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Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants

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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Plant Sciences".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 17161

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Special Issue Editor

Prof. Dr. Shanfa Lu

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Guest Editor

Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China
Interests: medicinal plant; bioactive compound; biosynthetic pathway; noncoding RNA; transcription factor; genome; transcriptome; metabolome
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Medicinal plants are an important resource for humans. However, compared with model systems and crops, the number of studies on medicinal plants has fallen far behind the amount of research on other topics. Recently, with the increase in demand for medicinal plants and the development and application of high-throughput technologies, the research field of medicinal plants has rapidly expanded. Significant progress has been made in genomics, epigenomics, transcriptomics and metabolomics of medicinal plants. Numerous studies have contributed to the biosynthetic pathway of secondary metabolites, genes encoding key enzymes of the pathway, and regulatory mechanisms of secondary metabolism. This enables the production of secondary metabolites through metabolic engineering and synthetic biology. Moreover, novel technologies and strategies are developing and applying to this research field. This open-access Special Issue of IJMS is devoted to publishing original research and review articles on medicinal plant studies, highlighting recent advances in the biosynthesis and regulatory mechanisms of secondary metabolites, particularly significant discoveries from intensive studies, and the development and application of novel technologies. This issue aims to provide an accessible collection of research that shares the latest innovative results from the research field of medicinal plants to aid further studies on secondary metabolism, medicinal plant improvement, and the production of functionally important secondary metabolites.

Topics of this Special Issue include, but are not limited to:

Genomics, epigenomics, transcriptomics and metabolomics of medicinal plants;
Biosynthetic pathway of secondary metabolites;
Key enzyme genes involved in the biosynthesis of secondary metabolites;
Epigenetic regulation of secondary metabolism: microRNA, long noncoding RNA, DNA methylation, RNA methylation, etc.;
Transcription factor and regulatory network in medicinal plants;
Metabolic engineering and synthetic biology of secondary metabolites;
Application of high-throughput sequencing technologies;
Databases associated with the biosynthesis and regulation of secondary metabolites;
Novel technologies and strategies for secondary metabolism studies.

Prof. Dr. Shanfa Lu
Guest Editor

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Keywords

biosynthetic pathway
epigenetic regulation
high-throughput sequencing
medicinal plant
metabolic engineering
omics
regulatory mechanism
secondary metabolite
synthetic biology
transcription factor

Related Special Issue

Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants 2.0 in International Journal of Molecular Sciences (1 article)

Published Papers (13 papers)

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Research

15 pages, 10118 KiB

Open AccessArticle

Overexpression of AtMYB2 Promotes Tolerance to Salt Stress and Accumulations of Tanshinones and Phenolic Acid in Salvia miltiorrhiza

by Tianyu Li, Shuangshuang Zhang, Yidan Li, Lipeng Zhang, Wenqin Song and Chengbin Chen

Int. J. Mol. Sci. 2024, 25(7), 4111; https://doi.org/10.3390/ijms25074111 - 08 Apr 2024

Viewed by 427

Abstract

Salvia miltiorrhiza is a prized traditional Chinese medicinal plant species. Its red storage roots are primarily used for the treatment of cardiovascular and cerebrovascular diseases. In this study, a transcription factor gene AtMYB2 was cloned and introduced into Salvia miltiorrhiza for ectopic expression. Overexpression of AtMYB2 enhanced salt stress resistance in S. miltiorrhiza, leading to a more resilient phenotype in transgenic plants exposed to high-salinity conditions. Physiological experiments have revealed that overexpression of AtMYB2 can decrease the accumulation of reactive oxygen species (ROS) during salt stress, boost the activity of antioxidant enzymes, and mitigate oxidative damage to cell membranes. In addition, overexpression of AtMYB2 promotes the synthesis of tanshinones and phenolic acids by upregulating the expression of biosynthetic pathway genes, resulting in increased levels of these secondary metabolites. In summary, our findings demonstrate that AtMYB2 not only enhances plant tolerance to salt stress, but also increases the accumulation of secondary metabolites in S. miltiorrhiza. Our study lays a solid foundation for uncovering the molecular mechanisms governed by AtMYB2 and holds significant implications for the molecular breeding of high-quality S. miltiorrhiza varieties. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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16 pages, 9579 KiB

