EVALUATION OF SINGLE NUCLEOTIDE POLYMORPHISMS AND SAMPLE PREPARATION PROCEDURES IN THE DETECTION OF XYLELLA FASTIDIOSA STRAINS IMPORTANT TO CALIFORNIA

• Author(s): Chen, Jianchi; Civerolo, Ed;
• Abstract: The main objective of this project is to develop a PCR-microarray-based system for accurate and quick identification of Xylella fastidiosa (Xf) strains important to California crops. The major part of the current work focused on identification of important DNA sequences based on single nucleotide polymorphisms (SNPs) for the detection of Xf Pierces disease (PD) and almond leaf scorch disease strains. We expanded the previous SNP analysis in 16S rDNA to other house-keep genes, such as those coding for TCA cycle enzymes. Xf-specific primers were designed and real-time PCR was employed. Melting point analysis was used to confirm the presence of SNPs in the amplicons and to detect different genotypic strains. A second effort was to develop and improved procedure of sample preparation, the bottleneck of PCR detection of Xf in planta. We developed two simple sample preparation procedures for PCR amplification of Xf DNA from infected almond and grape petioles using freshly squeezed petiole sap and freeze-dried tissue. The detection efficiency of the two PCR methods was similar to that of the pathogen isolation procedure.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium