Secondary Metabolite Profiles Research Articles

Silver nanoparticles affect phenolic and phytoalexin composition of Arabidopsis thaliana.

Silver nanoparticles are widely used in industry, medicine, biotechnology and agriculture. As a consequence, these nanoparticles are reaching the environment as waste products, which might have a negative impact on the environment, especially on plants. This includes the elicitation of various biochemical processes in plants. In this article, we report on the changes in secondary metabolic profile of Arabidopsis thaliana seedlings subjected to silver nanoparticle treatment in vitro. Briefly, various sizes (10nm, 40nm and 100nm in diameter) and concentrations (0.5-5.0ppm) of silver nanoparticles were tested. Ultraperformance liquid chromatography coupled with ultraviolet and fluorescence detectors as well as hyphenated to a high-resolution mass spectrometer (UPLC-PDA-FLR, UPLC-HESI-HRMS) and HPLC - ion trap mass spectrometer (HPLC-ESI-MS/MS), were applied to identify and quantify secondary metabolites. To understand whether silver ions could induce changes in the secondary metabolite profile, seedlings treated with silver nitrate in concentrations equivalent to these of nanoparticles were also analysed. The results showed significant differences in the accumulation of phenolic and indole compounds between treatments. Silver nanoparticles and silver ions induced the biosynthesis of camalexin, hydroxycamalexin O-hexoside and hydroxycamalexin malonyl-hexoside. These compounds are important phytoalexins for Brassicaceae family (especially for Camelinae clad) and are also synthetized in response to biotic and abiotic stresses. Statistically significant changes have been also observed for five phenolic compounds and 5'Glucosyl-dihydroneoascorbigen in different treatment conditions.

Impact of Paraburkholderia phytofirmans PsJN on Grapevine Phenolic Metabolism.

Phenolic compounds are implied in plant-microorganisms interaction and may be induced in response to plant growth-promoting rhizobacteria (PGPRs). Among PGPR, the beneficial bacterium Paraburkholderia phytofirmans PsJN was previously described to stimulate the growth of plants and to induce a better adaptation to both abiotic and biotic stresses. This study aimed to investigate the impact of PsJN on grapevine secondary metabolism. For this purpose, gene expression (qRT-PCR) and profiling of plant secondary metabolites (UHPLC-UV/DAD-MS QTOF) from both grapevine root and leaves were compared between non-bacterized and PsJN-bacterized grapevine plantlets. Our results showed that PsJN induced locally (roots) and systemically (leaves) an overexpression of PAL and STS and specifically in leaves the overexpression of all the genes implied in phenylpropanoid and flavonoid pathways. Moreover, the metabolomic approach revealed that relative amounts of 32 and 17 compounds in roots and leaves, respectively, were significantly modified by PsJN. Once identified to be accumulated in response to PsJN by the metabolomic approach, antifungal properties of purified molecules were validated in vitro for their antifungal effect on Botrytis cinerea spore germination. Taking together, our findings on the impact of PsJN on phenolic metabolism allowed us to identify a supplementary biocontrol mechanism developed by this PGPR to induce plant resistance against pathogens.

Effect of UV C irradiation on secondary metabolites profile and antioxidant activity of germinated brown rice

This study aims to investigate the effect of UV C irradiation on the secondary metabolites profile and the antioxidant activity of brown rice during two days germination. The change on the metabolite profile was identified using UPLC-ESI-QTOF, while antioxidant activity was performed using DPPH assay. The UPLC-ESI-QTOF chromatogram showed that three new peaks were found only in the germinated brown rice (GBR) that was irradiated by UV C. Based on the mass spectroscopy data, one of those three compounds was tentatively identified as glycosylated flavonoid, while the rest remained undetermined. The antioxidant activity of brown rice increased after two days germination, whilst there were no differences between antioxidant activities of germinated brown rice with UV C irradiation and that of without UV C irradiation.

