Methyl Jasmonate Elicitation Research Articles

Constitutive and inducible tomato defenses contribute to Bacillus thuringiensis lethality against Spodoptera exigua

In nature, insect herbivory exerts continuous selective pressure on plants that, in turn, have developed a wide array of constitutive and inducible defenses to fight against attackers. Since plant defenses may affect higher trophic levels, including entomopathogens, further research is required to understand how plant compounds influence insect-pathogens interactions and their implications for integrated pest management programs. Here, we evaluated the impact of tomato defenses on the lethality produced by the bacterial entomopathogen Bacillus thuringiensis (Bt) against second instar larvae of Spodoptera exigua. We first examined the effect of constitutive defenses from fifteen wild tomato species and forty cultivated varieties (Solanum lycopersicum) on S. exigua larval growth and susceptibility to Bt. The results showed larvae fed on wild tomato species had a reduced larval growth compared to larvae fed on cultivated varieties, whereas susceptibility to Bt was similar between both groups. We then selected six cultivated varieties, including those with high and low impacts on larval growth and Bt-induced mortality, to further explore the effect of inducible defenses. Elicitation of defenses by methyl jasmonate (MeJA) reduced larval growth and increased basal mortality. Additionally, when larvae were infected with Bt, MeJA treatment further increased their susceptibility to the entomopathogen. Metabolomic analysis confirmed a reprogramming of tomato leaf metabolism following MeJA elicitation, with an induced accumulation of bioactive compounds, such as saponins or flavonoids, known for their anti-herbivory properties in most tomato varieties. Overall, these data reveal that both constitutive and inducible tomato defenses not only protect the plant by directly affecting the insect pest but also enhance the efficacy of bacterial entomopathogens

Enhancement of Sesquiterpenoid Production by Methyl Jasmonate in Atractylodes chinensis Adventitious Root Culture and its Transcriptional Regulation.

The adventitious root (AR) culture of Atractylodes chinensis is an efficient platform for sustainable production of its sesquiterpenoid compounds (atractylon and β-eudesmol). However, their limited accumulation levels need an effective elicitation approach, and the present study solved this problem using methyl jasmonate (MeJA) as an elicitor. The effects of its treatment concentration and duration on metabolite production were investigated. The ARs treated with 100 µM MeJA for seven days increased atractylon and β-eudesmol by 3.64- and 1.90-fold, respectively, compared with the control. This study further performed transcriptome analysis to explore the transcriptional regulation mechanism of the MeJA elicitation. A total of 124,464 unigenes were identified in A. chinensis ARs, of which 3,568 genes were upregulated and 3,864 genes were downregulated under the MeJA treatment. The MeJA treatment activated the endogenous JA biosynthesis and signaling pathways and sesquiterpenoid biosynthesis. The MeJA treatment more significantly activated the MEP pathway than the MVA pathway. In addition, 14 genes encoding terpene synthase were identified to be significantly upregulated. A total of 2,700 transcription factors (TFs) were identified in A. chinensis ARs, of which Tify, MYB, and MADS were significantly enriched under the MeJA treatment. We predicted a new antagonistic interaction between MYC2 and CPP TFs, which was significantly regulated by the MeJA treatment. The results of real-time quantitative PCR and enzyme activity assays proved the reliability of the transcriptome data. This study will help improve the in vitro production system of A. chinensis sesquiterpenoids and understand the transcriptional regulation mechanism of MeJA elicitation.

Methyl Jasmonate Elicitation Enhanced Biomass, Phenolic, and Flavonoid Production of Adventitious Root Culture of Gynura procumbens in Balloon Type Bubble Bioreactor

Methyl Jasmonate Elicitation Enhanced Biomass, Phenolic, and Flavonoid Production of Adventitious Root Culture of Gynura procumbens in Balloon Type Bubble Bioreactor

Modifications in gene expression and phenolic compounds content by methyl jasmonate and fungal elicitors in Ficus carica. Cv. Siah hairy root cultures

