The LysR orchestrates expression of dibenzofuran catabolic genes in a dioxins-degrader Rhodococcus sp. by direct...

Aromatics contamination has posed a significant threat to global ecosystems. During bioremediation, transcriptional regulation of aromatics catabolic genes serves as a subtle switch for controlling functional organisms, particularly in engineering synthetic microbes. LysR-type transcriptional regulators and the quorum sensing LuxR family regulators LuxR solos, are prevalent in bacteria, participating in regulating metabolism and physiological activities. However, their coordination for catabolic genes regulation remains poorly understood. In this study, we examined the relationship between LysR and LuxR solo and the underlying mechanisms for transcriptional regulation of dibenzofuran-catabolic genes in Rhodococcus sp. strain p52, which harbors distinct dioxins-catabolic gene clusters on plasmids pDF01 and pDF02. Our results demonstrated that the self-regulatory LysR encoded on pDF02 repressed the expression of catabolic genes on the same plasmid through binding to the dbfA promoter, and dibenzofuran relieved the inhibition of LysR. Additionally, the LysR inhibited the expression of the luxR solo located on pDF01, which regulates the catabolic genes on that plasmid. Transcriptomic and proteomic analyses revealed that the LysR acted as a master switch for metabolism regulation, influencing central metabolism and oxidative phosphorylation, besides dibenzofuran peripheral pathway degradation. This study broadens our understanding of bacterial transcriptional regulatory hierarchies during aromatics biodegradation.