Mycorrhizal symbiosis in Taxus: a review.

Taxus, a genus of conifers known for its medicinal significance, faces various conservation challenges with several species classified under different threat categories by the IUCN. The overharvesting of bark and leaves for the well-known chemotherapy drug paclitaxel has resulted in its population decline. Exploring the mycorrhizal relationship in Taxus is of utmost importance, as mycorrhizal fungi play pivotal roles in nutrition, growth, and ecological resilience. Taxus predominantly associates with arbuscular mycorrhizal fungi (AM), and reports suggest ectomycorrhizal (EM) or dual mycorrhizal associations as well. This review consolidates existing literature on mycorrhizal associations in Taxus species, focusing on structural, physiological, and molecular aspects. AM associations are well-documented in Taxus, influencing plant physiology and propagation. Conversely, EM associations remain relatively understudied, with limited evidence suggesting their occurrence. The review highlights the importance of further research to elucidate dual mycorrhizal associations in Taxus, emphasizing the need for detailed structural and physiological examinations to understand their impact on growth and survival.

Taxoid profile in endophytic fungi isolated from Corylus avellana, introduces potential source for the production of Taxol in semi-synthetic approaches.

Taxol (Paclitaxel) and its derivative taxanes are widely used in chemotherapy and treatment of different types of cancer. Although the extracted taxanes from Taxus sp. are currently used in semi-synthetic production of Taxol, providing alternative always available sources is still a main concern. Due to availability and fast growth rate, microorganisms are much potent alternative sources for taxanes. In the present study, 249 endophytic fungi were isolated from Corylus avellana at six different locations of Iran, among which 18 species were capable to produce taxanes. Genotyping analysis indicated that 17 genera were ascomycetes but only one basidiomycete. Seven taxanes were detected and quantified in solid and suspension cultures by HPLC and their structures were confirmed by LC-Mass analysis. Among endophytes, CA7 had all 7 taxoids and CA1 had the highest Taxol yield. In 78% of endophytes transferring to liquid media was accompanied by increase of taxanes yield and increased taxan production and its release to media up to 90%. Evaluation of cytotoxicity indicated that extracts of all isolated fungi were lethal to MCF7 cells. Since endophytes produced remarkable amounts of taxanes, they can be suggested as alternative inexpensive and easily available resources for Taxol production in semi-synthesis plans.

Endophytic fungus Pseudodidymocyrtis lobariellae KL27 promotes taxol biosynthesis and accumulation in Taxus chinensis.

BACKGROUND: Taxol from Taxus species is a precious drug used for the treatment of cancer and can effectively inhibit the proliferation of cancer cells. However, the growth of Taxus plants is very slow and the content of taxol is quite low. Therefore, it is of great significance to improve the yield of taxol by modern biotechnology without destroying the wild forest resources. Endophytic fungus which symbiosis with their host plants can promote the growth and secondary metabolism of medicinal plants. RESULTS: Here, an endophytic fungus KL27 was isolated from T. chinensis, and identified as Pseudodidymocyrtis lobariellae. The fermentation broth of KL27 (KL27-FB) could significantly promote the accumulation of taxol in needles of T. chinensis, reaching 0.361 ± 0.082 mg/g·DW (dry weight) at 7 days after KL27-FB treatment, which is 3.26-fold increase as compared to the control. The RNA-seq and qRT-PCR showed that KL27-FB could significantly increase the expression of key genes involved in the upstream pathway of terpene synthesis (such as DXS and DXR) and those in the taxol biosynthesis pathway (such as GGPPS, TS, T5OH, TAT, T10OH, T14OH, T2OH, TBT, DBAT and PAM), especially at the early stage of the stimulation. Moreover, the activation of jasmonic acid (JA) biosynthesis and JA signal transduction, and its crosstalk with other hormones, such as gibberellin acid (GA), ethylene (ET) and salicylic acid (SA), explained the elevation of most of the differential expressed genes related to taxol biosynthesis pathway. Moreover, TF (transcriptional factor)-encoding genes, including MYBs, ethylene-responsive transcription factors (ERFs) and basic/helix-loop-helix (bHLH), were detected as differential expressed genes after KL27-FB treatment, further suggested that the regulation of hormone signaling on genes of taxol biosynthesis was mediated by TFs. CONCLUSIONS: Our results indicated that fermentation broth of endophytic fungus KL27-FB could effectively enhance the accumulation of taxol in T. chinensis needles by regulating the phytohormone metabolism and signal transduction and further up-regulating the expression of multiple key genes involved in taxol biosynthesis. This study provides new insight into the regulatory mechanism of how endophytic fungus promotes the production and accumulation of taxol in Taxus sp.