BackgroundOne of the most effective strategies to increase phytochemicals production in plant cultures is elicitation. In the present study, we studied the effect of abiotic and biotic elicitors on the growth, key biosynthetic genes expression, antioxidant capacity, and phenolic compounds content in Rhizobium (Agrobacterium) rhizogenes-induced hairy roots cultures of Ficus carica cv. Siah.MethodsThe elicitors included methyl jasmonate (MeJA) as abiotic elicitor, culture filtrate and cell extract of fungus Piriformospora indica as biotic elicitors were prepared to use. The cultures of F. carica hairy roots were exposed to elicitores at different time points. After elicitation treatments, hairy roots were collected, and evaluated for growth index, total phenolic (TPC) and flavonoids (TFC) content, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, DPPH and ferric ion reducing antioxidant power, FRAP assays), expression level of key phenolic/flavonoid biosynthesis genes, and high-performance liquid chromatography (HPLC) analysis of some main phenolic compounds in comparison to control.ResultsElicitation positively or negatively affected the growth, content of phenolic/flavonoid compounds and DPPH and FRAP antioxidant activities of hairy roots cultures in depending of elicitor concentration and exposure time. The maximum expression level of chalcone synthase (CHS: 55.1), flavonoid 3′-hydroxylase (F3’H: 34.33) genes and transcription factors MYB3 (32.22), Basic helix-loop-helix (bHLH: 45.73) was induced by MeJA elicitation, whereas the maximum expression level of phenylalanine ammonia-lyase (PAL: 26.72) and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT: 27.57) genes was obtained after P. indica culture filtrate elicitation. The P. indica elicitation also caused greatest increase in the content of gallic acid (5848 µg/g), caffeic acid (508.2 µg/g), rutin (43.5 µg/g), quercetin (341 µg/g), and apigenin (1167 µg/g) phenolic compounds.ConclusionsThis study support that elicitation of F. carica cv. Siah hairy roots can be considered as an effective biotechnological method for improved phenolic/flavonoid compounds production, and of course this approach requires further research.

Methyl jasmonate elicitation improves the growth performance and biosynthesis of antioxidant metabolites in Portulaca oleracea through ROS modulation

The application of elicitors is regarded as one of the most efficient strategies for augmenting secondary metabolite contents in medicinal plants. There are numerous reports documenting the impact of methyl jasmonate (meJA) on plant growth and biosynthesis of secondary metabolites. However, the underlying physiological response of the plants towards meJA elicitation is understudied. Thus, the current study focused on evaluating the influence of meJA on growth performance, reactive oxygen species (ROS)/antioxidants crosstalk, and expression of bioactive metabolites in Portulaca oleracea. The seeds of P. oleracea were sown, and the plants were cultivated in pots in nursery settings. P. oleracea plants were sprayed with meJA (ranging from 0.1 to 1.0 mM) on the 35th day after sowing (DAS). The plants were harvested on the 60th DAS. The P. oleracea plants elicited with 1.0 mM meJA exhibited the highest plant height (PH), number of leaves (LN), root length (RL), fresh (FW-P), and dry weights of whole plants (DW-P). The highest increase in total anthocyanin (TAC), total chlorophyll (Total Chl), and total carotenoid (CAR) were observed in plants elicited with 0.4 mM meJA. Meanwhile, the highest increase in total phenolic content (TPC) occurred in plants elicited with 0.6 mM meJA, whereas the highest increase in total flavonoid (TFC) and ascorbic acid content (AsA) was noted in plants elicited with 0.8 mM meJA. The lowest decrease in the stress indicators, malondialdehyde (MDA) and hydrogen peroxide (H2O2) was observed in plants elicited with 0.6 mM meJA. Pearson's analysis and Partial Least Squares Regression (PLSR) were employed in exploring the relationships among all essential parameters. It was found that the antioxidant metabolites and enzymes, particularly the total soluble sugar (TSS), proline, chlorophyll a/chlorophyll b ratio (Chl a/Chl b), and superoxide dismutase (SOD) served as the most essential factors in influencing the growth performance of P. oleracea by modulating the total antioxidant activity (Total AOX) and acting as ROS scavengers. Moreover, meJA elicitation led to the distinct expression of various bioactive compounds, amplifying the medicinal properties of P. oleracea. Overall, this research indicates that meJA enhances growth performance and boosts the production of metabolites possessing medicinal values in P. oleracea.

