Integrated transcriptomic and metabolomic analysis reveals the molecular basis of tissue-specific accumulation of bioactive steroidal alkaloids in Fritillaria unibracteata

Multi-Omics on Traditional Medicinal Plant of the Genus Aconitum: Current Progress and Prospect

Aconitum stands out among the Ranunculaceae family for its notable use as an ornamental and medicinal plant. Diterpenoid alkaloids (DAs), the characteristic compounds of Aconitum, have been found to have effective analgesic and anti-inflammatory effects. Despite their medicinal potential, the toxicity of most DAs restricts the direct use of Aconitum in traditional medicine, necessitating complex processing before use. The use of high-throughput omics allows for the investigation of Aconitum plant genetics, gene regulation, metabolic pathways, and growth and development. We have collected comprehensive information on the omics studies of Aconitum medicinal plants, encompassing genomics, transcriptomics, metabolomics, proteomics, and microbiomics, from internationally recognized electronic scientific databases such as Web of Science, PubMed, and CNKI. In light of this, we identified research gaps and proposed potential areas and key objectives for Aconitum omics research, aiming to establish a framework for quality improvement, molecular breeding, and a deeper understanding of specialized metabolite production in Aconitum plants.

Long-term air pollution exposure and the blood metabolome: The rotterdam study

BACKGROUND

Air pollution is a well-established risk factor for several adverse health outcomes, but the specific molecular mechanisms, particularly those involving metabolic processes, remain incompletely understood.

OBJECTIVE

To evaluate associations between long-term air pollutant exposure and circulating plasma metabolites in two sub-cohorts of the population-based Rotterdam Study.

METHODS

We analyzed data from 1455 participants of sub-cohort I (mean age 76.9 years, 58% female, 2002-2004) and 1061 participants from sub-cohort III (mean age 62.6 years, 56% female, 2012-2014). Mean annual exposure to fine particulate matter (PM2.5), black carbon, nitrogen dioxide, and ozone (measured both annually and in warm seasons only) were estimated at residential addresses using land use regression models. Plasma metabolites were measured by Metabolon Inc., using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry. Cross-sectional associations between each air pollutant and 940 metabolites were determined using linear regression models. Benjamini-Hochberg false discovery rate (FDR) was utilized to control for multiple testing. Enrichment analysis was performed on statistically significant associated metabolites to identify significant metabolic pathways (p-value <0.05).

RESULTS

In sub-cohort I, PM2.5, black carbon, nitrogen dioxide, annual ozone and ozone in warm season were statistically significantly associated with, respectively, 63, 30, 20, 31, and 41 metabolites (FDR <0.05) mostly belonging to lipid and amino acid sub-classes, and unannotated metabolites. Sphinganine, X - 16576 and 2-pyrrolidinone displayed statistically significant associations across all five air pollutants. In sub-cohort III, black carbon, nitrogen dioxide and ozone in warm seasons were associated with a single unannotated metabolite (X - 24970), and annual ozone with two unannotated metabolites (X - 24970 and X - 24306). Enriched pathways identified in sub-cohort I included pyrimidine metabolism and steroid hormone biosynthesis.

CONCLUSIONS

Our study revealed associations of long-term air pollutant exposure with several metabolites and enrichment of two pathways, which are known to be involved in the adrenal and reproductive system and cell metabolism.

Metabolomic and transcriptomic analyses reveals candidate genes and pathways involved in secondary metabolism in Bergenia purpurascens

Bergenia purpurascens is an important medicinal, edible and ornamental plant. The lack of omics information hinders the study of its metabolic pathways and related genes. In order to investigate candidate genes and pathways involved in secondary metabolism in B. purpurascens, roots, stems and leaves of B. purpurascens were subjected to metabolomic and transcriptomic analyses in this study. A total of 351 differentially accumulated secondary metabolites were identified. We identified 120 candidate genes involved in phenylpropanoid and flavonoid biosynthesis pathway, from which 29 key candidate genes were obtained by WGCNA. Five UDP-Glycosyltransferases and four O-methyltransferases were suggested to be the candidate enzymes involved in synthetic pathway from gallic acid to bergenin by correlation analysis between transcriptional and metabolic levels and phylogenetic analysis. This study provides data resources and new insights for further studies on the biosynthesis of major active components in B. purpurascens.

Isolation and Identification of Alkaloid Genes from the Biomass of Fritillaria taipaiensis P.Y. Li

BACKGROUND/OBJECTIVES

Fritillaria taipaiensis P.Y. Li is a valuable traditional Chinese medicinal herb that utilizes bulbs as medicine, which contain multiple alkaloids. Biomass, as a sustainable resource, has promising applications in energy, environmental, and biomedical fields. Recently, the biosynthesis and regulatory mechanisms of the main biomass components of biomass have become a prominent research topic.

