Search

Two new bioactive trisubstituted furanones, named pinofuranoxins A and B (1 and 2), were isolated from Diplodia sapinea, a worldwide conifer pathogen causing severe disease. Pinofuranoxins A and B were characterized essentially by NMR and HRESIMS spectra, and their relative and absolute configurations were assigned by NOESY experiments and computational analyses of electronic circular dichroism spectra. They induced necrotic lesions on Hedera helix L., Phaseolus vulgaris L., and Quercus ilex L. Compound 1 completely inhibited the growth of Athelia rolfsii and Phytophthora cambivora, while 2 showed antioomycetes activity against P. cambivora. In the Artemia salina assay both toxins showed activity inducing larval mortality.

Monitoring surveys of Phytophthora related diseases in four forest nurseries in Italy revealed the occurrence of fourteen Phytophthora species to be associated with collar and root rot on fourteen plants typical of Mediterranean and alpine regions. In addition, a multilocus phylogeny analysis based on nuclear ITS and ß-tubulin and mitochondrial cox1 sequences, as well as micromorphological features, supported the description of a new species belonging to the phylogenetic clade 7c, Phytophthora mediterranea sp. nov. Phytophthora mediterranea was shown to be associated with collar and root rot symptoms on myrtle seedlings. Phylogenetically, P. mediterranea is closely related to P. cinnamomi but the two species differ in 87 nucleotides in the three studied DNA regions. Morphologically P. mediterranea can be easily distinguished from P. cinnamomi on the basis of its smaller sporangia, colony growth pattern and higher optimum and maximum temperature values. Data from the pathogenicity test showed that P. mediterranea has the potential to threaten the native Mediterranean maquis vegetation. Finally, the discovery of P. cinnamomi in alpine nurseries, confirms the progressive expansion of this species towards cold environments, probably driven by climate change.

Field surveys conducted on nine farms over a 2-year period showed the widespread presence of Phytophthora-related diseases on globe artichoke plants in the main growing area in Sardinia (Italy). Characteristic symptoms included wilting and necrosis of the outermost leaves and dark brown discoloration of stem tissues, as well as root rot. A total of 18 Phytophthora colonies belonging to three species were isolated and characterized. Based on morphological features and ITS sequence data, Phytophthora isolates were identified as P. crassamura (eight isolates) and P. cactorum (four isolates). Six isolates could not be assigned to any formally described species of Phytophthora and are therefore described here as Phytophthora marrasii sp. nov. The ITS phylogeny places P. marrasii in a terminal clade basal to the sister taxa (P. foliorum, P. hibernalis, P. lateralis, and P. ramorum) of the clade 8c. In particular, P. marrasii is phylogenetically related to P. foliorum, a species from which it differs in 62 nucleotides in the ITS region. At the same time, it can easily be distinguished morphologically from P. foliorum mainly because of the low minimum temperature for growth, the bigger and persistent non-papillate sporangia, and smaller oogonia. Pathogenicity tests confirmed that all three Phytophthora species are pathogenic on globe artichokes, which represent a new host for these pathogens.

A new cleistanthane nor-diterpenoid, named olicleistanone (1), was isolated as a racemate from the culture filtrates of Diplodia olivarum an emerging pathogen involved in the aetiology of branch canker and dieback of in several plant species typical of the Mediterranean maquis in Sardinia, Italy. When the fungus was grown in vitro on Czapek medium olicleistanone was isolated together with some already known phytotoxic diterpenoids identified as sphaeropsidins A, C, and G and diplopimarane (2-5). Olicleistanone was characterized by spectroscopic methods (essentially 1D and 2D NMR and HR ESIMS) as 4-ethoxy-6a-methoxy-3,8,8-trimethyl-4,5,8,9,10,11-hexahydrodibenzo[de,g]chromen-7(6aH)-one. When the fungus was grown on mineral salt medium showed to produce (-)-mellein (6), sphaeropsidin A and a very low amount of sphaeropsidin G and diplopimarane. Olicleistanone (1) exhibited remarkable activity against Artemia salina L. (100% larval mortality) at 100 µg/mL. In addition, it did not exhibit phytotoxic, antifungal and antioomycetes activity. Among the metabolites isolated (1-6), the sphaeropsindin A (2) proved to be active in all bioassay performed exhibiting remarkable phytotoxicity on Phaseolus vulgaris L., Juglans regia L. and Quercus suber L. leaves at 1 mg/mL. Moreover, it completely inhibited the mycelial growth of Athelia rolfsii, Diplodia corticola, Phytophthora cambivora and P. lacustris at 200 µg/plug. It was also active in the Artemia salina assay. In this latter assay, diplopimarane (4) and sphaeropsidin G (4) were active (100% larval mortality). Diplopimarane also showed antifungal and antioomycetes activities. Athelia rolfsii was the most sensitive species to diplopimarane. Sphaeropsidin C (3) and (-)-mellein (6) were found to be inactive in all bioassays. Results obtained in this study have allowed us to expand the knowledge on the metabolic profile of Botryosphaeriaceae members and characterize the main secondary metabolites secreted in vitro by D. olivarum for the first time.

