Yield Of Metabolites Research Articles

The role of methyl jasmonate in enhancing biomass yields and bioactive metabolites in Stauroneis sp. (Bacillariophyceae) revealed by proteome and biochemical profiling

The diatom Stauroneis sp. was previously identified as a promising source of fucoxanthin and omega-3 oils. Methyl jasmonate (MJ) supplementation is known to enhance metabolite yields in this species without impacting on growth or photosynthesis. Therefore, a label-free proteomics approach was undertaken to further evaluate the functional role of MJ on the diatom's physiology. Of the twenty cultivation regimes were screened, Uf/2 medium with green+white LED's induced the greatest metabolic response when exposed to 10 μM MJ treatment. These conditions significantly enhanced the pigment and total cellular lipids contents. The increase in fucoxanthin correlating with a 20% increase in Trolox reducing equivalent in the total antioxidant assay, indicating a non-enzymatic antioxidant role of fucoxanthin to mitigate the detrimental effects of a redox imbalance within chloroplasts. The proteomics identified 197 proteins up-regulated 48 h after MJ exposure including cell signalling cascades, photosynthetic processes, carbohydrate metabolism, lipid biosynthesis and chloroplast biogenesis. MJ strengthened the dark reactions of photosynthesis to support growth and metabolite fluxes. The MJ-induced ER stress protein triggered lipid body production, facilitating metabolite turnover and trafficking between cellular organelles. Plastid terminal oxidase and glutamate 1-semialdehyde 2,1-aminomutase may act as MJ-induced ROS responsive regulatory switch to support chloroplast biosynthesis. Significance statementPhytohormones represents a promising tool to enhance the high-value metabolite yields in plants and algae, however little is known of the role of methyl jasmonate in diatoms at a molecular level. A shotgun proteomics approach was undertaken to determine the influence of MJ on the diatom's cellular physiology in the marine diatom Stauroneis sp., revealing a signal transduction cascade leading to increased lipid and pigment content and identified promising targets for genetic engineering.

Isolation, optimized extraction, and ultra-high performance liquid chromatography with photodiode array method for quantitative analysis of chiratol in Swertia paniculata.

The global natural product-based industry is growing fast with the introduction of new phytochemicals and herbal extract products from different geographical regions. Swertia paniculata is a well-known plant with medicinal properties; however, the quality control for its major phytochemical constituents from the Himalayan geographical region is nevertheless reported. Therefore, the first objective of this investigation was to characterize and optimize the extraction process while the second objective was to validate a quantitative analytical method for chiratol from S. paniculata herbal extract. The chiratol was characterized with spectral analysis. The optimum extraction condition for the highest yield of metabolite was realized in chloroform as a solvent system under ultrasonication. The ultra-high performance liquid chromatography coupled with photodiode array detection method for analytical quantification was validated for specificity, linearity, limits of detection, limits of quantification, precision, repeatability, recovery, and robustness using Eclipse Plus C18 column (100mm × 4.6mm × 3.5μm id). The gradient elution of water/acetonitrile as mobile phase was used at a flow rate of 0.5ml/min. The recovery percentage was very satisfactory with values within specification. The robustness parameters showed no substantial influence of evaluated parameters by the Youden test. The developed method was ascertained to be appropriate for the proposed purpose.

Yield and Chemical Composition of Raw Material from Meadow Arnica (Arnica chamissonis Less.) Depending on Soil Conditions and Nitrogen Fertilization

