RESUMO
Mycotoxin deoxynivalenol (DON) produced by the Fusarium graminearum complex is highly toxic to animal and human health. During DON synthesis, the endoplasmic reticulum (ER) of F. graminearum is intensively reorganized, from thin reticular structure to thickened spherical and crescent structure, which was referred to as "DON toxisome". However, the underlying mechanism of how the ER is reorganized into toxisome remains unknown. In this study, we discovered that overproduction of ER-localized DON biosynthetic enzyme Tri4 or Tri1, or intrinsic ER-resident membrane proteins FgHmr1 and FgCnx was sufficient to induce toxisome-shaped structure (TSS) formation under non-toxin-inducing conditions. Moreover, heterologous overexpression of Tri1 and Tri4 proteins in non-DON-producing fungi F. oxysporum f. sp. lycopersici and F. fujikuroi also led to TSS formation. In addition, we found that the high osmolarity glycerol (HOG), but not the unfolded protein response (UPR) signaling pathway was involved in the assembly of ER into TSS. By using toxisome as a biomarker, we screened and identified a novel chemical which exhibited high inhibitory activity against toxisome formation and DON biosynthesis, and inhibited Fusarium growth species-specifically. Taken together, this study demonstrated that the essence of ER remodeling into toxisome structure is a response to the overproduction of ER-localized DON biosynthetic enzymes, providing a novel pathway for management of mycotoxin contamination.
Assuntos
Fusarium , Micotoxinas , Tricotecenos , Humanos , Micotoxinas/metabolismo , Fusarium/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Retículo Endoplasmático/metabolismoRESUMO
Fusarium head blight (FHB), caused by Fusarium graminearum species complexes (FGSG), is an epidemic disease in wheat and poses a serious threat to wheat production and security worldwide. Profilins are a class of actin-binding proteins that participate in actin depolymerization. However, the roles of profilins in plant fungal pathogens remain largely unexplored. Here, we identified FgPfn, a homolog to profilins in F. graminearum, and the deletion of FgPfn resulted in severe defects in mycelial growth, conidia production, and pathogenicity, accompanied by marked disruptions in toxisomes formation and deoxynivalenol (DON) transport, while sexual development was aborted. Additionally, FgPfn interacted with Fgα1 and Fgß2, the significant components of microtubules. The organization of microtubules in the ΔFgPfn was strongly inhibited under the treatment of 0.4 µg/mL carbendazim, a well-known group of tubulin interferers, resulting in increased sensitivity to carbendazim. Moreover, FgPfn interacted with both myosin-5 (FgMyo5) and actin (FgAct), the targets of the fungicide phenamacril, and these interactions were reduced after phenamacril treatment. The deletion of FgPfn disrupted the normal organization of FgMyo5 and FgAct cytoskeleton, weakened the interaction between FgMyo5 and FgAct, and resulting in increased sensitivity to phenamacril. The core region of the interaction between FgPfn and FgAct was investigated, revealing that the integrity of both proteins was necessary for their interaction. Furthermore, mutations in R72, R77, R86, G91, I101, A112, G113, and D124 caused the non-interaction between FgPfn and FgAct. The R86K, I101E, and D124E mutants in FgPfn resulted in severe defects in actin organization, development, and pathogenicity. Taken together, this study revealed the role of FgPfn-dependent cytoskeleton in development, DON production and transport, fungicides sensitivity in F. graminearum.
Assuntos
Actinas , Proteínas Fúngicas , Fungicidas Industriais , Fusarium , Microtúbulos , Doenças das Plantas , Triticum , Microtúbulos/metabolismo , Fusarium/metabolismo , Fusarium/patogenicidade , Fusarium/genética , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Actinas/metabolismo , Doenças das Plantas/microbiologia , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Triticum/microbiologia , Fungicidas Industriais/farmacologia , Esporos Fúngicos/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , ReproduçãoRESUMO
Eukaryotic genomes are spatially organized within the nucleus in a nonrandom manner. However, fungal genome arrangement and its function in development and adaptation remain largely unexplored. Here, we show that the high-order chromosome structure of Fusarium graminearum is sculpted by both H3K27me3 modification and ancient genome rearrangements. Active secondary metabolic gene clusters form a structure resembling chromatin jets. We demonstrate that these jet-like domains, which can propagate symmetrically for 54 kb, are prevalent in the genome and correlate with active gene transcription and histone acetylation. Deletion of GCN5, which encodes a core and functionally conserved histone acetyltransferase, blocks the formation of the domains. Insertion of an exogenous gene within the jet-like domain significantly augments its transcription. These findings uncover an interesting link between alterations in chromatin structure and the activation of fungal secondary metabolism, which could be a general mechanism for fungi to rapidly respond to environmental cues, and highlight the utility of leveraging three-dimensional genome organization in improving gene transcription in eukaryotes.
