ROLE OF UNIQUE GENES OF XYLELLA FASTIDIOSA GRAPE STRAIN IN HOST SPECIFICITY AND VIRULENCE TO GRAPE AND TO INSECT USING MICROARRAY

• Author(s): Lindow, Steven; Feil, William;
• Abstract: Xylella fastidiosa (Xf) is a group of genetically similar strains that infect a wide range of plants. We hypothesized that differing genetic factors among the strains determine the ability of a strain to infect a particular host plant. To better understand what makes grape a good host for all grape strains but not for strains such as oleander and almond that cannot colonize grape, we conducted experiments to look for host specific genes of the grape strain. Through our microarray and in silico genomic studies, we have so far identified 52 potential Xf grape strain virulence genes. We have constructs for knocking out 12 of the 52 identified genes. The genes we chose from our list were greater than 300 bp and were not part of a remnant phage. Our constructs have a Kanamycin gene inserted near the 5 end of the gene for optimum efficiency in knocking out our gene and preventing Xf from making partial transcripts. We plan to inoculate plants with our knock-out mutants once they are confirmed. We noticed that the microarray studies have produced fewer genes than expected, indicating that the similarity between Xf Temecula and other non-grape strains must be greater than expected. Our in silico comparisons revealed a high level of similarity as well. Because of this, we are now using dual labeling with our microarray studies. This is a more sensitive way to identify differences in gene sequence between the strains.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium