THE PIT MEMBRANE BARRIER TO XYLELLA FASTIDIOSA MOVEMENT IN GRAPEVINES: BIOCHEMICAL AND PHYSIOLOGICAL ANALYSIS

• Author(s): Labavitch, John; Greve, Carl; Matthews, Mark; Rost, Thomas; Sun, Qiang;
• Abstract: Studies planned for this proposal will (1) examine further the impacts of cell wall-degrading proteins on pit membrane integrity, (2) describe what our uses of the Xylella fastidiosa (Xf) cell wall-degrading enzymes tell us about the pit membrane polysaccharide network, and (3) specifically examine the relationship between pit membrane disruption, grapevine ethylene production, and xylem water conduit obstruction. Of particular interest because of its potential for identifying a new mechanism for a vines resistance to PD, will be tests of the role of Xf cell wall xyloglucan-degrading endo--1,4-glucanases (EGases) in increasing the pit membranes porosity and efforts to identify natural pant proteins that are inhibitors of those EGases. This is a new project, approved in Spring 2006, with funding beginning July 1. Dr. Alonso Prez-Donoso, who had recently finished his Ph.D. work in our laboratory was to have been the primary bench scientist in the project. However, he was offered a faculty position in Santiago, Chile and left to assume that position in early Spring 2006. Therefore, progress toward meeting our objectives has been slow. We are fortunate in that Dr. Quang Sun will be taking a position as a postdoctoral researcher in the project, beginning October 1, 2006. We anticipate rapid progress on Objectives 2 and 3 once Dr. Sun has become comfortable with his new laboratory environment. We have been able to begin testing of xyloglucanase-inhibiting proteins (XGIPs) on Xf EGase activity. Unfortunately, no inhibition was detected.
• Publication Date: Nov 2006
• Journal: 2006 Pierce's Disease Research Symposium