Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticus

Abstract Background Utilizing unique carbohydrates or utilizing them more efficiently help bacteria expand and colonize new niches. Horizontal gene transfer (HGT) of catabolic systems is a powerful mechanism by which bacteria can acquire new phenotypic traits that can increase survival and fitness i...

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Main Authors: Abish Regmi, Ethna Fidelma Boyd
Format: Article
Language:English
Published: BMC 2019-05-01
Series:BMC Microbiology
Subjects:
Online Access:http://link.springer.com/article/10.1186/s12866-019-1487-6
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author Abish Regmi
Ethna Fidelma Boyd
author_facet Abish Regmi
Ethna Fidelma Boyd
author_sort Abish Regmi
collection DOAJ
description Abstract Background Utilizing unique carbohydrates or utilizing them more efficiently help bacteria expand and colonize new niches. Horizontal gene transfer (HGT) of catabolic systems is a powerful mechanism by which bacteria can acquire new phenotypic traits that can increase survival and fitness in different niches. In this work, we examined carbon catabolism diversity among Vibrio parahaemolyticus, a marine species that is also an important human and fish pathogen. Results Phenotypic differences in carbon utilization between Vibrio parahaemolyticus strains lead us to examine genotypic differences in this species and the family Vibrionaceae in general. Bioinformatics analysis showed that the ability to utilize d-galactose was present in all V. parahaemolyticus but at least two distinct transporters were present; a major facilitator superfamily (MFS) transporter and a sodium/galactose transporter (SGLT). Growth and genetic analyses demonstrated that SGLT was a more efficient transporter of d-galactose and was the predominant type among strains. Phylogenetic analysis showed that d-galactose gene galM was acquired multiples times within the family Vibrionaceae and was transferred between distantly related species. The ability to utilize d-gluconate was universal within the species. Deletion of eda (VP0065), which encodes aldolase, a key enzyme in the Entner-Doudoroff (ED) pathway, reached a similar biomass to wild type when grown on d-gluconate as a sole carbon source. Two additional eda genes were identified, VPA1708 (eda2) associated with a d-glucuronate cluster and VPA0083 (eda3) that clustered with an oligogalacturonide (OGA) metabolism cluster. EDA2 and EDA3 were variably distributed among the species. A metabolic island was identified that contained citrate fermentation, l-rhamnose and OGA metabolism clusters as well as a CRISPR-Cas system. Phylogenetic analysis showed that CitF and RhaA had a limited distribution among V. parahaemolyticus, and RhaA was acquired at least three times. Within V. parahaemolyticus, two different regions contained the gene for L-arabinose catabolism and most strains had the ability to catabolism this sugar. Conclusion Our data suggest that horizontal transfer of metabolic systems among Vibrionaceae is an important source of metabolic diversity. This work identified four EDA homologues suggesting that the ED pathway plays a significant role in metabolism. We describe previously uncharacterized metabolism islands that were hotspots for the gain and loss of functional modules likely mediated by transposons.
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spelling doaj.art-a356132bbdc7413eb56a5c6355d048082022-12-21T17:13:21ZengBMCBMC Microbiology1471-21802019-05-0119112010.1186/s12866-019-1487-6Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticusAbish Regmi0Ethna Fidelma Boyd1Department of Biological Sciences, University of DelawareDepartment of Biological Sciences, University of DelawareAbstract Background Utilizing unique carbohydrates or utilizing them more efficiently help bacteria expand and colonize new niches. Horizontal gene transfer (HGT) of catabolic systems is a powerful mechanism by which bacteria can acquire new phenotypic traits that can increase survival and fitness in different niches. In this work, we examined carbon catabolism diversity among Vibrio parahaemolyticus, a marine species that is also an important human and fish pathogen. Results Phenotypic differences in carbon utilization between Vibrio parahaemolyticus strains lead us to examine genotypic differences in this species and the family Vibrionaceae in general. Bioinformatics analysis showed that the ability to utilize d-galactose was present in all V. parahaemolyticus but at least two distinct transporters were present; a major facilitator superfamily (MFS) transporter and a sodium/galactose transporter (SGLT). Growth and genetic analyses demonstrated that SGLT was a more efficient transporter of d-galactose and was the predominant type among strains. Phylogenetic analysis showed that d-galactose gene galM was acquired multiples times within the family Vibrionaceae and was transferred between distantly related species. The ability to utilize d-gluconate was universal within the species. Deletion of eda (VP0065), which encodes aldolase, a key enzyme in the Entner-Doudoroff (ED) pathway, reached a similar biomass to wild type when grown on d-gluconate as a sole carbon source. Two additional eda genes were identified, VPA1708 (eda2) associated with a d-glucuronate cluster and VPA0083 (eda3) that clustered with an oligogalacturonide (OGA) metabolism cluster. EDA2 and EDA3 were variably distributed among the species. A metabolic island was identified that contained citrate fermentation, l-rhamnose and OGA metabolism clusters as well as a CRISPR-Cas system. Phylogenetic analysis showed that CitF and RhaA had a limited distribution among V. parahaemolyticus, and RhaA was acquired at least three times. Within V. parahaemolyticus, two different regions contained the gene for L-arabinose catabolism and most strains had the ability to catabolism this sugar. Conclusion Our data suggest that horizontal transfer of metabolic systems among Vibrionaceae is an important source of metabolic diversity. This work identified four EDA homologues suggesting that the ED pathway plays a significant role in metabolism. We describe previously uncharacterized metabolism islands that were hotspots for the gain and loss of functional modules likely mediated by transposons.http://link.springer.com/article/10.1186/s12866-019-1487-6Sodium/galactose transporter SGLTl-rhamnosel-arabinoseEntner-Doudoroff aldolase (EDA)Metabolism islandsCitrate fermentation
spellingShingle Abish Regmi
Ethna Fidelma Boyd
Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticus
BMC Microbiology
Sodium/galactose transporter SGLT
l-rhamnose
l-arabinose
Entner-Doudoroff aldolase (EDA)
Metabolism islands
Citrate fermentation
title Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticus
title_full Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticus
title_fullStr Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticus
title_full_unstemmed Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticus
title_short Carbohydrate metabolic systems present on genomic islands are lost and gained in Vibrio parahaemolyticus
title_sort carbohydrate metabolic systems present on genomic islands are lost and gained in vibrio parahaemolyticus
topic Sodium/galactose transporter SGLT
l-rhamnose
l-arabinose
Entner-Doudoroff aldolase (EDA)
Metabolism islands
Citrate fermentation
url http://link.springer.com/article/10.1186/s12866-019-1487-6
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AT ethnafidelmaboyd carbohydratemetabolicsystemspresentongenomicislandsarelostandgainedinvibrioparahaemolyticus