Considering the global tendency towards using valuable secondary metabolites of plant origin, there is a need to optimize the cultivation of herbal plants, e.g., the meadow arnica (A. chamissonis Less.). The inflorescences of this species (Arnicae anthodium) have a similar chemical composition and pharmacological activity to that in the mountain arnica (Arnica montana L.), and can be cultivated more easily than the mountain arnica. Therefore this study assesses soil and fertilization effects on the flower head yield and concentrations of active substances (sesquiterpene lactones, flavonoids, and essential oil) with great importance for application in the pharmaceutical and cosmetic industries. A field experiment was carried out during 2017–2019 on two types of soil (sandy and loamy soils) differing in the pH values, organic matter content, and the P, K, and Mg levels. Five levels of nitrogen fertilization were applied in both soil variants: 0, 30, 60, 90, and 120 kg N∙ha−1. The study showed that both the soil type and the nitrogen fertilization had a positive impact on the raw material yield and the content and yield of the main active substances. The cultivation of arnica in the loamy soil was more favorable—it provided a higher flower head yield, higher levels of sesquiterpene lactones, flavonoids, and essential oils, and consequently, a higher yield of these metabolites. High flower head yields were achieved at doses of 60 and 90 kg N∙ha−1. The content of sesquiterpene lactones and essential oils increased in the consecutive study years along with the increase in nitrogen doses. The highest content of flavonoids was detected in flower heads obtained from three-year-old plants fertilized with 60 kg N∙ha−1. High yields of sesquiterpene lactones and essential oils were obtained at doses of 90–120 kg N∙ha−1, whereas the fertilization with 60–90 N∙ha−1 ensured a high yield of flavonoids. The yields of sesquiterpene lactones and essential oil did not depend on their concentration but correlated with the increase in the yield of flower heads of plants cultivated in both sandy and loamy soil variants. In turn, the yield of flavonoids was influenced by both their concentration and the flower head yield. The flower head yield, the content of sesquiterpene lactones, flavonoids, and essential oils, and the yields of metabolites presented in this study indicate favorable climatic conditions for the cultivation of A. chamissonis in Central and Eastern Poland. This proves that a wide range of pharmacologically active substances can be produced in this region of Europe.

Variation in the Methylation of Caffeoylquinic Acids and Urinary Excretion of 3'-methoxycinnamic acid-4'-Sulfate After Apple Consumption by Volunteers.

It has been reported that the phenolic metabolite 3'-methoxycinnamic acid-4'-sulfate generated from 5-O-caffeoylquinic acid may have potential benefits in human health. However, the variation in 3'- and 4'-methylation of 3',4'-dihydroxycinnamic acid and its impact on the yield of this sulfate metabolite is unclear and has been poorly studied. To address this aim, the excreted 3'-methoxy and 4'-methoxy metabolites in urine samples (24-h) are determined in 14 volunteers after an acute intake of 80g of red-fleshed apple (RFA) or white-fleshed apple (WFA). These methoxy metabolites are also determined in the same volunteers in a second acute intake after a 6-week sustained consumption of the same products. Seven 3'-methoxy and seven 4'-methoxy metabolites are determined, i.e., the free cinnamic and corresponding phenylpropanoic acid, plus their sulfate, glucuronide, and glycine conjugates. In only six volunteers, five females and one male, is 4'-methylation preferred over 3'-methylation, but it is observed that an individual's 3'- : 4'-methylation ratio can change over time, and that the yield of 3'-methoxycinnamic acid-4'-sulfate is extremely variable, ranging from undetectable to 71% of the total C6 -C3 metabolites excreted, and any benefit accruing from this metabolite will not necessarily be available to all consumers.

Analysis of Environmental Variables and Carbon Input on Soil Microbiome, Metabolome and Disease Control Efficacy in Strawberry Attributable to Anaerobic Soil Disinfestation.

Charcoal rot and Fusarium wilt, caused by Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae, respectively, are major soil-borne diseases of strawberry that have caused significant crop losses in California. Anaerobic soil disinfestation has been studied as an industry-level option to replace soil fumigants to manage these serious diseases. Studies were conducted to discern whether Gramineae carbon input type, incubation temperature, or incubation duration influences the efficacy of this disease control tactic. In experiments conducted using ‘low rate’ amendment applications at moderate day/night temperatures (24/18 °C), and carbon inputs (orchard grass, wheat, and rice bran) induced an initial proliferation and subsequent decline in soil density of the Fusarium wilt pathogen. This trend coincided with the onset of anaerobic conditions and a corresponding generation of various anti-fungal compounds, including volatile organic acids, hydrocarbons, and sulfur compounds. Generation of these metabolites was associated with increases in populations of Clostridium spp. Overall, carbon input and incubation temperature, but not incubation duration, significantly influenced disease suppression. All Gramineae carbon inputs altered the soil microbiome and metabolome in a similar fashion, though the timing and maximum yield of specific metabolites varied with input type. Fusarium wilt and charcoal rot suppression were superior when anaerobic soil disinfestation was conducted using standard amendment rates of 20 t ha−1 at elevated temperatures combined with a 3-week incubation period. Findings indicate that anaerobic soil disinfestation can be further optimized by modulating carbon source and incubation temperature, allowing the maximum generation of antifungal toxic volatile compounds. Outcomes also indicate that carbon input and environmental variables may influence treatment efficacy in a target pathogen-dependent manner which will require pathogen-specific optimization of treatment protocols.

