AoSte12 is required for mycelial development, conidiation, trap morphogenesis, and secondary metabolism by regulating hyphal fusion in nematode-trapping fungus of Arthrobotrys oligospora [DAP-seq]
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ABSTRACT:
ORGANISM(S): Orbilia oligospora
PROVIDER: GSE213449 | GEO | 2023/01/29
REPOSITORIES: GEO
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Project description:Nematode-trapping (NT) fungi are a unique group of carnivorous microorganisms that can capture and digest nematodes by producing ingenious trapping devices (traps). Arthrobotrys oligospora, a representative NT fungus, can develop adhesive three-dimensional networks for nematode predation. Hyphal fusion is indispensable for the trap formation of A. oligospora. Here, we characterized an orthologous Ste12 protein (AoSte12) in A. oligospora via gene disruption, DNA affinity purification sequencing (DAP-Seq), and multi-omics approaches. The disruption of the Aoste12 gene caused an increase in hyphal fusion and resulted in defects in mycelial growth, conidiation, trap morphology, and stress resistance, as well as reducing the number of nuclei and lipid droplet accumulation. Moreover, transcriptome and DAP-Seq analysis revealed that AoSte12 was involved in cellular processes associated with growth, cell fusion, the tricarboxylic acid cycle, vesicles, actin filaments, and lipid metabolism. In addition, combining metabolome with transcriptome and DAP-Seq analysis indicated that AoSte12 was involved in the mitogen-activated protein kinase signaling pathway, lipid metabolism, and secondary metabolites. A yeast two-hybrid assay revealed that AoSte12 can interact with diverse proteins, such as the MAK-2 orthologue protein Fus3, the vacuolar sorting protein Pep3, and UDP-glycosyltransferase. Our results suggest that AoSte12 plays an indispensable role in hyphal fusion and thus regulates sporulation and trap morphogenesis. These results provide deep insights into the connection between hyphal fusion and trap formation in NT fungi. IMPORTANCE Nematode-trapping (NT) fungi are an important natural enemy of nematodes and can capture their prey by producing traps. Hyphal anastomosis and fusion are important for mycelial growth and the colony morphological development of filamentous fungi and are also crucial for the trap morphogenesis of NT fungi. Arthrobotrys oligospora can form complex three-dimensional networks (traps) when sensing the presence of nematodes. This study revealed that AoSte12 is indispensable for hyphal fusion and that it regulates mycelial growth, conidiation, trap morphogenesis, stress resistance, the number of nuclei, and lipid droplet accumulation in A. oligospora. In addition, DNA affinity purification sequencing, transcriptome, and metabolome analyses further revealed that AoSte12 is involved in the mitogen-activated protein kinase pathway, lipid metabolism, and secondary metabolism. Overall, these findings expand the important role of AoSte12 in NT fungus A. oligospora and provide a broad foundation for elucidating the regulatory mechanism of trap development and the lifestyle transitions of pathogenic fungi.
| S-EPMC10101105 | biostudies-literature
Project description:Inducer of meiosis 2 (Ime2), a protein kinase that has been identified in diverse fungal species, functions in the regulation of various cellular processes, such as ascospore formation, pseudohyphal growth, and sexual reproduction. In this study, AoIme2, an ortholog of Saccharomyces cerevisiae Ime2, was characterized in the nematode-trapping fungus Arthrobotrys oligospora. Disruption of the gene Aoime2 caused defective growth, with slower mycelial growth in ΔAoime2 mutants than the wild type (WT) strain, and in the mutants, the number of hyphal septa in mycelia was higher and the number of cell nuclei in mycelia and conidia was considerably lower than in the WT strain. The conidial yields of the ΔAoime2 mutants were decreased by ∼33% relative to the WT strain, and the transcription of several sporulation-related genes, including abaA, fluG, rodA, aspB, velB, and vosA, was markedly downregulated during the conidiation stage. The ΔAoime2 mutants were highly sensitive to the osmotic stressors NaCl and sorbitol, and the cell wall of partial hyphae in the mutants was deformed. Further examination revealed that the cell wall of the traps produced by ΔAoime2 mutants became loose, and that the electron-dense bodies in trap cells were also few than in the WT strain. Moreover, Aoime2 disruption caused a reduction in trap formation and serine-protease production, and most hyphal traps produced by ΔAoime2 mutants did not form an intact hyphal loop; consequently, substantially fewer nematodes were captured by the mutants than by the WT strain. In summary, an Ime2-MAPK is identified here for the first time from a nematode-trapping fungus, and the kinase is shown to be involved in the regulation of mycelial growth and development, conidiation, osmolarity, and pathogenicity in A. oligospora.
| S-EPMC6971104 | biostudies-literature
Project description:Transcriptomic analysis revealed that differentially expressed genes in the absence of AoSte12 were involved in mycelial growth, development process,conidiation, cell nucleus and trap formation.
