Nematodes avoid and are killed by Bacillus mycoides-produced styrene

Area of Science:

• Agricultural Science
• Microbiology
• Nematology

Background:

• Root-knot nematodes cause significant global crop damage.
• Bacillus species show promise for biological nematode control due to nematicidal metabolites.

Purpose of the Study:

• To identify and characterize nematicidal compounds from Bacillus mycoides strain R2.
• To evaluate the efficacy of Bacillus mycoides R2 and its nematicidal compound for controlling root-knot nematodes.

Main Methods:

• Isolation and identification of Bacillus mycoides strain R2 from tomato rhizosphere.
• Nematicidal activity assays against Caenorhabditis elegans and Meloidogyne incognita.
• Pot experiments to assess biocontrol efficiency and styrene's mode of action via olfactory pathways.

Main Results:

• Bacillus mycoides R2 demonstrated high nematicidal activity, achieving 90.94% control of Meloidogyne incognita in pot experiments.
• Styrene was identified as the primary nematicidal compound, with a median lethal concentration of 4.55 μg/ml.
• Styrene acts as a nematode repellent, primarily affecting olfactory neurons and G protein signaling pathways.

Conclusions:

• Bacillus mycoides R2 is a promising biocontrol agent against root-knot nematodes.
• Styrene, produced by B. mycoides R2, is an effective nematicide and repellent.
• Registration of styrene as a nematode repellent and biocontrol agent is recommended for crop protection.