Developing Ag2O and Ag2O/TiO2 nanostructures as a new strategy for control late blight of potato caused by Phytophthora infestans

The nanostructures of silver oxide and silver oxide-titanium dioxide composite were synthesized and tested for their potential to direct antifungal activity against P. infestans, under laboratory, greenhouse and field conditions. Furthermore, the ability of the synthesized nanoparticles to activate the expression of defensive genes was investigated. The effect of Ag2O and Ag2O/TiO2 nanostructures on the growth properties of potato plants was studied. The results showed that Ag2O and Ag2O/TiO2 significantly inhibited the radial growth of Phytophthora infestans relative to the untreated control under laboratory conditions. The results indicated that the most effective treatment in controlling this disease was azoxystrobin followed by Ag2O/TiO(2 )and Ag2O, recording 82.7, 81.4 and 80.7% efficacy, respectively under greenhouse conditions. Additionally, under field conditions, the most effective treatment in controlling the disease was recorded by azoxystrobin followed by Ag2O/TiO2 and Ag2O with 79.9, 67.7 and 64.1, respectively, compared to the non-treated control. Regulatory and defensive genes included in jasmonic acid (JA)/ethylene (ET) signaling pathways were expressed in potato plants treated with Ag2O and Ag2O/TiO2 composite at a level 2-3 times higher than the control. Potato treatments with Ag2O and Ag2O/TiO2 composite compared to azoxystrobin application led to significant improvement in potato growth and productivity. This is the first report of Ag2O and Ag2O/TiO2 nanoparticles used as new and ecofriendly fungicide alternatives against this pathogen.