Towards a phylogenetic classification of Cordyceps: ITS nrDNA sequence data confirm divergent lineages and paraphyly

Differential coexistence of multiple genotypes of Ophiocordyceps sinensis in the stromata, ascocarps and ascospores of natural Cordyceps sinensis

OBJECTIVE

To examine the differential occurrence of Ophiocordyceps sinensis genotypes in the stroma, stromal fertile portion (SFP) densely covered with numerous ascocarps, and ascospores of natural Cordyceps sinensis.

METHODS

Immature and mature C. sinensis specimens were harvested. Mature C. sinensis specimens were continuously cultivated in our laboratory (altitude 2,200 m). The SFPs (with ascocarps) and ascospores of C. sinensis were collected for microscopic and molecular analyses using species-/genotype-specific primers. Sequences of mutant genotypes of O. sinensis were aligned with that of Genotype #1 Hirsutella sinensis and compared phylogenetically using a Bayesian majority-rule method.

RESULTS

Fully and semiejected ascospores were collected from the same specimens. The semiejected ascospores tightly adhered to the surface of the asci as observed by the naked eye and under optical and confocal microscopies. The multicellular heterokaryotic ascospores showed uneven staining of nuclei. The immature and mature stromata, SFPs (with ascocarps) and ascospores were found to differentially contain several GC- and AT-biased genotypes of O. sinensis, Samsoniella hepiali, and an AB067719-type fungus. The genotypes within AT-biased Cluster-A in the Bayesian tree occurred in all compartments of C. sinensis, but those within AT-biased Cluster-B were present in immature and mature stromata and SPFs but absent in the ascospores. Genotype #13 of O. sinensis was present in semi-ejected ascospores and Genotype #14 in fully ejected ascospores. GC-biased Genotypes #13-14 featured large DNA segment substitutions and genetic material recombination between the genomes of the parental fungi (H. sinensis and the AB067719-type fungus). These ascosporic offspring genotypes combined with varying abundances of S. hepiali in the 2 types of ascospores participated in the control of the development, maturation and ejection of the ascospores.

CONCLUSION

Multiple genotypes of O. sinensis coexist differentially in the stromata, SFPs and 2 types of C. sinensis ascospores, along with S. hepiali and the AB067719-type fungus. The fungal components in different combinations and their dynamic alterations in the compartments of C. sinensis during maturation play symbiotic roles in the lifecycle of natural C. sinensis.

Morphology and molecular study of three new Cordycipitoid fungi and its related species collected from Jilin Province, northeast China

Cordyceps species are notable medicinal fungi in China, which are pathogenic on insects and exhibit high biodiversity in tropical and subtropical regions. Recently, three new Cordyceps species, Cordycepschangchunensis and Cordycepsjingyuetanensis growing on pupae of Lepidoptera and Cordycepschangbaiensis growing on larvae of Lepidoptera, were found in Jilin Province, China and are described, based on morphological and ecological characteristics. These three new species are similar to the Cordycepsmilitaris group, but are distinctly distinguishable from the known species. Cordycepschangchunensis, characterised by its small and light yellow to orange stromata which is occasionally forked, covered with white mycelium at the base of stipe, globose to ovoid perithecia, is macroscopically similar to Cordycepsmilitaris. Cordycepschangbaiensis is clearly discriminated from other Cordyceps species by its white to orange and branched stromata, clavate to cylindrical fertile apical portion, immersed and globose to ovoid perithecia. Moreover, unbranched, clavate and orange to light red stromata, almond-shaped to ovoid and immersed perithecia separate Cordycepsjingyuetanensis from other Cordyceps species. nrITS, nrLSU and EF-1α sequences were undertaken and phylogenetic trees, based on Maximum Likelihood and Bayesian Inference analysis showed that the three new species clustered with Cordycepsmilitaris, but formed individual clades, as well as confirmed the results of our morphological study.

