Complete plastome sequence of Mallotus japonicus (Linn. f.) Müll. Arg. (Euphorbiaceae): a medicinal plant species endemic in East Asia

The complete plastome of Acalypha australis (Euphorbiaceae) and its phylogenetic analysis

Acalypha australis L. 1753 is a potherb popular among Asian populations and is a traditional herbal medicine. In the current study, the overall genetic diversity of A. australis still needs to be better. Here, we assembled and characterized the complete plastome of A. australis. The plastome is 168,885 bp in length with a large single-copy (LSC) of 94,576 bp, a small single-copy (SSC) of 19,715 bp, and two copies of inverted repeat region (IRs) of 27,297 bp each. The overall GC content is 34.9%. The plastome contains 127 genes, including 83 protein-coding genes, 36 tRNA genes, and eight rRNA genes. Phylogenomic analysis of the representative species of Euphorbiaceae showed that A. australis and A. hispida formed a monophyletic sister clade. The results of this study will support further research on the evolution and conservation of the Euphorbiaceae species; they will benefit pharmaceutical applications and ornamentation of the medicinal plant A. australis.

The mechanism leading to color differences between purple-red and green partridge tea leaves

BACKGROUND

Partridge tea (Mallotus oblongifolius) is used as an important beverage and medical plant in Hainan province of China. Although some information about the morphology, cytology, and genetics of partridge tea has been reported in the literature, knowledge about this plant is still very limited. The leaves are the most important part for every tea plant, with a major role in nutrition and other functions. The leaves of different cultivars of partridge tea are different in colors and functions. The molecular mechanism of color formation of partridge tea leaf is still unclear. We reveal the molecular mechanism of the color difference between purple-red and green partridge tea leaves through metabolome and transcriptome analysis.

RESULTS

We identified 665 compounds in the two partridge tea cultivars through metabolome analysis. Among these compounds, the content of 324 differed between the two cultivars. We also annotated 50 042 unigenes in the two cultivars by transcriptome analysis; 9665 unigenes were expressed differently between the two cultivars. Using an integrated analysis of the metabolome and transcriptome data, we found that the compounds and genes involved in anthocyanin biosynthesis were up-regulated in the purple-red leaves, compared with the green leaves.

CONCLUSION

Our results showed that the anthocyanin biosynthesis pathway genes were up-regulated, which resulted in the up-regulation of the anthocyanin, making the leaf color purple-red. Our study reveals the molecular mechanism of the color difference between purple-red and green partridge tea, and lays a foundation for the genetic breeding of partridge tea genetic and the utilization of its volatile components. © 2022 Society of Chemical Industry.

Gene-Metabolite Network Analysis Revealed Tissue-Specific Accumulation of Therapeutic Metabolites in Mallotus japonicus

Mallotus japonicus is a valuable traditional medicinal plant in East Asia for applications as a gastrointestinal drug. However, the molecular components involved in the biosynthesis of bioactive metabolites have not yet been explored, primarily due to a lack of omics resources. In this study, we established metabolome and transcriptome resources for M. japonicus to capture the diverse metabolite constituents and active transcripts involved in its biosynthesis and regulation. A combination of untargeted metabolite profiling with data-dependent metabolite fragmentation and metabolite annotation through manual curation and feature-based molecular networking established an overall metabospace of M. japonicus represented by 2129 metabolite features. M. japonicus de novo transcriptome assembly showed 96.9% transcriptome completeness, representing 226,250 active transcripts across seven tissues. We identified specialized metabolites biosynthesis in a tissue-specific manner, with a strong correlation between transcripts expression and metabolite accumulations in M. japonicus. The correlation- and network-based integration of metabolome and transcriptome datasets identified candidate genes involved in the biosynthesis of key specialized metabolites of M. japonicus. We further used phylogenetic analysis to identify 13 C-glycosyltransferases and 11 methyltransferases coding candidate genes involved in the biosynthesis of medicinally important bergenin. This study provides comprehensive, high-quality multi-omics resources to further investigate biological properties of specialized metabolites biosynthesis in M. japonicus.