Marvellous Muscodor spp.: Update on Their Biology and Applications.

Nearly 20 years ago, the first report appeared on the discovery of a novel genus-Muscodor. This organism was isolated as an endophyte from a cinnamon tree that had been introduced to Honduras from Sri Lanka in the early part of the last century. Characteristically, the original Muscodor albus, and all of its species isolated since that time are non-spore producers and each one exudes a characteristic spectrum of volatile bioactive compounds. The majority have a whitish mycelium, which is sometimes coiling, intertwined and decorated with variously shaped structures. Presently, there are at least 22 type species known/documented and each has been described as an endophyte from various plant families with widely varying habitats. An enormous variety of volatile organic compounds (VOCs) are produced by Muscodor spp. and some of these include esters, acids, aldehydes, ketones, aromatics, alkanes, alcohols, nitrosamides and terpenoids. The VOCs are both inhibitory and lethal to a wide variety of fungi and bacteria including some major pathogens of plants and humans. Interestingly, in almost all cases studied, no one compound by itself can mimic the bioactivity of the complete gas mixture, suggesting that the volatiles are acting in a synergistic manner and this has been tested with individual as well as the VOCs in various mixtures and concentrations. This review will discuss some of the recent findings in all aspects of this unique fungal genus whilst at the same time pointing out some of the major questions that remain about its biology, ecology and its applications in agriculture, medicine and other sectors. Most importantly, the authors provide arguments supporting the claim that Muscodor is taxonomically distinct from Induratia, a recently proposed change to its nomenclature.

Genomic and Functional Characterization of the Endophytic Bacillus subtilis 7PJ-16 Strain, a Potential Biocontrol Agent of Mulberry Fruit Sclerotiniose.

Bacillus sp. 7PJ-16, an endophytic bacterium isolated from a healthy mulberry stem and previously identified as Bacillus tequilensis 7PJ-16, exhibits strong antifungal activity and has the capacity to promote plant growth. This strain was studied for its effectiveness as a biocontrol agent to reduce mulberry fruit sclerotiniose in the field and as a growth-promoting agent for mulberry in the greenhouse. In field studies, the cell suspension and supernatant of strain 7PJ-16 exhibited biocontrol efficacy and the lowest disease incidence was reduced down to only 0.80%. In greenhouse experiments, the cell suspension (1.0 × 106 and 1.0 × 105 CFU/mL) and the cell-free supernatant (100-fold and 1000-fold dilution) stimulated mulberry seed germination and promoted mulberry seedling growth. In addition, to accurately identify the 7PJ-16 strain and further explore the mechanisms of its antifungal and growth-promoting properties, the complete genome of this strain was sequenced and annotated. The 7PJ-16 genome is comprised of two circular plasmids and a 4,209,045-bp circular chromosome, containing 4492 protein-coding genes and 116 RNA genes. This strain was ultimately designed as Bacillus subtilis based on core genome sequence analyses using a phylogenomic approach. In this genome, we identified a series of gene clusters that function in the synthesis of non-ribosomal peptides (surfactin, fengycin, bacillibactin, and bacilysin) as well as the ribosome-dependent synthesis of tasA and bacteriocins (subtilin, subtilosin A), which are responsible for the biosynthesis of numerous antimicrobial metabolites. Additionally, several genes with function that promote plant growth, such as indole-3-acetic acid biosynthesis, the production of volatile substances, and siderophores synthesis, were also identified. The information described in this study has established a good foundation for understanding the beneficial interactions between endophytes and host plants, and facilitates the further application of B. subtilis 7PJ-16 as an agricultural biofertilizer and biocontrol agent.

Urnula sp., an Endophyte of Dicksonia antarctica, Making a Fragrant Mixture of Biologically Active Volatile Organic Compounds.

