General nitrogen regulation protein NtrC regulates the expression of nitrile hydratase and the synthesis of extracellular polysaccharide in Ensifer adhaerens CGMCC 6315.

Ensifer adhaerens CGMCC 6315 contains two nitrile hydratases, CnhA and PnhA, which both convert the neonicotinoid insecticide acetamiprid to its amide metabolite. Here, we report that upregulation of PnhA and CnhA expression is related to nitrogen metabolism. Proteomic analysis showed that general nitrogen regulation protein NtrC was upregulated under nutrient deprivation. We thus constructed a Δ ntrC mutant strain of E. adhaerens CGMCC 6315. In the Δ ntrC strain, when cells were cultured in minimal salts medium supplemented with ammonium chloride, acetamiprid degradation and the expression of cnhA and pnhA were enhanced relative to those in wild-type E. adhaerens CGMCC 6315. In addition, NtrC negatively regulates synthesis of extracellular polysaccharides in this bacterium. The germination rate of soybean seeds was improved by inoculation with the Δ ntrC strain of E. adhaerens CGMCC 6315 compared with the wild-type. This study is the first to report regulation of the expression of nitrile hydratase by NtrC, which is important for the practical remediation of pesticide pollution. [Display omitted] • General nitrogen regulation protein NtrC regulating the expression of nitrile hydratase was firstly reported. • NtrC negatively regulates extracellular polysaccharide synthesis in Ensifer adhaerens CGMCC 6315. • The NtrC mutant of Ensifer adhaerens CGMCC 6315 has higher ability to degrade acetamiprid and promote plant growth. [ABSTRACT FROM AUTHOR]