Secondary metabolites profile and physiological leaf traits in wild and cultivated Corylus avellana under different nutritional status

Leaf secondary metabolites production and physiological leaf traits were analyzed in Corylus avellana wild type (WT) and cultivar (cv. ‘Tonda Gentile Trilobata’, TGT) under different nutrient supplies. Three treatments were applied: control treatment with no fertilizer supply (WT C and TGT C ), low nutrient treatment (WT LN and TGT LN ) and high nutrient treatment (WT HN and TGT HN ). The analysis of leaf extracts showed a higher concentration of Quercitrin and Myricitrin, with the highest concentrations of both the compounds in WT than TGT. This result can be related to the ecological role of flavonoids, including also antimicrobial properties, which resulted more useful in the understory forest form which hazelnut wild type originates. Therefore, their lower concentration in TGT can be relate to the genetic background of TGT cultivar with a lesser intrinsic need to produce such compounds and justified by a usual growth under more controlled environmental conditions, including also pest and disease control.

Evaluation of the role of Rhizobacteria in controlling root knot nematode (RKN) infection in Lycopersicon esculentum plants by modulation in the secondary metabolite profiles

Abstract Environmental stress imposes negative impacts on the growth and development of the crop plants. The present study was designed to assess the effect of PGPR (Pseudomonas aeruginosa and Burkholderia gladioli) on plant pigments and phenolic compounds in 10-days-old root knot nematode (RKN)-infected Lycopersiconesculentum seedlings. The levels of different osmoprotectants and organic acids were also evaluated in nematode-infected L. esculentum seedlings. Our results revealed that nematode-infected seedlings had reduced levels of plant pigments(chlorophyll (70.5%), carotenoids (64.8%), and xanthophylls (34.3%)) and enhanced levels of phenolic compounds(total phenols (40.3%), flavonoids (80.9%), anthocyanins (28.9%), and polyphenols (366.1%)), osmoprotectants(total osmolytes (15.3%), total carbohydrates (54.9%), reducing sugars (45.3%), trehalose (94.5%), glycine betaine (59.01%) and proline (69.6%) and (citric acid (28.4%), fumaric acid (18.16%), succinic acid (179.9%), and malic acid (21.7%)). The levels of these metabolites increased after inoculation with P. aeruginosa and B. gladioli. The expression of genes encoding different enzymes pertaining to phenols and organic acid metabolism were also studied. The expression of genes was elevated in nematode-infected plants i.e. CHS (chalcone synthase) by 1.32 folds, PAL (phenylalanine ammonia lyase) by 1.16 folds, CS (citrate synthase)1.6 folds, SUCLG1 (succinyl Co-A ligase) by 1.19 folds, SDH (succinate dehydrogenase) by 1.92 folds, FH (fumarate hydratase) by 2.4 foldsand malate synthase (MS) by 1.26 folds and further upregulated after PGPR inoculation. This study demonstrates the importance of PGPR in managing nematode infection in plants through alteration in the synthesis of different secondary metabolites in plants.

Profile of secondary metabolites and genetic stability analysis in new lines of Echinacea purpurea (L.) Moench micropropagated via somatic embryogenesis

Echinacea purpurea (L.) Moench is a plant species important for the phytopharmaceutical industry and in horticulture. Currently, there is lack of standardized plant material with an increased content of secondary metabolites in purple coneflower. The following research meets the expectations of the industry, as new selected lines of purple coneflower were micropropagated by somatic embryogenesis. The plant lines were analyzed both in terms of the content of main secondary metabolites by High Performance Liquid Chromatography (HPLC), as well as the genetic stability within the line and the genetic distance between lines using Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeat (ISSR) genetic markers. Significant differences were found in the relative percentage composition of individual phenolic acids in the tested plant material. Among six selected lines of Echinacea purpurea, three were characterized by a higher content of cichoric acid in relation to the other lines studied. A higher mean polymorphism rate (>90%) was found with the RAPD technique, with a total of 1427 scorable bands produced (142.7 products per one primer). Unlike the RAPD analysis, ISSRs detected mostly monomorphic loci (63.4%), followed by polymorphic ones (36.6%), while there were no specific loci present. Cluster analysis of both marker systems showed that the tested genotypes were grouped according to their respective lines.

