Secondary Metabolite Profiles Research Articles

Phytotoxicity of Dactylonectria spp. exudates on kiwifruit vine and profile of secondary metabolites for understanding their relationship with the host plant

Kiwifruit vine decline syndrome (KVDS), which is responsible for a progressive decline in yields in Italy, is linked to a non-specific reduction in root development, the biotic or abiotic causes of which are still unclear. Dactylonectria is one of the most common soil-borne fungi associated with kiwifruit vines, However, its role in KVDS has not yet been clarified; therefore, Dactylonectria functional relationship with kiwifruit vine at rhizosphere level was investigated focusing solely on its exudates. Six isolates, four from kiwifruit-bearing soils belonging to D. torresensis. D. ecuadoriensis, D. novozelandica and D. pauciseptata, and two D. torresensis from a virgin soil, was tested for phytotoxicity of exudates by growing kiwifruit in vitro plants on MS media amended at 50% with sterile fungal filtrates. Parallelly, low molecular weight (LMW) metabolic profile of fungal filtrates was evaluated with untargeted metabolomics approach using LC-MS/TOF. The fungal isolates from kiwifruit bearing soil were much richer in LMW metabolites than those from virgin soil. Non host specific mycotoxins such as Aflaxoxin B2, Alternariol and Alterlactone were found in these isolates along with a number of metabolites most of which were characterised by antimicrobial properties. D. torresensis isolates were clearly discriminated from the other three species based on metabolic profile. A negative Pearson correlation between the growth index of kiwifruit vitro-plants and LMW metabolite count per isolate (richness) showed that the latter were associated with phytotoxicity, but the degree of correlation (r = −0.639) indicated that they were not the only component responsible. The results suggest that kiwifruit vines may alter the composition of the Dactylonectria spp. community in the root zone, which in turn may directly or indirectly contribute to kiwifruit vine decline syndrome.

Selected cannabis cultivars modulate glial activation: in vitro and in vivo studies

IntroductionMultiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system characterized by neuroinflammation, demyelination and axonal loss. Cannabis, an immunomodulating agent, is known for its ability to treat MS effectively. However, due to variations in the profile of secondary metabolites, especially cannabinoids, among cannabis cultivars, the effectiveness of cannabis treatment can vary, with significant variability in the effects on different biological parameters. For screening available cultivars, cellular in vitro as well as pre-clinical in vivo assays, are required to evaluate the effectiveness of the wide range of chemical variability that exists in cannabis cultivars. This study evaluated comparatively three chemically diverse cannabis cultivars, CN2, CN4 and CN6, containing different ratios of phytocannabinoids, for their neuroinflammatory activity in MS model.Materials and methodsIn vitro experiments were performed with lipopolysaccharide (LPS)-activated BV-2 microglia and primary glial cells to evaluate the effect of different cannabis cultivars on nitric oxide (NO) and inflammatory cytokines, as well as inducible nitric oxide synthase (iNOS) protein expression. An in vivo experiment using the experimental autoimmune encephalomyelitis (EAE) MS model was conducted using Myelin oligodendrocyte glycoprotein (MOG) as the activating peptide. The cannabis extracts of the cultivars CN2, CN4, CN6 or vehicle, were intraperitoneally injected with clinical scores given based on observed symptoms over the course of study. At the end of the experiment, the mice were sacrificed, and splenocyte cytokine secretion was measured using ELISA. Lumbar sections from the spinal cord of treated MS mice were evaluated for microglia, astrocytes and CD4+ cells.ResultsExtracts of the CN2 cultivar contained tetrahydrocannabinolic acid (THCA) and tetrahydrocannabinol (THC) without cannabidiol (CBD), and a number of monoterpenes. CN4 contained cannabidiolic acid (CBDA) and tetrahydrocannabidiolic acid (THCA), with significant amounts of THC: CBD in a 1:1 ratio, as well as sesquiterpenes and some monoterpenes; and CN6 contained primarily CBDA and THCA, as well as THC and CBD in a 2:1 ratio, with some sesquiterpenes and no monoterpenes. All extracts were not cytotoxic in glial cells up to 50 µg/ml. Dose dependent inhibition of LPS-induced BV2 as well as primary microglial NO secretion confirmed the anti-inflammatory and anti-oxidative activity of the three cannabis cultivars. CN2 but not CN4 reduced both astrocytosis and microglial activation in lumbar sections of EAE mice. In contrast, CN4 but not CN2 significantly decreased the secretion of TNFα and Interferon γ (IFNγ) in primary splenocytes extracted from EAE mice.ConclusionsWhile both cannabis cultivars, CN2 and CN4, significantly reduced the severity of the clinical signs throughout the course of the study, they modulated different inflammatory mediators and pathways, probably due to differences in their phytocannabinoid composition. This demonstrates the differential potential of cannabis cultivars differing in chemotype to regulate neuroinflammation and their potential to treat MS.

