Mycoparasitism and Nitric Oxide Signaling in Fungal Pathogens

Mycoparasitism—the ability of one fungus to parasitise another—constitutes a critical ecological interaction with direct applications in biocontrol. Mycoparasitic fungi deploy a suite of cell-wall-degrading enzymes, secondary metabolites and specialised signalling networks to recognise, invade and suppress host fungi. Concurrently, nitric oxide (NO) has emerged as a versatile signalling molecule in fungal biology, modulating growth, development, virulence and stress adaptation. The dynamic balance of NO synthesis, largely via nitric oxide synthase–like activities or nitrate/nitrite reductases, and NO detoxification through S-nitrosoglutathione reductase (GSNOR) or flavohaemoglobins, underpins fungal responses to host-derived nitrosative stress. In plant-pathogenic fungi, fine-tuned NO homeostasis governs the formation and function of infection structures—such as appressoria—and influences expression of virulence genes. In mycoparasites, crosstalk between reactive oxygen species (ROS), NO and mitogen-activated protein kinase (MAPK) pathways orchestrates host recognition and penetration. A deeper understanding of NO-mediated signal transduction alongside mycoparasitic effector deployment offers prospects for enhancing biological control agents and mitigating fungal diseases in crops.

Research from Nature Portfolio

Recent studies have elucidated transcriptional control of nitrosative stress responses in a major cereal pathogen. A pioneering transcription factor recruits a chromatin-remodelling complex to activate genes involved in detoxification of reactive nitrogen species, thereby enhancing fungal growth and virulence under nitrosative challenge. A counter-regulatory repressor modulates this recruitment, and its targeted degradation under nitrosative stress further amplifies stress-responsive gene expression. Complementary work in a model filamentous fungus has validated endogenous NO production during hyphal growth and spore formation. Fluorescent probes revealed intracellular NO peaks correlating with developmental transitions. Scavenging NO led to impaired hyphal extension and conidiation, whereas exogenous NO restored these processes, indicating that NO acts as a developmental signal in fungi.

Mycoparasitism and Nitric Oxide Signaling in Fungal Pathogens publication trend

The graph below shows the total number of articles in mycoparasitism and nitric oxide signaling in fungal pathogens across all publications each year (not limited to Nature Index journals).

Technical terms

Mycoparasitism: The parasitic interaction in which one fungus attacks and derives nutrients from another fungus.

Nitric oxide (NO): A gaseous free radical that functions as a signalling molecule in diverse biological processes, including fungal development and pathogenesis.

Nitrosative stress: Cellular damage or signalling alterations resulting from elevated reactive nitrogen species, notably NO and its derivatives.

S-nitrosylation: A post-translational modification involving covalent attachment of an NO group to a cysteine thiol on a protein, affecting its function.

Appressorium: A specialised infection structure formed by many plant-pathogenic fungi to penetrate host tissues.

SWI/SNF complex: An ATP-dependent chromatin-remodelling assembly that alters nucleosome positioning to regulate gene transcription.

S-nitrosoglutathione reductase (GSNOR): An enzyme that degrades S-nitrosoglutathione, thereby regulating cellular NO availability and reversing protein S-nitrosylation.

References

1. De‐nitrosylation Coordinates Appressorium Function for Infection of the Rice Blast Fungus. Advanced Science (2024).
2. Nitric Oxide in Fungi: Production and Function. Journal of Fungi (2024).
3. Interplay of two transcription factors for recruitment of the chromatin remodeling complex modulates fungal nitrosative stress response. Nature Communications (2021).
4. Identification and functional analysis of endogenous nitric oxide in a filamentous fungus. Scientific Reports (2016).
5. Mycoparasitism illuminated by genome and transcriptome sequencing of Coniothyrium minitans, an important biocontrol fungus of the plant pathogen Sclerotinia sclerotiorum. Microbial Genomics (2020).