Sinorhizobium meliloti flavin secretion and bacteria-host interaction: role of the bifunctional RibBA protein

Svetlana N Yurgel; Jennifer Rice; Elizabeth Domreis; Joseph Lynch; Na Sa; Zeeshan Qamar; Sathish Rajamani; Mengsheng Gao; Sanja Roje; Wolfgang D Bauer

doi:10.1094/MPMI-11-13-0338-R

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Sinorhizobium meliloti flavin secretion and bacteria-host interaction: role of the bifunctional RibBA protein

Journal article

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Sinorhizobium meliloti flavin secretion and bacteria-host interaction: role of the bifunctional RibBA protein

Svetlana N Yurgel, Jennifer Rice, Elizabeth Domreis, Joseph Lynch, Na Sa, Zeeshan Qamar, Sathish Rajamani, Mengsheng Gao, Sanja Roje and Wolfgang D Bauer

Molecular plant-microbe interactions, Vol.27(5), pp.437-445

05/2014

DOI: https://doi.org/10.1094/MPMI-11-13-0338-R

Handle:

https://hdl.handle.net/2376/107399

PMID: 24405035

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https://doi.org/10.1094/MPMI-11-13-0338-RView

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Abstract

Symbiosis

Sequence Deletion

Sinorhizobium meliloti - genetics

Gene Expression

Intramolecular Transferases - genetics

Sinorhizobium meliloti - physiology

Bacterial Proteins - genetics

Biofilms - growth & development

Recombinant Proteins

Riboflavin - analysis

GTP Cyclohydrolase - metabolism

Medicago sativa - microbiology

Plant Roots - microbiology

Intramolecular Transferases - metabolism

Phenotype

Plant Root Nodulation

Riboflavin - secretion

Bacterial Proteins - metabolism

GTP Cyclohydrolase - genetics

Nitrogen Fixation

Sinorhizobium meliloti, the nitrogen-fixing bacterial symbiont of Medicago spp. and other legumes, secretes a considerable amount of riboflavin. This precursor of the cofactors flavin mononucleotide and flavin adenine dinucleotide is a bioactive molecule that has a beneficial effect on plant growth. The ribBA gene of S. meliloti codes for a putative bifunctional enzyme with dihydroxybutanone phosphate synthase and guanosine triphosphate (GTP) cyclohydrolase II activities, catalyzing the initial steps of the riboflavin biosynthesis pathway. We show here that an in-frame deletion of ribBA does not cause riboflavin auxotrophy or affect the ability of S. meliloti to establish an effective symbiosis with the host plant but does affect the ability of the bacteria to secrete flavins, colonize host-plant roots, and compete for nodulation. A strain missing the RibBA protein retains considerable GTP cyclohydrolase II activity. Based on these results, we hypothesize that S. meliloti has two partly interchangeable modules for biosynthesis of riboflavin, one fulfilling the internal need for flavins in bacterial metabolism and the other producing riboflavin for secretion. Our data also indicate that bacteria-derived flavins play a role in communication between rhizobia and the legume host and that the RibBA protein is important in this communication process even though it is not essential for riboflavin biosynthesis and symbiosis.

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Title: Sinorhizobium meliloti flavin secretion and bacteria-host interaction: role of the bifunctional RibBA protein
Creators: Svetlana N Yurgel
Jennifer Rice
Elizabeth Domreis
Joseph Lynch
Na Sa
Zeeshan Qamar
Sathish Rajamani
Mengsheng Gao
Sanja Roje
Wolfgang D Bauer
Publication Details: Molecular plant-microbe interactions, Vol.27(5), pp.437-445
Academic Unit: Biological Chemistry, Institute of
Publisher: United States
Identifiers: 99900547400401842
Language: English
Resource Type: Journal article