Production Of Secondary Metabolites Research Articles

A critical review on the active anti-viral metabolites of bioprospecting traditionally used plant species from semi-arid regions of the subcontinent.

Plants are crucial medicinal resources, with 80 % of people relying on them for primary healthcare. The search for natural antiviral compounds is increasing, especially in semi-arid ecosystems where abiotic stress promotes the production of beneficial secondary metabolites. This review highlights semi-arid plants with the potential as functional foods to combat viral diseases and other illnesses. Literature was searched in databases like ScienceDirect to gather information on novel compounds from stress-tolerant semi-arid plant species. These compounds have potential uses in treating viral infections and other health issues such as diabetes and high blood pressure. The review screened 61 semi-arid plants known for their antiviral metabolites. Eight plants were identified with novel antiviral compounds. Key metabolites include agathisflavone, pectic arabinogalactan, azadirachtin, aloin, aloe-emodin, aloesaponarin I, allicin, terpenoids, chlorogenic acids, curcumin, chromones, β-sitosterol, lupeol, oleuropein, carissol, β-amyrin, and ∆-9-tetrahydrocannabinol. Stress-tolerant semi-arid plants are significant sources of metabolites for treating infectious diseases and boosting immune systems. Further research on these metabolites in animal models is needed to verify their efficacy for treating human diseases during endemic and pandemic outbreaks, such as COVID-19.

The Gut Microbiome and Lignocellulose Digestion in Constrictotermes cyphergaster (Termitidae: Nasutitermitinae): A Termite Incorporating Lichen into Its Diet

Lichen-feeding termites occupy a distinctive ecological niche. This feeding behavior underscores a complex interplay between the termites’ digestive abilities and the biochemical properties of lichens, known for their resilience and production of secondary metabolites. Understanding the dietary preferences and digestive mechanisms of these termites offers insights into their ecological roles and the evolutionary adaptations that enable them to exploit such a specialized food source. We conducted experiments with Constrictotermes cyphergaster, feeding it with different combinations of its natural food sources: wood bark and lichen from host trees. Gut microbial communities were analyzed through 16S rRNA sequencing and shotgun metagenomics. Our results revealed that a diet containing lichens induces a shift in microbiota composition and increases the abundance of genes encoding an AA3 enzyme with a role in lignin digestion. This study emphasizes the potential role of lichens in enhancing the digestive capabilities of termites, highlighting the intricate relationships between diet, gut microbiota, and enzymatic activity in Termitidae.

Stress Responses to Bark Beetle Infestations among Pine (Pinus sylvestris), Fir (Abies alba), and Beech (Fagus sylvatica) Trees

Insect infestation triggers multiple defense responses in plants, both locally at the infection site and systemically throughout the plant, including the production of feeding deterrents, toxins, defensive proteins, enzymes, and secondary metabolites. Our study aimed to compare the endogenous levels of antioxidative enzymes, photosynthetic pigments, phytohormones, total phenols, and flavonoids in bark-beetle-infested and uninfested trees. We evaluated the surviving trees in bark-beetle-infested stands, assessing both the condition and defense of uninfested and infested beech (Fagus sylvatica), pine (Pinus sylvestris), and fir (Abies alba) trees. Sampling was performed at six affected sites in the Czech Republic, targeting trees that were resilient to significant health deterioration caused by abiotic and biotic factors. The results showed different levels of most of the measured compounds in the three species. Among all the tested species, photosynthetic pigment levels showed the strongest association with infestation status, which was generally lower in the infested plants. For chlorophyll a, extremely significant reductions were observed from 123 ± 20.6 to 101 ± 17.9 μg/g dry weight (DW) in pine, from 231 ± 33.1 to 199 ± 22.2 μg/g DW in beech, and from 60 ± 5.66 to 51.3 ± 6.27 μg/g DW in fir. In contrast, enzymatic activities indicated only isolated instances of significant association, whereas antioxidative properties (total phenolic content, flavonoids, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity) were not significantly associated with infestation status. There was a statistically significant increase in glutathione reductase activity in infested fir and pine trees. However, this difference was not statistically significant in beech. In contrast, a significant increase in superoxide dismutase activity was detected in infected beech trees. Phytohormones have emerged as the most diverse group of analyzed compounds. Cytokinins were the most distinct, with many of them being significantly increased in infested pines, whereas both beech and fir showed only one significant association. Additionally, derivatives of jasmonic acid also showed a distinct pattern of change associated with bark beetle infestation, with the levels of three out of the four analyzed jasmonates being significantly decreased in infested pines, whereas no effects were observed in beeches and firs. Notably, many phytohormones were significantly elevated in the infested pine, whereas both beech and fir exhibited only one significant association. Overall, the data showed that pines responded differently to bark beetles than to beeches or firs. The greatest changes in phytohormones were observed in pine, whereas the most significant changes in photosynthetic pigments were observed in beech and fir trees.

