Clinical importance of the genus Trichoderma. A review

Genetic diversity and antagonistic properties of Trichoderma strains from the crop rhizospheres in southern Rajasthan, India

There are fewer studies on Trichoderma diversity in agricultural fields. The rhizosphere of 16 crops was analyzed for Trichoderma species in 7 districts of Rajasthan state of India. Based on DNA sequence of translation elongation factor 1α (tef-1α), and morphological characteristics, 60 isolates were identified as 11 species: Trichoderma brevicompactum, species in Harzianum clade identified as T. afroharzianum, T. inhamatum, T. lentiforme, T. camerunense, T. asperellum, T. asperelloides, T. erinaceum, T. atroviride, T. ghanense, and T. longibrachiatum. T. brevicompactum is the most commonly occurring strain followed by T. afroharzianum. No new species were described in this study. T. lentiforme, showed its first occurrence outside the South American continent. The morphological and cultural characteristics of the major species were observed, described, and illustrated in detail. The isolates were tested for their antagonistic effect against three soilborne plant pathogens fungi: Sclerotium rolfsii, Rhizoctonia solani, and Fusarium verticillioides in plate culture assays. One of the most potent strains was T. afroharzianum BThr29 having a maximum in vitro inhibition of S. rolfsii (76.6%), R. solani (84.8%), and F. verticillioides (85.7%). The potential strain T. afroharzianum BThr29 was also found to be efficient antagonists against soil borne pathogens in in vivo experiment. Such information on crop selectivity, antagonistic properties, and geographic distribution of Trichoderma species will be beneficial for developing efficient Trichoderma-based biocontrol agents.

A collection of Trichoderma isolates from natural environments in Sardinia reveals a complex virome that includes negative-sense fungal viruses with unprecedented genome organizations

Trichoderma genus includes soil-inhabiting fungi that provide important ecosystem services in their interaction with plants and other fungi, as well as biocontrol of fungal plant diseases. A collection of Trichoderma isolates from Sardinia has been previously characterized, but here we selected 113 isolates, representatives of the collection, and characterized their viral components. We carried out high-throughput sequencing of ribosome-depleted total RNA following a bioinformatics pipeline that detects virus-derived RNA-directed RNA polymerases (RdRps) and other conserved viral protein sequences. This pipeline detected seventeen viral RdRps with two of them corresponding to viruses already detected in other regions of the world and the remaining fifteen representing isolates of new putative virus species. Surprisingly, eight of them are from new negative-sense RNA viruses, a first in the genus Trichoderma. Among them is a cogu-like virus, closely related to plant-infecting viruses. Regarding the positive-sense viruses, we report the presence of an 'ormycovirus' belonging to a recently characterized group of bisegmented single-stranded RNA viruses with uncertain phylogenetic assignment. Finally, for the first time, we report a bisegmented member of Mononegavirales which infects fungi. The proteins encoded by the second genomic RNA of this virus were used to re-evaluate several viruses in the Penicillimonavirus and Plasmopamonavirus genera, here shown to be bisegmented and encoding a conserved polypeptide that has structural conservation with the nucleocapsid domain of rhabdoviruses.

Trichoderma: a multipurpose, plant-beneficial microorganism for eco-sustainable agriculture

Trichoderma is a cosmopolitan and opportunistic ascomycete fungal genus including species that are of interest to agriculture as direct biological control agents of phytopathogens. Trichoderma utilizes direct antagonism and competition, particularly in the rhizosphere, where it modulates the composition of and interactions with other microorganisms. In its colonization of plants, on the roots or as an endophyte, Trichoderma has evolved the capacity to communicate with the plant and produce numerous multifaceted benefits to its host. The intricacy of this plant-microorganism association has stimulated a marked interest in research on Trichoderma, ranging from its capacity as a plant growth promoter to its ability to prime local and systemic defence responses against biotic and abiotic stresses and to activate transcriptional memory affecting plant responses to future stresses. This Review discusses the ecophysiology and diversity of Trichoderma and the complexity of its relationships in the agroecosystem, highlighting its potential as a direct and indirect biological control agent, biostimulant and biofertilizer, which are useful multipurpose properties for agricultural applications. We also highlight how the present legislative framework might accommodate the demonstrated evidence of Trichoderma proficiency as a plant-beneficial microorganism contributing towards eco-sustainable agriculture.