Urnula sp. was isolated as an endophyte of Dicksonia antarctica and identified primarily on the basis of its ITS sequence and morphological features. The anamorphic state of the fungus appeared as a hyphomyceteous-like fungus as based on its features in culture and scanning electron microscopy examination of its spores. On potato dextrose agar (PDA), the organism makes a characteristic fragrance resembling peach pie with vanilla overtones. A GC/MS analysis done on the volatile organic compounds (VOCs) of this organism, trapped by carbotrap methodology, revealed over 150 compounds with high MS matching quality being noted for 44 of these. Some of the most abundantly produced compounds included 4-decene, tridecane, 2-decene (E), 2-dodecene, (Z,E)-alpha-farnesene, butanoic acid, pentyl ester, and 1-hexanol,2-ethyl. In addition, vanillin, methyl vanillin, and many other fragrant substances were noted including isomenthol, pyrazine derivatives, and 3-decanone. In split plate bioassay tests on potato dextrose agar (PDA), Botrytis cinerea, Ceratocystis ulmi, Pythium ultimum, Fusarium solani, and Rhizoctonia solani were inhibited at levels of 24 to 50% of their normal growth on this medium. Bioreactors supporting fungal growth on 50 g of beet pulp waste, using stainless steel carbotraps, yielded over 180 mg of hydrocarbon-based products collected over 6 weeks of incubation. Similarly, because this organism is making one of the largest sets of VOCs as any fungus examined to date, producing many compounds of commercial interest, it has enormous biotechnical potential. The role of the VOCs in the biology and ecology of this endophyte may be related to the antimicrobial activities that they possess.

Fungi as Architects of the Rimstone Dams in Huanglong, NSD, Sichuan, China.

The Huanglong park area of the Sichuan Province of China is a unique scenic area of the world. It is known for its thousands of aquamarine-colored pools that are formed behind naturally formed rimstone dams of travertine (calcite) along a cold water stream. The travertine, based on its crystalline structural analysis, is of biological origin. This makes sense since the temperature of the waters of Huanglong varies from 5 to 7 °C and thus geochemical crystallization does not occur as it does in other locations around the world possessing thermal pools whose structures are primarily formed through cooling processes. Fungi and bacteria were discovered associated with both leaves associated with the calcite dams as well as in the older parts of well-established dams. Several species of Phytium, a phycomycete and an endophyte, accounted for over 45 % of all of the fungi successfully isolated from the well-established dam samples and at least 85 % in the floating leaf samples. Saprolegnia spp. (Phycomycetes) along with Phoma spp. (Ascomycetes) were noted along with Mortierella sp. as other dam-associated fungi. The fungal hyphae observed on dead leaf material as well as in the calcite dams directly served as nucleation points for the formation of crystalline CaCO3. Eventually, these crystals grow large enough to fuse to make calcite plates which form the main structural feature of all of the travertine dams in this area. Interestingly, each of the individual crystals associated with the dams has an associated hole in its core where a fungal hypha used to reside as observed by scanning electron microscopy. While diatoms were present in the analysis, they too seem to contribute to the structure of the dams but in a minor way. The only bacteria isolated from the older dam of this aquatic environment were Pseudomonas spp. and their role in dam formation is uncertain. Huanglong is a unique and beautiful place, and the water features present in this area can definitely be attributed to those fungal architects that encourage calcite crystal formation.

An Insight into the Secondary Metabolism of Muscodor yucatanensis: Small-Molecule Epigenetic Modifiers Induce Expression of Secondary Metabolism-Related Genes and Production of New Metabolites in the Endophyte.

