Xanthomonas campestris pv. campestris gum mutants: Effects on xanthan biosynthesis and plant virulence
Xanthan is an industrially important exopolysaccharide produced by the phytopathogenic, gram-negative bacterium Xanthomonas campestris pv. campestris. It is composed of polymerized pentasaccharide repeating malts which are assembled by the sequential addition of glucose-1-phosphate, glucose, mannose...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1998 |
| País: | Argentina |
| Institución: | Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales |
| Repositorio: | Biblioteca Digital (UBA-FCEN) |
| Idioma: | inglés |
| OAI Identifier: | paperaa:paper_00219193_v180_n7_p1607_Katzen |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00219193_v180_n7_p1607_Katzen |
| Access Level: | acceso abierto |
| Palabra clave: | gene product glucose 1 phosphate glucuronic acid lipid mannose pentasaccharide phosphate protein transferase xanthan article bacterial virulence biosynthesis carboxy terminal sequence gene gene function mutant nonhuman nucleotide sequence priority journal xanthomonas campestris Base Sequence Genes, Bacterial Molecular Sequence Data Mutation Plant Diseases Polysaccharides, Bacterial Uridine Diphosphate Glucose Virulence Xanthomonas campestris Bacteria (microorganisms) Negibacteria Xanthomonas Xanthomonas campestris pv. campestris |
| Sumario: | Xanthan is an industrially important exopolysaccharide produced by the phytopathogenic, gram-negative bacterium Xanthomonas campestris pv. campestris. It is composed of polymerized pentasaccharide repeating malts which are assembled by the sequential addition of glucose-1-phosphate, glucose, mannose, glucuronic acid, and mannose on a polyprenol phosphate carrier (L. Ielpi, R. O. Couso, and M. A. Dankert, J. Bacteriol. 175:2490- 2500, 1993). A cluster of 12 genes in a region designated xpsI or gum has been suggested to encode proteins involved in the synthesis and polymerization of the lipid intermediate. However, no experimental evidence supporting this suggestion has been published. In this work, from the biochemical analysis of a defined set of X. campestris gum mutants, we report experimental data for assigning functions to the products of the gum genes. We also show that the first step in the assembly of the lipid-linked intermediate is severely affected by the combination of certain gum and non- gum mutations. In addition, we provide evidence that the C-terminal domain of the gumD gene product is sufficient for its glucosyl-1-phosphate transferase activity. Finally, we found that alterations in the later stages of xanthan biosynthesis reduce the aggressiveness of X. campestris against the plant. |
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