Endophytic Fungal Strains Research Articles

Elicitors derived from endophytic fungi Chaetomium globosum and Paraconiothyrium brasiliense enhance paclitaxel production in Corylus avellana cell suspension culture

Paclitaxel is an impressive chemotherapeutic agent that shows biological activity against a wide range of cancers. Cell suspension culture of Corylus avellana has been reported as an alternative source for production of the valuable secondary metabolite, paclitaxel. The fungal elicitors have been considered as the most impressive strategy for enhancement of secondary metabolites in plant cell culture. In this study, two endophytic fungal strains YEF20 and HEF114 were isolated from Taxus baccata and C. avellana, respectively. The isolates YEF20 and HEF114 were identified as Chaetomium globosum and Paraconiothyrium brasiliense, respectively by sequencing of ITS1-5.8S-ITS2 rDNA region. This is the first report of P. brasiliense on C. avellana tree. Also, this study presents the positive effect of fungal elicitors on paclitaxel production in C. avellana for the first time. The effect of fungal elicitors on paclitaxel production was dependent on fungal species, and also type, concentration and adding time of elicitors to cell culture. The highest total yield of paclitaxel in cell culture treated with cell extract (CE) of C. globosum (291.5 µg L−1) was obtained by using 10% (v/v) of this fungal elicitor on 17th day of cell culture cycle (late log-phase), which was about 4.1 times obtained in the control culture. The cell culture treated with C. globosum CE had an average growth rate of 0.491 g L−1 day−1, i.e. 12.3% lower than that in the control. Among the fungal elicitors, 10% (v/v) CE of C. globosum on 17th day of culture cycle showed the best results with respect to extracellular paclitaxel portion (44.0%). Paclitaxel secretion to culture medium is essential for large-scale steady production of paclitaxel.

Effect of Fermentation Broth of Endophytic Fungi on Physiological and Biochemical Characteristics of Tomato Seedling Under Calcium Nitrate Stress

In this research, the fermentation broth produced from seven strains of endophytic fungi was sprayed on tomato plants at seedling stage. This process was carried out under Ca(NO3)2 stress, with comparison to the commercial microbial fertilizer to study the physiological and biochemical characteristics of tomato seedling. The results showed that most of the fermentation broths have no phytotoxicity and could improve salt resistance of tomato. The fermentation broth of strain Schizophyllum sp. DL12 displayed the best effects which increased the chlorophyll content (0.244 mg g−1 FW), soluble protein (31.48 µg g−1 FW), proline content (305.6 µg g−1 FW), peroxidase (21.78 µg g−1 FW min−1) and catalase (0.345 µg g−1 FW min−1) activities in leaves significantly as compared with control (CK) and commercial microbial fertilizer. These findings indicated that fermentation broth of Schizophyllum sp. DL12 has bright prospects of applications.

EVALUATION OF ANTIBACTERIAL ACTIVITY OF ENDOPHYTIC FUNGI ASPERGILLUS JAPONICUS ISOLATED FROM TRIDAX PROCUMBENS L.

Objective: The main purpose of the present study was to isolate the endophytic fungi from Tridax procumbens L. and evaluate their antibacterial activity at different concentration of compatible solvents extracted metabolites against the test pathogenic bacterial strain, as well as the molecular characterization of potent endophytic fungal isolate that showed the maximum antibacterial activity.Methods: The endophytic fungi were isolated from the different parts of the collected T. procumbens plant. Screening of endophytic fungi for the antibacterial activity was scrutinized against five pathogenic bacteria such as Bacillus subtilis, Streptococcus pyogenes, Escherichia coli, Klebsiella pneumoniae, and Salmonella typhimurium using agar well diffusion method. After screening, the metabolite of the potent fungal isolate was extracted using different solvents by solvent-solvent extraction procedure and observed their antibacterial activity. For molecular identification of the fungi, the DNA was extracted, quantified, and amplified using two oligonucleotide primers ITS4 and ITS6 in polymerase chain reaction.Results: In the present study, five endophytic fungi were isolated from medicinal plant T. procumbens and screened for their antibacterial activity against E. coli (22.60±0.32 mm), S. typhimurium (19.26±0.23 mm), S. pyogenes (16.36±0.18 mm), K. pneumoniae (14.26±0.54 mm), and B. subtilis (14.43±0.27 mm) bacterial strain. The endophytic fungal strain A. japonicus isolated from T. procumbens was showed the significant antibacterial activity against the pathogenic bacteria. The morphological identification of all the isolated endophytic fungi was observed on the basis of their macroscopic and microscopic characteristics, and the molecular identification of the potent fungal strain was observed through 18s rRNA sequence analysis. Using solvent-solvent extraction technique, different solvent residues of the potent fungal metabolite were extracted in benzene, n-,butanol and toluene. The n-butanol solvent extract exhibited a maximum zone of inhibition against the test bacterial strains.Conclusion: The present study reveals that the endophytic fungi serve as a potential source for the production of effective bioactive compounds.

