Filamentous Fungus Fusarium Research Articles

Comparative efficacy of amino acid availability and peptidomic analysis of alternative proteins from different sources under dynamic in vitro protein digestion

The increasing global demand for animal protein highlights the critical necessity of exploring alternative protein sources. Accessing the nutritional characteristics of emerging alternative proteins is vital for food processing and consumer acceptance. This study investigated the amino acid availability and peptidomics profiles of plant- (soy), fungal- (filamentous fungus Fusarium venenatum), microalgae- (Nannochloropsis oculata), and insect-based (black soldier fly) proteins using an advanced dynamic in vitro digestion system, with whey protein as a reference. After gastric digestion, soy and mycelial proteins, despite displaying distinct microstructures, exhibited slightly higher protein digestibility levels of 28.79% and 26.36%, respectively, compared to whey protein (22.39%). However, following small intestinal digestion, whey protein (61.31%) significantly outperformed alternative proteins. Mycelial protein (43.71%) exhibited digestibility similar to soy protein (46.12%), markedly surpassing both microalgae protein (33.35%) and insect protein (26.58%). Notably, insect protein achieved an amino acid availability nearly approaching that of whey protein, underscoring its substantial proteolysis capability. Furthermore, microalgae protein produced the highest percentage and number of bioactive peptides under simulated digestion, suggesting potential health benefits such as angiotensin I-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibitor activities, which could mitigate the risk of hypertension and Type 2 diabetes. Alternative proteins from different sources demonstrate diverse digestive mechanisms and proteolysis profiles, thereby bolstering their potential applications as nutritious food ingredients in the future.

FgPfn participates in vegetative growth, sexual reproduction, pathogenicity, and fungicides sensitivity via affecting both microtubules and actin in the filamentous fungus Fusarium graminearum.

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 Fgβ2, 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.

Phylogenetic and functional analyses of N6-methyladenosine RNA methylation factors in the wheat scab fungus Fusarium graminearum.

In eukaryotes, N6-methyladenosine (m6A) RNA modification plays a crucial role in governing the fate of RNA molecules and has been linked to various developmental processes. However, the phyletic distribution and functions of genetic factors responsible for m6A modification remain largely unexplored in fungi. To get insights into the evolution of m6A machineries, we reconstructed global phylogenies of potential m6A writers, readers, and erasers in fungi. Substantial copy number variations were observed, ranging from up to five m6A writers in early-diverging fungi to a single copy in the subphylum Pezizomycotina, which primarily comprises filamentous fungi. To characterize m6A factors in a phytopathogenic fungus Fusarium graminearum, we generated knockout mutants lacking potential m6A factors including the sole m6A writer MTA1. However, the resulting knockouts did not exhibit any noticeable phenotypic changes during vegetative and sexual growth stages. As obtaining a homozygous knockout lacking MTA1 was likely hindered by its essential role, we generated MTA1-overexpressing strains (MTA1-OE). The MTA1-OE5 strain showed delayed conidial germination and reduced hyphal branching, suggesting its involvement during vegetative growth. Consistent with these findings, the expression levels of MTA1 and a potential m6A reader YTH1 were dramatically induced in germinating conidia, followed by the expression of potential m6A erasers at later vegetative stages. Several genes including transcription factors, transporters, and various enzymes were found to be significantly upregulated and downregulated in the MTA1-OE5 strain. Overall, our study highlights the functional importance of the m6A methylation during conidial germination in F. graminearum and provides a foundation for future investigations into m6A modification sites in filamentous fungi.IMPORTANCEN6-methyladenosine (m6A) RNA methylation is a reversible posttranscriptional modification that regulates RNA function and plays a crucial role in diverse developmental processes. This study addresses the knowledge gap regarding phyletic distribution and functions of m6A factors in fungi. The identification of copy number variations among fungal groups enriches our knowledge regarding the evolution of m6A machinery in fungi. Functional characterization of m6A factors in a phytopathogenic filamentous fungus Fusarium graminearum provides insights into the essential role of the m6A writer MTA1 in conidial germination and hyphal branching. The observed effects of overexpressing MTA1 on fungal growth and gene expression patterns of m6A factors throughout the life cycle of F. graminearum further underscore the importance of m6A modification in conidial germination. Overall, this study significantly advances our understanding of m6A modification in fungi, paving the way for future research into its roles in filamentous growth and potential applications in disease control.

