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Parasitism is an important lifestyle in the Trichoderma genus but has not been studied in a genus-wide way toward Pythium and Globisporangium hosts. Our approach screened a genus-wide set of 30 Trichoderma species in dual culture assays with two soil-borne Pythium and three Globisporangium plant-parasitic species and used exo-proteomic analyses, with the aim to correlate Trichoderma antagonism with potential strategies for attacking Pythium and Globisporangium. The Trichoderma spp. showed a wide range of antagonism from strong to weak, but the same Trichoderma strain showed similar levels toward all the Pythium and Globisporangium species. The Trichoderma enzymes from strong (Trichoderma asperellum, Trichoderma atroviride, and Trichoderma virens), moderate (Trichoderma cf. guizhouense and Trichoderma reesei), and weak (Trichoderma parepimyces) antagonists were induced by the autoclaved mycelia of one of the screened Pythium species, Pythium myriotylum. The variable proportions of putative cellulases, proteases, and redox enzymes suggested diverse as well as shared strategies amongst the antagonists. There was a partial positive correlation between antagonism from microscopy and the cellulase activity induced by autoclaved P. myriotylum mycelia in different Trichoderma species. The deletion of the cellulase transcriptional activator XYR1 in T. reesei led to lower antagonism toward Pythium and Globisporangium. The antagonism of Pythium and Globisporangium appears to be a generic property of Trichoderma as most of the Trichoderma species were at least moderately antagonistic. While a role for cellulases in the antagonism was uncovered, cellulases did not appear to make a major contribution to T. reesei antagonism, and other factors are also likely contributing.IMPORTANCETrichoderma is an important genus widely distributed in nature with broad ecological impacts and applications in the biocontrol of plant diseases. The Pythium and Globisporangium genera of fungus-like water molds include many important soil-borne plant pathogens that cause various diseases. Most of the Trichoderma species showed at least a moderate ability to compete with or antagonize the Pythium and Globisporangium hosts, and microscopy showed examples of parasitism (a slow type of killing) and predation (a fast type of killing). Hydrolytic enzymes such as cellulases and proteases produced by Trichoderma likely contribute to the antagonism. A mutant deficient in cellulase activity had reduced antagonism. Interestingly, Pythium and Globisporangium species contain cellulose in their cell walls (unlike true fungi such as Trichoderma), and the cellulolytic ability of Trichoderma appears beneficial for antagonism of water molds.
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The regulation of plant biomass degradation by fungi is critical to the carbon cycle, and applications in bioproducts and biocontrol. Trichoderma harzianum is an important plant biomass degrader, enzyme producer, and biocontrol agent, but few putative major transcriptional regulators have been deleted in this species. The T. harzianum ortholog of the transcriptional activator XYR1/XlnR/XLR-1 was deleted, and the mutant strains were analyzed through growth profiling, enzymatic activities, and transcriptomics on cellulose. From plate cultures, the Δxyr1 mutant had reduced growth on D-xylose, xylan, and cellulose, and from shake-flask cultures with cellulose, the Δxyr1 mutant had ~90% lower ß-glucosidase activity, and no detectable ß-xylosidase or cellulase activity. The comparison of the transcriptomes from 18 h shake-flask cultures on D-fructose, without a carbon source, and cellulose, showed major effects of XYR1 deletion whereby the Δxyr1 mutant on cellulose was transcriptionally most similar to the cultures without a carbon source. The cellulose induced 43 plant biomass-degrading CAZymes including xylanases as well as cellulases, and most of these had massively lower expression in the Δxyr1 mutant. The expression of a subset of carbon catabolic enzymes, other transcription factors, and sugar transporters was also lower in the Δxyr1 mutant on cellulose. In summary, T. harzianum XYR1 is the master regulator of cellulases and xylanases, as well as regulating carbon catabolic enzymes.
