Aflatoxin B1 Control by Various Pseudomonas Isolates

Area of Science:

• Agricultural Science
• Microbiology
• Biotechnology

Background:

• Climate change increases fungal diseases in crops, necessitating reduced chemical pesticide use.
• Aspergillus flavus produces aflatoxins, harmful mycotoxins posing risks to food safety and agriculture.
• Sustainable biocontrol agents are crucial for integrated pest management strategies.

Purpose of the Study:

• To evaluate the efficacy of 50 Pseudomonas isolates from corn rhizospheres as biocontrol agents against Aspergillus flavus.
• To investigate the impact of Pseudomonas isolates on aflatoxin B1 (AFB1) production and related compounds.
• To elucidate the mechanisms underlying AFB1 inhibition by Pseudomonas isolates.

Main Methods:

• Co-culturing 50 Pseudomonas isolates with Aspergillus flavus in solid and liquid media.
• Quantifying aflatoxin B1 (AFB1) and related compounds using high-performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS).
• Analyzing fungal growth and identifying AFB1 biosynthetic intermediates and degradation products.

Main Results:

• Several Pseudomonas isolates significantly reduced or completely inhibited AFB1 production and related compounds.
• AFB1 reduction was associated with the accumulation of biosynthetic intermediates or degradation products.
• Three isolates completely blocked AFB1 production without affecting fungal growth, suggesting pathway inhibition.
• Bacterial bioactive compounds may induce fungal oxidoreductases, laccases, or trigger non-enzymatic degradation pathways.

Conclusions:

• Specific Pseudomonas isolates demonstrate potent biocontrol capabilities against Aspergillus flavus by inhibiting aflatoxin biosynthesis.
• These findings support the development of novel bacterial-based biocontrol agents for sustainable agriculture.
• The study opens avenues for discovering new bacterial bioactive compounds with potential applications in mycotoxin management.