Biodiversity of ochratoxigenic Aspergillus species isolated from çavuş and karalahna grapes in Bozcaada, Türkiye

This study reported the presence and OTA production of ochratoxigenic Aspergillus species isolated from Bozcaada Çavuş and Karalahna grapes. The study was conducted with Aspergillus isolates isolated from grape samples collected during ripening in 2015 and 2016. Thin-layer chromatography was used to determine the secondary metabolite profiles of 290 Aspergillus isolates. Out of these, 122 isolates were found to be possible OTA producers. 43 isolates, selected based on their colony morphology of 122 isolates in different culture media, were identified using calmodulin gene sequencing analysis. The identified isolates were determined to be A. tubingensis, A. carbonarius, A. niger/welwitschia/awamori, A. welwitschia, A. spelaeus, and A. fructus. OTA production was investigated in six isolates. Using HPLC-FLD, these isolates were found to produce OTA in quantities ranging from 3.550 ± 0.240 to 92.346 ± 0.818 ppb. Consequently, OTA-producing Aspergillus species were isolated from grapes. The presence of A. spelaeus and A. fructus was reported for the first time in grapes. A. fructus has been found to be a new record for Türkiye.

Mass spectrometry and Nuclear magnetic resonance spectroscopy profiles of red and pink Rhododendron flower petals establish them as rich sources of bioactive secondary metabolites

AbstractRhododendron petals are considered high‐value owing to their commercial utility, national/state flower status in certain countries, and bioactive potential from recent studies. Profiling and quantitative analysis of the bioactive metabolites would evaluate if they can be natural sources. This study is focused on the comprehensive profiling of secondary metabolites in the hot aqueous petal extracts of Red and Pink Rhododendron flowers (Rhododendron arboreum and Rhododendron campanulatum) using separation and fragmentation patterns from mass spectrometry (MS) (gas chromatography‐MS and liquid chromatography‐tandem MS) and chemical shifts from proton‐nuclear magnetic resonance spectroscopy. The complementary analytical platforms highlighted the petals to be rich in promising bioactive molecules such as quinic acid, chlorogenic acid (caffeoyl quinic acid), protocatechuic acid, coumaroyl quinic acids, catechin, epigallocatechin, and shikimic acid. The analysis also reflected the activity of shikimic acid, phenolic acid, and flavonoid biosynthetic pathways in Rhododendron flowers. These metabolites are well reported for their bioactive potential as anti‐oxidative, anti‐viral, anti‐cancerous, anti‐diabetic, anti‐inflammatory, etc. While the quantitative and multivariate analysis showed variations in the levels of phenolic acids and flavonoids, it is established that red and pink Rhododendron flower petals are a rich source of bioactive phytochemicals of interest to the phytochemical Industry.