Characterization and quantification of peptaibol produced by novel Trichoderma spp: Harnessing their potential to mitigate moisture stress through enhanced biochemical and physiological responses in black pepper (Piper nigrum L.).

Trichoderma spp. is primarily applied to manage biotic stresses in plants. Still, they also can mitigate abiotic stresses by the stimulation of antioxidative protective mechanisms and enhanced synthesis of secondary metabolites. The study optimized the conditions to enhance peptaibol production by novel Trichoderma spp, characterized and quantified peptaibol- alamethicin using HPLC and LC MS-MS. The present study investigated these isolates efficacy in enhancing growth and the associated physio-biochemical changes in black pepper plants under moisture stress. Under in vitro conditions, out of 51 isolates studied, six isolatesviz., T. asperellum (IISR NAIMCC 0049), T. erinaceum (IISR APT1), T. harzianum (IISR APT2), T. harzianum (IISR KL3), T. lixii (IISR KA15) and T. asperellum (IISR TN3) showed tolerance to low moisture levels (5, 10 and 20%) and higher temperatures (35 and 40°C). In vivo evaluation on black pepper plants maintained under four different moisture levels (Field capacity [FC]; 75%, 50%, and 25%) showed that the plants inoculated with Trichoderma accumulated greater quantities of secondary metabolites viz., proline, phenols, MDA and soluble proteins at low moisture levels (50% and 25% FC). In the present study, plants inoculated with T. asperellum and T.harzianum showed significantly increased growth compared to uninoculated plants. The shortlisted Trichoderma isolates exhibited differences in peptaibol production and indicated that the peptide might be the key factor for their efficiency as biocontrol agents. The present study also demonstrated that Trichoderma isolates T. harzianum and T. asperellum (IISR APT2 & NAIMCC 0049) enhanced the drought-tolerant capabilities of black pepper by improving plant growth and secondary metabolite production.

Proteomics fingerprinting reveals importance of iron and oxidative stress in Streptomyces scabies–Solanum tuberosum interactions

IntroductionThe Gram-positive actinobacterium Streptomyces scabies is the major causal agent of potato common scab. The main pathogenicity factor is thaxtomin A, a phytotoxin that causes atypical cell death, although other secondary metabolites have been described to play a role in S. scabies virulence. Despite this, many aspects of the interaction between S. scabies and its primary host Solanum tuberosum L. remain to be elucidated.MethodsIntracellular proteins of S. scabies EF-35 grown in the presence of in vitro produced tubers (microtubers) of the Russet Burbank and Yukon Gold potato cultivars were extracted and analysed by electrospray mass spectrometry (ES MS/MS). Based on the results of proteomic analysis, iron quantification by ICP-MS and nitrite quantification using Griess reagent in growth media as well as RT-qPCR analysis of the siderophore pyochelin gene expression were performed in the presence and absence of microtubers. Hydrogen peroxide accumulation was also determined in the nutrient medium used for co-cultivation of bacteria and potato microtubers.ResultsPotato microtubers caused an increase in the content of bacterial proteins involved in stress and defense, secondary metabolism, and cell differentiation, as well as secreted proteins. Co-cultivation with potato microtubers induced the accumulation of S. scabies proteins implicated in siderophore pyochelin biosynthesis, nitrite production and oxidative stress perception and response. The increase in the abundance of proteins related to pyochelin biosynthesis was consistent with a significant decrease in the iron content in the culture medium, as well as with induction of expression of pyochelin biosynthesis genes. Elevated nitrite/sulfite reductase protein levels were associated with increased nitrite excretion by S. scabies cells in the presence of host microtubers. The increase in the levels of proteins associated with signaling and oxidative stress response could have been caused by the accumulation of ROS, in particular hydrogen peroxide, detected in the studied system.DiscussionThese findings show that interactions of S. scabies with living potato microtubers induce the production of secondary metabolites, defense responses, and protection from oxidative stress. This study suggests the importance of iron during host - S. scabies interactions, resulting in competition between pathogen and its host.