Open AccessArticle

Metabolic Pathway Engineering Improves Dendrobine Production in Dendrobium catenatum

by Meili Zhao, Yanchang Zhao, Zhenyu Yang, Feng Ming, Jian Li, Demin Kong, Yu Wang, Peng Chen, Meina Wang and Zhicai Wang

Int. J. Mol. Sci. 2024, 25(1), 397; https://doi.org/10.3390/ijms25010397 - 28 Dec 2023

Viewed by 808

Abstract

The sesquiterpene alkaloid dendrobine, widely recognized as the main active compound and a quality control standard of medicinal orchids in the Chinese Pharmacopoeia, demonstrates diverse biological functions. In this study, we engineered Dendrobium catenatum as a chassis plant for the production of dendrobine through the screening and pyramiding of key biosynthesis genes. Initially, previously predicted upstream key genes in the methyl-D-erythritol 4-phosphate (MEP) pathway for dendrobine synthesis, including 4-(Cytidine 5′-Diphospho)-2-C-Methyl-d-Erythritol Kinase (CMK), 1-Deoxy-d-Xylulose 5-Phosphate Reductoisomerase (DXR), 2-C-Methyl-d-Erythritol 4-Phosphate Cytidylyltransferase (MCT), and Strictosidine Synthase 1 (STR1), and a few downstream post-modification genes, including Cytochrome P450 94C1 (CYP94C1), Branched-Chain-Amino-Acid Aminotransferase 2 (BCAT2), and Methyltransferase-like Protein 23 (METTL23), were chosen due to their deduced roles in enhancing dendrobine production. The seven genes (SG) were then stacked and transiently expressed in the leaves of D. catenatum, resulting in a dendrobine yield that was two-fold higher compared to that of the empty vector control (EV). Further, RNA-seq analysis identified Copper Methylamine Oxidase (CMEAO) as a strong candidate with predicted functions in the post-modification processes of alkaloid biosynthesis. Overexpression of CMEAO increased dendrobine content by two-fold. Additionally, co-expression analysis of the differentially expressed genes (DEGs) by weighted gene co-expression network analysis (WGCNA) retrieved one regulatory transcription factor gene MYB61. Overexpression of MYB61 increased dendrobine levels by more than two-fold in D. catenatum. In short, this work provides an efficient strategy and prospective candidates for the genetic engineering of D. catenatum to produce dendrobine, thereby improving its medicinal value. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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13 pages, 4335 KiB

Open AccessArticle

Technology Invention and Mechanism Analysis of Rapid Rooting of Taxus × media Rehder Branches Induced by Agrobacterium rhizogenes

by Ying Wang, Xiumei Luo, Haotian Su, Ge Guan, Shuang Liu and Maozhi Ren

Int. J. Mol. Sci. 2024, 25(1), 375; https://doi.org/10.3390/ijms25010375 - 27 Dec 2023

Viewed by 586

Abstract

Taxus, a vital source of the anticancer drug paclitaxel, grapples with a pronounced supply–demand gap. Current efforts to alleviate the paclitaxel shortage involve expanding Taxus cultivation through cutting propagation. However, traditional cutting propagation of Taxus is difficult to root and time-consuming. Obtaining the roots with high paclitaxel content will cause tree death and resource destruction, which is not conducive to the development of the Taxus industry. To address this, establishing rapid and efficient stem rooting systems emerges as a key solution for Taxus propagation, facilitating direct and continuous root utilization. In this study, Agrobacterium rhizogenes were induced in the 1–3-year-old branches of Taxus × media Rehder, which has the highest paclitaxel content. The research delves into the rooting efficiency induced by different A. rhizogenes strains, with MSU440 and C58 exhibiting superior effects. Transcriptome and metabolome analyses revealed A. rhizogenes’ impact on hormone signal transduction, amino acid metabolism, zeatin synthesis, and secondary metabolite synthesis pathways in roots. LC-MS-targeted quantitative detection showed no significant difference in paclitaxel and baccatin III content between naturally formed and induced roots. These findings underpin the theoretical framework for T. media rapid propagation, contributing to the sustainable advancement of the Taxus industry. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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15 pages, 4163 KiB

