Identification ofV. parvulaandS. gordoniiadhesins mediating co-aggregation and its impact on physiology and mixed biofilm structure

Abstract

ABSTRACTThe dental plaque is a polymicrobial community where biofilm formation and co-aggregation, the ability to bind to other bacteria, play a major role in the construction of an organized consortium. One of its prominent members is the anaerobic didermVeillonella parvula,considered as a bridging species, which growth depends on lactate produced by oralStreptococci. Understanding howV. parvulaco-aggregates and the impact of aggregation has long been hampered due to the lack of appropriate genetic tools. Here we studied co-aggregation of the naturally competent strainV. parvulaSKV38 with various oral bacteria and its effect on cell physiology. We show thatV. parvularequires different trimeric autotransporters of the type V secretion system to adhere to oralStreptococciandActinomyces. In addition, we describe a novel adhesin ofStreptococcus gordonii,VisA (SGO_2004), as the protein responsible for co-aggregation withV. parvula. Finally, we show that co-aggregation does not impact cell-cell communication, which is mainly driven by environmental sensing, but plays an important role in the architecture and species distribution within the biofilm.