Secondary metabolite profiling using HR-LCMS, antioxidant and anticancer activity of Bacillus cereus PSMS6 methanolic extract: In silico and in vitro study

Novel anticancer drugs of natural origin have increased tremendously due to the resistance of multiple chemotherapeutic drugs in breast cancer therapy and their high toxicity with undesirable side effects. The study investigates the bioactivity of secondary metabolites derived from Bacillus cereus PSMS6 isolated from marine soil sediment in the Velar estuary, Parangepattai, Cuddalore district, Tamil Nadu, and India. Strains were isolated and antagonistic activity was screened using the agar well diffusion method. B. cereus PSMS6 exhibited potency, and its crude extract was tested for antioxidant, anticancer, and cytotoxic MTT assay potential. The methanolic extract of B. cereus PSMS6 was analyzed by mass spectrometry HRLC-MS and FT-IR to determine the bioactive compounds. A drug interaction study with the anti-breast cancer protein HER2 was performed by molecular docking analysis. Antioxidant activities were determined using total antioxidant scavenging assay, ABTS and DPPH free radical scavenging assays. The total antioxidant scavenging assay of the crude extract of B. cereus methanol had an IC50 value of 28.33±1.01, in ABTS IC50 value of the extract was 29.00±0.28 and in DPPH the IC50 of the extract was 34.91±0.09. The negative ion compound Palmitoylglycerone phosphate had a LibDock score of 149.487 and the positive ion compound N5-(4-Methoxybenzyl) glutamine had 120.116. These compounds show promising anticancer activity. The current study reported that the bioactive secondary metabolite of B. cereus PSMS6 retains anti-cancer, and antioxidant properties. This is the first report to show the production of the Palmitoylglycerone phosphate metabolite from B. cereus PSMS6.

GC/MS chemical profiling and isolation of secondary metabolites from Leontice ewersmannii

GC/MS chemical profiling of the aerial parts of Leontice ewersmannii revealed the presence of various bioactive compounds of which 20 compounds were in n-hexane fraction and 3 compounds in basic DCM fraction. Among the identified compounds alkaloids, fatty acids and their esters, fatty alcohols, hydrocarbons, and sterol were detected. Phytochemical investigation of the aerial parts of L. ewersmannii led to isolation of 17 compounds including 1-heptacosanol (1), phytol (2), lupenone (3), palmitic acid (4), oleic acid (5), stigmasterol (6), stigmast-7-en-3-ol (7), methyl palmitate (8), methyl linoleate (9), butyl palmitate (10), butyl linoleate (11), dimethyl dodecanedioate (12), methyl cerebronate (13), β-sitosterol (14), β-sitosterol 3-O-β-glucopyranoside (15), sophoridine (16) and camoensine (17). The structures of the isolated compounds were determined by 1D NMR, HR-ESI-MS, and GC-MS. All methyl esters of fatty acids are possible artifacts during extraction. Additionally, the antimicrobial activity of the total extract and different fractions was screened, and they exhibited no inhibition of the growth at the tested concentration ranging from 8 to 200 μg/mL.

Calafate (Berberis microphylla G. Forst) Populations from Chilean Patagonia Exhibit Similar Structuring at the Genetic and Metabolic Levels

Berberis microphylla, commonly known as calafate, is one of the most promising species of Chilean Patagonia to be domesticated, due to its anthocyanin-rich berries. The main aim of this study was to understand the genetic structure of the wild populations of B. microphylla in the main regions where it grows and its relationship with phenolic secondary metabolite profiles. Ripe berry samples and leaves were collected from the Aysén and Magallanes regions. Genetic analyses were carried out using 18 microsatellite markers. Phenolic compounds were extracted from the ripe fruits and were quantified using high-performance liquid chromatography (HPLC). Their antioxidant capacity was determined according to the Trolox equivalent antioxidant capacity (TEAC) assay. Total phenols were measured as their absorbance at a wavelength of 280 nm. Both the genetic and chemometric data were explored using unsupervised and supervised methods. The genetic markers suggest the existence of three groups, two of them corresponding to the Aysén and Magallanes samples, and the third corresponding to Chile Chico (a district in Aysén), which was the most divergent of the three. Similar results were observed in the phenolic profile obtained with chemometric analysis, with the same samples forming a separate third group. The differentiation achieved using the genetic and chemical data may be the result of intrinsic genetic differences, environmental effects on fruit maturity, or the sum of both factors. These are all points to consider in the domestication of this valuable species by selecting individuals with desirable traits and contrasting phenotypes.

Secondary Metabolite Profile in Mature and Old Leaves of Four Piper Species: Forest Betel (Piper aduncum L.), Red Betel (Piper crocatum Ruiz & Pav.), Javanese Chili Betel (Piper retrofractum Vahl.), and Green Betel (Piper betle L.)

Piper species is a potential medicinal plant, empirically known for its effectiveness in curing various diseases, particularly in Indonesia. Therefore, this research aimed to evaluate the similarities and differences in the profile of secondary metabolite compounds in mature and old leaves of four Piper species using Gas Chromatography-Mass Spectrometry (GC-MS). The analysis was also carried out to identify the specific compounds found in each species at different leaf development stages. Samples used were mature and old leaves from four species of Piper, namely forest betel (Piper aduncum L.) (PA), red betel (Piper crocatum Ruiz & Pav.) (PC), Javanese chili betel (Piper retrofractum Vahl.) (PR), and green betel (Piper betle L.) (PB). Subsequently, samples were extracted using ethanol solvent and secondary metabolite profile was detected through GC-MS. A total of 40 secondary metabolite compounds were found in mature and old leaves of four species. The results showed that alkaloid content contributed 25% of the total compounds detected, while fatty acids yielded the largest portion (27.5%). Based on PCA score plot analysis, a significant grouping of secondary metabolite compounds was observed in all species, where PC was categorized separately on the right, and the other species were on the left. Several specific compounds were also found only in one species and not in others. Similar to mature and old leaves, some compounds were discovered in one of the developmental phases. Dillapiole and hexadecane were only found in PA, both in mature and old leaves; germacrene A, eugenol, and chavicol were found in mature and old leaves of PB, but beta-selinene, delta-guaiene, and linolelaidic acid were only found in mature leaves. In PC, there were specific compounds namely benzofuran, myrcene, and 1,6,10-dodecatrien that were found in mature and old leaves. Besides that, trans-ocimene and alpha-bisabolol were only found in old leaves of PC. In PR, only tetracosane was found in mature leaves, while piperidine, octanodecanoic acid, and benzylmalonic acid were found in old leaves.

Responses to lead stress in Scrophularia striata: insights into antioxidative defence mechanisms and changes in flavonoids profile.

Lead (Pb) induces oxidative stress in plants, which results in different responses, including the production of antioxidants and changes in the profile of secondary metabolites. In this study, the responses of Scrophularia striata exposed to 250mgL-1 Pb (NO3 )2 in a hydroponic environment were determined. Growth parameters, oxidative and antioxidative responses, redox status, and the concentration of Pb were analysed in roots and shoots. Malondialdehyde and hydrogen peroxide (H2 O2 ) levels in the roots were significantly increased and reached their highest value at 72h after Pb treatment. Superoxide dismutase, catalase, and peroxidase, as an enzymatic antioxidant system, were responsible for reactive oxygen species scavenging, where their activities were increased in the shoot and root of Pb-treated plants. Enzymatic antioxidant activities were probably not enough to remove a significant H2 O2 content in response to Pb treatment. Therefore, other defence responses were activated. The results stated that the flavonoid components of S. striata progressed towards the increase of isoflavone, flavanol, and stilbenoid contents under Pb treatment. In general, S. striata stimulates the enzymatic defence system and activates the non-enzymatic system by modulating the profile of flavonoids toward the production of flavonoids with high antioxidant activity, such as quercetin and myricetin in response to Pb stress.

Secondary metabolite profiling of Pseudomonas aeruginosa isolates reveals rare genomic traits.

