White mustard (Sinapis alba L.) residues with enhanced potential as soil biofumigant by using controlled elicitation during cultivation

Elicitors are stressors of biotic nature responsible for the adaptation of plants to cope with environmental stresses. Brassicae species (as white mustard) produce glucosinolates (GSs) that modify soil microbial communities and suppress soil-borne plant diseases. This research aimed to evaluate the glucosinolates levels in white mustard after elicitation with salicylic acid (SA), hydrogen peroxide (H2O2), chitosan (QN), and a commercial oligosaccharide (Xh), as well as the impact on the biofumigant activity of elicited plant residues mixed with fresh manure against soil-borne populations of Fusarium oxysporum. White mustard plants were treated with SA, H2O2, QN, and Xh. White mustard residues of the QN treatment (100 mg/mL) were further evaluated either in combination or not with fresh cow manure for biofumigant activity against F. oxysporum. Spectrophotometric and GC–MS techniques, respectively, determined GSs in white mustard plant organs. Significant increases in GSs in all plant organs except roots were found. The best treatment was chitosan 100 mg/mL, showing increases in leaves, flowers, and seeds. These plants treated with chitosan and mixed with fresh cow manure used in the biofumigation of soils displayed a reduction from 1600 CFU/g of soil to 50 CFU/g of soil F. oxysporum native population. Results suggested that controlled elicitation might increase the amount of GSs on white mustard, especially in the aerial parts; thus, elicited white mustard can be valorized as a potent biofumigant when mixed with fresh cow manure; thus, these green amendments might be a sustainable alternative in agriculture to help in crop management.