Project description:The fungal specific APSES family proteins involve in regulating fungal growth, development, and multiple biological processes. In this study, AoMbp1, an ortholog of Saccharomyces cerevisiae APSES-type transcription factor Mbp1, was functionally analyzed in a representative nematode-trapping fungus Arthrobotrys oligospora. Inactivation of Aombp1 caused a severe affect on the mycelial growth and development, the mycelial growth rate of ∆Aombp1 mutant was remarkably decreased, the hyphal septa were increased whereas the number of nuclei were significantly reduced, and the lipid droplet accumulation was remarkably increased. Meanwhile, the deletion of Aombp1 resulted a considerable reduction in the number of conidiophores and spore yield, which also caused abnormal spore morphology. In addition, the ∆Aombp1 mutants became more sensitive to several chemical stressors, especially to hyperosmotic reagents. Importantly, disruption of Aombp1 caused the number of traps and nematode-trapping ability were significantly reduced, and most of the traps have changed from their original three-dimensional structure to a planar shape. RNA-Seq, DAP-Seq and Y2H assay showed that AoMbp1 interacted with AoSwi6, and involved in regulating cell cycle, meiosis, lipid metabolism, DNA replication, mismatch repair and nucleotide excision repair. Our study elucidated the functions and potential regulatory mechanism of APSES protein Mbp1 in the mycelial development and trap morphogenesis of nematode-trapping fungi.
Project description:Arthrobotrys oligospora, a widely distributed nematode-trapping fungus, utilises adhesive mycelial nets (traps) to capture nematodes. As key components of the MAPK cascade, Sho1 and Opy2 are critical in the fungal stress response. This study examined the roles of homologous Sho1 (AoSho1) and Opy2 (AoOpy2) through gene knockdown, phenotypic analysis, and multi-omics approaches. The results revealed that knockdown of Aosho1 and Aoopy2 led to reduced mycelial growth, a significant decrease in spore production, trap formation, and nematode predation capacity. Furthermore, deletion of Aosho1 and Aoopy2 increased autophagic activity and heightened sensitivity to osmotic stress. Transcriptome analysis indicated that AoOpy2 functions as a multifaceted regulator in fungal growth, development, and environmental adaptation. Metabolomics data also suggested that AoSho1 and AoOpy2 are involved in several metabolic pathways. In conclusion, AoSho1 and AoOpy2 are essential for mycelial growth, osmoregulation, and the pathogenicity of A. oligospora. This study lays the groundwork for understanding the roles and potential mechanisms of the MAPK signalling pathway in the development and pathogenicity of nematode-trapping fungi.
Project description:Rab GTPases regulate vesicle trafficking in organisms and play crucial roles in growth and development. Arthrobotrys oligospora is a representative species of nematode-trapping (NT) fungi, it can produce trapping devices for nematode predation. Our previous study found that deletion of Aorab7A abolished the trap formation and sporulation. Here, we investigated the regulatory mechanism of AoRab7A using transcriptomic, biochemical, and phenotypic comparisons. Transcriptome analysis, yeast library screening, and Y2H assays identified two vacuolar protein sorting (Vps) proteins, AoVps41 and AoVps35, as putative targets of AoRab7A. The deletion of Aovps41 and Aovps35 caused considerable defects in multiple phenotypic traits. We further found a close connection between AoRab7A, homotypic fusion, vacuolar protein sorting, and the retromer involved in vesicle-vacuole fusion, which triggered vacuolar fragmentation. Further transcriptome analysis showed that AoRab7A and AoVps35 play essential roles in many cellular processes and components including proteasomes, autophagy, fatty acid degradation, and ribosomes in A. oligospora. Furthermore, we verified that AoRab7A, AoVps41, and AoVps35 are involved in ribosome and proteasome functions. The absence of these proteins inhibited the biosynthesis of nascent proteins and enhanced ubiquitination. Our findings suggest that AoRab7A can interact with AoVps41 and AoVps35 to mediate vacuolar fusion and influence lipid droplet accumulation, autophagy, stress response, and secondary metabolism. These proteins are especially required for the conidiation and trap development of A. oligospora
Project description:We report the transcriptomic comparisions between key processes required for various stages of fungal carnivory in nematode-trapping fungus Arthrobotrys oligospora when induced with nematodes. The reference assembly used for remapping is A. oligospora TWF154 (GenBank assembly accession: GCA_004768765.1)
Project description:Arthrobotrys flagrans, a typical nematode-trapping fungus (NTF) that produces a three-dimensional adhesive network to capture nematodes, has excellent potential for the de-velopment of biocontrol agents against both plant and animal parasitic nematodes. Proteins containing the common fungal extracellular membrane (CFEM) domain are important for the nematodes' trapping by A. flagrans. The loss of AfCFEM1 and AfCFEM3 resulted in a significant upregulation of proteins associated with fungal pathogenicity, forming a denser adhesive material on the trap surface and ultimately increasing nematode mortality. However, the disruption of AfCFEM2 led to the opposite result. Furthermore, the deletion of AfCFEM1-3 not only affected trap morphology, resulting in an increased proportion of irregular traps (i.e., trap cells not fused to the hyphae), but also led to a thinner cell wall of the traps. Besides, the compensate effects among the CFEM family and other families were demonstrated. This study revealed that the AfCFEM1-3 genes in A. flagrans participated in nematode adhesion, cell wall formation, and intercellular communication, providing new insights into the functions of AfCFEM in the process of nematode trapping by NTF.
Project description:We report the transcriptomic comparisions between ku70 control and ste12 mutant strains in nematode-trapping fungus Arthrobotrys oligospora when induced with nematodes. Fungal Ste12 transcription factor and the upstream MAPK cascade are highly conserved and plays a role in host sensing and pathogenesis in various fungal pathogens. Identification of Ste12-dependent in A. oligospora may provide further insights into the molecular mechanisms of nematode-sensing and trap morphogenesis. The reference assemly used for remapping is A. oligospora TWF154 (GenBank assembly accession: GCA_004768765.1)
Project description: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 we performed dual RNA-seq to understand the interaction between A. oligospora and Caenorhabditis elegans. We identified 5752 unique differentially expressed genes during trap formation and predation, and the rac gene was significantly upregulated. Alternative splicing events occurred in 896 2012 genes, including the rac and rho2 gene. Further, we characterized three Rho GTPases (Rho2, Rac, and Cdc42) in A. oligospora using gene disruption and multi-phenotypic analysis. The analyses showed that AoRac and AoCdc42 play an important role in mycelium growth, lipid accumulation, DNA damage, sporulation, trap formation, pathogenicity, and stress response in A. oligospora. Furthermore, AoCdc42 and AoRac specifically interacted with components of the Nox complex, thus regulating the production of reactive oxygen species. Furthermore, the transcript levels of several genes associated with the protein kinase A, mitogen-activated protein kinase, and p21-activated kinase were also altered in the mutants, suggesting that Rho GTPases might function upstream of these kinases. This study highlights the important role of Rho GTPases in A. oligospora and provides insights into the regulatory mechanism of signaling pathways in trap morphogenesis and lifestyle transition of NT fungi.