Yield Of Secondary Metabolites Research Articles

Light emitting diodes optimisation for secondary metabolites production by Droseraceae plants

The most abundant active compound in Droseraceae is plumbagin, a naphthoquinone widely used for medical purposes due to its antimicrobial, antitussive, antimalarial and anticancer properties. In this work, we created a light-emitting diode (LED) based culture illumination setup as an alternative to fluorescent lamps traditionally used as a light source in plant in vitro cultures. The plants of Drosera binata and Drosera peltata cultured under LED illumination grew equally well and produced similar amounts of biologically active compounds as plants grown under fluorescent lamps. The plants were cultured on two media differing in mineral composition, sucrose content and pH. Secondary metabolites were extracted with ethanol from the plants after harvesting. The extracts were subjected to HPLC and microbiological analyses. We observed differences in morphology and secondary metabolism between plants of the same species grown on different media. However, we did not note significant changes in secondary metabolite yield under assessed lighting conditions. We propose LEDs as a more efficient, eco-friendly and economically reasonable source of light for big scale in vitro production of plumbagin in Drosera species than fluorescent lamps.

In vitro propagation and phyto-chemical assessment of Cymbidium aloifolium (L.) Sw.: An orchid of pharma-horticultural importance

Orchids are one of the most fascinating plant families amongst the flowering plants. Amongst the various orchid genus Cymbidiums figure out prominently. The present study focuses on the development of an efficient in vitro regeneration protocol for Cymbidium aloifolium, an epiphytic orchid with high commercial value. It also aims at analysing the important phytochemicals and antioxidant potential of in vitro and in vivo plants. The effects of MS basal media (half or full strength) and MS medium supplemented with BAP were studied for in vitro seed germination. Among different media, 1/2 MS medium resulted in in vitro seed germination, protocorm development and plantlets formation in the shortest duration. However, 6-Benzylaminopurine (BAP) played an important role during proliferation of protocorms or in vitro multiplication, thus resulted in maximum number of shoots (39), root length (6.10 cm) on MS medium with 1.0 mg/L BAP. Largest shoot length was observed on solid BM-2 medium. 90% of the plantlets survived in the potting mixture consisting of cocopeat, perlite and wood saw dust in a ratio of 1:1:1. Comparative phytochemical analysis revealed that in vitro regenerated plants showed a higher yield of secondary metabolites. This work will facilitate the utilization of orchid phyto-constituents for various pharmaceutical applications in the industries.

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.

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.

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.

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.

Enhanced ascomycin production in Streptomyces hygroscopicus var. ascomyceticus by employing polyhydroxybutyrate as an intracellular carbon reservoir and optimizing carbon addition

BackgroundAscomycin is a multifunctional antibiotic produced by Streptomyces hygroscopicus var. ascomyceticus. As a secondary metabolite, the production of ascomycin is often limited by the shortage of precursors during the late fermentation phase. Polyhydroxybutyrate is an intracellular polymer accumulated by prokaryotic microorganisms. Developing polyhydroxybutyrate as an intracellular carbon reservoir for precursor synthesis is of great significance to improve the yield of ascomycin.ResultsThe fermentation characteristics of the parent strain S. hygroscopicus var. ascomyceticus FS35 showed that the accumulation and decomposition of polyhydroxybutyrate was respectively correlated with cell growth and ascomycin production. The co-overexpression of the exogenous polyhydroxybutyrate synthesis gene phaC and native polyhydroxybutyrate decomposition gene fkbU increased both the biomass and ascomycin yield. Comparative transcriptional analysis showed that the storage of polyhydroxybutyrate during the exponential phase accelerated biosynthesis processes by stimulating the utilization of carbon sources, while the decomposition of polyhydroxybutyrate during the stationary phase increased the biosynthesis of ascomycin precursors by enhancing the metabolic flux through primary pathways. The comparative analysis of cofactor concentrations confirmed that the biosynthesis of polyhydroxybutyrate depended on the supply of NADH. At low sugar concentrations found in the late exponential phase, the optimization of carbon source addition further strengthened the polyhydroxybutyrate metabolism by increasing the total concentration of cofactors. Finally, in the fermentation medium with 22 g/L starch and 52 g/L dextrin, the ascomycin yield of the co-overexpression strain was increased to 626.30 mg/L, which was 2.11-fold higher than that of the parent strain in the initial medium (296.29 mg/L).ConclusionsHere we report for the first time that polyhydroxybutyrate metabolism is beneficial for cell growth and ascomycin production by acting as an intracellular carbon reservoir, stored as polymers when carbon sources are abundant and depolymerized into monomers for the biosynthesis of precursors when carbon sources are insufficient. The successful application of polyhydroxybutyrate in increasing the output of ascomycin provides a new strategy for improving the yields of other secondary metabolites.

