Abstract
Sclerotium rolfsii Sacc. was the cause of both the spoilage and the reduction in quality of peanut seeds as well as the decrease in quality and quantity of the oil during pathogenesis. The application of a biocontrol agent, Bacillus subtilis, counteracted the negative effect of the seedborne pathogen (S. rolfsii) on the chemical and physical properties of the oil content. Moreover, the changes in fatty acids composition of peanut seed oil have been related to a tolerance mechanism against S. rolfsii and to the induction of systemic physiological changes which result in greater improvement of oil quality and quantity.