Muscodor spp. are proficient producers of bioactive volatile organic compounds (VOCs) with many potential applications. However, all members of this genus produce varying amounts and types of VOCs which suggests the involvement of epigenetics as a possible explanation. The members of this genus are poorly explored for the production of soluble compounds (extrolites). In this study, the polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes from an endophyte, Muscodor yucatanensis Ni30, were cloned and sequenced. The PKS genes belonged to reduced, partially reduced, non-reduced, and highly reduced subtypes. Strains over-expressing PKS genes were developed through the use of small-molecule epigenetic modifiers (suberoylanilide hydroxamic acid (SAHA) and 5-azacytidine). The putative epigenetic variants of this organism differed considerably from the wild type in morphological features and cultural characteristics as well as metabolites that were produced. Each variant produced a different set of VOCs distinct from the wild type, and several VOCs including methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)hexane-2,4-diol and 2-carboxymethyl-3-n-hexylmaleic appeared in the variant strains, the production of which could be attributed to the activity of otherwise silent PKS genes. The bioactive extrolite brefeldin A was isolated and characterized from the wild type. However, this metabolite was not detected in EV-1, but instead, two other products were isolated and characterized as ergosterol and xylaguaianol C. Hence, M. yucatanensis has the genetic potential to produce several previously undetectable VOCs and organic solvent soluble products. It is also the case that small-molecule epigenetic modifiers can be used to produce stable variant strains of fungi with the potential to produce new molecules. Finally, this work hints to the prospect that the epigenetics of an endophytic microorganism can be influenced by any number of environmental and chemical factors associated with its host plant which may help to explain the enormous chemical diversity of secondary metabolic products found in Muscodor spp.

Characterization of an Endophytic Gloeosporium sp. and Its Novel Bioactivity with "Synergistans".

Gloeosporium sp. (OR-10) was isolated as an endophyte of Tsuga heterophylla (Western hemlock). Both ITS and 18S sequence analyses indicated that the organism best fits either Hypocrea spp. or Trichoderma spp., but neither of these organisms possess conidiophores associated with acervuli, in which case the endophytic isolate OR-10 does. Therefore, the preferred taxonomic assignment was primarily based on the morphological features of the organism as one belonging to the genus Gloeosporium sp. These taxonomic observations clearly point out that limited ITS and 18S sequence information can be misleading when solely used in making taxonomic assignments. The volatile phase of this endophyte was active against a number of plant pathogenic fungi including Phytophthora palmivora, Rhizoctonia solani, Ceratocystis ulmi, Botrytis cinerea, and Verticillium dahliae. Among several terpenes and furans, the most abundantly produced compound in the volatile phase was 6-pentyl-2H-pyran-2-one, a compound possessing antimicrobial activities. When used in conjunction with microliter amounts of any in a series of esters or isobutyric acid, an enhanced inhibitory response occurred with each test fungus that was greater than that exhibited by Gloeosporium sp. or the compounds tested individually. Compounds behaving in this manner are hereby designated "synergistans." An expression of the "median synergistic effect," under prescribed conditions, has been termed the mSE50. This value describes the amount of a potential synergistan that is required to yield an additional median 50% inhibition of a target organism. In this report, the mSE50s are reported for a series of esters and isobutyric acid. The results indicated that isoamyl acetate, allyl acetate, and isobutyric acid generally possessed the lowest mSE50 values. The value and potential importance of these microbial synergistic effects to the microbial environment are also discussed.

Bioprospecting--fuels from fungi.

The world has a continuing demand and utility for liquid fuels to power its societies. The utilization of crude oil based fuels is leading to a dramatic increase in the CO2 content of the atmosphere which is being related to a dangerously warming earth. Having liquid fuels that are derived from biological sources is one solution to this growing problem since the carbon being utilized is only from recycled sources. Presently, the microbes, having the greatest impact on the world's economies, producing liquid fuel are various yeasts producing ethanol. Other microbial sources need to be sought since ethanol is not the most desirable fuel and yeasts require simple sugars to carry out the fermentation processes. Recently, several endophytic fungi have been described that make hydrocarbons with fuel potential (Mycodiesel). Among others the compounds found in the volatile phases of these cultures include alkanes, branched alkanes, cyclohexanes, cyclopentanes, and alkyl alcohols/ketones, benzenes and polyaromatic hydrocarbons. Most importantly, generally these organisms make hydrocarbons while utilizing complex carbohydrates found in all plant-based agricultural wastes. Also discussed in this review is a rationale for finding hydrocarbon producing endophytes as well as examples of other promising hydrocarbon producers-Nodulisporium spp. which make 1,8-cineole and families of other hydrocarbons. Extremely favorable results of engine and fuel testing experiments recently completed on cineole and other products of Nodulisporium sp. are also presented. Finally, there is a brief discussion on the main limiting steps in the domestication of these fungi.