Metabolic profiling of natural and cultured Cordyceps by NMR spectroscopy

Cordyceps, a type of Chinese herbal medicine that exhibits anti-angiogenesis and tumor growth suppression effects, has recently gained increasing popularity. However, high-quality, natural Cordyceps, such as Ophiocordyceps sinensis, is very rare and difficult to obtain in large amounts. Cordyceps is cultured instead of harvested from natural sources, but the quality with respect to the ingredients has not been fully studied. In this study, we performed an NMR metabolic profiling of aqueous extracts of Cordyceps without any sample treatment to evaluate the proper species and medium and influence of two different disinfection methods. It was discovered that Cordyceps militaris fungus and silkworm chrysalis medium were suitable for cultivation of Cordyceps. Furthermore, cordycepin, a Cordyceps-specific functional compound, was produced at different growth stages during different cultivation processes, even at the mycelial stage, and was found at three times higher concentrations in cultured C. militaris compared to that in naturally occurring C. militaris.

Study of the whole genome, methylome and transcriptome of Cordyceps militaris

The complete genome of Cordyceps militaris was sequenced using single-molecule real-time (SMRT) sequencing technology at a coverage over 300×. The genome size was 32.57 Mb, and 14 contigs ranging from 0.35 to 4.58 Mb with an N50 of 2.86 Mb were assembled, including 4 contigs with telomeric sequences on both ends and an additional 8 contigs with telomeric sequences on either the 5′ or 3′ end. A methylome database of the genome was constructed using SMRT and m4C and m6A methylated nucleotides, and many unknown modification types were identified. The major m6A methylation motif is GA and GGAG, and the major m4C methylation motif is GC or CG/GC. In the C. militaris genome DNA, there were four types of methylated nucleotides that we confirmed using high-resolution LCMS-IT-TOF. Using PacBio Iso-Seq, a total of 31,133 complete cDNA sequences were obtained in the fruiting body. The conserved domains of the nontranscribed regions of the genome include TATA boxes, which are the initial regions of genome replication. There were 406 structural variants between the HN and CM01 strains, and there were 1,114 structural variants between the HN and ATCC strains.

Transcriptome analysis of Paecilomyces hepiali at different growth stages and culture additives to reveal putative genes in cordycepin biosynthesis

Paecilomyces hepialid (PH) is an endoparasitic fungus of Cordyceps sinensis (CS) and has become a substitute for CS due to their similar pharmacological activities. Because the market demand for CS is difficult to satisfy, and cordycepin, the effective compound of CS, is difficult to industrially produce, we produced 5 samples of PH by culturing for different durations and adding different additives to the culture broth, and detected their cordycepin content with UPLC ESI MS/MS. Then we grouped these cultures into five transcriptome comparisons containing 3 time variable groups and 2 additive variable groups. We used next-generation (NG) sequencing methods to acquire transcriptomic information and investigated the response of gene expression to the additives and the influence of different growth stages. This work will contribute to a better understanding of purine metabolism in PH, and possibly in other Cordyceps species. It will provide a useful resource to further advance transcriptomics studies in Cordyceps species.

Metabolomic profile and nucleoside composition of Cordyceps nidus sp. nov. (Cordycipitaceae): A new source of active compounds

Cordyceps sensu lato is a genus of arthropod-pathogenic fungi, which have been used traditionally as medicinal in Asia. Within the genus, Ophiocordyceps sinensis is the most coveted and expensive species in China. Nevertheless, harvesting wild specimens has become a challenge given that natural populations of the fungus are decreasing and because large-scale culture of it has not yet been achieved. The worldwide demand for products derived from cultivable fungal species with medicinal properties has increased recently. In this study, we propose a new species, Cordyceps nidus, which parasitizes underground nests of trapdoor spiders. This species is phylogenetically related to Cordyceps militaris, Cordyceps pruinosa, and a sibling species of Cordyceps caloceroides. It is found in tropical rainforests from Bolivia, Brazil, Colombia and Ecuador. We also investigated the medicinal potential of this fungus based on its biochemical properties when grown on four different culture media. The metabolic profile particularly that of nucleosides, in polar and non-polar extracts was determined by UPLC, and then correlated to their antimicrobial activity and total phenolic content. The metabolome showed a high and significant dependency on the substrate used for fungal growth. The mass intensities of nucleosides and derivative compounds were higher in natural culture media in comparison to artificial culture media. Among these compounds, cordycepin was the predominant, showing the potential use of this species as an alternative to O. sinensis. Furthermore, methanol fractions showed antimicrobial activity against gram-positive bacteria, and less than 3.00 mg of gallic acid equivalents per g of dried extract were obtained when assessing its total phenolic content by modified Folin-Ciocalteu method. The presence of polyphenols opens the possibility of further exploring the antioxidant capacity and the conditions that may enhance this characteristic. The metabolic composition and biochemical activity indicate potential use of C. nidus in pharmaceutical applications.