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Celulasas , Hypocreales , Biomasa , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Factores de Transcripción/metabolismo , Perfilación de la Expresión Génica , Hypocreales/metabolismo , Celulosa , CarbonoRESUMEN
Establishing mutualistic relationships between plants and fungi is crucial for overcoming nutrient deficiencies in plants. This review highlights the intricate nutrient sensing and uptake mechanisms used by plants in response to phosphate and nitrogen starvation, as well as their interactions with plant immunity. The coordination of transport systems in both host plants and fungal partners ensures efficient nutrient uptake and assimilation, contributing to the long-term maintenance of these mutualistic associations. It is also essential to understand the distinct responses of fungal partners to external nutrient levels and forms, as they significantly impact the outcomes of symbiotic interactions. Our review also highlights the importance of evolutionarily younger and newly discovered root-fungus associations, such as endophytic associations, which offer potential benefits for improving plant nutrition. Mechanistic insights into the complex dynamics of phosphorus and nitrogen sensing within diverse root-fungus associations can facilitate the identification of molecular targets for engineering symbiotic systems and developing plant phenotypes with enhanced nutrient use efficiency. Ultimately, this knowledge can inform tailored fertilizer management practices to optimize plant nutrition.
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Nitrógeno , Fósforo , Simbiosis , Plantas/microbiología , Hongos/fisiología , Raíces de Plantas/microbiologíaRESUMEN
Research into plastic-degrading bacteria and fungi is important for understanding how microorganisms can be used to address the problem of plastic pollution and for developing new approaches to sustainable waste management and bioplastic production. In the present study, we isolated 55 bacterial and 184 fungal strains degrading polycaprolactone (PCL) in plastic waste samples from Dafeng coastal salt marshes, Jiangsu, China. Of these, Jonesia and Streptomyces bacteria also showed potential to degrade other types of petroleum-based polymers. The metabarcoding results proved the existence of plastisphere as a distinct ecological niche regardless of the plastic types where 27 bacterial and 29 fungal amplicon sequence variants (ASVs) were found to be significantly (p < 0.05) enriched, including some belonging to Alternaria (Ascomycota, Fungi) and Pseudomonas (Gammaproteobacteria, Bacteria) that were also mined out by the method of cultivation. Further assembly analyses demonstrated the importance of deterministic processes especially the environmental filtering effect of carbon content and pH on bacteria as well as the carbon and cation content on fungi in shaping the plastisphere communities in this ecosystem. Thus, the unique microbiome of the plastisphere in the terrestrial-marine ecotone is enriched with microorganisms that are potentially capable of utilizing petroleum-based polymers, making it a valuable resource for screening plastic biodegraders.
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Ascomicetos , Microbiota , Petróleo , Polímeros , Plásticos , Bacterias/genética , Biodegradación AmbientalRESUMEN
Increasing nitrogen (N) deposition often tends to negatively impact the functions of belowground ectomycorrhizal networks, although the exact molecular mechanisms underlying this trait are still unclear. Here, we assess how the root-associated fungus Clitopilus hobsonii establishes an ectomycorrhiza-like association with its host tree Populus tomentosa and how this interaction is favored by organic N over mineral N. The establishment of a functional symbiosis in the presence of organic N promotes plant growth and the transfer of 15N from the fungus to above ground plant tissues. Genomic traits and in planta transcriptional signatures suggest that C. hobsonii may have a dual lifestyle with saprotrophic and mutualistic traits. For example, several genes involved in the digestion of cellulose and hemicellulose are highly expressed during the interaction, whereas the expression of multiple copies of pectin-digesting genes is tightly controlled. Conversely, the nutritional mutualism is dampened in the presence of ammonium (NH4+) or nitrate (NO3-). Increasing levels of NH4+ led to a higher expression of pectin-digesting genes and a continuous increase in hydrogen peroxide production in roots, whereas the presence of NO3- resulted in toxin production. In summary, our results suggest that C. hobsonii is a facultative ectomycorrhizal fungus. Access to various forms of N acts as an on/off switch for mutualism caused by large-scale fungal physiological remodeling. Furthermore, the abundance of pectin-degrading enzymes with distinct expression patterns during functional divergence after exposure to NH4+ or organic N is likely to be central to the transition from parasitism to mutualism.