Assuntos
Cromatina , Cromossomos Fúngicos , Fusarium , Metabolismo Secundário , Acetilação , Cromatina/metabolismo , Cromatina/genética , Cromossomos Fúngicos/genética , Cromossomos Fúngicos/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Fusarium/genética , Fusarium/metabolismo , Regulação Fúngica da Expressão Gênica , Genoma Fúngico , Histona Acetiltransferases/metabolismo , Histona Acetiltransferases/genética , Histonas/metabolismo , Histonas/genética , Família Multigênica , Metabolismo Secundário/genética , Transcrição GênicaRESUMO
Plant pathogens are challenged by host-derived iron starvation or excess during infection, but the mechanism through which pathogens counteract iron stress is unclear. Here, we found that Fusarium graminearum encounters iron excess during the colonization of wheat heads. Deletion of heme activator protein X (FgHapX), siderophore transcription factor A (FgSreA) or both attenuated virulence. Further, we found that FgHapX activates iron storage under iron excess by promoting histone H2B deubiquitination (H2B deub1) at the promoter of the responsible gene. Meanwhile, FgSreA is shown to inhibit genes mediating iron acquisition during iron excess by facilitating the deposition of histone variant H2A.Z and histone 3 lysine 27 trimethylation (H3K27 me3) at the first nucleosome after the transcription start site. In addition, the monothiol glutaredoxin FgGrx4 is responsible for iron sensing and control of the transcriptional activity of FgHapX and FgSreA via modulation of their enrichment at target genes and recruitment of epigenetic regulators, respectively. Taken together, our findings elucidated the molecular mechanisms for adaptation to iron excess mediated by FgHapX and FgSreA during infection in F. graminearum and provide novel insights into regulation of iron homeostasis at the chromatin level in eukaryotes.
Assuntos
Fusarium , Histonas , Ferro , Cromatina , Histonas/genética , Histonas/metabolismo , Ferro/metabolismo , Nucleossomos , Sideróforos/genética , Fusarium/metabolismoRESUMO
Fusarium graminearum is an economically important phytopathogenic fungus. Chemical control remains the dominant approach to managing this plant pathogen. In the present study, we performed a comparative transcriptome analysis to understand the effects of four commercially used fungicides on F. graminearum. The results revealed a significant number of differentially expressed genes related to carbohydrate, amino acid, and lipid metabolism, particularly in the carbendazim and phenamacril groups. Central carbon pathways, including the TCA and glyoxylate cycles, were found to play crucial roles across all treatments except tebuconazole. Weighted gene co-expression network analysis reinforced the pivotal role of central carbon pathways based on identified hub genes. Additionally, critical candidates associated with ATP-binding cassette transporters, heat shock proteins, and chitin synthases were identified. The crucial functions of the isocitrate lyase in F. graminearum were also validated. Overall, the study provided comprehensive insights into the mechanisms of how F. graminearum responds to fungicide stress.
Assuntos
Proteínas Fúngicas , Fungicidas Industriais , Fusarium , Transcriptoma , Fusarium/genética , Fusarium/metabolismo , Fungicidas Industriais/farmacologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Isocitrato Liase/genética , Isocitrato Liase/metabolismo , Regulação Fúngica da Expressão Gênica , Perfilação da Expressão GênicaRESUMO
Fusarium oxysporum f.sp. lycopersici is a phytopathogen which causes vascular wilt disease in tomato plants. The survival tactics of both pathogens and hosts depend on intricate interactions between host plants and pathogenic microbes. Iron-binding proteins (IBPs) and copper-binding proteins (CBPs) play a crucial role in these interactions by participating in enzyme reactions, virulence, metabolism, and transport processes. We employed high-throughput computational tools at the sequence and structural levels to investigate the IBPs and CBPs of F. oxysporum. A total of 124 IBPs and 37 CBPs were identified in the proteome of Fusarium. The ranking of amino acids based on their affinity for binding with iron is Glu > His> Asp > Asn > Cys, and for copper is His > Asp > Cys respectively. The functional annotation, determination of subcellular localization, and Gene Ontology analysis of these putative IBPs and CBPs have unveiled their potential involvement in a diverse array of cellular and biological processes. Three iron-binding glycosyl hydrolase family proteins, along with four CBPs with carbohydrate-binding domains, have been identified as potential effector candidates. These proteins are distinct from the host Solanum lycopersicum proteome. Moreover, they are known to be located extracellularly and function as enzymes that degrade the host cell wall during pathogen-host interactions. The insights gained from this report on the role of metal ions in plant-pathogen interactions can help develop a better understanding of their fundamental biology and control vascular wilt disease in tomato plants.