Open AccessArticle

Comparison of the Metabolomics of Different Dendrobium Species by UPLC-QTOF-MS

by Tingting Zhang, Xinxin Yang, Fengzhong Wang, Pengfei Liu, Mengzhou Xie, Cong Lu, Jiameng Liu, Jing Sun and Bei Fan

Int. J. Mol. Sci. 2023, 24(24), 17148; https://doi.org/10.3390/ijms242417148 - 05 Dec 2023

Viewed by 832

Abstract

Dendrobium Sw. (family Orchidaceae) is a renowned edible and medicinal plant in China. Although widely cultivated and used, less research has been conducted on differential Dendrobium species. In this study, stems from seven distinct Dendrobium species were subjected to UPLC-QTOF-MS/MS analysis. A total of 242 metabolites were annotated, and multivariate statistical analysis was employed to explore the variance in the extracted metabolites across the various groups. The analysis demonstrated that D. nobile displays conspicuous differences from other species of Dendrobium. Specifically, D. nobile stands out from the remaining six taxa of Dendrobium based on 170 distinct metabolites, mainly terpene and flavonoid components, associated with cysteine and methionine metabolism, flavonoid biosynthesis, and galactose metabolism. It is believed that the variations between D. nobile and other Dendrobium species are mainly attributed to three metabolite synthesis pathways. By comparing the chemical composition of seven species of Dendrobium, this study identified the qualitative components of each species. D. nobile was found to differ significantly from other species, with higher levels of terpenoids, flavonoids, and other compounds that are for the cardiovascular field. By comparing the chemical composition of seven species of Dendrobium, these qualitative components have relevance for establishing quality standards for Dendrobium. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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17 pages, 2190 KiB

Open AccessArticle

Evaluation of Reference Genes for Normalizing RT-qPCR and Analysis of the Expression Patterns of WRKY1 Transcription Factor and Rhynchophylline Biosynthesis-Related Genes in Uncaria rhynchophylla

by Detian Mu, Yingying Shao, Jialong He, Lina Zhu, Deyou Qiu, Iain W. Wilson, Yao Zhang, Limei Pan, Yu Zhou, Ying Lu and Qi Tang

Int. J. Mol. Sci. 2023, 24(22), 16330; https://doi.org/10.3390/ijms242216330 - 15 Nov 2023

Cited by 1 | Viewed by 708

Abstract

Uncaria rhynchophylla (Miq.) Miq. ex Havil, a traditional medicinal herb, is enriched with several pharmacologically active terpenoid indole alkaloids (TIAs). At present, no method has been reported that can comprehensively select and evaluate the appropriate reference genes for gene expression analysis, especially the transcription factors and key enzyme genes involved in the biosynthesis pathway of TIAs in U. rhynchophylla. Reverse transcription quantitative PCR (RT-qPCR) is currently the most common method for detecting gene expression levels due to its high sensitivity, specificity, reproducibility, and ease of use. However, this methodology is dependent on selecting an optimal reference gene to accurately normalize the RT-qPCR results. Ten candidate reference genes, which are homologues of genes used in other plant species and are common reference genes, were used to evaluate the expression stability under three stress-related experimental treatments (methyl jasmonate, ethylene, and low temperature) using multiple stability analysis methodologies. The results showed that, among the candidate reference genes, S-adenosylmethionine decarboxylase (SAM) exhibited a higher expression stability under the experimental conditions tested. Using SAM as a reference gene, the expression profiles of 14 genes for key TIA enzymes and a WRKY1 transcription factor were examined under three experimental stress treatments that affect the accumulation of TIAs in U. rhynchophylla. The expression pattern of WRKY1 was similar to that of tryptophan decarboxylase (TDC) under ETH treatment. This research is the first to report the stability of reference genes in U. rhynchophylla and provides an important foundation for future gene expression analyses in U. rhynchophylla. The RT-qPCR results indicate that the expression of WRKY1 is similar to that of TDC under ETH treatment. It may coordinate the expression of TDC, providing a possible method to enhance alkaloid production in the future through synthetic biology. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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22 pages, 10575 KiB

