Biofertilizer induces soil disease suppression by activating pathogen suppressive protist taxa

Area of Science:

• Agricultural Science
• Microbiology
• Ecology

Background:

• Sustainable agriculture increasingly relies on soil microbiome manipulation.
• Understanding microbial interactions, especially with predatory protists, is crucial for biofertilizer (BF) efficacy.
• The role of predatory protists in biocontrol and their interplay with resident microbes requires further investigation.

Purpose of the Study:

• To investigate the interactions between biocontrol agents (Bacillus), predatory protists (Cercomonas), and soil pathogens (Ralstonia solanacearum).
• To elucidate the mechanisms underlying biofertilizer-induced disease suppression.
• To highlight the significance of predator-prey dynamics in sustainable agriculture.

Main Methods:

• Long-term field experiments.
• Greenhouse and pot experiments.
• Monitoring microbial growth (Bacillus, Cercomonas) and pathogen presence (R. solanacearum).

Main Results:

• Bacillus significantly stimulated the growth of the predatory protist Cercomonas.
• Cercomonas promoted Bacillus growth, increasing polyketide synthase (PKS) gene detection.
• This positive feedback loop led to the inhibition of the bacterial wilt pathogen Ralstonia solanacearum.

Conclusions:

• A synergistic positive feedback loop exists between Bacillus and predatory protists, enhancing biocontrol efficacy.
• Biofertilizer-induced reduction in plant pathogens is mediated by these microbial interactions.
• Incorporating predator-prey dynamics into agricultural practices can enhance soil-borne disease suppression and promote sustainable ecosystems.