Co‐culture of faba bean with wheat provides evidence for intercropping faba bean to alleviate the occurrence of Fusarium wilt under the autotoxic stress of salicylic acid.

The goals of this study were to evaluate the role of salicylic acid (SA) in causing autotoxic stress in the faba bean root system and explore how the co‐culture of faba bean (Vicia faba) with wheat (Triticum aestivum) alleviates this stress. We designed a hydroponic pot experiment to study the effects of exogenous SA on the occurrence of Fusarium wilt, seedling growth, physiological resistance of faba bean and pathogenicity of Fusarium oxysporum f. sp. fabae (FOF). The results showed that SA significantly increased the incidence and disease index of faba bean Fusarium wilt, inhibited the growth of seedlings and reduced the physiological resistance of faba bean. An in vitro study of FOF found that SA increased the ability of the organism to produce fusaric acid, cellulase and pectinase, which increased the susceptibility of faba bean to Fusarium wilt. Interestingly, co‐cultivation with wheat significantly reduced the content of SA in exudates from the faba bean roots, which directly reduced the deleterious effects of SA. In addition, co‐cultivation could increase the activity of peroxidase and catalase, reduce the content of malondialdehyde, thus improving the ability of faba bean to defend itself. In conclusion, we found that SA, as an autotoxic substance, aggravates the occurrence of Fusarium wilt on faba bean and affects the growth of this crop. However, co‐cultivation of faba bean with wheat could alleviate this autotoxicity. This study has discovered a possible mechanism that could explain how co‐cultivation can alleviate the obstacles in cropping systems and control Fusarium wilt. [ABSTRACT FROM AUTHOR]