General Information: This strain was derived from a pathogenic strain (8.1b) isolated in 1992 in France that had come from infected twigs derived from the sweet orange strain Valencia in Brazil in the same year. This organism was first identified in 1993 as the causal agent of citrus variegated chlorosis, a disease that affects varieties of sweet oranges. Other strains of this species cause a range of diseases in mulberry, pear, almond, elm, sycamore, oak, maple, pecan and coffee which collectively result in multimillion dollar devastation of economically important plants. Xylella fastidiosa is similar to Xanthomonas campestris pv. campestris in that it produces a wide variety of pathogenic factors for colonization in a host-specific manner including a large number of fimbrial and afimbrial adhesins for attachment. It does not contain a type III secretion system, but possesses genes for a type II secretion system for export of exoenzymes that degrade the plant cell wall and allow the bacterium to colonize the plant xylem.