耻垢分枝杆菌MSMEG_0418调控能量代谢及链霉素敏感性的功能研究OA

Succinate dehydrogenase(SDH),which serves as a crucial interface between the tricarboxylic acid(TCA)cycle and the electron transport chain,acts as a central hub governing the growth,persistence,and host immune responses of Mycobacterium tuberculosis(Mtb).Consequently,targeting Mtb bioenergetic metabolism has become a prominent strategy for developing novel anti-tuberculosis drugs.Due to the slow growth and high biosafety requirements of Mtb,its closely related model species,Mycobacterium smegmatis,is widely adopted as an ideal surrogate for investigating Mtb gene functions.The MSMEG_0418 gene encodes a core subunit of the SDH complex in M.smegmatis;however,its specific role in mycobacterial energy metabolism and antibiotic tolerance remains unclear.In this study,we constructed an MSMEG_0418 knockout strain(ΔMs0418)and its complemented strain in M.smegmatis using a markerless homologous recombination strategy.Phenotypic changes were assessed through growth curve analysis,minimum inhibitory concentration(MIC)determination,and time-kill curve assays,while the underlying molecular regulatory network was investigated via transcriptome sequencing(RNA-seq).Phenotypic analysis revealed that ΔMs0418 displayed specific hypersensitivity to streptomycin,with a significantly accelerated killing rate.Transcriptomic profiling demonstrated that genes involved in core energy metabolism pathways—including oxidative phosphorylation and the TCA cycle—as well as adenosine triphosphate synthase complex-related genes,were markedly downregulated in the ΔMs0418 mutant.In contrast,upregulated genes were primarily confined to membrane lipid remodeling and stress repair pathways,and no systematic metabolic compensation was observed.These findings indicate that the loss of MSMEG_0418 broadly impairs basal energy production and metabolic homeostasis in the bacterium.In conclusion,MSMEG_0418,as a key component of the SDH complex,plays a critical role in maintaining mycobacterial energy metabolism and antibiotic resistance.The above results lay a foundation for elucidating the pathogenic mechanisms of its Mtb homolog and provide a reliable scientific basis for the development of next-generation anti-tuberculosis agents targeting bioenergetic metabolism.