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Xiao-hua Zhang - One of the best experts on this subject based on the ideXlab platform.
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Comparative genomic analysis reveals the evolution and environmental adaptation strategies of Vibrios
BMC Genomics, 2018Co-Authors: Heyu Lin, Min Yu, Xiaolei Wang, Xiao-hua ZhangAbstract:BackgroundVibrios are among the most diverse and ecologically important marine bacteria, which have evolved many characteristics and lifestyles to occupy various niches. The relationship between genome features and environmental adaptation strategies is an essential part for understanding the ecological functions of Vibrios in the marine system. The advent of complete genome sequencing technology has provided an important method of examining the genetic characteristics of Vibrios on the genomic level.ResultsTwo Vibrio genomes were sequenced and found to occupy many unique orthologues families which absent from the previously genes pool of the complete genomes of Vibrios. Comparative genomics analysis found Vibrios encompass a steady core-genome and tremendous pan-genome with substantial gene gain and horizontal gene transfer events in the evolutionary history. Evolutionary analysis based on the core-genome tree suggested that V. fischeri emerged ~ 385 million years ago, along with the occurrence of cephalopods and the flourish of fish. The relatively large genomes, the high number of 16S rRNA gene copies, and the presence of R-M systems and CRISPR system help Vibrios live in various marine environments. Chitin-degrading related genes are carried in nearly all the Vibrio genomes. The number of chitinase genes in Vibrios has been extremely expanded compared to which in the most recent ancestor of the genus. The chitinase A genes were estimated to have evolved along with the genus, and have undergone significant purifying selective force to conserve the ancestral state.ConclusionsVibrios have experienced extremely genome expansion events during their evolutionary history, allowing them to develop various functions to spread globally. Despite their close phylogenetic relationships, Vibrios were found to have a tremendous pan-genome with a steady core-genome, which indicates the highly plastic genome of the genus. Additionally, the existence of various chitin-degrading related genes and the expansion of chitinase A in the genus demonstrate the importance of the chitin utilization for Vibrios. Defensive systems in the Vibrio genomes may protect them from the invasion of external DNA. These genomic features investigated here provide a better knowledge of how the evolutionary process has forged Vibrio genomes to occupy various niches.
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Comparative genomic analysis reveals the evolution and environmental adaptation strategies of Vibrios.
BMC Genomics, 2018Co-Authors: Heyu Lin, Xiaolei Wang, Xiao-hua ZhangAbstract:Vibrios are among the most diverse and ecologically important marine bacteria, which have evolved many characteristics and lifestyles to occupy various niches. The relationship between genome features and environmental adaptation strategies is an essential part for understanding the ecological functions of Vibrios in the marine system. The advent of complete genome sequencing technology has provided an important method of examining the genetic characteristics of Vibrios on the genomic level. Two Vibrio genomes were sequenced and found to occupy many unique orthologues families which absent from the previously genes pool of the complete genomes of Vibrios. Comparative genomics analysis found Vibrios encompass a steady core-genome and tremendous pan-genome with substantial gene gain and horizontal gene transfer events in the evolutionary history. Evolutionary analysis based on the core-genome tree suggested that V. fischeri emerged ~ 385 million years ago, along with the occurrence of cephalopods and the flourish of fish. The relatively large genomes, the high number of 16S rRNA gene copies, and the presence of R-M systems and CRISPR system help Vibrios live in various marine environments. Chitin-degrading related genes are carried in nearly all the Vibrio genomes. The number of chitinase genes in Vibrios has been extremely expanded compared to which in the most recent ancestor of the genus. The chitinase A genes were estimated to have evolved along with the genus, and have undergone significant purifying selective force to conserve the ancestral state. Vibrios have experienced extremely genome expansion events during their evolutionary history, allowing them to develop various functions to spread globally. Despite their close phylogenetic relationships, Vibrios were found to have a tremendous pan-genome with a steady core-genome, which indicates the highly plastic genome of the genus. Additionally, the existence of various chitin-degrading related genes and the expansion of chitinase A in the genus demonstrate the importance of the chitin utilization for Vibrios. Defensive systems in the Vibrio genomes may protect them from the invasion of external DNA. These genomic features investigated here provide a better knowledge of how the evolutionary process has forged Vibrio genomes to occupy various niches.
Rita R Colwell - One of the best experts on this subject based on the ideXlab platform.
