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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

Venn diagram of the type III secretion system effector genes complement of nine pseudomonad strains infecting Corylus avellana trees.Pave: Pseudomonas avellanae; Psave: P. syringae pv. avellanae; Psc: P. s. pv. coryli; Pss: P. s. pv. syringae. *: not present in P. avellanae BPIC 631.
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pone.0131112.g005: Venn diagram of the type III secretion system effector genes complement of nine pseudomonad strains infecting Corylus avellana trees.Pave: Pseudomonas avellanae; Psave: P. syringae pv. avellanae; Psc: P. s. pv. coryli; Pss: P. s. pv. syringae. *: not present in P. avellanae BPIC 631.

Mentions: A comparison of the effector repertoires of the nine strains of phytopathogenic pseudomonads to infect C. avellana trees was completed based on the complete dataset of effector proteins found in the website database http://www.pseudomonas-syringae.org., e-10, length hit > 60%. The analysis revealed a core set of six putative effector genes that are conserved across all strains studied (Fig 5): avrE1, hopAA1, hopAI1, hopAZ3, hopM1 and hopAH1, the latter of which was found to be absent in P. avellanae BPIC 631. In addition, P. avellanae and P. syringae pathovars avellanae and syringae showed a unique set of effector proteins with hopZ3 and avrB3 solely present in the P. syringae pathovars syringae and avellanae, respectively. Interestingly, P. avellanae had a significant higher number of effector proteins and unique effector protein genes. A comparison of the effector genes performed between the P. avellanae strains revealed that only BPIC 631 contained hopBD1 (S4 Fig), whereas none of the three strains isolated in Italy possessed any unique effector gene. A comparison performed among the P. syringae pathovars strains infecting C. avellana showed that P. s. pv. coryli NCPPB 4273 and P. s. pv. syringae CRAFRU 11 showed distinct and unique repertoires of effector genes. Only P. s. pv. coryli had hopA2, hopAS1, hopAU1 and hopAV1, while only P. s. pv. syringae CRAFRU 11 had hopAX and hopZ3 (S5 Fig). The dendrogram of the relationships between the effector protein gene repertoires of the nine pseudomonads to infect C. avellana and obtained using UPGMA algorithm (S6 Fig) once more confirms the distinctiveness of the P. avellanae from the P. syringae pathovar strains.


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)

Venn diagram of the type III secretion system effector genes complement of nine pseudomonad strains infecting Corylus avellana trees.Pave: Pseudomonas avellanae; Psave: P. syringae pv. avellanae; Psc: P. s. pv. coryli; Pss: P. s. pv. syringae. *: not present in P. avellanae BPIC 631.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131112.g005: Venn diagram of the type III secretion system effector genes complement of nine pseudomonad strains infecting Corylus avellana trees.Pave: Pseudomonas avellanae; Psave: P. syringae pv. avellanae; Psc: P. s. pv. coryli; Pss: P. s. pv. syringae. *: not present in P. avellanae BPIC 631.
Mentions: A comparison of the effector repertoires of the nine strains of phytopathogenic pseudomonads to infect C. avellana trees was completed based on the complete dataset of effector proteins found in the website database http://www.pseudomonas-syringae.org., e-10, length hit > 60%. The analysis revealed a core set of six putative effector genes that are conserved across all strains studied (Fig 5): avrE1, hopAA1, hopAI1, hopAZ3, hopM1 and hopAH1, the latter of which was found to be absent in P. avellanae BPIC 631. In addition, P. avellanae and P. syringae pathovars avellanae and syringae showed a unique set of effector proteins with hopZ3 and avrB3 solely present in the P. syringae pathovars syringae and avellanae, respectively. Interestingly, P. avellanae had a significant higher number of effector proteins and unique effector protein genes. A comparison of the effector genes performed between the P. avellanae strains revealed that only BPIC 631 contained hopBD1 (S4 Fig), whereas none of the three strains isolated in Italy possessed any unique effector gene. A comparison performed among the P. syringae pathovars strains infecting C. avellana showed that P. s. pv. coryli NCPPB 4273 and P. s. pv. syringae CRAFRU 11 showed distinct and unique repertoires of effector genes. Only P. s. pv. coryli had hopA2, hopAS1, hopAU1 and hopAV1, while only P. s. pv. syringae CRAFRU 11 had hopAX and hopZ3 (S5 Fig). The dendrogram of the relationships between the effector protein gene repertoires of the nine pseudomonads to infect C. avellana and obtained using UPGMA algorithm (S6 Fig) once more confirms the distinctiveness of the P. avellanae from the P. syringae pathovar strains.

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