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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

Presence/absence of putative homolog proteins in nine pseudomonad strains infecting Corylus avellana trees.The indication concerns the presence of copper resistance genes, bacteriocins, and the flagellin cluster (A), and ice nucleation activity, pectic enzymes, sucrose metabolism, and siderophores (B). Strain legend is shown in Table 1.
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pone.0131112.g008: Presence/absence of putative homolog proteins in nine pseudomonad strains infecting Corylus avellana trees.The indication concerns the presence of copper resistance genes, bacteriocins, and the flagellin cluster (A), and ice nucleation activity, pectic enzymes, sucrose metabolism, and siderophores (B). Strain legend is shown in Table 1.

Mentions: No homologues proteins related to lantibiotic detoxification were found in any strain. By contrast, the nine pseudomonad strains contained an array of homologs involved in the detoxification of antibiotics such as multidrug resistance protein, beta-lactamase, penicillin, MarC and MarR (Fig 7B). Among the bacteriocins, the pyocins were found to be the most broadly distributed, especially within the P. syringae pathovars. However, the three P. avellanae strains isolated in Italy did not possess any homolog related to bacteriocin production (Fig 8A). Some homologues proteins of the Cop operon related to copper resistance were found in all of the nine pseudomonads infecting C. avellana trees. In particular, CopA, CopB and CopD were present in all nine strains. Of note, only P. s. pv. syringae CRAFRU 12 contained all of the homologues within this cluster (Fig 8A), including CopC, CopR and CopS. (Fig 8A). All nine pseudomonads contain the same set of the fli cluster genes coding for flagellin.


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)

Presence/absence of putative homolog proteins in nine pseudomonad strains infecting Corylus avellana trees.The indication concerns the presence of copper resistance genes, bacteriocins, and the flagellin cluster (A), and ice nucleation activity, pectic enzymes, sucrose metabolism, and siderophores (B). Strain legend is shown in Table 1.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131112.g008: Presence/absence of putative homolog proteins in nine pseudomonad strains infecting Corylus avellana trees.The indication concerns the presence of copper resistance genes, bacteriocins, and the flagellin cluster (A), and ice nucleation activity, pectic enzymes, sucrose metabolism, and siderophores (B). Strain legend is shown in Table 1.
Mentions: No homologues proteins related to lantibiotic detoxification were found in any strain. By contrast, the nine pseudomonad strains contained an array of homologs involved in the detoxification of antibiotics such as multidrug resistance protein, beta-lactamase, penicillin, MarC and MarR (Fig 7B). Among the bacteriocins, the pyocins were found to be the most broadly distributed, especially within the P. syringae pathovars. However, the three P. avellanae strains isolated in Italy did not possess any homolog related to bacteriocin production (Fig 8A). Some homologues proteins of the Cop operon related to copper resistance were found in all of the nine pseudomonads infecting C. avellana trees. In particular, CopA, CopB and CopD were present in all nine strains. Of note, only P. s. pv. syringae CRAFRU 12 contained all of the homologues within this cluster (Fig 8A), including CopC, CopR and CopS. (Fig 8A). All nine pseudomonads contain the same set of the fli cluster genes coding for flagellin.

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