EFFECTS OF CHEMICAL MILIEU ON ATTACHMENT, AGGREGATION, BIOFILM FORMATION, AND VECTOR TRANSMISSION OF XYLELLA FASTIDIOSA STRAINS

• Author(s): Purcell, Alexander; Burr, Thomas; Curley, Clytia; Hoch, Harvey; Lindow, Steven;
• Abstract: We have measured in vitro survival, growth and biofilm formation of wild-type and mutant strains of Xylella fastidiosa (Xf) under a variety of conditions. The mutant strains are deficient in their production of the signaling molecule DSF. The role of DSF in biofilm formation is not clear, but these strains cannot attach and/or form biofilms in insect mouthparts (strains KLN 61 or 62, rpfF-mutant; Newman et al. 2004). Our attachment studies of these strains indicate that the DSF-deficient strain is also less proficient at biofilm formation in vitro compared to the gfp-Temecula strain. Population studies of wild-type and mutant strains grown separately or together show similar patterns of growth, and no evident competition between strains in vitro for up to 14 days. Complementary in vivo studies in our laboratory are looking at both strain competition and transmissibility of wild-type and mutant strains of Xf co-inoculated into grapevines. In order to more closely approximate conditions in the insect mouth, we have also assayed attachment of gfp-Temecula or wild-type Temecula strain on sterile insect wings, which have a cuticular surface like the interior of the mouthparts to which Xf attaches. We have so far not observed bacterial attachment to wings that were incubated in PW broth or in a media deemed more optimal for in vitro biofilm formation in preliminary studies. Insect mouthparts and wings (from glassy-winged sharpshooter (GWSS)) are also being investigated as an attachment surface in flow chambers by our collaborators at Cornell University.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium