New insights into the antifungal and anti-mycotoxigenic potential of the TickCore3 peptide against Fusarium species causing Fusarium Head Blight

Cereal crops are frequently affected by Fusarium species that are responsible for the devastating fungal disease Fusarium Head Blight (FHB). These Fusarium species are also capable of producing mycotoxins that accumulate in grains. Reducing the use of synthetic fungicides in agriculture while guaranteeing low levels of mycotoxin contamination in crops requires the development of innovative and environment-friendly solutions. TickCore3 (TC3) is the γ-core of the Ixodes ricinus tick defensin DefMT3. This peptide was previously reported as a potent antifungal and anti-mycotoxin agent but was only tested against one strain of Fusarium graminearum , which is only one of the species causing FHB. In this study, we demonstrated that the peptide was active against major Fusarium species infecting wheat and could mitigate the accumulation of various mycotoxins. Fungal susceptibility to TC3 was shown to vary significantly according to the species and the strain as well. We found that TC3 is highly efficient when applied to the spores and has a strong anti-germination activity. Using a FITC-labeled TC3 peptide and confocal microscopy, we showed that TC3 has a strong affinity for the conidia surface and surrounds these fungal structures. Finally, the implementation of in planta tests demonstrated the bioactivity of TC3 when applied on wheat leaves. This study provides additional convincing results supporting the huge potential of TC3 as a novel and efficient anti-fungal agent to control FHB.