The Mechanisms of Pharmacological Activities of Ophiocordyceps sinensis Fungi

The entomopathogenic fungus Ophiocordyceps sinensis, formerly known as Cordyceps sinensis, has long been used as a traditional Chinese medicine for the treatment of many illnesses. In recent years its usage has increased dramatically because of the improvement of people's living standard and the emphasis on health. Such demands have resulted in over-harvesting of this fungus in the wild. Fortunately, scientists have demonstrated that artificially cultured and fermented mycelial products of O. sinensis have similar pharmacological activities to wild O. sinensis. The availability of laboratory cultures will likely to further expand its usage for the treatment of various illnesses. In this review, we summarize recent results on the pharmacological activities of the components of O. sinensis and their putative mechanisms of actions. Copyright © 2016 John Wiley & Sons, Ltd.

Coleopteran and Lepidopteran Hosts of the Entomopathogenic Genus Cordyceps sensu lato

Entomophthoralean and ascomycetous fungi are the two major groups known to parasitize arthropods in almost every terrestrial habitat of the earth. Within Ascomycota, Cordyceps sensu lato is a large genus with more than 400 spp. described on numerous orders of Arthropoda. Among the hosts of Cordyceps, Coleoptera and Lepidoptera are the two major orders. Out of the estimated 200 Cordyceps spp. recorded on coleopteran and lepidopteran hosts, we have documented 92 spp. based on the available information of their host species. Among coleopteran hosts, Scarabaeidae and Elateridae are the two major families. Similarly, among lepidopterans, Hepialidae is the largest host family. Cordyceps militaris shows the widest host range, extending to 2 orders, 13 families, and 32 spp. We hope such accumulative work will be useful as a quick reference for interested biologists, forest ecologists, biocontrol researchers, and fungal and insect taxonomists to apprehend host range and host specificities of Cordyceps fungi.

Optimized extraction, composition, antioxidant and antimicrobial activities of exo and intracellular polysaccharides from submerged culture of Cordyceps cicadae

BACKGROUND

Cordyceps cicadae is known as Jin Chan Hua in Traditional Chinese Medicine and known to possess different pharmacological activities. Presently, it was collected from the wild and isolated. Mycelial culture was optimized for extraction of polysaccharides under submerged culture conditions. Besides antioxidant, antibacterial activities of extracted polysaccharides were tested for first time.

METHODS

Exo-polysaccharides (EPS) and intracellular polysaccharides (IPS) production was tested under different factors (medium capacity, rotation speed, pH, incubation time, temperature, carbon, nitrogen, minerals sources and carbon to nitrogen ratio) by orthogonal experiments using one-factor-at-a-time method. Monosaccharides composition of polysaccharides produced by C. cicadae was determined using high performance liquid chromatography. Antioxidant and antimicrobial activities on eight bacterial strains were checked by different standard procedures.

RESULTS

Factors viz., medium capacity, rotation speed, incubation time, pH and temperature affected the EPS and IPS production under submerged culture conditions. EPS and IPS production was observed to vary with different carbon and nitrogen sources as well as C/N ratio. Glucose was the major component of polysaccharides (63.10 ± 4.15 %). Extracted EPS and IPS showed higher antioxidant potential with significant DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power and iron chelating activity. Antimicrobial activities of EPS and IPS varied among the tested bacterial strains. IPS showed slightly higher inhibition rate to all the tested bacterial strains as compared to EPS. Maximum inhibition zones of IPS (12.9 ± 0.2 mm) and EPS (12.5 ± 0.3 mm) was observed against Pseudomonas aeruginosa at 10 % con. However, both EPS and IPS fractions showed broad spectrum for all the pathogenic microbial strains tested. The MIC of both the extracts ranged from 60-100 mg/mL.