ANTIMICROBIAL AND CYTOTOXIC ACTIVITIES OF ALKALOIDS PRODUCED BY ENDOPHYTIC FUNGI

In this study, 55 endophytic fungal strains isolated from alkaloid containing plants in Mongolia were screened for their production of alkaloids. TLC analysis of ethanolic crude extracts revealed the presence of alkaloids in 5 endophytic fungal strains. The alkaloid producing strains were identified based on their morphological characteristics and/or the D1/D2 domain sequences of 28S rRNA gene. The results showed that they all belong to the genus of Fusarium. Further, total alkaloid compounds of the 5 fungal strains were isolated and examined for their antimicrobial and cytotoxic activities. As results, alkaloid compounds of SFG-S1 and 16T6-F3 strains were active against yeast and fungi, and alkaloid compounds of SFG-R3, 16Т6-F3, 14R-1 strains exhibited cytotoxic activity against HepG2 liver cancer cells.

Diversity, antibacterial activites and growth promoting characteristics of endophytic fungi from sandal (Santalum album)

The aim of this study was to investigated the biological diversity, antibacterial activites and the plant growth-promoting traits of endophytic fungi of sandal (Santalum album), and to assess their potential in the development of antibacterial substances and rapid cultivation of sandal. The results of isolation and taxa analysis of endophytic fungi from sandal showed that 325 strains of endophytic fungi belonging to 16 genera of endophytic fungi were isolated from sandal (of which 86 from roots, 105 from stems and 134 from leaves). The isolation rate and colonization rate of endophytic fungi in different sandal parts showed the same pattern of change: leave>stems>roots. The diversity index of endophytic fungi in sandal roots was significantly higher than that of stems and leaves. The dominant endophytic fungi of sandal roots, stems and leaves showed significant differences. The dominant endophytic fungi of roots were Fusarium (50.00%) and Alternaria (10.47%), Alternaria (58.11%) and Acremonium (20.00%) for stems, and Pantoea (74.63%) for leaves. The antibacterial activity of 40 representative strains of sandal endophytic fungi were analyzed and the results showed that 90% of endophytic fungi exhibited inhibitory activity against at least one of the tested bacteria strains, and the strains with inhibitory activity to Escherichia coli, Enterobacter aerogenes, Shigella dysenteriae, Salmonella typhimurium, Staphylococcus aureus, and Bacillus subtilis accounted for 45.0%, 30%, 47.5%, 55%, 72.5%, and 62.5%, respectively. The sandal fungal endophytes with plant growth-promoting characteristics were screened, and 5 strains of endophytic fungi with phosphorus-solubilizing activity, 8 strains of endophytic fungi producing IAA, and 4 strains of endophytic fungi producing siderophores were found. Among them, endophytic fungus Monilia sp TXRF45 clould produced IAA and siderophores, and also show phosphate-solubilizing activity. The results indicated that the endophytic fungi of Sandal were rich in species diversity and their distribution had a certain tissue specificity. Some strains showed good antibacterial activity and growth-promoting properties, which could potentially applicable for the development of antibacterial substances and rapid cultivation of sandal.