Functional annotations of ESTs of Stevia rebaudiana involved in abiotic stress signaling through computational approach.

Stevia rebaudiana (Bertoni) is known as a natural sweetener plant to produced steviol glycosides. The steviol glycosides biosynthesis is limited in S. rebaudiana plants due to the alteration in the environmental circumstances such as drought, cold, salt and light. These environmental circumstances are a common side-effect in plants affecting the plant growth, metabolism and yield of secondary metabolites. Due to absence of complete genome annotations, the plant metabolites signaling is difficult in order to get the exact enzymatic flow to the product. In this article, we have analyzed the ESTs of S. rebaudiana and predicted their role in plant signaling in term of cis-regulatory elements, their biological function respect to abiotic stress. Further, the predicted abiotic stress responsive factors were also analyzed in order to predict the relevant genes or proteins function in comparison with the genome of Arabidopsis thaliana. Total 5,548 ESTs of stevia were retrieved from NCBI database. EST-contigs assembled from 5393 were 619 contigs and 2,894 singletons elements were identified by assembler program. Due to short expressed sequences related to singletons, it is excluded for further study. Further, retrieved ESTs were resulted in to 619 EST-contigs by using the clustering method. Out of 619, 15 contigs belongs to transcription factor families while 292 contigs, belongs to five enzyme classes. Out of 619 contigs, the 529 contigs showing the correct gene ontology in term of biological process (BP), molecular Functions (MF) and cellular component (CC). Further, these contigs were also screened for metabolic pathways analyses using KEG database. In this, 390 metabolic pathways and 67 involved for signal transduction were identified from 619 contigs. The co-expression analysis was revealed by gene investigators and STRING 10.0 with 0.40 correlations and 0.9 mutual connection. In projected PPI network, the recognized factors (WD40-like protein, MYB-HB like, AP2-EREBP, C2H2, Hap3/NF-YB, bHLH, C2C2-CO-like, CW-Zn, FHA-SMAD, Nin like, SBP3, TIFY, Tc-PD, Znf-B and bIP) belong to plant signaling and MAPK signaling pathways. These TFs introduce as a candidate genes responsive factors may lead to enhanced plant growth and metabolism by overexpression.

Serine/threonine Kinases Play Important Roles in Regulating Polyunsaturated Fatty Acid Biosynthesis in Synechocystis sp. PCC6803.

Serine/threonine kinases (STKs) play important roles in prokaryotic cellular functions such as growth, differentiation, and secondary metabolism. When the external environment changes, prokaryotes rely on signal transduction systems, including STKs that quickly sense these changes and alter gene expression to induce the appropriate metabolic changes. In this study, we examined the roles of the STK genes spkD and spkG in fatty acid biosynthesis in the unicellular cyanobacterium Synechocystis sp. PCC6803, using targeted gene knockout. The linoleic acid (C18: 2), γ-linolenic acid (C18: 3n6), α-linolenic acid (C18: 3n3), and stearidonic acid (C18: 4) levels were significantly lower in spkD and spkG gene knockout mutants than in the wild type at a culture temperature of 30°C and a light intensity of 40 μmol⋅m–2⋅s–1. The expression levels of fatty acid desaturases and STK genes differed between the spkD and spkG gene knockout mutants. These observations suggest that spkD and spkG may directly or indirectly affect the fatty acid composition in Synechocystis sp. PCC6803 by regulating the expression of fatty acid desaturases genes. Therefore, the STK genes spkD and spkG play important roles in polyunsaturated fatty acid biosynthesis in Synechocystis sp. PCC6803. These findings could facilitate the development of cyanobacteria germplasm resources that yield high levels of fatty acids. In addition, they provide a theoretical basis for the genetic engineering of cyanobacteria with improved yields of secondary metabolites and increased economic benefits.