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Compuestos de Amonio , Micorrizas , Micorrizas/fisiología , Nitrógeno/metabolismo , Simbiosis , Nitratos , Compuestos de Amonio/metabolismo , Raíces de Plantas/metabolismoRESUMEN
The Pythium (Peronosporales, Oomycota) genus includes devastating plant pathogens that cause widespread diseases and severe crop losses. Here, we have uncovered a far greater arsenal of virulence factor-related genes in the necrotrophic Pythium myriotylum than in other Pythium plant pathogens. The genome of a plant-virulent P. myriotylum strain (~70 Mb and 19,878 genes) isolated from a diseased rhizome of ginger (Zingiber officinale) encodes the largest repertoire of putative effectors, proteases, and plant cell wall-degrading enzymes (PCWDEs) among the studied species. P. myriotylum has twice as many predicted secreted proteins than any other Pythium plant pathogen. Arrays of tandem duplications appear to be a key factor of the enrichment of the virulence factor-related genes in P. myriotylum. The transcriptomic analysis performed on two P. myriotylum isolates infecting ginger leaves showed that proteases were a major part of the upregulated genes along with PCWDEs, Nep1-like proteins (NLPs), and elicitin-like proteins. A subset of P. myriotylum NLPs were analyzed and found to have necrosis-inducing ability from agroinfiltration of tobacco (Nicotiana benthamiana) leaves. One of the heterologously produced infection-upregulated putative cutinases found in a tandem array showed esterase activity with preferences for longer-chain-length substrates and neutral to alkaline pH levels. Our results allow the development of science-based targets for the management of P. myriotylum-caused disease, as insights from the genome and transcriptome show that gene expansion of virulence factor-related genes play a bigger role in the plant parasitism of Pythium spp. than previously thought. IMPORTANCE Pythium species are oomycetes, an evolutionarily distinct group of filamentous fungus-like stramenopiles. The Pythium genus includes several pathogens of important crop species, e.g., the spice ginger. Analysis of our genome from the plant pathogen Pythium myriotylum uncovered a far larger arsenal of virulence factor-related genes than found in other Pythium plant pathogens, and these genes contribute to the infection of the plant host. The increase in the number of virulence factor-related genes appears to have occurred through the mechanism of tandem gene duplication events. Genes from particular virulence factor-related categories that were increased in number and switched on during infection of ginger leaves had their activities tested. These genes have toxic activities toward plant cells or activities to hydrolyze polymeric components of the plant. The research suggests targets to better manage diseases caused by P. myriotylum and prompts renewed attention to the genomics of Pythium plant pathogens.
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Pythium , Zingiber officinale , Péptido Hidrolasas , Enfermedades de las Plantas , Plantas , Pythium/genética , Virulencia/genética , Factores de Virulencia/genéticaRESUMEN
The filamentous mycoparasitic fungus Trichoderma asperelloides (Hypocreales, Ascomycota, Dikarya) strain T 203 was isolated from soil in Israel by the Ilan Chet group in the 1980s. As it has been the subject of laboratory, greenhouse, and field experiments and has been incorporated into commercial agricultural preparations, its genome has been sequenced and analyzed.
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Biological waste degradation is the main driving factor for landfill emissions. In a 2-year laboratory experiment simulating different landfill in-situ aeration scenarios, the microbial degradation of solid waste under different oxygen conditions (treatments) was investigated. Nine landfill simulation reactors were operated in triplicates under three distinct treatments. Three were kept anaerobic, three were aerated for 706 days after an initial anaerobic phase and three were aerated for 244 days in between two anaerobic phases. In total, 36 solid and 36 leachate samples were taken. Biolog® EcoPlates™ were used to assess the functional diversity of the microbial community. It was possible to directly relate the functional diversity to the biodegradability of MSW (municipal solid waste), measured as RI4 (respiration index after 4 days). The differences between the treatments in RI4 as well as in carbon and polymer degradation potential were small. Initially, a RI4 of about 6.5 to 8 mg O2 kg-1 DW was reduced to less than 1 mg O2 kg-1 DW within 114 days of treatment. After the termination of aeration, an increase 3 mg O2 kg-1 DW was observed. By calculating the integral of the Gompertz equation based on spline interpolation of the Biolog® EcoPlates™ results after 96 h two substrate groups mainly contributing to the biodegradability were identified: carbohydrates and polymers. The microbial activity of the respective microbial consortium could thus be related to the biodegradability with a multilinear regression model.