Phenolic Bisabolane Sesquiterpene Derivatives from an Arctic Marine-derived Fungus Aspergillus sydowii MNP-2

Background:: Filamentous fungi in the genus Aspergillus are well known for their important roles in production of bioactive secondary metabolites with diversely chemical structures and potential application in pharmaceutical industry. Objective:: The present study aimed to investigate the phenolic bisabolane sesquiterpene (PBS) derivatives from an Arctic marine-derived fungus Aspergillus sydowii MNP-2. Methods:: In this study, antimicrobial activities were carried out according to the broth microdilution assay, nitric oxide (NO) production in mouse macrophages (RAW264.7) and BV2 microglial cells was used to detect the inhibitory effect of compounds in inflammatory reactions, and in vitro inhibitory cell proliferation activity was determined by the cell counting kit-8 (CCK-8) assay. Results:: In this work, chemical investigation of an Arctic marine-derived strain A. sydowii MNP-2 led to the isolation of 11 PBSs (1-11) using various chromatographic methods. Their chemical structures were unambiguously determined by 1H NMR spectroscopy and mass spectrometry analyses as well as comparison with literature data. It is noteworthy that compounds 1, 7 and 11 were firstly obtained from A. sydowii. Antimicrobial assay showed that these chemicals had no potent inhibitory effect on Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values > 16 μg/mL. Additionally, the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)- induced inflammation in mouse macrophages (RAW264.7) and BV2 microglial cells were all below 10% for compounds 4-6 and 8, indicating almost negligible anti-inflammatory efficacy. Among the tested compounds 4-6 and 8 for tumor-cell proliferation inhibition activities, compound 5 demonstrated the strongest inhibitory effect against human acute promyelocytic leukemia cells (HL-6) with a 44.76% inhibition rate. Conclusion:: In the present study, 11 PBS derivatives were purified and characterized from the solidand liquid-state fermentations of the Arctic marine-derived fungus A. sydowii MNP-2. Unfortunately, none of these metabolites had significant antimicrobial, anti-inflammatory, or tumor-cell proliferation inhibition activities.

Assessing the potential role of arbuscular mycorrhizal fungi in improving the phytochemical content and antioxidant properties in Gomphrena globosa

Strategies to increase the secondary metabolite production, obtained from medicinal plants has been the topic of research in recent years. The symbiotic interaction between arbuscular mycorrhizal fungi and plants allows host-fungus pairings to enhance secondary metabolite synthesis. Therefore, the current study investigated the effect of inoculating two distinct AMF species discretely as well as in conjunction on the flower-derived secondary metabolites in Gomphrena globosa. The findings showed that the plants inoculated with combined treatment exhibited higher total phenolic (50.11 mg GAE/g DW), flavonoids (29.67 mg QE/g DW), saponins (122.55 mg DE/g DW), tannins (165.71 TAE/g DW) and terpenoid (8.24 mg LE/g DW) content in the methanolic extract. HPTLC examination showed the existence of kaempferol and benzoic acid with the highest amount (0.90% and 5.83% respectively) observed in the same treatment. FTIR analysis revealed functional group peaks with increased peak intensity in the combination treatment. Higher antioxidant activities such as DPPH (IC50: 401.39 µg/mL), ABTS (IC50: 71.18 µg/mL) and FRAP (8774.73 µM Fe (II) equivalent) were observed in the methanolic extract of combined treatment. To our knowledge, this is the first study on the impact of AMF inoculation on bioactive compounds and antioxidant activities in G. globosa flowers. Moreover, this study could lead to the development of novel pharmaceuticals and herbal remedies for various diseases.

Evolution of small molecule-mediated regulation of arbuscular mycorrhiza symbiosis.

