Insights into regulating mechanism of mutagenesis strains of Elizabethkingia meningoseptica sp. F2 by omics analysis.

Abstract Vitamin K2 plays an important role in electron transport, blood coagulation, and calcium homeostasis; therefore, researchers have attempted to improve vitamin K2 production in Elizabethkingia meningoseptica. Our previous work revealed that gradient radiation, breeding, and culture acclimation could improve the vitamin K2 yield in Elizabethkingia meningoseptica, but the mechanism remains elusive. Thus, this study is the first which performs genome sequencing of Elizabethkingia meningoseptica sp. F2 as a basis for subsequent experiments and further comparative analyses with other strains. Comparative metabolic pathway analysis of E. meningoseptica sp. F2, E. coli, Bacillus subtilis, and other vitamin K2 product strains revealed that the mevalonate pathway of Elizabethkingia meningoseptica sp. F2 is different in bacteria at the system level. Furthermore, a Quantitative real-time RT-PCR was conducted to determine vitamin K2 biosynthetic gene expression in different developmental phases and strains of Elizabethkingia meningoseptica. The results demonstrated that MenA, MenD, MenH, and MenI of the menaquinone pathway and IDI, HMGR, and GGPPS of the mevalonate pathway had a higher expression compared to the original strain. In addition, isobaric tags for relative and absolute quantitation techniques have been applied in proteomic studies. A total of 67 differentially expressed proteins were identified. These proteins are mainly involved in the oxidative phosphorylation metabolism pathway and the citrate cycle (TCA cycle). Therefore, our results reveal that combined gradient radiation breeding and culture acclimation can promote vitamin K2 accumulation by regulating the vitamin K2 pathway, oxidative phosphorylation metabolism pathway, and the citrate cycle (TCA cycle).