Fungal Phytotoxins and Their Biological Interactions

Fungal phytotoxins are a diverse array of low-molecular-weight secondary metabolites produced by phytopathogenic and saprotrophic fungi. These compounds range from polyketides and terpenoids to nitrogen-containing molecules and nonenolide lactones, many of which exert potent effects on plant physiology. By targeting photosynthetic machinery, disrupting membrane integrity, modulating hormone signalling and inducing oxidative stress, phytotoxins facilitate colonisation by necrotrophic pathogens and shape host specificity. At the molecular level, host-specific toxins bind to defined plant receptors, whereas non-host-specific toxins often provoke broader tissue damage through reactive oxygen species and vesicular trafficking interference. Advances in analytical chemistry and high-throughput metabolomics have clarified the biosynthetic pathways underpinning toxin production and revealed structure–activity relationships critical to their potency. Beyond disease development, fungal phytotoxins hold promise as environmentally benign herbicides and biofungicides, offering new tools for integrated pest management. Understanding their global distribution, modes of action and potential off-target effects is essential for harnessing their benefits while safeguarding crop health and ecosystem balance.

Research from Nature Portfolio

Innovative metabolomics approaches have been applied to classify legume-associated Ascochyta and Phoma species by their phytotoxin profiles. Using liquid chromatography–mass spectrometry combined with multivariate chemometrics, researchers demonstrated high intra-species consistency and pronounced inter-species diversity in secondary metabolite fingerprints. This chemotaxonomic framework aligns metabolic clusters with phylogenetic relationships, offering a powerful tool to predict biosynthetic capacities in uncharacterised taxa and to guide discovery of novel phytotoxins.

Fungal Phytotoxins and Their Biological Interactions publication trend

The graph below shows the total number of articles in fungal phytotoxins and their biological interactions across all publications each year (not limited to Nature Index journals).

Technical terms

Phytotoxin: A bioactive secondary metabolite produced by fungi that is toxic to plants.

Necrotroph: A type of fungal pathogen that kills host tissue and derives nutrients from dead cells.

Secondary metabolite: A low-molecular-weight compound not directly involved in growth or development but often mediating ecological interactions.

Polyketide: A class of secondary metabolites synthesised by polyketide synthases, often with diverse ring structures and bioactivities.

Nonenolide: A ten-membered lactone ring structure found in certain phytotoxins with herbicidal and antimicrobial properties.

Chemotaxonomy: The classification of organisms based on characteristic chemical profiles, typically of secondary metabolites.

Reactive oxygen species (ROS): Highly reactive molecules derived from oxygen that can damage cellular components and trigger defence responses.

References

1. Status of Phytotoxins Isolated from Necrotrophic Fungi Causing Diseases on Grain Legumes. International Journal of Molecular Sciences (2023).
2. Specialized Metabolites Produced by Phytotopatogen Fungi to Control Weeds and Parasite Plants. Microorganisms (2023).
3. Effects of Phytotoxic Nonenolides, Stagonolide A and Herbarumin I, on Physiological and Biochemical Processes in Leaves and Roots of Sensitive Plants. Toxins (2023).
4. Phytotoxic Secondary Metabolites from Fungi. Toxins (2021).
5. Use of metabolomics for the chemotaxonomy of legume-associated Ascochyta and allied genera. Scientific Reports (2016).
6. Effect of Adjuvants on Herbicidal Activity and Selectivity of Three Phytotoxins Produced by the Fungus, Stagonospora cirsii. Plants (2020).