Xylella fastidiosa (Xf) is a xylem-dwelling bacterium responsible for the death of grapevine (Pierce’s disease) and other economically important species such as almond, citrus, and coffee.  However, other plants harbor the bacteria with little or no visible symptoms.  In order to better comprehend how the xylem network might control bacterial movement in susceptible plants and thus provide a better understanding of the Pierce’s disease, we are investigating the xylem structure and its relation to the movement of Xf by comparing different hosts that are able to support systemic and non-systemic Xf infection.

Symptoms (leaf scorch) appears several months after inoculation of the grapevines with fluorescent GFP-Xf. Anatomical observation revealed that GFP-Xf was present in the petiole and in the veins of the lamina, but they never reached the margin of the leaf were the vessels with open perforation plate (OPP movie) are replaced by tracheids (Vein ending movie).