Functional analysis of genes for benzoate metabolism in the albicidin biosynthetic region of Xanthomonas albilineans

Hashimi, Saeed M. and Birch, Robert G. (2010) Functional analysis of genes for benzoate metabolism in the albicidin biosynthetic region of Xanthomonas albilineans. Applied Microbiology and Biotechnology, 87 4: 1475-1485. doi:10.1007/s00253-010-2620-5


Author Hashimi, Saeed M.
Birch, Robert G.
Title Functional analysis of genes for benzoate metabolism in the albicidin biosynthetic region of Xanthomonas albilineans
Formatted title
Functional analysis of genes for benzoate metabolism in the albicidin biosynthetic region of Xanthomonas albilineans
Journal name Applied Microbiology and Biotechnology   Check publisher's open access policy
ISSN 0175-7598
1432-0614
Publication date 2010-07-01
Sub-type Article (original research)
DOI 10.1007/s00253-010-2620-5
Volume 87
Issue 4
Start page 1475
End page 1485
Total pages 11
Editor Alexander Steinbüchel
Place of publication Berlin, Germany
Publisher Springer
Collection year 2011
Language eng
Formatted abstract
Albicidins are potent DNA-gyrase-inhibiting antibiotics and phytotoxins synthesised by Xanthomonas albilineans. Functions have been deduced for some clustered biosynthetic genes, including a PKS-NRPS megasynthase, methyltransferases and regulatory genes, and resistance genes including a transporter and a gyrase-binding protein. More puzzling is the presence in this cluster of apparent aromatic metabolism genes. Here, we describe functional analysis of several such genes and propose a model for their role. An apparent benzoate CoA ligase (xabE) proved essential for albicidin production and pathogenicity. A neighbouring operon includes genes for p-aminobenzoate (PABA) metabolism. A PABA synthase fusion (pabAB) restored prototrophy in pabA and pabB mutants of Escherichia coli, proving functionality. Inactivation of pabAB increased susceptibility to sulphanilamide but did not block albicidin production. X. albilineans contains a remote pabB gene which evidently supplies enough PABA for albicidin biosynthesis in culture. Additional capacity from pabAB may be advantageous in more demanding environments such as infected plants. Downstream from pabAB are a known resistance gene (albG) and ubiC which encodes a p-hydroxybenzoate (PHBA) synthase. PHBA protects X. albilineans from inhibition by PABA. Therefore, coordinated expression may protect X. albilineans against toxicity of both the PABA intermediate and the albicidin product, under conditions that induce high-level antibiotic biosynthesis.
© Springer-Verlag 2010
Keyword Benzoate CoA ligase
PABA synthase
PabAB fusion
PHBA synthase
Albicidin
Benzoate metabolism
Xanthomonas albilineans
p-Aminobenzoic acid
Leaf scald disease
Escherichia-coli
Aminodeoxychorismate synthase
DNA gyrase
Polyketide
Resistance
Chorismate
Sugarcane
Bacteria
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Agriculture and Food Sciences
 
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Created: Sun, 11 Jul 2010, 10:09:15 EST