Evaluation of Chemical Composition of Two Linseed Varieties as Sources of Health-Beneficial Substances.

Linseed (Linum usitatissimum L.) is becoming more and more important in the health food market as a functional food, since its seeds and oil represent a rich source of bioactive compounds. Its chemical composition is strongly correlated with, and dependent on, genetic characteristics. The aim of this study was to evaluate the variation in seed yield, oil content, fatty acid composition and secondary metabolite profiles between a low-linolenic linseed variety, belonging to the Solin-type group (Solal), and a high-linolenic traditional one (Bethune), cultivated, both as spring crops, in open field conditions of Central Italy. The achieved results pointed out the different behavior of the two varieties in terms of growth cycle, oil content, and some important yield components, such as capsule number per plant and thousand seed weight. There were also significant differences in seed composition regarding total phenols, total flavonoids, antioxidant activities as well as in carotenoid, tocopherol, and tocotrienol profiles between the two varieties. In particular, Solal was characterized by the greatest contents of oil, phenols, flavonoids, α- and δ- tocotrienol, together with the highest antioxidant activity. Bethune, on the contrary, showed the highest amounts of carotenoids (lutein and β-carotene). These results indicate a clear effect of the genetic characteristics on the biosynthesis of these secondary metabolites and, consequently, on the related antioxidant activity. Our findings suggest that the mutation process, responsible for the selection of the low-linolenic cultivar, is able to modify the biosynthetic pathways of carotenoids and phenolics.

Secondary Metabolites Profiling, Proximate Compositions and Antimicrobial Activities of Cordylia Pinnata

Secondary Metabolites Profiling, Proximate Compositions and Antimicrobial Activities of Cordylia Pinnata

Unique secondary metabolites of a Streptomyces strain isolated from extreme salty wetland show antioxidant and antibacterial activities.

To identify and assess the biological activities of the crude extract of a Streptomyces isolate from a salty wetland, an extreme environment likely to induce secondary metabolism of micro-organisms. The crude extract from the isolate Streptomyces lanatus strain AR2 displayed antibacterial activity against Gram-positive bacteria (MICs ranging from 5 to 50μgml-1 ) and antioxidant activity as revealed in DPPH (2,2-diphenyl-1-picrylhydrazyl) assay (IC50 of 0·74mgml-1 ), ferric reducing antioxidant power (IC50 of 1·12mgml-1 ) and metal-chelating power (IC50 of 1·84mgml-1 ) assays. Accordingly, the extract attenuated the H2 O2 -induced oxidative stress in the eukaryotic cell model Saccharomyces cerevisiae, assessed by flow cytometry. The profiling of secondary metabolites by HPLC-PDA-ESI-MS/MS revealed the presence of 17 compounds, some of which reported in Streptomyces for the first time to the best of our knowledge: genistein-7-O-glucuronide, naringenin-7-O-rutinoside and resveratrol. Streptomyces lanatus AR2 produced unique polyketides and phenolic compounds with noticeable bioactivities, allowing adaptation to the extreme environment. Sabkhat Seijoumi salty wetland represents a potential niche for Streptomyces yielding useful natural products for biotechnological, pharmaceutical and medical applications.

De novo transcriptome provides insights into the growth behaviour and resveratrol and trans-stilbenes biosynthesis in Dactylorhiza hatagirea - An endangered alpine terrestrial orchid of western Himalaya