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Occurence of Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio cholerae in the urbanized Guaraja bay, Amazonia, Brasil.
2019Co-Authors: Mylène Toubiana, Rita R Colwell, Diana Fernandez, J.-e Filho, J. Garnier, R. Rezende De Castro, M.-p Bonnet, Patrick MonfortAbstract:Little information is available on the presence of V. cholerae (VC), V. parahaemolyticus (VP) and V. vulnificus (VV) in the Amazonian region where the last cholera epidemic occurred in the early 1990s. The main objective of this study was to investigate occurrence of these Vibrios in the Guajara Bay, an important estuary along the Amazonian coast where Belem, the largest city of the Amazonia is located. Water and zooplankton samples were collected in September, 2017, at five stations in the estuary along a salinity gradient, from 0 to 20‰. Temperature of the water was ca. 29°C. Enumeration of the three Vibrio species was accomplished using APW enrichment and MPN-real-time PCR analysis. APW broths were spread onto CHROMagar™ Vibrio and presumptive Vibrio colonies were isolated for molecular identification. The total number of VC and VP varied from ca. 10 MPN/L to 110 MPN/L, and of VV from 4 MPN/L to 46 MPN/L. Highest levels were recorded for VC and VV when the salinity was ca. 2-4.6 ‰, and ca. 4.6 ‰, respectively. No pattern was observed for VP that could be correlated with salinity. The number of potentially pathogenic VP tdh+ and VP trh2+ varied from ca. 1 MPN/L to 4 MPN/L, and from 1 MPN/L to 2 MPN/L, respectively. The three Vibrios were detected on the copepods (Acartia tonsa) and on Cirriped nauplii, depending on the sites and the salinity. Of 109 Vibrio strains isolated at the five stations included in this study, 67 were identified as V. cholerae, 27 V. parahaemolyticus, and 15 V. vulnificus. The Vibrio species were widespread through the large salinity gradient of the Guajara bay, showing its relevance as a potential reservoir of these bacteria.
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climate influence on Vibrio and associated human diseases during the past half century in the coastal north atlantic
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Luigi Vezzulli, Rita R Colwell, Chiara Grande, Philip C Reid, Pierre Helaouet, Martin Edwards, Manfred G Hofle, Ingrid Brettar, Carla PruzzoAbstract:Climate change is having a dramatic impact on marine animal and plant communities but little is known of its influence on marine prokaryotes, which represent the largest living biomass in the world oceans and play a fundamental role in maintaining life on our planet. In this study, for the first time to our knowledge, experimental evidence is provided on the link between multidecadal climatic variability in the temperate North Atlantic and the presence and spread of an important group of marine prokaryotes, the Vibrios, which are responsible for several infections in both humans and animals. Using archived formalin-preserved plankton samples collected by the Continuous Plankton Recorder survey over the past half-century (1958-2011), we assessed retrospectively the relative abundance of Vibrios, including human pathogens, in nine areas of the North Atlantic and North Sea and showed correlation with climate and plankton changes. Generalized additive models revealed that long-term increase in Vibrio abundance is promoted by increasing sea surface temperatures (up to ∼1.5 °C over the past 54 y) and is positively correlated with the Northern Hemisphere Temperature (NHT) and Atlantic Multidecadal Oscillation (AMO) climatic indices (P < 0.001). Such increases are associated with an unprecedented occurrence of environmentally acquired Vibrio infections in the human population of Northern Europe and the Atlantic coast of the United States in recent years.
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Predicting the distribution of Vibrio spp. in the Chesapeake Bay: a Vibrio cholerae case study.
EcoHealth, 2009Co-Authors: Guillaume Constantin De Magny, Anwar Huq, Wen Long, Chris W. Brown, Raleigh R. Hood, Raghu Murtugudde, Rita R ColwellAbstract:Vibrio cholerae, the causative agent of cholera, is a naturally occurring inhabitant of the Chesapeake Bay and serves as a predictor for other clinically important Vibrios, including Vibrio parahaemolyticus and Vibrio vulnificus. A system was constructed to predict the likelihood of the presence of V. cholerae in surface waters of the Chesapeake Bay, with the goal to provide forecasts of the occurrence of this and related pathogenic Vibrio spp. Prediction was achieved by driving an available multivariate empirical habitat model estimating the probability of V. cholerae within a range of temperatures and salinities in the Bay, with hydrodynamically generated predictions of ambient temperature and salinity. The experimental predictions provided both an improved understanding of the in situ variability of V. cholerae, including identification of potential hotspots of occurrence, and usefulness as an early warning system. With further development of the system, prediction of the probability of the occurrence of related pathogenic Vibrios in the Chesapeake Bay, notably V. parahaemolyticus and V. vulnificus, will be possible, as well as its transport to any geographical location where sufficient relevant data are available.