Elicitation of salicylic acid and methyl jasmonate provides molecular and physiological evidence for potato susceptibility to infection by Erwinia carotovora subsp. carotovora

Among the range of severe plant diseases, bacterial soft rot caused by Erwinia carotovora is a significant threat to crops. This study aimed to examine the varying response patterns of distinct potato cultivars to the influence of E. carotovora. Furthermore, it seeks to highlight the potential role of salicylic acid (SA) and methyl jasmonate (MeJA) in stimulating the antioxidant defence system. We collected eight bacterial isolates from diseased and rotted tubers which were morphologically and physiologically identified as E. carotovora subsp. carotovora. We conducted a greenhouse experiment to analyse the antioxidant responses of three different potato cultivars (Diamont, Kara, and Karros) at various time intervals (2, 4, 6, 8, 12, and 24 h) after bacterial infection (hpi). We assessed the extent of disease damage by applying a foliar spray of 0.9 mM salicylic acid (SA) and 70 μM methyl jasmonate (MeJA). Inoculating with Ecc led to an increase in total phenolic levels, as well as the activities and gene expression of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POX) as time progressed. Additionally, the application of SA and MeJA resulted in a further increase relative to the diseased treatments. The Karros cultivar, unlike the Diamont and Kara cultivars, demonstrated the highest expression levels of PAL, PPO and POX through inoculation, reflecting its higher levels of activity and resistance. Furthermore, the genetic response of potato cultivars to infection at 0 hpi varied depending on their susceptibility. The examination of the rate of PAL activity upregulation following SA or MeJA stimulation clarifies the cultivars' susceptibility over time. In conclusion, the study identified E. carotovora subsp. carotovora as the most virulent isolate causing soft rot disease in potato tubers. It further revealed that the Karros cultivar displayed superior resistance with high activities and gene expression of PAL, PPO and POX, while the cv. Diamont exhibited sensitivity. Additionally, foliar exposure to SA and MeJA induced antioxidant responses, enhancing the potato plants' resistance against Ecc pathogenesis and overall plant defence.

Transcriptomic data reveals the dynamics of terpenoids biosynthetic pathway of fenugreek

Medicinal plants are rich sources for treating various diseases due their bioactive secondary metabolites. Fenugreek (Trigonella foenum-graecum) is one of the medicinal plants traditionally used in human nutrition and medicine which contains an active substance, called diosgenin, with anticancer properties. Biosynthesis of this important anticancer compound in fenugreek can be enhanced using eliciting agents which involves in manipulation of metabolite and biochemical pathways stimulating defense responses. Methyl jasmonate elicitor was used to increase diosgenin biosynthesis in fenugreek plants. However, the molecular mechanism and gene expression profiles underlying diosgening accumulation remain unexplored. In the current study we performed an extensive analysis of publicly available RNA-sequencing datasets to elucidate the biosynthesis and expression profile of fenugreek plants treated with methyl jasmonate. For this purpose, seven read datasets of methyl jasmonate treated plants were obtained that were covering several post-treatment time points (6–120 h). Transcriptomics analysis revealed upregulation of several key genes involved in diosgenein biosynthetic pathway including Squalene synthase (SQS) as the first committed step in diosgenin biosynthesis as well as Squalene Epoxidase (SEP) and Cycloartenol Synthase (CAS) upon methyl jasmonate application. Bioinformatics analysis, including gene ontology enrichment and pathway analysis, further supported the involvement of these genes in diosgenin biosynthesis. The bioinformatics analysis led to a comprehensive validation, with expression profiling across three different fenugreek populations treated with the same methyl jasmonate application. Initially, key genes like SQS, SEP, and CAS showed upregulation, followed by later upregulation of Δ24, suggesting dynamic pathway regulation. Real-time PCR confirmed consistent upregulation of SQS and SEP, peaking at 72 h. Additionally, candidate genes Δ24 and SMT1 highlighted roles in directing metabolic flux towards diosgenin biosynthesis. This integrated approach validates the bioinformatics findings and elucidates fenugreek’s molecular response to methyl jasmonate elicitation, offering insights for enhancing diosgenin yield. The assembled transcripts and gene expression profiles are deposited in the Zenodo open repository at https://doi.org/10.5281/zenodo.8155183.

Uncovering the Role of Hydroxycinnamoyl Transferase in Boosting Chlorogenic Acid Accumulation in Carthamus tinctorius Cells under Methyl Jasmonate Elicitation.

Chlorogenic acids (CGAs) are bioactive compounds widely used in the food, pharmaceutical, and cosmetic industries. Carthamus tinctorius is an important economic crop, and its suspension cells are rich in CGAs. However, little is known about the biosynthesis and regulation of CGAs in Carthamus tinctorius cells. This study first elucidated the regulatory mechanism of CGA biosynthesis in methyl jasmonate (MeJA)-treated Carthamus tinctorius cells and the role of the MeJA-responsive hydroxycinnamoyl transferase (HCT) gene in enhancing their CGA accumulation. Firstly, temporal changes in intracellular metabolites showed that MeJA increased the intracellular CGA content up to 1.61-fold to 100.23 mg·g-1. Meanwhile, 31 primary metabolites showed significant differences, with 6 precursors related to increasing CGA biosynthesis. Secondly, the transcriptome data revealed 3637 new genes previously unannotated in the Carthamus tinctorius genome and 3653 differentially expressed genes. The genes involved in the plant signaling pathway and the biosynthesis of CGAs and their precursors showed a general up-regulation, especially the HCT gene family, which ultimately promoted CGA biosynthesis. Thirdly, the expression of a newly annotated and MeJA-responsive HCT gene (CtHCT, CtNewGene_3476) was demonstrated to be positively correlated with CGA accumulation in the cells, and transient overexpression of CtHCT enhanced CGA accumulation in tobacco. Finally, in vitro catalysis kinetics and molecular docking simulations revealed the ability and mechanism of the CtHCT protein to bind to various substrates and catalyze the formation of four hydroxycinnamic esters, including CGAs. These findings strengthened our understanding of the regulatory mechanism of CGA biosynthesis, thereby providing theoretical support for the efficient production of CGAs.

Integrative effects of phytohormones in the phenolic acids production in Salvia verticillata L. under multi-walled carbon nanotubes and methyl jasmonate elicitation

Salvia verticillata L. is a well-known herb rich in rosmarinic acid (RA) and with therapeutic values. To better understand the possible roles of phytohormones in the production of phenolic acids in S. verticillata, in this work, we investigated some physiological and biochemical responses of the species to methyl jasmonate (MJ) and multi-walled carbon nanotubes (MWCNTs) as two effective elicitors. The leaves were sprayed with aqueous solutions containing 100 mg L−1 MWCNTs and 100 µM MJ and then harvested during interval times of exposure up to 96 h. The level of abscisic acid, as the first effective phytohormone, was altered in the leaves in response to MJ and MWCNTs elicitation (2.26- and 3.06-fold more than the control, respectively), followed by significant increases (P ˂ 0.05) detected in jasmonic acid and salicylic acid contents up to 8 h after exposure. Obtained data revealed that simultaneously with changes in phytohormone profiles, significant (P ˂ 0.05) rises were observed in the content of H2O2 (8.85- and 9.74-folds of control), and the amount of lipid peroxidation (10.18- and 17.01-folds of control) during the initial times after exposure to MJ and MWCNTs, respectively. Later, the content of phenolic acids increased in the elicited leaves due to changes in the transcription levels of key enzymes involved in their biosynthesis pathways, so 2.71- and 11.52-fold enhances observed in the RA content of the leaves after exposure to MJ and MWCNTs, respectively. It is reasonable to conclude that putative linkages between changes in some phytohormone pools lead to the accumulation of phenolic acids in the leaves of S. verticillata under elicitation. Overall, the current findings help us improve our understanding of the signal transduction pathways of the applied stimuli that led to enhanced secondary metabolite production in medicinal plants.

