Allelopathic Interactions of Solanum stramonifolium Jacq. Might Be Used for Meloidogyne incognita Management

The root-knot nematode (RKN) Meloidogyne incognita infects a large host range causing enormous agricultural losses. Although the control of this pest is mainly based on the use of chemical pesticides, natural alternatives are currently being largely considered, especially the use of plant-derived molecules, as allelochemicals and plant extracts. Solanum stramonifolium is a plant of the Solanaceae family and has been studied for its potential to control RKN, either by the use aqueous extracts of its seeds, or due to its immunity to nematode penetration. Our studies demonstrate that S. stramonifolium has an efficient defense mechanism against RKN completely preventing its penetration into its root system. Additionally, the compounds exuded by this plant in the soil can affect nematode infection in nearby grown Nicotiana benthamiana (-89% biomass for treatment I respectively, and -61% and +57% of galls for the treatments and Solanum lycopersicum (-79% biomass for treatment I, and -83% of galls for the treatments I and II). Herein, external (ED, < 3.5 kDa) and internal (ID, > 3.5 kDa) dialysates were prepared from the extract of S. stramonifolium seeds. Arabidopsis thaliana Col-0 inoculated with RKN treated with the dialysates showed a reduced gall diameter in 45% and 35% for ED and ID respectively. Additionally, a significant reduction in biomass was observed in germinated seeds after treatment with ID. In addition, Arabidopsis roots showed changes in their ploidy levels when treated with ED and ID, compared to the untreated control, indicating its effect on endoreduplicating cells. Finally, a partial identification of glycoalkaloids present in the ED and root extracts may help to explain plant immunity to root-knot nematode infection. Results obtained shed light on the defense mechanisms of S. stramonifolium against M. incognita, its allelopathic potential in co-cultivated plants and its biotechnological potential of dialysates obtained from its seeds, representing a strong alternative to the management of RKN in conventional agriculture.