The arbuscular mycorrhizal (AM) symbiosis formed by most extant land plants with symbiotic fungi evolved 450 Ma. AM promotes plant growth by improving mineral nutrient and water uptake, while the symbiotic fungi obtain carbon in return. A number of plant genes regulating the steps leading to an efficient symbiosis have been identified; however, our understanding of the metabolic processes involved in the symbiosis and how they were wired to symbiosis regulation during plant evolution remains limited. Among them, the exchange of chemical signals, the activation of dedicated biosynthesis pathways and the production of secondary metabolites regulating late stages of the AM symbiosis begin to be well described across several land plant clades. Here, we review our current understanding of these processes and propose future directions to fully grasp the phylogenetic distribution and role played by small molecules during this ancient plant symbiosis. This article is part of the theme issue 'The evolution of plant metabolism'.

Expanded Gene Regulatory Network Reveals Potential Light-Responsive Transcription Factors and Target Genes in Cordyceps militaris

Cordyceps militaris, a fungus widely used in traditional Chinese medicine and pharmacology, is recognized for its abundant bioactive compounds, including cordycepin and carotenoids. The growth, development, and metabolite production in various fungi are influenced by the complex interactions between regulatory cascades and light-signaling pathways. However, the mechanisms of gene regulation in response to light exposure in C. militaris remain largely unexplored. This study aimed to identify light-responsive genes and potential transcription factors (TFs) in C. militaris through an integrative transcriptome analysis. To achieve this, we reconstructed an expanded gene regulatory network (eGRN) comprising 507 TFs and 8662 regulated genes using both interolog-based and homolog-based methods to build the protein–protein interaction network. Aspergillus nidulans and Neurospora crassa were chosen as templates due to their relevance as fungal models and the extensive study of their light-responsive mechanisms. By utilizing the eGRN as a framework for comparing transcriptomic responses between light-exposure and dark conditions, we identified five key TFs—homeobox TF (CCM_07504), FlbC (CCM_04849), FlbB (CCM_01128), C6 zinc finger TF (CCM_05172), and mcrA (CCM_06477)—along with ten regulated genes within the light-responsive subnetwork. These TFs and regulated genes are likely crucial for the growth, development, and secondary metabolite production in C. militaris. Moreover, molecular docking analysis revealed that two novel TFs, CCM_05727 and CCM_06992, exhibit strong binding affinities and favorable docking scores with the primary light-responsive protein CmWC-1, suggesting their potential roles in light signaling pathways. This information provides an important functional interactive network for future studies on global transcriptional regulation in C. militaris and related fungi.

Mutual interaction of the entomopathogenic and endophytic fungus Metarhizium anisopliae with zearalenone as a native component of crude Fusarium extract

The present study revealed the consequences of the interaction of a widely used bioinsecticide and endophyte Metarhizium anisopliae with the hazardous mycotoxin zearalenone (ZEN) as a pure substance and with ZEN as a native component of a crude Fusarium extract. In the environment, microorganisms encounter a mixture of metabolites secreted by other organisms living in the same area, not single substances. The obtained results suggest that M. anisopliae, exposed to a variety of active substances produced by Fusarium graminearum, is able to eliminate ZEN. Within 14 days, M. anisopliae biotransformed 90.8% and 85.8% of ZEN as a pure substance and ZEN as a native component of the F. graminearum extract from Rice Medium (E-Fg-RM), respectively, through reduction predominantly to α-epimers of zearalenols and zearalanols, considered more estrogenic than ZEN, which can raise concerns. Compared to pure ZEN, E-Fg-RM significantly affected the production of Metarhizium secondary metabolites by increasing the destruxins amount by approximately 20–25% and reducing the swainsonine content by 96.2%. All these findings provide a possible picture of the interaction of M. anisopliae with ZEN in the wild, mainly as a result of the use of crude extract from Fusarium, which contained a mixture of different metabolites.