Assuntos
Cobre , Proteínas Fúngicas , Fusarium , Ferro , Proteoma , Solanum lycopersicum , Fusarium/metabolismo , Fusarium/química , Proteoma/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Solanum lycopersicum/microbiologia , Solanum lycopersicum/metabolismo , Ferro/metabolismo , Cobre/metabolismo , Cobre/química , Proteínas de Transporte/metabolismo , Proteínas de Transporte/química , Proteínas de Transporte/genética , Proteínas de Ligação ao Ferro/metabolismo , Proteínas de Ligação ao Ferro/química , Proteínas de Ligação ao Ferro/genética , Doenças das Plantas/microbiologia , Ligação ProteicaRESUMO
BACKGROUND: Fusarium graminearum and Fusarium avenaceum are two of the most important causal agents of Fusarium head blight (FHB) of wheat. They can produce mycotoxins that accumulate in infected wheat heads, including deoxynivalenol (DON) and enniatins (ENNs), produced by F. graminearum and F. avenaceum, respectively. While the role of DON as a virulence factor in F. graminearum toward wheat is well known, ENNs in F. avenaceum has been poorly explored. Results obtained to-date indicate that ENNs may confer an advantage to F. avenaceum only on particular hosts. RESULTS: In this study, with the use of ENN-producing and ENN non-producing F. avenaceum strains, the role of ENNs on F. avenaceum virulence was investigated on the root, stem base and head of common wheat, and compared with the role of DON, using DON-producing and DON non-producing F. graminearum strains. The DON-producing F. graminearum strain showed a significantly higher ability to cause symptoms and colonise each of the tested tissues than the non-producing strain. On the other hand, the ability to produce ENNs increased initial symptoms of the disease and fungal biomass accumulation, measured by qPCR, only in wheat heads, and not in roots or stem bases. LC-MS/MS analysis was used to confirm the presence of ENNs and DON in the different strains, and results, both in vitro and in wheat heads, were consistent with the genetics of each strain. CONCLUSION: While the key role of DON on F. graminearum virulence towards three different wheat tissues was noticeable, ENNs seemed to have a role only in influencing F. avenaceum virulence on common wheat heads probably due to an initial delay in the appearance of symptoms.
Assuntos
Fusarium , Doenças das Plantas , Tricotecenos , Triticum , Triticum/microbiologia , Triticum/metabolismo , Fusarium/patogenicidade , Fusarium/genética , Fusarium/metabolismo , Tricotecenos/metabolismo , Virulência , Doenças das Plantas/microbiologia , Micotoxinas/metabolismo , DepsipeptídeosRESUMO
Fungal non-ribosomal peptide synthetase (NRPS)-encoding products play a paramount role in new drug discovery. Fusarium, one of the most common filamentous fungi, is well-known for its biosynthetic potential of NRPS-type compounds with diverse structural motifs and various biological properties. With the continuous improvement and extensive application of bioinformatic tools (e.g., anti-SMASH, NCBI, UniProt), more and more biosynthetic gene clusters (BGCs) of secondary metabolites (SMs) have been identified in Fusarium strains. However, the biosynthetic logics of these SMs have not yet been well investigated till now. With the aim to increase our knowledge of the biosynthetic logics of NPRS-encoding products in Fusarium, this review firstly provides an overview of research advances in elucidating their biosynthetic pathways.