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Eliminación de Residuos , Contaminantes Químicos del Agua , Biodegradación Ambiental , Reactores Biológicos , Carbohidratos , Polímeros , Eliminación de Residuos/métodos , Residuos Sólidos , Instalaciones de Eliminación de Residuos , Contaminantes Químicos del Agua/análisisRESUMEN
Comparative and pan-genomic analyses of the endophytic fungus Pezicula neosporulosa (Helotiales, Ascomycota) from needles of the relict fir, Abies beshanzuensis, showed expansions of carbohydrate metabolism and secondary metabolite biosynthetic genes characteristic for unrelated plant-beneficial helotialean, such as dark septate endophytes and ericoid mycorrhizal fungi. The current species within the relatively young Pliocene genus Pezicula are predominantly saprotrophic, while P. neosporulosa lacks such features. To understand the genomic background of this putatively convergent evolution, we performed population analyses of 77 P. neosporulosa isolates. This revealed a mosaic structure of a dozen non-recombining and highly genetically polymorphic subpopulations with a unique mating system structure. We found that one idiomorph of a probably duplicated mat1-2 gene was found in putatively heterothallic isolates, while the other co-occurred with mat1-1 locus suggesting homothallic reproduction for these strains. Moreover, 24 and 81 genes implicated in plant cell-wall degradation and secondary metabolite biosynthesis, respectively, showed signatures of the balancing selection. These findings highlight the evolutionary pattern of the two gene families for allowing the fungus a rapid adaptation towards endophytism and facilitating diverse symbiotic interactions.
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Genes del Tipo Sexual de los Hongos , Genómica , Aclimatación , Endófitos , ReproducciónRESUMEN
Biological control is a promising approach to suppress diseases caused by Pythium spp. such as Pythium soft rot of ginger caused by P. myriotylum. Unusually for a single genus, it also includes species that can antagonize Pythium plant pathogens, such as Pythium oligandrum. We investigated if a new isolate of P. oligandrum could antagonize P. myriotylum, what changes occurred in gene expression when P. oligandrum (antagonist) and P. myriotylum (host) interacted, and whether P. oligandrum could control soft-rot of ginger caused by P. myriotylum. An isolate of P. oligandrum, GAQ1, recovered from soil could antagonize P. myriotylum in a plate-based confrontation assay whereby P. myriotylum became non-viable. The loss of viability of P. myriotylum coupled with how P. oligandrum hyphae could coil around and penetrate the hyphae of P. myriotylum, indicated a predatory interaction. We investigated the transcriptional responses of P. myriotylum and P. oligandrum using dual-RNAseq at a stage in the confrontation where similar levels of total transcripts were measured from each species. As part of the transcriptional response of P. myriotylum to the presence of P. oligandrum, genes including a subset of putative Kazal-type protease inhibitors were strongly upregulated along with cellulases, elicitin-like proteins and genes involved in the repair of DNA double-strand breaks. In P. oligandrum, proteases, cellulases, and peroxidases featured prominently in the upregulated genes. The upregulation along with constitutive expression of P. oligandrum proteases appeared to be responded to by the upregulation of putative protease inhibitors from P. myriotylum, suggesting a P. myriotylum defensive strategy. Notwithstanding this P. myriotylum defensive strategy, P. oligandrum had a strong disease control effect on soft-rot of ginger caused by P. myriotylum. The newly isolated strain of P. oligandrum is a promising biocontrol agent for suppressing the soft-rot of ginger. The dual-RNAseq approach highlights responses of P. myriotylum that suggests features of a defensive strategy, and are perhaps another factor that may contribute to the variable success and durability of biological attempts to control diseases caused by Pythium spp.
