Improved detection of Xylella fastidiosa in asymptomatic grapevine using xylem fluid collection technique

• Author(s): Bextine, Blake; Miller, Thomas;
• Abstract: Xylella fastidiosa (Xf) is the xylem-limited bacterium that causes Pierces disease of grapevine. Detection of this pathogen prior to symptom development is critical for improved management of the pathogen. ELISA and PCR are currently used for routine detection of the pathogen; however both detection methods are limited by low titer or patchy distribution of the bacterium within a host plant. In this study, we directly compared X. f. detection in whole-tissue samples to xylem fluid samples from grapevine and also oleander. DNA extraction from xylem fluid samples improved sensitivity of pathogen detection by ELISA (41.0%) compared to whole-tissue samples (20.5%) in asymptomatic grapevine. Additionally, pathogen detection in asymptomatic grapevine by PCR was also improved when xylem samples were tested (66.7%) compared to whole-tissue samples (23.1%). Detection in xylem fluid samples did not improve detection of X. f. in symptomatic or asymptomatic oleander. Finally, in a direct comparison of ELISA and PCR, we found no significant differences in numbers of positive grapevine or oleander samples detected.
• Publication Date: Jun 2003
• Journal: Phytopathology