Metabolomics Reveals Rubiadin Accumulation and the Effects of Methyl Jasmonate Elicitation in Damnacanthus major Calli.

Callus suspension techniques have been considered attractive for improving bioactive metabolite productivity; methyl jasmonate (MeJA) is a widely used elicitor for stimulating synthetic pathways. In this study, a multivariate analysis-based metabolomics approach was employed to investigate the primary and specialized metabolites in the leaves, unelicited calli, and 100 or 200 μM MeJA elicited calli of Damnacanthus major. Rubiadin, a powerful anthraquinone with various therapeutic properties, was only identified in D. major calli, accumulating in a MeJA elicitation concentration-dependent manner. Callus cultures also contained high levels of amino acids, sugars, and phenolic compounds, indicating energy metabolism and metabolic adaptation responses for proliferation and stabilization. Regarding MeJA application, elicited calli contained higher amounts of quinic acid, kaempferol, and glucose with lower amounts of sucrose and raffinose than those in the unelicited control, which were closely related to protective mechanisms against MeJA. Moreover, excessive elicitation increased the asparagine, fructose, and raffinose levels and decreased the glucose and sucrose levels, which was ascribed to increased activation of the aminoacyl-tRNA biosynthesis pathway and wider utilization of glucose than of fructose after sucrose degradation. These results will be useful for optimizing plant cell culture techniques to achieve high production rates for valuable specialized metabolites.

The effect of methyl jasmonate on growth, stevioside and rebaudioside A production in Stevia rebaudiana shoot culture using mist bioreactor

Steviol glycosides (SG) from Stevia rebaudiana have been used as natural sweeteners to substitute sucrose. SG production naturally needs large biomass. Therefore, it requires large area of cultivation. In vitro cultivation can be used as an alternative to propagate Stevia, as well as for increasing the production of SG. In this experiment, we conducted Stevia propagation in bioreactor and induced SG production through methyl jasmonate (MeJa) elicitation. The objective of this study was to evaluate the effect of MeJA on plant growth and SG contents in Stevia shoot cultivated using mist bioreactor. Elicitation was carried out by MeJa spraying for 30 min every 6 h. In treatment A, we used 10 μM MeJa for 72 h and 100 μM MeJa for 24 h for treatment B. The results showed that treatment A gave higher increase in shoot growth (485%), biomass production (547%), and relative growth rate (0.13) compared to treatment B. There was no significant difference in stevioside content among treatments (A and B) and controls, meanwhile treatment B produced rebaudioside A (0.0113 mg/g) higher than treatment A (0.0062 mg/g). We concluded that treatment A was better in inducing growth and treatment B could be used to increase rebaudioside A.

Cell culture of Euphorbia fischeriana and enhancement of terpenoid accumulation through MeJA elicitation

Euphorbia fischeriana Steud is a perennial medicinal plant belonging to the Euphorbiaceae family, but its clinical application has been limited due to the scarcity of natural raw materials. Therefore, this study attempted to provide a new method for producing plant materials of E. fischeriana by cell culture. During cell culture, the effects of concentrations of plant growth regulators and sucrose were investigated to improve the culture efficiency. The results showed that the combination of 1.5 mg/L 6-benzylaminopurine and 0.2 mg/L naphthaleneacetic acid, together with a sucrose concentration of 20 g/L in the medium was appropriate for cell growth and terpenoid accumulation. Furthermore, this study applied an elicitation strategy with methyl jasmonate (MeJA) to enhance terpenoid production and investigated the involvement of signaling molecules, such as nitric oxide (NO) and hydrogen peroxide (H2O2). The results indicated that terpenoid accumulation depended on the concentration and treatment duration of MeJA. The maximum total terpenoid content was obtained when the cells were treated with 100 μM MeJA for 4 days. The levels of NO and H2O2 in the cells increased after MeJA treatment and peaked at 8 h and 18 h, respectively, suggesting the involvement of NO and H2O2 in MeJA-induced terpenoid synthesis. The findings of this study demonstrated the potential of cell culture as a method for obtaining plant materials of E. fischeriana.