In Italy, after the first report in Friuli-Venezia Giulia along the border with Slovenia in 2009, ash dieback has successively been reported in Veneto, Tuscany and Trentino-Alto Adige. Given its alarming expansion in European ash formations along the sub-montane belt of north-eastern Italy and the limited information about the associated fungal microorganisms, since 2017, a study has been conducted in order to isolate and characterize the fungal species involved in the aetiology of the disease. The surveys were conducted in six ash&ndash, maple forests distributed along the Veneto and Friuli-Venezia Giulia pre-Alpine regions (Italy). In each site, the health status of ash trees was assessed and a sample (shoot or branch) with the typical symptoms of the disease was taken from ten trees to isolate the associated pathogens. The fungal colonies developed were identified using morphological features and DNA sequences. The 60 samples processed yielded a total of 109 fungal isolates belonging to 9 families including: Botryosphaeriaceae (62 isolates), Diaporthaceae (18), Nectriaceae (10), Didymellaceae (9), Helotiaceae (5), Diatrypaceae (2), Didymosphaeriaceae (1), Phaeosphaeriaceae (1) and Valsaceae (1). In particular, three species&mdash, Diplodia subglobosa, Diplodia fraxini and Diaporthe eres&mdash, were isolated with high frequency, while Hymenoscyphus fraxineus was isolated from only five plants distributed in four sites. The pathogenicity tests, conducted on 3-year-old seedlings, detached branches (3&ndash, 4 cm diameter), and leaves of Fraxinus excelsior, showed that Diplodia fraxini is the most virulent species and the only one able to reproduce the symptoms observed in nature. Overall, the results obtained emphasize that several fungal pathogens are involved in the aetiology of the disease, many of which belong to the Botryosphaeriaceae family.

Extensive decline and mortality events of alder trees have recently been observed in several riparian ecosystems in Italy. Since there is little information about the aetiology of this disease and given the high ecological relevance of riparian ecosystems, an in-depth study was conducted in three sites spanning from the Mediterranean to Alpine regions. From spring 2019 to spring 2020, 261 samples of bleeding cankers, rhizosphere soil and leaves used as baits along waterways were collected and used for Phytophthora isolation. Based on morphology, colony appearance and DNA sequence data, 10 species belonging to 6 clades were identified. These included P. plurivora (84 isolates), P. pseudocryptogea (50), P. hydropathica (18), P. gonapodyides (14), P. bilorbang (13), P. pseudosyringae (12), P. lacustris (11), P. acerina (7), P. cactorum (1) and one isolate of the hybrid Phytophthora &times, serendipita. In addition, two new Phytophthora species, one of which is described here as Phytophthora alpina sp. nov., were isolated. The pathogenicity of P. alpina and other species obtained from samples collected in the green alder stand was assessed on 3-year-old seedlings. All species proved to be pathogenic on green alder causing symptoms congruent with field observations. Results obtained have allowed us to expand knowledge about alder decline aetiology. The diversity of pathogenicity of Phytophthora species associated with symptomatic alder trees suggested that no single agent is responsible for the disease, but that it is the result of multiple infections of different Phytophthora species, variable in assemblages among sites.

