Identification And Whole Genome Sequence Research Of The Ant Symbiotic Actinomycete Streptomyces Capitiformicae Sp.nov.

Due to the slow development of new antibiotics in recent years,people gradually found insect endophytes can produce a large number of active secondary metabolites.In particular,the bacterial strains which show the obvious antagonism activity against pathogenic fungi,bacteria,etc.,have much more opportunities to isolate antibiotics than inactive strains.The new species of Streptomyces which defined from the modern taxonomic sense are also the main source of new antibiotics and highly effective antimicrobials.The compounds isolated from microbes associated with insect are generally harmless to the insects themselves,Therefore,the toxicity of this type antibiotic is much safer than the other isolates,such antibiotics can also be safely used in plants and animals.It is precisely because insects endophytic actinomycetes can produce human medicinal potential of antibiotics,symbiotic actinomycetes in the insects received more attention in recent years from many scientists,insect endogenous actinomycetes also will be one of the important area to discover new antibiotics,which have a great of significance against the increasing drug-resistance bacteria and new disease.This research selected strain 1H-SSA4 as material,16S rRNA sequencing analysis results showed that the strain 1H-SSA4 may be a new species of Streptomyces,IH-SSA4 and its four similar strains can form stable branch in the phylogenetic tree.Using the polyphasic taxonomy method to identify strain 1H-SSA4 by contrast these characteristic which including morphology characteric observation,physiological and biochemical analysis and chemical analysis.Then,through the whole genome analysis,the gene cluster of 1H-SSA4 was analyzed.Then the secondary metabolites were separated from 1H-SSA4,and all these structures were determined by the gene cluster of 1H-SSA4.Experimental results are as follows:(1)The 16S rRNA analysis results show that the strain 1H-SSA4 maybe a new strain of Streptomyces bacteria,and the four strains can form stable branch in the phylogenetic tree,Streptomyces hygroscopicus subsp.Ossamyceticus NBRC 13983~T(98.9%),Streptomyces torulosus LMG 20305~T(98.8%),Streptomyces ipomoeae NBRC 13050~T(98.5%),Streptomyces decoyicus NRRL 2666~T(98.4%).The spores form of strain 1H-SSA4 in line with the characteristics of Streptomyces,physiological and biochemical results compared with the similarity strain are differences,chemical taxonomic characteristics(whole cell hydrolyzed sugar,lipid phosphate,methylnaphthoquinone,fatty acids)are in accordance with the characteristics of Streptomyces.DNA-DNA relatiness results were less than 70%,indicating that the strain of 1H-SSA4 was significantly different in genetic composition than its similar strains.Therefore,1H-SSA4 was determined a new species of Streptomyces,which was named Streptomyces capitiformicae,and the typical strain was 1H-SSA4~T(=DSM 140537~T=CGMCC4.7403~T).(2)Through the study of the strain 1H-SSA4~T fermentation cultivation,the separation of secondary metabolites from the fermented product,using modern spectroscopy to identify the structural analysis,got three compounds 1H01?1H02 and 1H03,and the structure configurations of three compounds were determined.Compounds 1H01 and 1H02 are angucyclinone antibiotic 8-O-methyltetrangulol and 8-O-methyltetrangomycin,compound 1H03 are angucyclinone antibiotic fugianmycin B.Through the whole-genome sequencing technology,1H-SSA4~T have the gene cluster can be sure to produce angucyclinone antibiotic,and the analysis of residual gene cluster predicts that 1HSSA4~T would produce the core structure of other types of compounds.