CONCLUSIONS

EPS and IPS production from submerged culture of C. cicadae with significant antioxidant and antibacterial potential can be enhanced with the combination of several factors which can be used for large scale industrial fermentation of C. cicadae.

Optimization, Composition, and Antioxidant Activities of Exo- and Intracellular Polysaccharides in Submerged Culture of Cordyceps gracilis (Grev.) Durieu & Mont

Under present experiments, EPS and IPS production, monosaccharide composition, and antioxidant activities of C. gracilis were studied for the first time under submerged culture conditions. Effect of different factors on polysaccharides production was studied by orthogonal experiments using one-factor-at-a-time method. Incubation of culture in the medium with capacity 200 mL (675.12 ± 5.01 and 385.20 ± 5.01 mg/L), rotation speed 150 rpm (324.62 ± 3.32 and 254.62 ± 4.62 mg/L), 6-day culture incubation time (445.24 ± 1.11, 216.60 ± 1.71 mg/L), pH 6.0 (374.81 ± 2.52 and 219.45 ± 2.59 mg/L), and temperature 23°C (405.24 ± 1.11 and 215.60 ± 1.71 mg/L) produced higher EPS and IPS, respectively. Maximum EPS and IPS production was observed in the medium supplemented with glucose as a carbon source (464.82 ± 2.12 and 264.42 ± 2.62 mg/L) and yeast extract as a nitrogen source (465.21 ± 3.11 and 245.17 ± 3.24 mg/L), respectively. Carbon to nitrogen ratio for maximum EPS and IPS production was observed as 10 : 1 (395.29 ± 2.15 and 235.62 ± 1.40 mg/L), respectively. Glucose was found to be the major monosaccharide (62.15 ± 7.33%). Both EPS and IPS of C. gracilis showed significant DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power, and iron chelating activity.

Novel endophytic lineages of Tolypocladium provide new insights into the ecology and evolution of Cordyceps-like fungi

The objective of this study was to identify a group of unknown endophytic fungal isolates from the living sapwood of wild and planted Hevea (rubber tree) populations. Three novel lineages of Tolypocladium are described based on molecular and morphological data. Findings from this study open a window for novel hypotheses regarding the ecology and role of endophytes within plant communities as well as trait evolution and potential forces driving diversification of Cordyceps-like fungi. This study stresses the importance of integrating asexual and sexual fungal states for a more complete understanding of the natural history of this diverse group. In addition, it highlights the study of fungi in the sapwood of tropical trees as habitat for the discovery of novel fungal lineages and substrate associations.

Non-concerted ITS evolution in fungi, as revealed from the important medicinal fungus Ophiocordyceps sinensis

The internal transcribed spacer (ITS) of nuclear ribosomal DNA (nrDNA) has been widely used as a molecular marker in phylogenetic studies and has been selected as a DNA barcode for fungi. It is generally believed that nrDNA conforms to concerted evolution in most eukaryotes; however, intraindividual-intraspecific polymorphisms of this region were reported in various organisms, suggesting a non-concerted evolutionary process. In Ophiocordyceps sinensis, one of the most valuable medicinal fungi, a remarkable variation of the ITS region has been revealed. Some highly divergent sequences were thought to represent cryptic species, different species or genotypes in previous studies. To clarify the unusual ITS polymorphisms observed in O. sinensis, specific primers were designed to amplify ITS paralogs from pure cultures of both single-ascospore and tissue isolates in this study. All of the available ITS sequences, including those generated by this group and those in GenBank, were analyzed. Several AT-biased ITS paralogs were classified as pseudogenes based on their nucleotide compositions, secondary structures and minimum free energies of their 5.8S rRNAs, substitution rates, phylogenetic positions and gene expression analyses. Furthermore, ITS pseudogenes were amplified with specific primers from 10 of the 28 strains tested, including eight single-ascospore and two tissue isolates. Divergent ITS paralogs were proved to coexist in individual genomes, suggesting a non-concerted mechanism of evolution in the ITS region of O. sinensis. The hypotheses that divergent ITS paralogs represent cryptic or other species or different genotypes were thus rejected.

