Chargaff's rule of intra-strand parity (ISP) between complementary mono/oligonucleotides in chromosomes is well established in the scientific literature. Although a large numbers of papers have been published citing works and discussions on ISP in the genomic era, scientists are yet to find all the factors responsible for such a universal phenomenon in the chromosomes. In the present work, we h...

Ordering genetic markers or clones from a genomic library into a physical map is a central problem in genetics. In the presence of errors, there is no efficient algorithm known that solves this problem. Based on a standard heuristic algorithm for it, we present a method to construct a confidence neighborhood for a computed solution. We compute a confidence value for putative local solutions der...

Xylella fastidiosa (Xf) is a xylem-limited bacterial pathogen that causes leaf scorch symptoms in numerous plant species in urban, agricultural, and natural ecosystems worldwide. The exact mechanism of hydraulic disruption and systemic colonization of xylem by Xf remains elusive across all host plants. To understand both processes better, the functional and structural characteristics of xylem i...

Title of Document: Chemotherapeutic Treatment Options to Manage Xylella fastidiosa in Shade Trees Darren DeStefano Master of Natural Resource Sciences 2005 Directed By: Associate Professor Joseph Sullivan Natural Resource Sciences and Landscape Architecture Xylella fastidiosa is a fastidious, xylem-limited, broad spectrum, bacterial plant pathogen native to the Americas, causing substantial eco...

INTRODUCTION Endophytic bacteria such as Xylella fastidiosa (Xf) colonize the internal tissues of the host, forming a structure very similar to a fixed biofilm inside the plant. A key determinant of success for an endophyte is the ability to move within the plant, sending out “scouts” to colonize new areas within the host. We expect activities required for movement to be most successful when ca...

Xylella fastidiosa (Xf) is the causative agent of Pierce’s Disease (PD). Collectively, a team of researchers (Lindow, Dandekar, Labavitch/Powell and Gilchrist) has identified or constructed and advanced the evaluation of five (Table 1) novel genes (DNA constructs) that, when engineered into grapevines, suppress symptoms of PD by reducing the titer of Xf in the plant, reducing its systemic sprea...

INTRODUCTION Current approaches to understanding the progression of Pierce’s disease are limited by the lack of genetic techniques that can be used to study the biology of Xylella fastidiosa (Xf). In particular, extrachromosomal elements, such as plasmids, having long-term stability in Xf when grown in lab cultures or en planta, have not yet been satisfactorily developed. We will develop vector...

Xylella fastidiosa (Xf) is a xylem-limited bacterium that lives as a harmless endophyte in most plant species but is pathogenic in several agriculturally important crops such as coffee, citrus, and grapevine (Vitis vinifera L.). In susceptible cultivars of grapevine, Xf infection results in leaf scorch, premature leaf senescence, and eventually vine death; a suite of symptoms collectively refer...

The phytopathogen Xylella fastidiosa causes economic losses in important agricultural crops. Xylem vessel occlusion caused by biofilm formation is the major mechanism underlying the pathogenicity of distinct strains of X. fastidiosa. Here, we provide a detailed in vitro characterization of the extracellular proteins of X. fastidiosa. Based on the results, we performed a comparison with a strain...

One of our target genes is a pear pgip cloned in the Labavitch lab (Stotz et al. 1993). PGIPs are proteins containing a leucinerich repeat domain that are targeted to the plant cell wall and that specifically inhibit fungal polygalacturonases (PGs). By inhibiting PGs, PGIPs directly interfere with host cell wall degradation and may thus prevent degradation of pectic oligomeric elicitors that ar...