Genomic distribution of B-vitamin auxotrophy and uptake transporters in environmental bacteria from the Chloroflexi phylum


Bacteria from the Chloroflexi phylum are dominant members of phototrophic microbial mat communities in terrestrial thermal environments. Vitamins of B group are key intermediates (precursors) in the biosynthesis of indispensable enzyme cofactors driving numerous metabolic processes in all forms of life. A genomics-based reconstruction and comparative analysis of respective biosynthetic and salvage pathways and riboswitch regulons in over 20 representative Chloroflexi genomes revealed a widespread auxotrophy for some of the vitamins. The most prominent predicted phenotypic signature, auxotrophy for vitamins B1 and B7 was experimentally confirmed for the best studied model organism Chloroflexus aurantiacus. These observations along with identified candidate genes for the respective uptake transporters pointed to B vitamin cross-feeding as an important aspect of syntrophic metabolism in microbial communities. Inferred specificities of homologous substrate-binding components of ABC transporters for vitamins B1 (ThiY) and B2 (RibY) were verified by thermofluorescent shift approach. A functional activity of the thiamine-specific transporter ThiXYZ from C. aurantiacus was experimentally verified by genetic complementation in E. coli. Expanding the integrative approach, which was applied here for a comprehensive analysis of B-vitamin metabolism in Chloroflexi would allow reconstruction of metabolic interdependencies in microbial communities.


PubMed ID: 25345570

Projects: Adaptive Responses, Energy and Material Processing, Microbial Community Dynamics

Publication type: Not specified

Journal: Environ Microbiol Rep


Date Published: 28th Oct 2014

Registered Mode: Not specified

Authors: I. A. Rodionova, X. Li, A. E. Plymale, K. Motamedchaboki, A. E. Konopka, , , A. L. Osterman, D. A. Rodionov

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Created: 13th Jan 2015 at 19:14

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