Identification And Genomic Characterization Analysis Of Three Novel Strains Of Luteimonas

As an important part of ecosystem,microorganisms play an important role in material circulation and energy flow.At present,less than 1%microorganisms of soils were known to cultivable,and even less is known about desert and saline soils.Our research group previously cultivated three strains of Luteimonas from desert and saline soils in Inner Mongolia,named SJ-16^T,SJ-9^T,and SJ-92^T,respectively.These strains had low 16S rRNA gene similarities to all current type strains.In this study,the three stains were identified using the polyphasic taxonomy method.In order to understand these three novel species,the genomic characteristics of single strains and the genus（Luteimonas）were analyzed.The results showed that the 16S rRNA gene sequence similarities between stains SJ-16^T,SJ-9^T,and SJ-92^Twere 96.6-98.4%.Strain SJ-16^Tshared the highest 16S rRNA sequence similarities with L.chenhongjianii 100111^T（98.8%）and L.terrae THG-MD21^T（98.6%）.Strain SJ-9^Tshared the highest 16S rRNA gene similarities with L.marina FR1330^T（97.9%）.Strains SJ-92^Tand L.aestuarii B9^Tshared the highest 16S rRNA gene similarities（98.4%）.Strains SJ-16^T,SJ-9^T,and SJ-92^Thad the highest ANIb values with the type strains L.chenhongjianii 100111^T,L.marina FR1330^Tand L.huabeiensis HB2^T,reaching 80.9%,84.4%,and 80.3%respectively,which were lower than the ANI threshold（95-96%）;Their had the highest d DDH values with the type strains L.terrae THG-MD21^T,L.marina FR1330^Tand L.huabeiensis HB2^T,reaching 37.5%,39.2%,and 26.4%respectively,which were also lower than the d DDH threshold（70%）.The major fatty acids of SJ-16^T,SJ-9^T,and SJ-92^Twere iso-C_15:0and Summed Feature 9(C_16:010-methyl and/or iso-C_17:1ω9c).The major polar lipids were diphosphatidylglycerol,phosphatidylglycerol and phosphatidylethanolamine.Strains SJ-16^T,SJ-9^Tand SJ-92^Twere identified as three novel strains of Luteimonas and named as Luteimonas deserti sp.nov.,（type strain SJ-16^T）,Luteimonas saliphila sp.nov.,（type strain SJ-9^T）and Luteimonas salinisoli sp.nov.,（type strain SJ-92^T）,respectively.The genomic analysis showed that the genomic DNA G+C contents and the genome size of SJ-16^T,SJ-9^Tand SJ-92^Twere 3.7,4.6,and 4.5 Mb,and 69.3,69.3,70.4 mol%,respectively.Genome analysis results show that they can be through the glycolytic pathway of glucose and fructose into acetyl-Co A and enter the TCA cycle,their genome mainly contain glucoside hydrolase and sugars such as glycosyl transferase activity enzyme,coding aryl polyene clusters and lasso peptides clusters and other secondary metabolites synthesis gene cluster.The three novel strains have improved their abilities to adapt to extreme environmental conditions by synthesizing contact enzymes to remove reactive oxygen molecules in time,synthesizing trehalose to balance osmotic pressure,using Hsp90 molecular chaperone to assist protein folding,and regulating gene transcription of strains through Crp system.Genomes contains some disease-related genes,which may create genomic tools for human to fight against diseases.All these provide a certain reference for better understanding of Luteimonas in the future.