Metal nanoparticles: phytotoxicity on tomato and effect on symbiosis with the Fusarium solani FsK strainMetal nanoparticles: phytotoxicity on tomato and effect on symbiosis with the Fusarium solani FsK strain Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2022-11-292021enThis study was co-financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH–CREATE - INNOVATE (project code: Τ2EDK-00597). MA is supported by the European Union (European Social Fund - ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning” in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (ІΚΥ).The effect of copper (Cu-NPs, CuO-NPs), silver (Ag-NPs) and zinc oxide (ZnO-NPs) nanoparticles (NPs) on plant growth, physiological properties of tomato plants and their symbiotic relationships with the endophytic Fusarium solani FsK strain was investigated. Fungitoxicity tests revealed that the FsK strain was significantly more sensitive to Cu-NPs and ZnO-NPs than CuO-NPs and Ag-NPs both in terms of mycelial growth and spore germination. All NPs were more toxic to FsK compared to their bulk counterparts except for AgNO3, which was 8 to 9-fold more toxic than Ag-NPs. Apart from AgNO3, NPs and bulk counterparts did not affect the number of germinated tomato seeds even in higher concentrations, while root length was significantly reduced in a dose dependent way in most cases. Dry weight of tomato plants was also significantly reduced upon treatment with NPs and counterparts with most pronounced effects in the cases of AgNO3, Cu-NPs, ZnO-NPs, and ZnSO4. Root and shoot length of grown tomato plants was also affected by treatments while differences between NPs and bulk counterparts varied. A marked oxidative stress response was recorded in all cases of NPs/bulk counterparts as indicated by increased MDA and H2O2 levels of treated plants. Treated plants had significantly reduced chlorophyl-a and carotenoid levels compared to the untreated control. NPs and counterparts did not affect FsK colonization of roots indicating a possible shielding effect of tomato plants once the endophyte was established inside the roots. Vice versa, a possible alleviation of CuO-NPs, ZnO-NPs, and ZnSO4 toxicity was observed in the presence of FsK inside tomato roots in terms of plant dry weight. The results suggest that phytotoxicity of NPs in tomato treated plants should be considered before application and while both FsK and tomato are sensitive to NPs, their reciprocal benefits may extent to resistance towards these toxic agents.http://creativecommons.org/licenses/by/4.0/Science of the Total Environment787 Malandrakis Anastasios Μαλανδρακης Αναστασιος Kavroulakis Nektarios Avramidou Marianna Papadopoulou Kalliope K. Tsaniklidis Georgios Chrysikopoulos Constantinos Χρυσικοπουλος Κωνσταντινος Elsevier Solanum lycopersicon Endophytes Heavy metal toxicity alleviation Nanoagroparticles