ARS | Publication request: Extracellular Xylella fastidiosa genomic DNA enhances biofilm formation in vitro

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 10, 2010
Publication Date: June 1, 2010
Citation: Lin, H., Cheng, D.W., Civerolo, E.L. 2010. Extracellular Xylella fastidiosa genomic DNA enhances biofilm formation in vitro. Phytopathology. 100:S72.

Technical Abstract: Xylella fastidiosa (Xf) is a Gram negative, xylem-limited bacterium that causes Pierce’s Disease (PD) of grapevine, as well as other diseases of economically important crops and landscape plants. Many bacteria produce large amounts of extracellular DNA, which may function as a matrix component in biofilms. Biofilm formation is essential for Xf establishment in planta. However, factors affecting Xf biofilm biogenesis in planta are not completely understood. The objective of this study was to determine if extracellular genomic DNA is involved in the Xf biofilm formation in vitro. The relative amounts of extracellular DNA were positively correlated with planktonic growth and biofilm formation in vitro, but were negatively correlated with cell viability. DNase I treatment of actively growing Xf cultures in culture medium decreased or inhibited biofilm formation. In contrast, addition of Xf genomic DNA promoted biofilm formation. These results suggest that biogenesis of extracellular DNA may play a role for Xf biofilm formation and could be a critical step in establishment of host-bacterium interaction.