Deciphering triterpenoid saponin biosynthesis by leveraging transcriptome response to methyl jasmonate elicitation in Saponaria vaccaria

Methyl jasmonate (MeJA) is a known elicitor of plant specialized metabolism, including triterpenoid saponins. Saponaria vaccaria is an annual herb used in traditional Chinese medicine, containing large quantities of oleanane-type triterpenoid saponins with anticancer properties and structural similarities to the vaccine adjuvant QS-21. Leveraging the MeJA-elicited saponin biosynthesis, we identify multiple enzymes catalyzing the oxidation and glycosylation of triterpenoids in S. vaccaria. This exploration is aided by Pacbio full-length transcriptome sequencing and gene expression analysis. A cellulose synthase-like enzyme can not only glucuronidate triterpenoid aglycones but also alter the product profile of a cytochrome P450 monooxygenase via preference for the aldehyde intermediate. Furthermore, the discovery of a UDP-glucose 4,6-dehydratase and a UDP-4-keto-6-deoxy-glucose reductase reveals the biosynthetic pathway for the rare nucleotide sugar UDP-d-fucose, a likely sugar donor for fucosylation of plant natural products. Our work enables the production and optimization of high-value saponins in microorganisms and plants through synthetic biology approaches.

Methyl jasmonate elicitation on increased production of Precocene II from adventitious root cultures of Ageratum conyzoides L. and evaluation of its antioxidant and cytotoxic activities

Methyl jasmonate elicitation on increased production of Precocene II from adventitious root cultures of Ageratum conyzoides L. and evaluation of its antioxidant and cytotoxic activities

Enhancement of taxane production in cell suspension culture of Corylus avellana L. Kalınkara by elicitation and precursor feeding

Paclitaxel (trademark Taxol®) is the most effective chemotherapeutic agent against a wide range of cancers. Hazelnut (Corylus avellana L.) cell culture is a promising and inexpensive strategy for producing paclitaxel and related taxanes. This study evaluated the effect of elicitation and taxane precursor feeding for the enhancement of taxanes in a Turkish hazelnut (C. avellana cv. ‘Kalınkara’) cell suspension culture. Elicitor methyl jasmonate (100, 200 and 300 µmol L−1) and precursor phenylalanine (3μmol, 3 and 6 mmol L−1) were tested in cell suspension cultures. While methyl jasmonate increased the accumulation of taxanes, especially cephalomannine, via induction of the paclitaxel biosynthetic pathway, phenylalanine slightly induced the conversion of 10-deacetylbaccatin III and baccatin III to the end product paclitaxel (0.5349 µg g−1). The results showed that 200 µmol L−1 methyl jasmonate led to significantly greater induction of taxanes than 100 and 300 µmol L−1. The amount of cephalomannine (331.6 µg g−1) in cell suspension cultures elicited by 200 µmol L−1 methyl jasmonate was 8-fold higher than that in the control (41.61 µg g−1), while 10-deacetylbaccatin III (6.174 µg g−1) and baccatin III (3.956 µg g−1) increased almost twice as much as the control. The highest total paclitaxel yield was 5.453 µg g−1 in the same culture conditions. In conclusion, cell culture systems of C. avellana L. cv. ‘Kalınkara’ hazelnut, established for the first time, may become a potential candidate for industrial-level production of cephalomannine and other taxanes with further optimization.

Methyl Jasmonate Elicitation for In Vitro Lycorine Accumulation in Three Zephyranthes Species and Comparative Analysis of Tissue-Cultured and Field Grown Plants