Methods of discovery and techniques to study endophytic fungi producing fuel-related hydrocarbons.

One promising area in the search for renewable bio-fuels is the discovery of microorganisms that produce fuel-related hydrocarbons (mycodiesel) that is in stark contrast to yeast fermentation that utilizes expensive sugars or starch to produce ethanol, which is a proven and useful source of fuel, but by no means is it ideal. Recently, a number of endophytic fungi have been isolated and described that make compounds such as mono- terpenoids, alkanes, cyclohexanes, cyclopentanes, and alkyl alcohols/ketones, benzenes and polyaromatic hydrocarbons. Many of these compounds are either identical to or are closely related to those specific classes of molecules that are found in diesel. Most importantly, these organisms make hydrocarbons while utilizing cellulosic polymers found in all plant-based agricultural wastes. Also discussed are some novel methods and techniques to quantitatively and qualitatively study hydrocarbon production by these microbes. Two models are discussed for identifying potential fuel-related compounds, scaling up production of them and advanced engine testing. Finally, it seems possible that endophytic fungi may have an additional attribute of having contributed to the formation of crude oil in the first place and a description of the paleobiosphere, to test this hypothesis, is in this review.

Functionalized para-substituted benzenes as 1,8-cineole production modulators in an endophytic Nodulisporium species.

A Nodulisporium species (designated Ti-13) was isolated as an endophyte from Cassia fistula. The fungus produces a spectrum of volatile organic compounds (VOCs) that includes ethanol, acetaldehyde and 1,8-cineole as major components. Initial observations of the fungal isolate suggested that reversible attenuation of the organism via removal from the host and successive transfers in pure culture resulted in a 50 % decrease in cineole production unrelated to an overall alteration in fungal growth. A compound (CPM1) was obtained from Betula pendula (silver birch) that increases the production of 1,8-cineole by an attenuated Ti-13 strain to its original level, as measured by a novel bioassay method employing a 1,8-cineole-sensitive fungus (Sclerotinia sclerotiorum). The host plant produces similar compounds possessing this activity. Bioactivity assays with structurally similar compounds such as ferulic acid and gallic acid suggested that the CPM1 does not act as a simple precursor to the biosynthesis of 1,8-cineole. NMR spectroscopy and HPLC-ES-MS indicated that the CPM1 is a para-substituted benzene with alkyl and carboxyl substituents. The VOCs of Ti-13, especially 1,8-cineole, have potential applications in the industrial, fuel and medical fields.

Muscodor albus MOW12 an Endophyte of Piper nigrum L. (Piperaceae) Collected from North East India Produces Volatile Antimicrobials.

Muscodor albus MOW12, an endophytic fungus isolated from Piper nigrum in Mawlong, Meghalaya, India, resembles some cultural and hyphal characteristics of previous isolates of Muscodor sp. In addition, it possesses about 99 % similarity in its ITS rDNA with other M. albus isolates and thus is nicely centered within the genetic tree to other Muscodor spp. This xylariaceae fungus effectively inhibits and kills certain plant pathogenic fungi by virtue of a mixture of volatile compounds that it produces. The majority of these compounds were identified by gas chromatography/mass spectrometry as small molecular weight esters, alcohols, and acids. The main ester components of this isolate of M. albus in its volatile mixture are acetic acid, ethyl ester; propanoic acid, 2-methyl-, methyl ester and acetic acid, 2-methylpropyl ester. This appears to be the first report of any M. albus strain from India.