Evaluation of Growth, Yield, and Biochemical Attributes of Bitter Gourd (Momordica charantia L.) Cultivars under Karaj Conditions in Iran.

Vegetative and reproductive characteristics, fruit yield, and biochemical compounds of six bitter melon cultivars (Iranshahr, Mestisa, No. 486, Local Japanese, Isfahan, and Ilocano) were evaluated under Karaj conditions in Iran. The phytochemical properties of the cultivars were evaluated using both shade-dried and freeze-dried samples at three fruit developmental stages (unripe, semi-ripe, and ripe). There were significant differences in the vegetative and reproductive characteristics among cultivars, where cv. No. 486 was superior to most vegetative attributes. The fruit yield of cultivars varied from 2.98–5.22 kg/plant. The number of days to male and female flower appearance ranged from 19.00–25.33 and from 25–33 days, respectively. The leaf charantin content was in the range of 4.83–11.08 μg/g. Fruit charantin content varied with developmental stage, drying method, and cultivar. The highest charantin content (13.84 ± 3.55 µg/g) was observed at the semi-ripe fruit stage, and it was much higher in the freeze-dried samples than the shade-dried samples. Cultivar No. 486 had the highest (15.43 ± 2.4 µg/g) charantin content, whereas the lowest charantin content (8.51 ± 1.15 µg/g) was recorded in cultivar cv. Local Japanese. The highest total phenol content (25.17 ± 2.27 mg GAE/g) was recorded in freeze-dried samples of ripe fruits of cv. No. 486, whereas the lowest phenol content was detected in the shade-dried samples of semi-ripe fruits of Isfahan. cv. Flavonoid content was higher with the shade-drying method, irrespective of cultivar. In conclusion, considering the fruit yield and active biological compounds in the studied cultivars, cv. No. 486 should be grown commercially because of its higher yield and production of other secondary metabolites.

Effects of different amino acids and their configurations on methane yield and biotransformation of intermediate metabolites during anaerobic digestion

Anaerobic digestion (AD) comprises a series of biochemical reactions, with methane as one of the target products. Amino acids (AAs) are important molecular and primary intermediate products when protein is the main component of organic waste/wastewater. The L (levorotatory, left-handed)-configuration is natural for AAs, while D (dextrorotatory, right-handed) -AAs also widely exist in the natural environment and can be generated by racemization. However, the effects and underlying mechanisms of natural AAs and their enantiomers on the methane yield and the underlying mechanisms remain unclear. In this study, the effects of certain widespread L-AAs and their enantiomers on two-stage AD and the mechanisms therein were investigated. The AAs enantiomers showed variable or even opposite effects on different processes. The methane yield from a model monosaccharide (glucose) decreased by 57% with D-leucine addition. The butyrate generation and the methane yield from propionate were sensitive to the AA configuration and were inhibited by D-leucine by 80% and 61.8%, respectively, with D-leucine addition, while the volatile fatty acids concentration was slightly increased with the addition of L-leucine. The related mechanisms were further investigated in terms of key enzymes and microbial communities. The addition of D-Leucine decreased acetic acid production from homoacetogens by 30.2% due to the inhibition of key enzymes involved in hydrogen generation and consumption. The transform of butyryl CoA to butyryl phosphate was the rate-limiting step, with the related enzyme (phosphotransbutylase) was inhibited by D-leucine. Furthermore, the bacteria related to butyric acid generation and organic matter degradation were inhibited by D-leucine, while the methanogenic archaea remained stable irrespective of leucine addition. The effect of D-AAs on microorganisms is related to the type of sludge. In this study, the methanogenetic seed sludge was granular and did not dissociate after treatment; however, the D-AAs could trigger biofilm disassembly and reduce the stability of the sludge floc. The study provides a novel method for regulating AD by adding specific AAs with L or D configuration.