Structure-activity correlations for peptaibols obtained from clade Longibrachiatum of Trichoderma: A combined experimental and computational approach

Integrated disease management and plant protection have been discussed with much fervor in the past decade due to the rising environmental concerns of using industrially produced pesticides. Members of the genus Trichoderma are a subject of considerable research today due to their several properties as biocontrol agents. In our study, the peptaibol production of Trichoderma longibrachiatum SZMC 1775, T. longibrachiatum f. bissettii SZMC 12546, T. reesei SZMC 22616, T. reesei SZMC 22614, T. saturnisporum SZMC 22606 and T. effusum SZMC 22611 were investigated to elucidate structure-activity relationships (SARs) between the properties of peptaibols and their 3D structures. The effects of peptaibol mixtures obtained from every Trichoderma strain were examined against nine commonly known bacteria. The lowest minimum inhibitory concentrations (MIC, mg ml-1) were exerted by T. longibrachiatum f. bissettii SZMC 12546 against Gram-positive bacteria, which was also able to inhibit the plant pathogenic Gram-negative Rhizobium radiobacter. Accelerated molecular dynamics (aMD) simulations were performed in aqueous solvent to explore the folding dynamics of 12 selected peptaibol sequences. The most characteristic difference between the peptaibols from group A and B relies in the 'Gly-Leu-Aib-Pro' and 'Gly-Aib-Aib-Pro' motifs ('Aib' stands for α-aminoisobutyric acid), which imparted a significant effect on the folding dynamics in water and might be correlated with their expressed bioactivity. In our aMD simulation experiments, Group A peptaibols showed more restricted folding dynamics with well-folded helical conformations as the most stable representative structures. This structural stability and dynamics may contribute to their bioactivity against the selected bacterial species.

Trichoderma after crossing kingdoms: infections in human populations

Trichoderma is a saprophytic fungus that is used worldwide as a biocontrol and biofertilizer agent. Although considered nonpathogenic until recently, reports of human infections produced by members of the Trichoderma genus are increasing. Numerous sources of infection were proposed based upon patient data and phylogenetic analysis, including air, agriculture, and healthcare facilities, but the deficit of knowledge concerning Trichoderma infections makes patient treatment difficult. These issues are compounded by isolates that present profiles which exhibit high minimum inhibitory concentration values to available antifungal drugs. The aim of this review is to present the global distribution and sources of infections that affect both immunocompetent and immunocompromised hosts, clinical features, therapeutic strategies that are used to treat patients, as well as highlighting treatments with the best responses. In addition, the antifungal susceptibility profiles of Trichoderma isolates that have emerged in recent decades were examined and which antifungal drugs need to be further evaluated as potential candidates to treat Trichoderma infections are also indicated.

Aspergillus Was the Dominant Genus Found during Diversity Tracking of Potentially Pathogenic Indoor Fungal Isolates

Viable airborne pathogenic fungi represent a potential health hazard when exposing vulnerable persons in quantities exceeding their resilience. In this study, 284 indoor fungal isolates from a strain collection of indoor fungi were screened for pathogenic potential through the ability to grow in neutral pH at 37 °C and 30 °C. The isolates were collected from 20 locations including 14 problematic and 6 non-problematic ordinary buildings. Out of the screened isolates, 170 isolates were unable to grow at 37 °C, whereas 67 isolates growing at pH 7.2 at 37 °C were considered as potential opportunistic pathogens. Forty-seven isolates growing at 30 °C but not at 37 °C were considered as less likely pathogens. Out of these categories, 33 and 33 strains, respectively, were identified to the species level. The problematic buildings included known opportunistic pathogens: Aspergillus calidoustus, Trichoderma longibrachiatum, Rhizopus arrhizus and Paecilomyces variotii, as well as less likely pathogens: Aspergillus versicolor, Chaetomium cochliodes, Chaetomium globosum and Chaetomium rectangulare. Opportunistic pathogens such as Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger and Aspergillus tubingensis and less likely pathogens such as Aspergillus westerdijkiae, Chaetomium globosum and Dichotomopilus finlandicus were isolated both from ordinary and from problematic buildings. Aspergillus was the dominant, most diverse genus found during screening for potentially pathogenic isolates in the indoor strain collection. Studies on Aspergillus niger and Aspergillus calidodoustus revealed that tolerance to cleaning chemicals may contribute to the adaptation of Aspergillus species to indoor environments.

Trichoderma species from plant and soil: An excellent resource for biosynthesis of terpenoids with versatile bioactivities

BACKGROUND

Trichoderma species are rich source of bioactive secondary metabolites. In the past decades, a series of secondary metabolites were reported from different Trichoderma fungi, among which terpenoids possessing versatile structural diversities and extensive pharmacological activities are one of the particularly important categories.

AIM OF REVIEW

The review aims to summarize the terpenoids isolated from Trichoderma species regarding their structural diversities, biological activities, and promising biosynthetic potentials.

KEY SCIENTIFIC CONCEPTS OF REVIEW

So far, a total of 253 terpenoids, including 202 sesquiterpenes, 48 diterpenes, 2 monoterpenes and 1 meroterpenoid, were isolated and identified from Trichoderma species between 1948 and 2022. Pharmacological investigations of Trichoderma terpenoids mainly focused on their antibacterial activities, antifungal activities, inhibitory activities on marine plankton species and cytotoxic activities, indicating that Trichoderma species are important microbial agents for drug discovery and environmentally friendly agrochemicals development. Intriguing chemistry and enzymology involved in the biosynthesis of Trichoderma terpenoids were also presented to facilitate further precise genome mining-guided novel structure discovery. Taken together, the abundance of novel skeletons, bioactivities and biosynthetic potentials presents new opportunities for drug and agrochemicals discovery, genome mining and enzymology exploration from Trichoderma species. The work will provide references for the profound study of terpenoids derived from Trichoderma, and facilitate further studies on Trichoderma species in the areas of chemistry, medicine, agriculture and microbiology.