Assuntos
Fusarium , Fusarium/genética , Fusarium/metabolismo , Fungos/metabolismo , Peptídeo Sintases/genética , Peptídeo Sintases/metabolismo , Biologia Computacional , Família Multigênica , Vias Biossintéticas/genéticaRESUMO
Biosurfactants are in demand by the global market as natural commodities suitable for incorporation into commercial products or utilization in environmental applications. Fungi are promising producers of these molecules and have garnered interest also for their metabolic capabilities in efficiently utilizing recalcitrant and complex substrates, like hydrocarbons, plastic, etc. Within this framework, biosurfactants produced by two Fusarium solani fungal strains, isolated from plastic waste-contaminated landfill soils, were analyzed. Mycelia of these fungi were grown in the presence of 5% olive oil to drive biosurfactant production. The characterization of the emulsifying and surfactant capacity of these extracts highlighted that two different components are involved. A protein was purified and identified as a CFEM (common in fungal extracellular membrane) containing domain, revealing a good propensity to stabilize emulsions only in its aggregate form. On the other hand, an unidentified cationic smaller molecule exhibits the ability to reduce surface tension. Based on the 3D structural model of the protein, a plausible mechanism for the formation of very stable aggregates, endowed with the emulsifying ability, is proposed. KEY POINTS: ⢠Two Fusarium solani strains are analyzed for their surfactant production. ⢠A cationic surfactant is produced, exhibiting the ability to remarkably reduce surface tension. ⢠An identified protein reveals a good propensity to stabilize emulsions only in its aggregate form.
Assuntos
Proteínas Fúngicas , Fusarium , Tensoativos , Fusarium/metabolismo , Fusarium/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Tensoativos/metabolismo , Tensoativos/química , Emulsificantes/metabolismo , Emulsificantes/química , Microbiologia do Solo , Emulsões/química , Emulsões/metabolismo , Tensão Superficial , Cisteína/metabolismo , Cisteína/química , Azeite de Oliva/metabolismo , Azeite de Oliva/química , Micélio/metabolismoRESUMO
The biologically produced gold nanoparticles (AuNPs) are novel carriers with promising use in targeted tumor therapy. Still, there are no studies regarding the efficacy of nanoparticle internalization by cancer and noncancer cells. In this study, AuNPs were produced by Fusarium oxysporum and analyzed by spectrophotometry, transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and Zetasizer. Obtained AuNPs were about 15 nm in size with a zeta potential of -35.8 mV. The AuNPs were added to cancer cells (4T1), noncancer cells (NIH/3T3), and macrophages (RAW264.7). The viability decreased in 4T1 (77 ± 3.74%) in contrast to NIH/3T3 and RAW264.7 cells (89 ± 4.9% and 90 ± 3.5%, respectively). The 4T1 cancer cells also showed the highest uptake and accumulation of Au (â¼80% of AuNPs was internalized) as determined by graphite furnace atomic absorption spectroscopy. The lowest amount of AuNPs was internalized by the NIH/3T3 cells (â¼30%). The NIH/3T3 cells exhibited prominent reorganization of F-actin filaments as examined by confocal microscopy. In RAW264.7, we analyzed the release of proinflammatory cytokines by flow cytometry and we found the AuNP interaction triggered transient secretion of tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). In summary, we proved the biologically produced AuNPs entered all the tested cell types and triggered cell-specific responses. High AuNP uptake by tumor cells was related to decreased cell viability, while low nanoparticle uptake by fibroblasts triggered F-actin reorganization without remarkable toxicity. Thus, the biologically produced AuNPs hold promising potential as cancer drug carriers and likely require proper surface functionalization to shield phagocytizing cells.
Assuntos
Ouro , Nanopartículas Metálicas , Ouro/química , Ouro/metabolismo , Ouro/farmacologia , Animais , Camundongos , Nanopartículas Metálicas/química , Células NIH 3T3 , Células RAW 264.7 , Sobrevivência Celular/efeitos dos fármacos , Fusarium/metabolismo , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacosRESUMO
Fusarium proliferatum is the main pathogen that causes Panax notoginseng root rot. The shortcomings of strong volatility and poor water solubility of Illicium verum essential oil (EO) limit its utilization. In this study, we prepared traditional emulsion (BDT) and nanoemulsion (Bneo) of I. verum EO by ultrasonic method with Tween-80 and absolute ethanol as solvents. The chemical components of EO, BDT, and Bneo were identified by gas chromatography-mass spectrometry (GC-MS) and the antifungal activity and mechanism were compared. The results show that Bneo has good stability and its particle size is 34.86 nm. The contents of (-) -anethole and estragole in Bneo were significantly higher than those in BDT. The antifungal activity against F. proliferatum was 5.8-fold higher than BDT. In the presence of I. verum EO, the occurrence of P. notoginseng root rot was significantly reduced. By combining transcriptome and metabolomics analysis, I. verum EO was found to be involved in the mutual transformation of pentose and glucuronic acid, galactose metabolism, streptomycin biosynthesis, carbon metabolism, and other metabolic pathways of F. proliferatum, and it interfered with the normal growth of F. proliferatum to exert antifungal effects. This study provide a theoretical basis for expanding the practical application of Bneo.