Modification of phytochemical production and antioxidant activity of Dracocephalum kotschyi cells by exposure to static magnetic field and magnetite nanoparticles

Dracocephlum kotschyi Boiss is a genus in Lamiaceae family and a medicinal herb native to Iran. The cell suspension cultures were treated by static magnetic field (SMF) and Fe3O4 magnetite nanoparticles (MNP) to understand the production yield of secondary metabolites. The treatment procedure was done by cultivating the cells either with 100 ppm MNP, SMFs, or simultaneous exposure to both MNP and SMFs. The SMF at 30 mT was uniformly applied to the cells either for 3 or 4 days with a 3 h per day or a 5 h per day intervals, respectively. The contents of phenolics and phytochemicals were then examined by high performance liquid chromatography and UV–Vis spectrophotometer. These treatments imposed oxidative stress and induced polyphenol oxidase and phenylalanine ammonia lyase, accompanied by enhanced production of phenolics, anthocyanins, flavonoids, and lignin. The highest membrane embrittlement and elicitation was found upon simultaneous application of the MNPs and SMFs, followed by the MNP and SMFs. The contents of naringin, rosmarinic acid, quercetin, thymol, carvacrol, apigenin, and rutin increased in the intracellular biomass of all treated cells and extracellular culture media. These findings propose the potential of these elicitors in simultaneous production and secretion of these phytochemicals into culture media.

Production of ginsenoside by Chaetomium sp. and its effect on enhancing the contents of ginsenosides in Panax ginseng adventitious roots

Using endophytic fungi elicitors to enhance the yield of valuable secondary metabolites in plant tissue culture is an effective biotechnology strategy. In this study, we isolated an endophytic fungus Chaetomium sp. from cultivated Panax ginseng root and detected a high concentration of Rg3 in its mycelium. By comparing the effects of different treatments of Chaetomium sp. on ginsenoside production in Panax ginseng adventitious roots (PGARs), the immobilized spores of Chaetomium sp. (ISC) were proved to be the best elicitor. An initial pH of 6.5 and cocultivation time of 24 h yielded the highest ginsenosides content (56.29 ± 0.62 mg/g) in ISC-treated PGARs, increasing ginsenosides production by 3.2-fold compared with the blank group (17.56 ± 0.49 mg/g). Moreover, we show that ISC could stimulate the temporary accumulation of defense-related signal molecules, intensify the expression of defense genes in PGARs, and upregulate biosynthetic genes involved in the biosynthetic pathway of ginsenosides. Besides, the expression of the biosynthetic gene FPS (farnesyl diphosphate synthase) was deemed the most relevant factor for ginsenosides production during the elicitation period, and the L-aspartic acid secreted by Chaetomium sp. was proven to play a key role in the elicitation process. In conclusion, this study provides an accessible way of improving pharmacologically active compounds production in medicinal plants.

Productivity of medicinal raw materials by different genotypes of Matricia chammomila L. is affected with pre-sowing radiation exposure of seeds

One of the key tasks of modern pharmacology is complete and diverse use of natural raw materials - microorganisms and plants. So, different approaches of metabolism redirection were applied. Studying of plant protective reactions indicated a possibility to use various stress factors for the metabolism reorientation. One of the most effective approaches is to use ionizing and UV-C exposure. Thus, there is a shift in metabolic processes towards the formation of secondary metabolism substances with antioxidant, anticancer, immunomodulatory and anti-inflammatory effects. Biotechnological use of radiation exposure is based on the systemicity of radiobiological reactions, including protective and adaptive reactions in non-exposed organs («abscopal effect») and even in non-exposed organisms that are found in the same environment as exposed ones («by stander effect»). The products synthesized in these structures are some medicine materials and directly used by human. Radiation exposure affects developing, blocking of primary and secondary metabolism, so must be improved the selection of varieties with initial high productivity of medicinal raw materials, the choice of exposure and optimal doses inducing an increasing yield of the target metabolite and do not reduce the yield of medicinal raw materials. Effect of UV-C and X-ray pre-sowing exposure of seeds to the productivity of inflorescence formation of eight genotypes of Matricia chammomila L. was studied. There were indicated genotypes with increasing yield of inflorescence only under one or two exposure types and the variety with stimulation of flowering under UV-C exposure and absence of the marker under X-ray one.