Hongos endófitos foliares como candidatos a biocontroladores contra <i>Moniliophthora</i> spp. de <i>Theobroma cacao</i> (Malvaceae) en Ecuador

La adaptabilidad de los hongos endófitos a sus hospedantes, los beneficios ecológicos que le brinda y los diversos mecanismos antagónicos contra plagas que poseen los convierten en una alternativa para el control biológico de enfermedades. Se determinó el potencial de 17 cepas de hongos endofíticos foliares (FEF) obtenidas de tejido sano de Theobroma cacao como candidatas para el control biológico de Moniliophthora roreri (MR) y M. perniciosa (MP). Se evaluaron: i) el micoparasitismo de los FEF frente a colonias de Moniliophthora spp., ii) la acción de los metabolitos crudos de los FEF en el crecimiento, y iii) la habilidad para recolonizar hojas sanas del hospedante mediante ensayos de hojas sueltas. Tres cepas de Lasiodiplodia theobromae fueron las más promisorias: Ec098, Ec151 and Ec157. Estas cepas inhibieron el crecimiento de MR y MP, tanto en el enfrentamiento de las colonias como mediante sus metabolitos y, adicionalmente, recolonizaron el hospedante entre el 80-100 % de las veces. Otras cepas mostraron valores destacados en un indicador, y no deseables en otros. Por ejemplo, la Ec035 (L. theobromae) mostró los niveles más altos de micoparasitismo contra ambos patógenos en la interacción de las colonias, y el segundo mejor por sus metabolitos, pero no pudo reinfectar el hospedante. La cepa Ec059 (Xylaria feejeensis) reinfectó 100 %, pero no mostró los atributos deseados de antagonismo. Por su parte, los metabolitos de Ec107 (Colletotrichum gloeosporioides s.l.) inhibieron a MR en un 60 %, pero también estimularon el crecimiento de MP. Ninguna cepa logró todas las características deseables para un agente de control biológico.

Endophytic Fungal strains Specifically Modified the Biochemical Status of Grape Cells

Previously, specific interactions in morphology were observed between grape cells and endophytic fungal strains during a dual culture experiment. However, the biochemical impacts of these fungal endophytes on grape cells is also expected due to their potential application in grape quality management. After assessed multiple physiochemical traits to those grape cells which have co-cultured with different endophytic fungal strains in this study, and found the presence of fungal endophytes obviously triggered ROS stress responses in grape cells, and the biochemical status in grape cells were differentially modified by different fungal strains. In those tested endophytic fungal strains, RH37 (Epicoccum sp.), RH6 (Alternaria sp.), RH32 (Alternaria sp.) and RH34 (Trichothecium sp.) conferred greater metabolic impacts on grape cells. And soluble protein (SPr), total flavonoids (TF), total phenols (TPh) and malondialdehyde (MDA) on the other hand, were sensitive biochemical parameters which can be influenced in greater ranges than other detected parameters. Most interestedly, fungal endophytes shaped metabolites patterns in grape cells during the dual culture appeared fungal genus/species/strain-specificity. The work confirmed the significance of fungal endophytes in grape metabolic regulation and elucidated the possibility to purposely manage grape quality using tool of fungal endophytes.

In vitro salt and thermal tolerance of fungal endophytes of Nicotiana spp. growing in arid regions of north-western Australia

Endophytic fungal strains isolated from indigenous Nicotiana plants naturally growing in dry and hot regions of north-western Australia were characterised based on their tolerance to salinity and temperature. Sixty-eight fungal isolates were tested on eight levels (0.5 M, 1.0 M, 1.5 M, 2.0 M, 2.5 M, 3.0 M, 3.5 M and 4.0 M) of five different of salts solutions NaCl, KCl, MgCl2, CaCl2 and MgSO4 and at various temperatures (25–50 °C). The salt adaptation test indicated that the fungal strains namely Aspergillus niger (E-202), A. ochraceous-A (E-134), Aurantiporus sp. (E-135), Cladosporium halotolerance (E-128), Pleurostomophora richardsiae (E-13) and Trichoderma sp. (E-185.1) were tolerant to higher concentrations of various salts. The most growth-limiting salt turned out to be MgCl2 followed by the chaotrope CaCl2. Responses to temperature tolerance revealed that most fungi tested could grow at 30 °C. About 50% all the fungi did not show any growth when the temperature was raised above 30 °C. When the temperature was raised up to 50 °C all the fungi failed to grow but the fungus Rasamsonia piperina (E-172). Endophyte strains identified could be promising candidates for future research in investigating the fungus–plant interactions and their roles in plant adaptation to inhospitable environments.