Many pathogens involved in human infection have rapidly increased their antibiotic resistance, reducing the effectiveness of therapies in recent decades. Most of them can form biofilms and effective drugs are not available to treat these formations. Natural products could represent an efficient solution in discovering and developing new drugs to overcome antimicrobial resistance and treat biofilm-related infections. In this study, 20 secondary metabolites produced by pathogenic fungi of forest plants and belonging to diverse classes of naturally occurring compounds were evaluated for the first time against clinical isolates of antibiotic-resistant Gram-negative and Gram-positive bacteria. epi-Epoformin, sphaeropsidone, and sphaeropsidin A showed antimicrobial activity on all test strains. In particular, sphaeropsidin A was effective at low concentrations with Minimum Inhibitory Concentration (MIC) values ranging from 6.25 &mu, g/mL to 12.5 &mu, g/mL against all reference and clinical test strains. Furthermore, sphaeropsidin A at sub-inhibitory concentrations decreased methicillin-resistant S. aureus (MRSA) and P. aeruginosa biofilm formation, as quantified by crystal violet staining. Interestingly, mixtures of sphaeropsidin A and epi-epoformin have shown antimicrobial synergistic effects with a concomitant reduction of cytotoxicity against human immortalized keratinocytes. Our data show that sphaeropsidin A and epi-epoformin possess promising antimicrobial properties.

In this study the production of secondary metabolites by a virulent strain of Sardiniella urbana, a recently described pathogen originally found on declining European hackberry trees in Italy, was investigated for the first time. Chemical analysis of the culture filtrate extracts led to the isolation of three well known compounds as R-(−)-mellein and (3R,4R)-and (3R,4S)-4-hydroxy melleins which were identified by spectroscopic methods (essentially NMR and ESIMS). The isolated compounds were tested for their phytotoxic, antifungal and zootoxic activities. Among them, only R-(−)-mellein was found to be active.

The black-banded oak borer, Coraebus florentinus, is an emerging pest of oak trees in the western Mediterranean region. Larvae of the insect are xylophagous and progressively excavate an annular gallery that interrupts sap flow, resulting in the death of the attacked branches. Until now, limited information has been available regarding the ecological interactions between C. florentinus and the main plant pathogenic fungi involved in the etiology of oak decline. Knowledge of these interactions is important in understanding their impact in natural ecosystems and developing appropriate management strategies. Therefore, in this study, we characterized the fungal communities occurring in the exoskeleton of adults and larvae of C. florentinus and associated with the necrotic wood tissues surrounding the branch galleries of declining oak trees. A total of 29 fungal species were identified based on DNA sequence data and morphological features, of which 14 were from symptomatic woody tissues, six from insect exoskeleton, and nine from both insects and symptomatic wood tissues. The most frequent fungal species, Cryphonectria naterciae (15.9% of isolates), Dothiorella iberica (11.3%), and Diplodia corticola (9.9%), were isolated from both insect and gallery systems. All three species are well-known oak pathogens and are reported here, for the first time, to be associated with C. florentinus. At the same time, 89.6% of the fungal taxa were isolated from one or two sites, highlighting the site-dependence of fungal community assemblages.

A new tetrasubstituted octanoic acid, named hyfraxinic acid (1), was isolated together with known 1-deoxyviridiol (2), viridiol (3), nodulisporiviridin M (4), and demethoxyviridiol (5) from the organic extract of Hymenoscyphus fraxineus responsible for ash (Fraxinus excelsior L.) dieback in Europe. Hyfraxinic acid (1) was characterized, using spectroscopic methods, as 2,4-dihydroxy-7-methyl-6-methyleneoctanoic acid. Furthermore, the advanced Mosher method was used to determine the absolute configuration (3R) of 1-deoxyviridiol. Nodulisporiviridin M (4) was isolated for the first time from H. fraxineus. The phytotoxicity of each compound was tested by a leaf puncture assay on Celtis australis L., Quercus suber L., Hedera elix L., Juglans regia L., and Fraxinus angustifolia L. leaves. Compounds 1, 3, and 5 exhibited remarkable phytotoxicity on all plants tested, inducing necrotic lesions at concentrations of 1.0 and 0.5 mg/mL, while compounds 2 and 4 were found to be inactive in this bioassay. These results could contribute to a deeper understanding of the pathogenicity of H. fraxineus.

