Antifungal activity of zinc oxide nanoparticles in Fusarium oxysporum-Solanum lycopersicum pathosystem under controlled conditions

Antifungal activity of zinc oxide (ZnO) and ZnO nanoparticles (ZnO NPs) was evaluated on the control of Fusarium oxysporum Schltdl. (Nectriaceae) under laboratory and greenhouse conditions. In vitro evaluation, poisoned culture media was prepared, and an explant was placed in the centre of solid medium. The experimental design was completely randomized with 18 treatments. Mycelial growth and conidia concentration were evaluated. Subsequently, three treatments (3,000, 1,500, 100 ppm) of ZnO NPs and ZnO were chosen for their evaluation in the greenhouse in tomato plants of Floradade variety under a randomized block design. Inoculation was carried out with a 1x10(7) conidia per mL suspension of F. oxysporum, when the plants presented the third pair of true leaves. Later, the application of different concentrations of ZnO and ZnO NPs was carried out; in this investigation, the incidence and severity and plant height were evaluated into account to determine the treatment effect on F. oxysporum. In vitro, the best treatments in mycelial growth inhibition were the high concentrations of ZnO NPs from 1,600 to 3,000 ppm with 81%-83%, and in the sporulation of the fungus, they were also those that inhibited from 82.57% to 83.85%. In greenhouse, the treatments that reached the highest plant height were ZnO NPs from 1,500 to 3,000 ppm, with a range of 166.0-175.40 cm, with a severity on the scale of 0.40-0.80 and an incidence of 20%-40%. ZnO NPs have a potential application as an antifungal agent and can be used to control the spread of F. oxysporum in tomato plants, in addition to improving the promoter effect related to the Zinc activity as a precursor in auxins synthesis, cytokinins and gibberellins biosynthesis, as well as the induction of higher activity of antioxidant enzymes useful in response to the pathogens attack.