The role of the com system in eDNA uptake mediated by the Type IV pilus in Xanthomonas citri subsp. citri

DUNGER G.; JAIME CL.; SGRO G.; FARAH C.

Mendoza

Congreso; SAIB 2022; 2022

SAIB Argentina

Xanthomonas citri subsp citri is a bacterial phytopathogen that causes citrus canker disease, one of significant economic importance around the world. X. citri spreads from affected plants to healthy plants mainly through rain and wind and has the ability to survive for long periods on different surfaces usually due to the formation of biofilms. The bacterial biofilm is a highly regulated community of bacteria embedded in a polymer matrix composed of polysaccharides, proteins and extracellular DNA (eDNA) that provide physical support and protection against biotic and abiotic stresses. X. citri has been observed to produce a more robust mature biofilm in host plants than in non-host plants. Furthermore, the type IV pilus (T4P) plays an important role in the formation of biofilms, which highlights its importance in the bacterial life cycle. T4Ps are long, flexible filament located on the bacterial surface involved in a variety of important behaviours including twitching motility, surface adhesion, natural transformation, chemotaxis and biofilm formation. In some bacteria, T4P carry out the additional function of incorporating of eDNA into the cell by a mechanism coupled to the natural competence (com) system. In addition to the main components involved in T4P biogenesis and regulation, the X. citri genome also carries the com genes predicted to be involved in the internalization of exogenous DNA: comEA, comEC and comF. The main objective of this project is to investigate the interplay of the T4P, the com system and eDNA. Progress in this area will provide information of great interest for the understanding the phenomenon of T4P- and com-mediated eDNA uptake and signalling in biofilm formation and/or twitching motility; both mechanisms being involved in infection, horizontal gene transfer and bacterial dissemination andpersistence.