Research Of Virome In Chronic Periodontitis Patients By Viral Metagenomics And Primary Study Of Novel Viruses

Periodontitis is a common,multifactorial,chronic oral disease that has become a major disease affecting the health of residents in China.The causative agents of periodontal disease are generally thought to be periopathogenic bacteria,but the pure bacterial pathogenicity theory cannot cover all of the manifestations of periodontal diseases.Increasing evidence also support the role of virus other than bacteria in the pathogenesis of periodontal disease.Nevertheless,due to technical limits,the composition of the viral community in the periodontal environment and its association with periodontal diseases are still poorly understood.Nowadays,metagenomics technology provides technical support for the diagnosis of diseases and the exploration of potential pathogens.Viral metagenomics can be a powerful tool to understand the virome of periodontal disease and to explore novel viruses information.To investigate the virus makeup of periodontal community,we applied an unbiased viral metagenomics method,high throughput sequencing technology and bio-informatics to characterize the periodontal virome.Biopsy specimens were periodontal pockets or the gingival epithelium and connective tissue facing the sulcus from chronic periodontitis patients and periodontal healthy subjects.51 virus families from 24 samples were described.Most of the virus sequences were aligned to DNA viruses in periodontal environment,including double stranded DNA viruses and single stranded DNA viruses.Siphoviridae etc.are major components of virome in periodontal environment.We compared the differences between chronic periodontitis and healthy periodontal virome,which revealed the abundance distribution of viruses was higher in chronic periodontitis group and the diversity of viruses was higher in healthy group.There were similarities and differences between the virome of two groups.We also excavated two novel Betatorqueviruses and one novel siphovirus.The genome was obtained by inverse polymerase chain reaction and sequence assembly.The new isolates were named TTMV-222?TTMV-204 and Siphoviridae?29632,respectively.Structure analysis,phylogenetic analysis and sequence similarity analysis of three viruses were then conducted,and we established the detection methods of them.Subsequently,we investigated the relationships of three novel viruses and chronic periodontitis through three case control studies by principles and methods of molecular epidemiological survey.Results revealed that the detection of TTMV-222 and Siphoviridae?29632 may be associated with chronic periodontitis,while TTMV-204 showed no correlation.In this study,we revealed the virome in periodontal environment for the first time,excavated three novel viruses and investigated the association of novel viruses with chronic periodontitis.The present study demonstrated the effectiveness of viral metagenomics for the discovery of emerging viruses in the periodontal environment,providing new evidence to implicate viruses in periodontal diseases and offering new theoretical basis for the diagnosing,treatment and prevention of periodontal diseases.