Multiomics Analysis Of Methyltransferase Mutant And Its Wild Type Under Osmotic Stress

DNA methylation is an important part of epigenetics,and it is an important way to regulate gene expression,and the pgl X gene is a methylated transferase,which plays a major role in the growth of bacteria and physiological metabolism.Lacticaseibacillus paracasei Zhang was isolated from sour horse milk samples of traditional fermentation in Inner Mongolia.It is a good probiotic strain.From the perspective of epigenetics,we compared the growth of L.paracasei Zhang Δpgl X mutant with the wild type under salt stress.A combination of transcriptomic,proteomic and metabolomic analysis was conducted on the bacterial samples grown for 4 h and 10 h,and the results were as follows:(1)Transcriptomic analysis showed that there were 877 differentially expressed genes in the 4-h group,of which 449 were significantly up-regulated and 428 were significantly down-regulated.There were 212 differentially expressed genes in the 10-h group,of which151 were significantly up-regulated and 61 were significantly down-regulated.It is mainly concentrated in fatty acid biosynthesis,histidine metabolism,phosphotransferase system,Staphylococcus aureus infection,galactose metabolism,cationic antimicrobial resistance,two-component system,inositol phosphate metabolism,ascorbic acid and uronic acid metabolism and other metabolic pathways.(2)Proteomic analysis showed 161 differentially expressed proteins in the 4-h group,including 124 significantly up-regulated proteins and 37 significantly down-regulated proteins.There were 75 differentially expressed proteins in the 10-h group,among which 67 proteins were significantly up-regulated and 8 proteins were significantly down-regulated.It is mainly concentrated in the metabolic pathways of pentose and glucuronic acid interconversion,amino sugar and nucleotide sugar metabolism,fructose and mannose metabolism,phosphotransferase system,ascorbic acid and uronic acid metabolism,glycolysis and gluconogenesis,starch and sucrose metabolism,pyruvate metabolism,propionate metabolism,galactose metabolism and citric acid cycle.(3)Metabolomics analysis showed that there were 6 metabolites in 4 h group under osmotic stress.There were 24 different metabolites in 10 h group.It mainly concentrated in sphingolipid metabolism,glycolysis and gluconeogenesis,purine metabolism,steroid hormone biosynthesis,tryptophan metabolism,panquinone and other terpenoid compoundsquinone biosynthesis,glycosaminoglycan degradation,glycine,serine and threonine metabolism,arachidonic acid metabolism,steroid biosynthesis and primary bile acid biosynthesis.In summary,the results of multi-omics combined analysis showed that,in osmotic stress environment,carbohydrate metabolism,lipid metabolism,amino acid metabolism and membrane transport ability of methyltransferase pgl X mutant were enhanced compared with wild strains,indicating that the metabolism and transport ability of strain in the absence of methyltransferase were improved.