Role of lipid metabolism through bioremediation of fusaric acid in germinating peanut seedlings

The effect of Bacillus subtilis on the contents of total lipids, neutral lipids, phospholipids and fatty acids in cotyledonary leaves of peanut (Arachis hypogaea L. cv. `Giza 6') was studied in the presence and absence of the mycotoxin fusaric acid. In experiments conducted in a water culture in test tubes, the amount of total lipids was decreased by fusaric acid and increased by B. subtilis; combined treatment reduced the amount. With respect to the effect of fusaric acid on neutral lipids, a non-significant increase in diacylglycerol, significant decreases in triacylglycerol and sterol, and significant increases in sterol ester and non-esterified fatty acids, were obtained, whereas B. subtilis had the opposite effect. Generally, the amounts of the detected phospholipid fractions and the percentages of unsaturation index as well as fatty acids (palmitic, stearic and oleic) were reduced by fusaric acid. Linoleic acid, on the other hand, showed a reverse response: it was increased by fusaric acid alone or in combination with B. subtilis, the increase in the first case being greater than in the second, whereas linoleic acid disappeared in the B. subtilis treatment.