From the culture filtrates of Diaporthella cryptica, an emerging hazelnut pathogen, 2-hydroxy-3-phenylpropanoate methyl ester and its 3-(4-hydroxyphenyl) and 3-(1H-indol-3-yl) analogues, named crypticins A-C, were isolated together with the well-known tyrosol. Crypticins A-C were identified by spectroscopic (essentially nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry) methods. The R absolute configuration (AC) of crypticin A was determined by comparing its optical rotation and electronic circular dichroism (ECD) spectrum with those of papuline, the methyl ester of (-)(S)-phenyllactic acid isolated as the main phytotoxin of Pseudomonas syringae pv. papulans, responsible for apple blister spot. The ACs of crypticins B and C were determined by time-dependent density functional theory calculations of their ECD spectra. Papuline and the new metabolites herein isolated, except tyrosol, were tested at 1 mg/mL on cork oak, grapevine, hazelnut, and holm oak leaves using the leaf puncture assay. They were also tested on tomato cuttings at 0.5 and 0.05 mg/mL. In the leaf puncture assay, none of the compounds was found to be active. Crypticin C and papuline were active in the tomato cutting assay. Additionally, crypticin C displayed moderate inhibitory effect against Phytophthora cambivora. © 2018 American Chemical Society.

In this study, a strain (BL 101) of a species of Lasiodiplodia, not yet formally described, which was isolated from declining grapevine plants showing wedge-shaped cankers, was investigated for its ability to produce in vitro bioactive secondary metabolites. From culture filtrates of this strain three jasmonic acid esters, named lasiojasmonates A–C and 16-O-acetylbotryosphaerilactones A and C were isolated together with (1R,2R)-jasmonic acid, its methyl ester, botryosphaerilactone A, (3S,4R,5R)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone and (3R,4S)-botryodiplodin. The structures of lasiojasmonates A–C were established by spectroscopic methods as (1R∗,2R∗,3′S∗,4′R∗,5′R∗)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone, (1R∗,2R∗,3′S∗,4′R∗,5′R∗,10′R∗,12′R∗,13′R∗,14′S∗) and (1R∗,2R∗,3′S∗,4′R∗,5′R∗,10′S∗,12′R∗,13′R∗,14′S∗)-4-(4-hydroxymethyl-3,5-dimethyltetrahydro-furan-2-yloxymethyl)-3,5-dimethyldihydro-2-furanones jasmonates (1, 4 and 5). The structures of 16-O-acetylbotryosphaerilactones A and C were determined by comparison of their spectral data with those of the corresponding acetyl derivatives obtained by acetylation of botryosphaerilactone A. The metabolites isolated, except 4 and 5, were tested at 1 mg/mL on leaves of grapevine cv. Cannonau and cork oak using the leaf puncture assay. They were also tested on detached grapevine leaves at 0.5 mg/mL and tomato cuttings at 0.1 mg/mL. In all phytotoxic assays only jasmonic acid was found to be active. All metabolites were inactive in the zootoxic assay at 50 μg/mL.

Recently oxysporone, a phytotoxic dihydrofuropyranone, was isolated along with two closely related compounds, afritoxinones A and B, from liquid cultures of Diplodia africana, an invasive fungal pathogen of Phoenicean juniper. In this study, eight derivatives were hemisynthesized and assayed for their phytotoxic and antifungal activities in comparison to the parent compound. Each compound was tested on non-host plants and on four destructive plant pathogens such as Athelia rolfsii, Diplodia corticola, Phytophthora cinnamomi and P. plurivora. The results on the phytotoxic activity showed that the dihydrofuropyranone carbon skeleton and both the double bond the hydroxy group of dihydropyran ring appeared to be structural features important in conferring activity. Although the data concerning the antifungal activity did not allow to extract any structure–activity relationships, it should be underlined that the conversion of oxysporone into the corresponding 4-O-benzoyl derivative led to a compound showing a good antifungal activity towards three out of the four organisms tested.