Lycorine is an important Amaryllidaceae alkaloid showing anti-cancerous activity on numerous cell lines; and it also demonstrates antiviral activity against several viruses including SARS-CoV-2 responsible for COVID-19. The in vitro cultivation of plant parts is a good alternative for elicitor mediated secondary metabolite synthesis, mass propagation, and cloning of elite genotypes. In this study, the quantification of lycorine from Zephyranthes candida, Zephyranthes grandiflora, and Zephyranthes citrina was evaluated, and the influence of methyl jasmonate (MJ) treatments on accumulation of lycorine yield was observed in the in vitro cultivated tissues. The influence of methyl jasmonate (MJ) on accumulation of lycorine was investigated for the first time in in vitro regenerated bulb, leaf, and root tissues of Zephyranthues. The efficient in vitro shoot regeneration was achieved in Z. candida (73.9%), Z. grandiflora (85.5%), and Z. citrina (76.5%) on Murashige and Skoog (MS) medium amended with 2.0 mg·L−1 Naphthalene acetic acid + 0.5 mg·L−1 Benzylaminopurine. The regenerants had the highest i.e., 7.46 mean numbers of bulblets per shoot. The best root induction (80.66%) was achieved on 2.0 mg/L Indole butyric acid (IBA). The lycorine content was quantified through High performance thin layer chromatography (HPTLC) in three field grown Zephyranthes species, was highest in Z. candida (1.93 µg g−1 dry wt.), followed by Z. grandiflora (1.87 µg g−1 dry wt.) and Z. citrina (1.62 µg g−1 dry wt.). The yield of lycorine was observed in this order i.e., bulb > leaf > root. The regenerated plants were supplemented with MJ and maximum lycorine yield was noted at 100 µM in bulb tissues of Z. candida (2.74 µg g−1 dry wt.) with an increase in percentage of 39.08. The enhancement could be due to MJ-induced stress as the biochemical attributes and anti-oxidant enzyme activity were high with elevated level of MJ. This enrichment may auger commercial manufacturing and utilization of lycorine in future.

Methyl jasmonate elicitation effect on the metabolic profile of cambial meristematic cells culture derived from sweet basil (Ocimum basilicum L.) in relation to antioxidant activity: Untargeted metabolomics study in a time-based approach

The undifferentiated cambial meristematic cell (CMC) has been recognized as a value-added production platform for plant natural products in comparison to the dedifferentiated plant cell line (DDC). In a time-based approach at 0, 24, 48, and 72 h, the present study aimed at investigating the phytochemical metabolome of methyl jasmonate (MeJA)-elicited CMC cultures derived from sweet basil (Ocimum basilicum L.), including primary and secondary metabolites analyzed using GC/TOF-MS post-silylation and RP-UPLC-C18-FT-MS/MS, respectively, as well as the analysis of aroma composition using headspace SPME-GC-MS. The results revealed a stress response in primary metabolism manifested by an increase in amino and organic acids reaching their maximum levels after 48 (1.3-fold) and 72 (1.7-fold) h, respectively. In addition, phenolic acids (e.g., sagerinic acid, rosmarinic acid, and 3-O-methylrosmarinic acid) followed by flavonoid aglycones (e.g., salvigenin and 5,6,4′-trihydroxy-7,3′-dimethoxyflavone) were the most abundant with prominent increases at 48 (1.2-fold) and 72 (2.1-fold) h, respectively. The aroma was intensified by the elicitation along the time, especially after 48 and 72 h. Furthermore, multivariate data analyses, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) confirmed elicitation effect, especially post 48 and 72 h. The study further assessed the effect of MeJA elicitation on the antioxidant and polyphenolic content. The cultures at 48 h demonstrated a significant (p < 0.05) antioxidant activity concurrently with correlation with total polyphenolic content using Pearson's correlation. Our study provides new insights to the elicitation impact on primary and secondary metabolism, in addition to aroma profile, to orchestrate the stress response and in relation to antioxidant effect.

Comparative analysis of salidroside and rosavin accumulation and expression analysis of biosynthetic genes in salicylic acid and methyl jasmonate elicited cell suspension culture of Rhodiola imbricata (Edgew.)