Pseudomonas aeruginosa is a ubiquitous Gram-negative opportunistic pathogen with remarkable phylogenetic and phenotypic variabilities. In this work, we applied classical molecular networking analysis to secondary metabolite profiling data from seven Pseudomonas aeruginosa strains, including five clinical isolates from the lung secretions of people with cystic fibrosis (CF). We provide three vignettes illustrating how secondary metabolite profiling aids in the identification of rare genomics traits in P. aeruginosa. First, we describe the identification of a previously unreported class of acyl putrescines produced by isolate mFLRO1. Secondary analysis of publicly available metabolomics data revealed that acyl putrescines are produced by <5% of P. aeruginosa strains. Second, we show that isolate SH3A does not produce di-rhamnolipids. Whole-genome sequencing and comparative genomics revealed that SH3A cannot produce di-rhamnolipids because its genome belongs to clade 5 of the P. aeruginosa phylogenetic tree. Previous phylogenetic analysis of thousands of P. aeruginosa strains concluded that <1% of publicly available genome sequences contribute to this clade. Last, we show that isolate SH1B does not produce the phenazine pyocyanin or rhamnolipids because it has a one-base insertion frameshift mutation (678insC) in the gene rhlR, which disrupts rhl-driven quorum sensing. Secondary analysis of the tens of thousands of publicly available genomes in the National Center for Biotechnology Information (NCBI) and the Pseudomonas Genome Database revealed that this mutation was present in only four P. aeruginosa genomes. Taken together, this study highlights that secondary metabolite profiling combined with genomic analysis can identify rare genetic traits of P. aeruginosa isolates.IMPORTANCESecondary metabolite profiling of five Pseudomonas aeruginosa isolates from cystic fibrosis sputum captured three traits present in <1%-5% of publicly available data, pointing to how our current library of P. aeruginosa strains may not represent the diversity within this species or the genetic variance that occurs in the CF lung.

Rhizobium symbiosis improves amino acid and secondary metabolite biosynthesis of tungsten-stressed soybean (Glycine max).

The industrially important transition metal tungsten (W) shares certain chemical properties with the essential plant micronutrient molybdenum and inhibits the activity of molybdoenzymes such as nitrate reductase, impacting plant growth. Furthermore, tungsten appears to interfere with metabolic processes on a much wider scale and to trigger common heavy metal stress response mechanisms. We have previously found evidence that the tungsten stress response of soybeans (Glycine max) grown with symbiotically associated N2-fixing rhizobia (Bradyrhizobium japonicum) differs from that observed in nitrogen-fertilized soy plants. This study aimed to investigate how association with symbiotic rhizobia affects the primary and secondary metabolite profiles of tungsten-stressed soybean and whether changes in metabolite composition enhance the plant's resilience to tungsten. This comprehensive metabolomic and proteomic study presents further evidence that the tungsten-stress response of soybean plants is shaped by associated rhizobia. Symbiotically grown plants (N fix) were able to significantly increase the synthesis of an array of protective compounds such as phenols, polyamines, gluconic acid, and amino acids such as proline. This resulted in a higher antioxidant capacity, reduced root-to-shoot translocation of tungsten, and, potentially, also enhanced resilience of N fix plants compared to non-symbiotic counterparts (N fed). Taken together, our study revealed a symbiosis-specific metabolic readjustment in tungsten-stressed soybean plants and contributed to a deeper understanding of the mechanisms involved in the rhizobium-induced systemic resistance in response to heavy metals.

Integrated Full-Length Transcriptomics and Metabolomics Reveal Glycosyltransferase Involved in the Biosynthesis of Flavonol Glycosides in Laportea bulbifera.