Effect of the Carbon Source and Plant Growth Regulators (PGRs) in the Induction and Maintenance of an In Vitro Callus Culture of Taraxacum officinale (L) Weber Ex F.H. Wigg

Taraxacum officinale (L.) Weber ex F.H. Wigg, commonly known as dandelion, is a cosmopolitan and perennial weed, which has medicinal properties. In vitro propagation methods are widely used on plants that have difficulties in cultivation and, consequently, low extraction yields of active metabolites. Thus, callus culture has been considered to be useful for the accumulation of several metabolites. In this study, we aimed to establish an efficient protocol for callus induction and maintenance of T. officinale, for which explant type, carbon source, light conditions, and nine different combinations of plant growth regulators (PGRs), such as 1-naphthaleneacetic acid (NAA) (from 0.05 to 0.5 mg/L) and 6-benzylaminopurine acid (BAP) (from 0.5 to 3.0 mg/L), were evaluated. The results showed that hypocotyls and roots from sterile seedlings are the best sources for callus induction, with 100% of callogenesis at every condition tested, and more than 95% of viability and friability. Complete darkness and a medium supplemented with sucrose at 2.3% (w/v) and 0.5 mg/L of NAA and 0.5 mg/L of BAP were the best conditions for callus induction, showing callus with low organogenesis and high friability. This study provides a basis for future studies on improving large-scale callus propagation and further establishment of suspension culture systems for commercial purposes.

Endophytic fungi stimulate the concentration of medicinal secondary metabolites in houttuynia cordata thunb

ABSTRACT Endophytic fungi usually establish a symbiotic relationship with the host plant and affect its growth. In order to evaluate the impact of endophytic fungi on the Chinese herbal medicinal plant Houttuynia cordata Thunb., three endophytes isolated from the rhizomes of H. cordata, namely Ilyonectria liriodendra (IL), unidentified fungal sp. (UF), and Penicillium citrinum (PC), were co-cultured individually with H. cordata in sterile soil for 60 days. Analysis of the results showed that the endophytes stimulated the host plant in different ways: IL increased the growth of rhizomes and the accumulation of most of the phenolics and volatiles, UF promoted the accumulation of the medicinal compounds afzelin, decanal, 2-undecanone, and borneol without influencing host plant growth, and PC increased the fresh weight, total leaf area and height of the plants, as well as the growth of the rhizomes, but had only a small effect on the concentration of major secondary metabolites. Our results proved that the endophytic fungi had potential practical value in terms of the production of Chinese herbal medicines, having the ability to improve the yield and accumulation of medicinal metabolites.

Nitrogen fertilisation decreases the yield of bioactive compounds in Carlina acaulis L. grown in the field

Carlina acaulis L. can provide many valuable phytochemicals. However, the plant has a limited range and is under partial protection in many countries. Therefore, it is necessary to develop a cultivation methodology, including the mode of fertilisation. This study presents answers to the following research hypotheses: 1) C. acaulis plants can be successfully cultivated outside the natural habitat; 2) Nitrogen fertilisation of C. acaulis plants affects the yield of valuable metabolites. A cultivation experiment was carried out in a two-factor scheme with the random block method in five replicates. The research factors included the nitrogen dose (0, 4, and 8 g/m2) and the type of the nitrogen fertiliser, i.e. ammonium sulphate and calcium nitrate. The biomass yield and the metabolite content were determined with the gravimetric method and high performance liquid chromatography, respectively. It was found that C. acaulis plants were able to grow outside their natural habitat and nitrogen fertilisation negatively affected the yield of metabolites per plantation area. One hectare of cultivation without nitrogen fertilisation can provide approx. 18 kg of ursolic acid, 5 kg of oleanolic acid, 70 kg of chlorogenic acid, and 10 kg of carlina oxide. However, more research is needed to determine the effects of plant density, harvest time, and requirements for other nutrients.

Antibacterial Effect of Dihydromyricetin on Specific Spoilage Organisms of Hybrid Grouper