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pathogenic Vibrio species in the marine and estuarine environment
2005Co-Authors: Carla Pruzzo, Rita R Colwell, Anwar Huq, Gianfranco DonelliAbstract:The genus Vibrio includes more than 30 species, at least 12 of which are pathogenic to humans and/or have been associated with foodborne diseases (Chakraborty et al., 1997). Among these species, Vibrio cholerae, serogroups O1 and O139, are the most important, since they are associated with epidemic and pandemic diarrhea outbreaks in many parts of the world (Centers for Disease Control and Prevention, 1995; Kaper et al., 1995). However, other species of Vibrios capable of causing diarrheal disease in humans have received greater attention in the last decade. These include Vibrio parahaemolyticus, a leading cause of foodborne disease outbreaks in Japan and Korea (Lee et al., 2001), Vibrio vulnificus, Vibrio alginolyticus, Vibrio damsela, Vibrio fluvialis, Vibrio furnissii, Vibrio hollisae, Vibrio metschnikovii, and Vibrio mimicus (Altekruse et al., 2000; Hoi et al., 1997). In the USA, Vibrio species have been estimated to be the cause of about 8000 illnesses annually (Mead et al., 1999). Vibrios can be classified as either halophilic or nonhalophilic, depending on their requirement for NaCl for optimal growth (Thompson et al., 2004). They are free-living bacteria in the aquatic environment throughout the world. They tend to be more common in warmer waters, notably when temperatures rise above 17 ◦C and, depending on the species, they tolerate a wide range of salinities (Wright et al., 1996). Given their abundance in water, Vibrio species are also commonly isolated from fish and shellfish, with 100-fold higher concentration in filter-feeding shellfish, such as oysters, than in the surrounding water (Wright et al., 1996). During the warm summer months, virtually 100% of oysters can carry V. vulnificus and/or V. parahaemolyticus (Cook et al., 2002b; Motes et al., 1998; Wright et al., 1996). “Epidemic” strains of V. cholerae, which carry specific virulence genes, cause the disease “cholera,” while “nonepidemic” strains are mainly associated with septicemia, gastroenteritis, and wound infections (Levine & Griffin, 1993). However, morbidity due to nonepidemic strains is relatively low, and, in some instances, it is unclear whether isolation of the organism
Heyu Lin - One of the best experts on this subject based on the ideXlab platform.
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Comparative genomic analysis reveals the evolution and environmental adaptation strategies of Vibrios
BMC Genomics, 2018Co-Authors: Heyu Lin, Min Yu, Xiaolei Wang, Xiao-hua ZhangAbstract:BackgroundVibrios are among the most diverse and ecologically important marine bacteria, which have evolved many characteristics and lifestyles to occupy various niches. The relationship between genome features and environmental adaptation strategies is an essential part for understanding the ecological functions of Vibrios in the marine system. The advent of complete genome sequencing technology has provided an important method of examining the genetic characteristics of Vibrios on the genomic level.ResultsTwo Vibrio genomes were sequenced and found to occupy many unique orthologues families which absent from the previously genes pool of the complete genomes of Vibrios. Comparative genomics analysis found Vibrios encompass a steady core-genome and tremendous pan-genome with substantial gene gain and horizontal gene transfer events in the evolutionary history. Evolutionary analysis based on the core-genome tree suggested that V. fischeri emerged ~ 385 million years ago, along with the occurrence of cephalopods and the flourish of fish. The relatively large genomes, the high number of 16S rRNA gene copies, and the presence of R-M systems and CRISPR system help Vibrios live in various marine environments. Chitin-degrading related genes are carried in nearly all the Vibrio genomes. The number of chitinase genes in Vibrios has been extremely expanded compared to which in the most recent ancestor of the genus. The chitinase A genes were estimated to have evolved along with the genus, and have undergone significant purifying selective force to conserve the ancestral state.ConclusionsVibrios have experienced extremely genome expansion events during their evolutionary history, allowing them to develop various functions to spread globally. Despite their close phylogenetic relationships, Vibrios were found to have a tremendous pan-genome with a steady core-genome, which indicates the highly plastic genome of the genus. Additionally, the existence of various chitin-degrading related genes and the expansion of chitinase A in the genus demonstrate the importance of the chitin utilization for Vibrios. Defensive systems in the Vibrio genomes may protect them from the invasion of external DNA. These genomic features investigated here provide a better knowledge of how the evolutionary process has forged Vibrio genomes to occupy various niches.