Taxonomy and control of Trichoderma hymenopellicola sp. nov. responsible for the first green mold disease on Hymenopellis raphanipes

Trichoderma spp. are a group of widespread fungi with important applications in many aspects of human life, but they are also pathogens that cause green mold disease on mushrooms. During a survey of mushroom cultivation in Guizhou, China, five strains of Trichoderma from three different localities were isolated from soil in mushroom bags of Hymenopellis raphanipes. The typical morphology of having gregarious, reddish stromata and gregarious phialides and the results of phylogenetic analyses based on a combined dataset of RPB2, TEF, and ITS gene sequences demonstrated that these green-spored Trichoderma belong to a new taxon, Trichoderma hymenopellicola. Pathogenicity tests by covering fungal mycelial blocks or soil mixed with spore suspension in mushroom bags showed similar symptoms to those in the field, and the same fungal pathogen had been observed and re-isolated from these symptoms, which fulfill Koch’s postulates. A primary screening test of nine common fungicides indicated that prochloraz-manganese chloride complex and propiconazole are the top two effective fungicides inhibiting the pathogen, whereas the former was further indicated as a suitable fungicide to control Trichoderma hymenopellicola, with a high inhibition ratio to the pathogen and low toxicity to the mushroom.

Trichoderma - genomes and genomics as treasure troves for research towards biology, biotechnology and agriculture

The genus Trichoderma is among the best studied groups of filamentous fungi, largely because of its high relevance in applications from agriculture to enzyme biosynthesis to biofuel production. However, the physiological competences of these fungi, that led to these beneficial applications are intriguing also from a scientific and ecological point of view. This review therefore summarizes recent developments in studies of fungal genomes, updates on previously started genome annotation efforts and novel discoveries as well as efforts towards bioprospecting for enzymes and bioactive compounds such as cellulases, enzymes degrading xenobiotics and metabolites with potential pharmaceutical value. Thereby insights are provided into genomes, mitochondrial genomes and genomes of mycoviruses of Trichoderma strains relevant for enzyme production, biocontrol and mycoremediation. In several cases, production of bioactive compounds could be associated with responsible genes or clusters and bioremediation capabilities could be supported or predicted using genome information. Insights into evolution of the genus Trichoderma revealed large scale horizontal gene transfer, predominantly of CAZyme genes, but also secondary metabolite clusters. Investigation of sexual development showed that Trichoderma species are competent of repeat induced point mutation (RIP) and in some cases, segmental aneuploidy was observed. Some random mutants finally gave away their crucial mutations like T. reesei QM9978 and QM9136 and the fertility defect of QM6a was traced back to its gene defect. The Trichoderma core genome was narrowed down to 7000 genes and gene clustering was investigated in the genomes of multiple species. Finally, recent developments in application of CRISPR/Cas9 in Trichoderma, cloning and expression strategies for the workhorse T. reesei as well as the use genome mining tools for bioprospecting Trichoderma are highlighted. The intriguing new findings on evolution, genomics and physiology highlight emerging trends and illustrate worthwhile perspectives in diverse fields of research with Trichoderma.

The Biocontrol Potential of Endophytic Trichoderma Fungi Isolated from Hungarian Grapevines. Part I. Isolation, Identification and In Vitro Studies

This paper reports on the identification and in vitro characterization of several Trichoderma strains isolated from the Tokaj Wine Region in North-East Hungary. Ten isolates were analyzed and found to consist of six individual species—T. gamsii, T. orientale, T. simmonsii, T. afroharzianum, T. atrobrunneum and T. harzianum sensu stricto. The growth potential of the strains was assessed at a range of temperatures. We also report here on the in vitro biocontrol properties and fungicide tolerance of the most promising strains.

Trichoderma longibrachiatum and Aspergillus fischeri Infection as a Cause of Skin Graft Failure in a Patient with Critical Burns after Liver Transplantation

Infectious complications are responsible for the majority of mortalities and morbidities of patients with critical burns. Although bacteria are the predominant etiological agents in such patients, yeasts and fungi have become relatively common causes of infections over the last decade. Here, we report a case of a young man with critical burns on 88% TBSA (total body surface area) arising as a part of polytrauma. The patient's history of orthotopic liver transplantation associated with the patient's need to use combined immunosuppressant therapy was an additional complication. Due to deep burns in the forearm region, we have (after a suitable wound bed preparation) applied a new bi-layered dermal substitute. The patient, however, developed a combined fungal infection in the region of this dermal substitute caused by Trichoderma longibrachiatum and Aspergillus fischeri (the first case ever reported). The infection caused the loss of the split-thickness skin grafts (STSGs); we had to perform repeated hydrosurgical and mechanical debridement and a systemic antifungal treatment prior to re-application of the STSGs. The subsequent skin transplant was successful.

