Xylella fastidiosa Requires Polygalacturonase for Colonization and Pathogenicity in Vitis vinifera Grapevines

• Published in: Molecular plant-microbe interactions Vol. 20; no. 4; pp. 411 - 419
• Main Authors: Roper, M.C, Greve, L.C, Warren, J.G, Labavitch, J.M, Kirkpatrick, B.C
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.04.2007; The American Phytopathological Society
• Subjects: bacterial colonization; Biological and medical sciences; cell membranes; Cell Wall; cell walls; Cloning, Molecular; disease course; enzyme activity; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; genes; genome; grapes; microbial genetics; Mutagenesis; mutants; Open Reading Frames; pathogenesis; pathogenicity; pectinase; Phytopathology. Animal pests. Plant and forest protection; Pierce's disease; Plant Diseases - microbiology; polygalacturonase; Polygalacturonase - genetics; Polygalacturonase - metabolism; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Virulence; Vitaceae; Vitis - microbiology; Vitis vinifera; Xylella - enzymology; Xylella - growth & development; Xylella - pathogenicity; Xylella fastidiosa; Xylem; Plant pathogen; Microbiology; Pathogenesis; Virulence; Vitis vinifera; Mechanism; Cell wall; Gene; Vitidaceae; Dicotyledones; Angiospermae; Bacteria; d: pectinase; Enzyme; Transposable element; Polygalacturonase; IS element; Pathogenicity; Factor X; Fruit crop; Glycosidases; Hydrolases; Membrane pore; Spermatophyta; Xylan endo-1,3-β-xylosidase; Mutation; Genome; O-Glycosidases
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI-20-4-0411

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, based on the presence of genes involved in plant cell wall degradation in the X. fastidiosa genome. These genes include several beta-1,4 endoglucanases, several xylanases, several xylosidases, and one polygalacturonase (PG). In this study, we demonstrated that the pglA gene encodes a functional PG. A mutant in pglA lost pathogenicity and was compromised in its ability to systemically colonize Vitis vinifera grapevines. The results indicate that PG is required for X. fastidiosa to successfully infect grapevines and is a critical virulence factor for X. fastidiosa pathogenesis in grapevine.