The exopolysaccharide gene cluster Bcam1330–Bcam1341 is involved in Burkholderia cenocepacia biofilm formation, and its expression is regulated by c‐di‐GMP and Bcam1349

MicrobiologyOpen

Mustafa Fazli²  Yvonne McCarthy¹  Michael Givskov²  Robert P. Ryan¹ 

[1] Department of Microbiology, Biosciences Institute, University College Cork, Cork, Ireland;Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark

关键词: Biofilm;    Burkholderia cenocepacia;    c‐di‐GMP;    exopolysaccharide;   

DOI  :  10.1002/mbo3.61

来源: Wiley

【 摘 要 】

Abstract

In Burkholderia cenocepacia, the second messenger cyclic diguanosine monophosphate (c-di-GMP) has previously been shown to positively regulate biofilm formation and the expression of cellulose and type-I fimbriae genes through binding to the transcriptional regulator Bcam1349. Here, we provide evidence that cellulose and type-I fimbriae are not involved in B. cenocepacia biofilm formation in flow chambers, and we identify a novel Bcam1349/c-di-GMP-regulated exopolysaccharide gene cluster which is essential for B. cenocepacia biofilm formation. Overproduction of Bcam1349 in trans promotes wrinkly colony morphology, pellicle, and biofilm formation in B. cenocepacia. A screen for transposon mutants unable to respond to the overproduction of Bcam1349 led to the identification of a 12-gene cluster, Bcam1330–Bcam1341, the products of which appear to be involved in the production of a putative biofilm matrix exopolysaccharide and to be essential for flow-chamber biofilm formation. We demonstrate that Bcam1349 binds to the promoter region of genes in the Bcam1330–Bcam1341 cluster and that this binding is enhanced by the presence of c-di-GMP. Furthermore, we demonstrate that overproduction of both c-di-GMP and Bcam1349 leads to increased transcription of these genes, indicating that c-di-GMP and Bcam1349 functions together in regulating exopolysaccharide production from the Bcam1330–Bcam1341 gene cluster. Our results suggest that the product encoded by the Bcam1330–Bcam1341 gene cluster is a major exopolysaccharide that provides structural stability to the biofilms formed by B. cenocepacia, and that its production is regulated by c-di-GMP through binding to and promotion of the activity of the transcriptional regulator Bcam1349.

【 授权许可】

CC BY   
© 2012 The Authors. MicrobiologyOpen published by Blackwell Publishing Ltd.

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