Development of conventional and nested PCR assays for the detection of Ophiocordyceps sinensis

Ophiocordyceps sinensis, endemic to the Tibetan Plateau, is one of the most important medicinal fungi with a huge economic value. In the present study, specific primer pairs were designed based on a comprehensive ITS sequence dataset of O. sinensis and its related fungi, and tested for specificity and sensitivity through PCR experiments using 27 individuals of O. sinensis from different geographical origins and 40 other related fungal species in terms of phylogeny or ecology. A primer pair highly specific to O. sinensis was obtained, yielding a 275 bp PCR product from all the individuals of O. sinensis but no product from the other fungi tested. The detection limit of the primers was demonstrated to be 10 ng of pure O. sinensis DNA for conventional PCR and 10 pg for nested PCR in a 25 µl reaction system. Soil samples collected from the habitat of O. sinensis were also tested using this PCR assay. The results showed that the primer pair and PCR-based assays developed in this study can be applied to the rapid detection of O. sinensis in its natural habitat.

Polyphasic analysis of Purpureocillium lilacinum isolates from different origins and proposal of the new species Purpureocillium lavendulum

Purpureocillium is a genus recently proposed to accommodate Paecilomyces lilacinus, a well studied species that has biotechnological properties and an ability to cause human infections. Since contradictory data have been reported on the intraspecific genetic variability of P. lilacinum, we have carried out a polyphasic study of a set of clinical and environmental isolates of this species. Detailed morphological examination and sequence analysis of four different loci, including the ribosomal internal transcribed spacer, the domains D1 and D2 of the 28S rDNA, EF-1a and the largest subunit of RNA polymerase II (rpb1), showed that P. lilacinum formed a well supported phylogenetic clade with low intraspecific variability. The new species Purpureocillium lavendulum, which has vinaceous colonies similar to those of P. lilacinum, is proposed. It is characterized by the lack of growth at 35 C, the production of a yellow diffusible pigment and by subglobose or limoniform conidia.

Phylogenetic classification of Cordyceps and the clavicipitaceous fungi

Cordyceps, comprising over 400 species, was historically classified in the Clavicipitaceae, based on cylindrical asci, thickened ascus apices and filiform ascospores, which often disarticulate into part-spores. Cordyceps was characterized by the production of well-developed often stipitate stromata and an ecology as a pathogen of arthropods and Elaphomyces with infrageneric classifications emphasizing arrangement of perithecia, ascospore morphology and host affiliation. To refine the classification of Cordyceps and the Clavicipitaceae, the phylogenetic relationships of 162 taxa were estimated based on analyses consisting of five to seven loci, including the nuclear ribosomal small and large subunits (nrSSU and nrLSU), the elongation factor 1alpha (tef1), the largest and the second largest subunits of RNA polymerase II (rpb1 and rpb2), beta-tubulin (tub), and mitochondrial ATP6 (atp6). Our results strongly support the existence of three clavicipitaceous clades and reject the monophyly of both Cordyceps and Clavicipitaceae. Most diagnostic characters used in current classifications of Cordyceps (e.g., arrangement of perithecia, ascospore fragmentation, etc.) were not supported as being phylogenetically informative; the characters that were most consistent with the phylogeny were texture, pigmentation and morphology of stromata. Therefore, we revise the taxonomy of Cordyceps and the Clavicipitaceae to be consistent with the multi-gene phylogeny. The family Cordycipitaceae is validated based on the type of Cordyceps, C. militaris, and includes most Cordyceps species that possess brightly coloured, fleshy stromata. The new family Ophiocordycipitaceae is proposed based on Ophiocordyceps Petch, which we emend. The majority of species in this family produce darkly pigmented, tough to pliant stromata that often possess aperithecial apices. The new genus Elaphocordyceps is proposed for a subclade of the Ophiocordycipitaceae, which includes all species of Cordyceps that parasitize the fungal genus Elaphomyces and some closely related species that parasitize arthropods. The family Clavicipitaceaes. s. is emended and includes the core clade of grass symbionts (e.g., Balansia, Claviceps, Epichloë, etc.), and the entomopathogenic genus Hypocrella and relatives. In addition, the new genus Metacordyceps is proposed for Cordyceps species that are closely related to the grass symbionts in the Clavicipitaceaes. s.Metacordyceps includes teleomorphs linked to Metarhizium and other closely related anamorphs. Two new species are described, and lists of accepted names for species in Cordyceps, Elaphocordyceps, Metacordyceps and Ophiocordyceps are provided.

