Impaired terpenoid backbone biosynthesis reduces saponin accumulation in Panax notoginseng under Cd stress

Integrated metabolomic and transcriptomic analysis of triterpenoid accumulation in the roots of Codonopsis pilosula var. modesta (Nannf.) L.T.Shen at different altitudes

INTRODUCTION

Codonopsis Radix is a beneficial traditional Chinese medicine, and triterpenoid are the major bioactive constituents. Codonopsis pilosula var. modesta (Nannf.) L.T.Shen (CPM) is a precious variety of Codonopsis Radix, which is distributed at high mountain areas. The environment plays an important role in the synthesis and metabolism of active ingredients in medicinal plants, but there is no report elaborating on the effect of altitude on terpenoid metabolites accumulation in CPM.

OBJECTIVES

This study aims to analyse the effects of altitude on triterpenoid biosynthetic pathways and secondary metabolite accumulation in CPM.

MATERIAL AND METHODS

The untargeted metabolomics based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and 10 triterpenoids based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) method were analysed at the low-altitude (1480 m) and high-altitude (2300 m) CPM fresh roots. The transcriptome based on high-throughput sequencing technology were combined to analyse the different altitude CPM triterpenoid biosynthetic pathways.

RESULTS

A total of 17,351 differentially expressed genes (DEGs) and 55 differentially accumulated metabolites (DAMs) were detected from the different altitude CPM, and there are significant differences in the content of the 10 triterpenoids. The results of transcriptome study showed that CPM could significantly up-regulate the gene expression levels of seven key enzymes in the triterpenoid biosynthetic pathway.

CONCLUSIONS

The CPM at high altitude is more likely to accumulate triterpenes than those at low altitude, which was related to the up-regulation of the gene expression levels of seven key enzymes. These results expand our understanding of how altitude affects plant metabolite biosynthesis.

Weighted single-step GWAS identified candidate genes associated with carcass traits in a Chinese yellow-feathered chicken population

Carcass traits in broiler chickens are complex traits that are influenced by multiple genes. To gain deeper insights into the genetic mechanisms underlying carcass traits, here we conducted a weighted single-step genome-wide association study (wssGWAS) in a population of Chinese yellow-feathered chicken. The objective was to identify genomic regions and candidate genes associated with carcass weight (CW), eviscerated weight with giblets (EWG), eviscerated weight (EW), breast muscle weight (BMW), drumstick weight (DW), abdominal fat weight (AFW), abdominal fat percentage (AFP), gizzard weight (GW), and intestine length (IL). A total of 1,338 broiler chickens with phenotypic and pedigree information were included in this study. Of these, 435 chickens were genotyped using a 600K single nucleotide polymorphism chip for association analysis. The results indicate that the most significant regions for 9 traits explained 2.38% to 5.09% of the phenotypic variation, from which the region of 194.53 to 194.63Mb on chromosome 1 with the gene RELT and FAM168A identified on it was significantly associated with CW, EWG, EW, BMW, and DW. Meanwhile, the 5 traits have a strong genetic correlation, indicating that the region and the genes can be used for further research. In addition, some candidate genes associated with skeletal muscle development, fat deposition regulation, intestinal repair, and protection were identified. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses suggested that the genes are involved in processes such as vascular development (CD34, FGF7, FGFR3, ITGB1BP1, SEMA5A, LOXL2), bone formation (FGFR3, MATN1, MEF2D, DHRS3, SKI, STC1, HOXB1, HOXB3, TIPARP), and anatomical size regulation (ADD2, AKT1, CFTR, EDN3, FLII, HCLS1, ITGB1BP1, SEMA5A, SHC1, ULK1, DSTN, GSK3B, BORCS8, GRIP2). In conclusion, the integration of phenotype, genotype, and pedigree information without creating pseudo-phenotype will facilitate the genetic improvement of carcass traits in chickens, providing valuable insights into the genetic architecture and potential candidate genes underlying carcass traits, enriching our understanding and contributing to the breeding of high-quality broiler chickens.