Untargeted Metabolomic Analyses Reveal Chemical Complexity of Dioecious

Cannabis is a mostly dioecious multi-use flowering plant genus. Sexual dimorphism is an important characteristic in Cannabis-based commercial production systems, which has consequences for fibre, seed, and the yield of secondary metabolites, such as phytocannabinoid and terpenes for therapeutic uses. Beyond the obvious morphological differences between male and female plants, metabolic variation among dioecious flowers is largely undefined. Here, we report a pilot metabolomic study comparing staminate (male) and pistillate (female) unisexual flowers. Enrichment of the α-linolenic acid pathway and consensus evaluation of the jasmonic acid (JA) related compound 12-oxo-phytodienoicacid (OPDA) among differentially abundant metabolites suggests that oxylipin signalling is associated with secondary metabolism and sex expression in female flowers. Several putative phytocannabinoid-like compounds were observed to be upregulated in female flowers, but full identification was not possible due to the limitation of available databases. Targeted analysis of 14 phytocannabinoids using certified reference standards (cannabidiolic acid (CBDA), cannabidiol (CBD), Δ9-tetrahydrocannabinolic acid A (Δ9-THCAA), Δ9-tetrahydrocannabinol (Δ9-THC), cannabichromenic acid (CBCA), cannabichromene (CBC), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabinolic acid (CBNA), cannabinol (CBN), cannabidivarinic acid (CBDVA), cannabidivarin (CBDV), tetrahydrocannabivarinic acid (THCVA), and tetrahydrocannabivarin (THCV)) showed a higher total phytocannabinoid content in female flowers compared with the male flowers, as expected. In summary, the development of a phytocannabinoid-specific accurate-mass MSn fragmentation spectral library and gene pool representative metabolome has the potential to improve small molecule compound annotation and accelerate understanding of metabolic variation underlying phenotypic diversity in Cannabis.

<i>Cannabis sativa</i> L. Response to Narrow Bandwidth UV and the Combination of Blue and Red Light during the Final Stages of Flowering on Leaf Level Gas-Exchange Parameters, Secondary Metabolite Production, and Yield

Many modifications to growing environments and specific stress induction techniques exist which are supported by preliminary research to increase yield and/or concentration of secondary metabolites in Cannabis sativa L. One such technique is the modification of the spectral composition of light late in flowering-stage development. In this study, we evaluated the hypothesis that the addition of narrow bandwidth UV-A light and the combination of narrow bandwidth blue and red light, during the final two weeks of the flowering cycle affect the concentration of cannabinoids and terpenes, with no difference in harvest dry weight. Three treatments were used in this experimental design, 1) control-full spectrum illumination, 2) UV-A (~390 nm) at ~66 PPFD in addition to control lighting, and 3) blue (~450 nm) and red (~660 nm) at ~158 PPFD in addition to control lighting. Light treatments were initiated during the final two weeks of flowering to assess secondary metabolite concentration (cannabinoids and terpenes) and yield of three cannabis cultivars (Type I (Larry OG), Type II (Pootie Tang), and Type III (Super White)). With two of the three cultivars used in this study responding with enhanced production of THC our results support the potential beneficial effects of attributed light-mediated treatments on cannabinoid production. On the other hand, our results show contrasting trends for terpene production and yield of dry weight flower.

Antioxidant potential of crude extract, flavonoid-rich fractions, and a new compound from the seeds of Cordia dichotoma

The current study assessed the antioxidant activity of methanolic extract and different fractions of the seeds of Cordia dichotoma by 2,2-diphenyl-2-picrylhydrazyl hydrate method. Phytochemical screening of C. dichotoma seed extract was done using thin-layer chromatography technique and phytochemical methods. The percentage yield of secondary metabolites like alkaloids and saponins was also determined. The methanolic extract was subjected to isolation by Column Chromatography. Phytochemical screening revealed the presence of significant amounts of phenols and flavonoids in the extract. TLC analysis confirmed the presence of phytoconstituents with the application of derivatizing agents like aluminium chloride and anisaldehyde. Total phenolic and flavonoid contents obtained were 37.7 and 32.16% w/w, respectively. The crude seed extract of C. dichotoma showed inhibition at all concentrations in a dose-dependent manner. Maximum scavenging activity was exhibited by the methanolic extract with a low IC 50 value. A new compound named Cordioside was also isolated from the same extract. The phytochemical screening of the seed extract showed the presence of rich amounts of phenolic compounds and flavonoids, which may be acting as the key factors responsible for the antioxidant activity. The results revealed that methanolic extract and the aqueous fraction of C. dichotoma seed possess a significant antioxidant activity.