METHODS

In this article, we explored the differences in the heterosteroidal alkaloid components of F. taipaiensis biomass using liquid chromatography-mass spectrometry and high-throughput transcriptome sequencing.

RESULTS

The experimental results demonstrated significant differences in the eight types of heterosteroidal alkaloid components among the biomass of F. taipaiensis, including peimisine, imperialine, peimine, peiminine, ebeinone, ebeiedine, ebeiedinone, and forticine. Transcriptomic analysis revealed substantial significant differences in gene expression patterns in the various samples. Three catalytic enzyme-coding genes, 3-hydroxy-3-methylglutaryl coenzyme A synthase (HMGS), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), and terpene synthase (TPS), were speculated to contribute to the regulation of the differential accumulation of alkaloid synthesis in F. taipaiensis bulbs. A strong positive correlation was observed between the transcriptional level of the TPS gene and the alkaloid content of F. taipaiensis biomass, suggesting that TPS may be a key gene in the biosynthesis pathway of alkaloids. This finding can be used for subsequent gene function verification and molecular regulatory network analysis.

CONCLUSIONS

This work provides fundamental data and novel insights for the subsequent research on alkaloid biosynthesis in F. taipaiensis.

Genome-wide identification of AP2/ERF gene family in Coptis Chinensis Franch reveals its role in tissue-specific accumulation of benzylisoquinoline alkaloids

BACKGROUND

The Plant-specific AP2/ERF gene family encodes proteins involved in various biological and physiological processes. Although the genome of Coptis chinensis Franch, a plant producing benzylisoquinoline alkaloids (BIAs), has been sequenced at the chromosome level, studies on the AP2/ERF gene family in C. chinensis are lacking. Thus, a genome-wide identification of AP2/ERF gene family in C. chinensis was conducted to explore its role in BIAs biosynthesis.

RESULTS

A total of 96 CcAP2/ERF genes were identified and categorized into five subfamilies, including 43 ERFs, 32 DREBs, 17 AP2s, 3 RAVs, and 1 Soloist, based on their structural domains. These CcAP2/ERF genes were unevenly distributed across nine chromosomes. Analysis of gene duplication events identified 17 CcAP2/ERF gene pairs in the genome, with 7 involved in tandem duplication events and 10 involved in segmental duplicate events, indicating that both types of duplications contributed to the expansion of the AP2/ERF gene family. The Ka/Ks ratio analysis suggested that the CcAP2/ERF gene family underwent strong purifying selection. Two phytohormones, methyl jasmonate and abscisic acid, were identified as potential key inducers of BIAs biosynthesis due to the cis-acting element prediction. Analysis of the spatial transcriptomic data revealed that 28 differentially expressed AP2/ERF genes had the highest or relatively higher expression levels in the rhizome, 17 of which positively correlated with the tissue-specific accumulation of BIAs. Further real-time PCR verification and protein-protein interaction analysis indicated that DREB1B might be one of the central regulators in a highly complex BIAs biosynthesis network.

CONCLUSION

These findings provide significant insight into the function of AP2/ERF genes in C. chinensis, particularly in the regulatory network of BIAs biosynthesis in C. chinensis. This study also identifies candidate genes for metabolic engineering to increase BIAs content in C. chinensis.

Botanical characterization, phytochemistry, biosynthesis, pharmacology clinical application, and breeding techniques of the Chinese herbal medicine Fritillaria unibracteata

Fritillaria unibracteata (FRU) belongs to the genus Fritillaria of the Liliaceae family. It is one of the original plants of the Chinese medicinal material "Chuanbeimu" and also a biological resource featured in the Tibetan Plateau of China. The dried bulbs of FRU are used in traditional Chinese medicine. The chemical constituents of FRU that have been isolated and identified include alkaloids, sterols, organic acids and their esters, nucleosides and volatile oils. FRU has antitussive, expectorant, anti-asthmatic, anti-inflammatory, antibacterial, acute lung injury-reducing, antifibrosis, antitumor, and other pharmacological effects. This valuable plant has an extremely high market demand, and over the years, due to over-exploitation, FRU has now been listed as a key species that is endangered and scarcely cultivated in China as a traditional Chinese medicinal herb. However, research on FRU is rare, and its effective components, resource control, and mechanisms of action need further study. This review systematically discusses the herbal characteristics, resource distribution, chemical composition, biosynthesis, pharmacological effects, clinical application, and breeding techniques of FRU, hoping to provide a reference for further research and the use of FRU.

