ARS | Publication request: Xylella fastidiosa infection of grapevines affects host secondary metabolite and defense-related protein levels within xylem

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2011
Publication Date: June 1, 2011
Citation: Wallis, C.M., Sisterson, M.S. 2011. Xylella fastidiosa infection of grapevines affects host secondary metabolite and defense-related protein levels within xylem. Phytopathology. 101:S185.

Technical Abstract: Pierce’s disease of grapevine is a serious threat to grape production and is caused by the xylem-dwelling bacterial pathogen Xylella fastidiosa. Microscopy studies have documented morphological changes to grapevine xylem due to infection by X. fastidiosa. Comparatively, less is known about the biochemical interactions between X. fastidiosa and grapevine. In this study, phenolic content of xylem sap collected from non-inoculated and X. fastidiosa-inoculated grapevine was assessed using high-performance liquid chromatography. In addition, peroxidase, polyphenol oxidase, exo-chitanase, and beta-glucanase levels of non-inoculated and X. fastidiosa-inoculated grapevine were compared using enzymatic activity assays. Greater levels of four phenolics, including resveratol, were observed in infected grapevine compared to uninfected grapevine. While beta-glucanase levels were reduced in infected grapevine compared to uninfected grapevine, effects of infection on other proteins was unclear. A better understanding of the role of phenolic compounds in grapevine defense against infection may aid in the development of novel management strategies. Likewise, documented shifts in compound levels could be used to develop detection methods for Pierce’s disease that are host-based as opposed to pathogen-based.