Foliar application of chitosan and nano-magnesium fertilizers influence on seed yield, oil content, photosynthetic pigments, antioxidant enzyme activities of sesame (Sesamum indicum L.) under water-limited conditions

Applying elicitors and nano-fertilizer has been recommended to enhance the growth and yield of secondary metabolites in herbs and medicinal plants under water-limited stress. However, less information is available on the effects of chitosan and nano-magnesium fertilizers on sesame seed yield, oil content, and physiological traits in the presence of nano-magnesium chelate (nano-Mg) under water-limited supply. In this regard, field experiments as a split-factorial experiment was performed based on randomized blocks in three replicates in Varamin city, south of Tehran, Iran, during 2015-2016 to evaluate the impact of chitosan and nano-Mg on physiological, seed, and oil traits of sesame. Irrigation cut-off based on BBCH scale was considered as the main factor including normal irrigation (I1), irrigation cut-off in 75 (I2), and 65 BBCH (I3) stages. Secondary factors as the subplot included ‘Oltan’ (C1) and ‘Dashtestan-2’ (C2) sesame cultivars, and foliar application of nano-Mg (application and non-application) and chitosan (control (CH1), foliar application of 4.8 g L-1 in 65 BBCH (CH2), and 6.4 g L-1 in 75 BBCH stages (CH3)). Further, free proline content, total sugars, the activity of antioxidant enzymes including catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1), and ascorbate peroxidase (APX, EC 1.11.1.11), photosynthetic pigments content, seed yield, and oil content were evaluated in the next stage. Based on the results, irrigation cut-off in 65 BBCH stage (flowering) significantly increased free proline content, total sugars, and the activity of antioxidant enzymes, CAT, POD, and APX. However, chlorophyll a, b, and total contents, seed yield, oil percentage, and yield decreased under water stress. ‘Dashtestan-2’ cultivar had the highest seed yield and oil content, and more tolerant cultivar under water-limited stress. Interestingly, the production of proline content and total sugars increased while the activity of antioxidant enzymes, CAT, POD, and APX decreased under application of nano-Mg and CH2, which influenced both sesame response and seed attributes. As a result, the production of some physiological traits in sesame cultivars may be regulated by adjusting the irrigating practices. Finally, the co-application of nano-Mg and CH2 increased the seed yield and oil content of sesame under limited water supply in the arid and semi-arid region.

Statistical Optimization of Parameters for Enhanced Bioactive Metabolites Produced by Streptomyces hygroscopicus AVS7

The modern technology focuses on developing a novel statistical approach for highest yield of bioactive microbial metabolites which contain therapeutic properties, eventually leading to a promising strategy for treating various diseases and disorders. In this research, we aimed to develop the optimization process for maximum yield of crude pigmented secondary metabolites (CPSM) from Streptomyces hygroscopicus AVS7 through statistical approaches and determine its antimicrobial activity. The isolate produced maximum of 2.92 g/L on 9th day in starch casein nitrate (SCN) medium, and employing the SCN medium as seed medium, the research has initiated one factor at a time (OFT) for screening the essential physical, physiological and biological parameters. The OFT-screened factors were further determined for their importance through Plackett–Burman (PB) design, and the PB results revealed the significant factors (sesame oil cake, KNO3, glycerol, glucose, casein and urea). The experimentation was carried to Box-Behnken (BB) design–RSM using significant factors for the evaluation of interaction between the factors influencing the highest yield of CPSM, and the model was validated. The maximum CPSM extract was yielded by culturing the S. hygroscopicus AVS7 in the optimized medium, and there was twofold increase in the yield of CPSM extract when compared to seed medium. This statistical approach is a low-cost and economical method to develop maximum CPSM for medicinal and industrial purposes. The produced CPSM was found to contain the antimicrobial properties. Further, the research leads to the in vitro and in vivo assessment of purified bioactive secondary metabolite.

Efficiency of Funneliformis mosseae and Thiobacillus sp. on the secondary metabolites (essential oil, seed oil and mucilage) of Lallemantia iberica under salinity stress

ABSTRACT Dragon’s head (Lallemantia iberica Fisch. & Mey), annual herb from the Lamiaceae family, is worldwide distributed. Lallemantia is a medicinal plant with a variety of uses, and all of its parts have economic applications, including leaves to extract essential oils, mucilage and oil for different purposes in food and medicine. This study evaluated the effects of inoculants (single and dual application of Funneliformis mosseae and/or Thiobacillus sp.) on the secondary metabolites of Lallemantia iberica under saline (6.72 dS/m) and non-saline conditions. The results indicated an increase in the percentage of essential and seed oils, along with a decrease in mucilage percentage and their yields under stress. Salinity increased the unsaturated fatty acids and unsaturated/saturated fatty acids, as well as the main components of the essential oil. However, the mucilage constituents were reduced by salt stress. Furthermore, mycorrhizal plants exhibited positively incremental effects on the components of secondary metabolites under salinity conditions. In some cases, the individual treatment of Thiobacillus had a greater effect on some fatty acids. In general, mycorrhiza and Thiobacillus can improve the yield and quality of secondary metabolites and thus compensate for the part of yield reduction in saline soil conditions.