Exposition to Biological Control Agent Trichoderma stromaticum Increases the Development of Cancer in Mice Injected With Murine Melanoma

Biological control agents (BCA) are an alternative to chemical pesticides and an emerging strategy to safely eliminate plant pathogens. Trichoderma spp. are the most common fungi used as BCAs. They produce spores that are released into the air and can potentially interact with immune system of mammals. We previously showed that Trichoderma affects expression of genes encoding pattern recognition receptors (PRRs) and cytokines in mice. PRRs are involved in the recognition of microorganisms and can lead to pro-tumoral signaling. Here, we evaluated if mice injected with low doses of murine melanoma exhibited increased development of lung tumor when treated with conidia of T. stromaticum. Mice treated with T. stromaticum and inoculated with B16-F10 melanoma cells exhibited significant increase in tumor uptake (p = 0.006) and increased number of visible nodules in the lungs (p = 0.015). We also analyzed mRNA expression levels of genes encoding PRRs in lung of mice exposed to T. stromaticum and demonstrated that mice treated with T. stromaticum conidia exhibited lower expression levels of Clec7a and increased expression of Tlr4 (toll like receptor 4) compared to non-treated controls. The expression levels of Clec7a and Tlr2 were increased in mice treated with T. stromaticum and inoculated with murine melanoma compared to controls only inoculated with melanoma. Our results demonstrate that intranasal exposition to T. stromaticum increases tumor in the B16-F10 model, which may raise concerns regarding the safety of its use in agriculture.

Structural Diversity and Bioactivities of Peptaibol Compounds From the Longibrachiatum Clade of the Filamentous Fungal Genus Trichoderma

This study examined the structural diversity and bioactivity of peptaibol compounds produced by species from the phylogenetically separated Longibrachiatum Clade of the filamentous fungal genus Trichoderma, which contains several biotechnologically, agriculturally and clinically important species. HPLC-ESI-MS investigations of crude extracts from 17 species of the Longibrachiatum Clade (T. aethiopicum, T. andinense, T. capillare, T. citrinoviride, T. effusum, T. flagellatum, T. ghanense, T. konilangbra, T. longibrachiatum, T. novae-zelandiae, T. pinnatum, T. parareesei, T. pseudokoningii, T. reesei, T. saturnisporum, T. sinensis, and T. orientale) revealed several new and recurrent 20-residue peptaibols related to trichobrachins, paracelsins, suzukacillins, saturnisporins, trichoaureocins, trichocellins, longibrachins, hyporientalins, trichokonins, trilongins, metanicins, trichosporins, gliodeliquescins, alamethicins and hypophellins, as well as eight 19-residue sequences from a new subfamily of peptaibols named brevicelsins. Non-ribosomal peptide synthetase genes were mined from the available genome sequences of the Longibrachiatum Clade. Their annotation and product prediction were performed in silico and revealed full agreement in 11 out of 20 positions regarding the amino acids predicted based on the signature sequences and the detected amino acids incorporated. Molecular dynamics simulations were performed for structural characterization of four selected peptaibol sequences: paracelsins B, H and their 19-residue counterparts brevicelsins I and IV. Loss of position R6 in brevicelsins resulted in smaller helical structures with higher atomic fluctuation for every residue than the structures formed by paracelsins. We observed the formation of highly bent, almost hairpin-like, helical structures throughout the trajectory, along with linear conformation. Bioactivity tests were performed on the purified peptaibol extract of T. reesei on clinically and phytopathologically important filamentous fungi, mammalian cells, and Arabidopsis thaliana seedlings. Porcine kidney cells and boar spermatozoa proved to be sensitive to the purified peptaibol extract. Peptaibol concentrations ≥0.3 mg ml-1 deterred the growth of A. thaliana. However, negative effects to plants were not detected at concentrations below 0.1 mg ml-1, which could still inhibit plant pathogenic filamentous fungi, suggesting that those peptaibols reported here may have applications for plant protection.

Microbial biomarkers of common tongue coatings in patients with gastric cancer

PURPOSE

The study aims to explore the characteristic microorganisms of the common tongue coatings in patients with gastric cancer (GC).

METHODS

A total of 115 GC patients were assigned to four groups: White-thin coating (W-thin) group, White-thick coating (W-thick) group, Yellow-thin coating (Y-thin) group and Yellow-thick coating (Y-thick) group. Thirty-five healthy volunteers with White-thin coating were recruit as controls. High-throughput sequencing was used to describe the microbial community of the tongue coatings based on 16S rRNA and 18S rRNA genes. Multi-factors statistical analysis was carried out to present the microbial biomarkers of the tongue coating in GC patients.

RESULTS

At bacterial phylum level, Saccharibacteria had higher relative abundance in W-thick group than W-thin group, Proteobacteria was more abundant in W-thin group than Y-thick group and less abundant in Y-thick group than Y-thin group. At fungal genus level, Guehomyces and Aspergillus presented to be significantly different among the common tongue coatings. Forteen significantly increased taxa were sorted out as the microbial biomarkers of common tongue coatings by LEfSe and ROC analysis. At species level, bacterial Capnocytophaga leadbetteri and fungal Ampelomyces_sp_IRAN_1 may be the potential biomarkers of W-thin coating, four bacterial species (Megasphaera micronuciformis, Selenomonas sputigena ATCC 35185, Acinetobacter ursingii, Prevotella maculosa) may be the potential biomarkers of W-thick coating. In general, the white coatings held more complex commensal relationship than the yellow coatings.

