Bacillus cereus GW-01 promotes Pak Choi (Brassica chinensis L.) growth by reducing β-Cypermethrin and regulating plant metabolism, phyllosphere and rhizosphere microbial communities.

Beta-Cypermethrin (β-CY) is a widely used insecticide that negatively affects plant growth and contaminates crops. In this study, we investigated the ability of Bacillus cereus GW-01 to degrade β-CY and promote the growth of Pak choi (Brassica chinensis L.). GW-01 degraded β-CY on Pak choi leaves, achieving over 90 % degradation after 9 days. It improved photosynthetic efficiency, increased chlorophyll content by 36.6 %, and enhanced antioxidant activity. Compared to plants treated with β-CY alone, GW-01 treatment boosted net photosynthetic rate by 27.78 %, reduced reactive oxygen species by 29.45 %, and increased glutathione by 32.36 %. Furthermore, GW-01 reduced the activities of key enzymes in ethylene biosynthesis, leading to lower ethylene and salicylic acid levels. GW-01 exhibited growth-promoting traits, including siderophore production and indole-3-acetic acid synthesis. We first reported the B. cereus colonizing multiple plant compartments and altering the microbial community, offering potential for developing biofertilizers to degrade pesticide residues and improve crop quality.