EVALUATION OF AN ANTIBACTERIAL PEPTIDE (CECROPIN A) AS A RESISTANCE AGENT IN PLANT XYLEM AGAINST XYLELLA FASTIDIOSA

• Author(s): Hammock, Bruce; Kamita, Shizuo; Warkentin, Donald;
• Abstract: Cecropin A (Gudmundsson, et al., 1991) is a bactericidal peptide that is a potential source of resistance against X. fastidiosa, the causal bacterium of Pierces disease. In vitro assays in our laboratory demonstrate that cecropin A is bactericidal against X. fastidiosa. We are utilizing the model plant, Arabidopsis thaliana, to evaluate the feasibility of using cecropin A expressed in transgenic plants as a resistance agent in plant xylem against Xylella fastidiosa. Because X. fastidiosa is a xylem-limited bacterium (Purcell and Hopkins, 1996; Hopkins, 1989), xylem-specific expression of cecropin A is required for effective resistance to Pierces disease. To achieve our ultimate goal of producing grape rootstocks that confer Pierces disease resistance to both the rootstock and the grafted scion, it will be necessary for cecropin A to circulate in the xylem vessels. To obtain expression of cecropin A in plant xylem, we are using a signal peptide sequence taken from a protein that naturally occurs in plant xylem. Glycine-rich proteins that are localized in plant xylem (Keller, et al., 1989; Morvan, et al., 2003) have been isolated and characterized (Sakuta and Satoh, 2000; Le Provost, et al., 2003). We are testing the rice glycine-rich protein signal peptide sequence, which confers vascular-specific expression in transgenic plants (Liu, et al., 2003), to determine if it will be effective to target cecropin A to plant xylem.
• Publication Date: Dec 2004
• Journal: 2004 Pierce's Disease Research Symposium