Azole resistance in Aspergillus is one of the emerging public health concerns, listed as a WHO priority and suited to an integrated One Health approach. Selective pressure due to the use of azole pesticides in agriculture being incriminated, identification of clinical and environmental resistance patterns, and a greater understanding of the factors driving this resistance are urgently needed in order to issue recommendations to the stakeholders. The multidisciplinary AspergillusOne-health project strengthened with model and innovative methodologies (WGS, genotyping, MALDI typing, metabarcoding, AI) aims to identify hotspots as possible sources for selection of azole-resistance in the environment, after the detection of azole-resistant Aspergillus in patients and patiens's home, avian facilities, the environment (farming and sawmills), and detection of the azole fungicides in soil and air. The role of resistance trait on Aspergillus fitness cost will be investigated, using environmental strains and mutants selected after fungicide pressure, to assess its clinical involvement.

Most land plants live symbiotically with microscopic soil fungi of the order Glomeromycota. This very ancient interaction, called the Arbuscular mycorrhizal (AM) symbiosis, is observed across a wide range of ecosystems and is on a global scale a major player in plant nutrition, soil structure and carbon cycling. AM fungi bear great potential for biofertilization as an alternative to chemical inputs. They develop both within cortical root cells and into the soil, forming a sort of extension of the root system. In host roots the fungi differentiate into specialized structures called arbuscules, where nutrient exchanges take place: the fungus provides its host plant with otherwise inaccessible mineral nutrients, in exchange for organic carbon. In addition, AM fungi and their hosts control each other's development. Furthermore, plants connected by a Common Mycorrhizal Network (CMN) can exchange via the fungus information related to pathogen or herbivore attack. The symbiosis is controlled through extensive molecular communication between the two partners. The project aims to investigate the role of phytohormones in this communication. Several lines of evidence suggest that the fungal partner could also be a source and target of phytohormone signalling. In particular, we identified in AM fungal genomes homologs of plant cytokinin and ethylene receptors, and detected hormones released by isolated AM fungi. With this project, we will investigate for the first time on a large scale whether AM fungi are themselves able to produce and transport phytohormones, whether they use them as internal regulators and whether they can convey information between plants by transporting hormones in CMNs. To reach these goals, the project brings together two academic groups and an industrial partner specialized in the production of biofertilizers. We will implement mass spectrometry techniques to detect hormones released in vitro by isolated AM fungi. This will be greatly facilitated by the industrial partner, who will provide large amounts of AM biological material. For the hormones we can detect, we will try to determine whether the fungi performed their biosynthesis or released previously accumulated hormones of plant origin. We will examine the biological effects that exogenously applied phytohormones can have on AM fungi, and try to decipher the underlying cellular and molecular mechanisms. We will also analyse the perception of cytokinins, ethylene and strigolactones, for which we have identified candidate receptors. Finally, we will use labelled phytohormones or analogs to examine their bidirectional transport between host plants and AM fungi, and between plants connected by a CMN. Since the "normal" situation of plants is to live interaction with AM fungi, our findings will unravel how plant development and physiology are shaped in natural environments. Our project will also yield new knowledge to favour the use of AM fungi as biofertilizers, in line with the current demand for more sustainable agricultural practices.