Identification and characterization of new Muscodor endophytes from gramineous plants in Xishuangbanna, China.

The endophytic fungi Muscodor spp. produce volatile organic compounds (VOCs) which can inhibit and even kill pathogenic fungi, bacteria, and nematodes. Nine endophytic fungal strains, isolated from the shoots of gramineous plants including Arthraxon hispidus, Eleusine indica, Oplismenus undulatifolius, and Oryza granulata, were identified as Muscodor through phylogenetic analysis of the internal transcribed spacer. Through an SPSS K‐means cluster analysis, the nine Muscodor strains were divided into four groups based on the antifungal activities of the VOCs produced by these fungi determined by a two‐section confrontation test. The first group contains the strains Y‐L‐54, W‐S‐41, Y‐S‐35, W‐T‐27, and Y‐L‐56, which showed the strongest activity. The second and third groups contain W‐S‐35 and Y‐L‐43, which showed stronger and moderate activity, respectively. The fourth group contains W‐S‐38 and N‐L‐7, which were the weakest in inhibiting the tested pathogens. Thirty‐five compounds and the relative amounts of VOCs were determined by SPME‐GC‐MS and comparison with the NIST14 mass spectrometry database and Agilent MassHunter qualitative and quantitative analyses. These 35 compounds were classified into two different categories: (a) the product of fatty acid degradation, and (b) the intermediate and final metabolite of the metabolic pathway with the precursor of mevalonic acid. SPSS clustering analysis showed that the chemical components of VOCs might be correlated with their bioactivity rather than their phylogenetic assignment and some of the identified compounds might be responsible for antifungal activity. In conclusion, new Muscodor endophytes were recorded in tropical gramineous plants and a number of strains showed remarkable bioactive properties. Therefore, they have important potential applications in the fields of plant disease control.

Phylogenetic analysis and diversity of novel endophytic fungi isolated from medicinal plant Sceletium tortuosum

Throughout history, mankind has used plants as their primary source of sustainability, in agricultural commodities, clothing, fragrances, fertilizers, flavours, and providing shelter. There is a strong symbiotic relationship between the plant and its endophytes. Endophytes are harboured within the living plant tissues without causing neither diseases nor symptoms. They produce bioactive compounds that protect the host plants against attack of insects, pathogens and herbivores. The bioactive compounds might be utilized for pharmaceutical, agricultural, or biotechnological applications.This paper reported on the various endophytic fungi strains that were isolated from isolated from a medicinal plant, Sceletium tortuosum. Fifty Sceletium tortuosum plants were collected from three different provinces in South Africa and leaves and roots used to isolate culturable endophytes. Morphological characteristics and a genus specific PCR designed to amplify fungal internal transcribe spacer (ITS) region (ITS1 and ITS4) and elongation factor (EF 1 and 2) was used for identification. A total of 60 fungal isolates belonging to 16 genera were identified and classified. Isolates were identified to species level based on similarities with known sequences in GenBank and a large proportion of the fungi were Fusarium species (37%) followed Aspergillus (25%) and Penicillium (7%) species. Phylogenetic analysis was performed using nuclear ribosomal DNA sequences and three potentially new isolates (DR 019 Fusarium penzigii, DR 010 Phomopsis columnaris, DR 007 Fusarium oxysporum f. sp. lycopersici) were identified in the phylogenic tree that was constructed. Our results offers basic data on the symbiotic/or mutualistic relationship between the medicinal plant Sceletium tortuosum and its endophytic fungi, as well as novel species.

Elevation of plant growth parameters in two solanaceous crops with the application of endophytic fungus

In the present study VBEF2, an endophytic fungal strain of Aspergillus isolated from the leaf of Schima wallichii (DC.) Korth. showed excellent plant growth promoting (PGP) attributed both in-vitro and in-vivo conditions. It was found to possess good phosphate solubilizing and IAA producing ability as it produced soluble phosphate and IAA upto 418.33 µg ml-1 and 19.8 µg ml-1, respectively in the seven days kinetic studies. It also exhibited siderophore producing attribute with remarkable antifungal activities against potential plant pathogens Fusarium oxysporum, Colletotrichum acutatum and Penicillium digitatum. It showed excellent survivability in alluvial soil in laboratory condition at a temperature range of 28ºC to 50ºC. The strain when subjected to field application enhanced various growth and yield parameters significantly (p Lass Than 0.05) in Solanum lycopersicum (tomato) and Solanum melongena (brinjal).

