Nano-Metals Forming Bacteria in Egypt. II. Efficacy towards Some Bacterial Soft Rot/Blackleg Genera ex vivo and Bio-Control in vivo as Eco-Friendly Therapeutic against Dickeya Solani

Abstract

The antibacterial activity of Cu, Fe, Co, and ZnNPs which were formed by Enterococcus thailandicus, Pseudomonas putida, Marinobacter hydrocarbonoclasticus, and P. geniculate sequentially was tested against some soft rot/blackleg genera. The effects of NPs were recorded on bacterial DNA, proteins, and carbohydrates concentration of Pectobacterium carotovorum, Enterobacter cloacae (soft rot), and Dickeya solani (soft rot/blackleg). Treated cells showed degradation in the DNA isolated, and a decrease in proteins, and carbohydrates concentration compared with untreated cells. The treated cells using SEM showed collapsed, and small pits in the cell wall. Internal changes using TEM showed penetration of NPs inside the tested bacterial cells, the appearance of periplasmic space, formation vacuoles, and condensation of cytoplasm. Disease severity ex vivo of tuber infected with tested genera demonstrated that NPs treatment didn't show any rotted tissue compared with untreated. FeNPs were tested to control soft rot/blackleg disease caused by D. solani in comparison with copper pesticide. Present data recorded an increase in shoot and root length, in addition to, increase in dry and fresh weight, compared with either infected or healthy plants. In studying the ability of treated potato (Solanum tuberosum) seedlings with NPs to uptake and accumulate FeNPs from the soil, ICP-OES recorded a small increase in Fe content of treated plants compared with untreated. FeNPs can be used to control soft rot/blackleg disease caused by D. solani instead of copper pesticide and can be considered as a new and alternative approach to traditional disease management methods, and also increase the nutritional value of the plants