Physiological and metabolomic analyses reveal that Fe3O4 nanoparticles ameliorate cadmium and arsenic toxicity in Panax notoginseng

Heavy metal(loid)-contaminated available arable land seriously affects crop development and growth. Engineered nanomaterials have great potential in mitigating toxic metal(loid) stress in plants. However, there are few details of nanoparticles (NPs) involved in Panax notoginseng response to cadmium (Cd) and arsenic (As). Herein, integrating physiological and metabolomic analyses, we investigated the effects of Fe3O4 NPs on plant growth and Cd/As responses in P. notoginseng. Cd/As treatment caused severe growth inhibition. However, foliar application of Fe3O4 NPs increased beneficial elements in the roots and/or leaves, decreased Cd/As content by 10.38% and 20.41% in the roots, reduced membrane damage and regulated antioxidant enzyme activity, thereby alleviating Cd/As-induced growth inhibition, as indicated by increased shoot fresh weight (FW), the rootlet length and root FW by 40.14%, 15.74%, and 46.70% under Cd stress and promoted the shoot FW by 27.00% under As toxicity. Metabolomic analysis showed that 227 and 295 differentially accumulated metabolites (DAMs) were identified, and their accumulation patterns were classified into 8 and 6 clusters in the roots and leaves, respectively. Fe3O4 NPs altered metabolites significantly involved in key pathways, including amino sugar and nucleotide sugar metabolism, flavonoid biosynthesis and phenylalanine metabolism, thus mediating the trade-off between plant growth and defense under stress. Interestingly, Fe3O4 NPs recovered more Cd/As-induced DAMs to normal levels, further supporting that Fe3O4 NPs positively affected seedling growth under metal(loid)s stress. In addition, Fe3O4 NPs altered terpenoids when the seedlings were subjected to Cd/As stress, thus affecting their potential medicinal value. This study provides insights into using nanoparticles to improve potential active ingredients of medicinal plants in metal(loid)-contaminated areas.

Analysis of the heavy metal contents' effect on steroidal saponins and the anti-breast cancer activity of Paris polyphylla var. yunnanensis

Background: P. polyphylla var. yunnanensis, as a near-threatened and ethnic medicine in China, used to be a key ingredient in traditional Chinese medicine in treatment of traumatic injuries, sore throat, snakebites, and convulsions for thousands of years. However, there were no reports on the inverse relationship between the contents of heavy metals and saponins and its anti-breast cancer pharmacological activity in P. polyphylla var. yunnanensis. Methods: The present study aimed to reveal the characteristics of heavy metal contents and saponins and its anti-breast cancer pharmacological activity and their interrelationships in P. polyphylla var. yunnanensis from different production areas. The contents of heavy metal and steroidal saponins in P. polyphylla var. yunnanensis were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and the high-performance liquid chromatography technique, respectively. The Pearson correlation was used to study the correlation between saponins and heavy metals. 4T1 mouse mammary tumor cells were selected and cultivated for antitumor studies in vitro. Cell Counting Kit-8 (CCK-8) assay, Hoechst staining, and flow cytometry analysis were used for the examination of the proliferation and apoptosis of 4T1 tumor cells. Mouse breast cancer 4T1 cells were subcutaneously injected into BALB/c mice to construct a tumor model to explore the in vivo inhibitory effect on breast cancer. TUNEL assay and immunohistochemistry were used for the examination of the effect of P. polyphylla var. yunnanensis from different origins on cancer cell proliferation and apoptosis induction in 4T1 tumor mice. Results: Heavy metal contents were highly correlated with the content of steroidal saponins. The overall content of 10 metals in the three producing origins was of the order C3 >C2 >C1. The total content of eight steroidal saponins in the extracts of P. polyphylla var. yunnanensis from three different origins was C1 >C2 >C3. The Pearson correlation study showed that in all of the heavy metals, the contents of Cd and Ba were positively correlated with the main steroidal saponins in P. polyphylla var. yunnanensis, while Al, Cr, Cu, Fe, Zn, As, Hg, and Pb showed a negative correlation. In vitro experiments showed that the extracts of P. polyphylla var. yunnanensis from three origins could inhibit the proliferation and induce cell apoptosis of 4T1 cells in a concentration- and time-dependent manner, especially in the C1 origin. In vivo experiments showed that the extract of P. polyphylla var. yunnanensis from the three origins could inhibit the growth of tumors and induce the apoptosis of tumor cells. In the three origins, C1 origin had the lowest total heavy metal level but the highest total steroidal saponin level. Therefore, it showed a better effect in reducing the expression of the human epidermal growth factor receptor 2 (HER2) and Kiel 67 (Ki67) and increasing the expression of p53 in tumor tissues compared to the other origins. In conclusion, in the three origins, C1 origin exhibits antitumor pharmacological effects in vivo and in vitro which are better than those in the other origins. Conclusion: In this study, we found that with the increase of the heavy metal content, the content of steroid saponins and anti-breast cancer activity decreased. The results showed that the high content of the total heavy metals may not be conducive to the accumulation of steroidal saponins in P. polyphylla var. yunnanensis and lead to the low anti-breast cancer activity. The results of this study suggest that the content of heavy metals should be controlled in the artificial cultivation process of P. polyphylla var. yunnanensis.

Combined Metabolome and Transcriptome Analysis of Creamy Yellow and Purple Colored Panax notoginseng Roots

Panax notoginseng (Burk.) F.H. Chen is a species of the Araliaceae family that inhabits southwestern China, Burma, and Nepal. It is cultivated on a commercial scale in Yunnan province, China, owing to its significance in traditional Chinese medicine. Panax notoginseng roots are usually yellow-white (HS); however, purple roots (ZS) have also been reported. The majority of P. notoginseng research has concentrated on the identification and production of natural chemicals in HS; however, there is little to no information about the composition of ZS. Using UPLC-MS/MS, we investigated the global metabolome profile of both ZS- and HS-type roots and discovered 834 metabolites from 11 chemical groups. There were 123 differentially accumulated metabolites (DAM) in the HS and ZS roots, which were classified as lipids and lipid-like molecules, polyketides, organoheterocyclic chemicals, and organooxygen compounds. We investigated the associated compounds in the DAMs because of the importance of anthocyanins in color and saponins and ginsenosides in health benefits. In general, we discovered that pigment compounds such as petunidin 3-glucoside, delphinidin 3-glucoside, and peonidin-3-O-beta-galactoside were more abundant in ZS. The saponin (eight compounds) and ginsenoside (26 compounds) content of the two varieties of roots differed as well. Transcriptome sequencing revealed that flavonoid and anthocyanin production genes were more abundant in ZS than in HS. Similarly, we found differences in gene expression in genes involved in terpenoid production and related pathways. Overall, these findings suggest that the purple roots of P. notoginseng contain varying amounts of ginsenosides and anthocyanins compared to roots with a creamy yellow color.

Ultraviolet-B and Heavy Metal-Induced Regulation of Secondary Metabolites in Medicinal Plants: A Review

Despite a rich history and economic importance, the potential of medicinal plants has not been fully explored under different abiotic stress conditions. Penetration of UV-B radiation and contamination of heavy metals are two important environmental stress for plants with remarkable influence on the defense-related and pharmaceutically important secondary metabolites of medicinal plants. UV-B and heavy metal contamination may become a critical issue that either positively or negatively affects the quality and quantity of secondary metabolites. Such effects may result from changes in the expression level of genes that encode the corresponding enzymes or the inactivation and/or stimulation of specific enzymes involved in the different biosynthetic pathways of the secondary metabolites. Therefore, a comprehensive study of the impact of UV-B and heavy metals individually and in combination on the biosynthesis and accumulation of secondary metabolites in medicinal plants is discussed in the present review.

