Fusarium wilt of tomato ( Lycopersicon esculentum ) caused by Fusarium oxysporum f. sp. lycopersici is one of the most important diseases that affect this crop worldwide. This study aimed to biosynthesise nanosilver (AgNPs) using Chaetomium globosum , to evaluate its in vitro antifungal activity against pathogenic F. oxysporum and in vivo control of tomato seedlings wilt in the greenhouse. AgNPs was tested for its in vitro antifungal potential against F. oxysporum using poisoned food technique on three different growth media, agar well diffusion assay, inhibition of colony formation (CFU), and tested for its potency to control seedlings wilt upon its use at different concentrations (50, 100 and 500 mg/l) and for different incubation periods (0, 1, 2 and 4 h). Results indicated that C. globosum succeeded to biosynthesise AgNPs with maximum UV/vis absorbance around 420–450 nm, spherical in shape with particle size of 11–14 nm according to Transmittance electron microscope and displayed high purity recorded through X‐ray diffraction (XRD). I n vitro studies revealed high antifungal activity of AgNPs against F. oxysporum noticed especially at a concentration of 500 mg/l and after incubation period for 4 h. The CFU of F. oxysporum on potato dextrose agar (PDA) medium decreased significantly on increasing the concentration and time of incubation with AgNPs. In the greenhouse, AgNPs caused appreciable enhancement in the growth parameters of tomato seedlings such as; root, shoot fresh weight, and height of seedlings in soil infested with F. oxysporum compared with the control. In addition, AgNPs reduced the severity of wilt disease by 90% observed through decreasing the number of wilted seedlings especially after placing their roots in 500 mg/l of AgNPs suspension for 4 h prior to soil infestation with the pathogen. This study recorded for the first time that C. globosum has the ability to synthesise AgNPs which showed significant in vivo antifungal potential observed through control of Fusarium wilt of tomato seedlings, in addition to enhancing their growth parameters in the greenhouse.

Aflatoxin B1 is one of the most deleterious types of mycotoxins. The application of an endophytic fungus for biodegradation or biosuppression of AFB1 production by Aspergillus flavus was investigated. About 10 endophytic fungal species, isolated from healthy maize plants, were screened for their in vitro AFs-degrading activity using coumarin medium. The highest degradation potential was recorded for Trichoderma sp. (76.8%). This endophyte was identified using the rDNA-ITS sequence as Trichoderma harzianum AYM3 and assigned an accession no. of ON203053. It caused a 65% inhibition in the growth of A. flavus AYM2 in vitro. HPLC analysis revealed that T. harzianum AYM3 had a biodegradation potential against AFB1. Co-culturing of T. harazianum AYM3 and A. flavus AYM2 on maize grains led to a significant suppression (67%) in AFB1 production. GC-MS analysis identified two AFB1-suppressing compounds, acetic acid and n-propyl acetate. Investigating effect on the transcriptional expression of five AFB1 biosynthesis-related genes in A. flavus AYM2 revealed the downregulating effects of T. harzianum AYM3 metabolites on expression of aflP and aflS genes. Using HepaRG cell line, the cytotoxicity assay indicated that T. harazianum AYM3 metabolites were safe. Based on these results, it can be concluded that T. harzianum AYM3 may be used to suppress AFB1 production in maize grains.

The mycoflora and mycotoxins contamination of commercial maize and rice grains collected from local markets of the major five zones of the province of Cairo, Egypt, represented by 20 different districts were studied. A total number of about 23 species belonging to 12 different genera of fungi were isolated and identified. About 70% of the samples were infected with Aspergillus flavus and Aspergillus niger, with percentages of 33%, 40% recovered from maize and 46%, 27% recovered from rice, respectively. The percentages of infection of maize ranged from 16% to 142%. The percentages of infection of rice seeds ranged from 6% to 93%. Total aflatoxins and fumonisins detected in maize averaged 9.75 and 33 µg/kg, respectively. Total aflatoxins and fumonisins detected in rice averaged 5.15 and 1014 µg/kg, respectively.

This study aimed to green synthesize nanosilver (AgNPs) using black tea extract and use it as a nanopreservative to increase the shelf life of stored apple fruits. Ultraviolet visible absorption (UV–vis) analysis of AgNPs recorded two λ max values at 260 and 452 nm. Transmission electron microscope and dynamic light scattering analyses showed that AgNPs are spherical in shape and have an average size of 20 and 170.6 nm, respectively, with a zeta potential of −20.06 mV. An in vitro assay confirmed the antifungal potential of AgNPs against M. fructigena when applied at 200 mg/L and preincubated for 4 days, reducing the radial growth by 96.1%. At the same dose and preincubation period, AgNPs caused a significant reduction in the diameter and fresh weight of brown rotted lesions in apple fruits artificially coinoculated with the pathogen by 77.4% and 84.4%, respectively. AgNPs caused the leakage of proteins and DNA from M. fructigena conidia and did not express cytotoxicity against the human HaCaT cell lines. Accordingly, green synthesized AgNPs are eco-friendly and economical and do not pose harm to human health; thus, they could be used as an effective nanopreservative in apple fruit stores to reduce the incidence of brown rot disease.