Clustering of mutations blocking synthesis of xanthan gum by Xanthomonas campestris

Thorne, Linda; Tansey, Lisa; Pollock, Thomas J.

doi:10.1128/jb.169.8.3593-3600.1987

Cited by 68 publications

(30 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…campestris has been studied in some detail as a model organism for investigation of the genetics of bacterial phytopathogenicity. Use of molecular genetic tools (9,44) has led to the cloning of genes essential for xanthan synthesis (20,43) and production of protease (42), cellulase (17), and polygalacturonate lyase (11), as well as genes that code for positive and negative regulators of extracellular enzyme production and secretion (9). Mutations in any of these genes affect virulence, apparently without affecting bacterial growth ex planta.…”

mentioning

confidence: 99%

A Xanthomonas campestris pv. campestris protein similar to catabolite activation factor is involved in regulation of phytopathogenicity

et al. 1990

View full text Add to dashboard Cite

A DNA fragment from Xanthomonas campestris pv. campestris that partially restored the carbohydrate fermentation pattern of a cya crp Escherichia coli strain was cloned and expressed in E. coli. The nucleotide sequence of this fragment revealed the presence of a 700-base-pair open reading frame that coded for a protein highly similar to the catabolite activation factor (CAP) of E. coli (accordingly named CLP for CAP-like protein). An X. campestris pv. campestris clp mutant was constructed by reverse genetics. This strain was not affected in the utilization of various carbon sources but had strongly reduced pathogenicity. Production of xanthan gum, pigment, and extracellular enzymes was either increased or decreased, suggesting that CLP plays a role in the regulation of phytopathogenicity.

show abstract

mentioning

confidence: 99%

A Xanthomonas campestris pv. campestris protein similar to catabolite activation factor is involved in regulation of phytopathogenicity

et al. 1990

View full text Add to dashboard Cite

show abstract

“…In X. campestris, as reported for Agrobacterium tumefaciens (5,26), Erwinia stewartii (7), R. meliloti (27), Rhizobiium leguminosarum biovar phaseoli (11), Rhizobium sp. strain NGR234 (6), Pseudomonas aeruginosa (10), Zoogloea ramigera (14), a cluster of genes essential for xanthan polysaccharide synthesis has been isolated (2,16,34). Experiments designed to determine the function of the remaining xps gene products are in progress.…”

Section: Discussionmentioning

confidence: 99%

“…Several genetic loci are involved in the biosynthesis of xanthan gum (2,16,34). Harding et al have shown that mutations affecting xanthan polysaccharide synthesis (xps) are clustered in a 13.5-kb region and fall into at least five complementation groups (16).…”

mentioning

confidence: 99%

Location and cloning of the ketal pyruvate transferase gene of Xanthomonas campestris

et al. 1991

View full text Add to dashboard Cite

Genes required for xanthan polysaccharide synthesis (xps) are clustered in a DNA region of 13.5 kb in the chromosome of Xanthomonas campestris. Plasmid pCHC3 containing a 12.4-kb insert of xps genes has been suggested to include a gene involved in the pyruvylation of xanthan gum (N.E. Harding, J.M. Cleary, D.K. Cabañas, I. G. Rosen, and K. S. Kang, J. Bacteriol. 169:2854-2861, 1987). An essential step toward understanding the biosynthesis of xanthan gum and to enable genetic manipulation of xanthan structure is the determination of the biochemical function encoded by the xps genes. On the basis of biochemical characterization of an X. campestris mutant which produces pyruvate-free xanthan gum, complementation studies, and heterologous expression, we have identified the gene coding for the ketal pyruvate transferase (kpt) enzyme. This gene was located on a 1.4-kb BamHI fragment of pCHC3 and cloned in the broad-host-range cloning vector pRK404. An X. campestris kpt mutant was constructed by mini-Mu(Tetr) mutagenesis of the cloned gene and then by recombination of the mutation into the chromosome of the wild-type strain.

show abstract

“…In the first, the repeating unit is sequentially assembled linked to a polyprenol through a diphosphate bridge. In the second The genes that encode the enzymes involved in the transfer of the sugars and of the non-glycosidic substituents are located in a cluster (Barrere et al, 1986;Harding et al, 1987;Thorne et al, 1987) which comprises 12 predicted ORFs, gumB-gumM (Capage et al, 1987;Vanderslice et al, 1990). Transcriptional analysis has shown that the gum genes are mainly expressed as an operon from a promoter upstream of the first gene, gumB (Katzen et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Evidence for a role for the gumB and gumC gene products in the formation of xanthan from its pentasaccharide repeating unit by Xanthomonas campestris

et al. 1998

View full text Add to dashboard Cite

The biosynthesis of the extracellular polysaccharide xanthan in Xanthomonas campestris pv. campestris is directed by a cluster of 12 genes, gumB-umM. Several xanthan-deficient mutants of the wild-type strain 8004 have previously been described which carry Tn5 insertions in this region of the chromosome. Here it is shown that the transposon insertion in one of these mutants, strain 8397, is located 15 bp upstream of the translational start site of the gumB gene. EDTA-treated cells of strain 8397 were able to synthesize the lipid-linked pentasaccharide repeating unit of xanthan from the three nucleotide sugar donors (UDP-glucose, GDP-mannose and UDP-glucuronic acid) but were unable to polymerize the pentasaccharide into mature xanthan. A subclone of the gum gene cluster carrying gumB and gumC restored xanthan production to strain 8397 to levels approximately 28% of the wild-type. In contrast, subclones carrying gumB or gumC alone were not effective. These results are discussed with reference to previous speculations, based on computer analysis, that gumB and gumC are both involved in the translocation of xanthan across the bacterial membranes.

show abstract

Clustering of mutations blocking synthesis of xanthan gum by Xanthomonas campestris

Cited by 68 publications

References 22 publications

A Xanthomonas campestris pv. campestris protein similar to catabolite activation factor is involved in regulation of phytopathogenicity

A Xanthomonas campestris pv. campestris protein similar to catabolite activation factor is involved in regulation of phytopathogenicity

Location and cloning of the ketal pyruvate transferase gene of Xanthomonas campestris

Evidence for a role for the gumB and gumC gene products in the formation of xanthan from its pentasaccharide repeating unit by Xanthomonas campestris

Contact Info

Product

Resources

About