Characterization of Streptococcus thermophilus two-component systems: In silico analysis, functional analysis and expression of response regulator genes in pure or mixed culture with its yogurt partner, Lactobacillus delbrueckii subsp. bulgaricus

► The 8 response regulators (RR) of S. thermophilus LMD-9 are expressed in milk. ► The S. thermophilus LMD-9 RR present different expression profiles during growth. ► Mixed culture of S. thermophilus with L. bulgaricus results in over-expression of 4 rrs.