The Secret Life of Fungi: How Fusarium Grows in Laboratory Flasks

In Petri dishes, not only discoveries are born but also solutions for saving harvests

Exploring the growth patterns of Fusarium fungi in controlled laboratory conditions

What is Fusarium and Why Is It Dangerous?

Fusarium is one of the most insidious plant diseases, capable of destroying up to 70% of grain crop yields⁴ .

Key Threats

Over 400 species of ascomycete fungi⁴
Causes fusarium wilt, root rot, and head blight⁴
Produces dangerous mycotoxins²

Mycotoxins Produced

Deoxynivalenol (DON)
Zearalenone
T-2 toxin²

Special problem: Fusarium's ability to survive on different plants - not only cultivated cereals but also weeds - expands its ecological niche and complicates control measures² .

Laboratory Home for Fungi: In Vitro Conditions

In vitro research (under controlled laboratory conditions) allows scientists to study Fusarium growth and behavior without the influence of external factors. The basis for cultivation is nutrient media that provide fungi with all necessary substances for growth.

Key Factors for Mycelium Growth

Temperature

Optimal for most Fusarium species is 22-25°C² ⁷

Medium Acidity

pH 4-5 is often optimal for growth and sporulation⁷

Lighting

Some species grow better in darkness, others under cyclic lighting⁷

Carbon Sources

Glucose, sucrose and other carbohydrates⁷

Molecular identification methods such as species-specific PCR and sequencing of TEF1-α and RPB2 genes allow accurate identification of Fusarium species, which is critical for proper experimental design⁴ .

Experiment: How Fungicides Affect Fusarium Growth?

One of the key questions studied in vitro is the sensitivity of different Fusarium isolates to fungicides.

Experimental Methodology

1. Fungal Isolation

Plant samples were collected from fields, sterilized and placed on Potato Dextrose Agar (PDA) nutrient medium. Grown fungi were purified and identified² .

2. Molecular Identification

DNA was extracted from mycelium, PCR was performed with species-specific primers for accurate species identification² .

3. Fungicide Testing

Three fungicides were tested - metconazole, prothioconazole and tebuconazole at various concentrations. Mycelium growth inhibition was assessed after 3-7 days of incubation at 22±2°C² .

4. Efficacy Calculation

The fungicide concentration required for 50% growth inhibition (EC50) was determined with regression model construction² .

Results and Analysis

The study revealed significant differences in fungicide sensitivity between Fusarium species and isolates.

Table 1. Fusarium Species Sensitivity to Fungicides (EC50 values in mg/L)

Fusarium Species	Metconazole	Prothioconazole	Tebuconazole
F. graminearum	0.15-2.90	0.12-23.6	0.09-15.6
F. culmorum	0.18-1.50	0.35-8.9	0.21-7.8
F. avenaceum	0.22-0.85	0.45-3.2	0.30-2.9
F. sporotrichioides	0.25-1.20	0.28-5.6	0.25-4.5

Table 2. Effect of Isolation Source on Tebuconazole Sensitivity

Isolation Source	Average EC50 Value (mg/L)
Weeds	0.15-2.30
Wheat	0.28-4.50
Rapeseed	0.35-5.80
Peas	0.45-6.20

Scientific Significance

This experiment revealed important patterns:

Isolates from weeds showed higher sensitivity to fungicides compared to isolates from cultivated plants² .
F. graminearum demonstrated the greatest variation in EC50 values, indicating high genetic plasticity of this species² .
At very low concentrations (0.00025–0.025 mg/L), fungicides were ineffective against most species except F. avenaceum² .

Scientist vs. Fungus: Research Arsenal

Table 3. Key Reagents for Studying Fusarium Growth In Vitro

Reagent/Equipment	Function in Research
Potato Dextrose Agar (PDA)	Basic nutrient medium for fungal cultivation
Spezieller Nährstoffarmer Agar (SNA)	Medium for stimulating sporulation
Triazole fungicides (metconazole, tebuconazole)	Suppression of mycelium growth and sporulation
Species-specific PCR primers	Molecular identification of Fusarium species
Chromato-mass spectrometry	Analysis of secondary metabolites and mycotoxins

Modern Fusarium research increasingly uses multiple approaches (genomics, transcriptomics, proteomics) that provide a holistic picture of molecular mechanisms of growth and pathogenicity⁴ . For example, studying the expression of chitin synthase (ChsV) and folate blocker (FUBT) genes helps understand how the fungus protects itself from fungicide exposure and maintains pathogenicity³ .

Invisible Connection: Fusarium and Environment

Gallic Acid Effect

Chinese researchers studied the effect of gallic acid (a phenolic compound found in plants) on F. oxysporum and discovered a paradoxical effect: although mycelium growth and sporulation were suppressed, the activity of pathogenic factors (pectinase, protease, cellulase) significantly increased⁷ . This explains why in some cases stressful conditions may not weaken but rather enhance pathogen aggressiveness.

Rhizosphere Bacteria

Another research direction is using rhizosphere bacteria for Fusarium biocontrol. Studying antagonism mechanisms (competition for nutrition, antibiotic production, induction of plant systemic resistance) allows development of environmentally safe plant protection methods.

Future of Fusarium In Vitro Research

Synthetic Biology

Using CRISPR/Cas9 tools for targeted gene editing⁶

Systems Biology

Studying metabolic networks to create strains producing useful compounds⁶

Microbiome Research

Understanding complex interactions in plant-pathogen-microbiome system

Studying Fusarium mycelium growth in vitro continues to be a powerful tool in scientists' hands, allowing revelation of the secrets of life of these dangerous but incredibly interesting fungi. Each Petri dish is an opportunity to find a new solution to one of the oldest problems in agriculture.