Wheat root exudates suppress faba bean Fusarium wilt disease

Continuous cultivation of faba beans often results in a high occurrence of Fusarium wilt. Nevertheless, this issue can be successfully managed through wheat-faba bean intercropping. Our objective is to elucidate the function of non-host wheat in combating faba bean Fusarium wilt. We assessed the impact of wheat on the development of faba bean Fusarium wilt through field and pot experiments, and examined and identified the compounds in the root exudates of wheat. The influence of wheat root exudates on Fusarium commun mycelial growth and spore multiplication was investigated through indoor culture experiments. Wheat-faba bean intercropping significantly reduced the occurrence of Fusarium wilt in field trials. Root separation experiments in pots indicated that wheat root exudates might play a vital role in this outcome. The exogenous addition of wheat root exudates to faba bean grown alone notably decreased the occurrence and severity of Fusarium wilt. Furthermore, the exogenous addition of wheat root exudates effectively hindered the growth and reproduction of Fusarium commun's mycelium. And, wheat root exudates contained six compounds with relatively high concentrations, including salicylic acid, p-hydroxybenzoic acid, tartaric acid, malic acid, glutamic acid, and threonine, all of which inhibited the growth and spore formation of Fusarium commun. In a wheat-faba bean intercropping system, these six compounds found in the root exudate of non-host wheat can help control Fusarium wilt in faba bean by inhibiting the mycelial growth and sporulation of Fusarium commun.