Identification of Fungal and Bacterial Denitrification Inhibitors Targeting Copper Nitrite Reductase.

The usage of nitrification inhibitors is one of the strategies that reduce or slow down the denitrification process to prevent nitrogen loss to the atmosphere in the form of N2O. Directly targeting microbial denitrification could be one of the mitigation strategies; however, until now little efforts have been devoted toward the development of denitrification inhibitors. Here, we have identified small-molecule inhibitors of one of the proteins involved in the fungal denitrification pathway. Specifically, virtual screening was employed to identify the inhibitors of copper-containing nitrite reductase (FoNirK) of the filamentous fungus Fusarium oxysporum. Three series of chemical compounds were identified, out of which compounds belonging to two chemical scaffolds inhibited FoNirK enzymatic activity in low micromolar ranges. Several compounds also displayed moderate inhibition of fungal denitrification activity in vivo. Evaluation of in vitro activity against NirK from denitrifying bacterium Achromobacter xylosoxidans (AxNirK) and in vivo bacterial denitrification revealed a similar inhibitory profile.

Constitutive activation of TORC1 signalling attenuates virulence in the cross-kingdom fungal pathogen Fusarium oxysporum.

The filamentous fungus Fusarium oxysporum causes vascular wilt disease in a wide range of plant species and opportunistic infections in humans. Previous work suggested that invasive growth in this pathogen is controlled by environmental cues such as pH and nutrient status. Here we investigated the role of Target Of Rapamycin Complex 1 (TORC1), a global regulator of eukaryotic cell growth and development. Inactivation of the negative regulator Tuberous Sclerosis Complex 2 (Tsc2), but not constitutive activation of the positive regulator Gtr1, in F.oxysporum resulted in inappropriate activation of TORC1 signalling under nutrient-limiting conditions. The tsc2Δ mutants showed reduced colony growth on minimal medium with different nitrogen sources and increased sensitivity to cell wall or high temperature stress. Furthermore, these mutants were impaired in invasive hyphal growth across cellophane membranes and exhibited a marked decrease in virulence, both on tomato plants and on the invertebrate animal host Galleria mellonella. Importantly, invasive hyphal growth in tsc2Δ strains was rescued by rapamycin-mediated inhibition of TORC1. Collectively, these results reveal a key role of TORC1 signalling in the development and pathogenicity of F.oxysporum and suggest new potential targets for controlling fungal infections.

Gap-Free Nuclear and Mitochondrial Genomes of Fusarium verticillioides Strain HN2

Fusarium ear rot (FER) and Fusarium stalk rot (FSR), caused by the filamentous fungus Fusarium verticillioides, have become increasingly serious around the world. Additionally, fumonisins produced by F. verticillioides threaten food and feed security. By adding the contribution of genomic resources to better understand the pathosystem, including the mechanisms of F. verticillioides-maize interactions, and further improving the quality of the F. verticillioides genome, the gap-free nuclear genome and mitochondrial genome of F. verticillioides strain HN2 were sequenced and assembled. Using Oxford Nanopore long reads and next-generation sequencing short reads, the final 42.81-Mb genome was assembled into 12 contigs (N50 = 4.16 Mb). A total of 13,466 protein-coding genes were annotated, including 1,076 secreted proteins that contain 342 candidate effectors. In addition, we assembled the complete 53,764-bp mitochondrial genome. F. verticillioides strain 7600 genome assemblies are fragmented, and high-quality reference genomes were needed. The genomes presented here will serve as an important resource for F. verticillioides research. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Determination of the inhibitory activity of silver nanoparticles against some pathogenic multi-antibiotic resistant bacterial species

The study was done to determine the inhibitory effect of silver nanoparticles synthesed by the filamentous fungus Fusarium mangiferae against some multidrugs resistant pathogenic bacteria which were taken from the Central Laboratory of Sulaymaniyah Teaching Hospital.Silver nanoparticles showed their inhibitory effect on the various bacterial species in this study by two methods Wich are the well diffusion method and inhibition growth. Nanoparticles of silver showed inhibitory areas by Well diffusion method against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Proteus mirabilis.
 The Diameter of inhibition zones of the above mentioned bacteria were (15.25, 20.5, 17.75.16) mm while The method of inhibition of growth had shown that nanoparticles effective against the above bacterial species at concentrations (50, 50, 50, 100)% respectively through the lack of growth of the colonies on the surface of the nutrient agar. Therefore, the use of nanoparticles from some metals is the best solution for the treatment of infectious diseases due to the effective inhibiting properties of these nanoparticles against bacteria without negative side effects.