Collophora aceris, a novel antimycotic producing endophyte associated with Douglas Maple.

A novel endophyte designated Collophora aceris, was obtained from stem tissues of Douglas Maple (Acer glabrum var. douglasii) in a Pacific Northwest temperate rainforest. Colonies were slow growing, white, creamy, moist, and translucent to opaque on potato dextrose agar and other media with few aerial hyphae. It also produced solid, dark sclerotia (200-400 µm) on oatmeal agar and no evidence of pseudopycnidia as per other Collophora spp. Conidia were rod-like in the size ranging from 2.2-8.4 × 0.8-1.8 µm and produced holoblastically on conidiogenous cells by budding with no collarette at the budding site. Phylogenetic analyses, based on 18S rDNA sequence data, showed that C. aceris possessed 99 % similarity to other Collophora spp. However, ITS-5.8S rDNA sequence data indicated that the organism was potentially related to Allantophomopsis spp. Finally, combined morphological, physiological, and molecular genetics data indicated that this organism is most like Collophora spp. but it is distinctly unique when compared to all other fungi in this group. It is to be noted that this is the first report of any member of this genus existing as an endophyte. This fungus makes a wide spectrum antimycotic agent (Collophorin) with biological activity against such pathogenic fungi as Pythium ultimum, Phytophthora cinnamomi, Phytophthora palmivora, and Rhizoctonia solani. Collophorin was purified to homogeneity and shown to have a unique mass of 120.0639, an empirical formula of C8H8O1, and UV absorption bands at 260 and 378 nm. This work also indicates that C. aceris possesses the biological potential to provide protection of its host against an array of common plant pathogens.

The Paleobiosphere: a novel device for the in vivo testing of hydrocarbon producing-utilizing microorganisms.

The construction and testing of a unique instrument, the Paleobiosphere, which mimics some of the conditions of the ancient earth, is described. The instrument provides an experimental testing system for determining if certain microbes, when provided an adequate environment, can degrade biological materials to produce fuel-like hydrocarbons in a relatively short time frame that become trapped by the shale. The conditions selected for testing included a particulate Montana shale (serving as the "Trap Shale"), plant materials (leaves and stems of three extant species whose origins are in the late Cretaceous), a water-circulating system, sterile air, and a specially designed Carbotrap through which all air was passed as exhaust and volatile were hydrocarbons trapped. The fungus for initial testing was Annulohypoxylon sp., isolated as an endophyte of Citrus aurantifolia. It produces, in solid and liquid media, a series of hydrocarbon-like molecules. Some of these including 1,8-cineole, 2-butanone, propanoic acid, 2-methyl-, methyl ester, benzene (1-methylethyl)-, phenylethyl alcohol, benzophenone and azulene, 1,2,3,5,6,7,8,8a-octahydro-1,4-dimethyl-7-(1-methylethenyl), [1S-(1α,7α,8aß)]. These were the key signature compounds used in an initial Paleobiosphere test. After 3 weeks, incubation, the volatiles associated with the harvested "Trap Shale" included each of the signature substances as well as other fungal-associated products: some indanes, benzene derivatives, some cyclohexanes, 3-octanone, naphthalenes and others. The fungus thus produced a series of "Trap Shale" products that were representative of each of the major classes of hydrocarbons in diesel fuel (Mycodiesel). Initial tests with the Paleobiosphere offer some evidence for a possible origin of hydrocarbons trapped in bentonite shale. Thus, with modifications, numerous other tests can also be designed for utilization in the Paleobiosphere.

(6S*)-6-[(1S*,2R*)-1,2-Di-hydroxy-pent-yl]-4-meth-oxy-5,6-di-hydro-2H-pyran-2-one.

