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Comparative Genomic Analyses of Multiple Pseudomonas Strains Infecting Corylus avellana Trees Reveal the Occurrence of Two Genetic Clusters with Both Common and Distinctive Virulence and Fitness Traits.

Marcelletti S, Scortichini M - PLoS ONE (2015)

Bottom Line: Between these two clusters, no recombination event was found.Homologue genes of the antimetabolite mangotoxin and ice nucleation activity clusters were found solely in all P. syringae pathovar strains, whereas the siderophore yersiniabactin was only present in P. avellanae.By contrast, they do not have genes coding for indolacetic acid and anti-insect toxin.

View Article: PubMed Central - PubMed

Affiliation: Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (C.R.A.)-Centro di Ricerca per la Frutticoltura, Via di Fioranello 52, I-00134, Roma, Italy.

ABSTRACT
The European hazelnut (Corylus avellana) is threatened in Europe by several pseudomonads which cause symptoms ranging from twig dieback to tree death. A comparison of the draft genomes of nine Pseudomonas strains isolated from symptomatic C. avellana trees was performed to identify common and distinctive genomic traits. The thorough assessment of genetic relationships among the strains revealed two clearly distinct clusters: P. avellanae and P. syringae. The latter including the pathovars avellanae, coryli and syringae. Between these two clusters, no recombination event was found. A genomic island of approximately 20 kb, containing the hrp/hrc type III secretion system gene cluster, was found to be present without any genomic difference in all nine pseudomonads. The type III secretion system effector repertoires were remarkably different in the two groups, with P. avellanae showing a higher number of effectors. Homologue genes of the antimetabolite mangotoxin and ice nucleation activity clusters were found solely in all P. syringae pathovar strains, whereas the siderophore yersiniabactin was only present in P. avellanae. All nine strains have genes coding for pectic enzymes and sucrose metabolism. By contrast, they do not have genes coding for indolacetic acid and anti-insect toxin. Collectively, this study reveals that genomically different Pseudomonas can converge on the same host plant by suppressing the host defence mechanisms with the use of different virulence weapons. The integration into their genomes of a horizontally acquired genomic island could play a fundamental role in their evolution, perhaps giving them the ability to exploit new ecological niches.

No MeSH data available.


Related in: MedlinePlus

Structure of the genomic island Pcor GI1 of about 20 kb found in all nine pseudomonad strains infecting Corylus avellana trees.It was obtained using the SEED viewer comparative tool. The genomic structure of the island resulted conserved among the strains. Two representative structure regarding Pseudomonas syringae pv. syringae CRAFRU 11 and P. avellanae BPIC 631 are shown. Gene legend is shown in S2 Table.
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pone.0131112.g006: Structure of the genomic island Pcor GI1 of about 20 kb found in all nine pseudomonad strains infecting Corylus avellana trees.It was obtained using the SEED viewer comparative tool. The genomic structure of the island resulted conserved among the strains. Two representative structure regarding Pseudomonas syringae pv. syringae CRAFRU 11 and P. avellanae BPIC 631 are shown. Gene legend is shown in S2 Table.

Mentions: The search for putative genomic islands within the genomes of the nine pseudomonads revealed the presence of Pcor GI1, a genomic island of approximately 20 kb present in all strains. The islands Pave GI2 and Pave GI3, of approximately 11.5 and 5 kbs, respectively, were only present in the P. avellanae strains. No variation in the sequences of these islands was found among the pseudomonads. Graphical representations of these genomic islands obtained with Seed Viewer (Fig 6) and R software (A, B, C in S7 Fig) show that Pcor GI1 contains many proteins of the hrp/hrc type III secretion system cluster. These include HrpK1, a member of a conserved family of the type III secretion system translocon components, and Hrc QA and Hrc QB, conserved component of the bacterial type III secretion system (Table 5 and S2 Table). Of the proteins found only in the P. avellanae strains, Pave GI2 contains a methyl-accepting chemotaxis protein, whereas Pave GI3 contains proteins related to the prophage PSPPH04.