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Comparative genomic analysis reveals the evolution and environmental adaptation strategies of Vibrios.
BMC Genomics, 2018Co-Authors: Heyu Lin, Xiaolei Wang, Xiao-hua ZhangAbstract:Vibrios are among the most diverse and ecologically important marine bacteria, which have evolved many characteristics and lifestyles to occupy various niches. The relationship between genome features and environmental adaptation strategies is an essential part for understanding the ecological functions of Vibrios in the marine system. The advent of complete genome sequencing technology has provided an important method of examining the genetic characteristics of Vibrios on the genomic level. Two Vibrio genomes were sequenced and found to occupy many unique orthologues families which absent from the previously genes pool of the complete genomes of Vibrios. Comparative genomics analysis found Vibrios encompass a steady core-genome and tremendous pan-genome with substantial gene gain and horizontal gene transfer events in the evolutionary history. Evolutionary analysis based on the core-genome tree suggested that V. fischeri emerged ~ 385 million years ago, along with the occurrence of cephalopods and the flourish of fish. The relatively large genomes, the high number of 16S rRNA gene copies, and the presence of R-M systems and CRISPR system help Vibrios live in various marine environments. Chitin-degrading related genes are carried in nearly all the Vibrio genomes. The number of chitinase genes in Vibrios has been extremely expanded compared to which in the most recent ancestor of the genus. The chitinase A genes were estimated to have evolved along with the genus, and have undergone significant purifying selective force to conserve the ancestral state. Vibrios have experienced extremely genome expansion events during their evolutionary history, allowing them to develop various functions to spread globally. Despite their close phylogenetic relationships, Vibrios were found to have a tremendous pan-genome with a steady core-genome, which indicates the highly plastic genome of the genus. Additionally, the existence of various chitin-degrading related genes and the expansion of chitinase A in the genus demonstrate the importance of the chitin utilization for Vibrios. Defensive systems in the Vibrio genomes may protect them from the invasion of external DNA. These genomic features investigated here provide a better knowledge of how the evolutionary process has forged Vibrio genomes to occupy various niches.
Fabiano L. Thompson - One of the best experts on this subject based on the ideXlab platform.
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The Biology of Vibrios - Taxonomy of the Vibrios
The Biology of Vibrios, 2014Co-Authors: Fabiano L. Thompson, Jean SwingsAbstract:The taxonomy of Vibrios was based on very few morphological features, including flagellation, morphology and curvature of the cells, and cultural aspects. This approach led to the description of many new, poorly characterized species. The DNA-DNA hybridization studies of researchers underpinned the taxonomy of Vibrios. This chapter discusses the historical underpinnings of Vibrio taxonomy and the traditional phenotypic basis of the taxonomy of Vibrio harveyi group. Subsequently, it provides a review of the recent improvements in the taxonomy of Vibrios that are mainly due to the application of genomic methodologies, including amplified fragment length polymorphism (AFLP), repetitive extragenic palindromic polymerase chain reaction (rep-PCR), DNA-DNA hybridization, and multilocus sequence analyses (MLSA). The authors conclude the chapter with a discussion on the development and application of an electronic prokaryotic taxonomy with Vibrios as a prototype. The current taxonomy of Vibrios is based mainly on genomic data. The taxonomy of Vibrios is being rapidly improved owing to the application of modern molecular techniques. New data gathered by these techniques will lead to a revision and improvement of the taxonomy of Vibrios in the next few years.