Genome Sequence Resource of Fusarium graminearum TaB10 and Fusarium avenaceum KA13, Causal Agents of Stored Apple Rot.

The filamentous fungus Fusarium graminearum is a well-known cereal pathogen and F. avenaceum is a pathogen with a wide host range. Recently, both species were reported as causal agents of apple rot, raising concerns about postharvest yield losses and mycotoxin contamination. Here, we report genome assemblies of F. avenaceum KA13 and F. graminearum TaB10, both isolated from fruits with symptoms of apple rot. The final F. avenaceum KA13 genome sequence assembly of 41.7 Mb consists of 34 scaffolds, with an N50 value of 2.2 Mb and 15,886 predicted genes. The total size of the final F. graminearum TaB10 assembly is 36.76 Mb, consisting of 54 scaffolds with an N50 value of 1.7 Mb, and it consists of 14,132 predicted genes. These new genomes provide valuable resources to better understand plant-microbe interaction in stored apple rot disease. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Fusarium graminearum Ste3 G-Protein Coupled Receptor: A Mediator of Hyphal Chemotropism and Pathogenesis.

Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Previous studies on Fusarium species have highlighted the involvement of the Ste2 G-protein-coupled receptor (GPCR) in mediating polarized hyphal growth toward host-released peroxidase. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to Fusarium graminearum chemotropism and pathogenicity. Fgste3Δ deletion strains were found to be compromised in the chemotropic response toward peroxidase, development of lesions on germinating wheat, and infection of Arabidopsis thaliana leaves. In the absence of FgSte3 or FgSte2, F. graminearum cells exposed to peroxidase showed no phosphorylation of the cell-wall integrity, mitogen-activated protein kinase pathway component Mgv1. In addition, transcriptomic gene expression profiling yielded a list of genes involved in cellular reorganization, cell wall remodeling, and infection-mediated responses that were differentially modulated by peroxidase when FgSte3 was present. Deletion of FgSte3 yielded the downregulation of genes associated with mycotoxin biosynthesis and appressorium development, compared to the wild-type strain, both in the presence of peroxidase. Together, these findings contribute to our understanding of the mechanism underlying fungal chemotropism and pathogenesis while raising the novel hypothesis that FgSte2 and FgSte3 are interdependent on each other for the mediation of the redirection of hyphal growth in response to host-derived peroxidase. IMPORTANCE Fusarium head blight of wheat, caused by the filamentous fungus Fusarium graminearum, leads to devastating global food shortages and economic losses. Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to F. graminearum chemotropism and pathogenicity. These findings contribute to our understanding of the mechanisms underlying fungal chemotropism and pathogenesis.

Antimicrobial and Antibiofilm Activity of Biosynthesized Silver Nanoparticles Against Beta-lactamase-Resistant Enterococcus faecalis.

Due to the presence of antibiotic-resistant genes, treatment options of clinical isolates are exceedingly limited. This study was aimed to fabricate, optimize, characterize, and evaluate the action of silver nanoparticles (AgNPs) against a clinical isolate of Enterococcus faecalis. A combination of cell-free supernatant (C-FS) of the filamentous fungus Fusarium solani and Gram-negative Comamonas aquatica for AgNP formation was proposed; the antigrowth and antibiofilm of AgNPs against E. faecalis harboring blaTEM and blaCTX-M genes were assessed. The ratio of 1:2 v/v (C-FS:AgNO3) at pH 9.0 for 72h in 1mM AgNO3 were the optimal conditions for AgNP formation. UV-vis absorption peak appeared at 425nm and the crystalline nature of synthesized particles was verified by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the interaction of protein molecules with the AgNPs. Transmission electron microscopy (TEM) analysis demonstrated that fabricated AgNPs were relatively monodispersed, approximately spherical, and of size 2-7.5nm. blaTEM and blaCTX-M were detected in E. faecalis; the growth and biofilm of E. faecalis were significantly decreased by the action of 12.5μg/mL AgNPs. This is the first study proposing alternative sources to form AgNPs via synergistic metabolites of F. solani and C. aquatica. The results here offer a foundation for developing an effective therapy using AgNPs against clinical pathogens.

