Metabolomics profiling reveals p-aminobenzoic acid enhances resistance to Fusarium head blight in wheat

Fusarium head blight (FHB) not only causes severe yield losses but also mycotoxin contamination in wheat, posing a serious threat to food security and public health. The mechanisms of resistance to FHB in wheat are critical for effective prevention and control of the pathogen. In this research, we investigated and analyzed the metabolite changes induced by FHB colonization in the FHB-resistant cultivar Lianmai12 through Fusarium graminearum inoculation and mock inoculation. A total of 1001 metabolites were detected, 109 of which were significantly changed due to FHB infection. The majority of these 109 metabolites belonged to alkaloids, flavonoids, phenolic acids, lipids and organic acids. The most enriched KEGG pathways were plant hormone signal transduction and phenylpropanoid biosynthesis, which may constitute the major defence responses to FHB challenge. The metabolite p-aminobenzoic acid (PABA) significantly suppressed the growth of mycelia and the production of conidia in vitro. Further studies revealed that spraying PABA at early anthesis on wheat spikes reduced the development of FHB disease. These results provide preliminary insights into the metabolic basis of resistance in Lianmai12 and will be beneficial in the development of potential biocontrol agents against FHB.