The Research Progress of Taxol in Taxus.

BACKGROUND: Taxus is a valuable woody species with important medicinal value. The bark of Taxus can produce taxol, a natural antineoplastic drug that is widely used in the treatment of breast, ovarian and lung cancers. However, the low content of taxol in the bark of Taxus can not meet the growing clinical demands, so the current research aims at finding ways to increase taxol production. OBJECTIVE: In this review, the research progress of taxol including the factors affecting the taxol content, biosynthesis pathway of taxol, production of taxol in vitro and the application of multi-omics approaches in Taxus as well as future research prospects will be discussed. RESULTS: The taxol content is not only dependent on the species, age and tissues but is also affected by light, moisture levels, temperature, soil fertility and microbes. Most of the enzymes in the taxol biosynthesis pathway have been identified and characterized. Total chemical synthesis, semi-synthesis, plant cell culture and biosynthesis in endophytic fungi have been explored to product taxol. Multi-omics have been used to study Taxus and taxol. CONCLUSION: Further efforts in the identification of unknown enzymes in the taxol biosynthesis pathway, establishment of the genetic transformation system in Taxus and the regulatory mechanism of taxol biosynthesis and Taxus cell growth will play a significant role in improving the yield of taxol in Taxus cells and plants.

Exploiting the Biosynthetic Potency of Taxol from Fungal Endophytes of Conifers Plants; Genome Mining and Metabolic Manipulation.

Endophytic fungi have been considered as a repertoire for bioactive secondary metabolites with potential application in medicine, agriculture and food industry. The biosynthetic pathways by fungal endophytes raise the argument of acquisition of these machineries of such complex metabolites from the plant host. Diterpenoids "Taxol" is the most effective anticancer drug with highest annual sale, since its discovery in 1970 from the Pacific yew tree, Taxus brevifolia. However, the lower yield of Taxol from this natural source (bark of T. brevifolia), availability and vulnerability of this plant to unpredicted fluctuation with the ecological and environmental conditions are the challenges. Endophytic fungi from Taxus spp. opened a new avenue for industrial Taxol production due to their fast growth, cost effectiveness, independence on climatic changes, feasibility of genetic manipulation. However, the anticipation of endophytic fungi for industrial Taxol production has been challenged by the loss of its productivity, due to the metabolic reprograming of cells, downregulating the expression of its encoding genes with subculturing and storage. Thus, the objectives of this review were to (1) Nominate the endophytic fungal isolates with the Taxol producing potency from Taxaceae and Podocarpaceae; (2) Emphasize the different approaches such as molecular manipulation, cultural optimization, co-cultivation for enhancing the Taxol productivities; (3) Accentuate the genome mining of the rate-limiting enzymes for rapid screening the Taxol biosynthetic machinery; (4) Triggering the silenced rate-limiting genes and transcriptional factors to activates the biosynthetic gene cluster of Taxol.

Production of the anticancer drug taxol by the endophytic fungus Epicoccum nigrum TXB502: enhanced production by gamma irradiation mutagenesis and immobilization technique.