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Higher fungi can rapidly produce large numbers of spores suitable for aerial dispersal. The efficiency of the dispersal and spore resilience to abiotic stresses correlate with their hydrophobicity provided by the unique amphiphilic and superior surface-active proteins-hydrophobins (HFBs)-that self-assemble at hydrophobic/hydrophilic interfaces and thus modulate surface properties. Using the HFB-enriched mold Trichoderma (Hypocreales, Ascomycota) and the HFB-free yeast Pichia pastoris (Saccharomycetales, Ascomycota), we revealed that the rapid release of HFBs by aerial hyphae shortly prior to conidiation is associated with their intracellular accumulation in vacuoles and/or lipid-enriched organelles. The occasional internalization of the latter organelles in vacuoles can provide the hydrophobic/hydrophilic interface for the assembly of HFB layers and thus result in the formation of HFB-enriched vesicles and vacuolar multicisternal structures (VMSs) putatively lined up by HFBs. These HFB-enriched vesicles and VMSs can become fused in large tonoplast-like organelles or move to the periplasm for secretion. The tonoplast-like structures can contribute to the maintenance of turgor pressure in aerial hyphae supporting the erection of sporogenic structures (e.g., conidiophores) and provide intracellular force to squeeze out HFB-enriched vesicles and VMSs from the periplasm through the cell wall. We also show that the secretion of HFBs occurs prior to the conidiation and reveal that the even spore coating of HFBs deposited in the extracellular matrix requires microscopic water droplets that can be either guttated by the hyphae or obtained from the environment. Furthermore, we demonstrate that at least one HFB, HFB4 in T. guizhouense, is produced and secreted by wetted spores. We show that this protein possibly controls spore dormancy and contributes to the water sensing mechanism required for the detection of germination conditions. Thus, intracellular HFBs have a range of pleiotropic functions in aerial hyphae and spores and are essential for fungal development and fitness.
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Pared Celular/genética , Proteínas Fúngicas/genética , Esporas Fúngicas/genética , Trichoderma/genética , Ascomicetos/genética , Ascomicetos/crecimiento & desarrollo , Interacciones Hidrofóbicas e Hidrofílicas , Hifa/genética , Hifa/crecimiento & desarrollo , Hypocreales/genética , Hypocreales/crecimiento & desarrollo , Esporas Fúngicas/crecimiento & desarrollo , Trichoderma/crecimiento & desarrolloRESUMEN
Understanding how organisms adapt to extreme living conditions is central to evolutionary biology. Dark septate endophytes (DSEs) constitute an important component of the root mycobiome and they are often able to alleviate host abiotic stresses. Here, we investigated the molecular mechanisms underlying the beneficial association between the DSE Laburnicola rhizohalophila and its host, the native halophyte Suaeda salsa, using population genomics. Based on genome-wide Fst (pairwise fixation index) and Vst analyses, which compared the variance in allele frequencies of single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs), respectively, we found a high level of genetic differentiation between two populations. CNV patterns revealed population-specific expansions and contractions. Interestingly, we identified a ~20 kbp genomic island of high divergence with a strong sign of positive selection. This region contains a melanin-biosynthetic polyketide synthase gene cluster linked to six additional genes likely involved in biosynthesis, membrane trafficking, regulation, and localization of melanin. Differences in growth yield and melanin biosynthesis between the two populations grown under 2% NaCl stress suggested that this genomic island contributes to the observed differences in melanin accumulation. Our findings provide a better understanding of the genetic and evolutionary mechanisms underlying the adaptation to saline conditions of the L. rhizohalophila-S. salsa symbiosis.