This study aimed to investigate the mechanism of antibacterial activity level inhibition of dihydromyricetin (DMY) against specific spoilage bacteria of grouper. Firstly, the specific spoilage bacteria of grouper in the cold storage process are Pseudomonas antarctica (P. antarctica), which are selected by calculating the spoilage metabolite yield factor. It was determined that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of DMY against grouper spoilage bacteria were 2.0 mg/mL and 6.4 mg/mL, respectively. DMY was added to the matrix of chitosan and sodium alginate, and DMY emulsions of different concentrations (0 MIC, 1 MIC, 2 MIC, 4 MIC) were prepared and characterized by differential calorimetry methods. Through analyzing cell permeability, enzyme activity, and images of the confocal laser scanning microscope (CLSM), we further studied the antibacterial mechanism of DMY emulsion on specific spoilage bacteria. The results showed that, with the increase of DMY concentration in the treatment group, the leakage of nucleic acid and protein increased significantly, the activity of ATPase and three critical enzymes in the Embden-Meyerhof-Parnas (EMP) pathway decreased significantly, and the activity of AKPase did not decrease significantly, . The metabolic activity and viability are reduced considerably. Analysis of the above results shows that DMY inhibits the growth and reproduction of P. antarctica by interfering with the metabolic activity of bacteria and destroying the function of bacterial cell membranes but has no inhibitory effect on the activity of AKPase. This study proves that DMY could be an effective and natural antibacterial agent against specific spoilage bacteria in aquatic products.

Evaluation of the Conditions for the Cultivation of Callus Cultures of Hyssopus officinalis Regarding the Yield of Polyphenolic Compounds.

The cultivation of plants in the form of callus cultures constitutes a renewable source of secondary plant metabolites. The conditions for the cultivation of callus cultures affect the yield of target compounds. Callus cultures of Hyssopus officinalis were chosen for study. Nutrient media of various compositions were used for Hyssopus officinalis callus culture. For each culture, data on the quantitative contents of saponins, flavonoids and polyphenolic compounds, as well as antioxidant activity, were obtained. It was found that Murashige and Skoog medium supplemented with 1-naphthylacetic acid and kinetin led to the highest yield of secondary metabolites.

Application of chronological lifespan in the construction of Escherichia coli cell factories

Microbial cell factories capable of producing valuable chemicals from renewable feedstocks provide a promising alternative towards sustainability. However, environmental stress remarkably affects the performance of microbial cell factories. By extending the chronological lifespan of microbial cells, the performance of microbial cell factories can be greatly improved. Firstly, an evaluation system for chronological lifespan and semi-chronological lifespan was established based on the changes in survival rates. Secondly, the addition of anti-aging drugs such as cysteine, carnosine, aminoguanidine and glucosamine increased the chronological lifespan of E. coli by 80%, 80%, 50% and 120%, respectively. Finally, we demonstrated that extending the chronological lifespan of E. coli increased the yield of metabolites produced by E. coli cell factories with endogenous (lactic acid and pyruvic acid) or exogenous (malic acid) metabolic pathway by 30.0%, 25.0%, and 27.0%, respectively. The strategy of extending chronological lifespan of E. coli provides a potential approach for enhancing the performance of microbial cell factories.

Water restriction during the vegetative and reproductive stages of Capsicum annuum var. glabriusculum, and its effect on growth, secondary metabolites and fruit yield

The fruits of Capsicum annuum var. glabriusculum, due to their culinary use, have a high market demand in southeastern Mexico. The obtained product is the result of the abiotic and biotic conditions that this species faces during its development and production under wild conditions because its cultivation has not yet been established. To advance the knowledge of the response of this chili to abiotic factors, the growth, secondary metabolite concentrations and yields of plants subjected to water deficit (WD) were evaluated during two phenological stages: vegetative and reproductive (flowering and fruiting). Two independent experiments were established, each under a completely randomized design with a 2 × 4 factorial arrangement. The treatments were a) with and without WD during the vegetative stage (VS) and b) with and without WD during the reproductive stage (RS). Each treatment comprised groups of 20 plants and had four sampling dates. The results showed that the application of WD during the VS affected the growth, accumulation of biomass, leaf area, and duration of the phenological stages of this species. During the VS, WD decreased the number and weight of plant−1 fruits (60.9 and 59.4 %, respectively) compared to the treatment without WD. In both stages, the proline content in leaves increased (93.9–100%) with WD. The concentrations of photosynthetic pigments, phenolic compounds and total flavonoids in leaves and the contents of capsaicin and dihydrocapsaicin in fruits were not affected by WD in either the VS or RS. In general, this species is more sensitive to WD applied during the VS than the RS.

