The Relationship Between H-serotype And Flagellar Encoding Genes In Bacillus Thuringiensis

1 Relationship between H-serotype and flagellar synthetic gene cluster of BtBacillus thuringiensis abbreviated Bt.Cry protein producted by Bt have a specific toxic activity to specific one or more insects,so Bt is bio-control bacteria with wide applications and unlimited potential.The method of identification and classification of Bt is based on Cry protein.But genes encoding Cry protein is located in plasmids and easy to transfer or loss and difficult to identify Bt which silencing the expression of cry gene.In the 1960s,flagellar serotype began to used for the classification and identification of Bt.Flagellar serotype is related to the diversity of the flagellin.Researching flagellar serotype from the perspective of gene sequence diversity can fill the blind spots.This study based on whole genome sequences of the 130 Bt strains,flagellar synthetic gene cluster is widespread in 130 Bt strains.1)No correlation between the ORF structure and copy number of hag and H-serotypeThe differences of ORP structure in Bt was not being concerned.So according to the differences of ORF distribution,flagellar synthetic gene clusters can be divided into 13 types.Type b and type f accounted for more than 60%and 10%.The differences of copy number of hag gene still exist.The copy number of hag gene was from 1 to 6 and strains with 2 hag genes accounted for more than 60%.As a result,ORF distribution and the copy number of hag gene can not reflect the diversity of flagellar serotype.2)These genes can distinct strains with different serotype in different degreeComparing sequence of flagellar synthetic gene clusters,found that flgK,flgL,fliD and hag have obvious differences.In addition,hag gene can divided into hag1 and hag2 according to similarity.Analysis diversity of these genes and flgG,flgD,found that these genes can distincted strains with different serotype in different degree,especially hag2 and fliD.So fliD gene can add hag2 in classification of flagellar serotype.Therefore,figK,flgD,flgL,fliD,flgG,flgE,hag1,hag2 can distinct Bt strains with different serotype in different degrees.3)The diversity of hag2 and JliD could most reflect the diversity of H-serotypeThe pr:imary structure of FliD is conservative on both ends and variable on middle part,the same as flagellin encoded by hag.Analysis phylogenetic trees based on fliD and hag2 using ML,then found that JliD and hag2 can separate most of Bt strains with different serotype.In addition,fliD makes more different H-serotype strains be distinguished and add hag2.4)Differences of expression are a factor to influence the flagellar serotypeFinally analysis the genes encoding flagella extracellular structural protein from expression level.These genes in Bt strains with different serotype have different expression,so differences of expression is a factor to influence the flagellar serotype.2 The function of Bacteroides and Prevotella core genomesThere are abundant microbial groups in the intestinal tract,carrying the genome that is about 150 times of the human genome.So microbial groups in the intestinal tract were called "the second genome" of human.According to the abundance of intestinal microflora and function analysis,we divided the human gut microbiome into three enterotypes.There are Bacteroides(enterotype I),Prevotella(enterotype II)and Ruminococcus(enterotype III).Individual diet with enterotype I tend to plant,but Individual diet with enterotype II tend to meat.1)Bacteroides genus have common potential to live in gut,but parasitic sites ofPrevotella genus have specificityBacteroides genus has 39 strains and Prevotella genus has 46 strains.Comparing genome size and GC%of Bacteroides genus and Prevotella genus,Bacteroides own larger genome size and bigger range than Prevotella.But GC content of two genus is similar.Open analysis shows that the genome of Bacteroides is closed,but it was reported that the genome of Prevotella genus is open.Based on single core genes of Bacteroides and Prevotella,build ML phylogenetic tree and found that Bacteroides genus have common potential to live in gut,but parasitic sites of Prevotella genus have specificity.2)The core genome of Bacteroides tend to metabolize material of plant but the coregenome of Prevotella tend to metabolize material of animal We get COG annotation,CAZymes annotations and MEROPS annotations of core genomes of Bacteroides and Prevotella,then statistics and analysis these datas.CAZymes annotation show that GH2 and GH3 which metabolize cellulose and hemicellulose,CE6 which metabolize xylan and CBM57 which adhere to lactose and galactose have significantly higher proportion in core genome of Bacteroides than that in core genome of Prevotella.However,GH25 and GH13 which metabolize peptidoglycan and transport amino acids,CE10 which metabolize aromatic ester,CBM20 which adhere to granular starch and CBM48 which adhere to glycogen have significantly higher proportion in core genome of Prevotella than that in core genome of Bacteroides.From the analysis of MEROPS annotations,S protease and M14B of M protease in core genome of Bacteroides is much greater than that in Prevotella;On the contrary,M41 in core genome of Prevotella is much greater than that in Bacteroides.In conclusion,In intestinal tract of individual whose diet tends to be a vegetarian,polysaccharides such as cellulose are rich,so the surroundings are suitable for strains of Bacteroides genus and form enterotype I.In intestinal tract of individual whose diet tends to meat,animal protein are rich,so the surroundings are suitable for strains of Prevotella genus and form enterotype Ⅱ.