Open AccessArticle

Reference Genes Screening and Gene Expression Patterns Analysis Involved in Gelsenicine Biosynthesis under Different Hormone Treatments in Gelsemium elegans

by Yao Zhang, Detian Mu, Liya Wang, Xujun Wang, Iain W. Wilson, Wenqiang Chen, Jinghan Wang, Zhaoying Liu, Deyou Qiu and Qi Tang

Int. J. Mol. Sci. 2023, 24(21), 15973; https://doi.org/10.3390/ijms242115973 - 04 Nov 2023

Cited by 2 | Viewed by 780

Abstract

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is an accurate method for quantifying gene expression levels. Choosing appropriate reference genes to normalize the data is essential for reducing errors. Gelsemium elegans is a highly poisonous but important medicinal plant used for analgesic and anti-swelling purposes. Gelsenicine is one of the vital active ingredients, and its biosynthesis pathway remains to be determined. In this study, G. elegans leaf tissue with and without the application of one of four hormones (SA, MeJA, ETH, and ABA) known to affect gelsenicine synthesis, was analyzed using ten candidate reference genes. The gene stability was evaluated using GeNorm, NormFinder, BestKeeper, ∆CT, and RefFinder. The results showed that the optimal stable reference genes varied among the different treatments and that at least two reference genes were required for accurate quantification. The expression patterns of 15 genes related to the gelsenicine upstream biosynthesis pathway was determined by RT-qPCR using the relevant reference genes identified. Three genes 8-HGO, LAMT, and STR, were found to have a strong correlation with the amount of gelsenicine measured in the different samples. This research is the first study to examine the reference genes of G. elegans under different hormone treatments and will be useful for future molecular analyses of this medically important plant species. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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14 pages, 3086 KiB

Open AccessArticle

Synthesis of Crocin I and Crocin II by Multigene Stacking in Nicotiana benthamiana

by Lei Xie, Zuliang Luo, Xunli Jia, Changming Mo, Xiyang Huang, Yaran Suo, Shengrong Cui, Yimei Zang, Jingjing Liao and Xiaojun Ma

Int. J. Mol. Sci. 2023, 24(18), 14139; https://doi.org/10.3390/ijms241814139 - 15 Sep 2023

Cited by 2 | Viewed by 1344

Abstract

Crocins are a group of highly valuable water-soluble carotenoids that are reported to have many pharmacological activities, such as anticancer properties, and the potential for treating neurodegenerative diseases including Alzheimer’s disease. Crocins are mainly biosynthesized in the stigmas of food–medicine herbs Crocus sativus L. and Gardenia jasminoides fruits. The distribution is narrow in nature and deficient in resources, which are scarce and expensive. Recently, the synthesis of metabolites in the heterologous host has opened up the potential for large-scale and sustainable production of crocins, especially for the main active compounds crocin I and crocin II. In this study, GjCCD4a, GjALDH2C3, GjUGT74F8, and GjUGT94E13 from G. jasminoides fruits were expressed in Nicotiana benthamiana. The highest total content of crocins in T1 generation tobacco can reach 78,362 ng/g FW (fresh weight) and the dry weight is expected to reach 1,058,945 ng/g DW (dry weight). Surprisingly, the primary effective constituents crocin I and crocin II can account for 99% of the total crocins in transgenic plants. The strategy mentioned here provides an alternative platform for the scale-up production of crocin I and crocin II in tobacco. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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15 pages, 3372 KiB

