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One of the important technical obstacles in the study of many filamentous fungi is the development of efficient transformation system. Transformation of filamentous fungi is difficult because they have a cell wall and for most frequently used approaches preparing of protoplast is necessary. Protoplast preparation is batch-dependent and often frustrating work. In this study, a modified method was introduced for gene transfer to the plant pathogenic fungus, Fusarium graminearum, the major causal agent of Fusarium Head Blight disease in small grains. This protocol was based on protoplast-PEG method. Age of mycelia, enzymes exposure time and mycelium/enzyme ratio were optimized for the purpose of protoplast preparation. The outcome showed that the best result for protoplast preparation was obtained when 1.5 × 10⁵ spores were let germinate for 6 h then exposed to 10 ml of enzyme solution for 3 h. The effect of other parameters that might enhance transformation yields including PEG concentration, DNA quantity and number of protoplasts was also examined. The most efficient condition for transformation involved the use of 10⁶ protoplasts, 20 µg DNA and 30% PEG (w/v). In the course of this study, a simple and appropriate modified protocol for transformation of F. graminearum was established. The method introduced is also more economical and faster than other current methods.

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In order to reduce the economic losses and life risks caused by microbial pathogens, the use of natural substances as antimicrobial compounds seems to be an effective way to control the presence of pathogenic bacteria. In this study, the chemical composition of onion essential oil was determined by gas chromatography–mass spectrometry (GC-MS). The methods in disk diffusion agar (DDA) and well diffusion agar (WDA) were used to investigate the inhibition zone diameter, micro-dilution broth was used to measure the minimum inhibitory concentration (MIC) and pour-plate technique was also used for minimum bactericidal/fungicidal (MBC/MFC) concentration. A total of 20 chemical volatiles (approximately 100% of onion essential oil compounds) were identified. The compounds Trisulfide dipropyl, Disulfide dipropyl, n-Decane and Furfuryl methyl sulfide with 20.67, 16.18, 13.51 and 10.23% of the main constituents of onion essential oil, respectively. The results of WDA showed that onion essential oil had the most and the least effect on Gram-positive bacteria Staphylococcus aureus with a diameter of 15 mm and Gram-negative bacteria Pseudomonas aeruginosa with a diameter of 10 mm, respectively. The results of MIC onion essential oil for Staphylococcus aureus, Listeria innocua, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Candida albicans 512, 512, 512, 512, 512 and 1024 mg/mL, respectively. In general, the results of this study showed that the antimicrobial effect of onion essential oil can be somewhat different depending on the type of microorganism.