Antifungal activities of cytochalasins produced by Diaporthe miriciae, an endophytic fungus associated with tropical medicinal plants.

In the present study, we evaluated the antifungal potential of cytochalasins produced by Diaporthe taxa against phytopathogenic fungi. Using molecular methods, seven endophytic fungal strains from the medicinal plants Copaifera pubiflora and Melocactus ernestii were identified as Diaporthe miriciae, while two isolates were identified to the genus level (Diaporthe sp.). All crude extracts of Diaporthe species produced via solid-state fermentation were evaluated by 1H NMR analyses. Crude extracts of the isolates D. miriciae UFMGCB 6350, 7719, 7646, 7653, 7701, 7772, and 7770 and Diaporthe sp. UFMGCB 7696 and 7720 were demonstrated to produce highly functionalized compounds. The extracts of D. miriciae UFMGCB 7719 and 6350 were selected as representative Diaporthe samples and subjected to bioassay-directed fractionation to isolate cytochalasins H and J. Cytochalasins H and J were evaluated for activities against the fungal plant pathogens Colletotrichum fragariae, Colletotrichum gloeosporioides, Colletotrichum acutatum, Botrytis cinerea, Fusarium oxysporum, Phomopsis obscurans, and Phomopsis viticola using microdilution broth assays. Cytochalasins H and J exhibited the most potent activities against the Phomopsis species tested. Our results showed that Diaporthe species were potential producers of different cytochalasins, which exhibit potential for controlling fungal diseases in planta and (or) maintaining antagonism.

An endophytic Fungi of Ginkgo biloba L. produces antimicrobial metabolites as potential inhibitors of FtsZ of Staphylococcus aureus

A total of 58 fungal isolates, belonging to 24 genera, were obtained from the leaves, stems and roots of Ginkgo biloba L.. Among them, one endophytic fungal strain, Penicillium cataractum SYPF 7131, displayed the strongest antibacterial activity. Four new compounds (1–4) were isolated from the strain fermentation broth together with four known compounds (5–8). These structures were determined on the basis of 1D and 2D NMR and [Rh2(OCOCF3)4]-induced electronic circular dichroism (ECD) spectroscopic analyses. All the isolated compounds were screened for their in vitro antimicrobial activities. Compound 3 and 4 showed moderate inhibitory activity against Staphylococcus aureus. Compound 7 exhibited significant inhibitory activity against S. aureus with MIC value of 10 μg/mL. Further, the in silico molecular docking studies of the active compounds was used to explore the binding interactions with the active site of filamentous temperature-sensitive protein Z (FtsZ) from Staphylococcus aureus. The docking results revealed that compounds 3, 4 and 7 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ from S. aureus validating the observed antimicrobial activity. Based on antimicrobial activities and docking studies, compounds 3, 4 and 7 were identified as promising antimicrobial lead molecules.

Cellulases and xylanases production by endophytic fungi by solid state fermentation using lignocellulosic substrates and enzymatic saccharification of pretreated sugarcane bagasse