Taxol, a phyto-extracted diterpenoid, is the most commercially needed drug in cancer chemotherapy. In spite of the microbial production of taxol being successful and prospective, the reported yields are still not sufficient for large-scale production. Thus, the discovery of new taxol-producing microbial strains and production enhancement methodologies such as process optimization, strain improvement, and immobilization technique are the main objectives. In this paper, a taxol-producing start strain Epicoccum nigrum TXB502 (initial yield 61.35 µg L-1) was isolated from Taxus baccata and identified by morphological and molecular tools. The optimum cultivation and nutritional conditions were assessed by testing one parameter at a time approach that resulted in 88.59% significant production increase. In addition, a stable mutant with improved productivity (40.07% yield increase in comparison with the parent strain) was successfully developed after gamma irradiation mutagenesis of the start strain. The taxol titer was further improved via testing different immobilization carriers for both spores and mycelia of this mutant. Over taxol production was achieved using alginate-immobilized mycelia with the feasibility of conducting six successive production cycles in a semi-continuous form. The final total concentration reached 8187.77 µg taxol 6 L-1 which represents approximately 22-fold increase, as compared to the initial titer of the start strain. These findings can pave the way for the prospective industrial manufacturing of taxol, as the achieved taxol production in this study is the highest reported by academic laboratories for microbial cultures. KEY POINTS: • Discovery of a new taxol-producing endophytic fungus E. nigrum TXB502 strain. • Taxol yield was successfully improved via bioprocess optimization and strain mutagenesis. • Alginate-immobilized mycelia were efficient for a semi-continuous production of taxol. • The final total concentration of taxol showed approximately 22-fold increase as compared to the initial titer.

Rewiring cellular metabolism for heterologous biosynthesis of Taxol.

Taxol is one of the anticancer drugs synthesized naturally in the evergreen Taxus brevifolia forest tree belonging to the yew family (Taxaceae) growing on the Pacific. There are reportedly evidence for treating ovarian, breast and lung cancers through this drug given its unique structural and functional features. Extraction of this drug from yew trees bark is one of the most common ways of producing this drug, but 3000 trees are needed to obtain a kilogram of Taxol. Hence, further attention has recently been attracted to the metabolic engineering strategies, including, engineering cellular metabolism of microorganisms and their optimization. Accordingly, the present paper article was aimed to review recent advances in elevating the production and commercialization of Taxol through metabolic engineering techniques.

Bacillus taxi sp. nov., a novel endophytic bacterium isolated from root of Taxus chinensis (Pilger) Rehd.

A Gram-staining-positive, aerobic, rod-shaped, endospore-forming bacterium, designated strain M5HDSG1-1T, was originally isolated from a surface-sterilized root of Taxus chinensis (Pilger) Rehd. in Guizhou, PR China. This bacterium was tested by a polyphasic approach to determine its taxonomic position. A 16S rRNA gene-based phylogenetic analysis revealed that M5HDSG1-1T had the greatest similarity to the type strain of Bacillus nealsonii DSM 15077T (99.1 %). The average nucleotide identity values between M5HDSG1-1T and Bacillus nealsonii DSM 15077T and Bacillus circulans NBRC 13626T were 73.3 and 72.8 %, respectively. The digital DNA-DNA hybridization values between M5HDSG1-1T and Bacillus nealsonii DSM 15077T and Bacillus circulans NBRC 13626T were 20.1 and 20.6 %, respectively, which were below the recommended thresholds. M5HDSG1-1T grew at a pH range of 6.0-12.0 (optimum, 7.0-8.0), at temperatures between 10 and 45 °C (optimum, 30 °C) and at 0-2 % (w/v) NaCl (optimum, 1 %). Neither substrate nor aerial mycelia was formed, and no diffusible pigments were observed on the media tested. The predominant isoprenoid quinone was menaquinone-7 (MK-7). The major fatty acids were anteiso-C15 : 0, and iso-C15 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid and an unidentified phospholipid. The DNA G+C content was 37.5 mol%. According to the phylogeneic, phenotypic and chemotaxonomic data, M5HDSG1-1T was clearly distinguishable from other species with validly published names in the genus Bacillus and should therefore be classified as representing a novel species, and we suggest the name Bacillus taxi sp. nov. The type strain is M5HDSG1-1T (=JCM 33117T=CGMCC 1.13668T).

