The development of new green fungicides is an effective
way to
solve the resistance of agricultural pathogens and plays an important
role in promoting high-quality and sustainable development of modern
agriculture. In this project, a series of aryloxy-, arylthio-, and
arylamino-containing acethydrazide derivatives were designed, synthesized,
and characterized by 1H nuclear magnetic resonance (NMR), 13C NMR, and high-resolution mass spectrometry (HRMS). The
fungicidal bioassays indicated that some compounds showed excellent
and broad-spectrum fungicidal activity, and the structure–activity
relationship was discussed. The in vivo fungicidal activity demonstrated
that compounds C4 and D8 exhibited good
preventative effects against Fusarium graminearum infecting wheat leaves, of which the preventative activity of compound D8 was almost equal to that of the positive agents. Transmission
electron microscopy (TEM) observation revealed that the plasma membrane
in the C4-treated F. graminearum hyphal cells was severely contracted and separated with the cell
wall, coupling with the visible lysosomes and the disappeared cytoplasm
and organelles, which may be the reasons for the shriveled and even
ruptured hyphae observed by scanning electron microscopy (SEM). Subsequently,
transcriptomics and metabolomics were performed to further elucidate
the fungicidal mechanism. The regulatory networks of differential
genes and metabolites in plasma membrane-related sphingolipid metabolism,
linoleic acid metabolism, α-linoleic acid metabolism, and arachidonic
acid metabolism were constructed and elaborated. Additionally, preliminary
investigation of seeding growth suggested that compounds C4 and D8 may have different degrees of influence on the
growth indicators of wheat seedlings; however, this effect may be
negligible as the plant grows.