Increased phenolic acid and tanshinone production and transcriptional responses of biosynthetic genes in hairy root cultures of Salvia przewalskii Maxim. treated with methyl jasmonate and salicylic acid.

The purpose of this study is to reveal the impact of the plant hormone salicylic acid (SA) and methyl jasmonate (MeJA) on the growth, effective components accumulation, and related gene expression of the hairy root of Salvia przewalskii Maxim. Various concentrations of SA (0, 25, 50, 100, 200μM) or MeJA (0, 50, 100, 200, 400, 600μM) were added to the culture medium of Salvia przewalskii Maxim. Low concentrations of SA promoted the growth of hairy root, while a high concentration inhibited it. 0 to 400μM MeJA promoted the growth of hairy root, but 600μM MeJA starts to inhibit its growth. 50μM SA and 400μM MeJA significantly enhanced the production of caffeic acid, rosmarinic acid, salvianolic acid B, cryptotanshinone, and tanshinone IIA. In general, 50μM SA can be used to accumulate of tanshinone in hairy roots of S. przewalskii with 6days. 400μM MeJA can be used to accumulate of phenolic acids in hairy roots of S. przewalskii with 3days. The selected genes in the tanshinone and phenolic acid biosynthetic pathway were upregulated with elicitation. To obtain a higher yield and content of secondary metabolites, it is advisable to use 50μM SA or 400μM MeJA as the optimal doses to cultivate the hairy root of S. przewalskii. This study provides, for the first time, an efficient tanshinone and phenolic acid production method for S. przewalskii.

Modifications to central carbon metabolism in an engineered Streptomyces host to enhance secondary metabolite production

To improve the production of secondary metabolites by alternation of the carbon metabolic flux, two types of deletion mutants of the central metabolic pathway, the Embden-Meyerhof (EM) or pentose phosphate (PP) pathway, in the genetically engineered Streptomyces avermitilis were constructed. Double-deletion mutants of phosphofructokinase (ΔpfkA1ΔpfkA3) in the EM pathway carrying a gene cluster for chloramphenicol biosynthesis markedly increased chloramphenicol production synthesized through the shikimate pathway. Although the ΔpfkA1ΔpfkA3 double-deletion mutant grew more slowly, its specific productivity of chloramphenicol (per dry cell weight) was 2.0-fold higher than that of the engineered S.avermitilis strain. However, the productivity of chloramphenicol was lower by the double-deletion mutant of transaldolase in the PP pathway, which supplies the precursor of the shikimate pathway. A carbon-flux analysis of the EM and PP pathways using [1-13C] glucose revealed that carbon flux in the ΔpfkA1ΔpfkA3 double-deletion mutant increased through the PP pathway, which enhanced the production of chloramphenicol. These results suggest that a metabolic modification approach has the potential to increase the titers and yields of valuable secondary metabolites.

Salicylic acid increases flavonolignans accumulation in the fruits of hydroponically cultured Silybum marianum

Silybum marianum (L.) Gaertn. (Asteraceae) was hydroponically cultured using a nutrient film technique system. Silibinin, isosilibinin and silychristin were detected in the fruits of the cultured plants. The effect of salicylic acid on the improvement of flavonolignans production by the fruits of the hydroponically cultured S. marianum was investigated. Salicylic acid was added to the nutrient solution at different concentrations (100, 200 and 400 µM) and the mature fruits of the plant were collected five days after elicitor addition. The fruits were then analyzed for their total flavonolignans contents and individual components using quantitative proton nuclear magnetic resonance spectroscopy (qHNMR) and high-performance liquid chromatography (HPLC). The results showed that elicitation with salicylic acid at 200 µM for five days increased production of total flavonolignans (1.7-fold by qHNMR and 1.6-fold by HPLC) higher than the control cultures and (1.4-fold by qHNMR and 1.1-fold by HPLC) higher than the cultivated plants. Silychristin was the major flavonolignan produced by the cultured plant. Elicitation by 200 µM salicylic acid increased silychristin production (1.6-fold by qHNMR and HPLC) higher than the control cultures and (1.3-fold by qHNMR and 1.0-fold by HPLC) higher than the cultivated plants. The present study provides a chance to improve secondary metabolite yield, serves as a useful tool for studying the biosynthesis of these medicinally valuable compounds and its regulation in plant and spots more light on hydroponic system as an important agricultural technique.