Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 6/10/2007
Publication Date: 7/28/2007
Citation: Backus, E.A. 2007. Competitive Binding Influences Xylella fastidiosa Vector Load: Confocal and SEM images of GFP-expressing Xf in Glassy-Winged Sharpshooter Foreguts. American Phytopathological Society. 97:S6.
Technical Abstract: Introduction of the glassy-winged sharpshooter (GWSS) into California has caused an increase in incidence of Pierce’s Disease in grape-growing regions. Although host plant resistance to the causative bacterium, Xylella fastidiosa, and/or its GWSS vector is being sought, research is hampered by lack of understanding of the acquisition and inoculation process. X. fastidiosa (Xf) is acquired into and colonizes the anterior foregut of the vector (the precibarium and cibarium), and is somehow inoculated back into the plant from this area during the feeding process. To study the location of acquisition (from which inoculation occurs), we developed a confocal laser scanning microscopy method to visualize green fluorescent protein (GFP)-transformed Xf in situ within the undissected foregut of the vector. Fine structure of the colonies was then examined via scanning electron microscopy. We performed the first time course study of GFP-Xf acquisition by GWSS, across acquisition access periods ranging from 1 to 14 days. Bacterial colonies first form in the precibarium, then later accumulate in the cibarium. In addition, we also compared acquisition success by field-collected GWSS vs. lab-reared GWSS. Field- collected GWSS were able to acquire fewer Xf into critical areas of the precibarium than were lab-reared GWSS. Implications for inoculation of bacteria from these sites are discussed.