Endophytic fungi are widely studied as producers of secondary metabolites of biotechnological interest. In recent years, the interest in these fungi as new sources of enzymes, especially hydrolytic, has increased. In the present study, 14 strains of endophytic fungi not yet explored as enzymes sources were randomly chosen and prospected for cellulases and xylanases production by solid-state fermentation. Initially, fungi were cultivated in a mixture (1:1 w/w) of sugarcane bagasse and wheat bran for 7 days, at 28 °C. In this initial screening, 4 fungi excelled in endoglucanase activity (U/g): Cladosporium cladosporioides PAJ 03 (88.51 ± 1.0), Phomopsis stipata SC 04 (83.44 ± 7.7), Trichoderma viridae PAJ 01 (64.56 ± 4.0) and Botryosphaeria sp. AM 01 (42.79 ± 1.6). On the other hand, the following 4 fungi stood out in relation to β-glucosidase activity (U/g): Saccharicola sp. EJC 04 (51.56 ± 2.7), Paecilomyces sp. SF 021 (33.19 ± 9.2), Ustilaginoidea sp. CV 04 (29.75 ± 0.8) and Ustilaginoidea sp. XYA 04 (21.72 ± 3.05). Among these fungi, P. stipata SC 04 and Botryosphaeria sp. AM 01 were the best producers of xylanase and β-xilosidase (694,33 and 4,87 U/g, respectively). These 8 fungi were then cultured in new mixtures (1:1 w/w) of lignocellulosic substrates. Botryosphaeria sp. AM01and Saccharicola sp. EJC04 stood out regarding endoglucanase and β-glucosidase activities (184.74 ± 6.0 and 92.28 ± 9.57 U/g, respectively) when cultivated on cotton seed meal and wheat bran and were selected to continue the study. The influence of time cultivation, inoculum amount and substrate initial moisture content was evaluated and the best condition for cellulases production was 192 h, six mycelial plugs and 65%, respectively, for both fungi. Cellulases and xylanases produced under these conditions were characterized and optimum pH and temperature values were between 4.5–6 and 60–75 °C, respectively. The enzymes were stable over a wide pH range and under 30–70 °C. β-glucosidase from both isolates retained about 75–80% of their activity in the presence of glucose at 6 mM. The presence of ethanol stimulated β-glucosidase activity from Botryosphaeria sp. AM01 (about 60% higher in the presence of ethanol at 15%). On the other hand, the activity of β-glucosidase produced by Saccharicola sp. EJC 04 was reduced at ethanol concentrations above 15%. A blend of the enzymatic extracts was used to saccharify pretreated sugarcane bagasse and a face-centered central composite design was used to find the best conditions. Under the predicted optimum condition (50 °C, 5% of sugarcane bagasse, 150 U g−1 of endoglucanase and 20 h), glucose and xylose concentrations obtained were 3.56 and 1.66 mg mL−1, respectively. These results show that the 14 endophytic fungi studied have potential to be explored as producers of plant material degrading enzymes. Botryosphaeria sp. AM01 and Saccharicola sp. EJC 04 are promising in relation to the production of cellulases and xylanases and their enzymatic extracts have potential for application in pre-treated sugarcane bagasse saccharification processes.

Two new 12-membered macrolides from the endophytic fungal strain Cladosprium colocasiae A801 of Callistemon viminalis

Two new polyketide metabolites, the 12-membered macrolides 4-hydroxy-12-methyloxacyclododecane-2,5,6-trione (1) and 12-methyloxacyclododecane-2,5,6-trione (2), were isolated from the endophytic fungal strain Cladosprium colocasiae A801 of the plant Callistemon viminalis, together with five known derivatives. Their structures were fully characterized by means of detailed spectroscopic analysis for new structures, and in comparison with published data for known compounds. The antibacterial, cytotoxic, and α-glucosidase inhibitory activities of the new compounds 1 and 2 were evaluated.

Endophytic fungi specifically introduce novel metabolites into grape flesh cells in vitro.

Since endophytes can affect metabolism of host plants, they are expected to be used to improve crop quality, especially for crops with organoleptic sensitive products such as wine grape. However, details of metabolic interactions between endophytes and host plants were less understood. In this work, we used high pressure liquid chromatography (HPLC) to analyze the metabolites of fruit flesh cells of grape treated with dual culture of different endophytic fungal strains (EFS). We observed that the dual-culture with different fungal strains show different metabolites composition in grape cells. In response to different EFS, quantities of detected metabolites in grape cells varied from 6 to 17 in this assay, and 1 to 11 novel metabolites were introduced into metabolome of grape cells. Dual-culture with fungal strains CS2, RH16 and RH5 introduced the highest quantities (10 or 11) of novel metabolites in grape cells. More importantly, the modification of metabolic profiles in grape cells via fungal endophytes appeared to be fungal strain/genus-specificity. Overall, this work revealed that introduction of specific metabolites in host plants may be one consequence during the process of endophytes-host metabolic interactions, which raise the possibility to shape grape qualities and characteristics using tool of fungal endophytes.

Isolation of endophytic fungi from Dioscorea zingiberensis C. H. Wright and application for diosgenin production by solid-state fermentation.