Open AccessArticle

Characterization of Volatile Organic Compounds in Five Celery (Apium graveolens L.) Cultivars with Different Petiole Colors by HS-SPME-GC-MS

by Yue Sun, Mengyao Li, Xiaoyan Li, Jiageng Du, Weilong Li, Yuanxiu Lin, Yunting Zhang, Yan Wang, Wen He, Qing Chen, Yong Zhang, Xiaorong Wang, Ya Luo, Aisheng Xiong and Haoru Tang

Int. J. Mol. Sci. 2023, 24(17), 13343; https://doi.org/10.3390/ijms241713343 - 28 Aug 2023

Cited by 1 | Viewed by 1020

Abstract

Celery (Apium graveolens L.) is an important vegetable crop cultivated worldwide for its medicinal properties and distinctive flavor. Volatile organic compound (VOC) analysis is a valuable tool for the identification and classification of species. Currently, less research has been conducted on aroma compounds in different celery varieties and colors. In this study, five different colored celery were quantitatively analyzed for VOCs using HS-SPME, GC-MS determination, and stoichiometry methods. The result revealed that γ-terpinene, d-limonene, 2-hexenal,-(E)-, and β-myrcene contributed primarily to the celery aroma. The composition of compounds in celery exhibited a correlation not only with the color of the variety, with green celery displaying a higher concentration compared with other varieties, but also with the specific organ, whereby the content and distribution of volatile compounds were primarily influenced by the leaf rather than the petiole. Seven key genes influencing terpenoid synthesis were screened to detect expression levels. Most of the genes exhibited higher expression in leaves than petioles. In addition, some genes, particularly AgDXS and AgIDI, have higher expression levels in celery than other genes, thereby influencing the regulation of terpenoid synthesis through the MEP and MVA pathways, such as hydrocarbon monoterpenes. This study identified the characteristics of flavor compounds and key aroma components in different colored celery varieties and explored key genes involved in the regulation of terpenoid synthesis, laying a theoretical foundation for understanding flavor chemistry and improving its quality. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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19 pages, 4059 KiB

Open AccessArticle

Biosynthesis of α-Bisabolol by Farnesyl Diphosphate Synthase and α-Bisabolol Synthase and Their Related Transcription Factors in Matricaria recutita L.

by Yuling Tai, Honggang Wang, Ping Yao, Jiameng Sun, Chunxiao Guo, Yifan Jin, Lu Yang, Youhui Chen, Feng Shi, Luyao Yu, Shuangshuang Li and Yi Yuan

Int. J. Mol. Sci. 2023, 24(2), 1730; https://doi.org/10.3390/ijms24021730 - 15 Jan 2023

Cited by 2 | Viewed by 2408

Abstract

The essential oil of German chamomile (Matricaria recutita L.) is widely used in food, cosmetics, and the pharmaceutical industry. α-Bisabolol is the main active substance in German chamomile. Farnesyl diphosphate synthase (FPS) and α-bisabolol synthase (BBS) are key enzymes related to the α-bisabolol biosynthesis pathway. However, little is known about the α-bisabolol biosynthesis pathway in German chamomile, especially the transcription factors (TFs) related to the regulation of α-bisabolol synthesis. In this study, we identified MrFPS and MrBBS and investigated their functions by prokaryotic expression and expression in hairy root cells of German chamomile. The results suggest that MrFPS is the key enzyme in the production of sesquiterpenoids, and MrBBS catalyzes the reaction that produces α-bisabolol. Subcellular localization analysis showed that both MrFPS and MrBBS proteins were located in the cytosol. The expression levels of both MrFPS and MrBBS were highest in the extension period of ray florets. Furthermore, we cloned and analyzed the promoters of MrFPS and MrBBS. A large number of cis-acting elements related to light responsiveness, hormone response elements, and cis-regulatory elements that serve as putative binding sites for specific TFs in response to various biotic and abiotic stresses were identified. We identified and studied TFs related to MrFPS and MrBBS, including WRKY, AP2, and MYB. Our findings reveal the biosynthesis and regulation of α-bisabolol in German chamomile and provide novel insights for the production of α-bisabolol using synthetic biology methods. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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14 pages, 5021 KiB

