EVALUATION OF GENETIC DIVERSITY WITHIN XYLELLA FASTIDIOSA STRAINS ACROSS TEXAS

• Author(s): Mathews, Marlin; Morano, Lisa; Tsanova, Borislava;
• Abstract: Strains of Xylella fastidiosa have been isolated from infected grapevines and the vegetation surrounding vineyards. The gyraseB gene has been sequenced for approximately 20 strains and most of the strains fall into one of two categories, the grape group and the mulberry/ragweed group. Strains isolated from grape typically matched grape strains in the database and strains isolated from weeds and trees around vineyards closely matched the mulberry/ragweed sequences. However, one isolate from an infected grapevine was found to be a mulberry/ragweed strain suggesting that strains typically found in weeds can move into nearby grapevines. Due to the highly conserved nature of the gyraseB gene within strains we are also evaluating our cultures by PCR amplicon size for several small subunit repeats as suggested by Dr. Lin of USDA, ARS in California. This method creates a DNA fingerprint of each strain. Using this technique we are able to demonstrate that there are multiple mulberry/ragweed strains and multiple grape strains across Texas. We hope to combine these fingerprints with information about strain location to better understand the epidemiology of disease spread into newly infected vineyards. With fingerprint information on strains we also hope to create a phylogenetic tree of Texas strains to combine with similar data in other states allowing us to further understand the natural history and epidemiology of Pierces disease.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium