Bacillus amyloliquefaciens: A Biological Shield Against Fusarium

Bacillus amyloliquefaciens: A Biological Shield Against Fusarium

Fusarium wilt is a nightmare for many crops—persistent, widespread, and notoriously hard to control. While chemical fungicides are commonly used, they’re increasingly coming under scrutiny. One promising biological alternative is gaining traction: Bacillus amyloliquefaciens.

Case Study: Banana Cultivation with B. amyloliquefaciens W19

A breakthrough was achieved in banana farming in China: the W19 strain was applied to the soil as a bio-organic fertilizer—with impressive results:

• Fusarium wilt was reduced by up to 44%,

• Yields increased by 35% in field trials.

How does it work? Through multiple mechanisms at once:

• Lipopeptide compounds (Iturin, Bacillomycin D, Surfactin) directly attack the fungus.

• Biofilm formation at the root zone helps beneficial microbes establish themselves.

• Production of IAA (a plant hormone) boosts root growth and enhances the plant’s stress resistance.

Additional Evidence: Melon and Cucumber Cultivation

• In greenhouse cucumber trials, B. amyloliquefaciens DHA6 suppressed Fusarium oxysporum through lipopeptide production and activation of plant defense genes.

  • Antioxidative enzymes like catalase and superoxide dismutase were elevated,

  • Plants showed increased overall resistance.

• Field studies in watermelon cultivation, published in Biology & Fertility of Soils, confirmed that a biofertilizer containing B. amyloliquefaciens NJN-6 significantly reduced wilt and improved plant growth.

Mechanisms of Action at a Glance

• Direct Antagonism- Lipopeptides destroy fungal hyphae and inhibit spore development

• ISR Activation - Defense genes (JA/ET pathways and antioxidants) are triggered

• Root Stimulation - IAA and biofilm promote improved nutrient uptake

• Microbiome Restructuring - Fusarium is suppressed, beneficial microbes expand

Conclusion: A Biological Powerhouse Instead of Fungicide

Bacillus amyloliquefaciens—with strains like W19, DHA6, and NJN-6—clearly shows that natural soil microbes are not just an alternative, but in many cases outperform chemical fungicides:

• Less environmental impact and no residue,

• No risk of resistance development,

• Works in synergy with the plant’s own defense mechanisms.

Sources:

Biological Control Agents Against Fusarium Wilt of Banana; doi:10.3389/fmicb.2019.00616

Cyclic Lipopeptides of Bacillus amyloliquefaciens DHA6 Are the Determinants to Suppress Watermelon Fusarium Wilt by Direct Antifungal Activity and Host Defense Modulation; https://doi.org/10.3390/jof9060687

Plant Growth-Promoting Rhizobacteria Strain Bacillus amyloliquefaciens NJN-6-Enriched Bio-organic Fertilizer Suppressed Fusarium Wilt and Promoted the Growth of Banana Plants; https://doi.org/10.1021/jf400038z