| Xylella fastidiosa is a plant pathogen which causes leaf scorch diseases such as, Oleander Leaf Scorch, Plum Leaf Scald, and Pierce's Disease (PD) of grapevine. These diseases are caused by three subspecies of the bacteria inhabiting the xylem of plants and mouthparts of the insect vectors. Early phylogenetic analysis of bacteria isolated from symptomatic hosts and vectors suggested that only one subspecies of X. fastidiosa was able to effectively colonize grapevines. Genetic diversity of X. fastidiosa was assessed by a 13-gene assay on bacteria cultured from plant and insect samples collected in the Stephenville area. A profile was developed for 30 isolates showing possible recombination between subspecies. Bacteria isolated from two symptomatic grapes showed similarity to subspecies multiplex. The genetic diversity seen in the X. fastidiosa isolates indicates the need for a more expansive screening of the genome to determine if recombination between subspecies plays a role in pathogenicity. |
