Characterization of saliva microbiota's functional feature based on metagenomic sequencing.

Fang Yang,Xiao Yuan,Qian Zhou,Xiaoquan Su,Kang Ning,Xiaowei Zeng

doi:10.1186/s40064-016-3728-6

Abstract

Objective Saliva, a mixture of exocrinally secretive fluids, amounts to ~1.5 L daily and harbors numerous microbial inhabitants. However, except the organismal structure of saliva microbiota, the functional profile of saliva microbiota remain elusive.MethodsHere we used metagenomic sequencing to experimentally reconstruct the global genomic profile of saliva by sequencing total saliva DNA from two healthy and two caries-active (DMFT ≧ 6) adults.ResultsWe found that saliva microbiota, representing 30–60% of total saliva DNA in our samples, might carry functional signatures that were site-specific and caries-state-specific. Among microbiota from different hosts, a prominent functional core, but not an organismal core, was identified. Each microbiota exhibited functional redundancy where dominant genomes tend to encode more functional diversity yet without necessarily contributing to dominant functions. Furthermore, genetic polymorphisms of hosts were also unraveled from salivary DNA without apparent physical or sequence bias in human chromosomes.ConclusionsThe microbial functional sensitivity to disease, links to specific functions, and permission of simultaneous genotyping of hosts and microbiota suggested sequencing salivary DNA might be an advantageous venue in uncovering both human and microbial basis of oral infections.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-3728-6) contains supplementary material, which is available to authorized users.

Highlights

Human body is the home to numerous symbiotic microbial organisms that with equal number of our own cells (Sender et al 2016; Sleator 2010)
Growing evidence from our research groups and others suggested that organismal structure of saliva microbiota is correlated with disease state such as caries (Yang et al 2012), gingivitis (Huang et al 2011) and periodontitis (Griffen et al 2011), the organismal structure of saliva microbiota can potentially serve as a proxy to the oral health of the host (Nasidze et al 2009; Kanasi et al 2010)
A core of 2203 functions derived from 33,487 gene sequences was identified (Fig. 1a)

Summary

Introduction

Human body is the home to numerous symbiotic microbial organisms that with equal number of our own cells (Sender et al 2016; Sleator 2010). They not just count upon the human body for food and shelter, and provide the host with metabolic functions far beyond our own physiological capabilities (Sleator 2010). Except the organismal structure of saliva microbiota, the functional profile of saliva microbiota remain elusive and it potential link to health and disease is not well understood (Human Microbiome Project Consortium 2012)

Methods

Results

Conclusion