Polyploidy‐promoted phenolic metabolism confers the increased competitive ability of Solidago canadensis

Allelopathy plays an important role in the successful invasion of alien invasive plants. Phenolic compounds are one of the primary classes of secondary metabolites with strong allelopathic activities. Polyploidy can cause significant effects on the production and yield of plant secondary metabolites. However, the effect of allelopathic potential of phenolic compounds on the competitiveness of different geographical cytotypes of Solidago canadensis remains unknown. We conducted a common garden field experiment in the invasive habitat of China to compare the competitive ability of native and introduced diploid, tetraploid and hexaploid S. canadensis against intentionally planted local weeds. Results showed that introduced tetraploids and hexaploids outcompeted local plants and formed a monodominant community due to superior competitive ability. Phenolic metabolism analysis showed these populations had a high accumulation of total phenolic compounds in aerial parts and rhizosphere soil throughout three developmental stages, which contributed to significant allelopathic effects on tested weeds. However, diploids and native polyploids showed less allelopathic activities due to the low level of total phenolic content. Together, these results suggest polyploidization is one of the reasons that driving the differentiation of phenolic metabolism in different geo‐cytotypes of S. canadensis, and the allelopathic abilities of introduced polyploids are further enhanced through a post‐introduction adaptive evolution. Polyploidy‐promoted allelopathic potential makes introduced polyploids more competitive against local plants than diploids and native polyploids, which contribute to its successful invasion.

Discovery and modulation of diterpenoid metabolism improves glandular trichome formation, artemisinin production and stress resilience in Artemisia annua.

Plants synthesize diverse diterpenoids with numerous functions in organ development and stress resistance. However, the role of diterpenoids in glandular trichome (GT) development and GT-localized biosynthesis in plants remains unknown. Here, the identification of 10 diterpene synthases (diTPSs) revealed the diversity of diterpenoid biosynthesis in Artemisia annua. Protein-protein interactions (PPIs) between AaKSL1 and AaCPS2 in the plastids highlighted their potential functions in modulating metabolic flux to gibberellins (GAs) or ent-isopimara-7,15-diene-derived metabolites (IDMs) through metabolic engineering. A phenotypic analysis of transgenic plants suggested a complex repertoire of diterpenoids in Artemisia annua with important roles in GT formation, artemisinin accumulation and stress resilience. Metabolic engineering of diterpenoids simultaneously increased the artemisinin yield and stress resistance. Transcriptome and metabolic profiling suggested that bioactive GA4 /GA1 promote GT formation. Collectively, these results expand our knowledge of diterpenoids and show the potential of diterpenoids to simultaneously improve both the GT-localized metabolite yield and stress resistance, in planta.

Growth kinetics, metabolite yield, and expression analysis of biosynthetic pathway genes in friable callus cell lines of Rhodiola imbricata (Edgew)

The plant cell culture provides an efficient technique for growth and production kinetics studies of bioactive compounds present in plants. Therefore, the present study investigated, for the first time, to identify the specific culture days required for higher metabolite yield in Rhodiola imbricata. A transcript-level gene expression study was conducted to understand the molecular cues associated with metabolite biosynthesis. The leaf callus cell line showed an optimum growth rate (FW: 20 g/100 mL, DW: 1.21 g/100 mL), growth index (19.00), salidroside (3.68 mg/g DW, rosavin (0.21 mg/g DW and rosarin (0.08 mg/g DW) on 24th day of the incubation period. However, salidroside, rosavin, and rosarin metabolite yield followed the growth-dependent manner in both callus cell lines, while tyrosol and p-coumaric acid showed growth independent accumulation pattern. Moreover, the antioxidant study displayed maximum phenolic content (8.07 mg/g DW) on day 18, flavonoid content (9.73 mg/g DW) on day 3, and DPPH activity (IC50; 0.79 mg/mL) on day 24 in leaf callus cell line. The RT-qPCR analysis showed upregulation of PAL, 4-HPAAS, 4-HPAAR, and UDPGT genes associated with metabolite accumulation. Expression analysis revealed a positive correlation with the metabolites yield. Furthermore, the optimized parameter could be exploited for a higher yield of specific metabolite and sequential scale-up studies. This is the first-ever study on the specific growth phase and accumulation pattern of metabolites in the friable callus cell lines of Rhodiola imbricata. Similarly, molecular signatures were also investigated to elucidate key genes associated with salidroside and rosavins biosynthesis. Furthermore, current optimized parameters lay the foundation for a cell suspension study, scale-up, and year-round metabolite production.