A ConA-like lectin isolated from Canavalia maritima seeds alters the expression of genes related to virulence and biofilm formation in Streptococcus mutans

Bacteria form biofilms as an adaptive mechanism in response to environmental changes. Streptococcus mutans is the biofilm-forming bacterium that is primarily associated with dental caries. The expression of important genes by bacteria in biofilms is different from that of planktonic cells. Lectins are proteins that bind specifically to carbohydrates and may have important biological activities on bacterial cells, acting as antibacterial and anti-biofilm agents. ConM (Canavalia maritima lectin) is a protein that is able to inhibit the planktonic growth and biofilm formation of S. mutans. In this context, this study aimed to evaluate the effects of ConM and concanavalin A (ConA) on the expression of genes related to virulence and biofilm formation in S. mutans. The results showed that ConM significantly reduced the expression of genes encoding enzymes related to adhesion, formation and regulation of biofilms. On the contrary, ConA did not alter the expression of the genes studied. Because the two lectins have a high degree of similarity, the differences in the actions of ConM and ConA may be explained by the small structural differences in the carbohydrate recognition domain of the lectins.