Carbon dot unravels accumulation of triterpenoid in Evolvulus alsinoides hairy roots culture by stimulating growth, redox reactions and ANN machine learning model prediction of metabolic stress response

Evolvulus alsinoides, a therapeutically valuable shrub can provide consistent supply of secondary metabolites (SM) with pharmaceutical significance. Nonetheless, because of its short life cycle, fresh plant material for research and medicinal diagnostics is severely scarce throughout the year. The effects of exogenous carbon quantum dot (CD) application on metabolic profiles, machine learning (ML) prediction of metabolic stress response, and SM yields in hairy root cultures of E. alsinoides were investigated and quantified. The range of the particle size distribution of the CDs was between 3 and 7 nm. The CDs EPR signal and spin trapping experiments demonstrated the formation of O2-•spin-adducts at (g = 2.0023). Carbon dot treatment increased the levels of hydrogen peroxide and malondialdehyde concentrations as well as increased antioxidant enzyme activity. CD treatments (6 μg mL-1) significantly enhanced the accumulation of squalene and stigmasterol (7 and 5-fold respectively). The multilayer perceptron (MLP) algorithm demonstrated remarkable prediction accuracy (MSE value = 1.99E-03 and R2 = 0.99939) in both the training and testing sets for modelling. Based on the prediction, the maximum oxidative stress index and enzymatic activities were highest in the medium supplemented with 10 μg mL-1 CDs. The outcome of this study indicated that, for the first time, using CD could serve as a novel elicitor for the production of valuable SM. MLP may also be used as a forward-thinking tool to optimize and predict SM with high pharmaceutical significance. This study would be a touchstone for understanding the use of ML and luminescent nanomaterials in the production and commercialization of important SM.

Transcriptomic and protein analysis of Trametes versicolor interacting with a Hypholoma fasciculare mycelium foraging in soil

The decomposition of large woody material is an important process in forest carbon cycling and nutrient release. Cord-forming saprotrophic basidiomycete fungi create non-resource limited mycelial networks between decomposing branches, logs and tree stumps on the forest floor where colonisation of new resources is often associated with the replacement of incumbent decay communities. To date, antagonism experiments have mostly placed competing fungi in direct contact, while in nature cord-forming saprobes encounter colonised wood as mycelia in a network. Transcriptomic and peptide analyses were conducted on soil-based microcosms were foraging cord-forming Hypholoma fasciculare encountered a wood block colonised by Trametes versicolor. Protein turnover featured strongly for both species and genes putatively involved in secondary metabolite production were identified. H. fasciculare demonstrated an exploitative profile with increased transcription of genes associated with carbohydrate metabolism and RNA and ribosome processing. T. versicolor showed a shift in signalling, energy generation and amino acid metabolism. By identifying genes and proteins putatively involved in this fungal interaction, this work may help guide the discovery of bioactive molecules and mechanisms underpinning community succession.

Cofactor recycling strategies for secondary metabolite production in cell-free protein expression systems

Cofactor recycling strategies for secondary metabolite production in cell-free protein expression systems

The Influence of Rhizobial Nod Factors on the Synthesis of Flavonoids in Common Buckwheat (Fagopyrum esculentum Moench)

Flavonoids constitute a class of polyphenolic secondary metabolites synthesised mainly by plants and possessing anticancer, antioxidant, anti-inflammatory, and antiviral properties. Common buckwheat (F. esculentum Moench) is a dicotyledonous plant rich in different classes of flavonoids (e.g., rutin) and other phenolic compounds. Lipochitooligosaccharides (LCOs), i.e., rhizobial Nod factors and important signalling molecules for the initiation of symbiosis with legumes, are very effective mitogens that stimulate cell division in plant meristems and the production of secondary metabolites. They can also act in this way in non-legume plants. It has been shown that rhizobial Nod factors noticeably improve plant growth. Rhizobial Nod factors influence the production of flavonoids in common buckwheat grown in greenhouse conditions. The amount of rutin and isoorientin in leaves and flowers has been shown to increase in a statistically significant way after application of Nod factors to buckwheat seeds. The presence of rhizobial Nod factors has no influence on the flavonoid content in stems and roots.