Assuntos
Antifúngicos , Emulsões , Fusarium , Illicium , Metabolômica , Óleos Voláteis , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Fusarium/efeitos dos fármacos , Fusarium/genética , Fusarium/metabolismo , Illicium/química , Antifúngicos/farmacologia , Antifúngicos/metabolismo , Antifúngicos/química , Emulsões/química , Transcriptoma , Cromatografia Gasosa-Espectrometria de Massas , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Perfilação da Expressão GênicaRESUMO
The current study aimed to evaluate the plant growth-promoting (PGP) potential of endophytic strain Bacillus subtilis KU21 isolated from the roots of Rosmarinus officinalis. The strain exhibited multiple traits of plant growth promotion viz., phosphate (P) solubilization, nitrogen fixation, indole-3-acetic acid (IAA), siderophore, hydrogen cyanide (HCN), lytic enzymes production, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. The isolate also exhibited antagonistic activity against phytopathogenic fungi, i.e., Fusarium oxysporum, Fusarium graminiarum, and Rhizoctonia solani. The P-solubilization activity of B. subtilis KU21 was further elucidated via detection of glucose dehydrogenase (gdh) gene involved in the production of gluconic acid which is responsible for P-solubilization. Further, B. subtilis KU21 was evaluated for in vivo growth promotion studies of tomato (test crop) under net house conditions. A remarkable increase in seed germination, plant growth parameters, nutrient acquisition, and soil quality parameters (NPK) was observed in B. subtilis KU21-treated plants over untreated control. Hence, the proposed module could be recommended for sustainable tomato production in the Northwest Himalayan region without compromising soil health and fertility.
Assuntos
Bacillus subtilis , Endófitos , Raízes de Plantas , Rosmarinus , Bacillus subtilis/genética , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/isolamento & purificação , Bacillus subtilis/metabolismo , Endófitos/isolamento & purificação , Endófitos/metabolismo , Endófitos/genética , Endófitos/classificação , Rosmarinus/química , Rosmarinus/microbiologia , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Solanum lycopersicum/microbiologia , Solanum lycopersicum/crescimento & desenvolvimento , Fusarium/crescimento & desenvolvimento , Fusarium/genética , Fusarium/metabolismo , Microbiologia do Solo , Desenvolvimento Vegetal , Germinação , Ácidos Indolacéticos/metabolismo , Rhizoctonia/crescimento & desenvolvimento , Rhizoctonia/efeitos dos fármacos , Fixação de Nitrogênio , Fosfatos/metabolismoRESUMO
In current study, Fusarium mycotoxin, beauvericin (BEA), has endocrine disrupting potential through suppressing the exogenous androgen receptor (AR)-mediated transcriptional activation. BEA was classified as an AR antagonist, with IC30 and IC50 values indicating that it suppressed AR dimerization in the cytosol. BEA suppress the translocation of cytosolic activated ARs to the nucleus via exogenous androgens. Furthermore, we investigated the impact of environmental conditions for BEA production on rice cereal using response surface methodology. The environmental factors affecting the production of BEA, namely temperature, initial moisture content, and growth time were optimized at 20.28 °C, 42.79 % (w/w), and 17.31 days, respectively. To the best of our knowledge, this is the first report showing that BEA has endocrine disrupting potential through suppressing translocation of cytosolic ARs to nucleus, and temperature, initial moisture content, and growth time are important influencing environmental factors for its biosynthesis in Fusarium strains on cereal.