Comparative Genomic Analyses of Multiple Pseudomonas Strains Infecting Corylus avellana Trees Reveal the Occurrence of Two Genetic Clusters with Both Common and Distinctive Virulence and Fitness Traits.

Marcelletti S, Scortichini M - PLoS ONE (2015)

Structure of the genomic island Pcor GI1 of about 20 kb found in all nine pseudomonad strains infecting Corylus avellana trees.It was obtained using the SEED viewer comparative tool. The genomic structure of the island resulted conserved among the strains. Two representative structure regarding Pseudomonas syringae pv. syringae CRAFRU 11 and P. avellanae BPIC 631 are shown. Gene legend is shown in S2 Table.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492584&req=5

pone.0131112.g006: Structure of the genomic island Pcor GI1 of about 20 kb found in all nine pseudomonad strains infecting Corylus avellana trees.It was obtained using the SEED viewer comparative tool. The genomic structure of the island resulted conserved among the strains. Two representative structure regarding Pseudomonas syringae pv. syringae CRAFRU 11 and P. avellanae BPIC 631 are shown. Gene legend is shown in S2 Table.
Mentions: The search for putative genomic islands within the genomes of the nine pseudomonads revealed the presence of Pcor GI1, a genomic island of approximately 20 kb present in all strains. The islands Pave GI2 and Pave GI3, of approximately 11.5 and 5 kbs, respectively, were only present in the P. avellanae strains. No variation in the sequences of these islands was found among the pseudomonads. Graphical representations of these genomic islands obtained with Seed Viewer (Fig 6) and R software (A, B, C in S7 Fig) show that Pcor GI1 contains many proteins of the hrp/hrc type III secretion system cluster. These include HrpK1, a member of a conserved family of the type III secretion system translocon components, and Hrc QA and Hrc QB, conserved component of the bacterial type III secretion system (Table 5 and S2 Table). Of the proteins found only in the P. avellanae strains, Pave GI2 contains a methyl-accepting chemotaxis protein, whereas Pave GI3 contains proteins related to the prophage PSPPH04.

Bottom Line: Between these two clusters, no recombination event was found.Homologue genes of the antimetabolite mangotoxin and ice nucleation activity clusters were found solely in all P. syringae pathovar strains, whereas the siderophore yersiniabactin was only present in P. avellanae.By contrast, they do not have genes coding for indolacetic acid and anti-insect toxin.

View Article: PubMed Central - PubMed

Affiliation: Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (C.R.A.)-Centro di Ricerca per la Frutticoltura, Via di Fioranello 52, I-00134, Roma, Italy.

ABSTRACT
The European hazelnut (Corylus avellana) is threatened in Europe by several pseudomonads which cause symptoms ranging from twig dieback to tree death. A comparison of the draft genomes of nine Pseudomonas strains isolated from symptomatic C. avellana trees was performed to identify common and distinctive genomic traits. The thorough assessment of genetic relationships among the strains revealed two clearly distinct clusters: P. avellanae and P. syringae. The latter including the pathovars avellanae, coryli and syringae. Between these two clusters, no recombination event was found. A genomic island of approximately 20 kb, containing the hrp/hrc type III secretion system gene cluster, was found to be present without any genomic difference in all nine pseudomonads. The type III secretion system effector repertoires were remarkably different in the two groups, with P. avellanae showing a higher number of effectors. Homologue genes of the antimetabolite mangotoxin and ice nucleation activity clusters were found solely in all P. syringae pathovar strains, whereas the siderophore yersiniabactin was only present in P. avellanae. All nine strains have genes coding for pectic enzymes and sucrose metabolism. By contrast, they do not have genes coding for indolacetic acid and anti-insect toxin. Collectively, this study reveals that genomically different Pseudomonas can converge on the same host plant by suppressing the host defence mechanisms with the use of different virulence weapons. The integration into their genomes of a horizontally acquired genomic island could play a fundamental role in their evolution, perhaps giving them the ability to exploit new ecological niches.

No MeSH data available.


Related in: MedlinePlus