Mitigating gadolinium toxicity in guar (Cyamopsis tetragonoloba L.) through the symbiotic associations with arbuscular mycorrhizal fungi: physiological and biochemical insights

BackgroundGadolinium (Gd) is an increasingly found lanthanide element in soil; thus, understanding its impact on plant physiology, biochemistry, and molecular responses is crucial. Here, we aimed to provide a comprehensive understanding of Gd (150 mg kg− 1) impacts on guar (Cyamopsis tetragonoloba L.) plant yield and metabolism and whether the symbiotic relationship with arbuscular mycorrhizal fungi (AMF) can mitigate Gd toxicity of soil contamination.ResultsAMF treatment improved mineral nutrient uptake and seed yield by 38–41% under Gd stress compared to non-inoculated stressed plants. Metabolic analysis unveiled the defense mechanisms adopted by AMF-treated plants, revealing carbon and nitrogen metabolism adaptations to withstand Gd contamination. This included an increase in the synthesis of primary metabolites, such as total sugar (+ 39% compared to control), soluble sugars (+ 29%), starch (+ 30%), and some main amino acids like proline (+ 57%) and phenylalanine (+ 87%) in the seeds of AMF-treated plants grown under Gd contamination. Furthermore, fatty acid and organic acid profile changes were accompanied by the production of secondary metabolites, including tocopherols, polyamines, phenolic acids, flavones, and anthocyanins.ConclusionsOverall, the coordinated synthesis of these compounds underscores the intricate regulatory mechanisms underlying plant-AMF interactions and highlights the potential of AMF to modulate plant secondary metabolism for enhanced Gd stress tolerance.

Bioinformatics Identification and Expression Analysis of Acetyl-CoA Carboxylase Reveal Its Role in Isoflavone Accumulation during Soybean Seed Development.

Isoflavones belong to the class of flavonoid compounds, which are important secondary metabolites that play a crucial role in plant development and defense. Acetyl-CoA carboxylase (ACCase) is a biotin-dependent enzyme that catalyzes the conversion of Acetyl-CoA into Malonyl-CoA in plants. It is a key enzyme in fatty acid synthesis and also catalyzes the production of various secondary metabolites. However, information on the ACC gene family in the soybean (Glycine max L. Merr.) genome and the specific members involved in isoflavone biosynthesis is still lacking. In this study, we identified 20 ACC family genes (GmACCs) from the soybean genome and further characterized their evolutionary relationships and expression patterns. Phylogenetic analysis showed that the GmACCs could be divided into five groups, and the gene structures within the same groups were highly conserved, indicating that they had similar functions. The GmACCs were randomly distributed across 12 chromosomes, and collinearity analysis suggested that many GmACCs originated from tandem and segmental duplications, with these genes being under purifying selection. In addition, gene expression pattern analysis indicated that there was functional divergence among GmACCs in different tissues. The GmACCs reached their peak expression levels during the early or middle stages of seed development. Based on the transcriptome and isoflavone content data, a weighted gene co-expression network was constructed, and three candidate genes (Glyma.06G105900, Glyma.13G363500, and Glyma.13G057400) that may positively regulate isoflavone content were identified. These results provide valuable information for the further functional characterization and application of GmACCs in isoflavone biosynthesis in soybean.

Significance of research on natural products from marine-derived Aspergillus species as a source against pathogenic bacteria.

Bacterial infections pose a significant clinical burden on global health. The growing incidence of drug-resistant pathogens highlights the critical necessity to identify and isolate bioactive compounds from marine resources. Marine-derived fungi could provide novel lead compounds against pathogenic bacteria. Due to the particularity of the marine environment, Aspergillus species derived from marine sources have proven to be potent producers of bioactive secondary metabolites and have played a considerable role in advancing drug development. This study reviews the structural diversity and activities against pathogenic bacteria of secondary metabolites isolated from marine-derived Aspergillus species over the past 14 years (January 2010-June 2024), and 337 natural products (including 145 new compounds) were described. The structures were divided into five major categories-terpenoids, nitrogen-containing compounds, polyketides, steroids, and other classes. These antimicrobial metabolites will offer lead compounds to the development and innovation of antimicrobial agents.

Contextualized Metabolic Modelling Revealed Factors Affecting Isoflavone Accumulation in Soybean Seeds.

