Expression Modeling And Functional Analysis Of Plantaricin Related Genes In Lactobacillus Plantarum YM-4-3

In modern times,the government,enterprises and consumers are increasingly Concerned about the food safety problems caused by foodborne pathogens.Nowadays,Making use of Chemical preservatives is the main means to ensure the safety on the of tongue.Nevertheless,this kind of food additives have the risk of leading to teratogenesis and cancer.Therefore,discoverying new,safety and efficient biological preservatives are becoming the focus and pressing needs in research of the field.Lactobacillus plantarum is one of the most important industrial fermentation strains,widely esixted Widely exists in the pickled vegetables,yogurt and fermented douche and other fermented foods.it can hydrolyze protein into amino acids and small molecules,endowing Food nutritional value,taste and flavor,it also can reduce Blood pressure,depress cholesterol level,anti-aging,anti-tumor,Promote digestive function.The metabolite of organic acid,Hydrogen peroxide and plantaricin.which are produced by Lactobacillus plantarum YM-4-3 can Effectively inhibit the growth offood-borne pathogens thus,to extend the shelf life of food.In fact,Lactobacillus plantarum will be affected by different factors of environmental stress,containing osmotic stress caused by high salinity,thermalstresscaused by high temperature sterilization,lowtemperature stress caused by frozen,acid stress caused by Fermentation acidity,starvation stress caused by nutritional deficiencies,oxidative stress caused by exposing to the air.these factors can affect Biological activity and metabolic regulation of Lactobacillus plantarum,Including the production and secretion of plantaricin gene different expression in transcriptional level can be detected by qPCR technology.The technique were used to detect expression difference of plantaricin related genes under salt stress So as to reveal the changes of antibacterial effect on transcriptional levelLactobacillus plantarm YM-4-3 is cultured in MRS medium with 0%NaCl detecting the transcription leve of transport system(plnGHSTUVW),activator gene of bacteriocins(plnC)and bacteriocin genes(plnRL,plnJK,plnIEF)on 4.5 h,12 h,18 h and 27 h.All genes don't overepress Theconcentrated.supernatant of 10 folds extracted on 4.5 h,12h,18 h and 27 h show no antibacterial effect.On the MRS medium with variant salinity(1,2,3,4%NaCl),The transport system of Plantaricin(plnGHSTUVW),the activator gene for expression of Plantaricin(plnC)and Plantaricin genes(plnRL,plnJK,plnIEF)are induced byNaCl,the expression are generally raised.and showing the maximum expression level in 27 h.The concentrated supernatant of 10 folds at 4.5 h,12 h,18 h and 27 h on the MRS medium are extracted.Data show the higher concentration of NaCl and longer culture time result in better antibacterial effect on Lactobacillus casei AS02 and Lactobacillus plantarum S11.However,supernatant without concentratingdon't show antibacterial effect on any indicator bacteria.