ANALYSIS OF XYLELLA FASTIDIOSA TRANSPOSON MUTANTS AND DEVELOPMENT OF AN EN PLANTA XYLELLA FASTIDIOSA PLASMID VECTOR

• Author(s): Kirkpatrick, Bruce; Guilhabert, Magalie;
• Abstract: We have developed an autonomously replicating Xylella fastidiosa (Xf)/E. coli plasmid that efficiently transforms Xf; unfortunately this plasmid was not stably maintained in Xf cells en planta or without antibiotic selection in vitro. Another plasmid, containing an Xf native plasmid, a Kan(R) cassette and cloned in pUC18 was also constructed and shown to be unstable without antibiotic selection. 1000 random Tn5 mutants were again screened for virulence in grapevines growing in the greenhouse. An expectedly high percentage (35%) did not develop typical pierces disease (PD) symptoms; the insertion sites of the Tn5 in these apparently avirulent mutants are being sequenced. Approximately 3% of the random mutants were hypervirulent as compared to the wild type parental strain. Insertion sites of Tn5 in these mutants showed 2 were in putative LPS genes and 1 was in a hemagglutinin-like gene. The phenotype of these putative hypervirulent mutants is being confirmed in a second round of grapevine inoculations.
• Publication Date: Aug 2003
• Journal: 2003 Pierce's Disease Research Symposium