Many species of the Urticaceae family are important cultivated fiber plants that are known for their economic and industrial values. However, their secondary metabolite profiles and associated biosynthetic mechanisms have not been well-studied. Using Laportea bulbifera as a model, we conducted widely targeted metabolomics, which revealed 523 secondary metabolites, including a unique accumulation of flavonol glycosides in bulblet. Through full-length transcriptomic and RNA-seq analyses, the related genes in the flavonoid biosynthesis pathway were identified. Finally, weighted gene correlation network analysis and functional characterization revealed four LbUGTs, including LbUGT78AE1, LbUGT72CT1, LbUGT71BX1, and LbUGT71BX2, can catalyze the glycosylation of flavonol aglycones (kaempferol, myricetin, gossypetin, and quercetagetin) using UDP-Gal and UDP-Glu as the sugar donors. LbUGT78AE1 and LbUGT72CT1 showed substrate promiscuity, whereas LbUGT71BX1 and LbUGT71BX2 exhibited different substrate and sugar donor selectivity. These results provide a genetic resource for studying Laportea in the Urticaceae family, as well as key enzymes responsible for the metabolism of valuable flavonoid glycosides.

Analysis of Mycotoxins and Cytotoxicity of Airborne Molds Isolated from the Zoological Garden-Screening Research.

The objective of this paper was to assess the airborne mold contamination, secondary metabolite profiles, and cytotoxicity of the dominant fungal species isolated from the air in selected rooms at a Zoological Garden. Fungal concentrations were measured with MAS-100 air samplers. The collected airborne fungi were identified using a combination of morphological and molecular methods. The cytotoxicity of 84 strains belonging to two Penicillium and Aspergillus genera was determined using the quantitative colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium salt) assay. The mycotoxins were detected using high-performance liquid chromatography (HPLC) with a mass spectrometry detector. The ITS gene was amplified and sequenced to identify the 132 species. For mycotoxicological and cytotoxicity analyses, 52 Penicillium isolates and 32 Aspergillus representatives were selected. Cytotoxicity was confirmed in 97.6% of cases analyzed. Using the LC-MS/MS method, 42 out of 84 strains produced at least one of the following toxins: ochratoxin A, ochratoxin B, patulin, gliotoxin, roquefortine C, griseofulvin, sterigmatocystin, fumonisin B2, moniliformin, and mycophenolic acid. Analytical methods for assessing the presence of mycotoxins in fungal isolates collected directly from the air have proven to be an effective tool. Our research provides new information on the occurrence of potentially toxin-producing molds within a zoo.

First description of adenosine production by Gnomoniopsis smithogilvyi, causal agent of chestnut brown rot

Gnomoniopsis smithogilvyi (Gnomoniaceae, Diaporthales) is the main causal agent of chestnut brown rot on sweet chestnut worldwide. The rotting of nuts leads to alterations in the organoleptic qualities and decreased fruit production, resulting in significant economic losses. In 2021, there was an important outbreak of chestnut rot in southern Galicia (Spanish northwest). The profile of secondary metabolites from G. smithogilvyi was studied, especially to determine its capability for producing mycotoxins, as happens with other rotting fungi, due to the possible consequences on the safety of chestnut consumption. Secondary metabolites produced by isolates of G. smithogilvyi growing in potato dextrose agar (PDA) medium were identified using liquid chromatography coupled with high-resolution mass spectrometry. Three metabolites with interesting pharmacological and phyto-toxicological properties were identified based on their exact mass and fragmentation patterns, namely adenosine, oxasetin, and phytosphingosine. The capacity of G. smithogilvyi to produce adenosine in PDA cultures was assessed, finding concentrations ranging from 176 to 834 µg/kg. Similarly, the production of mycotoxins was ruled out, indicating that the consumption of chestnuts with necrotic lesions does not pose a health risk to the consumer in terms of mycotoxins.

