Xylella fastidiosa is the causal agent of Pierce's disease of grape, an economically significant disease for the grape industry. X. fastidiosa systemically colonizes the xylem elements of grapevines and is able to breach the pit pore membranes separating xylem vessels by unknown mechanisms. We hypothesized that X. fastidiosa utilizes cell wall degrading enzymes to break down pit membranes, base...

Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some...

Bacterial leaf scorch is caused by Xylella fastidiosa Wells et al. The pathogen causes chronic leaf scorch and decline in elm, oak, sycamore, and maple. X. fastidiosa has a wide host range and is responsible for many other serious diseases including Pierce's disease of grape, phony disease of peach, and citrus variegated chlorosis. Its role in shade tree disorders has only recently been recogni...

INTRODUCTION One of our projects involved the development of a transformation and transposon mutagenesis systems for the bacterium that causes Pierce's disease (PD), Xylella fastidiosa (Xf). We now have a random transposon mutagenesis system working for Xf (Guilhabert, et al. 2001) and recently we have developed an E. coli/Xf plasmid shuttle vector. We are currently assessing the stability of t...

Phytoplasmas and Xylella spp. are bacteria that cause many economically important plant diseases worldwide. TaqMan probe-based quantitative real-time polymerase chain reaction (qPCR) assays have been utilized to universally detect phytoplasmas or Xylella fastidiosa. To develop a superior universal qPCR method, we used a dual priming oligonucleotide (DPO) with two annealing sites as a reverse pr...

The draft genome sequence of Xylella fastidiosa CO33 isolate, retrieved from symptomatic leaves of coffee plant intercepted in northern Italy, is reported. The CO33 genome size is 2,681,926 bp with a GC content of 51.7%.

Using a modified multilocus sequence typing (MLST) scheme for the bacterial plant pathogen Xylella fastidiosa based on the same seven housekeeping genes employed in a previously published MLST, we studied the genetic diversity of two subspecies, X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. sandyi, which cause Pierce's disease and oleander leaf scorch, respectively. Typing of 85 U.S....

The identification of genetic factors that enable Xylella fastidiosa to express Pierce’s disease symptoms is essential to the further development of several disease control strategies. One such control strategy is to use non-pathogenic derivatives of the Pierce’s disease pathogen itself to competitively exclude pathogenic strains in grapevines. We have made progress in the development of geneti...

The Ohr (organic hydroperoxide resistance) family of 15-kDa Cys-based, thiol-dependent peroxidases is central to the bacterial response to stress induced by organic hydroperoxides but not by hydrogen peroxide. Ohr has a unique three-dimensional structure and requires dithiols, but not monothiols, to support its activity. However, the physiological reducing system of Ohr has not yet been identif...