Transcriptomic Responses to Coaggregation between Streptococcus gordonii and Streptococcus oralis.

Area of Science:

• Microbiology
• Oral Biology
• Molecular Biology

Background:

• Cell-cell adhesion in oral bacteria is vital for forming polymicrobial communities like dental plaque.
• Oral streptococci, including Streptococcus gordonii and Streptococcus oralis, are early colonizers that aggregate with various oral microbes.
• Streptococcus gordonii exhibits active gene expression regulation in response to coaggregation.

Purpose of the Study:

• To investigate gene regulation in Streptococcus gordonii and Streptococcus oralis following coaggregation in human saliva.
• To compare the gene expression responses of S. gordonii when coaggregating with S. oralis versus other oral bacteria.

Main Methods:

• Coaggregation of S. gordonii and S. oralis was induced in 25% human saliva.
• RNA was extracted from coaggregates after 30 minutes for dual transcriptome sequencing (RNA-Seq).
• Comparative analysis of gene regulation patterns across different S. gordonii pairings was performed.

Main Results:

• In S. oralis, 18 genes were regulated (6 upregulated, 12 downregulated), affecting functions like amino acid biosynthesis and metabolism.
• In S. gordonii, 28 genes were differentially regulated (25 upregulated, 3 downregulated), including transporters and the NisK/SpaK two-component system.
• Gene regulation in S. gordonii was specific to the coaggregating partner, with responses differing between S. oralis, Fusobacterium nucleatum, and Veillonella parvula pairings.

Conclusions:

• Coaggregation triggers distinct gene expression profiles in oral streptococci.
• The specific gene regulatory responses of S. gordonii suggest an ability to differentiate between bacterial neighbors.
• This bacterial recognition is likely important for S. gordonii's adaptation during dental plaque biofilm development.