| Objective:To study the oral microbial community structure in caries-active and caries-free objects in Dongxiang and Han nationality using Illumina Miseq high-throughput sequencing, and analyze the "core microbes" and the microbes associated with caries and nationality. In order to analyze the real cause of tooth decay to privide the corresponding prevention and treatment measures to reduce the incidence of caries, so as to improve people’s quality of life.Methods:Based on Illumina Miseq high-throughput sequencing method,28 cases in Dongxiang and Han nationality in Gansu were choosed as the research objects(14 caries and 14 caries-free), saliva DNA were extracted and PCR amplification. Using Illumina Miseq sequencing platform, two-terminal sequencing of V4 areas of 16S rRNA was carried; Diversity of community structure was analyzed using the software such as Mothur, MEGAN4, Cluster 3.0 and Java Treeview software.Result:(1). A total of 252,157 high-quality sequences were obtained from 20 high-quality samples, the average length of read was 225 bp, the average depth of sequencing was 12,608 reads per sample.(2).12,751 OTUs and 2,795 species were found in 20 samples, belonging to 28 phyla,319 genera; A total of 7,013 OTUs (DC:4,544 OTUs, DH:2,469 OTUs) were detected in Dongxiang saliva samples, belonging to 26 phyla (DC:25, DH:23),250 genera (DC:219 OTUs, DH:153 OTUs); A total of 5,738 OTUs (HC:2,751 OTUs, HH:2,987 OTUs) were detected in Han saliva samples, belonging to 28 phyla (HC:25, HH:23),218 genera (HC:171, HH:176).(3). The Chao/Ace was greater than 0.5 in this study, Simpson index was less than 0.2, Shannon index was greater than 2.5, and the Coverage was greater than 0.94. The samples had the similar diversity index in 4 groups.(4). Principal component analysis(PCA) showed there were components concentration but had intersection in 4 groups.(5). There were 17 significant genera between DC and HC. In the dominant genera, Actinomyces, Leptotrichias, and Corynebacterium in DC were lower than that in HC group; There were 5 significant genera between DH and HH. In the dominant genera, Actinobacillus in DH were higher than that in HH group; There were 16 significant genera between DH and DC. In the dominant genera, Neisseria in DH were higher than that in DC group, Leptotrichias were lower than that in DC group; There were 4 significant genera between HH and HC. In the dominant genera, Rothia in HH were higher than that in HC group.(6). Core microbe analysis showed that there were 35 genera with the proportion of sequence more than 1%, Neisseria, Actinomyces, Actinobacillus, Streptococcus, and Leptotrichias were presented in 10 caries-active samples; There were 18 genera with the proportion of sequence more than 1%, Neisseria, Actinomyces, Actinobacillus, Streptococcus, Gemella and Leptotrichias were presented in 10 caries-free samples.Conclusion:We analyzed the relationship between saliva microorganisms with the development of caries in Dongxiang and Han from the macro microflora perspective. (1) The microbial community structure in saliva were complicated once again; (2) Compared to the former analysis methods, the biological information gained by Illumina Miseq high-throughput sequencing to analyze oral microbiota was very high and more bacteria associated with caries were found; (3) The shared organismal features demonstrated the existence of oral core microbes; (4) There were some discrepancies between DC, HC, DH, and HH group at the phylum and genus level, the variety in caries-active was lower than that in caries-free group; The existence of some genera had a negative correlation with caries, otherwise some genera had a positive correlation with caries; (5) Microbial community structure exist a certain differences between ethnic groups, but compared to the environmental factors, the difference caused by this factor was small. |
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