Open AccessArticle

A Novel R2R3-MYB Transcription Factor SbMYB12 Positively Regulates Baicalin Biosynthesis in Scutellaria baicalensis Georgi

by Wentao Wang, Suying Hu, Jing Yang, Caijuan Zhang, Tong Zhang, Donghao Wang, Xiaoyan Cao and Zhezhi Wang

Int. J. Mol. Sci. 2022, 23(24), 15452; https://doi.org/10.3390/ijms232415452 - 07 Dec 2022

Cited by 8 | Viewed by 1311

Abstract

Scutellaria baicalensis Georgi is an annual herb from the Scutellaria genus that has been extensively used as a traditional medicine for over 2000 years in China. Baicalin and other flavonoids have been identified as the principal bioactive ingredients. The biosynthetic pathway of baicalin in S. baicalensis has been elucidated; however, the specific functions of R2R3-MYB TF, which regulates baicalin synthesis, has not been well characterized in S. baicalensis to date. Here, a S20 R2R3-MYB TF (SbMYB12), which encodes 263 amino acids with a length of 792 bp, was expressed in all tested tissues (mainly in leaves) and responded to exogenous hormone methyl jasmonate (MeJA) treatment. The overexpression of SbMYB12 significantly promoted the accumulation of flavonoids such as baicalin and wogonoside in S. baicalensis hairy roots. Furthermore, biochemical experiments revealed that SbMYB12 is a nuclear-localized transcription activator that binds to the SbCCL7-4, SbCHI-2, and SbF6H-1 promoters to activate their expression. These results illustrate that SbMYB12 positively regulates the generation of baicalin and wogonoside. In summary, this work revealed a novel S20 R2R3-MYB regulator and enhances our understanding of the transcriptional and regulatory mechanisms of baicalin biosynthesis, as well as sheds new light on metabolic engineering in S. baicalensis. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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15 pages, 3769 KiB

Open AccessArticle

Transcription Factor SmSPL2 Inhibits the Accumulation of Salvianolic Acid B and Influences Root Architecture

by Xiangzeng Wang, Yao Cao, Jiaxin Yang, Tong Zhang, Qianqian Yang, Yanhua Zhang, Donghao Wang and Xiaoyan Cao

Int. J. Mol. Sci. 2022, 23(21), 13549; https://doi.org/10.3390/ijms232113549 - 04 Nov 2022

Cited by 2 | Viewed by 1174

Abstract

The SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) transcription factor play vital roles in plant growth and development. Although 15 SPL family genes have been recognized in the model medical plant Salvia miltiorrhiza Bunge, most of them have not been functionally characterized to date. Here, we performed a careful characterization of SmSPL2, which was expressed in almost all tissues of S. miltiorrhiza and had the highest transcriptional level in the calyx. Meanwhile, SmSPL2 has strong transcriptional activation activity and resides in the nucleus. We obtained overexpression lines of SmSPL2 and rSmSPL2 (miR156-resistant SmSPL2). Morphological changes in roots, including longer length, fewer adventitious roots, decreased lateral root density, and increased fresh weight, were observed in all of these transgenic lines. Two rSmSPL2-overexpressed lines were subjected to transcriptome analysis. Overexpression of rSmSPL2 changed root architectures by inhibiting biosynthesis and signal transduction of auxin, while triggering that of cytokinin. The salvianolic acid B (SalB) concentration was significantly decreased in rSmSPL2-overexpressed lines. Further analysis revealed that SmSPL2 binds directly to the promoters of Sm4CL9, SmTAT1, and SmPAL1 and inhibits their expression. In conclusion, SmSPL2 is a potential gene that efficiently manipulate both root architecture and SalB concentration in S. miltiorrhiza. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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18 pages, 4844 KiB