Draft Genome Resources for Brassicaceae Pathogens Fusarium oxysporum f. sp. raphani and Fusarium oxysporum f. sp. rapae.

The soilborne filamentous fungus Fusarium oxysporum causes devastating diseases of many cultivated plant species. F. oxysporum f. sp. raphani and f. sp. rapae are two of four formae speciales that are pathogenic to Brassicaceae plants. Here, we present high-quality genome sequences of F. oxysporum f. sp. raphani strain Tf1262 and F. oxysporum f. sp. rapae strain Tf1208 that were isolated from radish (Raphanus sativus) and turnip (Brassica rapa var. rapa), respectively. These genome resources should facilitate in-depth investigation of interactions between F. oxysporum and Brassicaceae plants, and enable comparative genomics of the F. oxysporum species complex to uncover how pathogenicity evolved within F. oxysporum.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Biodegradation of 2,5‐dimethylpyrazine in gas and liquid phase by the fungus Fusarium solani

AbstractBACKGROUNDAlkylpyrazines are odorous compounds conferring pleasant aromas to baked and roasted foods. However, they are also emitted during food processing, creating a nuisance for the operators and the community. Only a few bacterial isolates have been shown to degrade 2,5‐methylpyrazine (DMP), as a model alkylpyrazine. This work aimed to study the ability of DMP biodegradation by the filamentous fungus Fusarium solani.RESULTSEvidence of the degradation of DMP was collected in axenic cultures of F. solani in liquid mineral medium and over a saturated solid support using DMP as the sole carbon and energy source. DMP was used for growth as evidenced by the formation of an abundant aerial mycelium over a solid support, accompanied by the production of 70 ppm CO2 mg−1 dry biomass, and by its consumption in liquid media at a rate of 58.3 mg g−1 biomass h−1, a value comparable to those reported for bacteria. A non‐axenic biofilter was mounted, fed with a DMP‐laden air stream, and operated for 40 days. The maximum DMP elimination capacity achieved was 8.5 g m−3 h−1 at an inlet load of 11.3 g m−3 h−1 (an 80% relative efficiency).CONCLUSIONFusarium solani uses DMP as a carbon source, showing great potential for its abatement in a biofilter. High‐throughput DNA sequencing of biofilter samples showed that it was the most representative member of the community, with a relative abundance surpassing 97%, indicating that it played a pivotal role in the biofilter. © 2021 Society of Chemical Industry (SCI).

Degradation of the antifungal pharmaceutical clotrimazole by UVC and vacuum-UV irradiation: Kinetics, transformation products and attenuation of toxicity

Azole fungicides are frequently detected as water contaminants due to extensive societal use, and these broad-spectrum antifungal chemicals can cause harmful effects in non-target organisms. Vacuum ultraviolet (VUV) treatment is an efficient and green technology that produces hydroxyl radical to remove contaminants from water. This study investigated the potential of UVC (254 nm) and combined VUV/UVC (185/254 nm) treatment to remove the widely used antifungal compound clotrimazole from water. Degradation kinetics, degradation mechanisms, and toxicity mitigation were investigated using a VUV photoreactor. Toxicity of clotrimazole to aquatic organisms before and after UV treatment were investigated using the luminescent bacterium Aliivibrio fischeri, the bioluminescent yeast Saccharomyces cerevisiae BLYR, the filamentous fungus Fusarium graminearum, the freshwater microalga Raphidocelis subcapitata, and the crustacean Daphnia magna. VUV irradiation efficiently degraded the persistent pollutant clotrimazole at elevated concentrations (mg/L) and at environmental concentrations (µg/L) with > 50% abatement in 1 min and > 95% removal within 32 min. VUV photolysis produced 8 transformation products manly resulting from drug hydroxylation in the phenyl ring and/or imidazole group followed by ring opening or loss of the imidazole moiety. Substantial decrease in aquatic toxicity was observed after UV treatment suggesting that VUV irradiation of aqueous clotrimazole generated less-toxic transformation products.