Assuntos
Depsipeptídeos , Fusarium , Micotoxinas , Oryza , Receptores Androgênicos , Humanos , Depsipeptídeos/toxicidade , Grão Comestível/química , Fusarium/metabolismo , Micotoxinas/toxicidade , Oryza/química , Receptores Androgênicos/efeitos dos fármacos , Receptores Androgênicos/metabolismo , Disruptores Endócrinos/química , Disruptores Endócrinos/toxicidadeRESUMO
The compound 15-deacetylcalonectrin (15-deCAL) is a common pathway intermediate in the biosynthesis of Fusarium trichothecenes. This tricyclic intermediate is metabolized to calonectrin (CAL) by trichothecene 15-O-acetyltransferase encoded by Tri3. Unlike other trichothecene pathway Tri gene mutants, the Δtri3 mutant produces lower amounts of the knocked-out enzyme's substrate 15-deCAL, and instead, accumulates higher quantities of earlier bicyclic intermediate and shunt metabolites. Furthermore, evolutionary studies suggest that Tri3 may play a role in shaping the chemotypes of trichothecene-producing Fusarium strains. To better understand the functional role of Tri3p in biosynthesis and evolution, we aimed to develop a method to produce 15-deCAL by using transgenic Fusarium graminearum strains derived from a trichothecene overproducer. Unfortunately, introducing mutant Tri3, encoding a catalytically impaired but structurally intact acetylase, did not improve the low 15-deCAL production level of the ΔFgtri3 deletion strain, and the bicyclic products continued to accumulate as the major metabolites of the active-site mutant. These findings are discussed in light of the enzyme responsible for 15-deCAL production in trichothecene biosynthesis machinery. To efficiently produce 15-deCAL, we tested an alternative strategy of using a CAL-overproducing transformant. By feeding a crude CAL extract to a Fusarium commune strain that was isolated in this study and capable of specifically deacetylating C-15 acetyl, 15-deCAL was efficiently recovered. The substrate produced in this manner can be used for kinetic investigations of this enzyme and its possible role in chemotype diversification.
Assuntos
Fusarium , Mutação , Tricotecenos , Fusarium/genética , Fusarium/metabolismo , Tricotecenos/metabolismo , Acetiltransferases/metabolismo , Acetiltransferases/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Vias Biossintéticas/genéticaRESUMO
The trichothecene biosynthesis in Fusarium begins with the cyclization of farnesyl pyrophosphate to trichodiene, followed by subsequent oxygenation to isotrichotriol. This initial bicyclic intermediate is further cyclized to isotrichodermol (ITDmol), a tricyclic precursor with a toxic trichothecene skeleton. Although the first cyclization and subsequent oxygenation are catalyzed by enzymes encoded by Tri5 and Tri4, the second cyclization occurs non-enzymatically. Following ITDmol formation, the enzymes encoded by Tri101, Tri11, Tri3, and Tri1 catalyze 3-O-acetylation, 15-hydroxylation, 15-O-acetylation, and A-ring oxygenation, respectively. In this study, we extensively analyzed the metabolites of the corresponding pathway-blocked mutants of Fusarium graminearum. The disruption of these Tri genes, except Tri3, led to the accumulation of tricyclic trichothecenes as the main products: ITDmol due to Tri101 disruption; a mixture of isotrichodermin (ITD), 7-hydroxyisotrichodermin (7-HIT), and 8-hydroxyisotrichodermin (8-HIT) due to Tri11 disruption; and a mixture of calonectrin and 3-deacetylcalonectrin due to Tri1 disruption. However, the ΔFgtri3 mutant accumulated substantial amounts of bicyclic metabolites, isotrichotriol and trichotriol, in addition to tricyclic 15-deacetylcalonectrin (15-deCAL). The ΔFgtri5ΔFgtri3 double gene disruptant transformed ITD into 7-HIT, 8-HIT, and 15-deCAL. The deletion of FgTri3 and overexpression of Tri6 and Tri10 trichothecene regulatory genes did not result in the accumulation of 15-deCAL in the transgenic strain. Thus, the absence of Tri3p and/or the presence of a small amount of 15-deCAL adversely affected the non-enzymatic second cyclization and C-15 hydroxylation steps.
Assuntos
Fusarium , Tricotecenos , Fusarium/metabolismo , Fusarium/genética , Ciclização , Tricotecenos/metabolismo , Acetilação , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Fosfatos de Poli-Isoprenil/metabolismo , Vias BiossintéticasRESUMO
This study aimed to evaluate how the combined presence of the synthetic fungicide azoxystrobin (AZ) and the biosurfactant-producing Bacillus sp. Kol B3 influences the growth of the phytopathogenic fungus Fusarium sambucinum IM 6525. The results showed a noticeable increase in antifungal effectiveness when biotic and abiotic agents were combined. This effect manifested across diverse parameters, including fungal growth inhibition, changes in hyphae morphology, fungal membrane permeability and levels of intracellular reactive oxygen species (ROS). In response to the presence of Fusarium and AZ in the culture, the bacteria changed the proportions of biosurfactants (surfactin and iturin) produced. The presence of both AZ and/or Fusarium resulted in an increase in iturin biosynthesis. Only in 72 h old bacterial-fungal co-culture a 20% removal of AZ was noted. In the fungal cultures (with and without the addition of the bacteria), the presence of an AZ metabolite named azoxystrobin free acid was detected in the 48th and 72nd hours of the process. The possible involvement of increased iturin and ROS content in antifungal activity of Bacillus sp. and AZ when used together are also discussed. Biosurfactants were analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Microscopy techniques and biochemical assays were also used.