This is the first report on de novo transcriptome of Dactylorhiza hatagirea, a critically-endangered, terrestrial orchid of alpine Himalayas. The plant is acclaimed for medicinal properties but little is known about its secondary-metabolites profile or cues regulating their biosynthesis. De novo transcriptome analysis was therefore, undertaken to gain basic understanding on these aspects, while circumventing the acute limitation of plant material availability. 65,384 transcripts and finally, 37,371 unigenes were assembled de novo from a total of 236 million reads obtained from shoot, tuber and leaves of the plant. Dominance of differentially-expressing-genes (DEGs) related to cold-stress-response and plant-hormone-signal-transduction; and those involved in photosynthesis, sugar-metabolism and secondary-metabolite-synthesis provided insights into carbohydrate-partitioning in the plant during its preparation for freezing winter at natural habitat. DEGs of glucomannan, ascorbic acid, carotenoids, phylloquinone/naphthoquinones, indole alkaloids, resveratrol and stilbene biosynthesis revealed the secondary-metabolite profile of D. hatagirea. UHPLC results confirmed appreciable amounts of resveratrol and trans-stilbene in D. hatagirea tubers, for the first time. Expression analysis of 15 selected genes including those of phenylpropanoid pathway confirmed the validity of RNA-seq data. Opportunistic growth, temperature- and tissue-specific-differential-expression of secondary metabolite biosynthesis and stress tolerant genes were confirmed using clonal plants growing at 8, 15 and 25 °C.

In vitro acaricide activity of extracts from three Leucaena spp. genotypes versus Rhipicephalus microplus

El objetivo del presente estudio fue evaluar la actividad acaricida de extractos etanólicos de tres genotipos de Leucaena spp: L. leucocephala (Lam.) de Wit (Nativa), L. leucocephala (Cunningham) y L. Leucocephala x L. padilla (KX2), sobre larvas y garrapatas adultas de Rhipicephalus microplus. Para evaluar la actividad acaricida se usaron las pruebas de inmersión de larvas e inmersión de adultas. Asimismo, en los extractos de los tres genotipos de Leucaena spp. se analizó el perfil de metabolitos secundarios mediante placas analíticas de cromatografía. Los extractos a concentración del 50 % mostraron una mortalidad en larvas de 91.68, 82.00 y 54.06 % para los genotipos Cunningham, KX2 y Nativa, respectivamente. El genotipo Nativa presentó el mejor comportamiento para el control de R. microplus adultas con un 50 % de mortalidad a la concentración de 20 %. En los extractos se identificaron flavonoides y terpenos que pudieran ser los responsables de la actividad acaricida de los tres genotipos de Leucaena; sin embargo, se requiere de más estudios para identificar los metabolitos que tengan una acción individual o en sinergia en el control de R. microplus.

Effect of explant source, perlite nanoparticles and TiO2/perlite nanocomposites on phytochemical composition of metabolites in callus cultures of Hypericum perforatum

It appears that the biologically-synthesized nanoparticles (NPs) have potential to perform as effective elicitors for the production of valuable secondary metabolites in plants. Besides, it has been reported that the toxicity of the biologically-synthesized NP is not as much as that of the chemically-synthesized NPs. Therefore, it is necessary to test their advantages aspects. In this study, the physical synthesis of perlite NPs and biologically-synthesis of TiO2/perlite nanocomposites (NCs) were conducted. Subsequently, their effects and explant source influence on the growth characteristics and secondary metabolite profiles of Hypericum perforatum callus cultures were evaluated. According to the obtained results, morphology of the synthesized perlite NPs and TiO2/perlite NCs were mesoporous and spherical with sizes ranging about 14.51–23.34 and 15.50–24.61 nm, respectively. Addition of perlite NPs and TiO2/perlite NCs to the culture medium at the concentration range of 25–200 mg/L showed no adverse impacts on the growth characteristics of H. perforatum calli. According to the GC-MS analysis, the stress caused by perlite NPs and TiO2/perlite NCs led to an increase in the variety, amount and number of volatile compounds. The calli obtained from in vitro grown plants produced more volatile compounds relative to the calli obtained from field grown plants under the nanomaterial stress conditions. The production of hypericin and pseudohypericin were also determined in the callus cultures under desired nanomaterials elicitation. Accordingly, our results suggest that perlite NPs and TiO2/perlite NCs can possibly be considered as effective elicitors for the production of volatile compounds, hypericin, and pseudohypericin in callus cultures of H. perforatum.

