Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: 10/7/2009
Publication Date: 12/9/2009
Citation: Lin, H., Cheng, D.W., Civerolo, E.L. 2009. Xylella fastidiosa Extracellular Genomic DNA May Play a Role For Enhancing Biofilm Formation In Vitro. In: CDFA Pierce's Disease Control Program Research Symposium, December 9-11, 2009, Sacramento, CA. p. 96-99.
Interpretive Summary: Extracellular DNA produced by Xylella fastidiosa (Xf) stimulates biofilm formation, which facilitates establishment of Xf infection in plants. Xf cell growth and biofilm formation in culture were positively correlated with extracellular DNA produced by Xf, but negatively correlated with Xf cell viability. Biofilm formation was decreased or inhibited when growing cells were treated with DNase I, an enzyme which degrades DNA. In contrast, addition of Xf genomic DNA to cultures promoted biofilm formation. These results suggest that biogenesis of extracellular DNA may play a role in Xf biofilm formation and, therefore, contribute to development of Pierce’s disease.
Technical Abstract: Xylella fastidiosa (Xf) produces extracellular DNA in PD3 liquid medium. This extracellular DNA may play a role in enhancing biofilm formation, a factor that is required by Xf to establish infection in host plants. Amounts of extracellular DNA generated by Xf in vitro were positively correlated with planktonic cell growth and biofilm formation, but were negatively correlated with cell viability. DNase I treatment of actively growing Xf cultures in PD3 medium resulted in decrease or inhibition of biofilm formation. In contrast, addition of Xf genomic DNA to Xf cultures promoted biofilm formation. These results support the hypothesis that biogenesis of extracellular DNA may play a role in Xf biofilm formation leading to successful host plant infection.