Open AccessArticle

Integrating Metabolomics and Transcriptomics to Unveil Atisine Biosynthesis in Aconitum gymnandrum Maxim

by Lingli Chen, Mei Tian, Baolong Jin, Biwei Yin, Tong Chen, Juan Guo, Jinfu Tang, Guanghong Cui and Luqi Huang

Int. J. Mol. Sci. 2022, 23(21), 13463; https://doi.org/10.3390/ijms232113463 - 03 Nov 2022

Cited by 2 | Viewed by 1724

Abstract

Diterpene alkaloids (DAs) are characteristic compounds in Aconitum, which are classified into four skeletal types: C₁₈, C₁₉, C₂₀, and bisditerpenoid alkaloids. C₂₀-DAs are thought to be the precursor of the other types. Their biosynthetic pathway, however, is largely unclear. Herein, we combine metabolomics and transcriptomics to unveil the methyl jasmonate (MJ) inducible biosynthesis of DAs in the sterile seedling of A. gymnandrum, the only species in the Subgenus Gymnaconitum (Stapf) Rapaics. Target metabolomics based on root and aerial portions identified 51 C₁₉-DAs and 15 C₂₀-DAs, with 40 inducible compounds. The highest content of C₂₀-DA atisine was selected for further network analysis. PacBio Isoform sequencing integrated with RNA sequencing not only provided the full-length transcriptome but also their response to induction, revealing 1994 genes that exhibited up-regulated expression. Further, 38 genes involved in terpenoid biosynthesis were identified, including 7 diterpene synthases. In addition to the expected function of the four diterpene synthases, AgCPS5 was identified to be a new ent-8,13-CPP synthase in Aconitum and could also combine with AgKSL1 to form the C₂₀-DAs precursor ent-atiserene. Combined with multiple network analyses, six CYP450 and seven 2-ODD genes predicted to be involved in the biosynthesis of atisine were also identified. This study not only sheds light on diterpene synthase evolution in Aconitum but also provides a rich dataset of full-length transcriptomes, systemic metabolomes, and gene expression profiles, setting the groundwork for further investigation of the C₂₀-DAs biosynthesis pathway. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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18 pages, 2698 KiB

Open AccessArticle

Plant Metabolic Engineering by Multigene Stacking: Synthesis of Diverse Mogrosides

by Jingjing Liao, Tingyao Liu, Lei Xie, Changming Mo, Xiyang Huang, Shengrong Cui, Xunli Jia, Fusheng Lan, Zuliang Luo and Xiaojun Ma

Int. J. Mol. Sci. 2022, 23(18), 10422; https://doi.org/10.3390/ijms231810422 - 09 Sep 2022

Cited by 6 | Viewed by 2373

Abstract

Mogrosides are a group of health-promoting natural products that extracted from Siraitia grosvenorii fruit (Luo-han-guo or monk fruit), which exhibited a promising practical application in natural sweeteners and pharmaceutical development. However, the production of mogrosides is inadequate to meet the need worldwide, and uneconomical synthetic chemistry methods are not generally recommended for structural complexity. To address this issue, an in-fusion based gene stacking strategy (IGS) for multigene stacking has been developed to assemble 6 mogrosides synthase genes in pCAMBIA1300. Metabolic engineering of Nicotiana benthamiana and Arabidopsis thaliana to produce mogrosides from 2,3-oxidosqualene was carried out. Moreover, a validated HPLC-MS/MS method was used for the quantitative analysis of mogrosides in transgenic plants. Herein, engineered Arabidopsis thaliana produced siamenoside I ranging from 29.65 to 1036.96 ng/g FW, and the content of mogroside III at 202.75 ng/g FW, respectively. The production of mogroside III was from 148.30 to 252.73 ng/g FW, and mogroside II-E with concentration between 339.27 and 5663.55 ng/g FW in the engineered tobacco, respectively. This study provides information potentially applicable to develop a powerful and green toolkit for the production of mogrosides. Full article

(This article belongs to the Special Issue Biosynthesis and Regulatory Mechanism of Secondary Metabolites in Medicinal Plants)

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