CONCLUSION

The common tongue coating owned characteristic microorganisms and special commensal relationship in the GC patients.

Fungal Contaminants in Drinking Water Regulation? A Tale of Ecology, Exposure, Purification and Clinical Relevance

Microbiological drinking water safety is traditionally monitored mainly by bacterial parameters that indicate faecal contamination. These parameters correlate with gastro-intestinal illness, despite the fact that viral agents, resulting from faecal contamination, are usually the cause. This leaves behind microbes that can cause illness other than gastro-intestinal and several emerging pathogens, disregarding non-endemic microbial contaminants and those with recent pathogenic activity reported. This white paper focuses on one group of contaminants known to cause allergies, opportunistic infections and intoxications: Fungi. It presents a review on their occurrence, ecology and physiology. Additionally, factors contributing to their presence in water distribution systems, as well as their effect on water quality are discussed. Presence of opportunistic and pathogenic fungi in drinking water can pose a health risk to consumers due to daily contact with water, via several exposure points, such as drinking and showering. The clinical relevance and influence on human health of the most common fungal contaminants in drinking water is discussed. Our goal with this paper is to place fungal contaminants on the roadmap of evidence based and emerging threats for drinking water quality safety regulations.

Two new hyaline-ascospored species of Trichoderma and their phylogenetic positions

Collections of hypocrealean fungi found on decaying wood in subtropical regions of China were examined. Two new species, Trichoderma confluens and T. hubeiense, were discovered and are described. Trichoderma confluens is characterized by its widely effuse to rarely pulvinate, yellow stromata with densely disposed yellowish brown ostioles, simple acremonium- to verticillium-like conidiophores, hyaline conidia and multiform chlamydospores. Trichoderma hubeiense has pulvinate, grayish yellow stromata with brownish ostioles, trichoderma- to verticillium-like conidiophores and hyaline conidia. The phylogenetic positions of the two fungi were investigated based on sequence analyses of RNA polymerase II subunit b and translation elongation factor 1-α genes. The results indicate that T. confluens belongs to the Hypocreanum clade and is associated with but clearly separated from T. applanatum and T. decipiens. Trichoderma hubeiense belongs to the Polysporum clade and related to T. bavaricum but obviously differs from other members of the clade in sequence data. Morphological distinctions between the new species and their close relatives are noted and discussed.

Three new species of Trichoderma with hyaline ascospores from China

Collections of Trichoderma having hyaline ascospores from different areas of China were examined. Using combined analyses of morphological data, culture characters and phylogenetic information based on rDNA sequences of partial nuc translation elongation factor 1-α encoding gene (TEF1-α) and the gene encoding the second largest nuc RNA polymerase subunit (RPB2), three new species, Trichoderma applanatum, T. oligosporum and T. sinoluteum, were discovered and are described. Trichoderma applanatum produces continuous flat to pulvinate, white to cream stromata with dense orange or pale brown ostioles, and simple acremonium-like to verticillium-like conidiophores, belongs to the Hypocreanum clade and is closely related to T. decipiens. Trichoderma oligosporum forms reddish brown stromata with a downy surface, hyaline conidia and gliocladium-like conidiophores, and is closely related to but distinct from T. crystalligenum in the Psychrophila clade. Trichoderma sinoluteum, as a member of the Polysporum clade, is characterized by pale yellow stromata, white pustulate conidiomata, pachybasium-like conidiophores, and hyaline conidia. Differences between the new species and their close relatives are discussed.

Phylogeny of the clinically relevant species of the emerging fungus Trichoderma and their antifungal susceptibilities

A set of 73 isolates of the emerging fungus Trichoderma isolated from human and animal clinical specimens were characterized morphologically and molecularly using a multilocus sequence analysis that included the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA and fragments of the translation elongation factor 1 alpha (Tef1), endochitinase CHI18-5 (Chi18-5), and actin 1 (Act1) genes. The most frequent species was Trichoderma longibrachiatum (26%), followed by Trichoderma citrinoviride (18%), the Hypocrea lixii/Trichoderma harzianum species complex (15%), the newly described species Trichoderma bissettii (12%), and Trichoderma orientale (11%). The most common anatomical sites of isolation in human clinical specimens were the respiratory tract (40%), followed by deep tissue (30%) and superficial tissues (26%), while all the animal-associated isolates were obtained from superficial tissue samples. Susceptibilities of the isolates to eight antifungal drugs in vitro showed mostly high MICs, except for voriconazole and the echinocandins.

Two new antibiotic pyridones produced by a marine fungus, Trichoderma sp. strain MF106

Two unusual pyridones, trichodin A (1) and trichodin B (2), together with the known compound, pyridoxatin (3), were extracted from mycelia and culture broth of the marine fungus, Trichoderma sp. strain MF106 isolated from the Greenland Seas. The structures of the new compounds were characterized as an intramolecular cyclization of a pyridine basic backbone with a phenyl group. The structure and relative configuration of the new compounds were established by spectroscopic means. The new compound 1 and the known compound 3 showed antibiotic activities against the clinically relevant microorganism, Staphylococcus epidermidis, with IC₅₀ values of 24 μM and 4 μM, respectively.

