The role of copper homeostasis in the application of the nematode-trapping fungus Arthrobotrys flagrans as a plant growth promoter and biocontrol agent against plant-parasitic nematodes.

• Applicant: Dr. Rafael Palos Fernández
• Subject Area: Plant Breeding and Plant Pathology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569796675

Nematodes are the most common animals on earth and many of them live parasitically on plants, posing a major threat to our crops. It is estimated that nematode infestations cause more than US$150 billion in damage to agriculture every year. Strategies to control nematodes include crop rotation and the use of resistant lines. Both strategies have only limited value because, for example, crop rotation is impossible in the case of wine and the resistance of cultivars only offers temporary protection. One solution could be the use of nematode-trapping fungi (NTF). These fungi are ubiquitous and switch from saprotrophic growth to a predatory lifestyle when nutrients are lacking and nematodes are present. Arthrobotrys flagrans is an NTF with application potential because this fungus produces resistant chlamydospores that can serve as inoculum for soil inoculation. There was evidence and new results in the guest lab show that A. flagrans is able to colonize plant roots endophytically and capture nematodes during the interaction with the plant. The interaction of A. flagrans with the plant even promotes plant growth. Copper-related genes have also been found to be upregulated during plant colonization and trapping; in particular, a novel gene cluster (ctrC gene cluster) comprising a copper transporter and two LPMO (lytic polysaccharide monooxigenases) genes homologous to genes involved in virulence of the animal pathogen Cryptococcus neoformans is induced during trapping and growth in plants in A. flagrans. Therefore, this proposal focuses on understanding at the molecular level how A. flagrans forms traps, colonizes plant roots and, in particular, how copper homeostasis influences these processes. To this end, the role of the transcription factor MacA, the most important regulator of copper homeostasis in fungi, and the ctrC gene cluster in the regulation of copper uptake will be investigated. The two-year work program includes transcriptional analyses, gene deletion studies, microscopy analyses and phenotypic tests under different copper conditions. Ultimately, the project aims to optimize the use of A. flagrans in agriculture by better understanding the dual role of A. flagrans in nematode control and plant growth promotion in order to develop future strategies to improve nematode control.

• DFG Programme: WBP Position