Synergistic Effect of Fusarium oxysporum, Silver Nanoparticles, and Abiotic stresses on Secondary Metabolite Production in Ipomoea batatas Callus Culture

Abstract

This study investigates the synergistic effect between biosynthetic silver nanoparticles (AgNPs) using the fungus Fusarium oxysporum, and abiotic stresses (such as proline), in enhancing the production of secondary compounds within the callus culture of the sweet potato plant (Ipomoea batatas). The successful formation of AgNPs was confirmed by UV spectroscopy at 437 nm, and scanning electron microscope images, where particle diameters ranged between 25.5 – 50.2 nm with an average of 37.85 nm.The optimal combination to stimulate callus growth was 2 mg/L of naphthalene acetic acid (NAA) and 1 mg/L of benzyl adenine (BA), with 1.5 g of solid callus obtained in a yellowish-white color. Treatment with AgNPs at concentrations of 3 and 5 mg/L, resulted in significant increases in both soft and dry weight compared to proline treatment and control. The soft weight of the callus treated with 3 mg/L of AgNPs was about 8.60 g, and the dry weight was 2.10 g. As for the active compounds, HPLC analysis showed a significant increase in the production of flavonoids, most notably rutin, which reached 95.9 mg/L at a concentration of 5 mg/L of AgNPs, compared to 74.9 mg/L in the control and 66.0 mg/L in the intact plant. In addition, quercetin content increased to 88.7 mg/L under 5 mg/L AgNPs treatment, compared to 70.1 mg/L in the control and 59.8 mg/L in the intact plant. Similarly, kaempferol reached 80.1 mg/L under AgNPs treatment, while it was 66.8 mg/L in the control and 52.6 mg/L in the intact plant. In addition to significant increases in other compounds such as quercetin and kaempferol. An improvement in alkaloid content was also observed, reaching 2.15% in the treatment of AgNPs compared to 0.97% in the intact plant. These findings demonstrate that silver nanoparticles, which are abiotic catalysts, can effectively stimulate secondary metabolic pathways, making them a promising tool in plant tissue culture techniques to enhance the production of compounds with high therapeutic value.