The title compound, C11H18O5, was isolated from a liquid culture of Pestalotiopsis sp. In the mol-ecule, the pyran-2-one ring assumes a half-chair conformation. The two terminal C atoms of the pentyl group were refined as disordered over two sets of sites, with refined occupancies of 0.881 (10) and 0.119 (10). In the crystal, mol-ecules are linked via O-H⋯O hydrogen bonds forming a three-dimensional network.

Modulation of volatile organic compound formation in the Mycodiesel-producing endophyte Hypoxylon sp. CI-4.

An endophytic Hypoxylon sp. (strain CI-4) producing a wide spectrum of volatile organic compounds (VOCs), including 1,8-cineole, 1-methyl-1,4-cyclohexadiene and cyclohexane, 1,2,4-tris(methylene), was selected as a candidate for the modulation of VOC production. This was done in order to learn if the production of these and other VOCs can be affected by using agents that may modulate the epigenetics of the fungus. Many of the VOCs made by this organism are of interest because of their high energy densities and thus the potential they might have as Mycodiesel fuels. Strain CI-4 was exposed to the epigenetic modulators suberoylanilide hydroxamic acid (SAHA, a histone deacetylase) and 5-azacytidine (AZA, a DNA methyltransferase inhibitor). After these treatments the organism displayed striking cultural changes, including variations in pigmentation, growth rates and odour, in addition to significant differences in the bioactivities of the VOCs. The resulting variants were designated CI4-B, CI4-AZA and CI4-SAHA. GC/MS analyses of the VOCs produced by the variants showed considerable variation, with the emergence of several compounds not previously observed in the wild-type, particularly an array of tentatively identified terpenes such as α-thujene, sabinene, γ-terpinene, α-terpinolene and ß-selinene, in addition to several primary and secondary alkanes, alkenes, organic acids and derivatives of benzene. Proton transfer reaction mass spectroscopic analyses showed a marked increase in the ratio of ethanol (mass 47) to the total mass of all other ionizable VOCs, from ~0.6 in the untreated strain CI-4 to ~0.8 in CI-4 grown in the presence of AZA. Strain CI4-B was created by exposure of the fungus to 100 µM SAHA; upon removal of the epigenetic modulator from the culture medium, it did not revert to the wild-type phenotype. Results of this study have implications for understanding why there may be a wide range of VOCs found in various isolates of this fungus in nature.

Isolation and characterization of culturable endophytic actinobacteria associated with Artemisia annua L.

Endophytic actinobacteria isolated from Artemisia annua were characterized and evaluated for their bioactivities. A total of 228 isolates representing at least 19 different genera of actinobacteria were obtained and several of them seemed to be novel taxa. An evaluation of antimicrobial activity showed that more isolates possessed activity towards plant pathogens than activity against other pathogenic bacteria or yeasts. High frequencies of PCR amplification were obtained for type I polyketide synthases (PKS-I, 21.1%), type II polyketide synthases (PKS-II, 45.2%) and nonribosomal peptide synthetases (NRPS, 32.5%). The results of herbicidal activity screening indicated that 19 out of 117 samples of fermentation broths completely inhibited the germination of Echinochloa crusgalli. This study indicated that endophytic actinobacteria associated with A. annua are abundant and have potentially beneficial and diverse bioactivities which should be pursued for their biotechnical promise.

In vitro antimicrobial activity of volatile organic compounds from Muscodor crispans against the pathogenic oomycete Pythium insidiosum.