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Vibrio variabilis sp. nov. and Vibrio maritimus sp. nov., isolated from Palythoa caribaeorum
International Journal of Systematic and Evolutionary Microbiology, 2011Co-Authors: Luciane A. Chimetto, Ilse Cleenwerck, Ana Paula B. Moreira, Marcelo Brocchi, Anne Willems, Paul De Vos, Fabiano L. ThompsonAbstract:Two novel Vibrio isolates (R-40492(T) and R-40493(T)) originating from the zoanthid Palythoa caribaeorum in Brazil in 2005 were taxonomically characterized by means of a polyphasic approach comprising multilocus sequence analysis (MLSA), DNA-DNA hybridization (DDH), ΔT(m) analysis and phenotypic characterization. Phylogenetic analysis based on 16S rRNA gene sequences showed that R-40492(T) and R-40493(T) fell within the genus Vibrio and were most closely related to each other with 99% similarity; similarities of these two novel isolates towards Vibrio neptunius LMG 20536(T), Vibrio coralliilyticus LMG 20984(T), Vibrio nigripulchritudo LMG 3896(T), Vibrio sinaloensis LMG 25238(T) and Vibrio brasiliensis LMG 20546(T) varied between 97.1 and 98.5%. DDH experiments showed that the two isolates had less than 15% relatedness to the phylogenetically most closely related Vibrio species. R-40492(T) and R-40493(T) had 55-57% relatedness to each other. The ΔT(m) between R-40492(T) and R-40493(T) was 6.12 °C. In addition, MLSA of concatenated sequences (16S rRNA, ftsZ, gyrB, recA, rpoA, topA, pyrH and mreB; 6035 bp in length) showed that the two novel isolates formed a separate branch with less than 92% concatenated gene sequence similarity towards known species of Vibrios. Two novel species are proposed to accommodate these novel isolates, namely Vibrio variabilis sp. nov. (type strain, R-40492(T)=LMG 25438(T)=CAIM 1454(T)) and Vibrio maritimus sp. nov. (type strain, R-40493(T)=LMG 25439(T)=CAIM 1455(T)).
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Identification of Vibrio cholerae and Vibrio mimicus by multilocus sequence analysis (MLSA).
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 2008Co-Authors: Cristiane C. Thompson, Fabiano L. Thompson, Ana Carolina Paulo VicenteAbstract:Vibrio cholerae and Vibrio mimicus have similar phenotypes and genomes making rapid differentiation of these two species difficult. The first standard multilocus sequence analysis (MLSA) scheme for the identification of these species is described. A collection of 45 representative isolates from different geographical regions and hosts was examined using segments of the housekeeping genes pyrH, recA and rpoA. Overall, the closest phylogenetic neighbours of these species were Vibrio furnissii and Vibrio fluvialis. V. cholerae and V. mimicus formed separate species clusters on the basis of each gene, suggesting that these genes are useful as identification markers. These species clusters arose by the accumulation of point mutations. The pyrH gene showed the highest resolution for differentiating V. cholerae and V. mimicus. The maximum interspecies pyrH gene sequence similarity was 91 %. Clearly, V. mimicus strains were more heterogeneous than V. cholerae strains at the three loci. It is suggested that Vibrio species may be defined on the basis of MLSA data. A Vibrio species was defined as a group of strains forming a monophyletic group on the basis of these loci and with an intraspecific sequence similarity of at least 95 %. V. cholerae and V. mimicus isolates can be readily identified through the open database resource ‘The Taxonomy of Vibrios’ (http://www.taxVibrio.lncc.br/).
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Vibrio gallicus sp nov isolated from the gut of the french abalone haliotis tuberculata
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Tomoo Sawabe, Karin Hayashi, Jun Moriwaki, Richard Christen, Fabiano L. Thompson, Jean Swings, Philippe Potin, Yoshio EzuraAbstract:Five alginolytic, facultatively anaerobic, non-motile bacteria were isolated from the gut of the abalone Haliotis tuberculata. Phylogenetic analyses based on 16S rDNA data indicated that these strains are related to Vibrio wodanis, Vibrio salmonicida, Vibrio logei and Vibrio fischeri (but with <97 % 16S rRNA gene sequence similarity). DNA–DNA hybridization and fluorescence amplified fragment length polymorphism fingerprinting demonstrated that the five strains constituted a single species that was different from all currently known Vibrios. The name Vibrio gallicus sp. nov. (type strain, CIP 107863T=LMG 21878T=HT2-1T; DNA G+C content, 43·6–44·3 mol%) is proposed for this novel taxon. Several phenotypic features were disclosed that discriminated V. gallicus from other Vibrio species: V. gallicus can be differentiated from Vibrio halioticoli on the basis of four traits (β-galactosidase test and assimilation of three carbon compounds) and from Vibrio superstes by 16 traits.