Isoflavones, secondary metabolites with numerous health benefits, are predominantly found in legume seeds, especially soybean; however, their contents in domesticated soybean seeds are highly variable. Wild soybeans are known for higher seed isoflavone contents than cultivars. Here we used experimental and modelling approaches on wild soybean (W05) and cultivated soybean (C08) to delineate factors influencing isoflavone accumulation. We found imported nutrients were converted into storage compounds, with isoflavone accumulation in W05 seeds being faster than in C08 ones. The isoflavone accumulation during seed development was simulated using context-specific cotyledon metabolic models of four developmental stages on cultivar C08, and the metabolic burden imposed by increasing biomass was evaluated. Trade-off analyses between biomass and isoflavone suggest that high biomass requirement in cultivars could limit the reallocation of resources for secondary metabolite production. Isoflavone production in mature seeds was also influenced by biomass compositions. Seeds with higher carbohydrate contents favour isoflavone production, while those with highest protein and oil contents had lowest isoflavone contents. Although seeds could synthesize isoflavones on their own, the predicted fluxes from biosynthesis alone were lower than the empirical levels. Shadow price analyses indicated that isoflavone accumulation depended on both intrinsic biosynthesis and direct contribution from the plant.

The Ecological Strategy Determines the Response of Fungi to Stress: A Study of the 2,4-diacetylphloroglucinol Activity Against Aspergillus and Fusarium Species.

Aspergillus and Fusarium are two economically important genera of fungi. They cause significant yield losses and contamination of crops with mycotoxins. In this study we aimed to evaluate the impact of 2,4-diacetylphloroglucinol (2,4-DAPG) on Aspergillus and Fusarium fungi. It is hypothesized that two fungal genera, which have different ecological strategies, react differently to stress caused by a secondary metabolite produced by rhizosphere Pseudomonas species. We found that 2,4-DAPG was able to reduce biofilm formation of Aspergillus and Fusarium, as reflected in biomass and its chemical composition. Furthermore, subinhibitory concentrations of 2,4-DAPG increased the levels of ergosterol and polysaccharides (α- and β-glucans, chitin) in the cell membrane and cell wall of Aspergillus, while decreasing them in Fusarium. 2,4-DAPG altered the production of secondary metabolites, especially mycotoxins and extracellular proteases. The production of ochratoxin A was decreased in A. ochraceus, and T-2 toxin and zearalenone, on the contrary, were increased in F. culmorum and F. sporotrichioides, respectively. Thus, using 2,4-DAPG we demonstrated that the ecological role of fungi determines their reaction to antibiotic substances produced by the plant microbiome. Our data contributes to understanding the molecular mechanisms behind symbiotic relationships in natural communities, which are mediated by the biosynthesis of antibiotics.

Endophyte-based fungal elicitors for enhanced production of valepotriates and sesquiterpenoids in leaf cell suspension cultures of Valeriana jatamansi Jones.

The immense therapeutic value of Valeriana jatamansi is attributed to the presence of bioactive secondary metabolites (valepotriates and sesquiterpenoids). Its over-exploitation in wild habitats resulted in extensive depletion, necessitating alternative approaches to produce its therapeutic metabolites. This study sought to assess the ability of endophytes of V. jatamansi to boost the biosynthesis of secondary metabolites in the leaf-cell suspension (LCS) culture of V. jatamansi. A total of 11 fungal endophytes were isolated from the rhizomes of V. jatamansi. Isolated endophytes were found to belong to phylum Ascomycota, Basidiomycota, and Mucoromycota. Supplementation of extracts of endophyte Phaeosphaeriaceae sp. VRzFB, Mucor griseocyanus VRzFD, Penicillium raistrickii VRzFK, and Penicillium sajarovii VRzFL in the LCS culture of V. jatamansi increased the fresh cell biomass by 19.6-39.1% and dry cell biomass by 23.4-37.8%. Most of the endophytes' extract could increase the content of valepotriates (26.5-76.5% valtrate and 40.5-77.9% acevaltrate) and sesquiterpenoids (19.9-61.1% hydroxyl valerenic acid) in LCS culture. However, only two endophytes Irpex lacteus VRzFI and Fusarium oxysporum VRzFF could increase the sesquiterpenoids acetoxy valerenic acid (36.9-55.3%). In contrast, some endophytes' extracts caused negative or no significant effect on the cell biomass and targeted metabolites. Increased secondary metabolites were corroborated with increased expression of iridoid biosynthesis genes in LCS culture. Production of H2O2 and lipid peroxidation was also varied with different endophytes indicating the modulation of cellular oxidative stress due to endophyte elicitors. The results suggest the distinct effect of different fungal endophytes-extract on LCS culture, and endophytes can serve as biotic elicitors for increasing the secondary metabolite production in plant in-vitro systems.