Farfantepenaeus gene-encoded antimicrobial peptides: Identification, molecular characterization and gene expression in response to fungal infections

The aim of this study was to identify and characterize, at the molecular and transcriptional levels, sequences encoding the different members of the four families of shrimp antimicrobial peptides (AMPs) in species of the genus Farfantepenaeus. The identification of the AMP sequences was performed by in silico analysis as well as by molecular cloning and nucleotide sequencing. We identified all seven shrimp ALFs (ALF-A to ALF-G), both Type IIa and Type IIb crustins as well as two stylicins (STY1 and STY2) in Farfantepenaeus. Only two genes (PEN1/2 and PEN4) of the four-member penaeidin family (PEN1/2 to PEN5) were found and this is the first report of stylicins as well as of several additional members of ALFs, crustins and penaeidins in species of the genus Farfantepenaeus. All AMP genes have shown to be constitutively transcribed in the shrimp immune cells (hemocytes), except for ALF-G. Finally, the transcriptional profile of the different AMPs was assessed in the hemocytes of F. paulensis (pink shrimp) following an experimental infection with the opportunistic filamentous fungus Fusarium solani. We found that while the expression of ALF-B was induced at 24 h, the STY2 gene was down-regulated at 48 h post-challenge. These results provide evidence of the molecular diversity of AMPs from shrimp of the genus Farfantepenaeus in terms of sequences, biochemical properties and expression profiles in response to infectious diseases.

Cu transporter protein CrpF protects against Cu-induced toxicity in Fusarium oxysporum

ABSTRACT Cu is an essential trace element for cell growth and proliferation. However, excess of Cu accumulation leads to cellular toxicity. Thus, precise and tight regulation of Cu homeostasis processes, including transport, delivery, storage, detoxification, and efflux machineries, is required. Moreover, the maintenance of Cu homeostasis is critical for the survival and virulence of fungal pathogens. Cu homeostasis has been extensively studied in mammals, bacteria, and yeast, but it has not yet been well documented in filamentous fungi. In the present work, we investigated Cu tolerance in the filamentous fungus Fusarium oxysporum by analysing the Cu transporter coding gene crpF, previously studied in Aspergillus fumigatus. The expression studies demonstrated that crpF is upregulated in the presence of Cu and its deletion leads to severe sensitivity to low levels of CuSO4 in F. oxysporum. Targeted deletion of crpF did not significantly alter the resistance of the fungus to macrophage killing, nor its pathogenic behaviour on the tomato plants. However, the targeted deletion mutant ΔcrpF showed increased virulence in a murine model of systemic infection compared to wild-type strain (wt).

A comparative assessment of the performance of fungal-bacterial and fungal biofilters for methane abatement

Methane is an important contributor to global warming and especially for dilute emissions, its oxidation to carbon dioxide can be difficult and expensive. Methane abatement was studied in a biofilter inoculated solely with the filamentous fungus Fusarium solani and compared to a biofilter inoculated with a consortium of methanotrophic bacteria (Methylomicrobium album and Methylocystis sp.) and F. solani.Results showed that F. solani degrade methane as the sole carbon source, achieving a maximum elimination capacity of 42.2 g m−3 h-1, nearly half of the maximum elimination capacity of the fungal-bacterial consortium. The second Damköhler number indicates that under the prevailing operational conditions, the fungal biofilter performance was bioreaction limited meanwhile external mass transport limitation was found on the fungal/methanotrophic bacteria biofilter.Results support the hypothesis that the beneficial effect of F. solani during CH4 biofiltration is mediated by biomass hydrophobicity rather than by an increase in the mass transfer area.

Identification and distribution of gene clusters required for synthesis of sphingolipid metabolism inhibitors in diverse species of the filamentous fungus Fusarium

BackgroundSphingolipids are structural components and signaling molecules in eukaryotic membranes, and many organisms produce compounds that inhibit sphingolipid metabolism. Some of the inhibitors are structurally similar to the sphingolipid biosynthetic intermediate sphinganine and are referred to as sphinganine-analog metabolites (SAMs). The mycotoxins fumonisins, which are frequent contaminants in maize, are one family of SAMs. Due to food and feed safety concerns, fumonisin biosynthesis has been investigated extensively, including characterization of the fumonisin biosynthetic gene cluster in the agriculturally important fungi Aspergillus and Fusarium. Production of several other SAMs has also been reported in fungi, but there is almost no information on their biosynthesis. There is also little information on how widely SAM production occurs in fungi or on the extent of structural variation of fungal SAMs.ResultsUsing fumonisin biosynthesis as a model, we predicted that SAM biosynthetic gene clusters in fungi should include a polyketide synthase (PKS), an aminotransferase and a dehydrogenase gene. Surveys of genome sequences identified five putative clusters with this three-gene combination in 92 of 186 Fusarium species examined. Collectively, the putative SAM clusters were distributed widely but discontinuously among the species. We propose that the SAM5 cluster confers production of a previously reported Fusarium SAM, 2-amino-14,16-dimethyloctadecan-3-ol (AOD), based on the occurrence of AOD production only in species with the cluster and on deletion analysis of the SAM5 cluster PKS gene. We also identified SAM clusters in 24 species of other fungal genera, and propose that one of the clusters confers production of sphingofungin, a previously reported Aspergillus SAM.ConclusionOur results provide a genomics approach to identify novel SAM biosynthetic gene clusters in fungi, which should in turn contribute to identification of novel SAMs with applications in medicine and other fields. Information about novel SAMs could also provide insights into the role of SAMs in the ecology of fungi. Such insights have potential to contribute to strategies to reduce fumonisin contamination in crops and to control crop diseases caused by SAM-producing fungi.