Elicitation has been shown to be a very effective tool for improving bioactive molecule accumulation in various cell culture systems. The current study observed the effects of salicylic acid (SA) and methyl jasmonate (MeJA) on the increased accretion of salidroside and rosavin, as well as the transcriptional response of their biosynthetic genes in Rhodiola imbricata cell suspension culture. Suspension-cultured cells were treated with different concentrations of elicitors (SA and MeJA; 25, 50, 75, and 100 μM) on the 16th day of the incubation period and evaluated for growth biomass, metabolite content, and gene expression analysis after 24, 48, 72, and 96 h of elicitor treatment. The enhanced salidroside (7.71 mg/g DW) and rosavin (0.99 mg/g DW) contents were achieved in 50 μM SA elicitation. Similarly, MeJA elicitation improved salidroside (1.85 mg/g DW) and rosavin (0.67 mg/g DW) content in 100 μM concentration. In 50 μM SA and 100 μM MeJA elicitation, total phenolics were significantly increased (16.11 mg/g DW; 7.69 mg/g DW). Total flavonoids were detected at their highest levels (9.78 mg/g DW; 6.69 mg/g DW) in 50 μM SA and 100 μM MeJA elicitation, respectively. Furthermore, after SA and MeJA treatment, transcript level gene expression revealed a higher expression pattern of aromatic-L-amino-acid decarboxylase (TDC) and Uridine 5′ -diphospho-glucuronosyltransferase (UGT 73 C) genes in salidroside biosynthesis. While in rosavin biosynthesis, SA and MeJA elicitation significantly increased the expression levels of cinnamyl alcohol dehydrogenase (CAD) and cinnamoyl-CoA reductase (CCR). Overall, the study suggests that elicitation of SA and MeJA improved specialized metabolite accumulation and expression of key pathway genes in R. imbricata suspension-cultured cells.

Assessment of the In-vitro Potential of Two Different Genotypes of Bacopa Monnieri L. Pennell

Jal Brahmi (Bacopa monnieri L.) is an important medicinal herb rendering mental health-promoting activities. In-vitro mass multiplication of elite genotypes of Jal Brahmi may bring off its high industrial demand. In the present study, the comparative in-vitro responses of two diverse genotypes (DBM-4 and DBM-12) were assessed. Direct shoot organogenesis was reported in both genotypes studied in basal MS medium media. However, both genotypes formed calli in the presence of 2, 4-D and IAA. Germplasm DBM-4 observed significantly higher antioxidant potential than that of DBM-12. Further, in both genotypes, methyl jasmonate elicitation significantly improved the antioxidant potential and total phenolic contents of the callus. Hence, DBM-4 has the potential for in-vitro mass multiplication and secondary metabolites production.

Safflower Flavonoid 3'5'Hydroxylase Promotes Methyl Jasmonate-Induced Anthocyanin Accumulation in Transgenic Plants.

Flavonoids are the most abundant class of secondary metabolites that are ubiquitously involved in plant development and resistance to biotic and abiotic stresses. Flavonoid biosynthesis involves multiple channels of orchestrated molecular regulatory factors. Methyl jasmonate (MeJA) has been demonstrated to enhance flavonoid accumulation in numerous plant species; however, the underlying molecular mechanism of MeJA-induced flavonoid biosynthesis in safflower is still not evident. In the present study, we revealed the underlying molecular basis of a putative F3'5'H gene from safflower imparting MeJA-induced flavonoid accumulation in transgenic plants. The constitutive expression of the CtF3'5'H1 gene was validated at different flowering stages, indicating their diverse transcriptional regulation through flower development in safflower. Similarly, the CtF3'5'H1-overexpressed Arabidopsis plants exhibit a higher expression level, with significantly increased anthocyanins and flavonoid content, but less proanthocyanidins than wild-type plants. In addition, transgenic plants treated with exogenous MeJA revealed the up-regulation of CtF3'5'H1 expression over different time points with significantly enhanced anthocyanin and flavonoid content as confirmed by HPLC analysis. Moreover, CtF3'5'H1- overexpressed Arabidopsis plants under methyl violet and UV-B irradiation also indicated significant increase in the expression level of CtF3'5'H1 with improved anthocyanin and flavonoid content, respectively. Noticeably, the virus-induced gene silencing (VIGS) assay of CtF3'5'H1 in safflower leaves also confirmed reduced anthocyanin accumulation. However, the CtF3'5'H1 suppression in safflower leaves under MeJA elicitation demonstrated significant increase in total flavonoid content. Together, our findings confirmed that CtF3'5'H1 is likely mediating methyl jasmonate-induced flavonoid biosynthesis in transgenic plants via enhanced anthocyanin accumulation.