MECHANISMS OF PIERCES DISEASE TRANSMISSION IN GRAPEVINES: AN ANALYSIS OF THE MOVEMENT OF XYLELLA FASTIDIOSA IN XYLEM PATHWAYS

• Author(s): Matthews, Mark; Rost, Thomas; Stevenson, Joshua;
• Abstract: Pierces disease (PD) is a consequence of the spread of xylem-limited bacteria, bacterial products, or plant responses to either leading to blockage of water movement within the grapes hydraulic network (Hopkins and Mollenhauer 1973). The progression of symptoms and movement of PD pathogens from the point of inoculation into the hydraulic network is poorly understood. The development of xylem blockage from the inoculation point to distal or basal organs and the pathways for movement of bacteria within grapevines needs to be determined. The general vegetative anatomy and the primary vascularization of grapevine have been summarized (Pratt 1974, Mullins et al. 1992, Fournioux 1982) and anatomical symptoms of PD have been documented (Esau 1948, Tyson et al. 1985). Although a general pattern of grapevine hydraulic architecture has been proposed, the vascular arrangement within grapevine must be studied in the context of the spread of PD within the plant from the site of inoculation to a systemic presence. It is unknown whether the mechanisms of pathenogenesis of PD are a direct result of xylem blockage by the bacteria (Hopkins 1981), phytotoxins produced by the bacteria (Lee et al. 1982), resultant gums and tyloses produced by the plant (Esau 1948), or a combination of these factors.
• Publication Date: Dec 2002
• Journal: 2002 Pierce's Disease Research Symposium