Phytomediated Silver Nanoparticles (AgNPs) Embellish Antioxidant Defense System, Ameliorating HLB-Diseased 'Kinnow' Mandarin Plants.

Citrus production is harmed worldwide by yellow dragon disease, also known as Huanglongbing (HLB), or citrus greening. As a result, it has negative effects and a significant impact on the agro-industrial sector. There is still no viable biocompatible treatment for Huanglongbing, despite enormous efforts to combat this disease and decrease its detrimental effects on citrus production. Nowadays, green-synthesized nanoparticles are gaining attention for their use in controlling various crop diseases. This research is the first scientific approach to examine the potential of phylogenic silver nanoparticles (AgNPs) to restore the health of Huanglongbing-diseased 'Kinnow' mandarin plants in a biocompatible manner. AgNPs were synthesized using Moringa oleifera as a reducing, capping, and stabilizing agent and characterized using different characterization techniques, i.e., UV-visible spectroscopy with a maximum average peak at 418 nm, scanning electron microscopy (SEM) with a size of 74 nm, and energy-dispersive spectroscopy (EDX), which confirmed the presence of silver ions along with different elements, and Fourier transform infrared spectroscopy served to confirm different functional groups of elements. Exogenously, AgNPs at various concentrations, i.e., 25, 50, 75, and 100 mgL-1, were applied against Huanglongbing-diseased plants to evaluate the physiological, biochemical, and fruit parameters. The findings of the current study revealed that 75 mgL-1 AgNPs were most effective in boosting the plants' physiological profiles, i.e., chl a, chl b, total chl, carotenoid content, MSI, and RWC up to 92.87%, 93.36%, 66.72%, 80.95%, 59.61%, and 79.55%, respectively; biochemical parameters, i.e., 75 mgL-1 concentration decreased the proline content by up to 40.98%, and increased the SSC, SOD, POD, CAT, TPC, and TFC content by 74.75%, 72.86%, 93.76%, 76.41%, 73.98%, and 92.85%, respectively; and fruit parameters, i.e., 75 mgL-1 concentration increased the average fruit weight, peel diameter, peel weight, juice weight, rag weight, juice pH, total soluble solids, and total sugarby up to 90.78%, 8.65%, 68.06%, 84.74%, 74.66%, 52.58%, 72.94%, and 69.69%, respectively. These findings enable us to develop the AgNP formulation as a potential citrus Huanglongbing disease management method.

Proximate composition, fungal isolation and contamination of aflatoxin B1 in chickpea seeds from the Punjab, Pakistan.

Chickpea, Cicer arietinum L., is a nutrient rich crop that is widely cultivated and consumed in Pakistan. However, chickpea is highly prone to fungal growth leading to contamination with aflatoxins, the most potent carcinogen found in nature. In this study, fifty chickpea seed samples were collected from the local markets of the Punjab, Pakistan, to evaluate their nutritional quality, fungal and AFB1 contamination. Proximate analysis suggested that chickpea seeds contained 5.5-6.93% moisture, 62.24-63.24% carbohydrates, 22.75-23.44% protein, 4.99-5.4% fat, 5.62-5.84% fiber and 2.92-3.16% ash. Morphological identification techniques revealed fourteen fungal species belonging to six fungal genera from which Aspergillus flavus was the leading contaminant. AFB1 analysis revealed that sixty-two percent samples were contaminated with AFB1. All the AFB1 positive samples contained AFB1 level more than 2 ppb and 12.9% samples contain AFB1 level more than 20 ppb, exceeded the maximum limit (ML) assigned by EU and USA (FDA & FAO) respectively. The results of the present studies reported that chickpea is a highly contaminated commodity in terms of fungi and AFB1 that's why further investigations and monitoring are required to reduce the fungal and AFB1 contamination. These baseline data are an initial step in the effort to deal with this significant food safety issue.

Light and scanning electron microscopic characterization of aflatoxins producing Aspergillus flavus in the maize crop.

Maize (Zea mays L.) is considered as one of the main cereals, used as a source of food, forage, and processed products. The loss of maize productivity is reported due to effect on roots, stalks, ears, and kernels mainly caused by many fungi. Among these fungal pathogens of maize, Aspergillus flavus (A. flavus) are the most prevalent that produces highly toxigenic aflatoxins that are highly carcinogenic to the consumers. The present study is confined to isolate and characterize the A. flavus from maize seeds for accurate identification that can be helpful for determination and management of aflatoxins in maize crop. Eighty stored seed samples of maize were collected from warehouses where seeds are stored for food and feeding purposes. For the isolation of A. flavus, Potato Dextrose Agar was used. Isolated fungi were identified macro and microscopically using light microscope and scanning electron microscope. A total of 212 Aspergillus isolates were identified based on macro-morphological and micro-morphological characteristics. The results showed that A. flavus colonies were granular, flat with yellow-green to deep yellow-green colony color having a white border and compact, spherical spore heads. Rapid rate of growth was observed maturing in about 3-5 days. In microscopic features, A. flavus have apically swollen conidiophores with various conidia bearing cells in long and dry chains. Spherical conidial heads were split into several columns ranging 300-400 µm in diameter. This will be helpful for farmers, researchers and traders in future for correct identification of sources of aflatoxins. RESEARCH HIGHLIGHTS: Maize seed samples were collected from Pothohar region of Pakistan. The fungi were isolated on PDA. Aspergillus flavus was identified macro-morphologically by observing growth rate, colony color and texture. Furthermore, these fungi were identified micro-morphologically by using light and scanning electron microscope. The 212 Aspergillus flavus strains were isolated and identified.