Bioinformatic Analysis of Codon Usage Bias of HSP20 Genes in Four Cruciferous Species

Heat shock protein 20 (HSP20) serves as a chaperone and plays roles in numerous biological processes, but the codon usage bias (CUB) of its genes has remained unexplored. This study identified 140 HSP20 genes from four cruciferous species, Arabidopsis thaliana, Brassica napus, Brassica rapa, and Camelina sativa, that were identified from the Ensembl plants database, and we subsequently investigated their CUB. As a result, the base composition analysis revealed that the overall GC content of HSP20 genes was below 50%. The overall GC content significantly correlated with the constituents at three codon positions, implying that both mutation pressure and natural selection might contribute to the CUB. The relatively high ENc values suggested that the CUB of the HSP20 genes in four cruciferous species was relatively weak. Subsequently, ENc exhibited a negative correlation with gene expression levels. Analyses, including ENc-plot analysis, neutral analysis, and PR2 bias, revealed that natural selection mainly shaped the CUB patterns of HSP20 genes in these species. In addition, a total of 12 optimal codons (ΔRSCU > 0.08 and RSCU > 1) were identified across the four species. A neighbor-joining phylogenetic analysis based on coding sequences (CDS) showed that the 140 HSP20 genes were strictly and distinctly clustered into 12 subfamilies. Principal component analysis and cluster analysis based on relative synonymous codon usage (RSCU) values supported the fact that the CUB pattern was consistent with the genetic relationship at the gene level and (or) species levels. These results will not only enrich the HSP20 gene resource but also advance our understanding of the CUB of HSP20 genes, which may underlie the theoretical basis for exploration of their genetic and evolutionary pattern.

Biomod2 modeling for predicting the potential ecological distribution of three Fritillaria species under climate change

The Fritillaria species ranked as a well-known traditional medicine in China and has become rare due to excessive harvesting. To find reasonable strategy for conservation and cultivation, identification of new ecological distribution of Fritillaria species together with prediction of those responses to climate change are necessary. In terms of current occurrence records and bioclimatic variables, the suitable habitats for Fritillaria delavayi, Fritillaria taipaiensis, and Fritillaria wabuensis were predicted. In comparison with Maxent and GARP, Biomod2 obtained the best AUC, KAPPA and TSS values of larger than 0.926 and was chosen to construct model. Temperature seasonality was indicated to put the greatest influence on Fritillaria taipaiensis and Fritillaria wabuensis, while isothermality was of most importance for Fritillaria delavayi. The current suitable areas for three Fritillaria species were distributed in south-west China, accounting for approximately 17.72%, 23.06% and 20.60% of China's total area, respectively. During 2021-2100 period, the suitable habitats of F. delavayi and F. wabuensis reached the maximum under SSP585 scenario, while that of F. taipaiensis reached the maximum under SSP126 scenario. The high niche overlap among three Fritillaria species showed correlation with the chemical composition (P ≤ 0.05), while no correlation was observed between niche overlap and DNA barcodes, indicating that spatial distribution had a major influence on chemical composition in the Fritillaria species. Finally, the acquisition of species-specific habitats would contribute to decrease in habitat competition, and future conservation and cultivation of Fritillaria species.

Differential roles of Cassia tora 1-deoxy-D-xylulose-5-phosphate synthase and 1-deoxy-D-xylulose-5-phosphate reductoisomerase in trade-off between plant growth and drought tolerance

Due to global climate change, drought is emerging as a major threat to plant growth and agricultural productivity. Abscisic acid (ABA) has been implicated in plant drought tolerance, however, its retarding effects on plant growth cannot be ignored. The reactions catalyzed by 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) proteins are critical steps within the isoprenoid biosynthesis in plants. Here, five DXS (CtDXS1-5) and two DXR (CtDXR1-2) genes were identified from Cassia tora genome. Based on multiple assays including the phylogeny, cis-acting element, expression pattern, and subcellular localization, CtDXS1 and CtDXR1 genes might be potential candidates controlling the isoprenoid biosynthesis. Intriguingly, CtDXS1 transgenic plants resulted in drought tolerance but retardant growth, while CtDXR1 transgenic plants exhibited both enhanced drought tolerance and increased growth. By comparison of β-carotene, chlorophyll, abscisic acid (ABA) and gibberellin 3 (GA3) contents in wild-type and transgenic plants, the absolute contents and (or) altered GA3/ABA levels were suggested to be responsible for the balance between drought tolerance and plant growth. The transcriptome of CtDXR1 transgenic plants suggested that the transcript levels of key genes, such as DXS, 9-cis-epoxycarotenoid dioxygenases (NCED), ent-kaurene synthase (KS) and etc, involved with chlorophyll, β-carotene, ABA and GA3 biosynthesis were induced and their contents increased accordingly. Collectively, the trade-off effect induced by CtDXR1 was associated with redesigning architecture in phytohormone homeostasis and thus was highlighted for future breeding purposes.