Alejandro Cabezas-Cruz | INRA
Ixodes scapularis ticks harbor microbial communities including pathogenic and non-pathogenic microbes. Pathogen infection increases the expression of several tick gut genes, which disturb the tick gut microbiota and impact bacterial biofilm formation. Here, we tested the resistance (insensitivity to disturbance) of tick microbiota and tick microbiome to pathogen infection, antimicrobial peptides and anti-tick immunity. We demonstrated that Anaplasma phagocytophilum infection and the tick antimicrobial peptide IAFGP have small impact on the taxonomic and functional traits of tick microbiota. In contrast to pathogen infection and antimicrobial peptide, host immunity specific to the tick protein PIXR disturb dramatically the tick microbiota and the composition and abundance of metabolic pathways in the I. scapularis metagenome. Anti-tick immunity increases the representation and importance of polysaccharide and siderophore biosynthesis pathways involved in biofilm formation while these pathways are under-represented in the gut microbiome of ticks infected by A. phagocytophilum or exposed to IAFGP. These analysis reveal that tick microbiota in highly sensitive to anti-tick immunity and resistant to pathogen infection and antimicrobial peptides. The formation of dense biofilms due to increase in biofilm formers may be part of a protective response of tick microbiota to anti-tick immunity. This raises an interesting question; can anti-tick vaccination trigger the formation of biofilms that increase the resistance of ticks to anti-tick vaccines?
Host: Ana Domingos, Sandra Antunes
