Title: Unintended Laboratory-Driven Evolution Reveals Genetic Requirements for Biofilm Formation by Desulfovibrio vulgaris Hildenborough

Abstract

ABSTRACT Biofilms of sulfate-reducing bacteria (SRB) are of particular interest as members of this group are culprits in corrosion of industrial metal and concrete pipelines as well as being key players in subsurface metal cycling. Yet the mechanism of biofilm formation by these bacteria has not been determined. Here we show that two supposedly identical wild-type cultures of the SRB Desulfovibrio vulgaris Hildenborough maintained in different laboratories have diverged in biofilm formation. From genome resequencing and subsequent mutant analyses, we discovered that a single nucleotide change within DVU1017, the ABC transporter of a type I secretion system (T1SS), was sufficient to eliminate biofilm formation in D. vulgaris Hildenborough. Two T1SS cargo proteins were identified as likely biofilm structural proteins, and the presence of at least one (with either being sufficient) was shown to be required for biofilm formation. Antibodies specific to these biofilm structural proteins confirmed that DVU1017, and thus the T1SS, is essential for localization of these adhesion proteins on the cell surface. We propose that DVU1017 is a member of the lapB category of microbial surface proteins because of its phenotypic similarity to the adhesin export system described for biofilm formation in the environmental pseudomonads. These findings have ledmore » to the identification of two functions required for biofilm formation in D. vulgaris Hildenborough and focus attention on the importance of monitoring laboratory-driven evolution, as phenotypes as fundamental as biofilm formation can be altered. IMPORTANCE The growth of bacteria attached to a surface (i.e., biofilm), specifically biofilms of sulfate-reducing bacteria, has a profound impact on the economy of developed nations due to steel and concrete corrosion in industrial pipelines and processing facilities. Furthermore, the presence of sulfate-reducing bacteria in oil wells causes oil souring from sulfide production, resulting in product loss, a health hazard to workers, and ultimately abandonment of wells. Identification of the required genes is a critical step for determining the mechanism of biofilm formation by sulfate reducers. Here, the transporter by which putative biofilm structural proteins are exported from sulfate-reducing Desulfovibrio vulgaris Hildenborough cells was discovered, and a single nucleotide change within the gene coding for this transporter was found to be sufficient to completely stop formation of biofilm.« less

Authors:

De León, Kara B.  ^[1];

• Search DOE PAGES for author "De León, Kara B."
• Search DOE PAGES for ORCID "0000-0002-2499-5650"

Zane, Grant M.  ^[1];

• Search DOE PAGES for author "Zane, Grant M."
• Search DOE PAGES for ORCID "0000-0002-3357-3097"

Trotter, Valentine V. ^[2]; Krantz, Gregory P. ^[3]; Arkin, Adam P. ^[4]; Butland, Gareth P. ^[2]; Walian, Peter J.  ^[5];

• Search DOE PAGES for author "Walian, Peter J."
• Search DOE PAGES for ORCID "0000-0001-7405-902X"

Fields, Matthew W.  ^[3];

• Search DOE PAGES for author "Fields, Matthew W."
• Search DOE PAGES for ORCID "0000-0001-9053-1849"

Wall, Judy D. ^[1]; Parsek, ed., Matthew R.; Spormann, Alfred; Finkel, Steven

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+ Show Author Affiliations

1. Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
2. Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
3. Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA, Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
4. Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA, Department of Bioengineering, University of California, Berkeley, California, USA
5. Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA

Publication Date:

Wed Nov 08 00:00:00 EST 2017

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1786913

Alternate Identifier(s):

OSTI ID: 1417607

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Published Article

Journal Name:

mBio

Additional Journal Information:

Journal Name: mBio Journal Volume: 8 Journal Issue: 5; Journal ID: ISSN 2161-2129

Publisher:

American Society for Microbiology

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; Desulfovibrio vulgaris; biofilms; genetic polymorphisms; secretion systems; sulfate reduction