The absolute configuration of sphaeropsidin A was confirmed by X-ray analysis of the toxin and its 6- O - p -bromobenzoyl derivative. Sphaeropsidin A is a tetracyclic pimarane diterpene produced by different pathogens of forest plants belonging to Diplodia spp. This compound has been long known for its phytotoxic, antimicrobial, and insecticidal activities and, more recently, studied for its promising activity against drug-resistant melanoma and kidney cancer. These studies showed that sphaeropsidin A can overcome apoptosis and multidrug resistance in cancer cells through the modulation of ion-transporter activity, which is an emerging approach to cancer treatment. The availability of sphaeropsidin’s X-ray crystal structure could facilitate its further chemical and biological studies in pursuit of its development as an anticancer agent.

A new nor-pimarane diterpene and a new monosubstituted bifuranylone, named sphaeropsidin G (1) and diplobifuranylone D (2), were isolated from the organic extract of Diplodia corticola an oak pathogen together with the already known 4-hydroxyscytalone (3) and diorcinol (4). Sphaeropsidin G and diplobifuranylone D were characterized by using spectroscopic methods as 1,1,7-trimethyl-7-vinyl-2,3,4,4a,4b,5,6,7,10,10a-decahydro-1H-phenanthren-9-one and 5′-(1-hydroxyethyl)-2′,5′-dihydro-2H-[2,2′]bifuranyl-5-one, respectively. The relative configurations of sphaeropsidin G and diplobifuranylone D were assigned by comparison of their spectroscopic properties with those of sphaeropsidin A and diplobifuranylones A–C and confirmed by NOESY spectra. Each compound was tested for phytotoxic, antifungal, antioomycetes and zootoxic activity. Compound 4 was active in all bioassays exhibiting remarkable phytotoxicity on Quercus afares, Quercus suber, Quercus ilex and Celtis australis leaves at 1 mg/mL causing necrotic lesions. It completely inhibited the mycelial growth of Athelia rolfsii, Lasiodiplodia mediterranea and Phytophthora cinnamomi. In the Artemia salina assay, 1, 3 and 4 proved to be active, while 2 was found to be inactive in all bioassays.

Three new lactones and a new fatty acid ester, named sapinofuranones C and D, diplopyrone B, and diplobifuranylone C, respectively, were isolated from Diplodia corticola, together with sphaeropsidins A and C, diplopyrone, diplobifuranylones A and B, diplofuranone A, and the (S,S)-enantiomer of sapinofuranone B. Sapinofuranones C and D, diplopyrone B, and diplobifuranylone C were characterized as (5S)-5-((1,S-1,6-dihydroxyhexa-2,4-dienyl)-dihydrofuran-2-one, 4,5-dihydroxy-deca-6,8-dienoic acid methyl ester, (5S)-5-hydroxy-6-(penta-1,3-dienyl)-5,6-dihydro-pyran-2-one, and 5'-((1R)-1-hydroxyethyl)-2',5'-dihydro-2H-[2,2']bifuranyl-5-one by spectroscopic and chemical methods, respectively. The relative configuration of sapinofuranone C was assigned by X-ray diffraction analysis, whereas its absolute configuration was determined by applying the advanced Mosher's method to its 11-O-p-bromobenzoyl derivative. The same method was used to assign the absolute configuration to C-5 of diplopyrone B and to that of the hydroxyethyl of the side chain of diplobifuranylone C, respectively. The metabolites isolated were tested at 1 mg/mL on leaves of cork oak, grapevine cv. 'Cannonau', and tomato using the leaf puncture assay. They were also tested on tomato cuttings at 0.2, 0.1, and 0.05 mg/mL. Each compound was tested for zootoxic activity on Artemia salina L. larvae. The efficacy of sapinofuranone C and diplopyrone B on three plant pathogens, namely, Athelia rolfsii, Fusarium avenaceum, and Phytophthora nicotianae was also evaluated. In all phytotoxic assays only diplopyrone B was found to be active. It also showed strong inhibition on the vegetative growth of A. rolfsii and P. nicotianae. All metabolites were inactive in the assay performed for the zootoxic activity (A. salina) even at the highest concentration used (200 μg/mL). Diplopyrone B showed a promising antioomycete activity for the control of Phytophthora spp. also taking into account the absence of zootoxic activity.

Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by testing the haustorium-inducing activity of the natural cyclohexene oxides, seven already known and four new hemisynthetic derivatives, in O. cumana, O. crenata, and S. hermonthica, to find a molecular specificity model required for haustorium induction. The results suggested that the haustorium-inducing activity is due to the possibility to convert the natural sphaeropsidone and natural and hemisynthetic derivatives in the corresponding 3-methoxyquinone and that the stereochemistry at C-5 also seems to affect this activity., The work was carried out in the frames of COST Action FA1206 Strigolactones: biological roles and applications. M. Fernández-Aparicio was supported by the European Union, Marie-Curie FP7 COFUND People Programme, through the award of an AgreenSkills fellowship (under grant agreement no. PCOFUND-GA-2010-267196) with additional support from INRA Division “Santé des Plantes et Environment, appel à projets scientifiques 2015 - Catégorie Biocontrôle”.

Sphaeropsidone and episphaeropsidone are two phytotoxic dimedone methyl ethers produced by Diplodia cupressi, the causal agent of a canker disease of cypress in the Mediterranean area. In this study, eight derivatives obtained by chemical modifications and two natural analogues were assayed for phytotoxic and antifungal activities, and a structure-activity relationship was examined. Each compound was tested on nonhost plants and on five fungal pathogenic species belonging to the genus Phytophthora. The results provide insights into structure-activity relationships within these compounds. It was found that the hydroxy group at C-5, the absolute C-5 configuration, the epoxy group, and the C-2 carbonyl group appear to be structural features important in conferring biological activity. The conversion of sphaeropsidone into the corresponding 1,4-dione derivative led to a compound showing greater antifungal activity than its precursor. This finding could be useful in devising new natural fungicides for practical application in agriculture.

Sphaeropsidin A, the main phytotoxin produced by Diplodia cupressi, as well as the two natural analogues sphaeropsidins B and C and 14 derivatives obtained by chemical modifications were assayed for antibacterial activity against Xanthomonas oryzae pv. oryzae, Pseudomonas fuscovaginae, and Burkholderia glumae, the causal agents of severe bacterial rice diseases. The results showed a strong and specific activity of sphaeropsidin A against X. oryzae pv. oryzae, while no activity was observed against the other two pathogens. The results of structure-activity relationship studies showed that structural features important to impart this antibacterial activity are the presence of the C-7 carbonyl group and the hemiketalic lactone functionality. The C-13 vinyl group, the double bond of ring C, and/or the tertiary C-9 hydroxy group, as well as the pimarane arrangement of the tricylic carbon skeleton, were also important for the antibacterial activity. These findings may be useful in designing novel compounds for practical applications in agriculture.

A cork oak endophytic strain of Trichoderma citrinoviride, previously selected for its antagonistic potential against various fungal pathogens involved in oak decline, was screened for the production of bioactive secondary metabolites. From liquid culture a mixture of polypeptide antibiotics (peptaibols) belonging to the paracelsin family was isolated and characterized. This peptide mixture was purified by column chromatography and preparative TLC on silica gel, and separated by analytical HPLC. It was analysed by MALDI-TOF MS and nano-ESI-QTOF MS. Tandem mass experiments were performed to determine the amino acid sequences based on the fragmentation pattern of selected parent ions. The mixture comprised 20-residue peptides with C-terminal phenylalaninol and N-terminal acetylation. Twenty-eight amino acid sequences were identified, and amino acid exchanges were located in positions 6, 9, 12 and 17. Among them, seven sequences are new as compared to those reported in the database specifically for peptaibols and in the literature. In addition, we obtained experimental evidence suggesting the existence of non-covalent dimeric forms (homo- and hetero-) of the various peptaibol species. The peptide mixture showed strong antifungal activity toward seven important forest tree pathogens, and it was highly toxic in an Artemia salina (brine shrimp) bioassay. These results emphasize the cryptic role of endophytic fungi as a source of novel bioactive natural products and biocontrol agents.

A new tetracyclic diterpene having molecular formula C 20 H 28 O 2 and molecular mass of 300 a.m.u., has been isolated from culture filtrate of a strain of Trichoderma viride. The pure compound shows antifungal activity; its structure elucidation was accomplished using 2D-NMR strategies and chemical derivatization.