Comparison of in vitro antioxidative activities of crude methanolic extracts of three species of Passiflora from greenhouse using DPPH, ABTS and FRAP methods

Summary Introduction:. It is well documented that many species from Passifloraceae family can provide edible and nutritious fruits while the leaves of cultivated plants are renewable and waste material. This biomass may be further used in various sectors, especially as a bioactive food additive and as source of innovative pharmaceuticals, cosmetics or feed additives. The biomaterials and green chemistry are new sectors bioeconomy according to the high-level horizontal strategies and bio-based industries in Europe. In recent years, attention has been paid to the biological activity and phytochemical profiles of extracts from different species of Passiflora. However, there is little comparative studies using the same procedures and techniques in the same laboratory conditions for study of plant material obtained from the similar greenhouse conditions. Objective: This study was focused on the examination of antioxidative activities of low concentrations of crude extracts from leaves of Passiflora incarnata L., Passiflora caerulea L., and Passiflora alata Curtis. Methods: The activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging and ferric reducing antioxidant power (FRAP) methods. Results of study were supported by estimation of chemical composition with secondary metabolites profiling in extracts which were carried out previously for the same extracts from three Passiflora species. One-way ANOVA analysis revealed significant differences in the antioxidant activity of various concentrations of the extracts using the DPPH and ABTS radical models, and FRAP method. Results: Measurement of antioxidant capacity (expressed as trolox equivalent, TE) showed that the most active was extract of P. caerulea > P. alata > P. incarnata. Phytochemical analysis for extracts of P. caerulea and P. incarnata showed greater similarities in metabolites content than P. alata. However, comparative statistical analysis of antioxidant activity showed that despite this phytochemical similarities, extract from P. alata leaves had higher activities than extract from leaves P. incarnata. Antioxidant effect of extract from P. alata can be explain by terpenoids presented in this extract. In this work, there have been discussed activities against Acanthamoeba castellanii strain, antibacterial and antifungal activities against selected clinical microorganisms (Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, and Candida albicans, Micro-sporum gypseum), and anti-leukemic activities tested in human acute lymphoblastic leukemia cell lines for this extracts, which have been described in previous authors’ publications. Conclusion: Our current and previous studies showed that the same crude extracts from leaves of P. alata, P. caerulea, P. incarnata exerted not only antioxidant potential in vitro but also few interesting properties such as antibacterial, antifungal, amoebostatic, amoebicidal activities, which indicate the possibility of using these extracts in both a healthy diet and natural cosmetics. Leaves of this species may become an interesting source of biomaterials which can exert health-promoting effects.

Enzymatic activity and secondary metabolite profile of Trichoderma asperellum in presence of chitosan

The present research was aimed to study enzymatic activity (cellulase and chitosanase) and secondary metabolite production of Trichoderma asperellum in presence of chitosan. The qualitative assays for cellulase and chitosanase showed enhanced enzymatic activity of the fungus. The H/C ratio obtained was 1.76 and 1.49 at 500 ppm and 250 ppm of chitosan respectively, which was significantly higher, as compared to control (H/C ratio 1.2). For chitosanase activity, the largest purple zone (55.8 mm) was recorded in case of T. asperellum + chitosan 500 ppm which was significantly higher than other treatments. Besides enhancing enzymatic activity, chitosan also increased the production of two important secondary metabolites of T. asperellum viz. Tetradecanoic acid (myristic acid) and 1,2-benzenedicarboxylic acid. GC–MS results revealed that the maximum peak area of chromatogram was covered by tetradecanoic acid (28.23%) followed by 1,2-benzenedicarboxylic acid (18.16%) showing the high concentration of these metabolites as compared to other compounds. The enhanced production of cellulase, chitosanase and secondary metabolites by T. asperellum in presence of chitosan could be exploited for further research in improvement of bio-control activity of bio-agents for integrated plant disease management.