Cytotoxic, anti-biofilm and antimicrobial polyketides from the plant associated fungus Chaetosphaeronema achilleae.

From extracts of the plant associated fungus Chaetosphaeronema achilleae collected in Iran, a previously unreported isoindolinone named chaetosisoindolinone (1) and a previously undescribed indanone named chaetosindanone (2) were isolated in addition to five known metabolites, 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (3), vulculic acid (4), 2-(2-acetyl-3-hydroxy-5-methoxyphenyl)acetic acid (5), curvulin (6), and curvulol (7). Their structures were elucidated on the basis of extensive spectroscopic analysis and high-resolution mass spectrometry. The isolated compounds were tested for their antimicrobial, anti-biofilm, and nematicidal activities. Compound 2 exhibited cytotoxicity against the human breast adenocarcinoma MCF-7 cells with an IC50 value of 1.5 µg/mL. Furthermore, compounds 4 and 7 almost completely inhibited biofilm formation in Staphylococcus aureus at 256 µg/mL. Weak antimicrobial activities were also observed for some of the isolated compounds against Mucor hiemalis, Rhodoturula glutinis, Chromobacterium violaceum, and Staphylococcus aureus.

New synergistic co-culture of Corylus avellana cells and Epicoccum nigrum for paclitaxel production.

Paclitaxel is a main impressive chemotherapeutic agent with unique mode of action and broad-spectrum activity against cancers. Hazel (Corylus avellana) is a paclitaxel-producing species through bioprospection. Endophytic fungi have significant roles in plant paclitaxel production. This study evaluated the effect of co-culture of C. avellana cells and paclitaxel-producing endophytic fungus, Epicoccum nigrum strain YEF2 and also the effect of elicitors derived from this fungal strain on paclitaxel production. The results clearly revealed that co-culture of C. avellana cells and E. nigrum was more effective than elicitation of C. avellana cells by only cell extract or culture filtrate of this fungal strain. Co-culture of C. avellana cells and E. nigrum surpassed monocultures in terms of paclitaxel production designating their synergistic interaction potential. Fungal inoculum amount, co-culture establishment time and co-culture period were important factors for achieving the maximum production of paclitaxel in this co-culture system. The highest total yield of paclitaxel (404.5 µg L-1) was produced in co-culture established on 13th day using 3.2% (v/v) of E. nigrum mycelium suspension, which was about 5.5 and 136.6 times that in control cultures of C. avellana cells and E. nigrum, respectively. This is the first report on positive effect of co-culture of paclitaxel-producing endophytic fungus and non-host plant cells for enhancing paclitaxel production.

Enhancing taxol production in a novel endophytic fungus, Aspergillus aculeatinus Tax-6, isolated from Taxus chinensis var. mairei.

Taxol is a curatively effective but rare anti-tumor agent extracted from Taxus (yew) barks; however, the high cost and low production of the extraction method have limited its widespread use. In this study, fungi isolated from Taxus chinensis var. mairei were tested for their ability to produce taxol. High performance liquid chromatography combined with mass spectrometry confirmed that Aspergillus aculeatinus Tax-6, one of the endophytic fungi, could produce taxol in potato dextrose agar liquid medium. NaOAc, Cu2+, and salicylic acid were introduced into the medium to enhance taxol production of strain Tax-6 because NaOAc is an important precursor of taxol, Cu2+ may enhance the activity of oxidase and catalyze the formation of taxol, and salicylic acid could be an elicitor signal. Application of response surface methodology to optimize the culture led to the addition of CuSO4, salicylic acid and sodium acetate at 0.1 mg L-1, 10 mg L-1 and 8 g L-1 to improve taxol yield from 334.92 to 1337.56 µg L-1. Overall, the results of this study confirmed that fungal taxol has the potential to be broadly applied by optimizing the culture conditions.

An endophytic fungus efficiently producing paclitaxel isolated from Taxus wallichiana var. mairei.