Cordyceps militaris (Hypocreales: Cordycipitaceae): transcriptional analysis and molecular characterization of cox1 and group I intron with putative LAGLIDADG endonuclease

The full-length cytochrome c oxidase subunit I gene (cox1) containing a group I intron was isolated from an important medical fungus Cordyceps militaris (Cordycipitaceae). The open reading frame (ORF) of 1,593 nucleotides encoded a predicted protein COX1 of 530 amino acids. The group I intron encoded a putative homing endonuclease (HE) with two LAGLIDADG motifs. RT-PCR and Northern analysis showed a mature transcript of spliced cox1. Both 5'exon-intron and intron-3'exon junctions were also found by RT-PCR, suggesting the possible presence of unspliced cox1 RNA in total RNA. Sequence comparison by BLASTn showed that the coding region of cox1 (CRcox1) of C. militaris had significant similarities to those of related species (such as Cordyceps bassiana and C. brongniartii), while the intron had no significant homologous sequences of Cordycipitaceae fungi in NCBI database. The phylogenetic tree based on the CRcox1 confirmed the present taxonomic status of related species, but the cox1 introns were phylogenetically distinct. Compared to C. bassiana and C. brongniartii, the cox1 intron of C. militaris exhibited specific splicing site and different intronic ORF. The analysis of the folding RNA structures of the known cox1 introns from Cordyceps species showed different base pairs and conserved regions (P1-P10) in their structures. The present results provide useful information on the studies of cox1 intron splicing and Cordyceps evolution.

rDNA-targeted PCR primers and FISH probe in the detection of Ophiocordyceps sinensis hyphae and conidia

Ophiocordyceps sinensis (Berk.) Sung, Sung, Hywel-Jones & Spatafora (syn. Cordyceps sinensis) one of the entomopathogenic fungi, is a rare Traditional Chinese Medicine (TCM) found in the Qinghai-Tibetan Plateau. Polymerase Chain Reaction (PCR) and Fluorescence in situ hybridization (FISH) methods are necessary to identify the mycelia or spores of O. sinensis from its habitat and to monitor its dispersal, colonization and infectivity. To develop both primers and probe specific to O. sinensis, ribosomal DNA (rDNA) amplified with universal primers from O. sinensis genomic DNA and seven closely related fungi were sequenced. According to these sequences, the upper and lower primers (OsT-F and OsT-R) were designed within internal transcribed spacer region 1 (ITS1) and ITS2 and flanked by universal primers ITS5 and ITS4, respectively. The designed primers were used for general PCR, touchdown PCR, or both together with the universal primers for nested-touchdown PCR. The results showed that only the extracted DNA of O. sinensis was specifically amplified. The sensitivity of nested-touchdown PCR with extracted DNA of O. sinensis is as low as 10(-14)g (10 fg) and at least 1000 times higher than the other PCR methods. In addition, Cy5-labeled probe (OsLSU) for cytoplasmic LSU rRNA was hybridized with the ascospores of O. sinensis. It showed a strong red fluorescence throughout the whole cell but did not cross-react with other entomopathogenic fungi. Taken together, these methods were useful for studying the biology and ecology of O. sinensis.

Optimization of selected cultivation parameters for Cordyceps guangdongensis

AIMS

To increase the fruit body production of Cordyceps guangdongensis, selected cultivation conditions, especially nutritional parameters were optimized.

