Role of Rhizobium endoglucanase CelC2 in cellulose biosynthesis and biofilm formation on plant roots and abiotic surfaces

Microbial Cell Factories

Research

E Martínez-Molina¹  L Rivera¹  R Rivas¹  Pedro F Mateos¹  E Velázquez¹  M Robledo²  F Dazzo³  Ann M Hirsch⁴  Jose I Jiménez-Zurdo⁵ 

[1] Departamento de Microbiología y Genética and CIALE, Universidad de Salamanca, Salamanca, Spain;Departamento de Microbiología y Genética and CIALE, Universidad de Salamanca, Salamanca, Spain;LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany;Department of Microbiology and Molecular Genetics, Michigan State University, Lansing, USA;Department of Molecular, Cell and Developmental Biology and Molecular Biology Institute, University of California-Los Angeles, Los Angeles, USA;Estación Experimental del Zaidín, CSIC, Granada, Spain;

关键词: Cellulose biosynthesis;    Rhizobium;    Cellulases;    Biofilm;    Symbiosis;   

DOI  :  10.1186/1475-2859-11-125

 received in 2012-05-21, accepted in 2012-09-06,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe synthesis of cellulose is among the most important but poorly understood biochemical processes, especially in bacteria, due to its complexity and high degree of regulation. In this study, we analyzed both the production of cellulose by all known members of the Rhizobiaceae and the diversity of Rhizobium celABC operon predicted to be involved in cellulose biosynthesis. We also investigated the involvement in cellulose production and biofilm formation of celC gene encoding an endoglucanase (CelC2) that is required for canonical symbiotic root hair infection by Rhizobium leguminosarum bv. trifolii.ResultsANU843 celC mutants lacking (ANU843ΔC2) or overproducing cellulase (ANU843C2+) produced greatly increased or reduced amounts of external cellulose micro fibrils, respectively. Calcofluor-stained cellulose micro fibrils were considerably longer when formed by ANU843ΔC2 bacteria rather than by the wild-type strain, in correlation with a significant increase in their flocculation in batch culture. In contrast, neither calcofluor-stained extracellular micro fibrils nor flocculation was detectable in ANU843C2+ cells. To clarify the role of cellulose synthesis in Rhizobium cell aggregation and attachment, we analyzed the ability of these mutants to produce biofilms on different surfaces. Alteration of wild-type CelC2 levels resulted in a reduced ability of bacteria to form biofilms both in abiotic surfaces and in planta.ConclusionsOur results support a key role of the CelC2 cellulase in cellulose biosynthesis by modulating the length of the cellulose fibrils that mediate firm adhesion among Rhizobium bacteria leading to biofilm formation. Rhizobium cellulose is an essential component of the biofilm polysaccharidic matrix architecture and either an excess or a defect of this “building material” seem to collapse the biofilm structure. These results position cellulose hydrolytic enzymes as excellent anti-biofilm candidates.

【 授权许可】

Unknown   
© Robledo et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.