Isolated sinusitis sphenoidalis caused by Trichoderma longibrachiatum in an immunocompetent patient with headache

We present a case of isolated sinusitis sphenoidalis caused by Trichoderma longibrachiatum, an emerging causal agent of fungal infections with an often fatal outcome. A Trichoderma strain was isolated from secretion obtained from the sinus sphenoidalis of a rhinosinusitis patient and identified by sequence analysis of two loci as Trichoderma longibrachiatum from the Longibrachiatum Clade of the genus Trichoderma. T. longibrachiatum can trigger a fatal pathomechanism in immunodeficient patients, but only rarely causes disease in healthy people. The case presented is unique because the patient was not immunocompromised.

Blue pigment in Hypocrea caerulescens sp. nov. and two additional new species in sect. Trichoderma

Three new species of Hypocrea/Trichoderma sect. Trichoderma (Hypocreaceae, Hypocreales, Ascomycota, Fungi) are described from recent collections in southern Europe and the Canary Islands. They have been characterized by morphological and molecular methods, including microscopic examination of the teleomorph in thin sections, the anamorph, growth rate experiments and phylogenetic analyses based on a part of the translation elongation factor 1-alpha encoding gene (tef1) containing the two last introns and a part of the rpb2 gene, encoding the second largest RNA polymerase subunit. Analyses involving tef1 did not unequivocally resolve the sister clade relationship of Hypocrea caerulescens relative to the Koningii and Viride clades, while analyses based on rpb2 clearly suggest a close relationship with the former, although the phenotype of H. caerulescens is similar to H. viridescens, particularly by its warted conidia and a coconut-like odor in CMD culture. Hypocrea hispanica and T. samuelsii however are clearly related to the Viride clade by both phylogenetic markers, despite their morphological similarity to H. koningii and its relatives. An apparently specific blue pigment is formed in CMD cultures by Hypocrea caerulescens but could not be obtained by extraction with organic solvents.

Molecular phylogeny and species delimitation in the section Longibrachiatum of Trichoderma

The phylogenetically most derived group of the genus Trichoderma - section Longibrachiatum, includes some of the most intensively studied species, such as the industrial cellulase producer T. reesei (teleomorph Hypocrea jecorina), or the facultative opportunistic human pathogens T. longibrachiatum and H. orientalis. At the same time, the phylogeny of this clade is only poorly understood. Here we used a collection of 112 strains representing all currently recognized species and isolates that were tentatively identified as members of the group, to analyze species diversity and molecular evolution. Bayesian phylogenetic analyses based on several unlinked loci in individual and concatenated datasets confirmed 13 previously described species and 3 previously recognized phylogenetic species all of which were not yet described formally. When the genealogical concordance criterion, the K/θ method and comparison of frequencies of pairwise nucleotide differences were applied to the data sample, 10 additional new phylogenetic species were recognized, seven of which consisted only of a single lineage. Our analysis thus identifies 26 putative species in section Longibrachiatum, what doubles the currently estimated taxonomic diversity of the group, and illustrates the power of combining genealogical concordance and population genetic analysis for dissecting species in a recently diverged group of fungal species.

The Longibrachiatum Clade of Trichoderma: a revision with new species

The Longibrachiatum Clade of Trichoderma is revised. Eight new species are described (T. aethiopicum, T. capillare, T. flagellatum, T. gillesii, T. gracile, T. pinnatum, T. saturnisporopsis, T. solani). The twenty-one species known to belong to the Longibrachiatum Clade are included in a synoptic key. Trichoderma parareesei and T. effusum are redescribed based on new collections or additional observations. Hypocrea teleomorphs are reported for T. gillesii and T. pinnatum. Previously described species are annotated.

Trichoderma: the genomics of opportunistic success

Trichoderma is a genus of common filamentous fungi that display a remarkable range of lifestyles and interactions with other fungi, animals and plants. Because of their ability to antagonize plant-pathogenic fungi and to stimulate plant growth and defence responses, some Trichoderma strains are used for biological control of plant diseases. In this Review, we discuss recent advances in molecular ecology and genomics which indicate that the interactions of Trichoderma spp. with animals and plants may have evolved as a result of saprotrophy on fungal biomass (mycotrophy) and various forms of parasitism on other fungi (mycoparasitism), combined with broad environmental opportunism.