METHODS AND RESULTS

Cordyceps guangdongensis was inoculated on potato dextrose agar slants with pH values from 4.5 to 9.0 and cultivated in artificial media with different carbon and nitrogen supplements. Primordium formation in C. guangdongensis was favoured by slightly acidic conditions. Fruit body yields and biological efficiency (BE) recorded were all highest in cultures of C. guangdongensis supplemented with sucrose and KNO3 as carbon and nitrogen supplements, respectively. Highest fruit body yields and BE values were recorded with C : N ratio of 12 : 1. The optimal medium consisted of (g l(-1)) 20.0 sucrose, 4.0 soya bean powder, 5.0 beef extract and 10.0 KNO3. Cultivation experiments using this medium confirmed its reliability; 18.35% of BE was obtained, compared with a calculated maximum BE of 18.65% based on orthogonal test data.

CONCLUSIONS

Cordyceps guangdongensis preferred sucrose and potassium nitrate as best carbon and nitrogen supplements. It produced satisfying yield of fruit body with optimized medium.

SIGNIFICANCE AND IMPACT OF THE STUDY

Optimized artificial cultivation conditions could promote the yield of C. guangdongensis and decreased the cost of production.

Diversity of acaropathogenic fungi in Poland and other European countries

The occurrence, species diversity and some aspects of taxonomical affinity and host selectivity of acaropathogenic fungi associated with phytophagous, saprotrophic and predacious mites in Poland and other European countries were investigated on wild and cultivated plants, in insect feeding sites under the bark and in decayed wood. From among 33 species of fungi affecting mites only five species of Entomophthorales were separated and the most numerous were Neozygites floridana mostly on Tetranychus urticae, N. abacaridis on a few eriophyid species, and Conidiobolus coronatus attacking gamasid mites most frequently of the genus Dendrolaelaps. The most frequent mite pathogens occurring in mite communities on plants and in wood infested by insects were of the genus Hirsutella. Until now 13 of their form-species have been recognized in these habitats, but only H. kirchneri, H. necatrix and H. thompsonii (including its variety synnematosa) can be treated as exclusive oligophagous pathogens of phytophagous mites, though their potential host range seems to embrace only selected eriophyid or tarsonemid mites. Taxonomical differentiation of fungal strains was based on close morphological observations and molecular analysis of ITS region sequences. Two new species of acaropathogenic fungi were described in these studies. Hirsutella danubiensis sp. nov. was found in the tetranychid T. urticae, whereas H. vandergeesti sp. nov. affected phytoseiid mites of the genera Amblyseius, Neoseiulus, Seiulus and Typhlodromus, and the tarsonemid Tarsonemus lacustris.

Metarhiziopsis microspora gen. et sp. nov. associated with the elongate hemlock scale

A sporodochial fungus collected from the elongate hemlock scale, Fiorinia externa (Ferris) in Coventry, Connecticut, is described. This fungus has characteristics of both Metarhizium and Myrothecium but develops setae surrounding white to buff sporodochia and dry conidia in chains, a combination of characters found in neither genus. Phylogenetic analyses of the complete small subunit ribosomal DNA (ssu), partial ef1-alpha, and complete 5.8S ribosomal DNA and internal transcribed spacers (ITS) 1 and 2 shows that the fungus is allied with a subclade within Cordyceps including the species C. agriota, which places this fungus in the Hypocreales, Clavicipitaceae sensu lato or the newly erected Ophioclavicipitaceae. Morphological observation and molecular analysis indicate that this fungus is sufficiently different from Metarhizium and Myrothecium to warrant the erection of a new anamorphic genus. Therefore Metarhiziopsis microspora gen. et sp. nov. is proposed.

