Green synthesis of silver nanoparticles using Cakile maritima seed extract: Molecular, antifungal and physiological studies

Abstract

The synthesis of nanoparticles from plants is a biological process recognized to be environmentally approving, and inexpensive, which is preferred over physical and chemical processes. Plant extracts synthesize many types of metal nanoparticles with high biological activity. Because of its toxicity, aflatoxin poses a significant risk to contaminated corn kernels. However, this study focused on exploring in vitro the antifungal capacity of AgNPs biosynthesized from the seed extract of Cakile maritima on the growth of Aspergillus flavus isolated from Egyptian corn kernels. The anti-Aspergillus activity of AgNPs prepared from C. maritima seed extract was first reported. This investigation was performed to distinguish aflD, aflR, and aflP as three significant genes that contribute to the production of aflatoxin B1 cycle in A. flavus. The results gained by amplifying chosen genes by PCR for the recognition of A. flavus strains correlated significantly with TLC and HPLC outcomes. Samples that tested positive for the production of aflatoxin B1 could show amplification of the three target genes. Total phenols and flavonoids were determined from C. maritima seed extract. The quantitative evaluation of the phenolic compounds of C. maritima seed methanol extract was performed. Chlorogenic acid showed the highest amount (3250.9 μg/g dry weight). AgNPs repressed the mycelial growth and the germination of A. flavus spores more than the crude extract, AgNO3, and the fungicide compared to the negative control. The ultrastructural study of A. flavus mycelium by SEM and TEM exhibited a clear variation between untreated and treated mycelium. The treated mycelium with 10% AgPNs showed severe distortion of mycelia compared to the control, crude extract, AgNO3, and fungicide. The results showed the maximum improvement in root length, shoot length, area of leaf surface, chlorophylls, protein, and carbohydrates of the seedlings of corn were assessed at 30 ppm AgNPs.