ARS | Publication request: Grapevines undergo varying shifts in secondary metabolic profiles when infected with Xylella fastidiosa

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 14, 2012
Publication Date: July 1, 2012
Citation: Wallis, C.M., Chen, J. 2012. Grapevines undergo varying shifts in secondary metabolic profiles when infected with Xylella fastidiosa. Phytopathology. 102:S4.129.

Technical Abstract: Pierce’s disease (PD) is a devastating disease of grapevine caused by the bacterial pathogen Xylella fastidiosa (Xf). Key to the development and optimization of PD-tolerant grape cultivars is improved understanding about how grapevines defend themselves against Xf. This study complements histological and molecular genetic studies by observing shifts in host metabolic profiles that occur when grapevines are infected with Xf. Infected grapevines initially possessed increased levels of specific defense-associated phenolic compounds in xylem sap, pulverized tissues, and cell walls. Of particular interest were observed increases in procyanidin and stilbenoid content, as both of these secondary metabolite classes were previously associated with grapevine tolerance to other pathogen infections. However, infected grapevines ceased to possess greater levels of these defense-related metabolites upon onset of PD symptoms. Furthermore, in some cases PD symptomatic plants had lower phenolic levels than non-infected controls. It is hypothesized that when infected plants lose a great amount of green foliage due to PD, grapevines no longer have resources to produce secondary metabolites.