Scientific publications
Dongmo Lekagne Joseph Blaise
Irénée Somda
Plant
In Cameroon, tomato yields remain low due to attacks by pathogens and insects. <i>Fusarium oxysporum</i> f.sp. <i>lycopersici </i>(FOL) is a fungus responsible for <i>Fusarium </i>wilt, a disease responsible for important economic losses. To contribute to the control of this pathogen, the stimulatory effect of the tomato defence system of extracts of plants in the tomato/FOL interaction was evaluated. Tomato plants were treated with the aqueous extracts (AE) of <i>Callistemon citrinus</i> (<i>C. citrinus</i>), <i>Cymbopogon citratus</i> (<i>C. citratus</i>), and <i>Oxalis barrelieri</i> (<i>O. barrelieri</i>) at 10% (W/V). After 4 days of spraying with the extracts, the plants were inoculated with a virulent strain of <i>Fusarium oxysporum</i> f.sp. <i>lycopersici</i> (FOL) in pots experiments. Tomato roots were used to determine the contents of phenols, proteins, carbohydrates, amino acids (AA) and proline. The activities of antioxidant enzymes were evaluated: ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPX) and superoxide dismutase (SOD). The results showed that treatment of tomato plants with extracts and their infection with FOL induced an increase in the contents of phenols, proteins, carbohydrates, lipids, amino acids and proline in tomato roots, an increase in APX, GPX, SOD activities and a reduction in CAT activity. Our results suggest that the increase and reduction of enzymatic activities, and the increase in the synthesis of some metabolites could mitigate the oxidative damage that takes place during the expansion of the pathogen. Aqueous extracts of <i>C. citrinus</i>, <i>C. citratus</i> and <i>O. barrelieri</i> could be used as natural products to stimulate the tomato defence system against FOL.