2023-01-29 | GSE213447 | GEO
Project description:Hog1, a mitogen-activated protein kinase (MAPK), has been identified in diverse fungal species, and it regulates various cellular processes, such as osmoadaptation, nutrient-sensing, and pathogenesis. However, the roles that Hog1 plays in nematode-trapping fungi were previously unclear. Here, we characterized orthologs of Saccharomyces cerevisiae Hog1 and membrane mucin Msb2 in the nematode-trapping fungus Arthrobotrys oligospora. We generated gene deletion mutants of HOG1 and MSB2 in A. oligospora, and characterized their roles in osmosensing, growth, and trap morphogenesis. We found that both hog1 and msb2 mutants were highly sensitive to high osmolarity. Predation analyses further revealed that hog1 and msb2 deletion caused a reduction in trap formation and predation efficiency. Furthermore, HOG1 is required for conidiation in A. oligospora, demonstrating its critical role in this developmental pathway. In summary, this study demonstrated that the conserved Hog1 and Msb2 govern physiology, growth and development in the nematode-trapping fungus A. oligospora.
| S-EPMC7711997 | biostudies-literature
Project description:Malate dehydrogenase (MDH) is a key enzyme in the tricarboxylic acid (TCA) cycle and is essential for energy balance, growth, and tolerance to cold and salt stresses in plants. However, the role of MDH in filamentous fungi is still largely unknown. In this study, we characterized an ortholog of MDH (AoMae1) in a representative nematode-trapping (NT) fungus Arthrobotrys oligospora via gene disruption, phenotypic analysis, and nontargeted metabolomics. We found that the loss of Aomae1 led to a weakening of MDH activity and ATP content, a remarkable decrease in conidia yield, and a considerable increase in the number of traps and mycelial loops. In addition, the absence of Aomae1 also caused an obvious reduction in the number of septa and nuclei. In particular, AoMae1 regulates hyphal fusion under low nutrient conditions but not in nutrient-rich conditions, and the volumes and sizes of the lipid droplets dynamically changed during trap formation and nematode predation. AoMae1 is also involved in the regulation of secondary metabolites such as arthrobotrisins. These results suggest that Aomae1 has an important role in hyphal fusion, sporulation, energy production, trap formation, and pathogenicity in A. oligospora. Our results enhance the understanding of the crucial role that enzymes involved in the TCA cycle play in the growth, development, and pathogenicity of NT fungi.
| S-EPMC10146936 | biostudies-literature
Project description:Arthrobotrys oligospora is a typical nematode-trapping fungus capturing free-living nematodes by adhesive networks. Component of the low-affinity calcium uptake system (LACS) has been documented to involve in growth and sexual development of filamentous fungi. Bioassay showed incapacity of trap formation in A. oligospora on Water Agar plate containing 1 mM ethylene glycol tetraacetic acid (EGTA) due to Ca2+ absorbing block. The functions of homologous proteins (AoFIG_1 and AoFIG_2) of LACS were examined on conidiation and trap formation of A. oligospora. Compared with wild type, ΔAoFIG_1 (AOL_s00007g566) resulted in 90% of trap reduction, while ΔAoFIG_2 (AOL_s00004g576) reduced vegetative growth rate up to 44% and had no trap and conidia formed. The results suggest that LACS transmembrane protein fig1 homologs play vital roles in the trap-formation and is involved in conidiation and mycelium growth of A. oligospora. Our findings expand fig1 role to include development of complex trap device and conidiation.
| S-EPMC6418195 | biostudies-literature
Project description:The velvet family proteins VosA and VelB are involved in growth regulation and differentiation in the model fungus Aspergillus nidulans and other filamentous fungi. In this study, the orthologs of VosA and VelB, AoVosA, and AoVelB, respectively, were characterized in the nematode-trapping fungus Arthrobotrys oligospora, which captures nematodes by producing trapping devices (traps). Deletion of the AovelB gene resulted in growth defects in different media, and the aerial hyphae from the ΔAovelB mutant lines were fewer in number and their colonies were less dense than those from the wild-type (WT) strain. The ΔAovelB mutants each displayed serious sporulation defects, and the transcripts of several sporulation-related genes (e.g., abaA, flbC, rodA, and vosA) were significantly down-regulated compared to those from the WT strain. Furthermore, the ΔAovelB mutant strains became more sensitive to chemical reagents, including sodium dodecyl sulfate and H2O2. Importantly, the ΔAovelB mutants were unable to produce nematode-capturing traps. Similarly, extracellular proteolytic activity was also lower in the ΔAovelB mutants than in the WT strain. In contrast, the ΔAovosA mutants displayed no obvious differences from the WT strain in these phenotypic traits, whereas conidial germination was lower in the ΔAovosA mutants, which became more sensitive to heat shock stress. Our results demonstrate that the velvet protein AoVelB is essential for conidiation, trap formation, and pathogenicity in A. oligospora, while AoVosA plays a role in the regulation of conidial germination and heat shock stress.