Hormone and secondary metabolite profiling in chestnut during susceptible and resistant interactions with Phytophthora cinnamomi

Phytophthora cinnamomi (Pc) is a dangerous pathogen that causes root rot (ink disease) and threatens the production of chestnuts worldwide. Despite all the advances recently reported at molecular and physiological level, there are still gaps of knowledge that would help to unveil the defence mechanisms behind plant-Pc interactions. Bearing this in mind we quantified constitutive and Pc-induced stress-related signals (hormones and metabolites) complemented with changes in photosynthetic related parameters by exploring susceptible and resistant Castanea spp.-Pc interactions. In a greenhouse experiment, five days before and nine days after inoculation with Pc, leaves and fine roots from susceptible C. sativa and resistant C. sativa × C. crenata clonal 2-year-old plantlets were sampled (clones Cs14 and 111-1, respectively). In the resistant clone, stomatal conductance (gs) and net photosynthesis (A) decreased significantly and soluble sugars in leaves increased, while in the susceptible clone gs and A remained unchanged and proline levels in leaves increased. In the resistant clone, higher constitutive content of root SA and foliar ABA, JA and JA-Ile as compared to the susceptible clone were observed. Total phenolics and condensed tannins were highest in roots of the susceptible clone. In response to infection, a dynamic hormonal response in the resistant clone was observed, consisting of accumulation of JA, JA-Ile and ABA in roots and depletion of total phenolics in leaves. However, in the susceptible clone only JA diminished in leaves and increased in roots. Constitutive and Pc-induced levels of JA-Ile were only detectable in the resistant clone. From the hormonal profiles obtained in leaves and roots before and after infection, it is concluded that the lack of effective hormonal changes in C. sativa explains the lack of defence responses to Pc of this susceptible species.

The Profile of Secondary Metabolites and Other Bioactive Compounds in Cucurbita pepo L. and Cucurbita moschata Pumpkin Cultivars

Plants and animals are sources of various bioactive compounds that exhibit a broad spectrum of health-promoting effects. Scientists continue studies on the chemical composition of many products in search of foods with high nutritional value. The pumpkin (Cucurbita sp.) is unquestionably a source of valuable nutrients. This vegetable is well-known all over the world and it is appreciated due to its high content of carotenoids, but it is still not much used in the processing industry. The aim of present study was to compare the flesh of 15 pumpkin varieties belonging to the Cucurbita pepo and C. moschata species in terms of the bioactive compound content (carotenoids, phenolic acids, flavonols, minerals and vitamins) and to demonstrate whether the variety has an effect on the chemical composition. To date, no such extensive research has been carried out in this area. The research revealed that the pumpkin pulp had high content of carotenoids. In nearly all cases lutein was the most abundant carotenoid. Numerous phenolic acids and flavonols were also identified. All the cultivars contained gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid, chlorogenic acid, caffeic acid, and rutin. The pumpkin pulp also contained alpha- and gamma-tocopherol. No beta- or delta-tocopherol was found. Potassium, calcium, and sodium were the most abundant minerals. The research also proved that the profile of bioactive compounds in the pumpkin pulp was considerably diversified and depended on the species and cultivar

Application of 1 H-NMR-based metabolomics to the analysis of cranberry (Vaccinium macrocarpon) supplements.

Commercial cranberry supplements provide a low-sugar alternative to juices and sweetened fruit consumed for health benefits, but their phytochemical composition and associated biological activity varies depending on the source material and post-harvest processing. Proton nuclear magnetic resonance (1 H-NMR) is a rapid and environmentally friendly method of generating metabolic profiles of plant materials that may be used to authenticate cranberry products. The 1 H NMR-based chemometrics were used to characterise variations in metabolic profiles of cranberry supplements in comparison to a whole cranberry powder reference standard. The secondary metabolite profiles of nine commercial cranberry supplements were compared to a whole cranberry powder reference standard, using 1 H-NMR with Bruker AssureNMR software and principal component analysis (PCA). Content of selected triterpenoids and organic acids was determined by quantitative NMR. Total proanthocyanidins and anthocyanins were determined by established methods. PCA of 1 H-NMR spectra showed overlap between the cranberry standard and three supplements, but most products varied substantially in metabolic profile. Metabolites contributing to the observed variance include citric acid and cranberry peel constituents ursolic acid, oleanolic acid and hyperoside. Ursolic, oleanolic, citric, quinic and malic acids were readily determined by quantitative 1 H-NMR in the whole cranberry standard, but were below detection limits in many supplements. Proanthocyanidin and flavonoid content in several products was minimal or below detection limits. The 1 H-NMR chemometrics found significant variation in composition of characteristic cranberry metabolites among commercial preparations, reinforcing the need for reliable industry standards.

