Guttation

Fungal guttation droplets are extracellular secretions composed of a concentrated mix of biologically active compounds that the fungus expels during growth, often under humid or nutrient-rich conditions.

These droplets typically contain a blend of secondary metabolites such as mycotoxins (e.g., gliotoxin, fusarin C), antimicrobial compounds, and organic acids, alongside various peptides and low-molecular-weight proteins.

They often include sugars, amino acids, and ions that reflect the fungus’s internal metabolic state.

Many droplets are also rich in redox-active molecules and metal-chelating agents like siderophores, which aid in nutrient acquisition or microbial competition.

The exact composition is species-specific—Aspergillus, Fusarium, and Trichoderma guttation fluids, for example, are chemically distinct and may include pigments or UV-protective compounds.

These exudates are not waste products but are thought to play roles in interspecies signaling, defense, or pathogenicity, offering a chemically dense snapshot of the fungus’s ecological strategies.