Assuntos
Antifúngicos , Bacillus , Fusarium , Pirimidinas , Estrobilurinas , Tensoativos , Estrobilurinas/farmacologia , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Fusarium/metabolismo , Bacillus/metabolismo , Tensoativos/farmacologia , Tensoativos/metabolismo , Antifúngicos/farmacologia , Pirimidinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Testes de Sensibilidade MicrobianaRESUMO
Heme biosynthesis is a highly conserved pathway from bacteria to higher animals. Heme, which serves as a prosthetic group for various enzymes involved in multiple biochemical processes, is essential in almost all species, making heme homeostasis vital for life. However, studies on the biological functions of heme in filamentous fungi are scarce. In this study, we investigated the role of heme in Fusarium graminearum. A mutant lacking the rate-limiting enzymes in heme synthesis, coproporphyrinogen III oxidase (Cpo) or ferrochelatase (Fc), was constructed using a homologous recombination strategy. The results showed that the absence of these enzymes was lethal to F. graminearum, but the growth defect could be rescued by the addition of hemin, so we carried out further studies with the help of hemin. The results demonstrated that heme was required for the activity of FgCyp51, and its absence increased the sensitivity to tebuconazole and led to the upregulation of FgCYP51 in F. graminearum. Additionally, heme plays an indispensable role in the life cycle of F. graminearum, which is essential for vegetative growth, conidiation, external stress response (especially oxidative stress), lipid accumulation, fatty acid ß-oxidation, autophagy, and virulence.
Assuntos
Fusarium , Heme , Fusarium/efeitos dos fármacos , Fusarium/metabolismo , Fusarium/crescimento & desenvolvimento , Fusarium/genética , Heme/biossíntese , Heme/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Estresse Fisiológico , Estresse Oxidativo/efeitos dos fármacos , Triazóis/farmacologia , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Ferroquelatase/metabolismo , Ferroquelatase/genéticaRESUMO
BACKGROUND: Fresh ginseng is typically accompanied by soil after harvest, leading to contamination with harmful fungi during storage and distribution. In this study, we investigated the incidence of fungal contamination in fresh ginseng (5-6 years old) purchased from 22 different stores in Geumsan, Korea. RESULTS: The incidence of fungal contamination in the samples was 67.4-111.5%. Fusarium solani was the most abundant species in the head (38.5%) and fine root (19.3%) parts of the ginseng samples, whereas F. oxysporum was the most abundant in the main root (22.0%) part. We isolated Aspergillus, Fusarium and Penicillium spp. (total number of isolates: 395) from the ginseng samples, and 138 isolates were identified using phylogenetic analysis. Polymerase chain reaction-based screening of 65 mycotoxin-producing species revealed that two P. expansum isolates were positive for citrinin and/or patulin, and five F. oxysporum isolates were positive for fumonisin biosynthesis gene. One P. expansum isolate produced 738.0 mg kg-1 patulin, and the other produced 10.4 mg kg-1 citrinin and 12.0 mg kg-1 patulin on potato dextrose agar (PDA) medium. Among the 47 representative F. oxysporum isolates, 43 (91.5%) produced beauvericin (0.1-15.4 mg kg-1) and four of them (8.5%) produced enniatin B and enniatin B1 (0.1-1.8 mg kg-1) as well. However, none of these toxins was detected in fresh ginseng samples. CONCLUSION: Fusarium solani and F. oxysporum were the most abundant species in fresh ginseng samples. Most F. oxysporum (43) and P. expansum (2) strains isolated from fresh ginseng produced beauvericin and enniatins (B and B1), and patulin or citrinin, respectively, on PDA medium. This is the first report of the mycotoxigenic potential of P. expansum and F. oxysporum strains isolated from fresh ginseng. © 2024 Society of Chemical Industry.
