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Hyphal growth of phagocytosed Fusarium oxysporum causes cell lysis and death of murine macrophages.

ABSTRACT: Fusarium oxysporum is an important plant pathogen and an opportunistic pathogen of humans. Here we investigated phagocytosis of F. oxysporum by J774.1 murine cell line macrophages using live cell video microscopy. Macrophages avidly migrated towards F. oxysporum germlings and were rapidly engulfed after cell-cell contact was established. F. oxysporum germlings continued hyphal growth after engulfment by macrophages, leading to associated macrophage lysis and escape. Macrophage killing depended on the multiplicity of infection. After engulfment, F. oxysporum inhibited macrophages from completing mitosis, resulting in large daughter cells fused together by means of a F. oxysporum hypha. These results shed new light on the initial stages of Fusarium infection and the innate immune response of the mammalian host.

SUBMITTER: Schafer K

PROVIDER: S-EPMC4099067 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Hyphal growth of phagocytosed Fusarium oxysporum causes cell lysis and death of murine macrophages.

Schäfer Katja K Bain Judith M JM Di Pietro Antonio A Gow Neil A R NA Erwig Lars P LP

PloS one 20140715 7

Fusarium oxysporum is an important plant pathogen and an opportunistic pathogen of humans. Here we investigated phagocytosis of F. oxysporum by J774.1 murine cell line macrophages using live cell video microscopy. Macrophages avidly migrated towards F. oxysporum germlings and were rapidly engulfed after cell-cell contact was established. F. oxysporum germlings continued hyphal growth after engulfment by macrophages, leading to associated macrophage lysis and escape. Macrophage killing depended o ...[more]

PMID: 25025395

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Target of rapamycin controls hyphal growth and pathogenicity through FoTIP4 in Fusarium oxysporum.

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Autophagy contributes to regulation of nuclear dynamics during vegetative growth and hyphal fusion in Fusarium oxysporum.

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| S-EPMC2762075 | biostudies-literature

Fusarium Oxysporum Volatiles Enhance Plant Growth Via Affecting Auxin Transport and Signaling.

Project description:Volatile organic compounds (VOCs) have well-documented roles in plant-plant communication and directing animal behavior. In this study, we examine the less understood roles of VOCs in plant-fungal relationships. Phylogenetically and ecologically diverse strains of Fusarium oxysporum, a fungal species complex that often resides in the rhizosphere of assorted plants, produce volatile compounds that augment shoot and root growth of Arabidopsis thaliana and tobacco. Growth responses of A. thaliana hormone signaling mutants and expression patterns of a GUS reporter gene under the auxin-responsive DR5 promoter supported the involvement of auxin signaling in F. oxysporum volatile-mediated growth enhancement. In addition, 1-naphthylthalamic acid, an inhibitor of auxin efflux, negated F. oxysporum volatile-mediated growth enhancement in both plants. Comparison of the profiles of volatile compounds produced by F. oxysporum strains that differentially affected plant growth suggests that the relative compositions of both growth inhibitory and stimulatory compounds may determine the degree of plant growth enhancement. Volatile-mediated signaling between fungi and plants may represent a potentially conserved, yet mostly overlooked, mechanism underpinning plant-fungus interactions and fungal niche adaption.

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The FgHOG1 pathway regulates hyphal growth, stress responses, and plant infection in Fusarium graminearum.

Project description:Fusarium head blight (FHB) caused by Fusarium graminearum is a destructive disease of wheat and barley worldwide. In a previous study of systematic characterization of protein kinase genes in F. graminearum, mutants of three putative components of the osmoregulation MAP kinase pathway were found to have distinct colony morphology and hyphal growth defects on PDA plates. Because the osmoregulation pathway is not known to regulate aerial hyphal growth and branching, in this study we further characterized the functions of the FgHog1 pathway in growth, pathogenesis, and development. The Fghog1, Fgpbs2, and Fgssk2 mutants were all reduced in growth rate, aerial hyphal growth, and hyphal branching angle. These mutants were not only hypersensitive to osmotic stress but also had increased sensitivity to oxidative, cytoplasm membrane, and cell wall stresses. The activation of FgHog1 was blocked in the Fgpbs2 and Fgssk2 mutants, indicating the sequential activation of FgSsk2-FgPbs2-FgHog1 cascade. Interestingly, the FgHog1 MAPK pathway mutants appeared to be sensitive to certain compounds present in PDA. They were female sterile but retained male fertility. We also used the metabolomics profiling approach to identify compatible solutes that were accumulated in the wild type but not in the Fghog1 deletion mutant. Overall, our results indicate that the FgSsk2-FgPbs2-FgHog1 MAPK cascade is important for regulating hyphal growth, branching, plant infection, and hyperosmotic and general stress responses in F. graminearum.

| S-EPMC3498113 | biostudies-literature

Non-canonical Helitrons in Fusarium oxysporum.

Project description:BACKGROUND:Helitrons are eukaryotic rolling circle transposable elements that can have a large impact on host genomes due to their copy-number and their ability to capture and copy genes and regulatory elements. They occur widely in plants and animals, and have thus far been relatively little investigated in fungi. RESULTS:Here, we comprehensively survey Helitrons in several completely sequenced genomes representing the F. oxysporum species complex (FOSC). We thoroughly characterize 5 different Helitron subgroups and determine their impact on genome evolution and assembly in this species complex. FOSC Helitrons resemble members of the Helitron2 variant that includes Helentrons and DINEs. The fact that some Helitrons appeared to be still active in FOSC provided the opportunity to determine whether Helitrons occur as a circular intermediate in FOSC. We present experimental evidence suggesting that at least one Helitron subgroup occurs with joined ends, suggesting a circular intermediate. We extend our analyses to other Pezizomycotina and find that most fungal Helitrons we identified group phylogenetically with Helitron2 and probably have similar characteristics. CONCLUSIONS:FOSC genomes harbour non-canonical Helitrons that are characterized by asymmetric terminal inverted repeats, show hallmarks of recent activity and likely transpose via a circular intermediate. Bioinformatic analyses indicate that they are representative of a large reservoir of fungal Helitrons that thus far has not been characterized.

| S-EPMC5148889 | biostudies-literature

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