# Guttation (DD-064) > Guttation, the release of liquid droplets, is common across the fungal kingdom. How much a fungus produces depends heavily on conditions such as the growth medium and temperature, and its biological role is only partly understood. Lab studies have found the droplets carry secondary metabolites and proteins. Penicillium expansum exudates held 20 specialized metabolites, including the mycotoxins patulin and citrinin, and 194 proteins. Droplets from ochratoxin-producing Penicillium strains held up to 11 times more ochratoxin A than the mycelium beneath them. Toxigenic Stachybotrys chartarum (black mold) produced droplets with up to several thousand nanograms of satratoxins per milliliter. Enzymes such as β-glucosidase, catalase and peroxidase have been measured in the exudates of plant-pathogenic fungi. - Department: Nature (also Science) - First published: 2025-08-03 - Last updated: 2025-08-03 - Permalink: https://detailenjoyer.com/case/guttation/ - Author: Marcus Easterling (DetailEnjoyer), The Detail Department ## Quick facts - **DD-064-F01**: Guttation droplets from some Penicillium molds hold far more ochratoxin A than the mycelium that produces them, up to 11 times more. _(Write-up · Exhibit C (Concentrated toxins))_ - **DD-064-F02**: Toxigenic black mold (Stachybotrys chartarum) can produce guttation droplets laden with satratoxins. _(Write-up · Exhibit D (Black mold))_ ## Write-up Fungi that sweat droplets. The beads can carry enzymes, metabolites and sometimes mycotoxins. 1. **Common but not well understood**: Guttation is common across the fungal kingdom. How much a fungus produces depends heavily on conditions such as growth medium and temperature, and its biological role has been explored only partly. 2. **What's in the drops**: Researchers have found mycotoxins, antimicrobials, insecticidal and antiviral compounds, and proteins in fungal exudate droplets. 3. **Concentrated toxins**: In ochratoxin-producing Penicillium strains, droplets held 92.7–8,667 ng of ochratoxin A per milliliter. That was up to 11 times more than the mycelium beneath them and up to 176 times more than the agar. 4. **Black mold**: Fourteen of 15 Stachybotrys isolates produced droplets. In the toxigenic ones, the droplets held macrocyclic trichothecenes (satratoxins G and H) at up to several thousand nanograms per milliliter. 5. **Enzymes and proteins**: Penicillium expansum exudates contained 20 specialized metabolites, including patulin and citrinin, and 194 proteins, mostly involved in breaking down plant walls. Exudates of plant-pathogenic fungi show activity of enzymes such as β-glucosidase, catalase and peroxidase. 6. **A possible role**: In salt-tolerant Aspergillus versicolor strains from a former uranium-mining site, droplet formation was linked to tolerance of salt and metals. The droplets held about 2,900 detectable substances. ## Related case files - [Eukaryotic (DD-003)](https://detailenjoyer.com/case/eukaryotic/): Fungi are eukaryotes: a tour of the organelles inside every eukaryotic cell. - [The Glacier That Bleeds (DD-725)](https://detailenjoyer.com/case/the-glacier-that-bleeds/): Another strange liquid that seeps out of nature: brine flowing from Taylor Glacier. ## Reel vs. record - **Confirmed**: fungal guttation droplets contain enzymes, secondary metabolites and, in some species, mycotoxins. Penicillium expansum droplets held patulin, citrinin and 194 proteins. [Biomolecules review; Postharvest Biology and Technology] - **Note**: Context on 'sometimes toxins': the toxin can be concentrated. Ochratoxin A in Penicillium droplets reached up to 11 times the level in the mycelium, and toxigenic Stachybotrys droplets held thousands of nanograms of satratoxins per milliliter. [Mycopathologia; Mycotoxin Research] - **Nuance**: guttation isn't constant. How much a fungus produces depends largely on growth medium and temperature, and most measurements come from lab cultures on agar. [Biomolecules review] - **Missing context**: why fungi guttate is only partly understood. One study linked droplet formation to salt and metal tolerance in Aspergillus versicolor. [Biomolecules review; PMC 2022] - **Footage note**: the clips show a small mushroom with water beads on its stem and cap. They don't show which species it is or what the droplets contain, so nothing here implies that particular mushroom is toxic. [Reel footage] ## Video: Guttation: Fungi That Sweat Droplets - Duration: 18.6 s · Published: 2025-08-03 - File: https://detailenjoyer.com/assets/videos/DM6qCZ7syBJ.mp4 ### Transcript DID YOU KNOW? Fungal guttation is the process where fungi excrete droplets of liquid from specialized structures or hyphal tips, often visible as tiny beads of moisture on the surface of fungal colonies. These droplets contain a mix of water, enzymes, secondary metabolites, and sometimes toxins, reflecting the fungus' metabolic activity. NOW YOU KNOW! ## Questions & answers **Q: What does guttation intensity depend on most?** A: Its biological role is only partly understood. _(Source: Write-up · Exhibit A (Common but not well understood) · Fungal guttation, a source of bioactive compounds, and its ecological role: a review (Biomolecules, 2021))_ **Q: Which mycotoxin was concentrated in Penicillium droplets?** A: It reached up to 11 times the level in the mycelium. _(Source: Write-up · Exhibit C (Concentrated toxins) · Fungal guttation, a source of bioactive compounds, and its ecological role: a review (Biomolecules, 2021); Guttation droplets of Penicillium nordicum and P. verrucosum contain high concentrations of ochratoxin A and B (Mycopathologia, 2007))_ **Q: Which toxins were found in Stachybotrys droplets?** A: These are macrocyclic trichothecenes. _(Source: Write-up · Exhibit D (Black mold) · Stachybotrys spp. and the guttation phenomenon (Mycotoxin Research, 2014, PubMed))_ **Q: How many proteins were found in Penicillium expansum exudates?** A: Most were involved in breaking down plant walls. _(Source: Write-up · Exhibit E (Enzymes and proteins) · Fungal guttation, a source of bioactive compounds, and its ecological role: a review (Biomolecules, 2021); Exudates secreted: Penicillium expansum's means of conquering the external environment (Postharvest Biology and Technology, 2025))_ **Q: In Aspergillus versicolor, droplet formation was linked to what?** A: The strains came from a former uranium-mining site. _(Source: Write-up · Exhibit F (A possible role) · Salt and metal tolerance involves formation of guttation droplets in species of the Aspergillus versicolor complex (PMC, 2022))_ ## Sources - [Fungal guttation, a source of bioactive compounds, and its ecological role: a review (Biomolecules, 2021)](https://www.mdpi.com/2218-273X/11/9/1270) - [Guttation droplets of Penicillium nordicum and P. verrucosum contain high concentrations of ochratoxin A and B (Mycopathologia, 2007)](https://link.springer.com/article/10.1007/s11046-007-9003-1) - [Stachybotrys spp. and the guttation phenomenon (Mycotoxin Research, 2014, PubMed)](https://pubmed.ncbi.nlm.nih.gov/24619360/) - [Exudates secreted: Penicillium expansum's means of conquering the external environment (Postharvest Biology and Technology, 2025)](https://doi.org/10.1016/j.postharvbio.2025.113614) - [Salt and metal tolerance involves formation of guttation droplets in species of the Aspergillus versicolor complex (PMC, 2022)](https://pmc.ncbi.nlm.nih.gov/articles/PMC9498632/) ## Cite this case file Easterling, Marcus. "Guttation." The Detail Department (DetailEnjoyer), case file DD-064, last updated Aug 3, 2025. https://detailenjoyer.com/case/guttation/