Marine isolates of Trichoderma spp. as potential halotolerant agents of biological control for arid-zone agriculture

The scarcity of fresh water in the Mediterranean region necessitates the search for halotolerant agents of biological control of plant diseases that can be applied in arid-zone agriculture irrigated with saline water. Among 29 Trichoderma strains previously isolated from Mediterranean Psammocinia sp. sponges, the greatest number of isolates belong to the Trichoderma longibrachiatum-Hypocrea orientalis species pair (9), H. atroviridis/T. atroviride (9), and T. harzianum species complex (7), all of which are known for high mycoparasitic potential. In addition, one isolate of T. asperelloides and two putative new species, Trichoderma sp. O.Y. 14707 and O.Y. 2407, from Longibrachiatum and Strictipilosa clades, respectively, have been identified. In vitro salinity assays showed that the ability to tolerate increasing osmotic pressure (halotolerance) is a strain- or clade-specific property rather than a feature of a species. Only a few isolates were found to be sensitive to increased salinity, while others either were halotolerant or even demonstrated improved growth in increasingly saline conditions. In vitro antibiosis assays revealed strong antagonistic activity toward phytopathogens due to the production of both soluble and volatile metabolites. Two marine-derived Trichoderma isolates, identified as T. atroviride and T. asperelloides, respectively, effectively reduced Rhizoctonia solani damping-off disease on beans and also induced defense responses in cucumber seedlings against Pseudomonas syringae pv. lachrimans. This is the first inclusive evaluation of marine fungi as potential biocontrol agents.

Species diversity of Trichoderma in Poland

In the present study, we reinvestigate the diversity of Trichoderma in Poland utilizing a combination of morphological and molecular/phylogenetic methods. A total of 170 isolates were collected from six different substrata at 49 sites in Poland. These were divided among 14 taxa as follows: 110 of 170 Trichoderma isolates were identified to the species level by the analysis of their ITS1, ITS2 rDNA sequences as: T. harzianum (43 isolates), T. aggressivum (35), T. citrinoviride (11), T. hamatum (9), T. virens (6), T. longibrachiatum (4), T. polysporum (1), and T. tomentosum (1); 60 isolates belonging to the Viride clade were identified based on a fragment of the translation-elongation factor 1-alpha (tef1) gene as: T. atroviride (20 isolates), T. gamsii (2), T. koningii (17), T. viridescens (13), T. viride (7), and T. koningiopsis (1). Identifications were made using the BLAST interface in TrichOKEY and TrichoBLAST ( http://www.isth.info ). The most diverse substrata were soil (nine species per 22 isolates) and decaying wood (nine species per 75 isolates). The most abundant species (25%) isolated from all substrata was T. harzianum.

M13-microsatellite PCR and rDNA sequence markers for identification of Trichoderma (Hypocreaceae) species in Saudi Arabian soil

Seven fungal isolates were identified as pan-global Hypocrea/Trichoderma species, from section Trichoderma, on the basis of their morphology. These species were H. lixii/T. harzianum and H. orientalis/T. longibrachiatum. PCR-based markers with primer M13 (core sequence of phage M13) and internal-transcribed spacer sequences of ribosomal DNA were used to confirm the identity of the two Trichoderma species. Sequence identification was performed using the TrichOKEY version 2.0 barcode program and the multilocus similarity search database TrichoBLAST. Sequences from the ribosomal DNA internal-transcribed spacer regions showed limited variation among the Trichoderma species. This analysis divided the isolates into two main groups. Grouping the isolates based on cluster analysis of their DNA profiles matched the grouping based on morphological taxonomy. Molecular data obtained from analyses of gene sequences are essential to distinguish phonetically cryptic species in this group and to establish phylogenetic relationships.

Biology and biotechnology of Trichoderma

Fungi of the genus Trichoderma are soilborne, green-spored ascomycetes that can be found all over the world. They have been studied with respect to various characteristics and applications and are known as successful colonizers of their habitats, efficiently fighting their competitors. Once established, they launch their potent degradative machinery for decomposition of the often heterogeneous substrate at hand. Therefore, distribution and phylogeny, defense mechanisms, beneficial as well as deleterious interaction with hosts, enzyme production and secretion, sexual development, and response to environmental conditions such as nutrients and light have been studied in great detail with many species of this genus, thus rendering Trichoderma one of the best studied fungi with the genome of three species currently available. Efficient biocontrol strains of the genus are being developed as promising biological fungicides, and their weaponry for this function also includes secondary metabolites with potential applications as novel antibiotics. The cellulases produced by Trichoderma reesei, the biotechnological workhorse of the genus, are important industrial products, especially with respect to production of second generation biofuels from cellulosic waste. Genetic engineering not only led to significant improvements in industrial processes but also to intriguing insights into the biology of these fungi and is now complemented by the availability of a sexual cycle in T. reesei/Hypocrea jecorina, which significantly facilitates both industrial and basic research. This review aims to give a broad overview on the qualities and versatility of the best studied Trichoderma species and to highlight intriguing findings as well as promising applications.

