PRESSURE CHAMBER EXTRACTION OF XYLEM FLUID: IMPROVING BACTERIAL DETECTION IN PLANTS AFFECTED BY XYLELLA FASTIDIOSA

• Author(s): Bextine, Blake; Miller, Thomas;
• Abstract: Xylella fastidiosa is the xylem-limited bacterium that causes Pierces disease of grapevine and oleander leaf scorch. 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 the study reported here, we directly compared X. fastidiosa detection in whole-tissue samples to xylem fluid samples from grapevine and oleander. Collection of 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%). There were no differences in frequency of detection of X. fastidiosa in symptomatic grapevines by ELISA or PCR dependent upon sample collection method. Assays of xylem fluid samples did not improve detection of X. fastidiosa in symptomatic or asymptomatic oleander compared to assays of whole tissue. Finally, in a direct comparison of ELISA and PCR, we found no significant differences in frequencies of positive grapevine or oleander samples detected.
• Publication Date: Aug 2003
• Journal: 2003 Pierce's Disease Research Symposium