Effects of lime and oxalic acid on antioxidant enzymes and active components of Panax notoginseng under cadmium stress

Cadmium (Cd) pollution poses potential safety risks for Panax notoginseng cultivation, a medicinal plant in Yunnan. Under exogenous Cd stress, field experiments were conducted to understand the effects of lime (0, 750, 2250 and 3750 kg hm⁻²) applied and oxalic acid (0, 0.1 and 0.2 mol L⁻¹) leaves sprayed on Cd accumulation, antioxidant system and medicinal components of P. notoginseng. The results showed that Lime and foliar spray of oxalic acid were able to elevate Ca²⁺ and alleviate Cd²⁺ toxicity in P. notoginseng under Cd stress. The addition of lime and oxalic acid increased the activities of antioxidant enzymes and alters osmoregulator metabolism. The most significant increase in CAT activities increased by 2.77 folds. And the highest increase of SOD activities was 1.78 folds under the application of oxalic acid. While MDA content decreased by 58.38%. There were very significant correlation with soluble sugar, free amino acid, proline and soluble protein. Lime and oxalic acid were able to increase calcium ions (Ca²⁺), decrease Cd content and improve the stress resistance of P. notoginseng, while increasing the production of total saponins and flavonoids. Cd content were the lowest, 68.57% lower than controls, and met the standard value (Cd ≤ 0.5 mg kg⁻¹, GB/T 19086-2008). The proportion of SPN was 7.73%, which reached the highest level of all treatments, the flavonoids content increased significantly by 21.74%, which reached the medicinal standard value and optimal yield.

Overexpression of PnMYB2 from Panax notoginseng induces cellulose and lignin biosynthesis during cell wall formation

Panax notoginseng PnMYB2 is a transcriptional activator of primary and secondary cell wall formation by promoting the PCW-specific gene CesA3 and key lignin biosynthetic gene CCoAOMT1, respectively. R2R3-MYB transcription factors play important roles in regulation secondary cell wall (SCW) formation. However, there are few reports on the functions of MYB transcription factors which involved in both primary cell wall (PCW) and SCW formation. Here, we isolated an R2R3-MYB transcription factor, PnMYB2, from Panax notoginseng roots which are widely used in Chinese traditional medicines and contain abundant cellulose and lignin. The expression pattern of PnMYB2 was similar to the accumulation pattern of cellulose and lignin contents in different organs. PnMYB2 localized in the nucleus and may function as a transcriptional activator. Overexpression of PnMYB2 in Arabidopsis thaliana enhanced cellulose and lignin biosynthesis, and remarkably increased thickness of PCW and SCW in the stem of transgenic plants compared with wild-type plants. The expression levels of genes associated with PCW-specific cellulose synthase (CesA) genes and key SCW-specific lignin biosynthetic genes were significantly increased in PnMYB2-overexpressing plants compared to the wild type plants. Furthermore, yeast one-hybrid, dual-luciferase reporter assays and electrophoretic mobility shift assays (EMSA) results verified that PnMYB2 could bind and activate the promoters of AtCesA3 and PnCesA3, which are the PCW-specific cellulose biosynthetic genes, and AtCCoAOMT1 and PnCCoAOMT1, which are the key lignin biosynthetic genes. These results demonstrated the central role of PnMYB2 in PCW-specific cellulose formation and SCW-specific lignin biosynthesis.

Potassium enhances cadmium resistance ability of Panax notoginseng by brassinolide signaling pathway-regulated cell wall pectin metabolism

The mechanism of how potassium (K) attenuates cadmium (Cd)-induced demethylation and anabolism of cell wall (CW) pectin through the brassinolide (BR) signaling pathway was verified in Panax notoginseng (Burk.). The P. notoginseng pectin methylesterase gene (PnPME1) was cloned and functionally verified in tobacco. Pectin and BR metabolism, Cd content and the pectin methylation degree (PMD) were detected in response to K, 2,4-epibrassinolide (EBL), and brassinazole treatments of P. notoginseng and tobacco under Cd stress. Activity of the main root pectin methylesterase enzyme (PME) was promoted by 22.29% under the EBL treatment, and Cd content increased by 29.03% under Cd stress. Potassium reduced PME activity and Cd content in main root pectin by 61.03% and 50.73%, respectively, under the EBL and Cd co-treatment. Potassium inhibited the promoting effects of Cd stress on the expression of PnPME1 by 57.04%. Potassium also inhibited expression of BR synthesis genes PnDET2, PnROT3, PnCYP90A1, and PnBR6OX1 by 65.61%, 52.02%, 47.36%, and 55.16%, respectively, and reduced the accumulation of Cd. The PnPME1 was located in the CW. The activity of transgenic tobacco root PME was higher than that of the wild-type, while the PMD was significantly lower. The regulatory effects of K and EBL on tobacco root pectin metabolism were consistent with those in P. notoginseng. In conclusion, K downregulated the expression of BR synthesis genes in P. notoginseng roots under Cd stress and reduced the production of BRs, which inhibited PnPME1 expression. The reduction in PME activity increased the PMD, which reduced the accumulation of Cd.

Melatonin increases leaf disease resistance and saponin biosynthesis in Panax notogiseng

Panax notoginseng (Bruk.) FH Chen is a valuable traditional herb in China, with saponins being the main medicinal components in its roots. However, leaf diseases are a major factor limiting growth and production of P. notoginseng. Melatonin is a ubiquitous signaling molecule associated with abiotic stress resistance. In this study, we investigated the role of melatonin in leaf disease resistance of P. notoginseng in field conditions. Additionally, saponin concentrations were analyzed to evaluate the suitability of melatonin use in agricultural practice. Our results showed that exogenous application of melatonin promoted the endogenous phytomelatonin accumulation via upregulation of genes involved in its biosynthesis. The application of 10 μM melatonin decreased the incidence of leaf diseases (gray mold, round spot, and black spot) by about 40% compared with the solvent control, which might have been due to the increased expression of genes associated with immunity and disease resistance. Furthermore, concentrations of saponins and expression of their biosynthesis-related genes were significantly increased by melatonin. Taken together, the data presented here suggested that melatonin could be used in agricultural management of P. notoginseng because it increased leaf disease resistance and biosynthesis of saponins.

Exploration of the Role of Serine Proteinase Inhibitor A3 in Alcohol Dependence Using Gene Expression Omnibus Database

Background: Alcohol dependence is an overall health-related challenge; however, the specific mechanisms underlying alcohol dependence remain unclear. Serine proteinase inhibitor A3 (SERPINA3) plays crucial roles in multiple human diseases; however, its role in alcohol dependence clinical practice has not been confirmed. Methods: We screened Gene Expression Omnibus (GEO) expression profiles, and identified differentially expressed genes (DEGs). Protein-protein interaction (PPI) networks were generated using STRING and Cytoscape, and the key clustering module was identified using the MCODE plugin. SERPINA3-based target microRNA prediction was performed using online databases. Functional enrichment analysis was performed. Fifty-eight patients with alcohol dependence and 20 healthy controls were recruited. Clinical variables were collected and follow-up was conducted for 8 months for relapse. Results: SERPINA3 was identified as a DEG. ELANE and miR-137 were identified after PPI analysis. The enriched functions and pathways included acute inflammatory response, response to stress, immune response, and terpenoid backbone biosynthesis. SERPINA3 concentrations were significantly elevated in the alcohol dependence group than in healthy controls (P < 0.001). According to the median value of SERPINA3 expression level in alcohol dependence group, patients were divided into high SERPINA3 (≥2677.33 pg/ml, n = 29) and low SERPINA3 groups (<2677.33 pg/ml, n = 29). Binary logistic analysis indicated that IL-6 was statistically significant (P = 0.015) Kaplan-Meier survival analysis did not indicate any difference in event-free survival between patients with low and high SERPINA3 levels (P = 0.489) after 8 months of follow-up. Receiver characteristic curve analysis revealed that SERPINA3 had an area under the curve of 0.921 (P < 0.0001), with a sensitivity and specificity of 93.1 and 80.0%, respectively. Cox regression analysis revealed that aspartate transaminase level was a negative predictor of relapse (β = 0.003; hazard ratio = 1.003; P = 0.03). Conclusions: SERPINA3 level was remarkably elevated in patients with alcohol dependence than healthy controls, indicating that SERPINA3 is correlated with alcohol dependence. However, SERPINA3 may not be a potential predictive marker of relapse with patients in alcohol dependence.