Phytotoxic Secondary Metabolites from Fungal Sources

Phytotoxic secondary metabolites are low-molecular-weight compounds produced by a diverse range of fungal species that exert potent effects on plant physiology. These substances—among them polyketides, nonribosomal peptides, terpenoids and hybrid molecules—have evolved as chemical tools to facilitate host colonisation, induce necrosis or modulate defence responses. In agricultural settings, they underpin the severity of many fungal diseases and contribute to significant yield losses, while in natural ecosystems they influence plant community structure and competition. Beyond their pathological roles, certain phytotoxins inspire the development of target-specific bioherbicides with rapid environmental degradation, offering sustainable solutions to invasive weeds. Advances in metabolomic profiling, synthetic biology and structure–activity studies have elucidated mechanisms ranging from disruption of photosynthetic membranes to deregulation of stomatal function and initiation of programmed cell death. The global relevance of this field spans food security, ecological management and green agrochemical innovation, as researchers strive to harness these compounds both to understand plant–pathogen interactions and to design eco-friendly weed control agents.

Research from Nature Portfolio

Recent studies have explored synthetic modifications of the iso-pimarane diterpene sphaeropsidin A, originally identified as a fungal phytotoxin. By introducing lipophilic substituents at the C15–C16 alkene, researchers generated hemisynthetic derivatives that trigger pronounced endoplasmic reticulum swelling and potent proteasomal inhibition in mammalian cells—activities distinct from those of the parent compound. These findings demonstrate how targeted structural tuning of fungal diterpenes can uncover novel bioactivities and inform rational design of analogues with tailored modes of action.

Research from all publishers

A 2024 review of metabolites from fungi of the genus Diplodia underscores their production of diverse polyketide and terpenoid compounds with broad-spectrum antimicrobial and phytotoxic effects. Structure–activity analyses highlight how minor modifications in polyketide frameworks influence toxicity against various plant hosts and suggest roles in fungal virulence. Studies on a synthetic analogue of radicinin, (±)-3-deoxyradicinin, reveal its capacity to induce chloroplast-targeted oxidative stress in tomato, causing uncontrolled stomatal opening, lipid peroxidation and activation of a chloroplast-specific cell-death pathway. Complementary ecotoxicological work evaluates radicinin and (10S,11S)-epi-pyriculol for buffelgrass biocontrol, demonstrating rapid photodegradation of radicinin under sunlight and greater stability of epi-pyriculol in aqueous media. These data support their potential as selective bioherbicides with minimal non-target impact.

Phytotoxic Secondary Metabolites from Fungal Sources publication trend

The graph below shows the total number of articles in phytotoxic secondary metabolites from fungal sources across all publications each year (not limited to Nature Index journals).

Technical terms

Secondary metabolite: A natural product not essential for normal growth but mediating ecological interactions.

Phytotoxin: A compound produced by an organism that is toxic to plants.

Polyketide: A class of natural products assembled from acetyl and malonyl subunits, often with diverse biological functions.

Terpenoid: A family of natural products derived from isoprene units, including mono-, sesqui- and diterpenes.

Bioherbicide: A biologically derived agent used to control unwanted plants with limited non-target effects.

References

1. The current status on secondary metabolites produced by fungi of the genus Diplodia associated with plants. Phytochemistry Reviews (2024).
2. New hemisynthetic derivatives of sphaeropsidin phytotoxins triggering severe endoplasmic reticulum swelling in cancer cells. Scientific Reports (2024).
3. (±)-3-Deoxyradicinin Induces Stomata Opening and Chloroplast Oxidative Stress in Tomato (Solanum lycopersicum L.). International Journal of Molecular Sciences (2023).
4. Insights into the Ecotoxicology of Radicinin and (10S,11S)-(—)-epi-Pyriculol, Fungal Metabolites with Potential Application for Buffelgrass (Cenchrus ciliaris) Biocontrol. Toxins (2023).