Ste2 receptor-mediated chemotropism of Fusarium graminearum contributes to its pathogenicity against wheat

Fusarium Head Blight of wheat, caused by the filamentous fungus Fusarium graminearum, leads to devastating global food shortages and economic losses. While many studies have addressed the responses of both wheat and F. graminearum during their interaction, the possibility of fungal chemotropic sensing enabling pathogenicity remains unexplored. Based on recent findings linking the pheromone-sensing G-protein-coupled receptor Ste2 to host-directed chemotropism in Fusarium oxysporum, we investigated the role of the Ste2 receptor and its downstream signaling pathways in mediating chemotropism of F. graminearum. Interestingly, a chemotropic response of growing hyphae towards catalytically active Triticum aestivum ‘Roblin’ cultivar secreted peroxidases was detected, with deletion of STE2 in F. graminearum leading to loss of the observed response. At the same time, deletion of STE2 significantly decreased infection on germinating wheat coleoptiles, highlighting an association between Ste2, chemotropism and infection by F. graminearum. Further characterization revealed that the peroxidase-directed chemotropism is associated with stimulation of the fungal cell wall integrity mitogen-activated protein kinase signaling cascade. Altogether, this study demonstrates conservation of Ste2-mediated chemotropism by Fusarium species, and its important role in mediating pathogenicity.

Biosynthetic gene cluster identification and biological activity of lucilactaene from Fusarium sp. RK97-94.

We identified the biosynthetic gene cluster for lucilactaene, a cell cycle inhibitor from a filamentous fungus Fusarium sp. RK 97-94. The luc1 knockout strain accumulated demethylated analogs, indicating the involvement of Luc1 methyltransferase in lucilactaene biosynthesis. Lucilactaene showed potent antimalarial activity. Our data suggested that methylation and ether ring formation are essential for its potent antimalarial activity.

The interaction of α-amylase with mycoprotein: Diffusion through the fungal cell wall, enzyme entrapment, and potential physiological implications

This study investigated the in vitro interaction of α-amylase with mycoprotein and the subsequent impact on carbohydrate digestion. Mycoprotein is a food ingredient obtained from the fermentation of the filamentous fungus Fusarium venenatum, whose hyphal structure is determined by cell walls mainly composed of β-glucans and chitin. Simulated digestion showed that α-amylase hydrolysed the intracellular glycogen from within the mycoprotein hyphae, as shown by the increase in concentration of reducing sugars (glycogen amylolysis products) in the digestion fluid over time. The presence of fungal cell walls slowed down the kinetics of reducing sugar release during digestion when compared to extracted glycogen (no cell walls). The enzyme was able to diffuse through the fungal cell walls as evident from confocal-laser-scanning-microscopy which showed the presence of FITC-labelled α-amylase inside the cells, and the reduction of the free enzyme concentration in the surrounding solution. Consequently, in vitro digestion of starch in the presence of increasing concentrations of mycoprotein showed a reduced starch hydrolysis rate by α-amylase. Starch hydrolysis after 12 min of in vitro digestion was decreased from a value of 18.19 wt% without mycoprotein to 4.47 wt% (***p-value < 0.001) in the presence of the highest mycoprotein concentration. Kinetic analyses of starch digestion by amylase in the presence of different concentrations of mycoprotein revealed a linear reversible mixed inhibition. These findings are relevant to understanding the mechanisms by which mycoprotein has been observed to attenuate postprandial glycaemia/insulinemia and may have potential applications in food industry processes that aim to reduce/limit starch hydrolysis.