Paclitaxel is a medicinal ingredient with high anticancer activity and widely used in hospitals and clinics. In this study, we isolate endophytic fungi efficiently producing paclitaxel from yew for the purpose of paclitaxel manufacture.The bark of Taxus wallichiana var. mairei was surface sterilized and then inoculated in potato dextrose agar culture medium to isolate endophytic fungi. The paclitaxel in the fungal culture was extracted with mixture of chloroform and the same amount of methanol. The content of paclitaxel in the extract was determined and identified with LC-MS. The endophytic fungus efficiently producing paclitaxel was species identified with ITS rDNA and 26S D1/D2 rDNA sequencing.There were 528 endophytic fungal strains were isolated from the bark of T wallichiana var. mairei in total. There was only a strain efficiently producing paclitaxel in these endophytic fungi. The unique strain was identified as Phoma medicaginis. The paclitaxel contents in whole potato dextrose broth (PDB) culture, spent culture medium from this strain and that in dry mycelium is 1.215 mg/L, 0.936 mg/L, and 20 mg/kg, respectively.An endophytic fungus efficiently producing paclitaxel was isolated from T wallichiana var. mairei. This isolated endophytic fungus can be used as a producing strain for paclitaxel manufacture.

Isolation of Taxol-Producing Endophytic Fungi from Iranian Yew Through Novel Molecular Approach and Their Effects on Human Breast Cancer Cell Line.

Taxol or paclitaxel, an approved drug by the Food and Drug Administration, is being used for the treatment of human cancers. This study aimed to isolate and determine different species of native endophytic fungi from Iranian Taxus baccata (yew) plants located in the northern forests of Iran. To do so, a novel molecular screening approach was performed for 50 isolated endophytic fungi through amplification of exon No. 1 of taxadine synthase as a key gene in taxol production pathway. We used effective colony-polymerase chain reaction technique for rapid screening of potent taxol-producing fungi instead of genomic DNA extraction. Production of taxol was performed in batch culture by selected fungi individually and produced taxol was assayed quantitatively by high-performance liquid chromatography using standard taxanes. We found that only six fungi could produce taxol and baccatin III. Interestingly, after 7 days of incubation, the highest level of taxol was found to be 129 and that of baccatin 139.2 mg/kg dw for two native isolated Cladosporium sp. named F1 and F3. The fungal taxols could decrease cell viability in MTT assay same as commercial taxol. The fungal taxols semi-quantitatively showed antimitotic effects on MCF-7 cells as human breast cancer cell line. The expression of bcl-2 anti-apoptotic gene, in contrast to bax pro-apoptotic gene, significantly decreased after treatment by standard and fungal taxols. As fungal taxol was produced simpler than other methods and could significantly affect viability and specific genes expression profile, it is recommended that using of taxol-producing fungi from Iranian yew could be a safe and confident procedure to overcome challenges of using other methods.

[Diversity and bioactivity of actinomycetes isolated from medicinal plant Taxus chinensis and rhizospheric soil].

OBJECTIVE: In order to provide strains with high activity of anti-phytopathogenic fungi and antitumor activity, we studied the diversity and bioactivity of actinomycetes isolated from medicinal plant Taxus chinensis and rhizospheric soil. METHODS: Seven selective media were used to isolate actinomycetes. Experiments of anti-phytopathogenic fungi, cytotoxicity activity, and the 16S rRNA gene sequencing of them were carried out to evaluate the diversity and bioactivity. Strains with high activity were identified. RESULTS: A total of 277 actinomycetes were isolated, of which 111 strains were selected and assigned to 6 suborders, 7 families and 8 genera, in which Streptomyces can be divided into 10 groups. The bioactivity testing results indicated that: 30.9% isolates showed activity against at least one of the 12 phytopathogenic fungi; 44.1% strains and 33.3% strains showed cytotoxicity activity with inhibition rate above 40% against stomach cancer cell line SGC-7901 and lung cancer cell line NCI-H460 respectively. CONCLUSION: Actinomycetes isolated from Taxus chinensis and rhizospheric soil is of high diversity and a good source for the selection of bioactive compounds. Streptomyces KLBMP 2170 is an excellent resource with antifungal and cytotoxicity activity for further studies.