LC/MS/MS and GC/MS/MS metabolic profiling of Leontodon hispidulus, in vitro and in silico anticancer activity evaluation targeting hexokinase 2 enzyme

Leontodon hispidulus Boiss is a wild annual plant growing in Egypt. The present study aims for the first time, to evaluate the phytochemical profile of the main secondary metabolites of the optimized ethanolic extract of the plant using Quadrupole Time-of-Flight Liquid chromatography-mass spectrometry and Gas chromatography-mass spectrometry. It also aims to assess the anticancer activity of its different fractions against the prostate carcinoma cell line. Moreover, an in-silico docking study was performed using the Hexokinase-two enzyme. LC-qToF-MS analysis revealed the tentative identification of 36 phenolic compounds including the glycosides of (luteolin, quercetin, kaempferol, apigenin, isorhamnetin, and daidzein), coumarines (esculin, esculetin, and daphnetin), and phenolic acids (chlorogenic, caffeic, quinic, P-coumaric, and rosmarinic). GC–MS/MS analysis revealed the presence of 18 compounds where palmitic acid, myristic acid, alpha-amyrin, and beta-amyrin were the major ones. The cytotoxic activity results revealed that methylene chloride and ethyl acetate fractions showed the highest cytotoxic activity against the PC3 cell line, with IC50 values of 19, and 19.6 μg/ml, respectively. Interestingly, the docking study demonstrated that apigenin-7-O-glucoside, luteolin-7-O-glucoside, kaempferol-3-O-glucuronide, quercetin-4′-O-glucoside, esculin, rosmarinic acid, chlorogenic acid, and α-amyrin exhibited high affinity to the selected target, HEK-2 enzyme.

Accumulation mechanism of metabolite markers identified by machine learning between Qingyuan and Xiushui counties in Polygonatum cyrtonema Hua

Polygonatum cyrtonema Hua is a traditional Chinese medicinal plant acclaimed for its therapeutic potential in diabetes and various chronic diseases. Its rhizomes are the main functional parts rich in secondary metabolites, such as flavonoids and saponins. But their quality varies by region, posing challenges for industrial and medicinal application of P. cyrtonema. In this study, 482 metabolites were identified in P. cyrtonema rhizome from Qingyuan and Xiushui counties. Cluster analysis showed that samples between these two regions had distinct secondary metabolite profiles. Machine learning methods, specifically support vector machine-recursive feature elimination and random forest, were utilized to further identify metabolite markers including flavonoids, phenolic acids, and lignans. Comparative transcriptomics and weighted gene co-expression analysis were performed to uncover potential candidate genes including CHI, UGT1, and PcOMT10/11/12/13 associated with these compounds. Functional assays using tobacco transient expression system revealed that PcOMT10/11/12/13 indeed impacted metabolic fluxes of the phenylpropanoid pathway and phenylpropanoid-related metabolites such as chrysoeriol-6,8-di-C-glucoside, syringaresinol-4'-O-glucopyranosid, and 1-O-Sinapoyl-D-glucose. These findings identified metabolite markers between these two regions and provided valuable genetic insights for engineering the biosynthesis of these compounds.

Phylogenetic, metabolic and pathogenic characteristics of Alternaria alternata strains from wheat in China

AbstractAlternaria is an important toxigenic fungal genus endangering the quality of cereal grains. No data are available in the literature regarding the composition of Alternaria species in wheat from the main wheat‐cultivating regions of China. In this study, a total of 282 strains were isolated from wheat kernels collected in various provinces. Phylogenetic characterization was performed using two informative loci, ASA10 and ASA19, demonstrating that all strains belonged to A. alternata. A low molecular diversity was observed, which did not appear to be influenced by geographic origin. The secondary metabolite profile of the strains was evaluated in rice culture. Altertoxin I was synthesized at a high concentration by the majority of the strains, while the accumulation of altenuene was lower in both frequency and level than that of alternariol and its derivative. A. alternata did not cause readily observable symptoms on wheat spikes after spraying of the conidia at anthesis, but a higher quantity of altertoxin I and Alternaria DNA were detected in inoculated grains. Artificial inoculations of apple fruit showed that all examined strains were capable of causing typical rot symptoms and producing all four toxins to a certain degree. The widespread occurrence of A. alternata on wheat grains and its ability to synthesize various toxic metabolites may pose a serious hazard for both growers and consumers.

