CodY constrains β-cypermethrin degradation by regulating physiological adaptation and soil ecological performance in <i>Bacillus cereus</i> GW-01.
CodY negatively regulates β-cypermethrin degradation in Bacillus cereus, suggesting potential targets for enhancing microbial bioremediation of pesticides.
Where it sits
this study against the rest of the sermorelin corpusSummary and findings
The study investigated the role of CodY in β-cypermethrin degradation by Bacillus cereus GW-01. The ΔcodY mutant showed accelerated β-cypermethrin removal and altered physiological traits compared to the wild type. Complementation restored the wild-type phenotype, confirming CodY as a negative regulator.
Abstract
β-cypermethrin (β-CY) is a widely used pyrethroid insecticide, yet the regulatory mechanisms that determine microbial degradation efficiency remain unclear. Here, we examined the role of the global nutrient-responsive regulator CodY in β-CY degradation by <i>Bacillus cereus</i> GW-01 using a wild-type strain, an in-frame <i>codY</i> deletion mutant, and a complemented strain. Loss of <i>codY</i> shortened the growth lag phase under β-CY stress and accelerated β-CY removal across 50-200 mg/L, reducing the apparent half-life from 3.61 to 12.62 d in the wild type to 2.42-9.61 d in Δ<i>codY</i>. Complementation largely restored the wild-type phenotype, confirming CodY as a negative regulator of β-CY dissipation. Transcriptomic and physiological analyses showed that Δ<i>codY</i> reallocated cellular functions toward branched-chain amino acid metabolism, transport, redox adjustment, envelope remodeling, adhesion, and biofilm formation. Consistently, the mutant exhibited higher cell-surface hydrophobicity, stronger auto-aggregation, enhanced biofilm formation, increased superoxide dismutase (SOD) activity, and lower lipid peroxidation. In soil microcosms, Δ<i>codY</i> also outperformed the wild type in both non-sterilized and sterilized soils, shortening β-CY half-lives by 13.5% and 22.8%, respectively. Community profiling further showed that Δ<i>codY</i> altered bacterial and fungal succession during remediation, with stronger early selection, later bacterial richness recovery, and a more modular co-occurrence network. These results show that CodY restricts β-CY degradation by constraining both catabolic readiness and surface-associated stress adaptation. Targeting global regulatory nodes may therefore improve microbial remediation of hydrophobic pesticide residues in soil.
Background
This study addresses the regulatory mechanisms of microbial degradation of β-cypermethrin, a common pyrethroid insecticide. Understanding these mechanisms is crucial for improving bioremediation strategies. Previous research has not fully elucidated the role of global regulators like CodY in this process.
Methods
The study utilized Bacillus cereus GW-01 strains, including a wild-type, a codY deletion mutant (ΔcodY), and a complemented strain. β-cypermethrin degradation was measured across concentrations of 50-200 mg/L. Transcriptomic and physiological analyses were conducted to assess cellular function reallocation.
Results
The ΔcodY mutant demonstrated a reduced β-cypermethrin half-life from 3.61–12.62 days to 2.42–9.61 days. Physiological changes included increased cell-surface hydrophobicity, auto-aggregation, biofilm formation, and SOD activity. In soil microcosms, ΔcodY outperformed the wild type, reducing β-cypermethrin half-lives by 13.5% and 22.8% in non-sterilized and sterilized soils, respectively.
Interpretation
The findings suggest that CodY acts as a negative regulator of β-cypermethrin degradation by limiting catabolic readiness and stress adaptation. While the effect size is statistically significant, its clinical relevance for bioremediation practices depends on broader ecological impacts. Confounding factors include the use of a single bacterial strain and laboratory conditions.
Key findings
- β-cypermethrin half-life reduced from 3.61–12.62 d to 2.42–9.61 d in ΔcodY.
- ΔcodY showed higher cell-surface hydrophobicity and stronger auto-aggregation.
- Enhanced biofilm formation and increased SOD activity in ΔcodY.
- ΔcodY shortened β-cypermethrin half-lives by 13.5% and 22.8% in soil.
- Altered bacterial and fungal succession in ΔcodY during remediation.
Limitations
- Not reported in abstract.