INVESTIGADORES
FERREIRO Diego Ulises
artículos
Título:
Xanthomonas campestris pv. campestris gum mutants: effects on xanthan biosynthesis and plant virulence
Autor/es:
KATZEN F, FERREIRO DU, ODDO CG, IELMINI MV, BECKER A, PÜHLER A, IELPI L.
Revista:
JOURNAL OF BACTERIOLOGY
Referencias:
Año: 1998 vol. 180 p. 1607 - 1617
ISSN:
0021-9193
Resumen:
Xanthan is an industrially important exopolysaccharide produced by the
phytopathogenic, gram-negative bacterium Xanthomonas campestris pv.
campestris. It is composed of polymerized pentasaccharide repeating
units 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.