Xiaolei Wang - One of the best experts on this subject based on the ideXlab platform.
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Comparative genomic analysis reveals the evolution and environmental adaptation strategies of Vibrios
BMC Genomics, 2018Co-Authors: Heyu Lin, Min Yu, Xiaolei Wang, Xiao-hua ZhangAbstract:BackgroundVibrios are among the most diverse and ecologically important marine bacteria, which have evolved many characteristics and lifestyles to occupy various niches. The relationship between genome features and environmental adaptation strategies is an essential part for understanding the ecological functions of Vibrios in the marine system. The advent of complete genome sequencing technology has provided an important method of examining the genetic characteristics of Vibrios on the genomic level.ResultsTwo Vibrio genomes were sequenced and found to occupy many unique orthologues families which absent from the previously genes pool of the complete genomes of Vibrios. Comparative genomics analysis found Vibrios encompass a steady core-genome and tremendous pan-genome with substantial gene gain and horizontal gene transfer events in the evolutionary history. Evolutionary analysis based on the core-genome tree suggested that V. fischeri emerged ~ 385 million years ago, along with the occurrence of cephalopods and the flourish of fish. The relatively large genomes, the high number of 16S rRNA gene copies, and the presence of R-M systems and CRISPR system help Vibrios live in various marine environments. Chitin-degrading related genes are carried in nearly all the Vibrio genomes. The number of chitinase genes in Vibrios has been extremely expanded compared to which in the most recent ancestor of the genus. The chitinase A genes were estimated to have evolved along with the genus, and have undergone significant purifying selective force to conserve the ancestral state.ConclusionsVibrios have experienced extremely genome expansion events during their evolutionary history, allowing them to develop various functions to spread globally. Despite their close phylogenetic relationships, Vibrios were found to have a tremendous pan-genome with a steady core-genome, which indicates the highly plastic genome of the genus. Additionally, the existence of various chitin-degrading related genes and the expansion of chitinase A in the genus demonstrate the importance of the chitin utilization for Vibrios. Defensive systems in the Vibrio genomes may protect them from the invasion of external DNA. These genomic features investigated here provide a better knowledge of how the evolutionary process has forged Vibrio genomes to occupy various niches.
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Comparative genomic analysis reveals the evolution and environmental adaptation strategies of Vibrios.
BMC Genomics, 2018Co-Authors: Heyu Lin, Xiaolei Wang, Xiao-hua ZhangAbstract:Vibrios are among the most diverse and ecologically important marine bacteria, which have evolved many characteristics and lifestyles to occupy various niches. The relationship between genome features and environmental adaptation strategies is an essential part for understanding the ecological functions of Vibrios in the marine system. The advent of complete genome sequencing technology has provided an important method of examining the genetic characteristics of Vibrios on the genomic level. Two Vibrio genomes were sequenced and found to occupy many unique orthologues families which absent from the previously genes pool of the complete genomes of Vibrios. Comparative genomics analysis found Vibrios encompass a steady core-genome and tremendous pan-genome with substantial gene gain and horizontal gene transfer events in the evolutionary history. Evolutionary analysis based on the core-genome tree suggested that V. fischeri emerged ~ 385 million years ago, along with the occurrence of cephalopods and the flourish of fish. The relatively large genomes, the high number of 16S rRNA gene copies, and the presence of R-M systems and CRISPR system help Vibrios live in various marine environments. Chitin-degrading related genes are carried in nearly all the Vibrio genomes. The number of chitinase genes in Vibrios has been extremely expanded compared to which in the most recent ancestor of the genus. The chitinase A genes were estimated to have evolved along with the genus, and have undergone significant purifying selective force to conserve the ancestral state. Vibrios have experienced extremely genome expansion events during their evolutionary history, allowing them to develop various functions to spread globally. Despite their close phylogenetic relationships, Vibrios were found to have a tremendous pan-genome with a steady core-genome, which indicates the highly plastic genome of the genus. Additionally, the existence of various chitin-degrading related genes and the expansion of chitinase A in the genus demonstrate the importance of the chitin utilization for Vibrios. Defensive systems in the Vibrio genomes may protect them from the invasion of external DNA. These genomic features investigated here provide a better knowledge of how the evolutionary process has forged Vibrio genomes to occupy various niches.