Assuntos
Contaminação de Alimentos , Fungos , Fusarium , Micotoxinas , Panax , Panax/microbiologia , Panax/química , Micotoxinas/metabolismo , Micotoxinas/análise , Fusarium/isolamento & purificação , Fusarium/metabolismo , Fusarium/genética , Fusarium/classificação , República da Coreia , Contaminação de Alimentos/análise , Fungos/isolamento & purificação , Fungos/genética , Fungos/classificação , Fungos/metabolismo , Filogenia , Aspergillus/isolamento & purificação , Aspergillus/metabolismo , Aspergillus/genética , Aspergillus/classificação , Penicillium/isolamento & purificação , Penicillium/metabolismo , Penicillium/classificação , Penicillium/genética , Raízes de Plantas/microbiologiaRESUMO
In past few years, salinity has become one of the important abiotic stresses in the agricultural fields due to anthropogenic activities. Salinity is leading towards yield losses due to soil infertility and increasing vulnerability of crops to diseases. Fluorescent pseudomonads are a diverse group of soil microorganisms known for promoting plant growth by involving various traits including protecting crops from infection by the phytopathogens. In this investigation, salt tolerant plant growth promoting bacterium Pseudomonas hunanensis SPT26 was selected as an antagonist against Fusarium oxysporum, causal organism of fusarium wilt in tomato. P. hunanensis SPT26 was found capable to produce various antifungal metabolites. Characterization of purified metabolites using Fourier transform infrared spectroscopy (FT-IR) and liquid chromatography-electron spray ionization-mass spectrometry (LC-ESI/MS) showed the production of various antifungal compounds viz., pyrolnitrin, pyochelin and hyroxyphenazine by P. hunanensis SPT26. In the preliminary examination, biocontrol activity of purified antifungal metabolites was checked by dual culture method and results showed 68%, 52% and 65% growth inhibition by pyrolnitrin, 1- hydroxyphenazine and the bacterium (P. hunanensis SPT26) respectively. Images from scanning electron microscopy (SEM) revealed the damage to the mycelia of fungal phytopathogen due to production of antifungal compounds secreted by P. hunanensis SPT26. Application of bioinoculant of P. hunanensis SPT26 and purified metabolites significantly decreased the disease incidence in tomato and increased the plant growth parameters (root and shoot length, antioxidant activity, number of fruits per plant, etc.) under saline conditions. The study reports a novel bioinoculant formulation with the ability to promote plant growth parameters in tomato in presence of phytopathogens even under saline conditions.
Assuntos
Antifúngicos , Fusarium , Doenças das Plantas , Pseudomonas , Solanum lycopersicum , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Fusarium/metabolismo , Solanum lycopersicum/microbiologia , Solanum lycopersicum/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Pseudomonas/metabolismo , Antifúngicos/farmacologia , Antifúngicos/metabolismo , Salinidade , Agentes de Controle Biológico/metabolismo , Agentes de Controle Biológico/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Microbiologia do Solo , Raízes de Plantas/microbiologiaRESUMO
The demand for environment-friendly cleanup techniques has arisen due to an increase in environmental pollutants. Fungi is the most prevalent and effective class of heavy metal-resistant microorganisms with the ability to leach metals. The objective of the present study was to isolate the fungi from the agricultural soil of Kashmir valley, investigate their multi-metal tolerance to heavy metals and evaluate the metal uptake capacities of the resistant fungi. The fungi were isolated and identified on the basis of morphological and molecular approach (ITS1 and ITS4). The tolerance limits of the isolated fungal strains to various doses of lead (Pb), cadmium (Cd), zinc (Zn), chromium (Cr), copper (Cu), nickel (Ni), and cobalt (Co) was evaluated. Five fungal strains, Aspergillus niger, Fusarium oxysporum, Fusarium verticillioides, Aspergillus fischeri, Epicoccum mackenziei were isolated from the soil samples. To the best of our knowledge, this is the first report on the study of metal resistance of Aspergillus fischeri and Epicoccum mackenziei. Among the identified fungal species, Aspergillus niger and Fusarium oxysporum were found to be most tolerant with a minimum inhibitory concentration (MIC) of 600 ppm against Cu and Cr respectively. Results indicated removal of considerable amount of heavy metals by some of the fungi. The highest metal uptake of 8.31 mg/g was found in Fusarium verticillioides for Zn. Surprisingly, these fungal strains demonstrated resistance to metal concentrations above the levels that are universally acceptable for polluted soils, and hence prove to be appealing contenders for use as bioremediation agents for cleaning up heavy metal-polluted environments.