Elucidation of the role of non-ribosomal peptides and of a statin produced by the nematode-trapping fungus, Duddingtonia flagrans, during the interaction with Caenorhabditis elegans

• Applicant: Dr. Maria Cristina Stroe
• Subject Area: Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems ; Microbial Ecology and Applied Microbiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 497485743

The overall aim of this project is to obtain an overview of the evolution and function of secondary metabolites in nematode trapping-fungi. This will be achieved by (i) characterizing the unexplored biosynthetic genes of D. flagrans during the interaction of D. flagrans with C. elegans, and by (ii) revealing the role of a D. flagrans-produced statin during predation of the nematode. Excitingly, since nematode-trapping fungi like D. flagrans have two lifestyles, saprotroph and predatory, we can expect that the data obtained during this project will generate new transferable knowledge about both nematicidal and antimicrobial drugs.The first objective is to functionally characterize the D. flagrans non-ribosomal peptide synthetases identified through bioinformatic analysis. Most putative biosynthesis genes are hardly expressed in D. flagrans. To ensure a rapid isolation of the compounds, the cryptic genes or gene clusters will first be expressed in A. nidulans. The second objective is to identify and purify the resulting secondary metabolites. Therefore, the A. nidulans transformant strains now containing the D. flagrans genes of interest will be cultured, extracted using chemical solvents and analyzed using HPLC and MS. Furthermore, as a drug discovery aspect, the identified compounds will be subjected to extensive bioactivity testing.The third objective is to identify the ecological role of the D. flagrans secondary metabolites. For this purpose, the expression of the candidate D. flagrans genes will be determined using fluorescence reporter strains. Transformant D. flagrans strains will be generated and challenged with C. elegans. The final objective is to decipher the role of the statin compound which is produced by D. flagrans in the hyphal traps formed to kill C. elegans. This will be achieved using C. elegans reporter strains, transcriptomic analysis and a bead assay with immobilized statin. The identified protein targets will be deleted and the susceptibility of the resulting C. elegans strains towards the fungus will be assessed.

• DFG Programme: WBP Position