + 2, 4-D 1.5-2.0 mg·L^- 1 + potato juice 100 g·L^- 1. Stems, PLBs and leaves of D. officinale had the highest content of polysaccharides, alkaloids and flavonoids, respectively. Naringenin was only produced in stem; however, PLBs with high alkaloid content can replace other organs producing alkaloids. The hot water extraction method outperformed the ultrasound-assisted extraction method for extracting polysaccharides from D. officinale. A comparative transcriptome analysis of PLBs and leaves of D. officinale revealed differential expression of genes encoding enzymes involved in polysaccharide, alkaloid and flavonoid biosynthetic pathways. Putative genes encoding enzymes involved in these biosynthetic pathways were identified. Notably, we identified genes encoding the alkaloid biosynthesis enzymes strictosidine β-D-Glucosidase, geissoschizine synthase and vinorine synthase in D. officinale.

Conclusions

The identification of candidate genes encoding enzymes involved in metabolite biosynthesis will help to explore and protect this endangered species and facilitate further analysis of the molecular mechanism of secondary metabolite biosynthesis in D. officinale.

SUBMITTER: Wang Z

PROVIDER: S-EPMC8323239 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background: Dendrobium officinale, an endangered Chinese herb, has extensive therapeutic effects and contains bioactive ingredients including a large number of polysaccharides and alkaloids, and minimal flavonoids. Firstly, this study attempts to obtain the protocorm-like bodies of this plant through tissue culture to produce the main secondary metabolites whose distribution in each organelle and protocorm like bodies is analyzed. Then, analysis of the correlation between comparative transcriptome sequence and the metabolite content in different organs enables the discovery of putative genes encoding enzymes involved in the biosynthesis of polysaccharides and alkaloids, and flavonoids. Results: The optimum condition for protocorm-like bodies (PLBs) induction and propagation of D. officinale is established. For protocorm induction, we use the seed as the explant, and the optimum medium formula for PLBs propagation is 1/2 MS + α-NAA 0.5 mg·L-1 +6-BA 1.0 mg·L-1 + 2, 4-D 1.5-2.0 mg·L-1 + potato juice 100 g·L-1. The distribution of polysaccharides, alkaloids and flavonoids in D. officinale organs was clarified. Stems, PLBs and leaves have the highest content of polysaccharides, alkaloids and flavonoids, respectively. PLBs replace organs to produce alkaloids in D. officinale, and naringenin was only produced in stem. Hot water extraction (HWE) method was found outperforming the ultrasound-assisted extraction (UAE) method for polysaccharides from D. officinale. A comparative transcriptome analysis of the protocorm-like bodies and leaves of D. officinale showed genes encoding enzymes involved in polysaccharides, alkaloids and flavonoids biosynthetic pathway were differentially expressed. Putative genes encoding enzymes involved in polysaccharides, alkaloids and flavonoids synthetic pathway were identified. Notably, genes encoding enzymes of strictosidine beta-glucosidase, geissoschizine synthase and vinorine synthase in alkaloids biosynthesis of D. officinale are first reported. Conclusions: Our works, especially the identification of candidate genes encoding enzymes involved in metabolites biosynthesis will help to explore and protect the endangered genetic resources and will also facilitate further analysis of the molecular mechanism of secondary metabolites’ biosynthesis in D. officinale.