Diversity Of Endophytic Bacteira From Populus Euphratica In Ancient River Ugen And Taxonomic Identification Of A Novel Bacterium Rhizobium Tograkense

The aim of this study was to evaluate the Phylogenetic diversity and communitystructure of the culturable endophytic bacteria in the Populus euphratica stand at the middlereach of the ancient Ugan rivers.265cultivable strains were isolated from the liquid sampleby using5different medium （LB,NA,MA,TSA and KingA）. In order to determine thebacterial diversity and the identity of Endophytic Bacteria from the Populus euphratica,weperformed a phylogenetic analysis of the16S rDNA sequencing data of265phenotypicallydifferent isolates, they have been placed into5phylogenetic groups Firmicutes （43.78%）,Gamma Proteobacteria （39.25%）, Acinetobacter （13.96%）, Alpha-Proteobacteria（2.26%），Beata-proteobacteria（0.3%） and Bacteroidete（0.3%）,32genera and66species,in which including9gene,18species with16S rDNA similarity values <98%, thatcould possibly represent new species. Among them, the genera Bacillus and Pseudomonaswere the most widely distributed and predominant, occupied the majority of the total isolates23.01%and21.89%, respectively. The dominance index of three cultural mediumdemonstrate that the isolates of LB medium had higher bacterial diversity.Strains K-38Gram-negative, catalase and oxidase-positive, rod-shapedbacterium isolate from Populus euphratica in Ugen ancient river. were characterized, using apolyphasic taxonomic approach. Studies based on comparative16S rRNA gene sequenceanalysis showed that that Strains K-38belonged to the genus Rhizobium, showing the highestsequence similarities to Rhizobium rosettiformans（96.81%）, Rhizobium neptum（96.43%）and Rhizobium borbor（i96.03%）.DNA–DNA reassociation values between the Strains K-38Tand type strains of the most closely related Rhizobium rosettiformans exhibited less than48.4%similarity. The G+C content of the genomic DNA was63.5mol%. Summed Feature8（56.1%）, C16:0（13.94%）and Summed Feature2（11.45%）the predominant fatty acids.The polar lipid profile of strain K-38Tconsisted of phosphatidylethanolamine, unknownaminolipids APL1and APL2, phospholipid PL1. The novel isolates were differentiated fromrelated Rhizobium species by physiological and biochemical tests. On the basis of the evidence from this polyphasic study, it is proposed that the isolates from the Populuseuphratica be classified as a new species of the genus Rhizobium, RhizobiumTograkense sp.nov.