Understanding scion-rootstock interactions at the graft interface of grapevine

In viticulture, grafting is used to facilitate grapevine cultivation in soils infected with phylloxera, a soil-dwelling insect pest introduced to Europe from America at the end of the 19th century. Successful grafting of plants is a complex biochemical and structural process that begins with an initial wound response, followed by callus formation and the establishment of a functional vascular system between the two grafting partners. Despite the importance of the scion-rootstock interface in viticulture, we know little of the processes involved in forming a successful graft union. Developments at the scion-rootstock interface of grapevine have been studied using a variety of techniques. Morphological developments have been studied using microscopy techniques and X-ray computed tomography, and xylem connectivity has been assessed by using a high- and low-pressure flow meter. Microarrays have been used to identify genes that are differentially expressed between the wood and graft interface tissues of homo-grafts (the same genotype grafted together) and at the graft interface between different scion-rootstock combinations (hetero-grafts). Primary and secondary metabolite profiling has also been done. An overview of the interdisciplinary approaches currently being used to piece together the puzzle of graft union formation in an important woody, perennial crop will be presented.

Rapid Metabolome and Bioactivity Profiling of Fungi Associated with the Leaf and Rhizosphere of the Baltic Seagrass Zostera marina

Zostera marina (eelgrass) is a marine foundation species with key ecological roles in coastal habitats. Its bacterial microbiota has been well studied, but very little is known about its mycobiome. In this study, we have isolated and identified 13 fungal strains, dominated by Penicillium species (10 strains), from the leaf and the root rhizosphere of Baltic Z. marina. The organic extracts of the fungi that were cultured by an OSMAC (One-Strain–Many-Compounds) regime using five liquid culture media under both static and shaking conditions were investigated for their chemical and bioactivity profiles. All extracts showed strong anti-quorum sensing activity, and the majority of the Penicillium extracts displayed antimicrobial or anti-biofilm activity against Gram-negative environmental marine and human pathogens. HPLC-DAD-MS-based rapid metabolome analyses of the extracts indicated the high influence of culture conditions on the secondary metabolite (SM) profiles. Among 69 compounds detected in all Penicillium sp. extracts, 46 were successfully dereplicated. Analysis of SM relatedness in culture conditions by Hierarchical Cluster Analysis (HCA) revealed generally low similarity and showed a strong effect of medium selection on chemical profiles of Penicillium sp. This is the first study assessing both the metabolite and bioactivity profile of the fungi associated with Baltic eelgrass Z. marina.

Modulation of secondary metabolite profiles by biologically synthesized MgO/perlite nanocomposites in Melissa officinalis plant organ cultures

In this work, biological synthesis of MgO/perlite nanocomposites (NCs) besides their effects on morphology and secondary metabolite profiles of Melissa officinalis plant organ cultures were evaluated. MgO NPs were immobilized on the surface of nanoperlite using M. officinalis extract as a capping agent. The as-synthesized MgO/perlite NCs were characterized by using FTIR, XRD, SEM, EDS and DLS. The average particle size of nanoperlite and MgO/perlite NCs was about 10 and 30 nm, respectively. Morphological observations showed that nanoperlite and MgO/perlite NCs had no effect on root number, as well as root and shoot length. None of the applied concentrations of perlite and MgO/perlite NCs could significantly increase the growth parameters in comparison to the control, except for 150 mg/L of nanoperlite which caused an increase in the shoot number. Although, the contents of chlorophyll and carotenoids were not affected, the maximum content of volatile compounds obtained at 100 of MgO/perlite NCs. Rosmarinic acid was detected in shoots, which treated with 25–100 mg/L of perlite and 25, 50 and 150 mg/L of MgO/perlite NCs. Our results provided the evidence that nanoperlite and MgO/perlite NCs at specific levels may act as a novel elicitor for in vitro biosynthesis of valuable secondary metabolites.