| S-EPMC6710351 | biostudies-literature
Project description:ADP-ribosylation factors (Arfs) belong to the small GTPases superfamily and regulate mycelial development, endocytosis, and virulence in fungi. Nematode-trapping (NT) fungi can form unique infection structures (traps) to capture and kill free-living nematodes, thus play a potential role in the biocontrol of nematodes. Arthrobotrys oligospora is a representative species of the NT fungi. Here, the functions of two Arf-GAPs, Age1 (AoAge1) and Age2 (AoAge2) orthologue to S. cerevisiae were identified in A. oligospora by gene knockout and multi-phenotypic analysis. It was found that AoAge1 and AoAge2, especially AoAge2, play an important role in vegetative growth, conidiation, trap formation, DNA damage, endoplasmic reticulum stress, mitochondrial activity, endocytosis, heat shock stress, ROS level, and autophagy of A. oligospora. Importantly, our transcriptomic analysis (12 h) showed that nearly 62.7% of A. oligospora genes (11479) were directly or indirectly regulated by AoAge2, indicating that Arf-GAP plays a global role in the growth and development of A. oli gospora. Revealed by transcriptomic analysis differentially upregulated genes in the absence of Aoage2 were involved in autophagy and carbohydrate, amino acid and sphingolipid metabolism while downregulated genes were involved in longevity regulating pathway and carbohydrate, amino acid and secondary metabolites biosynthesis. In addition, metabolomic analysis showed that many compounds were markedly reduction in ΔAoage2 mutants strain. Our results highlighted that AoAge1 and AoAge2 play a crucial role in the asexual growth, development, differentiation, and lifestyle transition, especially, AoAge2 is indispensable for conidiation and trap morphogenesis of A. oligospora. These results demonstrated crucial roles for AoAge1 and AoAge2 in the fungal growth, environmental adaption and pathogenicity, which provided insights into the function of Arf-GAPs in A. oligospora and other fungi.
2024-01-26 | GSE253759 | GEO
Project description:Mitogen-activated protein kinase (MAPK) Fus3 is an essential regulator of cell differentiation and virulence in fungal pathogens of plants and animals. However, the function and regulatory mechanism of MAPK signaling in nematode-trapping (NT) fungi remain largely unknown. NT fungi can specialize in the formation of "traps", an important indicator of transition from a saprophytic to a predatory lifestyle. Here, we characterized an orthologous Fus3 in a typical NT fungus Arthrobotrys oligospora using multi-phenotypic analysis and multi-omics approaches. Our results showed that Fus3 plays an important role in asexual growth and development, conidiation, stress response, DNA damage, autophagy, and secondary metabolism. Importantly, Fus3 plays an indispensable role in hyphal fusion, trap morphogenesis, and nematode predation. Moreover, we constructed the regulatory networks of Fus3 by means of transcriptomic and yeast two-hybrid techniques. This study provides insights into the mechanism of MAPK signaling in asexual development and pathogenicity of NT fungi.
| S-EPMC10440713 | biostudies-literature
Project description:Nematode-trapping fungi (NTF) are carnivorous fungi that prey on nematodes under nutrient-poor conditions via specialized hyphae that function as traps. The molecular mechanisms involved in the interactions between NTF and their nematode prey are largely unknown. In this study, we conducted forward genetic screens to identify potential genes and pathways that are involved in trap morphogenesis and predation in the NTF Arthrobotrys oligospora. Using Ethyl methanesulfonate and UV as the mutagens, we generated 5552 randomly mutagenized A. oligospora strains and identified 15 mutants with strong defects in trap morphogenesis. Whole-genome sequencing and bioinformatic analyses revealed mutations in genes with roles in signaling, transcription or membrane transport that may contribute to the defects of trap morphogenesis in these mutants. We further conducted functional analyses on a candidate gene, YBP-1, and demonstrate that mutation of that gene was causative of the phenotypes observed in one of the mutants. The methods established in this study might provide helpful insights for establishing forward genetic screening methods for other non-model fungal species.
| S-EPMC8022932 | biostudies-literature