In this study, endophytic fungi were isolated from Dioscorea zingiberensis C.H. Wright (DZW), and a novel clean process to prepare diosgenin from DZW was developed. A total of 123 strains of endophytic fungi were isolated from different plant tissues of DZW. Among them, the strain Fusarium sp. (CPCC 400709) showed the best activity of hydrolyzing steroidal saponins in DZW into diosgenin. Thus, this strain was used to prepare diosgenin from DZW by solid-state fermentation. The fermentation parameters were optimized using response surface methodology, and a high yield of diosgenin (2.16%) was obtained at 14.5% ammonium sulfate, an inoculum size of 12.3%, and 22days of fermentation. Furthermore, the highest diosgenin yield (2.79%) was obtained by co-fermentation with Fusarium sp. (CPCC 400709) and Curvularia lunata (CPCC 400737), which was 98.9% of that obtained by β-glucosidase pretreated acid hydrolysis (2.82%). This process is acid-free and wastewater-free, and shows promise as an effective and clean way to prepare diosgenin for use in industrial applications from DZW.

Chemical interaction of endophytic fungi and actinobacteria from Lychnophora ericoides in co-cultures

Microorganisms interact chemically in natural environments; however, the compounds and mechanisms involved in this phenomenon are still poorly understood. Using the cocultivation approach, changes in metabolic profiles due to interactions between endophytic fungal and actinobacterial strains isolated from the plant Lychnophora ericoides (Asteraceae) were assessed. The production of the cytotoxic compound cytochalasin H by the fungus Phomopsis sp. FLe6 was remarkably inhibited in solid and liquid co-cultures with the actinobacteria Streptomyces albospinus RLe7. This was a consequence of the fungal growth inhibition caused by antifungal compounds produced by S. albospinus RLe7, including amphotericin B. Cytochalasin H is not toxic to S. albospinus RLe7, suggesting that this microorganism does not require a defense mechanism to prevent the potentially harmful effects of such fungal compound. By exhibiting various competitive phenotypes, these microbes can control each other’s growth when sharing an environment.

New citrinin analogues produced by coculture of the marine algal-derived endophytic fungal strains Aspergillus sydowii EN-534 and Penicillium citrinum EN-535

Ten citrinin analogues (1–10), including a new citrinin dimer (seco-penicitrinol A, 2) and a new citrinin monomer (penicitrinol L, 3), were isolated from the EtOAc extracts of the coculture of two marine algal-derived endophytic fungal strains Aspergillus sydowii EN-534 and Penicillium citrinum EN-535. Their structures were elucidated by detailed analysis of their NMR spectra, ECDs, HRESIMS, optical rotation, and X-ray crystallographic data, and by comparison with literature data as well. The crystal structure of compound 1 was reported for the first time in this paper and resulted in unambiguous confirmation of its absolute configuration as 3R, 4S, 2′R, and 3′S, while the absolute configuration of compound 3 was determined by TDDFT calculations of its ECD spectrum. The antimicrobial and influenza neuraminidase inhibitory activities of compounds 1–10 were evaluated.

Antifungal effects of volatile organic compounds from the endophytic fungus Cryptosporiopsis ericae Cc-HG-7 isolated from Coptis chinensis Franch

ABSTRACTIn this study, 136 strains of endophytic fungi were isolated from the Chinese traditional medicinal plant Coptis chinensis Franch. Of these, 129 strains were classified into 12 different genera according to morphological traits and internal transcribed spacer (ITS) gene sequence analyses. Their antifungal activities were assessed against the following fungi: Magnaporthe oryzae, Pythium graminicola, Cylindrocarpon destructans, Fusarium oxysporum, Cercospora zeae-maydis, Sclerotinia sclerotiorum, Setosphaeria turcica and Botrytis cinerea. Fourteen endophytic strains were active against at least one of the selected fungi. The most active strain Cc-HG-7 identified as Cryptosporiopsis ericae displayed inhibition rates of 81.42% and 72.00%, respectively, against S. sclerotiorum and S. turcica in dual culture technique. The volatile antifungal compounds were identified using headspace solid-phase microextraction, followed by gas chromatography mass spectrometry to investigate the potential biocontrol mechanisms of strain Cc-HG-7. The results suggested that the strain Cc-HG-7 could be a potential agent for the biological control of S. sclerotiorum and S. turcica.