Sexual development in the industrial workhorse Trichoderma reesei

Filamentous fungi are indispensable biotechnological tools for the production of organic chemicals, enzymes, and antibiotics. Most of the strains used for industrial applications have been--and still are--screened and improved by classical mutagenesis. Sexual crossing approaches would yield considerable advantages for research and industrial strain improvement, but interestingly, industrially applied filamentous fungal species have so far been considered to be largely asexual. This is also true for the ascomycete Trichoderma reesei (anamorph of Hypocrea jecorina), which is used for production of cellulolytic and hemicellulolytic enzymes. In this study, we report that T. reesei QM6a has a MAT1-2 mating type locus, and the identification of its respective mating type counterpart, MAT1-1, in natural isolates of H. jecorina, thus proving that this is a heterothallic species. After being considered asexual since its discovery more than 50 years ago, we were now able to induce sexual reproduction of T. reesei QM6a and obtained fertilized stromata and mature ascospores. This sexual crossing approach therefore opens up perspectives for biotechnologically important fungi. Our findings provide a tool for fast and efficient industrial strain improvement in T. reesei, thus boosting research toward economically feasible biofuel production. In addition, knowledge of MAT-loci and sexual crossing techniques will facilitate research with other Trichoderma spp. relevant for agriculture and human health.

Fatal Trichoderma harzianum infection in a leukemic pediatric patient

We report the repeated isolation for Trichoderma.harzianum, a rare opportunistic pathogen from three sets of each of the following clinical samples; blood serum, skin lesions, sputum and throat of a pediatric ALL patient with neutropenia. The definition of invasive fungal infection requires evidence of the presence of fungal elements in tissue samples, in addition to the isolation of suspected etiologic agent in culture. However, invasive procedures are not always applicable due to several factors, as for example in our case, the poor general status of the individual patient or thrombocytopenia. The present paper also emphasizes the problems encountered in obtaining appropriate samples and diagnosing invasive fungal disease in immunocompromised patient populations, including those with hematological malignancy. Three cases involving T. harzianum, including this one, have been described thus far in the literature. All were fatal and the fungus was resistant to antifungal therapy. A critical review of the other two cases of Trichoderma infections in humans is provided.

European species of Hypocrea Part I. The green-spored species

At present 75 species of Hypocrea have been identified in temperate Europe. Nineteen green-spored species and their Trichoderma asexual states are here described in detail. Extensive searches for Hypocrea teleomorphs in 14 European countries, with emphasis on Central Europe, yielded more than 620 specimens within five years. The morphology of fresh and dry stromata was studied. In addition, available types of species described from Europe were examined. Cultures were prepared from ascospores and used to study the morphology of cultures and anamorphs, to determine growth rates, and to extract DNA that was used for amplification and sequencing of three genetic markers. ITS was used for identification, while RNA polymerase II subunit b (rpb2) and translation elongation factor 1 alpha (tef1) were analyzed for phylogenetic reconstruction of the genus.SEVERAL UNEXPECTED FINDINGS RESULTED FROM THIS PROJECT: 1) The previous view that only a small number of Trichoderma species form a teleomorph is erroneous. 2) All expectations concerning the number of species in Europe are by far exceeded. Seventy-five species of Hypocrea, two species of Protocrea, and Arachnocrea stipata, are herein identified in temperate Europe, based on the ITS identification routine using fresh material, on species described earlier without molecular data and on species recently described but not collected during this project. 3) Current data suggest that the biodiversity of Hypocrea / Trichoderma above soil exceeds the number of species isolated from soil. 4) The number of Trichoderma species forming hyaline conidia has been considered a small fraction. In Europe, 26 species of those forming teleomorphs produce hyaline conidia, while 42 green-conidial species are known. Three of the detected Hypocrea species do not form an anamorph in culture, while the anamorph is unknown in four species, because they have never been cultured.This work is a preliminary account of Hypocrea and their Trichoderma anamorphs in Europe. Of the hyaline-spored species, H. minutispora is by far the most common species in Europe, while of the green-spored species this is H. strictipilosa.General ecology of Hypocrea is discussed. Specific associations, either with host fungi or trees have been found, but the majority of species seems to be necrotrophic on diverse fungi on wood and bark.The taxonomy of the genus will be treated in two parts. In this first part 19 species of Hypocrea with green ascospores, including six new teleomorph and five new anamorph species, are described in detail. All green-spored species belong to previously recognised clades, except H. spinulosa, which forms the new Spinulosa Clade with two additional new species, and H. fomiticola, which belongs to the Semiorbis Clade and forms effuse to large subpulvinate stromata on Fomes fomentarius, a trait new for species with green ascospores. Anamorph names are established prospectively in order to provide a basis for possible policy alterations towards their use for holomorphs.

Fungal genus Hypocrea/Trichoderma: from barcodes to biodiversity

Hypocrea/Trichoderma is a genus of soil-borne or wood-decaying fungi containing members important to mankind as producers of industrial enzymes and biocontrol agents against plant pathogens, but also as opportunistic pathogens of immunocompromised humans and animals, while others can cause damage to cultivated mushroom. With the recent advent of a reliable, BarCode-aided identification system for all known taxa of Trichoderma and Hypocrea, it became now possible to study some of the biological fundamentals of the diversity in this fungal genus in more detail. In this article, we will therefore review recent progress in (1) the understanding of the geographic distribution of individual taxa; (2) mechanisms of speciation leading to development of mushroom diseases and facultative human mycoses; and (3) the possible correlation of specific traits of secondary metabolism and molecular phylogeny.