Pythium insidiosum is an oomycete capable of causing a life-threatening disease in humans, called pythiosis. Conventional antifungal drugs are ineffective against P. insidiosum infection. A synthetic mixture of the volatile organic compounds (VOCs) from the endophytic fungus Muscodor crispans strain B23 demonstrates antimicrobial effects against a broad range of human and plant pathogens, including fungi, bacteria, and oomycetes. We studied the in vitro effects of B23 VOCs against 25 human, 1 animal, and 4 environmental isolates of P. insidiosum, compared with a no-drug control. The B23 synthetic mixture, at amounts as low as 2.5 microl, significantly reduced growth of all P. insidiosum isolates by at least 80%. The inhibitory effect of the B23 VOCs was dose-dependent. The growth of all isolates was completely inhibited by a dose of 10.0 microl of B23 VOCs, and all isolates were killed by a dose of 20.0 microl. Synthetic B23 VOCs of M. crispans had inhibitory and lethal effects against all P. insidiosum isolates tested. Further studies are needed to evaluate this mixture for treatment of pythiosis.

3-Carbamoylquinoxalin-1-ium chloride.

The title compound, C(9)H(8)N(3)O(+)·Cl(-), was isolated from a liquid culture of streptomyces sp. In the cation, the ring system makes a dihedral angle of 0.2 (2)° with the amide group. The protonation creating the cation occurs at ome of the N atoms in the quinoxaline ring system. In the crystal, the ions are linked through N-H⋯O and N-H⋯Cl hydrogen bonds, forming a two-dimensional network parallel to (10[Formula: see text]).

An endophytic Phomopsis sp. possessing bioactivity and fuel potential with its volatile organic compounds.

An unusual Phomopsis sp. was isolated as endophyte of Odontoglossum sp. (Orchidaceae), associated with a cloud forest in Northern Ecuador. This fungus produces a unique mixture of volatile organic compounds (VOCs) including sabinene (a monoterpene with a peppery odor) only previously known from higher plants. In addition, some of the other more abundant VOCs recorded by GC/MS in this organism were 1-butanol, 3-methyl; benzeneethanol; 1-propanol, 2-methyl and 2-propanone. The gases of Phomopsis sp. possess antifungal properties and an artificial mixture of the VOCs mimicked the antibiotic effects of this organism with the greatest bioactivity against a wide range of plant pathogenic test fungi including: Pythium, Phytophthora, Sclerotinia, Rhizoctonia, Fusarium, Botrytis, Verticillium, and Colletotrichum. The IC(50) values for the artificial gas mixture of Phomopsis sp. varied between 8 and 25.65 µl/mL. Proton transfer reaction-mass spectrometry monitored the concentration of VOCs emitted by Phomopsis sp. and yielded a total VOC concentration of ca. 18 ppmv in the head space at the seventh day of incubation at 23°C on PDA. As with many VOC-producing endophytes, this Phomopsis sp. did survive and grow in the presence of the inhibitory gases of Muscodor albus. A discussion is presented on the possible involvement of VOC production by the fungus and its role in the biology/ecology of the fungus/plant/environmental relationship.

The diversity and anti-microbial activity of endophytic actinomycetes isolated from medicinal plants in Panxi plateau, China.

Traditional Chinese medicinal plants are sources of biologically active compounds, providing raw material for pharmaceutical, cosmetic and fragrance industries. The endophytes of medicinal plants participate in biochemical pathways and produce analogous or novel bioactive compounds. Panxi plateau in South-west Sichuan in China with its unique geographical and climatological characteristics is a habitat of a great variety of medicinal plants. In this study, 560 endophytic actinomycetes were isolated from 26 medicinal plant species in Panxi plateau. 60 isolates were selected for 16S rDNA-RFLP analysis and 14 representative strains were chosen for 16S rDNA sequencing. According to the phylogenetic analysis, seven isolates were Streptomyces sp., while the remainder belonged to genera Micromonospora, Oerskovia, Nonomuraea, Promicromonospora and Rhodococcus. Antimicrobial activity analysis combined with the results of amplifying genes coding for polyketide synthetase (PKS-I, PKS-II) and nonribosomal peptide synthetase (NRPS) showed that endophytic actinomycetes isolated from medicinal plants in Panxi plateau had broad-spectrum antimicrobial activity and potential natural product diversity, which further proved that endophytic actinomycetes are valuable reservoirs of novel bioactive compounds.