Analysis of the Antagonistic Effect of Dibutyl Phthalate on

The fungus Magnaporthe oryzae (M. oryzae) triggers rice blast, significantly endangering the agricultural production. We identified a potential antifungal metabolite, Dibutyl Phthalate (DBP), from the fermentation broth of Stenotrophomonas genitulata WXY53 through mass spectrometry analysis. DBP inhibited the growth of M. oryzae hyphae by 44.52%, inhibited the formation of appressorium with an inhibition rate of 85.07% at 8 h and 68.97% at 24 h, and directly delaying the colonization of invasive hyphae on plants. Treatment with DBP substantially decreased the lesion count by 57.61% and 43.77% in rice and barley, respectively. The metabolomics and transcriptome sequencing analyses showed that DBP affects lipid metabolism, the MAPK signaling pathway, carbohydrate metabolism, and other metabolic processes of M. oryzae. Significant differences were found in the levels of reactive oxygen species, enzymatic activity, lipid metabolism, conductivity, extracellular protein content and membrane fluidity after DBP treatment. Scanning electron microscopy revealed that the hyphae and conidia fractured, wrinkled, and deformed. DBP does not significantly affect plant seedlings growth and has an LC50 of 11.93 mg/L for Danio rerio. And DBP may have broad-spectrum antifungal activity. In this study, we provided a reference for the ability of DBP to inhibit M. oryzae and revealed its antifungal mechanism.