Secondary metabolites of Xylaria sp., an endophytic fungus from Taxus mairei.

One new metabolite 3,7-dimethyl-9-(-2,2,5,5-tetramethyl-1,3-dioxolan-4-yl)nona-1,6-dien-3-ol, together with nine known compounds, were isolated from the strain Xylaria sp., an endophytic fungus of Taxus mairei. Their structures were deduced from 1D and 2D NMR data. In vitro cytotoxicity and antibacterial activity of these compounds were evaluated. Some of them exhibited substantial activity.

Environmental stress and elicitors enhance taxol production by endophytic strains of Paraconiothyrium variabile and Epicoccum nigrum.

This study examined the effect of different elicitors (seven, different concentrations) and environmental factors (water activity (aw), pH) on taxol production by strains of two endophytic fungi, Paraconiothyrium variabile and Epicoccum nigrum, isolated from temperate yew trees. A defined liquid broth medium was modified with elicitors, solute aw depressors at different pH values. For P. variabile, the best elicitor was salicylic acid at 50mg/l which gave a taxol yield of 14.7±4.8µg/l. The study of synergistic effects between elicitor, aw and pH on taxol production showed that the highest yield of taxol (68.9±11.9µg/l) was produced under modified ionic stress of 0.98aw (KCl) at pH 5 when supplemented with 20mg/l of salicylic acid. For E. nigrum, serine was the best elicitor which increased yield significantly (29.6 fold) when KCL was used as the aw depressor (0.98aw) at pH 5.0 with 30mg/l of serine. The maximum taxol yield produced by E. nigrum was 57.1±11.8µg/l. Surface response models were used to build contour maps to determine the conditions for maximum and marginal conditions for taxol yield in relation to the best elicitor and aw, and the best pH for the first time. This will be beneficial for identifying key parameters for improvement of taxol yields by endophytic fungi.

Endophytic fungi associated with Taxus fuana (West Himalayan Yew) of Pakistan: potential bio-resources for cancer chemopreventive agents.

CONTEXT: Endophytic fungi, being a prolific source of bioactive secondary metabolites, are of great interest for natural product discovery. OBJECTIVE: Isolation and partial characterization of endophytic fungi inhabiting the leaves and woody parts of Taxus fuana Nan Li & R.R. Mill. (Taxaceae) and evaluation of biological activity. MATERIALS AND METHODS: Endophytic fungal isolates were identified by molecular analysis of internal transcribed spacer (ITS) regions of 18S rDNA. Extracts of the endophytic fungi cultured on potato dextrose agar and modified medium were evaluated using cancer chemoprevention bioassays [inhibition of TNF-α-induced NFκB, aromatase and inducible nitric oxide synthase (iNOS); induction of quinone reductase 1 (QR1)] and growth inhibition with MCF-7 cells. RESULTS: Nine of 15 fungal isolates were identified as belonging to Epicoccum, Mucor, Penicillium, Chaetomium, Paraconiothriym, Plectania or Trichoderma. Five of the 15 extracts inhibited NFκB activity (IC50 values ranging between 0.18 and 17 µg/mL) and five inhibited iNOS (IC50 values ranging between 0.32 and 12.9 µg/mL). In the aromatase assay, only two isolates mediated inhibition (IC50 values 12.2 and 10.5 µg/mL). With QR1 induction, three extracts exhibited significant activity (concentrations to double activity values ranging between 0.20 and 5.5 µg/mL), and five extracts inhibited the growth of MCF-7 cells (IC50 values ranging from 0.56 to 17.5 µg/mL). Six active cultures were derived from woody parts of the plant material. CONCLUSION: The endophytic fungi studied are capable of producing pharmacologically active natural compounds. In particular, isolates derived from the wood of Taxus fuana should be prioritized for the isolation and characterization of bioactive constituents.