Multigene analysis suggests ecological speciation in the fungal pathogen Claviceps purpurea

Claviceps purpurea is an important pathogen of grasses and source of novel chemical compounds. Three groups within this species (G1, G2 and G3) have been recognized based on habitat association, sclerotia and conidia morphology, as well as alkaloid production. These groups have further been supported by Random Amplification of Polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers, suggesting this species may be more accurately described as a species complex. However, all divergent ecotypes can coexist in sympatric populations with no obvious physical barriers to prevent gene flow. In this study, we used both phylogenetic and population genetic analyses to test for speciation within C. purpurea using DNA sequences from ITS, a RAS-like locus, and a portion of beta-tubulin. The G1 types are significantly divergent from the G2/G3 types based on each of the three loci and the combined dataset, whereas the G2/G3 types are more integrated with one another. Although the G2 and G3 lineages have not diverged as much as the G1 lineage based on DNA sequence data, the use of three DNA loci does reliably separate the G2 and G3 lineages. However, the population genetic analyses strongly suggest little to no gene flow occurring between the different ecotypes, and we argue that this process is driven by adaptations to ecological habitats; G1 isolates are associated with terrestrial grasses, G2 isolates are found in wet and shady environments, and G3 isolates are found in salt marsh habitats.

Accelerated nrDNA evolution and profound AT bias in the medicinal fungus Cordyceps sinensis

Cordyceps sinensis is a reputed medicinal fungus growing parasitically on buried larvae of ghost moths in Asian high-altitude grassland ecosystems. We have analysed the intraspecific ITS nrDNA (ITS1, 5.8S gene, ITS2) variation among 71 sequences of C. sinensis available in EMBL/Genbank. The ITS sequences, submitted to Bayesian ML analyses, were distributed into five groups, referred to as A-E. Nine of the sequences (groups D and E) grouped with distantly related hypocrealean/clavicipitalean taxa and are interpreted as sequences erroneously accessioned under wrong taxon names. The remaining 62 sequences constituted three highly supported clades (groups A-C), that may represent cryptic (phylogenetic) species currently ascribed to C. sinensis. A remarkably high sequence divergence occurred in the 5.8S gene between the three groups. Sequences of groups B and C showed accelerated substitution rates and high AT nucleotide bias. We hypothesize that the accelerated evolution and AT bias have been caused by a shift in life historical attributes or ecology. We also suggest that the recorded differences in medicinal effects among C. sinensis populations may be attributed to the existence of genetically differentiated chemotypes in this morphotaxon.

Development of an expression vector for Metarhizium anisopliae based on the tef-1alpha homologous promoter

The high-conserved translation elongation factor 1 alpha (tef-1alpha) gene from the enthomopathogenic fungus Metarhizium anisopliae was characterized to select the promoter region. A 640-bp DNA fragment upstream to the start codon was employed to drive the expression of the reporter protein sGFP or a dominant selectable marker, the gene bar (resistance to ammonium glufosinate). Transformants carrying this homologous promoter system showed no difference in virulence bioassays against the cattle tick Boophilus microplus comparing to the M. anisopliae wild-type strain. Moreover, GFP fluorescence was detected during tick infection bioassay.

Morphological Characteristics of Conidiogenesis in Cordyceps militaris

Conidial development of Cordyceps militaris was observed from germinating ascospores and vegetative hyphae through light and scanning electron microscopy (SEM). Ascospores were discharged from fresh specimens of C. militaris in sterile water as well as Sabouraud Dextrose agar plus Yeast Extract (SDAY) plates. We observed ascospore germination and conidial formation periodically. Under submerged condition in sterile water, most part-spores germinated unidirectionally and conidia were developed directly from the tips of germinating hyphae of part-spores within 36 h after ascospore discharge, showing microcyclic conidiation. First-formed conidia were cylindrical or clavate followed by globose and ellipsoidal ones. Germination of ascospores and conidial development were observed on SDAY agar by SEM. Slimy heads of conidia on variously arranged phialides, from solitary to whorl, developed 5 days after ascospore discharge. Besides, two distinct types of conidia, elongated pyriform or cylindrical and globose, were observed in the same slimy heads by SEM. Conidia were shown to be uninucleate with 4,6-diamidino-2-phenylindole staining. Conidiogenous cells were more slender than vegetative hyphae, having attenuated tips. Microcyclic conidiation, undifferentiated conidiogenous hyphae (phialides), polymorphic conidia and solitary, opposite to whorled type of phialidic arrangement are reported here as the characteristic features of asexual stage of C. militaris, which can be distinguished from other Cordyceps species.