5132
Sally Ibrahim Abd El-Fattah El-Sayed
Potential hazards of toxigenic Fusarium species in maize grains in Egypt
Fusarium sp, Fusarium toxins, maize grains, morphological
The present study focused on the risks of Fusarium contamination and the potential accumulation of its toxins in maize grains in Egypt. These were achieved throughout the study of fungal profile (Fusarium sp.) of the samples, Fusarium toxins namely, fumonisin B1, zeralenone and deoxynivalenol as well as the potential production of fumonisins by Fusarium isolates. The mode of infection through stalk and root of different commercial hybrids by F. verticilloides was also followed. Finally, use different Bacillus strains and different extracts of certain microorganisms as a bio control for reduction the growth of Fusarium was studied. Two hundred isolates of Fusarium was purified and identified. Fusarium verticilloides was the predominate species in maize grains. Identification of 100 isolate were confirmed by using PCR all which revealed that isolates belonged to F. verticilloides. There was 95% compatibility between both morphological and molecular identification. Most of isolates had a great variability for a production of fumonisins. In tested maize samples, fumonisin B1 was the predominant Fusarium toxins but all under the permissible limits with exception of one sample whichcontained 9.8 mg kg-1. On contrast, zeralenone was detected in 37% of the tested samples, 54% of the positive samples had levels exceeded the permissible limits. In the meantime deoxynivalenonl was not detected in all samples. The commercial maize hybrids had a higher resistance against stalk infection than root infection. Bacillus strains appeared a highly antagonistic against all tested Fusarium isolates. Diethyl ether and ethyl acetate extracts of Streptomyces sp. showed highly activity against all tested isolates. Two compounds were identified from each extracts, Octadecenoic acid, methyl ester and Pentadecanoic acid, 14-methyle1-, methyl ester from diethyl ether extract and Hexadecane and Hexadecanoic acid, methyl ester from ethyl acetate extract. The chloroform extract of Pseudomonus sp. was recorded a high activity against all tested Fusarium isolates and two compounds were identified Pyrolidine and 5-methyl-1-hydroxy phenazine. On the other hand, one compound was identified, Butylated hydroxyl toluene, which had a high activity from Hexane extract of Nannochloropsis oculata.
2016
Ph.d
Al-Azhar
Science