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Ascomicetos , Chenopodiaceae , Islas Genómicas , Plantas Tolerantes a la Sal/microbiología , Ascomicetos/genética , Chenopodiaceae/microbiología , Endófitos/genética , Melaninas , PigmentaciónRESUMEN
The production of biofuels from plant biomass is dependent on the availability of enzymes that can hydrolyze the plant cell wall polysaccharides to their monosaccharides. These enzyme mixtures are formed by microorganisms but their native compositions and properties are often not ideal for application. Genetic engineering of these microorganisms is therefore necessary, in which introduction of DNA is an essential precondition. The filamentous fungus Trichoderma reesei-the main producer of plant-cell-wall-degrading enzymes for biofuels and other industries-has been subjected to intensive genetic engineering toward this goal and has become one of the iconic examples of the successful genetic improvement of fungi. However, the genetic manipulation of other enzyme-producing Trichoderma species is frequently less efficient and, therefore, rarely managed. In this chapter, we therefore describe the two potent methods of Trichoderma transformation mediated by either (a) polyethylene glycol (PEG) or (b) Agrobacterium. The methods are optimized for T. reesei but can also be applied for such transformation-resilient species as T. harzianum and T. guizhouense, which are putative upcoming alternatives for T. reesei in this field. The protocols are simple, do not require extensive training or special equipment, and can be further adjusted for T. reesei mutants with particular properties.
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Ingeniería Genética/métodos , Transformación Genética/genética , Trichoderma/genética , Biocombustibles , Biomasa , Celulasa/genética , Celulosa/genética , Hidrólisis , Monosacáridos/genética , Plantas/química , Plantas/metabolismo , Trichoderma/metabolismoRESUMEN
In this review, we argue that there is much to be learned by transferring knowledge from research on lignocellulose degradation to that on plastic. Plastic waste accumulates in the environment to hazardous levels, because it is inherently recalcitrant to biological degradation. Plants evolved lignocellulose to be resistant to degradation, but with time, fungi became capable of utilising it for their nutrition. Examples of how fungal strategies to degrade lignocellulose could be insightful for plastic degradation include how fungi overcome the hydrophobicity of lignin (e.g. production of hydrophobins) and crystallinity of cellulose (e.g. oxidative approaches). In parallel, knowledge of the methods for understanding lignocellulose degradation could be insightful such as advanced microscopy, genomic and post-genomic approaches (e.g. gene expression analysis). The known limitations of biological lignocellulose degradation, such as the necessity for physiochemical pretreatments for biofuel production, can be predictive of potential restrictions of biological plastic degradation. Taking lessons from lignocellulose degradation for plastic degradation is also important for biosafety as engineered plastic-degrading fungi could also have increased plant biomass degrading capabilities. Even though plastics are significantly different from lignocellulose because they lack hydrolysable C-C or C-O bonds and therefore have higher recalcitrance, there are apparent similarities, e.g. both types of compounds are mixtures of hydrophobic polymers with amorphous and crystalline regions, and both require hydrolases and oxidoreductases for their degradation. Thus, many lessons could be learned from fungal lignocellulose degradation.
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Lignina , Plásticos , Celulosa , Hongos/genéticaRESUMEN
The identification and proper naming of microfungi, in particular plant, animal and human pathogens, remains challenging. Molecular identification is becoming the default approach for many fungal groups, and environmental metabarcoding is contributing an increasing amount of sequence data documenting fungal diversity on a global scale. This includes lineages represented only by sequence data. At present, these taxa cannot be formally described under the current nomenclature rules. By considering approaches used in bacterial taxonomy, we propose solutions for the nomenclature of taxa known only from sequences to facilitate consistent reporting and communication in the literature and public sequence repositories.
