Sequencing Of Lactobacillus Paracasei L1 Genomics And Study On Functional Genes That Have Metabolism On Starch

In the early stage,the research group isolated a strain of Lactobacillus paracasei L1 that has a flocculating effect on starch granules from naturally fermented sweet potato physalis.Lactobacillus paracasei L1 can specifically bind to the surface of starch granules and condense the starch granules together into Large starch clusters,in turn,accelerate the sedimentation of starch.In the process of L1 flocculation and sedimentation of starch,the apparent structure and physical and chemical properties of starch have also changed.Therefore,the purpose of L1 adsorption on the surface of starch particles was guessed.Through previous experiments,it was found that L1 happened to be starch hydrolyzing lactic acid bacteria ALAB(Amylolytic Lactic Acid Bacteria),and found The proteins that bind to starch are 6-phosphate glucose isomerase,glycogen synthase,enolase,D-3-phosphoglycerate dehydrogenase,adenylate succinate synthase,triose phosphate isomerase Enzymes,elongation factor Tu,etc.confirmed that Lactobacillus paracasei L1 has the ability to utilize raw starch at the molecular level.In order to specifically ascertain the key genes of hydrolases related to starch and other polysaccharides in Lactobacillus paracasei L1 at the genetic level,analyze the specific metabolic pathways of starch,and use genomics to determine the complete genome sequence of Lactobacillus paracasei L1.Draw its gene map and use bioinformatics technology to annotate the genome of Lactobacillus paracasei L1,find important genes related to starch metabolism,and use the CAZY database to find glycoside hydrolase families.1?Complete genome sequencing of Lactobacillus paracasei L1.The genome is predicted and annotated.The basic information of the genome is analyzed.The results of the analysis are as follows: The basic information of the L1 genome of Lactobacillus paracasei shows that Lactobacillus paracasei L1 has a circular chromosome with a size of 3,121,955 bp and an average GC The content was 46.14%.The analysis yielded 3462 CDSs(number of genes),of which 3088 CDSs were located on chromosomes and 374 CDSs were located on plasmids.Both chromosomes and plasmids were circular molecules.There are 9 plasmids with sizes of74,549 bp,65,798 bp,53,066 bp,43,201 bp,32,566 bp,17,723 bp,10,420 bp,9,833 bp,4,936 bp,60 t RNAs containing almost all types of amino acid substrates,and 15 RNAs.GO and COG databases performed functional annotations on Lactobacillus paracasei L1,and found that the genome of L1 encodes a large number of functional genes related to membrane transport and carbohydrate metabolism,and 8 genes related to ?-amylase were found in COG0366(L1_gene0504,L1_gene0609,L1_gene0983,L1_gene0984,L1_gene2095,L1_gene2174,L1_gene2904,L1_p A_gene0058),it is speculated that Lactobacillus paracasei L1 has the ability to metabolize starch;2?The L1 genome encodes the enzymes necessary for the metabolic pathways of glycolysis,fructose,sucrose,and starch,confirming the ability of L1 to metabolize starch.And there are42 glycosidic bond hydrolases in the genome code of Lactobacillus paracasei L1,9 of which belong to the GH13 family of starch hydrolases,which mainly catalyze the cleavage of oligosaccharides or glycans linked by ?-1,4-glycosidic bonds.Such as ?-glucosidase mal Z,oligoglucose hydrolase mal Z,?-amylase amy A and ?-1,4-glucan branched chain enzyme glg B and so on.These enzymes are importantly related to the use of a variety of oligosaccharides and glycans linked by ?/?-glycosidic bonds by Lactobacillus paracasei L1,which is an important reason for its adaptation to plant substrates;3 ? The comparison result of the Carbohydrate Active Enzyme Database(CAZy,http://www.cazy.org/)shows that Lactobacillus paracasei L1 has a total of 105 CAZyme coding genes,of which 42 are glycoside hydrolases(GHs),accounting for all of them.40% of the coding genes,followed by glycosyltransferases(GTs),39 accounted for 37.14% of all coding genes,carbohydrate esterases(CEs),16 accounted for 15.24% of all coding genes,and auxiliary oxidoreductases(AAs)7 One accounted for 6.67% of all coding genes,and one carbohydrate binding module(CBMs)accounted for 0.95% of all coding genes.The number of glycoside hydrolases and glycosyltransferases determines the key to the cleavage of polymerized substrates.The genome encodes 42 GH glycoside hydrolase families,of which 9 GH13 starch hydrolase families are encoded.These 9 GH13 starch hydrolase families are divided into 5different subfamilies,namely GH13₃1,GH13₂9,GH13₂0,GH13₉,GH13₃6 family,the main task is to hydrolyze polysaccharides linked by ?-glycosidic bonds,which can hydrolyze starch and dextrin into reducing sugars such as glucose or maltose;it has also been found that the genome encodes 4 lysozymes(Lysozyme)in the database as GH25,lysozyme is mainly related to phage genes,mainly for cell autolysis.