الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
SUMMARY
1- Tomato crop is a widespread vegetable crop worldwide. Vascular wilt disease is due to Fusarium oxysporumf.sp. lycopersici (FOL). It is a soil-borne pathogen in the class Hyphomycetes to fusarium fungi that causes vascular wilt of tomato that may cause a 10-90% loss in the yield.
2- Molecular Docking is a method that was used in structure-based drug design because it can predict the binding-conformation of a small molecule (ligand) with (target) in binding sites. AutoDock 4.2 program was based on Lamarckian Genetic Algorithm (LGA) which is a hybrid genetic algorithm with local search algorithm which had used free-energy scoring to calculate the binding energy and inhibition constant.
3- In this study, we had used chemoinformatics search for several compounds against endo-and exo- polygalacturonase of Fusarium oxysporum f. sp. Lycopersici fungs. A group of different naturalcompounds which include alkaloids, flavonoids, terpenoids, sulfur compounds, and phenols were used as inhibitors to several pathogenes.
4- Allium plants such as onion plants contain between 1 and 5 %of non-protein sulfur amino-acids, including S-E-prop-1-enyl-L-cysteine S-oxide, S-3-allylsulphinyl-L-alanine, and S-methylcysteine sulfoxide have satisfactory binding interactions and inhibition constant with endo and exopolygalacturonases. These compounds were extracted from white onion bulb Giza 20 and detected in the onion extract LC/MS analysis. The Inhibitory effect of these compounds for endo and exopolygalacturonase enzymes were confirmed experimentally by determination of the enzyme activity in the presence and the absence of these compounds. White onion extract had about 45% inhibition percentage of the endo and exopolygalacturonases activity.
The enzyme kinetic study showed an increase in the Km value with stable V-max value in presence of 7µg/µL of the onion extract. Also, In-vitro experiment of inhibition of F. oxysporumgrowth in presence20% and 40% of onion extract showed inhibition percentages of 47% and 53% respectively.
In-vivo experiment of inhibition of F. oxysporum growth assay inpresence 10%, 20% and 40% of onion extract showed the lowest number for disease severity comparison with control .
5- The results indicated that onion extract inhibits Fusarium growth through inhibition of exo and endopolygalacturonases. The inhibitory effect of onion extract could be due to its contents of S-E-prop-1-enyl-L-cysteine S-oxide, S-3-allylsulphinyl-L-alanine and S-methylcysteine sulphoxide, which have excellent binding interactions and inhibition effects on both exo and endopolygalacturonases enzymes of Fusarium oxysporum f. sp. Lycopersici .
6- We strongly recommend using these natural compounds in the control of Fusarium oxysporum f. sp. Lycopersici infestation to diminish the loss in the yield