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Hongos/clasificación , Hongos/aislamiento & purificación , Animales , ADN de Hongos/genética , Microbiología Ambiental , Hongos/genética , Humanos , Micosis/microbiología , Enfermedades de las Plantas/microbiología , Análisis de Secuencia de ADN , Terminología como AsuntoRESUMEN
Several species of soil free-living saprotrophs can sometimes establish biotrophic symbiosis with plants, but the basic biology of this association remains largely unknown. Here, we investigate the symbiotic interaction between a common soil saprotroph, Clitopilus hobsonii (Agaricomycetes), and the American sweetgum (Liquidambar styraciflua). The colonized root cortical cells were found to contain numerous microsclerotia-like structures. Fungal colonization led to increased plant growth and facilitated potassium uptake, particularly under potassium limitation (0.05 mM K+ ). The expression of plant genes related to potassium uptake was not altered by the symbiosis, but colonized roots contained the transcripts of three fungal genes with homology to K+ transporters (ACU and HAK) and channel (SKC). Heterologously expressed ChACU and ChSKC restored the growth of a yeast K+ -uptake-defective mutant. Upregulation of ChACU transcript under low K+ conditions (0 and 0.05 mM K+ ) compared to control (5 mM K+ ) was demonstrated in planta and in vitro. Colonized plants displayed a larger accumulation of soluble sugars under 0.05 mM K+ than non-colonized plants. The present study suggests reciprocal benefits of this novel tree-fungus symbiosis under potassium limitation mainly through an exchange of additional carbon and potassium between both partners.
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Agaricales/fisiología , Liquidambar/fisiología , Raíces de Plantas/microbiología , Potasio/metabolismo , Simbiosis/fisiología , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulación Fúngica de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Liquidambar/crecimiento & desarrollo , Liquidambar/microbiología , Micorrizas/fisiología , Filogenia , Raíces de Plantas/metabolismo , Microbiología del Suelo , Azúcares/metabolismo , Levaduras/genéticaRESUMEN
In the course of investigations on peptaibol chemodiversity from marine-derived Trichoderma spp., five new 15-residue peptaibols named pentadecaibins I-V (1-5) were isolated from the solid culture of the strain Trichoderma sp. MMS1255 belonging to the T. harzianum species complex. Phylogenetic analyses allowed precise positioning of the strain close to T. lentiforme lineage inside the Harzianum clade. Peptaibol sequences were elucidated on the basis of their MS/MS fragmentation and extensive 2D NMR experiments. Amino acid configurations were determined by Marfey's analyses. The pentadecaibins are based on the sequences Ac-Aib1-Gly2-Ala3-Leu4-Aib/Iva5-Gln6-Aib/Iva7-Val/Leu8-Aib9-Ala10-Aib11-Aib12-Aib13-Gln14-Pheol15. Characteristic of the pentadecaibin sequences is the lack of the Aib-Pro motif commonly present in peptaibols produced by Trichoderma spp. Genome sequencing of Trichoderma sp. MMS1255 allowed the detection of a 15-module NRPS-encoding gene closely associated with pentadecaibin biosynthesis. Pentadecaibins were assessed for their potential antiproliferative and antimicrobial activities.
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Peptaiboles/química , Trichoderma/química , Secuencia de Aminoácidos , Organismos Acuáticos/química , Línea Celular Tumoral , Humanos , Pruebas de Sensibilidad Microbiana , Filogenia , Trichoderma/clasificaciónRESUMEN
The secretomes of filamentous fungi contain a diversity of small secreted cysteine-rich proteins (SSCPs) that have a variety of properties ranging from toxicity to surface activity. Some SSCPs are recognized by other organisms as indicators of fungal presence, but their function in fungi is not fully understood. We detected a new family of fungal surface-active SSCPs (saSSCPs), here named hyphosphere proteins (HFSs). An evolutionary analysis of the HFSs in Pezizomycotina revealed a unique pattern of eight single cysteine residues (C-CXXXC-C-C-C-C-C) and a long evolutionary history of multiple gene duplications and ancient interfungal lateral gene transfers, suggesting their functional significance for fungi with different lifestyles. Interestingly, recombinantly produced saSSCPs from three families (HFSs, hydrophobins and cerato-platanins) showed convergent surface-modulating activity on glass and on poly(ethylene-terephthalate), transforming their surfaces to a moderately hydrophilic state, which significantly favoured subsequent hyphal attachment. The addition of purified saSSCPs to the tomato rhizosphere had mixed effects on hyphal attachment to roots, while all tested saSSCPs had an adverse effect on plant growth in vitro. We propose that the exceptionally high diversity of saSSCPs in Trichoderma and other fungi evolved to efficiently condition various surfaces in the hyphosphere to a fungal-beneficial state.