A comparative study of secondary metabolites profiling and biological activity of Smyrnium olusatrum L. leaf, flower and fruit

Essential oil (EO) composition of Smyrnium olusatrum was characterised by high proportion of furanosesquiterpenes (51.66–69.35%). The leaf methanolic extract composition was found to be rich with Quercetin-O-hexoside (39.78%). Apigenin 6,8-di-Chexoside represent the major component of flower (18.2%) and fruits (18.82%). Flower extract exhibited the highest contents of total phenolic (48.97 mg GAE/g) and flavonoid (52.63 mg RE/g). The β-carotene and lycopene contents were in the order of 4.55-26.14 mg/100g, and 8.00-49.45 mg/100g, respectively. Methanolic extracts and EOs of different organs were found to possess antioxidant activities, as determined by scavenging effect, chelating activity and β-carotene-linoleic acid model system. Furthermore, Fruit S. olusatrum EO exhibited a potent inhibitory activity against Acetylcholinesterase, while the methanolic extract showed a weaker activity. The methanolic extract displayed inhibitory effects on α-amylase, whereas the EOs was not as efficient in inhibiting this enzyme. The observed level of biological activities varied depending on the specific extracts and organs studied.

Biochemical Analysis and Characterization of Silver Nanoparticles Synthesized by the Endophytic Fungus Plectosphaerella oligotrophica S8A26 Associated with Anaphalis contorta

Endophytic fungi associated with medicinal plants produce compounds that have vast biological activities. Anaphalis contorta is a highly therapeutic plant that has been used in traditional medicine by various communities. In the present study, the endophytic fungus Plectosphaerella oligotrophica S8A26 was isolated from the stem part of A. contorta and assessed for its plant growth promotion abilities, and showed positive results for phosphate solubilization and ammonia production. The secondary metabolites were analyzed for the presence of seven biochemicals, which indicate the presence of flavonoids, phenols, saponins, and steroids. The total flavonoid content and total phenolic content were recorded to be 25.67 µg of QE/mg of EE and 5.06 µg of GAE/mg of EE, respectively. The isolate was allowed to synthesize silver nanoparticles and characterized using X-ray diffraction, Energy Dispersive X-ray, Particle size distribution, and Zeta potential. XRD analysis has shown the AgNPs are crystalline with an average size of 24.81 nm. EDX study reveals silver as the main component with 48.63%. Particle size distribution indicates that the majority of the particles occur in the size range of 65–70 nm. Zeta potential value of −31.8 mV shows that the AgNPs are stable. Studies like the biological activities of the endophyte as well as AgNPs, secondary metabolite profiling, and the isolation of bioactive compounds would constitute important future research.

Phytochemical profile of secondary metabolites in the phloem of mature Pinus pinaster trees attacked by the pine wood nematode

The present study highlights, for the first time, the chemical composition of secondary metabolites (lipophilic and hydrophilic compounds) present in the phloem tissues of infected mature Pinus pinaster Ait. trees (on average 74 years old), which may be potentially determinant in the development of the pine wood nematode (PWN) Bursaphelenchus xylophilus. The levels of secondary metabolites in the phloem of infected trees were fairly constant along the height of the trees (an average of 30% dry phloem), but slightly lower compared with total extractives content in the phloem of mature healthy P. pinaster trees (30.0 vs. 39.9%). The hydrophilic fraction represented 91% of the total soluble compounds (27.3% of phloem mass) and it was mainly composed of phenolic compounds and reducing sugars (44.8% and 58.8% of the ethanol-water extracts). The lipophilic fraction (2.7% of phloem mass), was dominated by tricyclic diterpenic compounds (54.2–63.2% of the total lipophilic extracts) and fatty acids. Differences in the relative concentrations of individual compounds were observed compared to healthy pines, suggesting a response to the biotic stress imposed by nematode damage by an increased content of diterpenic resin acids, specifically dehydroabietic and abietic acids, and of total unsaturated fatty acids with a predominance of 9-octadecenoic acid.