Abstract
Antifungal impact of silver nanoparticles (AgNPs) was evaluated on the growth, morphological, and biomolecules dynamics of Fusarium culmorum and Alternaria alternata. It was revealed that the different concentrations of AgNPs caused inhibition of fungal growth and deformations of fungal structures especially at high concentrations 40 and 60 ppm of AgNPs. A. alternata conidiospores at 40 ppm of AgNPs was sharply deformed and their longitudinal sections disappeared. On the other hand, these fungi failed to produce conidiospores in the presence of 60 ppm of AgNPs but produced chlamydospores. The effect of AgNPs on amino and fatty acids of F. culmorum was investigated compared with the influence of silver nitrate (AgNO3). AgNPs at different applied concentrations stimulated the synthesis of the most detected amino acids including aspartic acid, threonine, serine, glutamic acid, glycine, alanine, valine, leucine, tyrosine, arginine, proline, and lysine. The concentration of detected amino acids increased with increasing AgNPs up to 60 ppm. Aspartic acid, serine, glycine, alanine, arginine, leucine, and proline concentrations were 11.52, 6.53, 21.51, 12.51, 27.34, 9.40, and 22.17 mu g/ml compared with their concentrations 5.90, 0.34, 21.51, 12.51, 14.97, 6.86, and 9.91 mu g/ml at 40 ppm of AgNPs and AgNO3, respectively. Numerous fatty acids were detected in low percentage in treated F. culmorum with AgNO3 or AgNPs compared with untreated (control). Only butyric was detected in high percentage (29.58 and 33.04% at 20 ppm of AgNPs and AgNO3, respectively) compared with their percentage 15.93% in control.