In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 64, No. 9 ( 1998-09), p. 3180-3187
Kurzfassung:
Plant-pathogenic bacteria produce various extracellular polysaccharides (EPSs) which may function as virulence factors in diseases caused by these bacteria. The EPS levan is synthesized by the extracellular enzyme levansucrase in Pseudomonas syringae , Erwinia amylovora , and other bacterial species. The lsc genes encoding levansucrase from P. syringae pv. glycinea PG4180 and P. syringae pv. phaseolicola NCPPB 1321 were cloned, and their nucleotide sequences were determined. Heterologous expression of the lsc gene in Escherichia coli was found in four and two genomic library clones of strains PG4180 and NCPPB 1321, respectively. A 3.0-kb Pst I fragment common to all six clones conferred levan synthesis on E. coli when further subcloned. Nucleotide sequence analysis revealed a 1,248-bp open reading frame (ORF) derived from PG4180 and a 1,296-bp ORF derived from NCPPB 1321, which were both designated lsc . Both ORFs showed high homology to the E. amylovora and Zymomonas mobilis lsc genes at the nucleic acid and deduced amino acid sequence levels. Levansucrase was not secreted into the supernatant but was located in the periplasmic fraction of E. coli harboring the lsc gene. Expression of lsc was found to be dependent on the vector-based P lac promoter, indicating that the native promoter of lsc was not functional in E. coli . Insertion of an antibiotic resistance cassette in the lsc gene abolished levan synthesis in E. coli . A PCR screening with primers derived from lsc of P. syringae pv. glycinea PG4180 allowed the detection of this gene in a number of related bacteria.
Materialart:
Online-Ressource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.64.9.3180-3187.1998
Sprache:
Englisch
Verlag:
American Society for Microbiology
Publikationsdatum:
1998
ZDB Id:
223011-2
ZDB Id:
1478346-0
SSG:
12
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