PRODUCTION OF ANTIMICROBIAL PEPTIDES BY EPICOCCUM SP. NFW1: AN ENDOPHYTE OF TAXUS FAUNA.

An endophytic fungus NFWI, possessing antimicrobial activity against bacterial and fungal pathogens, was isolated from indigenous Taxus fauna. Phylogenetic analysis coupled with cultural and morphological characteristics revealed that endophyte NFWI closely resembles Epicoccum sp. It showed optimum growth and antimicrobial activity in mineral salt medium TM, incubation temperature 250C, incubation time 15 days and pH 6.5. Antimicrobial peptides were precipitated with 80% ammonium sulfate and expressed significant inhibitory effect against Staphylococcus aureus (ATCC6538) and Candida albicans (CI.I 4043). It also inhibited growth of Streptomyces 85E in hyphae formation inhibition assay showing potential as protein kinase inhibitor. Gel filtration chromatography on Sephadex G-75, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis resolved the crude precipitate into three fractions of molecular mass 32 kDa, 44 kDa and 70 kDa. The study concludes that endophytic fungi associated with indigenous Taxus species possess promising antimicrobial activities and should be exploited as source of novel antimicrobial agents.

ISOLATION AND IDENTIFICATION OF AN ENDOPHYTIC FUNGUS PRODUCING PACLITAXEL FROM TAXUS WALLICHIANA VAR MAIREI.

The objective of this study was to isolate endophytic fungi producing paclitaxel from yew for the purpose of paclitaxel manufacture. Surface sterilized bark of Taxus wallichiana var. mairei was used as source material and potato dextrose agar culture medium was used in isolation of endophytic fungi. Fungal cultures were extracted with a mixture of chloroform / methanol (1:1, v/v) and the paclitaxel in the extracts was determined and authenticated with LC-MS. An endophytic fungus that produced paclitaxel was identified by ITS rDNA and 26S D1/D2 rDNA sequencing. The results showed that a total of 435 endophytic fungal strains were isolated from T. wallichiana var. mairei and purified. Only one of these strains produced paclitaxel and it belongs to Fusarium. The paclitaxel productivity in whole PDB culture and that in spent culture medium from this strain is 0.0153 mg/L and 0.0119 mg/L respectively. The paclitaxel content in dry mycelium is 0.27 mg/kg. This isolated endophytic fungus produced paclitaxel at a considerable level and shows potentiality as a producing strain for paclitaxel manufacture after strain improvement.

El objetivo de este estudio fue aislar hongos endofíticos productores de paclitaxel a partir de tejo con el propósito de fabricar paclitaxel. Se utilizó la superficie de la corteza esterilizada de Taxus wallichiana var. mairei como material de origen y dextrosa de patata en medio de cultivo de agar para el aislamiento de hongos endófitos. Los cultivos de hongos se extrajeron con una mezcla de cloroformo / metanol (1:1, v/v) y el paclitaxel en los extractos se determinó y autentificó con LC-MS. Un hongo endófito que produjo paclitaxel fue identificado por su ADNr 26S y secuenciación D1/D2 ADNr. Los resultados mostraron que un total de 435 cepas de hongos endófitos se aislaron y purificarón a partir de T. wallichiana var. mairei. Solo una de estas cepas produce paclitaxel y pertenece a Fusarium. La productividad del cultivo de paclitaxel procedente de esta cepa es 0,0153 mg/L y 0,0119 mg/L, respectivamente. El contenido de paclitaxel en micelio seco es 0,27 mg/kg. Este aislado de hongos endófitos produjo paclitaxel a un nivel considerable y muestra potencial como cepa para la fabricación de paclitaxel después de llevar a cabo una mejora de las cepas.

Plant Immunity: A Little Help from Fungal Friends.

Yew trees are famous for production of the anti-cancer drug Taxol (paclitaxel). A new study sheds light on why endophytic fungi that live inside Yew trees also make the same drug.